Fermentation, Volume 9, Issue 9 (September 2023) – 83 articles

The continuously increasing energy requirement on one hand and the incessant depletion of non-renewable fossil fuels on the other urge us to focus on alternative renewable energy sources such as biofuels. Biofuels including biodiesel, bioethanol, biobutanol, biohydrogen, etc., are generated from different biological sources, and their waste which stands as the best alternative in the present scenario. Specifically, the utilization of biological wastes as raw materials for the production of biofuels is considered as best waste management practice. To date, most of the biodiesel production research has been carried out with plant, algal, and microbial samples, or their waste. It is a well-known fact that diesel can also be produced from specific oily fish and their waste using different methods. In addition, fish waste constitutes a major quantity compared to other food waste which is a serious concern. Furthermore, the disposal of fish waste shows an impact on both the environment and the economy. Hence, the development of protocols for the efficient production of biodiesel from fish waste is the ultimate goal. However, insufficient knowledge and less effort in the conversion of fish waste to biodiesel impede the achievement of this goal. Therefore, this review intends to summarize the mechanism of biodiesel production from fish waste. Also, various physico-chemical factors involved in biodiesel production from fish waste were discussed. In addition, research on biodiesel generation from various fish wastes or waste fish oil was also emphasized in detail, which will be helpful for commercial practice. Overall, this information will be useful for improvement in biodiesel production from fish waste. Full article

Sauce-flavor Daqu is a saccharifying and fermenting agent for sauce-flavor baijiu. Three kinds of Daqu (White Daqu (WQ), Yellow Daqu (YQ), and Black Daqu (BQ)) with different qualities are formed owing to the stacking fermentation. Maillard reaction is an important factor that causes significant differences among the three kinds of high-temperature Daqu, which is also an important source of flavor substances. However, there is a lack of research on the composition differences of Maillard reaction products in the three types of Daqu. In our study, HS-SPME-GC/MS, Py-GC/MS, and high-throughput sequencing were used to investigate the small molecule volatile Maillard substances, melanoidin (macromolecular Maillard substance) composition, and microbial community of three kinds of Daqu. The results showed that there were significant differences in the composition of Maillard products (furans, pyrazines, and melanoidin structure) between the three kinds of Daqu. The melanoidin was mainly composed of furans, pyrrolopyrazines, phenols, and indoles, the proportions of which were different in the three types of Daqu. BQ contained more Maillard products, making the melanoidin more complex. Kroppenstedtia, Monascus, and Thermoascus were the biomarkers of BQ, which contribute to the Maillard reaction. This study is of great significance to further deepen the understanding of the formation mechanism of BQ. Full article

The green biosynthesis of adipic acid, an important monomer of nylon 6,6, has become a research hotspot. α-Aminoadipate is a key intermediate in the metabolic pathway that converts _L-lysine to produce adipic acid. In addition, metabolic flux analysis has become an important part of metabolic engineering. Many metabolic optimization algorithms have been developed to predict engineering intervention strategies with the aim of improving the production of target chemicals. Here, OptHandle, a new metabolic optimization algorithm, has been developed. And, we use OptHandle to optimize the biosynthesis of α-aminoadipate. Based on the results of OptHandle, an engineered Escherichia coli with a 13-fold higher titer was obtained, and 1.10 ± 0.02 g/L of α-aminoadipate was produced. The efficient synthesis of α-aminoadipate lays a foundation for the green production of adipic acid. Full article

Spent coffee waste is the most common by-product of coffee processing, and it has the potential to be used as a source of organic compounds for ruminant diets. The objective of this study was to evaluate the optimal inclusion level and method for using spent coffee waste (SCW) as a ruminant feed and investigate its effects on rumen fermentation characteristics and methane (CH₄) production. The present in vitro batch culture study was conducted using two different experimental designs. The first experimental design (TRIAL. 1) was performed using a control diet of 500 mg of fresh matter basal diet (60% hay/40% concentrate), with SCW being used as a feed additive at 1%, 10% and 20% of the substrate. The second experimental design was performed using the same control diet, with spent coffee waste replacing either part of the hay (TRIAL. 2) or some of the concentrate mixture (TRIAL. 3) at four different dosages (30:70, 50:50, 70:30 and 100). When SCW was supplemented as a feed additive, there were increases in the production of volatile fatty acids and gas; however, it did not show any suppressive effects on CH₄ production. In contrast, when SCW was included as a replacement for hay or concentrate, there were significant reductions in CH₄ production with increasing levels of SCW inclusion. These reductions in CH₄ production were accompanied by negative effects on nutrient digestibility and total volatile fatty acid production. These findings demonstrate that SCW could potentially be used as a prebiotic feed additive. Additionally, when SCW is used as a replacement for silage at 70:30 and 50:50 dosages appear to be feasible as a substitute for animal feed (hay and concentrate). Full article

