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Article

Sustainable Recovery of the Health of Soil with Old Petroleum Hydrocarbon Contamination through Individual and Microorganism-Assisted Phytoremediation with Lotus corniculatus

by
Rimas Meištininkas
1,*,
Irena Vaškevičienė
1,
Agnieszka I. Piotrowicz-Cieślak
2,
Magdalena Krupka
2 and
Jūratė Žaltauskaitė
1,3
1
Laboratory of Heat Equipment Research and Testing, Lithuanian Energy Institute, Breslaujos 3, LT44404 Kaunas, Lithuania
2
Department of Plant Physiology, Genetics and Biotechnology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-718 Olsztyn, Poland
3
Department of Environmental Sciences, Vytautas Magnus University, Universiteto 10, LT53361 Akademija, Lithuania
*
Author to whom correspondence should be addressed.
Sustainability 2024, 16(17), 7484; https://doi.org/10.3390/su16177484
Submission received: 18 July 2024 / Revised: 25 August 2024 / Accepted: 27 August 2024 / Published: 29 August 2024
(This article belongs to the Section Pollution Prevention, Mitigation and Sustainability)
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Abstract

:
Due to the large number of areas contaminated with TPH, there is significant interest in biological remediation technology research, offering a comprehensive and sustainable approach to soil decontamination and health recovery at the same time. This study aimed to investigate the effectiveness of remediating TPH-contaminated soil (6120 mg kg−1) using Lotus corniculatus along with a microorganism consortium (GTC-GVT/2021) isolated from historic TPH-contaminated sites. This study evaluated the removal of TPH and soil health recovery through changes in soil nutrient content, soil enzymatic activity, and the microbiological community. The growth of L. corniculatus was reduced in TPH-contaminated soil, particularly affecting root biomass by 52.17%. Applying inoculum positively affected total plant biomass in uncontaminated (51.44%) and contaminated (33.30%) soil. The GTC-GVT/2021 inoculum significantly enhanced the degradation of TPH in contaminated soil after 90 days by 20.8% and in conjunction with L. corniculatus by 26.33% compared to the control. The soil enzymatic activity was more pronounced in TPH-contaminated soil treatments, and in most cases, the presence of L. corniculatus and inoculum led to a significantly higher soil enzymatic activity. The cultivation of L. corniculatus and the inoculum resulted in an increased concentration of inorganic P, NH4+, and water-soluble phenols in the soil, while no rise in NO3− was observed.

1. Introduction

Petroleum hydrocarbons are the basic constituents of crude oil, natural gas, and other essential energy sources [1]. They are the primary elements found in petroleum and natural gas, which are utilised as fuels, lubricants, and raw materials for the production of various products such as plastics, rubbers, solvents, explosives, and many other industrial chemicals [2]. Petroleum is commonly used for powering vehicles and machines and can be transformed into many different substances. The extraction, processing, and availability of petroleum play significant roles in the world’s economy and global politics [3].
Petroleum hydrocarbon pollution poses risks not only to the environment but also to human health. They are key contributors to climate change, ozone layer depletion, and the increase in cancer and respiratory disorders in humans [4]. Soil contamination by petroleum hydrocarbons caused by oil spills and leakages can have devastating effects on soil health, particularly on microorganisms, reducing their number and activity, even at low concentrations [5]. They can deplete the biodiversity of microorganisms and plants, disrupt ecological balance, and impoverish soil fertility [6]. Therefore, soil contamination by petroleum hydrocarbons is a pressing environmental concern due to these compounds’ toxic, mutagenic, and carcinogenic nature [7].
The remediation of contaminated soils is not just a necessity but a crucial step towards ensuring a safe environment and promoting sustainable development. Remediation methods can be broadly classified as in situ and ex situ techniques [8]. In situ methods treat the contaminated soil in its original location, while ex situ methods involve the removal of the contaminated soil for treatment [9]. The implementation of both methods has its pros and cons, and the selection depends on various factors such as the depth and type of the pollutant, geographical location, degree of pollution, and cost [8,10]. Physical and chemical remediation methods, while effective, are often expensive and unsustainable. For instance, chemical treatment could cause secondary soil pollution by solvents and other chemical agents [11]. In contrast, biological remediation, particularly phytoremediation and microorganism-assisted (augmented) phytoremediation is gaining more attention due to its cost-effectiveness and eco-friendliness [12,13,14].
Different types of microorganisms play a unique role in various biological processes related to the breakdown of hazardous organic pollutants. Together, they are able to transform complex organic pollutants into simpler compounds. Bacteria are the main decomposers of hydrocarbons in the environment. Some species produce a stable biosurfactant, tolerate high crude oil concentrations, and degrade aliphatics, monoaromatics, and polyaromatics [15]. Fungi have a larger surface area for biosorption and enzyme secretion, making them more efficient in biodegrading long-chain petroleum hydrocarbons [16]. Yeast degrades long-chain alkanes into shorter-chain compounds, reducing the carbon content and enhancing the flowability of heavy crude oil. It also produces organic solvents such as acids and alcohols that react with carbonate minerals in reservoir pores, reducing oil viscosity and improving petroleum hydrocarbon recovery rates [17].
The basic mechanism for the natural attenuation of contaminants in the soil is the biodegradation by indigenous microorganisms. However, when the contaminants exert a toxic effect on the indigenous microorganisms, the contaminant degradation could be fostered by bioaugmentation, i.e., inoculation with exogenous microorganisms. Microorganisms’ efficiency in degrading contaminants is dependent on chemical, microorganism species, and environmental conditions [18]. Implementing a microbial consortium instead of a single microbial strain for bioremediation offers distinct advantages. It provides the requisite metabolic diversity and robustness essential for effective field applications. Since microorganisms inhabiting petroleum products have contaminated sites for a long time, they often adapt to pollution and are resistant to toxicants. Microorganism consortium isolated from contaminated soils might be adapted to a specific type of pollution and have resistance to toxic agents. This could make them potentially more effective in the field of petroleum hydrocarbon bioremediation applications [19].
Plants can also contribute to the remediation process, as they stimulate microbial activity in the soil through their root exudates, promoting the degradation of petroleum hydrocarbons. Moreover, plants can improve soil structure and fertility, creating a more favourable environment for microbial activity and thus enhancing the bioremediation process [20]. Legume plants (Fabaceae) are an up-and-coming group for decontaminating petroleum-hydrocarbon-polluted soil as they can establish symbiotic interactions with rhizobia and arbuscular mycorrhizal fungi, which helps them acquire various nutrients, including nitrogen and phosphorous [21]. However, the effectiveness of this combined approach can be influenced by multiple factors, including the type and concentration of the pollutants, the characteristics of the soil, and the specific species of microorganisms and plants used [11,22].
The perennial legume plant species Lotus corniculatus L. from the Fabaceae family was used for this study. This plant species was chosen for its tolerance to petroleum hydrocarbons, high phytoremediation efficiency, and low soil fertility requirements [23,24]. L. corniculatus is typically grown as fodder plants, has high nutritional value, and can enrich the soil with nitrogen compounds [25,26]. L. corniculatus is characterised by morphological resistance to petroleum hydrocarbons, and also considering the phytoremediation potential can be used to accelerate the decomposition of petroleum products such as diesel, crude oil, fuel oil, and others in the soil [27]. However, more research is still needed on using L. corniculatus together with microbial inoculums in the augmented phytoremediation process.
Since there are millions of TPH-contaminated sites around the world, there is a growing global interest in environmentally friendly, low-cost, and non-secondary pollution-generating technologies for the treatment of TPH-contaminated soil. These technologies aim to take a sustainable approach to soil health, not only decontaminating the soil but also fully restoring its fertility and microbiological activity, in compliance with the ES soil strategy and sustainable development goals. To address these gaps, this study aimed to investigate the effectiveness of TPH-contaminated soil remediation by L. corniculatus in conjunction with a microorganism consortium (GTC-GVT/2021) isolated from historic TPH-contaminated sites. This study assessed TPH destruction, plant biomass production, changes in soil nutrient content, soil enzymatic activity, and microbiological community carbon substrate utilisation profiles.

2. Materials and Methods

2.1. Soil, Plant and Microbiological Inoculum Sources

The soil was obtained from a historically TPH-polluted area in southern Lithuania’s Varena district (54.361582, 24.662247 WGS). The area had been contaminated with petroleum hydrocarbons since the time of the Soviet Union due to the presence of a nearby boiler house where petroleum products (fuel oil) were burned. Sampled soil (sampled at 50 cm depth) was classified as sandy loam. The contamination level in total petroleum hydrocarbons (TPHs) was 6120 ± 49 mg kg−1. The control (unpolluted) sandy loam soil was taken from an adjacent uncontaminated area. Characteristics of control and contaminated soil are provided in Table 1. Sampled soils were sieved and homogenised.
The seeds of Lotus corniculatus L. were provided by the Lithuanian Research Center for Agriculture and Forestry (Akademija, Lithuania).
The microbiological inoculum GTC-GVT/2021 was prepared at the Nature Research Center (Vilnius, Lithuania). It consists of various types of bacteria (Klebsiella sp., Acinetobacter sp., Rhodococcus sp., Pseudomonas sp.), fungi (Trichoderma sp., Sarocladium sp., Penicillium sp.), and yeasts (Yarrowia sp., Rhodotorula sp., Sporobolomyces sp.). All microorganisms were isolated and selected from long-term TPH-polluted soils in Lithuania (patent application number: 7 February 2024 Nr. LT2024 507).