The low-temperature environment of the Tibetan Plateau presents a technical challenge to composting. This study screened cold-adapted microbes with strong degradation ability and selected five strains to experimentally test and evaluate composting cattle manure in a natural environment in the plateau region. The results showed that both the control and the treatment groups had a slow temperature rise at the beginning of the composting. However, after the first turning, the temperature rise in the inoculated group accelerated. The inoculation of cold-adapted bacteria increased the OM loss in the compost by 8.6%, decreased the retention of nitrogen of the compost by 3%, and increased the seed germination index (GI) value from 44.4% to 73.9%. Microbial community structure analysis showed that the relative abundance of Psychrobacter was more than 50% at the beginning of the composting in the two experimental groups. The cold-adapted microbial inoculation increased the diversity of the microbial community, i.e., Truepera and Luteimona, and the abundance of specific microorganisms during the thermophilic and maturation stages. This study demonstrates that inoculation of cold-adapted bacteria improves the maturity and efficiency of cattle manure composting in a natural plateau environment. Full article

In this present study, the potential application of DCMFC for the treatment of three different sourced industrial wastewater streams: biorefinery, dairy and mixed streams was investigated. Operating conditions were optimised using the Box Behnken design in response surface methodology (RSM) with three validation experimental runs. The effect of process variables, i.e., HRT (48 h), catholyte dose (0.1 gmol/L) and electrode surface area (three carbon rods argumentation-m²) on the production of electricity as voltage yield (mV), power density (mW/m²), current density (mA/m²), Columbic efficiency (%) CE and Gibbs free energy correlation with the electromotive force of the DCMFC system. Experimental results obtained were a positive response towards the predictive values according to the DoE numerical optimisation sequence. At numerical optimum MFC conditions stated above, validation experimental responses of voltage yield by biorefinery wastewater were 645.2 mV, mixed wastewater was 549 mV, and dairy wastewater was 358 mV maximum yields. The power densities and current densities were attained, for biorefinery, mixed wastewater and dairy wastewater sources respectively as; 62 mW/m², 50 mW/m² and 27.2 mW/m², then current densities of 50 mA/m², 44,008 mA/m² and 18 mA/m². The coulombic efficiencies of 0.34%, 0.75% and 0.22%, respectively, were achieved. The validation of predicted optimum operating conditions was successfully attained, especially through the biorefinery wastewater organic substrate. This article articulates that it is highly imperative to choose the most suitable wastewater source as the viable electron donor towards scaling up and maximising the efficiency of generating electricity in the double chamber microbial fuel cell (DCMFC). Moreover, the findings of the current study demonstrate that the DCMFC can be further upscaled through a series connection in a fed-batch mode of operation using a well-designed and simulated process control system that has been computationally designed and modelled using first order MFC model bioenergy generating models MATLAB Simulink and Simscape electrical software. These findings of the simulations were successful and illustrated that an MFC power output can be successfully stepped to be a viable bio-electrochemical technology for both industrial wastewater (IWW) treatment and simultaneous sustainable power generation. Full article

The present study investigates approaches to enhance bio-butanol production using lignocellulosic feedstock via supplements of metabolism perturbation. Traditionally, bio-butanol has been produced through chemical synthesis in a process known as acetone–butanol–ethanol (ABE) fermentation. Today, biochemical techniques involving bacterial strains capable of producing butanol are used with renewable sources of biomass. In this study, a stepwise approach was tailored for metabolic perturbations to maximize butanol production from pure sugar and lignocellulosic feedstock as a reference model fermentation. In preliminary investigations, impacts of CaCO₃, furfural and methyl red on cell growth, sugar utilization, acid production and butanol production were evaluated in glucose feedstock and xylose feedstock. Following the preliminary investigation, with supplementation of 4 g/L CaCO₃, the concentrations of furan derivatives (75% furfural and 25% HMF) and ZnSO₄ were optimized for maximal butanol production from glucose and xylose feedstocks, respectively. A final experiment of butanol production was concluded using lignocellulosic feedstock hydrolysate normally containing 0.5~1.5 g/L furan derivatives under optimized conditions of 2 mg/L ZnSO₄ and 4 g/L CaCO₃. Under optimized conditions, butanol production exceeded 10 g/L in wheat straw hydrolysate, which was significantly higher than that obtained in the absence of ZnSO₄ and CaCO₃. As compared to the traditional lignocellulosic feedstock post-treatment method, the metabolic perturbations method shows advantages in terms of productivity and economics. Full article