2.2. Experimental Design

To assess the bioremediation of TPH, the following treatments were performed: (i) C: control (unpolluted) unplanted soil; (ii) CP: control (unpolluted) soil planted with L. corniculatus; (iii) CM: control (unpolluted) soil with GTC-GVT/2021 inoculum; (iv) CPM: control (unpolluted) soil planted with L. corniculatus + GTC-GVT/2021 inoculum; (v) CH: TPH-contaminated unplanted soil; (vi) CHP: TPH-contaminated soil planted with L. corniculatus; (vii) CHM: TPH-contaminated soil with GTC-GVT/2021 inoculum; (vii) CHPM: TPH-contaminated soil planted with L. corniculatus + GTC-GVT/2021 inoculum). All treatments were produced in four replicates.
The experiment was divided into two groups: treatments with TPH-contaminated soil and the same treatments with non-contaminated soil to evaluate the differences in plant growth parameters and soil nutrient amount changes.
The 25 cm deep plastic pots were filled with 4 kg of soil each; a total of 32 pots were used in the experiment. To avoid waterlogging, the pots were perforated at the bottom. The plant growth chamber with a 14/10 h photoperiod and a temperature of 23/14 ± 1 °C (day/night) was used to carry out the experiment. The photoactive radiation intensity was maintained at the level of ~460 µmol m−2 s−1 using dual-spectrum HPS lamps (Venture Sunmaster, 3 × 600 W). The relative air humidity in the chamber (RH) was maintained at 55–60%. In the phytoremediation treatments (CP, CPM, CHP, CHPM), ten seeds of L. corniculatus were sown in each pot. After germination, the seedlings were thinned to leave five uniform seedlings per pot. The pots were rotated in random order every day to avoid possible differences in the levels of photoactive radiation and temperature inside the growth chamber.
To assess the microbiological inoculum effect on TPH biodegradation, the GTC-GVT/2021 inoculum at 5.9 mL kg−1 (according to manufacturer instructions) was added to the soil and mixed with an electric mixer to allow the microorganisms to colonise the soil (CM, CPM, CHM, CHPM treatments).
The experiment was conducted for 90 days to ensure the plants had enough time for maturation, flowering, and root system development. The legume plants were harvested 90 days after sowing (90 DAS). The harvested shoots and roots of L. corniculatus were dried in an oven (70 °C) until a constant weight.
Soil samples for TPH concentration determination were collected at the beginning, in the middle (after 45 days), and at the end of the experiment (after 90 days). Gas chromatography (Shimadzu GC-2010) (Kyoto, Japan) was used for quantitative soil analysis of TPH, following the ISO 16703:2004 standard for petroleum hydrocarbons (C10–C40) determination in soil [28].

2.3. Measurement Methods

Soil samples for nutrients (NO3−, NH4+, inorganic P) and water-soluble phenol chemical determination were taken after the plant harvest and stored at 4 °C. The soil samples were sieved with a 1 mm sieve to avoid impurities, and soil extracts (1:10 w/w with distilled water) were prepared. To measure the concentration of nitrates (NO3−), the Griess method [29] was implemented, and the Malachite green method [30] was used to measure the concentration of inorganic P. The Berthelot reaction [31] was used to determine the concentration of ammonium (NH4+). Concentrations of water-soluble phenols were determined using the Folin–Ciocalteau reagent [32]. Nitrates, inorganic P, ammonium, and water-soluble phenols were measured spectrophotometrically (SPECTROSTAR Nano, Ortenberg, Germany) at wavelengths of 725 nm, 660 nm, 540 nm, and 630 nm, respectively.
Soil dehydrogenase activity was measured by mixing soil samples with 5 mL of phosphate buffer (pH 7.2), 0.2 g CaCO3, and 1 mL of 3% (v/w) TTC (2,3,5-Triphenyltetrazolium chloride, Merck, Poland). Prepared extracts were incubated at 37 °C for 24 h. After 24 h incubation, the assays were centrifuged at 3000 rpm for 10 min. The supernatant was discarded, and 5 mL of methanol was added to the samples. Samples were shaken at 100 rpm for 5 min on a laboratory shaker (DLAB Science, Poznań, Poland). Then, another 5 mL of methanol was added. Samples were shaken again for 5 min. Then, assays were centrifuged at 3000 rpm for 10 min. The absorbance of the prepared supernatant was measured at 485 nm wavelength. TPF concentration was calculated according to the Lambert–Beer law using the molar extinction coefficient of 15,603 M−1 × cm−1 for TPF in methanol, according to Veas-Arancibia (1986) [33].
Soil phosphatase activity was measured according to Alef and Nannipieri (1995) [34] with modifications. Before the assay, a universal buffer was prepared. To 1 L of water, 12.1 g of Tris(hydroxymethyl)aminomethane (Sigma-Aldrich, Burlington, MA, USA), 11.6 g of maleic acid (Merck, Poznań, Poland), 14 g of citric acid (Chempur, Piekary Śląskie, Poland), 6.3 g of boric acid (Chempur, Poland), and 488 mL of 1M NaOH was added. Immediately before the assay, a portion of the universal buffer was taken, and the pH was adjusted to 6.5 (acid phosphatase) and 11 (alkaline phosphatase). Then, 1 g of soil was mixed with 4 mL of the suitable buffer and 1 mL of 10 mM p-nitrophenyl phosphate (Merck, Poland). Samples were incubated at 37 °C for 1 h. After incubation, samples were centrifuged at 2000 rpm for 5 min. Supernatants were transferred to new falcon tubes, and then 4 mL of 0.5 M NaOH and 1 mL of 0.5 M CaCl2 were dosed to samples. Samples were shaken at 100 rpm for 5 min on a laboratory shaker (DLAB Science, Poland). After that, samples were centrifuged at 2000 rpm for 5 min. The absorbance of the supernatant was measured at the wavelength of 410 nm, and p-nitrophenol concentration was obtained according to the Lambert–Beer law using the molar extinction coefficient of 17.500 M−1 × cm−1 according to Bingham and Garver (1999) [35].
Soil urease activity was measured according to Zhang et al. (2011) [36] and Bonmati et al. (1985) [37] with modifications. Then, 5 mL of 0.1 M citrate solution and 5 mL of 10% urea were added to tubes with 5 g of soil samples. The assays were then incubated at 37 °C for a period of 2 h. The suspension was filtered, and 1 mL of filtrate was taken. Then, 4 mL of phenol, 1 mL of 1% nitroprusside, and 5 mL of alkaline hypochlorite were added. The assays were homogenised and incubated for 30 min in the dark. The absorbance of the mixture was measured at the wavelength of 625 nm.
The soil microbial communities’ ability to utilise various carbon sources (CLPPs) was evaluated using Biolog EcoPlate [38]. Each plate contained 96 wells with 31 different carbon sources and a blank well without a carbon source; each configuration was replicated thrice. The reduction in tetrazolium violet redox dye indicated the rate of carbon source utilisation. When microorganisms utilised the substrate, the dye changed from colourless to purple [39]. To provide an Ecoplate test, 5 g of soil was mixed with 50 mL distilled water and shaken for 60 min at 20 °C, then left to settle for 10 min. The soil extract was diluted 100 times with distilled water, and 150 μL of the prepared suspension was inoculated in each well of Biolog Ecoplate and incubated at 28 °C. Absorbance at 595 nm was measured (SPECTROSTAR Nano, Ortenberg, Germany) after 24, 48, 72, and 96 incubation hours. The microbial activity in each microplate was quantified as the average well-colour development (AWCD) [40]. The average well-colour development (AWCD) was calculated using the formula [AWCD = ΣOptical density/31].

2.4. Statistical Analysis

Statistical analyses were performed using STATISTICA 12 software. Fisher’s Least Significant Difference (LSD) test compared the significant means of plant biomass and soil parameters. Analysis of Variance (ANOVA) F-test was performed comparing the influence levels of L. corniculatus and GTC-GVT/2021 inoculum between different treatments. The results were deemed significant if p ≤ 0.05.
The Pearson correlation coefficient was calculated to evaluate the relationship between TPH residual concentration and soil physicochemical and enzymatic characteristics after treatments. The results were deemed significant if p ≤ 0.05.
The removal efficiency of TPH was calculated using the following formula: [(initial TPH concentration − TPH concentration after treatment)/initial TPH concentration] × 100.

3. Results

3.1. TPH Bioremediation Efficiency

Total TPH concentration decreased in all treatments. After six weeks (45 days), it was found that the CHPM treatment had the highest TPH degradation efficiency at 56.95%, while the control (CH) unplanted treatment had the lowest efficiency at 25.27% (Figure 1). By the end of 12 weeks, the TPH removal efficiency in these treatments reached 76.93% and 50.60%, respectively. The TPH concentration between CHP and CHM varied slightly during the whole bioremediation period, though the CHM treatment tended to have a more significant positive impact on TPH degradation efficiency, with a 20.8% increase compared to the control (CH), while the CHP treatment showed an 18.15% increase respectively. Soil remediation with L. corniculatus in conjunction with GTC-GVT/2021 inoculum generated a synergistic effect, resulting in a 26.33% higher TPH degradation compared with the control unplanted CH treatment (LSD, p < 0.05) and was 8.18% higher compared to single treatment with L. corniculatus.

3.2. Activity of Soil Enzymes

Soil enzyme activity was not significantly suppressed by soil contamination with petroleum hydrocarbons. Soil remediation by single phytoremediation, augmentation with GTC-GVT/2021 inoculum, and their combination resulted in a substantial increase in soil enzyme activity compared to the initial values.
Dehydrogenase activity in the uncontaminated soil in most treatments (C, CP, CM) did not change during the treatment (LSD, p > 0.05) and only in the treatment with L. corniculatus and GTC-GVT/2021 inoculum (CPM) dehydrogenase activity significantly increased by 21.24% (Figure 2(1A)). The soil dehydrogenase activity was higher in TPH-contaminated soil treatments (Figure 2(1B)) and was significantly higher than in the initial soil before the treatment (LSD, p < 0.05). The highest activity was measured in the treatment where L. corniculatus was grown (CHP), which exceeded the initial enzyme activity by 2.58 times. The dehydrogenase activity during the contaminated soil treatment with inoculum GTC-GVT/2021 (CHM) and the combination of plants and inoculum GTC-GVT/2021 (CHPM) increased by 63.23% and 74.43%, respectively. The lowest dehydrogenase activity increase was observed in the CH treatment (31.89%).
The pattern of changes in soil urease activity closely resembled that of dehydrogenase activity. The primary distinction is that in the case of urease, the trend is more evident: in uncontaminated soil, the enzyme activity in all treatments after the experiment was significantly lower, while in TPH-contaminated soil, it was considerably higher (LSD, p < 0.05) than in the initial soil (Figure 2(2A,B)). The highest soil urease activity was recorded in the treatment with L. corniculatus (CHP), exceeding the initial enzyme activity by 2.74 times. Soil urease activity increased by 2.05 times during contaminated soil treatment with inoculum GTC-GVT/2021 (CHM) and by 1.73 times with the combination of plants and inoculum GTC-GVT/2021 (CHPM).
In the uncontaminated soil, all treatments (C, CP, CM, CPM) showed significantly lower alkaline phosphatase activity compared to the initial soil (LSD, p < 0.05) (Figure 2(3A)). Meanwhile, in the TPH-polluted soil, only the control treatment (CH) exhibited significantly lower enzyme activity at the end of the remediation process (Figure 2(3B)). The treatment with GTC-GVT/2021 inoculum showed no impact on alkaline phosphatase activity compared to the initial soil (LSD, p > 0.05). The most significant increase in alkaline phosphatase activity (1.56 times) was observed when L. corniculatus was cultivated together with GTC-GVT/2021 inoculum. A similar effect of 1.48 times increase was observed when L. corniculatus was grown alone (CHP), and no influence on alkaline phosphatase activity was detected when only the inoculum (CHM) was used. In addition, a strong negative correlation between residual TPH soil concentration and soil alkaline phosphatase activity (r = −0.71, p < 0.05) was found.
While the changes in the acid phosphatase enzyme activity in the uncontaminated soil were almost the same as those of the alkaline phosphatase, there were noticeable differences in the TPH-contaminated soil treatments. During the treatment of TPH-contaminated soil, acid phosphatase activity was significantly increased compared to the initial activity. In CH, CHP, and CHM treatments, acid phosphatase activity has increased by 31.56–57.90%, with no significant difference in applied treatment (Figure 2(4B)). The most substantial positive effect on acid phosphatase activity was recorded in the CHPM treatment (66.0%).