The biological detoxification of lignocellulose hydrolysate is an effective method through which to enhance microbial fermentation efficiency. In this study, an inhibitor-tolerant strain of A. niger (Aspergillus niger) was used for the biological detoxification of corncob hydrolysate. The results showed that A. niger M13 can tolerate a concentration of at least 7.50 ± 0.19 g/L of acetic acid, 1.81 ± 0.13 g/L of furfural, and 1.02 ± 0.10 g/L of HMF (5-Hydroxymethylfurfural). The spores had a higher detoxification efficiency than the mycelial pellets with a detoxification rate of 0.1566 g/L/h, 0.1125 g/L/h, and 0.015 g/L/h for acetic acid, furfural, and HMF, respectively. The cell preferentially consumed furfural, then HMF, before simultaneously degrading acetic acid and glucose. A. niger M13 spores could accumulate small amounts of citric acid directly from undetoxified hydrolysate at a concentration of about 6 g/L. Therefore, A. niger M13 can serve as an excellent biological detoxification strain and a potential citric acid fermenting strain when using undetoxified lignocellulosic hydrolysates. Full article

The aim of this experiment is to investigate the effects of lactic acid bacteria and cellulase on the fermentation quality, chemical composition, aerobic stability and ruminal degradation characteristics of mixed silage prepared with amaranth and rice straw. Lactic acid bacteria and cellulase were used as silage additives, and the four treatments were as follows: control group (CON, no additive), lactic acid bacteria group (LAB, additive amount was 5 mg/kg fresh matter), cellulase group (CEL, 2 mg/kg) and lactic acid bacteria and cellulase group (LBC, additive amount was the same as in the individual treatments). All treatments were ensiled for 60 days. The dry-matter, crude-protein, neutral-detergent-fiber and acid-detergent-fiber ruminal degradability of silage were analyzed utilizing the nylon bag method. Compared with the CON group, the inoculation of lactic acid bacteria and cellulase individually promoted the fermentation of mixed silage to a certain degree. The combined inoculation of mixed silage significantly increased (p < 0.05) the concentrations of lactic acid and dry matter, while it reduced (p < 0.05) the pH and ammonia nitrogen/total nitrogen, harmful microorganism counts and contents of acetic acid, neutral detergent fiber and acid detergent fiber. In addition, the aerobic stability time of the LBC group was lower (p < 0.05) than that of the other groups. The ruminal degradation rate of dry matter, crude protein, neutral detergent fiber and acid detergent fiber in the LBC group was significantly increased (p < 0.05) compared to the CON group. Overall, the addition of the additives mentioned earlier improved the quality of mixed silage composed of amaranth and rice straw, and the best results were obtained by combining the inoculation of lactic acid bacteria and cellulase. Full article

Weevil (Rhynchophorus palmarum) powder, teosinte (Dioon mejiae) and Caesar’s mushroom (Amanita caesarea) flour have bioactive compounds with significant nutritional applications. This paper aimed to examine the influence of weevil, teosinte, and mushroom powders on the protease activity, acid tolerance, bile tolerance, lysozyme tolerance, and gastric juice resistance ability of Lactobacillus acidophilus LA-K. Acid tolerance was determined by adjusting the pH of MRS broth to 2.0 for L. acidophilus incubated under aerobic conditions at 37 °C. Bile tolerance was determined by incorporating 0.3% of oxgall. Protease activity was determined spectrophotometrically at 340 nm. Resistance to 100 mg/L of lysozyme in an electrolyte solution was also determined. All ingredients were incorporated at 2% (w/v), while the control had no added ingredients. Acid and lysozyme tolerance were examined at 0, 30, 60, 90, and 120 min of incubation, whereas bile tolerance was analyzed at 0, 4, and 8 h. Gastric juice tolerance was determined at pH 2, 3, 4, 5, and 7 during 0 and 30 min of incubation, while protease activity was evaluated at 0, 12, and 24 h. Use of weevil flour, and Caesar’s mushroom powder resulted in significantly (p < 0.05) lower counts for bile tolerance, acid tolerance, lysozyme resistance and simulated gastric juice tolerance characteristics. Protease activity increased with the use of teosinte flour. As such, this probiotic bacterium can be used alongside certain novel food sources at 2% concentration in the manufacture of fermented products such as yogurt. Full article

Phycocyanobilin (PCB) is the bioactive chromophore attached to Phycocyanin (PC) that is of special interest for nutraceutical and therapeutic applications. However, the production of PCB from the heterologous host Escherichia coli is still very low. To facilitate subsequent application of PCB, improving its production in microbial hosts is still a challenge to be solved. In this paper, a strategy involving fusion-expression of apo-proteins with signal peptides was adopted to improve PCB production in E. coli. First, we reconstructed the PCB biosynthesis pathway in E. coli and then optimized its culture media. Subsequently, one PC α (CpcA) subunit and one PC β (CpcB) subunit, which can capture free PCB, were introduced and increased the yield of PCB. Finally, CpcA was fused with seven signal peptides to generate recombinant proteins, among which, the signal peptide N20 fused with CpcA protein drastically improved PCB production in E. coli, providing a maximum flask output of 8.47 ± 0.18 mg/L. The results of this study demonstrate that PCB distribution and transporting manners in E. coli could affect the heterologous production efficiency. By fusing apo-proteins with signal peptides, the secretion of phycocyanin was refined and the production of PCB was successfully enhanced by 3.7-fold, compared with the starting strain (1.80 ± 0.12 mg/L). This work provided an alternative method for improving the production of PCB and other phycobilins. Full article