3.3. Soil Microbial Community Substrate Utilisation Profile (CLPP)

The Biolog EcoPlate tool was used to analyse the soil microbial carbon substrate utilisation profile (CLPP) after different soil treatments and without treatments in the initial soil. The calculated average well-colour development (AWCD) values for 96 h of incubation time showed the typical sigmoid curve pattern, indicating that the microbial communities in the soil treatments containing GTC-GVT/2021 inoculum and L. corniculatus (CP, CPM, CHP, CHPM) had a more substantial metabolic potential to utilise different carbon sources compared to those from the initial soils (C initial, CH initial) before treatments (LSD, p < 0.05) (Figure 3).
The lowest AWCD was recorded in both contaminated and uncontaminated initial soils (C initial and CH initial) before treatments, and there was no significant difference between these treatments AWCD at the end of the 96 h EcoPlate incubation. Unexpectedly, 20.29% higher microbial catabolic activity was recorded in TPH-contaminated soil in the presence of GTC-GVT/2021 inoculum + L. corniculatus (CHPM) compared to the same treatment in uncontaminated soil (CPM). In general, the microbial activity increased in the order as follows: C initial < CH initial < CP < CPM < CHP < CHPM.

3.4. Plant Biomass Production

The growth of L. corniculatus was suppressed in TPH-contaminated soil, and the impact on the root growth was more detrimental, as shown by the calculated root/shoot ratio (Figure 4C). GTC-GVT/2021 microorganism inoculum application had a positive effect on plant growth both in uncontaminated and contaminated soil, although this stimulatory effect was more pronounced in uncontaminated soil and in the case of root biomass production. (Figure 4). The GTC-GVT/2021 inoculum led to a 33.30% increase in shoot weight in the CPM treatment (LSD, p < 0.05) and 32.0% in the CHPM treatment. The plant root mass data analysis showed similar results (Figure 4B). The GTC-GVT/2021 inoculum significantly increased root mass in unpolluted soil (CPM) by 69.65% and in TPH-contaminated soil (CHPM) by 36.28% compared to treatments without this additive (CP) and (CHP), respectively (LSD, p < 0.05). Plant root and shoot dry weights significantly inversely correlated with residual TPH soil concentration (root: r = −0.78, p < 0.05, shoot: r = −0.76, p < 0.05). The calculated root/shoot ratio indicated that the root biomass of L. corniculatus was more sensitive to soil contamination with petroleum products, though this adverse effect was alleviated by the application of GTC-GVT/2021 inoculum, which has a more pronounced positive effect on root growth (Figure 4C). In particular, the root/shoot ratio increased by 29.70% in the CPM uncontaminated soil treatment compared to the CP treatment without the inoculum. In contaminated soil, the positive effect was less pronounced, showing only a 4.54% increase in CHPM treatment compared to the CHP.

3.5. The Changes in Soil Nutrients and Water-Soluble Phenols

In the uncontaminated soil treatment group, only CPM treatment had a significant positive influence on the NH4+ concentration increase (31.02%) compared to the initial level before treatment (LSD, p < 0.05) (Figure 5(1A)). All the remaining treatments (C, CP, CM) led to a statistically significant decrease in NH4+ compared with the initial concentration before the experiment. The key factor of the NH4+ amount increase during TPH-contaminated soil bioremediation was the application of L. corniculatus; only in the treatments with plants (CHP, CHPM) were significant positive changes in soil NH4+ concentration observed: 13.96% and 7.20%, respectively (Figure 5(1B)). The GTC-GVT/2021 inoculum CHM and CH treatments significantly lowered the amount of NH4+, and the same tendency was observed in uncontaminated soil treatments (C, CM). The single application of GTC-GVT/2021 inoculum had no significant influence on final soil NH4+ concentration compared with the C and CH treatments (LSD, p > 0.05), while the combination of phytoremediation with L. corniculatus and GTC-GVT/2021 inoculum resulted in higher final NH4+ soil concentration compared to unplanted and uninoculated soil treatments.
Soil NO3− level was significantly lower in contaminated soil than in uncontaminated soil. Soil NO3− concentrations decreased during the soil treatment with plants, GTC-GVT/2021 inoculum, and a combination of plants and GTC-GVT/2021 inoculum, and this decrease was observed for both uncontaminated and contaminated soil (Figure 5(2)). The biggest significant drop (LSD, p < 0.05) was measured in C and CP treatments: 17.92% and 13.04%, respectively. On the contrary, during the bioremediation of TPH-contaminated soil, it was observed that the CH treatment and the presence of L. corniculatus (CHP) helped maintain the nitrate concentration close to the initial level (Figure 5(2B)). The most significant decrease in nitrate content was observed when the GTC-GVT/2021 inoculum (CHM treatment) was present, with a reduction of 86.31%. Cultivating L. corniculatus in TPH-contaminated soil (CHPM) with the inoculum helped maintain a slightly notable level of NO3− in the soil, with a decrease of 65.24%.
The GTC-GVT/2021 inoculum remarkably enriched the unpolluted soil with inorganic phosphorus (Figure 5(3A)). The changes in inorganic P amount in the soil in the CM treatment was 6.72 times higher and in the treatment with GTC-GVT/2021 inoculum and L. corniculatus (CPM) was 8.43 times higher compared to the initial value (LSD, p < 0.05). Meanwhile, in the TPH-contaminated soil (Figure 5(3B)), the GTC-GVT/2021 inoculum had no positive effect on inorganic P concentration, with the CHM treatment resulting in the most significant reduction in inorganic P content among all treatments and initial value (LSD, p < 0.05). The remaining treatments (CH, CHP, CHPM) led to a somewhat lower amount of inorganic P compared to the initial level, but there were no significant differences between them (LSD, p > 0.05).
The most significant increase in water-soluble phenols during the soil treatment was recorded in the treatments where L. corniculatus was grown (Figure 5(4A,B)) in uncontaminated (CP, CPM) and TPH-contaminated soil (CHP, CHPM). The rise in water-soluble phenols was much more significant in TPH-contaminated soil, reaching a level 5.39 times higher in the CHP treatment compared to the initial soil (LSD, p < 0.05). In unpolluted soil, L. corniculatus (CP treatment) has increased soluble phenols by 38.09% compared to the initial level. The control treatments (C and CH) showed results slightly below the initial levels. The most significant decrease was observed in the treatment with GTC-GVT/2021 inoculum (CM and CHM) (36.94% and 56.28%, respectively).

4. Discussion

4.1. TPH Bioremediation

Bioremediation is a crucial process for managing and mitigating the impacts of petroleum contamination in historically contaminated sites, contributing to environmental protection and sustainability [41]. Biological treatment of TPH in soil is advantageous over chemical or physical treatment methods. TPH can be completely broken down into environmentally harmless by-products such as CO2, H2O, NH4, and biomass [42,43,44]. At the same time, improvements in soil physicochemical and biological properties leading to soil health recovery could be achieved. Many different strains of microorganisms, including Bacillus, Clostridium, Pseudomonas, Rhodococcus, Mycobacterium, and Micrococcus, are capable of decomposing TPH and utilising it as a source of carbon and energy [45,46]. Many types of microorganisms, such as bacteria, yeast, and fungi, decompose different types of petroleum hydrocarbons, including alkanes, alkenes, and long- and short-chain hydrocarbons. The specific type of hydrocarbon that a particular strain can degrade depends on the metabolic capabilities of that strain [47,48,49]. Different microorganisms thrive under different environmental conditions. Having a diverse inoculum ensures that active organisms are always present, regardless of the environmental conditions. A wide consortium of organisms can create synergistic interactions, where one species’ metabolic activities can enhance another’s, resulting in improved petroleum hydrocarbon biodegradation [19,50].
This study implemented a broad-spectrum consortium (GTC-GVT/2021) comprising all the main groups of microorganisms resulting in significantly enhanced degradation of TPH in contaminated soil compared to natural attenuation without inoculation. Furthermore, when the inoculum was combined with the legume L. corniculatus, a synergistic effect on the TPH removal from the soil was observed mainly through a positive effect on L. corniculatus growth (Figure 4). Overall, during the 90-day biological treatment period, the TPH concentration decreased by 76.93%, i.e., applied techniques have met the threshold values of TPH in the soil [51]. The most frequently reported inoculums for TPH degradation consist of various species of bacteria. Napp et al. (2022) [52], received promising results using three Pseudomonas and Bacillus sp. strains, with an 85% reduction in diesel oil concentration after 60 days. Bidja Abena et al. (2019) [53] reported the effectiveness of a bacterial consortium comprising five strains, which degraded more than 65.0% of crude oil after 40 days of incubation in contaminated soil. Chai et al. (2023) [54] reported that the implementation of an inoculum containing three bacterial strains led to a 51.6% decrease in crude oil concentration in the soil after 42 days. Notably, many authors have observed that petroleum products break down faster at the initial stages of treatment, with the decomposition process slowing down over time. The present study also obtained similar results, with 56.95% of total petroleum hydrocarbons (TPHs) being degraded in the first 45 days of treatment with GTC-GVT/2021 inoculum plus L. corniculatus and only 19.98% of TPH being degraded in the remaining 45 days (Figure 1). This non-linear TPH degradation could be attributed to the rapid consumption of n-alkanes and naphthenic hydrocarbons with fewer carbon atoms at the beginning of the remediation process, followed by the degradation of refractory aromatic hydrocarbons by the microorganisms [55,56]. Additionally, the accumulation of TPH intermediate metabolites, such as aldehydes, ketones, and fatty acids, along with the metabolites produced by microorganisms, may have altered the soil environment, affecting the microorganisms involved in TPH degradation and resulting in a slower degradation rate [57].

4.2. Soil Enzymatic Activity and CLPP

Soil enzymes are crucial for the bioremediation of petroleum-contaminated soils, playing key roles in nutrient cycling and hydrocarbon degradation, and can be used as soil health indicators. Monitoring their activities provides insights into soil contamination and remediation effectiveness [58,59]. The soil dehydrogenase activity after the 90-day study was more pronounced in TPH-contaminated soil treatments and was at higher levels in CHP treatment. Soil pollution by petroleum hydrocarbons (PHs) can serve as a carbon source for certain microorganisms. Dehydrogenase, an enzyme found within soil microorganisms, indicates the soil’s biological activity, which is mainly driven by microorganisms [60]. The rise in dehydrogenase activity in this study suggests that the microorganisms accepted PH as a carbon source, as the dehydrogenase activity was more pronounced in TPH-contaminated soil treatments compared to uncontaminated soil treatments. Kaczyńska et al. (2015) [61] discovered that petroleum products like diesel and fuel oil in appropriate concentrations can enhance dehydrogenase activity, thus promoting metabolic processes. However, other petroleum products, especially petrol, can act as dehydrogenase inhibitors, possibly due to specific chemical components or toxicity [62]. The presence of L. corniculatus increased dehydrogenase activity, while during contaminated soil treatment with the GTC-GVT/2021 inoculum alone and the combination of plants and the GTC-GVT/2021 inoculum, dehydrogenase activity also increased but to a lesser extent. This indicates that organic compounds and exudates released into the rhizosphere can enhance dehydrogenase activity in planted soils, stimulating microbial activity [63]. Additionally, introducing petroleum hydrocarbon-oxidising microorganisms ensures a sufficient species presence for TPH degradation [64].
Similar trends were also observed for soil urease activity, showing that contaminated soil treatments with L. corniculatus (CHP), inoculum GTC-GVT/2021 (CHM), and the combination of plants and inoculum GTC-GVT/2021 (CHPM) resulted in the increase in urease activity. Our results also indicate that the urease activity in petroleum hydrocarbon-polluted soil samples was significantly higher than in non-polluted soil samples. Efsun et al. (2021) [65] also found that urease activity was significantly higher in soil contaminated with 5% crude oil compared to unpolluted soil. Gospodarek et al. (2021) [66], on the contrary, noted a 50% decrease in urease activity due to the addition of petroleum products compared to the control soil. Soil urease activity is a good indicator of the mineralisation potential of organic nitrogen compounds in soil, and the increase in this enzymatic activity indicates a positive outcome in the bioremediation process, correlating with changes in NH4+ levels in the soil [67].
The analysis of soil phosphatases revealed that in uncontaminated soil, all treatments exhibited lower alkaline and acid phosphatase activity compared to the initial soil. However, in TPH-polluted soil, only the control treatment showed significantly lower alkaline phosphatase activity at the end of the remediation process. The use of GTC-GVT/2021 inoculum had no impact on alkaline phosphatase activity. The most notable increase in alkaline phosphatase activity was observed when L. corniculatus was cultivated with GTC-GVT/2021 inoculum (CHPM) or grown alone (CHP). During the treatment of TPH-contaminated soil, acid phosphatase activity increased significantly in all treatments, with no significant difference among them. Lipińska et al. (2019) [68] also discovered that soil phosphatase activity tends to increase in the presence of petroleum hydrocarbons in soil. Wyszkowska and Kucharski (2010) [69] emphasised that the phosphatase enzyme was more resistant to petroleum hydrocarbon contamination in soil than other enzymes. Phosphatases play a crucial role in enhancing the availability of phosphorus to plants. Effective phosphatase activity ensures optimal plant growth, as phosphorus is often a limiting nutrient [70]. The present study observed a strong positive correlation between L. corniculatus application (CHP and CHPM treatments) and soil alkaline phosphatase activity. In the case of acid phosphatase activity, no significant correlation was found between plant growth and an increase in enzymatic activity. Our results suggest that when L. corniculatus is exposed to low-phosphorus stress, it activates multiple mechanisms to improve phosphorus absorption and utilisation. One of these mechanisms involves increasing soil alkaline phosphatase activity [71,72].
The soil community carbon substrate utilisation profile (CLPP) analysis of TPH-contaminated and uncontaminated soil indicated differences in soil metabolic activity between treatments at the end of the bioremediation experiment. There was a significant increase in microbial activity, as indicated by the average well-colour development (AWCD), in contaminated soil compared to uncontaminated soil. This increase was highest in treatments with the GTC-GVT/2021 inoculum and L. corniculatus. The microbial communities in the soil treatments containing the GTC-GVT/2021 inoculum and L. corniculatus (CP, CPM, CHP, CHPM) demonstrated a greater metabolic potential to utilise different carbon sources compared to those in the initial soils (C initial and CH initial) before the treatments. It is evident that diverse microbial strains incorporated into the soil bring complementary metabolic capabilities. Additionally, when plants are present, they release root exudates, which serve as carbon sources for soil microbes. These exudates can also be a reason for an increase in AWCD, indicating heightened microbial metabolic activity [73]. Other researchers have also found a positive correlation between additional microorganism inoculation and AWSD improvement. Alisi et al. (2009) [74] reported an increase in AWCD in soil contaminated with diesel oil six weeks after the inoculation of a bacterial consortium compared to non-inoculated soil. Pacwa-Płociniczak et al. (2016) [75] indicated differences in the soil metabolic activity between inoculated and non-inoculated petroleum-polluted soils after the bioaugmentation process, with the AWCD being significantly higher in inoculated treatments.

4.3. Plant Biomass Production

Although L. corniculatus enhanced TPH degradation, the growth of L. corniculatus was inhibited in TPH-contaminated soil, with a more evident impact on root growth. The calculated root/shoot ratio showed that the root biomass of L. corniculatus was more sensitive to soil contamination with TPH than above-ground biomass. However, the adverse effects were mitigated by applying the GTC-GVT/2021 inoculum, which notably positively affected root growth. Plant biomass production is a crucial indicator for assessing the effectiveness of plant species in soil petroleum hydrocarbon phytoremediation. When specific plant species can thrive in a polluted environment, accumulating both above-ground and root biomass, they become valuable candidates for pollutant removal. Robust growth and efficient pollutant uptake make such species suitable for phytoremediation efforts [76,77]. Therefore, various techniques are used to stimulate plant growth during phytoremediation. In this study, the inoculum GTC-GVT/2021 has been shown to be effective in the stimulation of L. corniculatus growth both in uncontaminated and contaminated soil (Figure 4). However, the effect was plant part dependent: shoot biomass was stimulated up to 33%, while root biomass was enhanced by 69.65% in uncontaminated soil and by 36.28% in TPH-contaminated soil. Positive microorganism inoculum effects on plant growth could be driven by different mechanisms and were shown in other remediation studies. First of all, microorganisms can act like plant growth promoters in phytoremediation. Sun et al. (2024) [78] highlight the importance of microorganisms and plant roots’ interaction in the rhizosphere. These interactions can enhance nutrient uptake, promote root growth, and improve overall plant health, causing an increase in total biomass. In addition, microorganisms like bacteria, fungi, and yeasts are essential for breaking down TPH in contaminated soil. Their metabolic processes lead to the breakdown of pollutants, reducing their harmful effects on plants. As a result, plants experience less stress and can allocate more energy to growth and biomass production. Since successful phytoremediation involves a comprehensive approach, considering both microbial activity and plant health leads to increased TPH pollution removal rates [79,80]. Generally, an increase in plant biomass corresponds to higher TPH removal rates. There was a strong negative correlation between residual TPH soil concentration and L. corniculatus root and shoot dry weight. Wei et al. (2019) [81] similarly found a significant correlation between biomass and TPH degradation rate. Zuzolo et al. (2021) [82] reported that Festuca arundinacea plants exhibited increased root biomass and improved hydrocarbon degradation in the presence of endophytic fungi, highlighting the importance of the combined benefits of plant-microorganism interactions.

4.4. Soil Nutrients and Water-Soluble Phenols

The significant advantage of using legumes in phytoremediation is the potential to enhance depleted soil with nutrients, particularly nitrogen. When considering phytoremediation goals in the context of ES soil strategy, phytoremediation aligns with ES soil strategies by promoting restoration, microbial interactions, nutrient cycling, eco-friendliness, and cost-effectiveness [7,83,84,85,86]. The most important additional benefit of implementing legumes in phytoremediation is the possibility of enriching depleted soil with nutrients, especially nitrogen. The results prove the benefits of leguminous plants, as significant positive changes in soil NH4+ concentration were observed. Additionally, it was observed that the presence of L. corniculatus (CHP) helped maintain the NO3− concentration close to the initial level, while unplanted treatments, especially those containing microbial inoculum, faced a significant reduction in the amount of this nutrition. As nitrogen is a vital nutrient that promotes the microbial decomposition of TPH in the rhizosphere, the legumes’ properties to enrich the soil are vital for bioremediation success [87,88].
Legumes have the ability to access soil phosphorus sources that are not available to many other plant species. They form specific root structures called proteoid roots, which allow them to isolate carboxylates and phosphatases. These substances are essential for making insoluble phosphorus compounds soluble and bioavailable [89]. Our data showed that L. corniculatus induced alkaline and acid phosphatase activity in TPH-contaminated soil (Figure 2(3,4)). However, there were no significant changes in the amount of inorganic phosphorus in the soil at the end of the experiment. This lack of change may be attributed to the increased phosphorus requirement for TPH biodegradation [90].
Some microorganisms can enhance soil phosphorus availability, reducing the need for excessive fertiliser usage during the remediation and improving plant productivity. Combining the appropriate microbial inoculum with legume plants can enrich the soil with phosphorus [91,92]. The GTC-GVT/2021 inoculum significantly increased the concentration of inorganic phosphorus in unpolluted soil when used alone or in combination with L. corniculatus. However, in TPH-contaminated soil, the GTC-GVT/2021 inoculum did not positively affect inorganic phosphorus concentration. The TPH inhibition of microbial metabolic processes related to the phosphorus cycle or the increased phosphorus need for enhanced TPH biodegradation could be decisive factors for the obtained differences [93].
Plant roots have the ability to release soluble phenols, which are a diverse group of organic compounds, including flavonoids, tannins, and lignins. These phenolic molecules have essential roles in plant–soil interactions. They act as chemical messengers within the plant, regulating transcription, vesicle trafficking, signal transduction, and membrane permeability [94]. Phenolic compounds are also involved in both below-ground and above-ground defence mechanisms. Plants produce them during adverse stress conditions such as drought, heat, pollution, and others [95,96]. These compounds serve as chemo-attractants, promoting the formation of plant-specific microbiota and beneficial microorganism colonisation. They can stimulate a wide range of microorganisms in the rhizosphere, including petroleum hydrocarbons degraders. Consequently, areas with abundant root exudates experience higher microbial biomass and increased contaminant transformation rates [97,98,99]. The positive effect of plants on water-soluble phenol concentrations was also proved in our study, though the effect differed among uncontaminated and contaminated soil (Figure 5(4)). These results are consistent with the observation of an increase in water-soluble phenol concentrations in the presence of plant stress conditions. Soleimani et al. (2010) [100] also found an increase in the concentration of water-soluble phenols during TPH soil phytoremediation by two grass species (Festuca arundinacea Schreb. and Festuca pratensis Huds.). The most significant decrease in water-soluble phenol concentration was measured in the treatment with the GTC-GVT/2021 inoculum (CM and CHM), possibly due to the acceptance of microorganisms as an additional nutrient source, consistently with the changes in AWCD (Figure 3).