This study investigated the effects of substituting rice straw with cassava in total mixed ration silage on feed intake, digestibility, rumen fermentation, ruminating activity, and energy balance. An energy balance experiment was conducted to determine nutrient and energy utilization in dairy bulls. Four Holstein Friesian (HF) crossbred young bulls (93.19% HF × 6.81% Native Thai; average age of 12.08 ± 0.22 months and body weight of 266 ± 9.80 kg) were used in a 4 × 4 Latin square design with four 28-d periods. The four dietary treatments included substituting cassava with rice straw on a 50, 150, 250, and 350 g/kg dry matter basis. Increasing the amount of cassava in the diet resulted in linearly decreased rumination behaviors and enteric methane emissions (p < 0.05) but a linear increase in feed intake and digestibility, total volatile fatty acid concentration, and propionic acid: acetic acid ratio in the rumen fluid (p < 0.05), thus leading to a greater energy balance status (p < 0.01). Our results indicated that replacing cassava with rice straw from 5% to 35% in the ration of Holstein bulls resulted in a substantial reduction in physically effective fiber and chewing time but improved nutrient and energy supply. The metabolizable energy requirement for the maintenance of crossbred dairy bulls was estimated to be 599.9 kJ/kg metabolic body weight and the efficiency of metabolizable energy used for growth was 0.88. We concluded that cassava is a good energy feed resource for Holstein crossbred bulls in the tropics. Full article

Glycoproteins are involved in various significant biological processes and have critical biological functions in physiology and pathology by regulating biological activities and molecular signaling pathways. The variety of enzymes used in protein glycosylation and the wide range of diversity in the resulting glycoproteins pose a challenging task when attempting to simulate these processes in silico. This study aimed to establish and define the necessary structures to simulate the process of N-glycosylation in silico. In this article, we represent the process of glycosylation in the Golgi structure in an agent-based model with defined movement patterns and reaction rules between the associated proteins and enzymes acting as agents. The Golgi structure is converted into a grid consisting of 150 × 400 patches representing four compartments which contain a specific distribution of the fundamental enzymes contributing to the process of glycosylation. The interacting glycoproteins and membrane-bound enzymes are perceived as agents, with their own rules for movement, complex formation, biochemical reaction and dissociation. The resulting structures were saved into an XML-format, a mass spectrometry file and a GlycoWorkbench2-compatible file for visualization. Full article

Dry anaerobic digestion (DAD) is an attractive method for simultaneous organic waste disposal and bioenergy recovery. DAD has the problems of low methane yields, low reaction rates, and easy inhibition due to its limited mass transfer and heat transfer. In this work, two methods of mechanical stirring and percolate recirculation were compared regarding their capacities of improving the mass transfer and enhancing the performances of DAD in batch experiments with sorghum stalks as a substrate. The cumulative biogas yield and system stability were investigated when the stirring linear velocity was 0 cm/s, 22 cm/s, 44 cm/s, 66 cm/s, and 88 cm/s. When the stirring linear velocity was 88 cm/s, the cumulative biogas yield and methane content were highest. The computational fluid dynamics (CFD) simulation indicated that the shearing force near the stirring shaft was largest. When the linear velocity of the stirring paddle was 88 cm/s, the shearing force at a radial distance close to center was about −140 N/m². When the ratio of the material stacking height to the reactor diameter (H/D) was 3:2, the AD showed the best performance. A higher material stacking height promoted the contact between the microorganisms and the substrate and enhanced the biogas production. By combining percolate recirculation and mechanical stirring, the cumulative biogas yield increased by 28% compared with the static DAD process because of the promotion of mass transfer in the DAD. Full article

With global carbon emissions and environmental issues becoming increasingly prominent, there is an increasing focus on the development of clean energy, and biobutanol has gained widespread attention due to its superior performance. Butanol production by fermentation is affected by various factors, such as raw materials, cultivation environment, and butanol toxicity, which results in lower butanol production and restricts its industrial development. This article elaborates on the research progress of butanol fermentation, including butanol-producing microorganisms, butanol synthesis metabolic pathways, raw materials for ABE fermentation, and butanol fermentation technologies. It also looks forward to the prospects of biobutanol, aiming to provide a theoretical basis for the research direction of butanol fermentation. Full article