5. Conclusions

The GTC-GVT/2021 inoculum significantly enhanced the degradation of total petroleum hydrocarbons (TPHs) in contaminated soil and the recovery of soil health compared to natural attenuation. When combined with L. corniculatus, the synergistic effect on the TPH degradation and soil health recovery occurred. The application of the GTC-GVT/2021 inoculum positively affected plant growth in uncontaminated and contaminated soil, with a more pronounced effect in uncontaminated soil. In uncontaminated soil treatments, dehydrogenase, urease, alkaline, and acid phosphatase activity was less pronounced than in TPH-contaminated soil treatments. In most cases, the joint presence of L. corniculatus plant and the GTC-GVT/2021 inoculum led to a significantly higher soil enzymatic activity. The GTC-GVT/2021 inoculum CHM and CH treatments significantly lowered the amount of NH4+, while the combination of L. corniculatus and the GTC-GVT/2021 inoculum resulted in a higher final NH4+ soil concentration compared to unplanted and uninoculated soil treatments. Cultivating L. corniculatus in TPH-contaminated soil (CHPM) with the inoculum helped maintain a slightly higher NO3− level in the soil than in other treatments. The GTC-GVT/2021 inoculum alone and with L. corniculatus significantly increased the amount of inorganic phosphorus in unpolluted soil; however, in TPH-contaminated soil, no positive effect was observed. Under soil TPH contamination, the concentration of water-soluble phenols in L. corniculatus-planted treatments (CHP and CHPM) increased significantly compared to the initial soil. In general, a combined soil remediation strategy involving leguminous plants and a broad-spectrum microorganism inoculum GTC-GVT/2021 can be used to bioremediate TPH-contaminated soil in an environmentally friendly and sustainable manner without secondary pollution. It also stays in line with EU soil strategy objectives and goals of sustainable development because it is a relatively cheap way to decontaminate soil, increase the amount of nutrients, and restore soil microbiological parameters.

Author Contributions

Conceptualisation, R.M. and J.Ž.; methodology, R.M.; software, J.Ž.; validation, R.M. and J.Ž.; formal analysis, R.M.; investigation, R.M., I.V., A.I.P.-C. and M.K.; resources, R.M. and J.Ž.; data curation, R.M. and I.V.; writing—original draft preparation, R.M.; writing—review and editing, J.Ž.; visualisation, R.M.; supervision, J.Ž.; project administration, J.Ž.; funding acquisition, R.M. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Dataset available upon request from the authors.

Acknowledgments

The authors express their gratitude to the company “GVT LT” for their technical support and knowledge.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Kuppusamy, S.; Maddela, N.R.; Megharaj, M.; Venkateswarlu, K. An overview of total petroleum hydrocarbons. In Total Petroleum Hydrocarbons: Environmental Fate, Toxicity, and Remediation; Springer: Cham, Switzerland, 2020; pp. 1–27. [Google Scholar] [CrossRef]
  2. Eneh, O.C. A review on petroleum: Source, uses, processing, products and the environment. J. Appl. Sci. 2011, 11, 2084–2091. [Google Scholar] [CrossRef]
  3. Colgan, J.D. Oil, domestic politics, and international conflict. Energy Res. Soc. Sci. 2014, 1, 198–205. [Google Scholar] [CrossRef]
  4. Adipah, S. Introduction of petroleum hydrocarbons contaminants and its human effects. J. Environ. Sci. Public Health 2019, 3, 1–9. [Google Scholar] [CrossRef]
  5. Gainer, A.; Bresee, K.; Hogan, N.; Siciliano, S.D. Advancing soil ecological risk assessments for petroleum hydrocarbon contaminated soils in Canada: Persistence, organic carbon normalization and relevance of species assemblages. Sci. Total Environ. 2019, 668, 400–410. [Google Scholar] [CrossRef] [PubMed]
  6. Khan, M.A.I.; Biswas, B.; Smith, E.; Naidu, R.; Megharaj, M. Toxicity assessment of fresh and weathered petroleum hydrocarbons in contaminated soil-a review. Chemosphere 2018, 212, 755–767. [Google Scholar] [CrossRef]
  7. Daâssi, D.; Qabil Almaghribi, F. Petroleum-contaminated soil: Environmental occurrence and remediation strategies. 3 Biotech. 2022, 12, 139. [Google Scholar] [CrossRef]
  8. Koul, B.; Taak, P. Ex situ Soil Remediation Strategies. In Biotechnological Strategies for Effective Remediation of Polluted Soils; Springer: Singapore, 2018. [Google Scholar] [CrossRef]
  9. Pavel, L.V.; Gavrilescu, M. Overview of ex situ decontamination techniques for soil cleanup. Environ. Eng. Manag. J. 2008, 7, 815–834. [Google Scholar] [CrossRef]
  10. Ossai, I.C.; Ahmed, A.; Hassan, A.; Hamid, F.S. Remediation of soil and water contaminated with petroleum hydrocarbon: A review. Environ. Technol. Innov. 2020, 17, 100526. [Google Scholar] [CrossRef]
  11. Alori, E.T.; Gabasawa, A.I.; Elenwo, C.E.; Agbeyegbe, O.O. Bioremediation techniques as affected by limiting factors in soil environment. Front. Soil Sci. 2022, 2, 937186. [Google Scholar] [CrossRef]
  12. Asghar, H.N.; Rafique, H.M.; Zahir, Z.A.; Khan, M.Y.; Akhtar, M.J.; Naveed, M.; Saleem, M. Petroleum hydrocarbons-contaminated soils: Remediation approaches. In Soil Science: Agricultural and Environmental Prospectives; Hakeem, K., Akhtar, J., Sabir, M., Eds.; Springer: Cham, Switzerland, 2016; pp. 105–129. [Google Scholar] [CrossRef]
  13. Sui, X.; Wang, X.; Li, Y.; Ji, H. Remediation of petroleum-contaminated soils with microbial and microbial combined methods: Advances, mechanisms, and challenges. Sustainability 2021, 13, 9267. [Google Scholar] [CrossRef]
  14. Ruley, J.A.; Amoding, A.; Tumuhairwe, J.B.; Basamba, T.A. Rhizoremediation of petroleum hydrocarbon–contaminated soils: A systematic review of mutualism between phytoremediation species and soil living microorganisms. In Phytoremediation; Bhat, R.A., Policarpo, F.M., Tonelli, D., Hakeem, K., Eds.; Academic Press: Cambridge, UK, 2022; pp. 263–296. [Google Scholar] [CrossRef]
  15. Baburam, C.; Mitema, A.; Tsekoa, T.; Feto, N.A. Bacillus species and Their Invaluable Roles in Petroleum hydrocarbon Bioremediation. In Bacilli in Agrobiotechnology. Bacilli in Climate Resilient Agriculture and Bioprospecting; Islam, M.T., Rahman, M., Pandey, P., Eds.; Springer: Cham, Switzerland, 2022; pp. 101–126. [Google Scholar] [CrossRef]
  16. Hasan, I.F. Role of Filamentous Fungi to Remove Petroleum Hydrocarbons from the Environment. In Microbial Action on Hydrocarbons; Kumar, V., Kumar, M., Prasad, R., Eds.; Springer: Singapore, 2018; pp. 567–580. [Google Scholar] [CrossRef]
  17. Wang, M.; Zhou, M.; Li, H.; Cao, Z.; Ding, M.; Yuan, Y. Construction of yeast microbial consortia for petroleum hydrocarbons degradation. Front. Bioeng. Biotechnol. 2024, 12, 1408361. [Google Scholar] [CrossRef] [PubMed]
  18. Tyagi, M.; da Fonseca, M.M.R.; de Carvalho, C.C.C.R. Bioaugmentation and biostimulation strategies to improve the effectiveness of bioremediation processes. Biodegradation 2011, 22, 231–241. [Google Scholar] [CrossRef] [PubMed]
  19. Patowary, K.; Patowary, R.; Kalita, M.C.; Deka, S. Development of an efficient bacterial consortium for the potential remediation of hydrocarbons from contaminated sites. Front. Microbiol. 2016, 7, 1092. [Google Scholar] [CrossRef] [PubMed]
  20. Mekonnen, B.A.; Aragaw, T.A.; Genet, M.B. Bioremediation of petroleum hydrocarbon contaminated soil: A review on principles, degradation mechanisms, and advancements. Front. Environ. Sci. 2024, 12, 1354422. [Google Scholar] [CrossRef]
  21. Canon, F.; Nidelet, T.; Guédon, E.; Thierry, A.; Gagnaire, V. Understanding the Mechanisms of Positive Microbial Interactions That Benefit Lactic Acid Bacteria Co-cultures. Front. Microbiol. 2020, 11, 2088. [Google Scholar] [CrossRef]
  22. Sales da Silva, I.G.; Gomes de Almeida, F.C.; Padilha da Rocha e Silva, N.M.; Casazza, A.A.; Converti, A.; Asfora Sarubbo, L. Soil bioremediation: Overview of technologies and trends. Energies 2020, 13, 4664. [Google Scholar] [CrossRef]
  23. Pawlik, M.; Cania, B.; Thijs, S.; Vangronsveld, J.; Piotrowska-Seget, Z. Hydrocarbon degradation potential and plant growth-promoting activity of culturable endophytic bacteria of Lotus corniculatus and Oenothera biennis from a long-term polluted site. Environ. Sci. Pollut. Res. Int. 2017, 24, 19640–19652. [Google Scholar] [CrossRef]
  24. Pawluśkiewicz, B.; Gnatowski, T.; Janicka, M. The influence of soil contamination with diesel oil on germination dynamics and seedling development of selected species of the Fabaceae family. J. Ecol. Eng. 2020, 21, 210–218. [Google Scholar] [CrossRef]
  25. Flores-Naveda, A.; Alvarez-Vazquez, P.; Mendoza-Pedroza, S.I.; Ventura-Rios, J.; Garcia-Lopez, J.I.; Camposeco-Montejo, N. Forage Yield Lotus (Lotus corniculatus L.) by varying the criterion at the time of harvest. Fresenius Environ. Bull. 2022, 31, 7615–7622. [Google Scholar]
  26. Stevanovic, P.; Vuckovic, S.; Popovic, V.; Ikanovic, J.; Zivanovic, L.; Tabakovic, M.; Lakic, Z. Influence of the mineral fertilization at morphological and productive characteristics of the Lotus corniculatus on pseudogley. Wulfenia 2015, 22, 190–204. [Google Scholar] [CrossRef]
  27. Meištininkas, R.; Vaškevičienė, I.; Dikšaitytė, A.; Pedišius, N.; Žaltauskaitė, J. Potential of Eight Species of Legumes for Heavy Fuel Oil-Contaminated Soil Phytoremediation. Sustainability 2023, 15, 4281. [Google Scholar] [CrossRef]
  28. ISO 16703:2004; ISO 2004 Soil Quality—Determination of Content of in the Range C10—C40 by Gas Chromatography. International Organization for Standardization: Geneva, Switzerland, 2004.
  29. Hood-Nowotny, R.; Umana, N.H.N.; Inselbacher, E.; Oswald-Lachouani, P.; Wanek, W. Alternative Methods for Measuring Inorganic, Organic, and Total Dissolved Nitrogen in Soil. Soil Sci. Soc. Am. J. 2010, 74, 1018–1027. [Google Scholar] [CrossRef]
  30. Fernández, J.A.; Niell, F.X.; Lucena, J. A rapid and sensitive automated determination of phosphate in natural waters 1. Limnol. Oceanogr. 1985, 30, 227–230. [Google Scholar] [CrossRef]
  31. Kandeler, E.; Gerber, H. Short-term assay of soil urease activity using colorimetric determination of ammonium. Biol. Fertil. Soils 1988, 6, 68–72. [Google Scholar] [CrossRef]
  32. Cheema, S.A.; Khan, M.I.; Tang, X.; Zhang, C.; Shen, C.; Malik, Z.; Chen, Y. Enhancement of phenanthrene and pyrene degradation in rhizosphere of tall fescue (Festuca arundinacea). J. Hazard. Mater. 2009, 166, 1226–1231. [Google Scholar] [CrossRef]
  33. Veas-Arancibia, C. Spectroscopy and Photochromism of Triphenylformazan and Its Derivatives. Ph.D. Thesis, Louisiana State University and Agricultural & Mechanical College, Baton Rouge, LA, USA, 1986. [Google Scholar]
  34. Alef, K.; Nannipieri, P. Methods in Applied Soil Microbiology and Biochemistry; Academic Press: London, UK, 1995; pp. 1–576. [Google Scholar] [CrossRef]
  35. Bingham, E.W.; Garver, K. Purification and properties of an acid phosphatase from lactating bovine mammary gland. J. Dairy Sci. 1990, 73, 964–969. [Google Scholar] [CrossRef]
  36. Zhang, H.M.; Zhang, G.C.; Wang, Y.Q. The Interaction of Chromium(VI) with Urease in Solution. Biol. Trace Elem. Res. 2011, 141, 53–64. [Google Scholar] [CrossRef] [PubMed]
  37. Bonmati, M.; Pujola, M.; Sana, J.; Soliva, M.; Felipo, M.T.; Garau, M.; Ceccanti, B.; Nannipieri, P. Chemical properties, populations of nitrite oxidizers, urease and phosphatase activities in sewage sludge-amended soils. Plant Soil 1985, 84, 79–91. [Google Scholar] [CrossRef]
  38. Rutgers, M.; Wouterse, M.; Drost, S.M.; Breure, A.M.; Mulder, C.; Stone, D.; Creamer, R.E.; Winding, A.; Bloem, J. Monitoring soil bacteria with community-level physiological profiles using Biolog™ ECO-plates in the Netherlands and Europe. Appl. Soil Ecol. 2016, 97, 23–35. [Google Scholar] [CrossRef]
  39. Urbaniak, M.; Mierzejewska-Sinner, E.; Bednarek, A.; Krauze, K.; Włodarczyk-Marciniak, R. Microbial response to Nature-Based Solutions in urban soils: A comprehensive analysis using Biolog® EcoPlates™. Sci. Total Environ. 2024, 928, 172360. [Google Scholar] [CrossRef]
  40. Gryta, A.; Frąc, M.; Oszust, K. The application of the Biolog EcoPlate approach in ecotoxicological evaluation of dairy sewage sludge. Appl. Biochem. Biotechnol. 2014, 174, 1434–1443. [Google Scholar] [CrossRef] [PubMed]
  41. Zainab, R.; Hasnain, M.; Ali, F.; Dias, D.A.; El-Keblawy, A.; Abideen, Z. Exploring the bioremediation capability of petroleum-contaminated soils for enhanced environmental sustainability and minimization of ecotoxicological concerns. Environ. Sci. Pollut. Res. Int. 2023, 30, 104933–104957. [Google Scholar] [CrossRef] [PubMed]
  42. Kumari, B.; Singh, G.K.; Sinam, G.; Singh, D.P. Microbial Remediation of Crude Oil-Contaminated Sites. In Environmental Concerns and Sustainable Development; Shukla, V., Kumar, N., Eds.; Springer: Singapore, 2020; pp. 333–351. [Google Scholar] [CrossRef]
  43. Yang, Y.; Zhang, Z.W.; Liu, R.X.; Ju, H.-Y.; Bian, X.-K.; Zhang, W.-Z.; Zhang, C.-B.; Yang, T.; Guo, B.; Xiao, C.-L.; et al. Research progress in bioremediation of petroleum pollution. Environ. Sci. Pollut. Res. 2021, 28, 46877–46893. [Google Scholar] [CrossRef]