Torularhodin is a fungus-derived carotenoid, and the lack of downstream processing of torularhodin is still a challenge for its large-scale production. To support the industrial production of torularhodin, this work initially evaluated the efficiency of carotenoid release from Rhodotorula mucilaginosa using thermal acid treatment, saponification and ultrasound-assisted enzymatic lysis. Based on the polarity, torularhodin was then purified using methanol/acetone/hexane (2/2/1, v/v/v) solution eluting from a silica cartridge. Thermal acid treatment was considered the most appropriate method for total carotenoid release and torularhodin recovery. The highest carotenoid content was 121.3 ± 7.0 μg/g dry cell weight and 63.0 ± 6.1% of torularhodin (50.5 ± 3.0 μg/g dry cell weight in total) was recovered after purification. To fast quantify the content of torularhodin extracted from yeast, the absorption coefficient ($E_{1\mathrm{c}\mathrm{m}}^{1\%}$ = 3342) of torularhodin dissolved in chloroform was assayed. With the developed strategy for torularhodin recovery, purification and quantification, the potential of this yeast to produce torularhodin using xylose and glycerol was further evaluated. It was found that carbon sources may influence the proportion of carotenoids in this yeast, but torularhodin was still the dominant pigment. The results obtained in this study identified the feasibility of sustainable production of torularhodin from Rhodotorula mucilaginosa with high efficiency and purity. Full article

Biogas is a promising and robust renewable energy that holds potential as clean energy in the context of the current climatic emergency. Biogas has the immense advantage of coupling waste management and clean energy production. In other words, it is not only a renewable energy source, but also a central tool in recycling a vast range of waste products from the agroindustry. Despite its potential, the process is microbiologically complex and is usually carried out in both industrial and pilot laboratories, utilizing a variety of reactors and systems. In this work, we present a very simple, Do It Yourself (DIY) biogas fermenter that we have designed, operated, and characterized. We propose this technology as both an inexpensive proxy for biogas reactors in academic and private laboratories and as an effective dissemination tool to foster the knowledge and potential of biogas as a key technology to contribute to the development of a global bioeconomy. Full article

The implementation of a microbial fuel cell for wastewater treatment and bioenergy production requires a cost reduction, especially when it comes to the ion exchange membrane part and the catalysts needed for this purpose. Ionic liquids in their immobilized phase in proton exchange membranes and non-noble catalysts, as alternatives to conventional systems, have been intensively investigated in recent years. In the present study, a new microbial fuel cell technology, based on an ionic liquid membrane assembly for CoCu mixed oxide catalysts, is proposed to treat animal slurry. The new low-cost membrane–cathode system is prepared in one single step, thus simplifying the manufacturing process of a membrane–cathode system. The novel MFCs based on the new low-cost membrane–cathode system achieved up to 51% of the power reached when platinum was used as a catalyst. Furthermore, the removal of organic matter in suspension after 12 days was higher than that achieved with a conventional system based on the use of platinum catalysts. Moreover, struvite, a precipitate consisting of ammonium, magnesium, and phosphate, which could be used as a fertilizer, was recovered using this membrane–cathode system. Full article

Cocoa pod husks (CPH) and cocoa bean shells (CBS) are the main by-products of the cocoa industry and a source of bioactive compounds. These residues are not completely used and thrown in the fields without any treatment, causing environmental problems. Looking for a holistic valorization, the aim of this work was first to deeply characterize CPH and CBS in their chemical composition, amino acid, and fatty acid profiles, as well as their application as antioxidants. CBS had a high level of protein (17.98% DM) and lipids (16.24% DM) compared with CPH (4.79 and 0.35% DM respectively). Glutamic acid and aspartic acid were the predominant amino acids. The total phenolic compounds (TPC) detected in the ethanolic extracts of CPH and CBS were similar to pyrogallol as the main detected polyphenol (72.57 mg/L). CBS ethanolic extract showed a higher antioxidant activity than CPH. Both extracts increased the oxidation stability of soybean oil by 48% (CPH) and 32% (CBS). In addition, alkaline pretreatment of CPH was found suitable for the release of 15.52 ± 0.78 g glucose/L after subsequent saccharification with the commercial enzyme Cellic^®. CTec2. Alkaline hydrolyzed and saccharified CPH (Ahs-CPH) was assessed for the first time to obtain polyhydroxy alkanoate (PHAs) and bioethanol. Ahs-CPH allowed the growth of both Cupriavidus necator DSM 545 and Saccharomyces cerevisiae Fm17, well-known as PHA- and bioethanol-producing microbes, respectively. The obtained results suggest that such agricultural wastes have interesting characteristics with new potential industrial uses that could be a better alternative for the utilization of biomass generated as million tons of waste annually. Full article

Sheep bones are a rich resource in China, but their deep processing is limited by outdated technology. Sausages are popular among various consumer groups due to their unique flavor. The purpose of this study was to optimize the preparation process of fermented-enzymatic sheep bone powder and develop calcium-fortified functional sausages with an excellent flavor, aroma, and taste. In this experiment, the fermented-enzymatic sheep bone powder was prepared by optimizing the two-bacterial fermentation process of Lactobacillus Plantarum BNCC336421 and Pediococcus Pentosaceus BNCC193259. The nutritional indexes and micro-structure were analyzed. Additionally, different ratios of fermented sheep bone powder were added into the sausages to investigate their effects on the nutritional indexes, physicochemical properties, and organoleptic quality of the sausages. The results showed that the optimal process conditions for the fermented sheep bone sludge were as follows: a strain inoculation of 3%; a compounding ratio of 1:1; a bone sludge concentration of 1:20; and fermentation time of 24 h. Under these conditions, the Ca²⁺ content and protein hydrolysis degree of the sheep bone were 2441.31 mg/100 mL and 23.78%, respectively. The fermented sheep bone powder analyzed using SEM, and the particle size analysis showed it was loose and porous with a small particle size. The addition of fermented sheep bone powder to the sausage increased its amino acid and calcium ion contents, improved the texture indexes such as cohesion, and enhanced both the L* value and sensory scores. The best result was observed in the 1% group (p < 0.05). It serves as a data source for developing fermented sheep bone powder and its application in sausage, offering a fresh idea and approach to achieving the high-value utilization of sheep bone. Full article

Different carbon sources, such as prebiotics, have promoted probiotics’ survival during refrigerated fermented milk storage. These compounds stimulate both the metabolic response and the resistance of probiotics to adverse conditions, such as low temperatures. That is why the objective of this study was to evaluate the kinetic parameters of growth, the proteolytic profile, and the survival of Lactiplantibacillus pentosus ABHEAU-05 in fermented milk added with aguamiel as a prebiotic source during refrigerated storage. Inulin was used for control experiments. A 12% w/v powdered skimmed milk solution was inoculated with L. pentosus ABHEAU-05 (10⁶ CFU/mL). It was fermented at 37 °C until a pH of 4.5, and the kinetic parameters were calculated. Analysis of survival and proteolytic profile during refrigeration storage (4 °C for 21 days) was carried out. The survival of the microorganism was determined by viable count on MRS agar, the production of free amino groups by the TNBS method, and the accumulation of low molecular weight peptides by polyacrylamide gel electrophoresis (SDS-PAGE). The pH of 4.5 was reached 26 h before the control. The maximum concentration of viable cells was 10⁸ CFU/mL at the fermentation’s end and maintained throughout the refrigerated storage. With the analysis of the proteolytic profile, high metabolic activity was demonstrated during fermentation and refrigerated storage in milk with aguamiel. The accumulation of low molecular weight peptides and the generation of free amino groups were higher than the control results. It was verified that aguamiel is a carbon source with the potential for developing and maintaining the probiotic L. pentosus ABHEAU-05 in fermented milk. Full article

In the current investigation, the woody stem of Moringa oleifera was processed by chipping and milling and was subsequently exposed to a combination of pretreatments involving a 3% v/v solution of nitric acid and autohydrolysis. The simultaneous saccharification and fermentation (SSF) of the pretreated hydrolysate of M. oleifera was conducted using Zymomonas mobilis and Kluyveromyces marxianus in occurrence of commercial cellulase enzyme, Tween 80, and sodium azide. The fermentation process parameters for Z. mobilis were optimized individually, including a substrate concentration of 5% (w/v), concentration of inoculum 5% (v/v), pH 5.4, and temperature 34 °C. Similarly, for K. marxianus, the process parameters were optimized individually, with a substrate concentration of 5% (w/v), an inoculum concentration of 3% (v/v), a pH of 5.1, and a temperature of 41 °C. The highest cellulosic ethanol concentration was achieved by the micro-organism K. marxianus after a fermentation period of 96 h. Full article

The biorefinery industry is witnessing a transition from fossil and chemical-based processes to more sustainable practices, with a growing emphasis on using renewable resources. Sophorolipids, a promising group of biosurfactants, present a viable substitute for conventionally produced surfactants. This study focuses on microbial fermentation using yeast and lipid substrate for sophorolipid production. The life cycle assessment (LCA) methodology was employed to identify environmental hotspots of the process and to assess the environmental benefits resulting from the replacement of raw rapeseed cooking oil (base scenario) with waste cooking oil, reduction of process electricity consumption, and increased sophorolipid yield. By compiling scenarios with the lowest environmental impact, a best-case scenario was created. The results revealed that the environmental impact of sophorolipid production could be reduced by 50% in the best-case scenario compared to the base scenario. This research provides valuable insights into the environmental optimization of the fermentation process and through the application of LCA highlights the potential for the reduction of negative environmental impact of sophorolipid production, contributing to the ongoing transition from petroleum oil and petrochemical refineries to sustainable biorefineries. Full article