  44. Salari, M.; Rahmanian, V.; Hashemi, S.A.; Chiang, W.-H.; Lai, C.W.; Mousavi, S.M.; Gholami, A. Bioremediation treatment of polyaromatic hydrocarbons for environmental sustainability. Water 2022, 14, 3980. [Google Scholar] [CrossRef]
  45. Mousavi, S.M.; Zarei, M.; Hashemi, S.A.; Ramakrishna, S.; Chiang, W.-H.; Lai, C.W.; Gholami, A. Gold nanostars-diagnosis, bioimaging and biomedical applications. Drug Metab. Rev. 2020, 52, 299–318. [Google Scholar] [CrossRef]
  46. Fathepure, B.Z. Recent studies in microbial degradation of petroleum hydrocarbons in hypersaline environments. Front. Microbiol. 2014, 5, 173. [Google Scholar] [CrossRef]
  47. Xu, X.; Liu, W.; Tian, S.; Wang, W.; Qi, Q.; Jiang, P.; Gao, X.; Li, F.; Li, H.; Yu, H. Petroleum hydrocarbon-degrading bacteria for the remediation of oil pollution under aerobic conditions: A perspective analysis. Front. Microbiol. 2018, 9, 2885. [Google Scholar] [CrossRef]
  48. Zhang, M.; Chen, Q.; Gong, Z. Microbial remediation of petroleum-contaminated soil focused on the mechanism and microbial response: A review. Environ. Sci. Pollut. Res. Int. 2024, 31, 33325–33346. [Google Scholar] [CrossRef]
  49. Mahmoud, G.A.E.; Bagy, M.M.K. Microbial Degradation of Petroleum Hydrocarbons. In Microbial Action on Hydrocarbons; Kumar, V., Kumar, M., Prasad, R., Eds.; Springer: Singapore, 2018; pp. 299–320. [Google Scholar] [CrossRef]
  50. Wang, S.; Wang, D.; Yu, Z.; Dong, X.; Liu, S.; Cui, H.; Sun, B. Advances in research on petroleum biodegradability in soil. Environ. Sci. Process. Impacts 2021, 23, 9–27. [Google Scholar] [CrossRef]
  51. LAND 9-2009. Environmental Protection Requirements for the Management of Territories Contaminated by Petroleum Products. Available online: https://e-seimas.lrs.lt/portal/legalAct/lt/TAD/TAIS.359066/asr (accessed on 1 June 2024).
  52. Napp, A.P.; Allebrandt, S.R.; Pereira, J.E.S.; Streit, R.S.A.; Bücker, F.; Mitidieri, S.; Schrank, A.; Bento, F.M.; Vainstein, M.H. Scale-up treatment of petroleum hydrocarbon-contaminated soil using a defined microbial consortium. Int. J. Environ. Sci. Technol. 2022, 19, 6023–6032. [Google Scholar] [CrossRef]
  53. Bidja Abena, M.T.; Sodbaatar, N.; Li, T.; Damdinsuren, N.; Choidash, B.; Zhong, W. Crude oil biodegradation by newly isolated bacterial strains and their consortium under soil microcosm experiment. Appl. Biochem. Biotechnol. 2019, 189, 1223–1244. [Google Scholar] [CrossRef] [PubMed]
  54. Chai, X.; Wang, M.; Fu, X.; Zhang, W.; Huang, Y.; Germaine, K.J.; Wang, J. Shift of combined ecotoxicity index in petroleum polluted soils during a bacterial remediation. Front. Environ. Sci. 2023, 11, 1141562. [Google Scholar] [CrossRef]
  55. Chaineau, C.H.; Morel, J.L.; Oudot, J. Microbial degradation in soil microcosms of fuel oil hydrocarbons from drilling cuttings. Environ. Sci. Technol. 1995, 29, 1615–1621. [Google Scholar] [CrossRef] [PubMed]
  56. Langbehn, A.; Steinhart, H. Biodegradation studies of hydrocarbons in soils by analyzing metabolites formed. Chemosphere 1995, 30, 855–868. [Google Scholar] [CrossRef]
  57. Jørgensen, K.S.; Puustinen, J.; Suortti, A.M. Bioremediation of petroleum hydrocarbon-contaminated soil by composting in biopiles. Environ. Pollut. 2000, 107, 245–254. [Google Scholar] [CrossRef] [PubMed]
  58. Ite, A.E.; Ibok, U.J. Role of plants and microbes in bioremediation of petroleum hydrocarbons contaminated soils. Int. J Environ. Bioremediat Biodegrad. 2019, 7, 1–19. [Google Scholar]
  59. Curyło, K.; Telesiński, A. Use of phosphatase and dehydrogenase activities in the assessment of calcium peroxide and citric acid effects in soil contaminated with petrol. Open Life Sci. 2020, 15, 12–20. [Google Scholar] [CrossRef]
  60. Kumar, S.; Chaudhuri, S.; Maiti, S.K. Soil dehydrogenase enzyme activity in natural and mine soil-a review. Middle East J. Sci. Res. 2013, 13, 898–906. [Google Scholar]
  61. Kaczyńska, G.; Borowik, A.; Wyszkowska, J. Soil dehydrogenases as an indicator of contamination of the environment with petroleum products. Water Air Soil Pollut. 2015, 226, 372. [Google Scholar] [CrossRef] [PubMed]
  62. Achuba, F.I.; Okoh, P.N. Effect of petroleum products on soil catalase and dehydrogenase activities. Open J. Soil Sci. 2014, 04, 399–406. [Google Scholar] [CrossRef]
  63. Kaur, J.; Kaur, G. Dehydrogenase activity as a biological indicator of soil health. Chem. Sci. Rev. Lett. 2021, 10, 326–329. [Google Scholar]
  64. Meena, A.; Rao, K.S. Assessment of soil microbial and enzyme activity in the rhizosphere zone under different land use/cover of a semiarid region, India. Ecol. Process. 2021, 10, 16. [Google Scholar] [CrossRef]
  65. Dindar, E.; Şağban, F.O.T.; Başkaya, H.S. Variations of soil enzyme activities in petroleum-hydrocarbon contaminated soil. Int. Biodeterior. Biodegrad. 2015, 105, 268–275. [Google Scholar] [CrossRef]
  66. Gospodarek, J.; Rusin, M.; Barczyk, G.; Nadgórska-Socha, A. The Effect of Petroleum-Derived Substances and Their Bioremediation on Soil Enzymatic Activity and Soil Invertebrates. Agronomy 2021, 11, 80. [Google Scholar] [CrossRef]
  67. Roscoe, R.; Vasconcellos, C.A.; Furtini-Neto, A.E.; Guedes, G.A.; Fernandes, L.A. Urease activity and its relation to soil organic matter, microbial biomass nitrogen and urea-nitrogen assimilation by maize in a Brazilian oxisol under no-tillage and tillage systems. Biol. Fertil. Soils 2000, 32, 52–59. [Google Scholar] [CrossRef]
  68. Lipińska, A.; Kucharski, J.; Wyszkowska, J. Activity of phosphatases in soil contaminated with PAHs. Water Air Soil Pollut. 2019, 230, 298. [Google Scholar] [CrossRef]
  69. Wyszkowska, J.; Kucharski, J. Correlation between the number of cultivable microorganisms and soil contamination with diesel oil. Pol. J. Environ. Stud. 2010, 14, 347–356. [Google Scholar]
  70. Nannipieri, P.; Giagnoni, L.; Landi, L.; Renella, G. Role of phosphatase enzymes in soil. In Phosphorus in Action. Soil Biology; Bünemann, E., Oberson, A., Frossard, E., Eds.; Springer: Berlin/Heidelberg, Germany, 2011; Volume 26, pp. 215–243. [Google Scholar] [CrossRef]
  71. Boschetti, N.G.; Quintero, C.E.; Giuffre, L. Phosphorus fractions of soils under Lotus corniculatus as affected by different phosphorus fertilizers. Biol. Fertil. Soils 2009, 45, 379–384. [Google Scholar] [CrossRef]
  72. Zhao, X.; Chen, K.K.; Wang, L.T.; Zhao, L.L.; Wang, P.C. Transcriptome analysis provides insights into the response of Lotus corniculatus roots to low-phosphorus stress. Front. Plant Sci. 2023, 14, 1089380. [Google Scholar] [CrossRef]
  73. Zhong, M.; Yang, C.; Su, L.; Sun, Z.; Xu, J.; Zhang, J.; Li, Q.; Hao, Y.; Ma, H.; Chen, H.; et al. Interactions between plants and bacterial communities for phytoremediation of petroleum-contaminated soil. Environ. Sci. Pollut. Res. Int. 2024, 31, 37564–37573. [Google Scholar] [CrossRef]
  74. Alisi, C.; Musella, R.; Tasso, F.; Ubaldi, C.; Manzo, S.; Cremisini, C.; Sprocati, A.R. Bioremediation of diesel oil in a co-contaminated soil by bioaugmentation with a microbial formula tailored with native strains selected for heavy metals resistance. Sci. Total Environ. 2009, 407, 3024–3032. [Google Scholar] [CrossRef]
  75. Pacwa-Płociniczak, M.; Płaza, G.A.; Piotrowska-Seget, Z. Monitoring the changes in a bacterial community in petroleum-polluted soil bioaugmented with hydrocarbon-degrading strains. Appl. Soil Ecol. 2016, 105, 76–85. [Google Scholar] [CrossRef]
  76. Germaine, K.J.; Byrne, J.; Liu, X.; Keohane, J.; Culhane, J.; Lally, R.D.; Kiwanuka, S.; Ryan, D.; Dowling, D.N. Ecopiling: A combined phytoremediation and passive biopiling system for remediating hydrocarbon impacted soils at field scale. Front. Plant Sci. 2014, 5, 756. [Google Scholar] [CrossRef]
  77. Kaimi, E.; Mukaidani, T.; Tamaki, M. Screening of twelve plant species for phytoremediation of petroleum hydrocarbon-contaminated soil. Plant Prod. Sci. 2007, 10, 211–218. [Google Scholar] [CrossRef]
  78. Sun, W.J.; Li, Q.; Luo, B.Y.; Sun, R.; Ke, C.Y.; Wang, S.C.; Zhang, Q.Z.; Zhang, X.L. Pilot-scale field studies on activated microbial remediation of petroleum-contaminated soil. Environ. Geochem. Health 2024, 46, 243. [Google Scholar] [CrossRef]
  79. Udume, O.A.; Abu, G.O.; Stanley, H.O.; Vincent-Akpu, I.F.; Momoh, Y.; Eze, M.O. Biostimulation of Petroleum-Contaminated Soil Using Organic and Inorganic Amendments. Plants 2023, 12, 431. [Google Scholar] [CrossRef] [PubMed]
  80. Gkorezis, P.; Daghio, M.; Franzetti, A.; Van Hamme, J.D.; Sillen, W.; Vangronsveld, J. The interaction between plants and bacteria in the remediation of petroleum hydrocarbons: An environmental perspective. Front. Microbiol. 2016, 7, 1836. [Google Scholar] [CrossRef]
  81. Wei, Y.; Wang, Y.; Duan, M.; Han, J.; Li, G. Growth tolerance and remediation potential of six plants in oil-polluted soil. J. Soils Sediments 2019, 19, 3773–3785. [Google Scholar] [CrossRef]
  82. Zuzolo, D.; Guarino, C.; Tartaglia, M.; Sciarrillo, R. Plant–soil-microbiota combination for the removal of total petroleum hydrocarbons (TPH): An in-field experiment. Front. Microbiol. 2020, 11, 621581. [Google Scholar] [CrossRef]
  83. Chan-Quijano, J.G.; Cach-Pérez, M.J.; Rodríguez-Robles, U. Phytoremediation of soils contaminated by hydrocarbon. In Phytoremediation. Concepts and Strategies in Plant Sciences; Shmaefsky, B., Ed.; Springer: Cham, Switzerland, 2020; Volume 3, pp. 83–101. [Google Scholar] [CrossRef]
  84. Wojtowicz, K.; Steliga, T.; Kapusta, P. Evaluation of the effectiveness of bioaugmentation-assisted phytoremediation of soils contaminated with petroleum hydrocarbons using Echinacea purpurea. Appl. Sci. 2023, 13, 13077. [Google Scholar] [CrossRef]
  85. European Commission. EU Soil Strategy for 2030. Com 2021, 699 Final. Available online: http://ec.europa.eu/environment/publications/eu-soil-strategy-2030_en (accessed on 10 June 2024).
  86. Panagos, P.; Montanarella, L.; Barbero, M.; Schneegans, A.; Aguglia, L.; Jones, A. Soil priorities in the European Union. Geoderma Reg. 2022, 29, e00510. [Google Scholar] [CrossRef]
  87. Kakraliya, S.K.; Singh, U.; Bohra, A.; Choudhary, K.K.; Kumar, S.; Meena, R.S.; Jat, M.L. Nitrogen and legumes: A meta-analysis. In Legumes for Soil Health and Sustainable Management; Meena, R., Das, A., Yadav, G., Lal, R., Eds.; Springer: Singapore, 2018; pp. 277–314. [Google Scholar] [CrossRef]
  88. Wei, Z.; Wang, J.J.; Gaston, L.A.; Li, J.; Fultz, L.M.; DeLaune, R.D.; Dodla, S.K. Remediation of crude oil-contaminated coastal marsh soil: Integrated effect of biochar, rhamnolipid biosurfactant and nitrogen application. J. Hazard. Mater. 2020, 396, 122595. [Google Scholar] [CrossRef] [PubMed]
  89. Neumann, G.; Massonneau, A.; Langlade, N.; Dinkelaker, B.; Hengeler, C.; Römheld, V.; Martinoia, E. Physiological aspects of cluster root function and development in phosphorus-deficient white lupin (Lupinus albus L.). Ann. Bot. 2000, 85, 909–919. [Google Scholar] [CrossRef]
  90. Stepanova, A.Y.; Gladkov, E.A.; Osipova, E.S.; Gladkova, O.V.; Tereshonok, D.V. Bioremediation of soil from petroleum contamination. Processes 2022, 10, 1224. [Google Scholar] [CrossRef]
  91. Richardson, A.E.; Simpson, R.J. Soil microorganisms mediating phosphorus availability update on microbial phosphorus. Plant Physiol. 2011, 156, 989–996. [Google Scholar] [CrossRef] [PubMed]
  92. Beltran-Medina, I.; Romero-Perdomo, F.; Molano-Chavez, L.; Gutiérrez, A.Y.; Silva, A.M.M.; Estrada-Bonilla, G. Inoculation of phosphate-solubilizing bacteria improves soil phosphorus mobilization and maize productivity. Nutr. Cycl. Agroecosyst. 2023, 126, 21–34. [Google Scholar] [CrossRef]
  93. Kong, L.; Shan, Q.; Lai, Y.; Wang, Y.; Jin, C.; An, C.; Yang, L.; Zhang, Z. Oil contamination drives the transformation of microbial communities and metabolic pathways involved in Phosphorous-cycling in coastal soil. J. Soils Sediments 2024, 24, 2638–2651. [Google Scholar] [CrossRef]
  94. Wagay, N.A.; Lone, R.; Rafiq, S.; Bashir, S.U. Phenolics: A game changer in the life cycle of plants. In Plant Phenolics in Sustainable Agriculture; Lone, R., Shuab, R., Kamili, A., Eds.; Springer: Singapore, 2020. [Google Scholar] [CrossRef]
  95. Kumar, K.; Debnath, P.; Singh, S.; Kumar, N. An overview of plant phenolics and their involvement in abiotic stress tolerance. Stresses 2023, 3, 570–585. [Google Scholar] [CrossRef]
  96. Khanday, A.H.; Badroo, I.A.; Wagay, N.A.; Rafiq, S. Role of phenolic compounds in disease resistance to plants. In Plant Phenolics in Biotic Stress Management; Lone, R., Khan, S., Mohammed Al-Sadi, A., Eds.; Springer: Singapore, 2024. [Google Scholar] [CrossRef]
  97. Wallis, C.M.; Galarneau, E.R.A. Phenolic compound induction in plant-microbe and plant-insect interactions: A meta-analysis. Front. Plant Sci. 2020, 11, 580753. [Google Scholar] [CrossRef]
  98. Chauhan, P.; Sharma, N.; Tapwal, A.; Kumar, A.; Verma, G.S.; Meena, M.; Seth, C.S.; Swapnil, P. Soil Microbiome: Diversity, Benefits and Interactions with Plants. Sustainability 2023, 15, 14643. [Google Scholar] [CrossRef]
  99. Yang, K.M.; Poolpak, T.; Pokethitiyook, P. Rhizodegradation: The plant root exudate and microbial community relationship. In Phytoremediation; Newman, L., Ansari, A.A., Gill, S.S., Naeem, M., Gill, R., Eds.; Springer: Cham, Switzerland, 2023. [Google Scholar] [CrossRef]
  100. Soleimani, M.; Afyuni, M.; Hajabbasi, M.A.; Nourbakhsh, F.; Sabzalian, M.R.; Christensen, J.H. Phytoremediation of an aged petroleum contaminated soil using endophyte infected and non-infected grasses. Chemosphere 2010, 81, 1084–1090. [Google Scholar] [CrossRef] [PubMed]
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Figure 1. TPH concentration dynamics after 45 and 90 days in different soil bioremediation treatments: CH: TPH-contaminated soil; CHP: TPH-contaminated soil planted with L. corniculatus; CHM: TPH-contaminated soil with GTC-GVT/2021 inoculum; CHPM: TPH-contaminated soil planted with L. corniculatus + GTC-GVT/2021 inoculum).
Figure 1. TPH concentration dynamics after 45 and 90 days in different soil bioremediation treatments: CH: TPH-contaminated soil; CHP: TPH-contaminated soil planted with L. corniculatus; CHM: TPH-contaminated soil with GTC-GVT/2021 inoculum; CHPM: TPH-contaminated soil planted with L. corniculatus + GTC-GVT/2021 inoculum).
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Figure 2. The dehydrogenase (1), urease (2), alkaline phosphatase (3), and acid phosphatase (4) activity in the soil after 90 days in different soil bioremediation treatments: C: control unpolluted soil; CP: control unpolluted soil planted with L. corniculatus; CM: control unpolluted soil with GTC-GVT/2021 inoculum; CPM: control unpolluted soil planted with L. corniculatus + GTC-GVT/2021 inoculum; CH: TPH-contaminated soil; CHP: TPH-contaminated soil planted with L. corniculatus; CHM: TPH-contaminated soil with GTC-GVT/2021 inoculum; CHPM: TPH-contaminated soil planted with L. corniculatus + GTC-GVT/2021 inoculum). The dashed lines indicate the initial concentrations. Dissimilar letters designate a statistically significant difference (p < 0.05) among the treatments (LSD test). (A) uncontaminated soil group, (B) TPH-contaminated soil group.
Figure 2. The dehydrogenase (1), urease (2), alkaline phosphatase (3), and acid phosphatase (4) activity in the soil after 90 days in different soil bioremediation treatments: C: control unpolluted soil; CP: control unpolluted soil planted with L. corniculatus; CM: control unpolluted soil with GTC-GVT/2021 inoculum; CPM: control unpolluted soil planted with L. corniculatus + GTC-GVT/2021 inoculum; CH: TPH-contaminated soil; CHP: TPH-contaminated soil planted with L. corniculatus; CHM: TPH-contaminated soil with GTC-GVT/2021 inoculum; CHPM: TPH-contaminated soil planted with L. corniculatus + GTC-GVT/2021 inoculum). The dashed lines indicate the initial concentrations. Dissimilar letters designate a statistically significant difference (p < 0.05) among the treatments (LSD test). (A) uncontaminated soil group, (B) TPH-contaminated soil group.
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Figure 3. Average well-colour development (AWCD) of 31 different carbon sources metabolised substrates in Biolog EcoPlates based on 96 h of soil extract incubation obtained from different soil bioremediation treatments: C: initial unpolluted soil; CP: control unpolluted soil planted with L. corniculatus; CPM: control unpolluted soil planted with L. corniculatus + GTC-GVT/2021 inoculum; CH: initial TPH-contaminated soil; CHP: TPH-contaminated soil planted with L. corniculatus; CHPM: TPH-contaminated soil planted with L. corniculatus + GTC-GVT/2021 inoculum).
Figure 3. Average well-colour development (AWCD) of 31 different carbon sources metabolised substrates in Biolog EcoPlates based on 96 h of soil extract incubation obtained from different soil bioremediation treatments: C: initial unpolluted soil; CP: control unpolluted soil planted with L. corniculatus; CPM: control unpolluted soil planted with L. corniculatus + GTC-GVT/2021 inoculum; CH: initial TPH-contaminated soil; CHP: TPH-contaminated soil planted with L. corniculatus; CHPM: TPH-contaminated soil planted with L. corniculatus + GTC-GVT/2021 inoculum).
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Figure 4. Shoot (A), root (B), dry biomass and root/shoot ratio (C) of L. corniculatus grown in CP, CPM, CHP, and CHPM treatments for 90 days. Letters indicate a significant difference (p < 0.05) between the treatments (LSD test).
Figure 4. Shoot (A), root (B), dry biomass and root/shoot ratio (C) of L. corniculatus grown in CP, CPM, CHP, and CHPM treatments for 90 days. Letters indicate a significant difference (p < 0.05) between the treatments (LSD test).
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Figure 5. The final concentrations of NH4+ (1), (NO3−) (2), inorganic P (3), and water-soluble phenols (4) in the soil after 90 days in different soil bioremediation treatments: C: control unpolluted soil; CP: control unpolluted soil planted with L. corniculatus; CM: control unpolluted soil with GTC-GVT/2021 inoculum; CPM: control unpolluted soil planted with L. corniculatus + GTC-GVT/2021 inoculum; CH: TPH-contaminated soil; CHP: TPH-contaminated soil planted with L. corniculatus; CHM: TPH-contaminated soil with GTC-GVT/2021 inoculum; CHPM: TPH-contaminated soil planted with L. corniculatus + GTC-GVT/2021 inoculum). The dashed lines indicate the initial concentrations. Dissimilar letters designate a statistically significant difference (p < 0.05) among the treatments (LSD test). (A) uncontaminated soil group, (B) TPH-contaminated soil group.
Figure 5. The final concentrations of NH4+ (1), (NO3−) (2), inorganic P (3), and water-soluble phenols (4) in the soil after 90 days in different soil bioremediation treatments: C: control unpolluted soil; CP: control unpolluted soil planted with L. corniculatus; CM: control unpolluted soil with GTC-GVT/2021 inoculum; CPM: control unpolluted soil planted with L. corniculatus + GTC-GVT/2021 inoculum; CH: TPH-contaminated soil; CHP: TPH-contaminated soil planted with L. corniculatus; CHM: TPH-contaminated soil with GTC-GVT/2021 inoculum; CHPM: TPH-contaminated soil planted with L. corniculatus + GTC-GVT/2021 inoculum). The dashed lines indicate the initial concentrations. Dissimilar letters designate a statistically significant difference (p < 0.05) among the treatments (LSD test). (A) uncontaminated soil group, (B) TPH-contaminated soil group.
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Table 1. Main physicochemical soil properties of the uncontaminated and TPH-contaminated soils before treatments (mean ± standard error (SE), n = 4).
Table 1. Main physicochemical soil properties of the uncontaminated and TPH-contaminated soils before treatments (mean ± standard error (SE), n = 4).
Main Soil CharacteristicsUncontaminated SoilTPH-Contaminated Soil
Granulometric compositionsandy loamsandy loam
TPH (total petroleum hydrocarbons) concentration (mg kg−1)06120 ± 49
Soil organic matter (SOM) (%)1.89 ± 0.111.76 ± 0.09
pHKCl6.46 ± 0.086.54 ± 0.03
NO3− (mg kg−1)525.45 ± 23.5149.33 ± 3.59
NH4+ (mg kg−1)3.03 ± 0.052.22 ± 0.06
Inorganic P (mg kg−1)6.03 ± 0.0953.64 ± 0.35
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Meištininkas, R.; Vaškevičienė, I.; Piotrowicz-Cieślak, A.I.; Krupka, M.; Žaltauskaitė, J. Sustainable Recovery of the Health of Soil with Old Petroleum Hydrocarbon Contamination through Individual and Microorganism-Assisted Phytoremediation with Lotus corniculatus. Sustainability 2024, 16, 7484. https://doi.org/10.3390/su16177484

AMA Style

Meištininkas R, Vaškevičienė I, Piotrowicz-Cieślak AI, Krupka M, Žaltauskaitė J. Sustainable Recovery of the Health of Soil with Old Petroleum Hydrocarbon Contamination through Individual and Microorganism-Assisted Phytoremediation with Lotus corniculatus. Sustainability. 2024; 16(17):7484. https://doi.org/10.3390/su16177484

Chicago/Turabian Style

Meištininkas, Rimas, Irena Vaškevičienė, Agnieszka I. Piotrowicz-Cieślak, Magdalena Krupka, and Jūratė Žaltauskaitė. 2024. "Sustainable Recovery of the Health of Soil with Old Petroleum Hydrocarbon Contamination through Individual and Microorganism-Assisted Phytoremediation with Lotus corniculatus" Sustainability 16, no. 17: 7484. https://doi.org/10.3390/su16177484

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