The plethora of bio-functional compounds present in fermented alcoholic beverages like wine, as well as the valorisation of bioactives from wineries’/breweries’ by-products like grape pomace and grape seed, has gained significant interest in the functional foods sector. This functional beverage, wine, has always accompanied humanity, for religion or for health, especially in the Mediterranean, while the benefits of its moderate consumption were documented even by the Greek physician Hippocrates of Kos (460–370 BC). After a big gap, an outbreak of research on wine benefits has surfaced only since the 1990s, when the term “French paradox” was introduced to the US public during a CBS show, while recent evidence has outlined that the beneficial effects of wine consumption are derived by the synergisms of its bio-functional compounds and their digestion-derived metabolites. Within this article, the proposed health benefits of moderate wine consumption, as a functional component of a balanced diet (i.e., the Mediterranean diet) against inflammation-related chronic disorders, is thoroughly reviewed. The various bio-functional compounds of both wine and wineries’ by-products, such as their bioactive phenolics, unsaturated fatty acids, polar lipids and dietary fibres, and their functional antioxidant, anti-inflammatory and antithrombotic health-promoting properties, are also thoroughly evaluated. The mechanisms of action and synergism, by which the health benefits are elicited, are also explored. Functional properties of non-alcoholic wine products are also introduced. Emphasis is also given to applications of wineries’ by-products bioactives, as ingredients of bio-functional foods, supplements and nutraceuticals. Limitations and future perspectives for this popular functional alcoholic beverage (wine) and its rich in bioactives by-products are also addressed. Full article

Spore-forming bacteria in silage may reduce dry matter intake or affect dairy product quality when transferred to milk. The present study investigated the effects of three facultative anaerobes (Bacillus cereus, Bacillus subtilis, and Bacillus licheniformis) and two strict anaerobes (Clostridium tyrobutyricum and Clostridium beijerinckii) commonly found in low-quality silage, milk, and cheese. Maize silage was intentionally contaminated with these spore formers in separate mini silos at 1 × 10⁵ CFU spore former per g and treated with commercial silage inoculant Lentilactobacillus buchneri NCIMB 40788 at 4 × 10⁵ CFU per g or left untreated. The microbial and chemical profiles of maize silage, which were determined using Nuclear Magnetic Resonance (NMR), were measured after fermentation for 100 days, and they were also measured for silage exposed to air for 72 h after opening at 100 days. The effect of the inoculant strain L. buchneri NCIMB 40788 on these contaminated silages was investigated to determine if the inoculant could prevent/limit the negative impacts caused by the spore former contaminants. Overall, inoculation improved silage quality and aerobic stability. Acetic acid content was higher in the INOC samples than in the NIS (p < 0.001), while lactic acid content was lower in INOC than in NIS (p < 0.001). Both lactic and acetic acid levels were higher in the silage samples contaminated with B. cereus. Contamination with the spore formers increased the aerobic and anaerobic spore counts of the samples contaminated with B. subtilis and B. licheniformis compared to the control silage after opening. After 3 days of aerobic exposure, the samples contaminated with B. cereus, B. subtilis, and B. licheniformis showed higher aerobic spore counts than the control. The dominant bacterial population was significantly modified by inoculation. Neither inoculation nor contamination types impacted fungal populations upon opening, but a dominance of Wickerhamomyces was observed after aerobic exposure in the B. cereus silages. The γ-aminobutyrate (GABA) content after aerobic exposure was higher than the uncontaminated control for the silage contaminated with B. licheniformis. The samples contaminated with Clostridium species remained largely unchanged compared to the control samples. Physicochemical and bacterial profiles were mainly affected by inoculation, and a limited impact of spore contaminant was noted. Our results show that when L. buchneri inoculation was carried out, higher aerobic and anaerobic spore counts following contamination with bacterial spore formers were mitigated after reaching aerobic stability. Full article

Penicillium roqueforti is a fungal starter culture used for the production of blue-veined cheeses, such as Roquefort, Gorgonzola, Stilton, Cabrales, and Danablue. During ripening, this species grows in the veins of the cheese, forming the emblematic blue-green color and establishing the characteristic flavor owin to its biochemical activities. P. roqueforti synthesizes a diverse array of secondary metabolites, including the well-known compounds roquefortine C, clavine alkaloids, such as isofumigaclavine A and B, mycophenolic acid, andrastin A, and PR-toxin. This review provides an in-depth exploration of P. roqueforti’s secondary metabolites, focusing on their biosynthetic pathways, the gene clusters responsible for their production, and their bioactivities. The presence of these compounds in blue cheeses is also reviewed. Furthermore, the silent clusters and the potential of P. roqueforti for producing secondary metabolites were discussed. The review highlights recently identified metabolites, including sesterterpenoids; tetrapeptides, D-Phe-L-Val-D-Val-L-Tyr, and D-Phe-L-Val-D-Val-L-Phe; cis-bis(methylthio)silvatin; and the 1,8-dihydroxynaphthalene (DHN)-melanin precursor, scytalone. Additionally, a gene cluster for DHN–melanin biosynthesis is presented. Finally, a revised cluster for roquefortine C biosynthesis comprising three rather than four genes is proposed. Full article

Sargassum fusiforme polysaccharides (SFPs) have multiple activities. The fermentation of S. fusiforme by Lactobacillus can alter its polysaccharide properties and biological activities. In this study, three different Lactobacillus species (Lactobacillus plantarum (LP), Lactobacillus acidophilus (LA), and Lactobacillus rhamnosus (LR)) were selected to ferment S. fusiforme. The polysaccharides SFP (unfermented) and FSFP (fermented by LP, LA, or LR denoted as LP-SFP, LA-SFP, and LR-SFP, respectively) were extracted, and their physicochemical properties and biological activities were investigated. According to the results, fermentation caused significant changes in the physicochemical properties and biological activities of SFP. Specifically, FSFP showed a significant increase in uronic acid and fucose content and a significant decrease in molecular weight; LA-SFP and LR-SFP had stronger DPPH scavenging abilities; LR-SFP had the strongest inhibition of ROS production and cell mortality; LP-SFP and LR-SFP significantly increased SOD activity in zebrafish; LA-SFP had a significant effect on the proliferation of Lactobacillus plantarum; LP-SFP had a significant effect on the proliferation of Lactobacillus rhamnosus; and LA-SFP had a stronger food-excretion-promoting activity. In conclusion, the fermentation of Lactobacillus for the preparation of SFPs can change the physicochemical properties of polysaccharides and has broad potential for improving their biological activity. Full article

The biomethane accumulation of several combinations of whey and sugarcane molasses, inoculated with sludge from a treatment facility of one of the dairy enterprises of the Imbabura province in Ecuador, was assessed in the current experiment at a constant COD₀/VS_in ratio of 0.5. The whey/molasses (W:M) ratios for each treatment were (in % (m/m)) 0:100, 25:75, 50:50, 75:25, and 100:0, with a constant temperature of 37 °C and an initial pH adjustment of 7.5. Half a litre of total mixes was used for each treatment in duplicate. Six kinetic models were evaluated to account biomethane accumulation in anaerobic co-digestion processes in batch of whey and sugarcane molasses. Five of these have been tested by other researchers, and one was developed by modifying a first-order model to consider changes in the biomethane accumulation profile. This proposed model, along with the modified two-phase Gompertz model, resulted in the ones that were best able to adjust the experimental data, obtaining in all cases an R² ≥ 0.949, indicating the accuracy of both models. In addition, the proposed here model has five parameters, one less than the modified two-phase Gompertz model, making it more straightforward and robust. Full article

The International Water Association’s (IWA) established Anaerobic Digestion Model No. 1 (ADM1) was created to serve as a backup for experimental findings regarding the actual anaerobic digestion process. The previous model idea was adjusted and used to simulate an anaerobic digestion process in this study. Testing procedures, such as benchmark tests and balance checks, were performed in order to verify the accuracy of the implementation. These measures worked in tandem to ensure that the model was implemented flawlessly and without inconsistencies. The primary objective of this article is to construct a method that is based on the ADM1 for evaluating co-digestion and predicting the performance of the digestion process or methane yield based on the analyzed substrates’ physicochemical properties. Additional equations and simulations have been added to the standard model to create tools for evaluating the feasibility of anaerobic co-digestion. The study’s two most intriguing aspects are the optimal mixture and parameter dependence. The adjusted ADM1 is accurate in predicting the measured values of effluent COD, pH, methane, and produced biogas flows with a reasonable degree of accuracy, according to the validation results. This research shows how to use ADM1 in a wastewater treatment plant and other settings where anaerobic digestion is of interest. Full article

A healthy lifestyle and environmental protection play a big role in today’s modern society. The production of organic wine, as with other organic commodities, is therefore becoming increasingly popular with consumers. The selling price of organic wine is higher than that of wine that is not declared organic or BIO, so the question arises from consumers as to whether these wines contain more bioactive compounds and substances beneficial to the body. From a general point of view, it is known that grapevines contain a wide range of natural phenols and polyphenols. These substances affect the sensory properties of wines, especially color and taste. The most phenolic substances are found in red wines, slightly less in orange wines, and the lowest amounts are found in white wines. However, the representation of individual substances and their ratios differs based on the varieties and age of the wines. Therefore, this study aimed to compare the profile (chemical, physical, and sensory) of organic wines compared to wines created from nonorganic grapes, which are grown in a selected wine region—Kutná Hora. The analyzed wines were created from the same grape wine cultivar in the Kutná Hora area. The following analyses were performed on the wine samples: the phenolic and antioxidant profiles, the content of sulfites (free and total), alcohol, sugars, vitamins, density determination, and also sensory evaluation. The present study showed exact differences between samples of wines produced from the same cultivar and the same region, but declared as organic wines and wines from conventional production. Although a higher number of bioactive substances is expected in wines from organic production, in most cases it did not show a statistically significant difference in the sense of a higher amount in BIO wines; on the contrary, in many cases, the content of these substances was higher in wines from integrated production. Full article