Search Results (6,672)

Medical cannabis cultivation requires substantial energy for heating, lighting, and climate control. This study evaluates the economic feasibility of an innovative biomass-fired micro-CHP system in a greenhouse facility for medicinal cannabis cultivation. The system comprises an 80 kW_th boiler retrofitted for biomass and a 7 kW_el ORC engine and is assessed against a diesel-boiler Business-As-Usual (BAU) benchmark. Thermal load simulations for two growing periods (1 March–30 June and 1 September–30 December) estimate an annual heating demand of 91,065.20 kWh_th. The micro-CHP system delivers 8195.87 kWh_el per year, exceeding the greenhouse’s 7839.90 kWh_el consumption. Over a 30-year lifespan at a 7% discount rate, Life Cycle Costing yields EUR 196,421.33 for micro-CHP versus EUR 229,468.46 for BAU, a 14.4% reduction. Under all-equity financing, the project achieves an NPV of EUR 59,591.88, IRR of 27.32%, and a DPBP of 12.1 years; with 70% debt financing, NPV rises to EUR 61,211.39 and DPBP shortens to 10.5 years. Levelized Cost of Energy (LCOE) and Heat (LCOH) are EUR 0.122 per kWh_el and EUR 0.062 per kWh_th, respectively. While the LCOE is below the Greek and EU non-household averages (EUR 0.1578 and EUR 0.1515 per kWh_el), the LCOH exceeds the corresponding heat price benchmarks (EUR 0.0401 and EUR 0.0535 per kWh_th). These results indicate that, in the modeled context, biomass-ORC cogeneration can be a financially attractive and lower-carbon option for medicinal cannabis greenhouse operations. Full article

The escalating threat of cyanobacterial blooms necessitates a deeper understanding of the environmental factors regulating their toxicity. While light intensity effects are well-documented, it remains unclear whether photoperiod regulates microcystin (MC) production. This study investigates the effects of five light–dark (LD) cycles on the growth and MC-LR production of two Microcystis strains in batch culture under a light intensity of 25 μmol m⁻² s⁻¹. Longer photoperiods enhanced early growth, although long-term biomass accumulation proved strain-dependent. Regarding toxin production, cellular MC-LR (total toxin per cell) during the initial 9-day phase was analyzed using a mixed-effects model. The analysis revealed significant main effects of photoperiod and cell density, supporting both direct and growth-mediated indirect effects of photoperiod. Moreover, a significant strain × photoperiod × day interaction (p < 0.001) was observed, indicating additional strain-specific and time-dependent regulation. Conversely, a general linear model of the strictly intracellular MC-LR at the 27-day endpoint showed significant independent effects of photoperiod and cell density, with no interaction. The photoperiod effect strengthened after controlling for cell density. These findings reveal a phase-dependent regulation of toxicity, suggesting that risk assessment based solely on biomass is inadequate. Sustainable bloom management should therefore incorporate photoperiod dynamics and adopt phase-specific strategies. Full article

The large-scale cultivation of medicinal plants generates substantial agricultural by-products that are often discarded. A notable example is the floral biomass of Bupleurum chinense DC. (B. chinense), which is routinely removed during cultivation to promote root yield. To explore the potential valorization of these discarded tissues, we performed an integrated transcriptomic and metabolomic analysis of flavonoid biosynthesis across three developmental stages: F1 (Initial Flowering Stage), F2 (Full Bloom Stage), and F3 (Late Flowering Stage). Our results revealed distinct stage-specific regulatory dynamics. Flavonoid biosynthesis was initiated at F1 through the activation of upstream structural genes, reached its peak at F2 with strong up-regulation of branch-specific genes and the accumulation of diverse flavonols and anthocyanins, and declined at F3, despite the sustained presence of several antioxidant metabolites. These findings indicate that F2 represents the optimal stage for harvesting B. chinense flowers to obtain a broad spectrum of bioactive flavonoids, while late-stage flowers may serve as a complementary source of stable antioxidant compounds. Collectively, this study highlights the potential for transforming discarded floral biomass into valuable phytochemical resources and provides a framework for exploring underutilized tissues in other medicinal plants. Full article

Fructophilic lactic acid bacteria (FLAB), Apilactobacillus kunkeei strains AG8 and AG9 were selected in the current study for in-depth analysis. Cultivation on fructose yeast peptone (FYP) medium with varying fructose concentrations (1%, 10%, and 30%) revealed that higher fructose levels promoted acetate production over lactate, confirming a heterofermentative metabolic profile. Ethanol production was negligible, consistent with the absence of alcohol dehydrogenase (ADH) activity. Enzyme assays showed fructokinase activity doubled at 30% fructose, while acetate kinase activity increased and L-lactate dehydrogenase activity decreased. This shift in enzyme ratios from 1:1 at 1% fructose to 10:1 or 15:1 at higher concentrations explains the metabolic preference for acetate. Apb. kunkeei is an obligate FLAB, growing poorly on glucose unless supplemented with external electron acceptors like pyruvate or oxygen. It lacks ADH, but retains acetaldehyde dehydrogenase (ALDH), enabling acetate production and additional ATP generation, enhancing biomass yield. The absence of the adhE gene contributes to NAD+/NADH imbalance and favors acetate production. Gene expression studies targeting fructose transport enzymes showed elevated expression of ABC transporters and carbohydrate metabolism genes in response to fructose. ADH expression remained low across sugar concentrations. Fructokinase gene expression was shown to be strain specific. Neither strain expressed the ABC transporter ATP-binding protein gene on glucose, nor the bacteriocin ABC transporter gene, correlating with the absence of antibacterial activity. These findings underscore the metabolic specialization of Apb. kunkeei, its reliance on fructose, and the role of ABC transporters in optimizing fermentation. The strain-specific gene expression and metabolic flexibility highlight its potential as a probiotic and feed additive in apiculture and biotechnology. Full article

Biosynthesis of ribose-5-phosphate (R5P) underlies all biosynthetic processes associated with biomass growth. Actively dividing cells continuously require building blocks for genome replication, synthesis of ribosomes and other derivatives containing R5P as a carbohydrate backbone. The main source of R5P in the cell is the pentose phosphate pathway (PPP), which is an anabolic sensor designed to coordinate the level of pentose phosphates and reduced NADPH required for anabolic processes. This review is devoted to a comparative analysis of R5P biosynthesis pathways among different domains of microorganisms, the features of PPP regulation in bacterial cells depending on physiological conditions, as well as genetic modifications of PPP and their effect on cell viability. We emphasize that ribose metabolism is a factor in the consolidation of cellular homeostasis under conditions of intensive biomass growth and the discrepancy between the processes of ribose synthesis and consumption is marked by spontaneous cell death. Full article

This study aimed to assess the potential of machine learning models applied to high spatial resolution images from UAVs for estimating the aboveground biomass (AGB) of forage grass cultivated in the Brazilian semiarid region. The fresh and dry AGB were determined in Cenchrus ciliare plots with an area of 0.04 m². Spectral data were obtained using a multispectral sensor (Red, Green, and NIR) mounted on a UAV, from which 45 vegetation indices were derived, in addition to a structural variable representing plant height (H95). Among these, H95, GDVI, GSAVI2, GSAVI, GOSAVI, GRDVI, and CTVI exhibited the strongest correlations with biomass. Following multicollinearity analysis, eight variables (R, G, NIR, H95, CVI, MCARI, RGR, and Norm G) were selected to train Random Forest (RF), Support Vector Machine (SVM), and XGBoost models. RF and XGBoost yielded the highest predictive performance, both achieving an R² of 0.80 for AGB—Fresh. Their superiority was maintained for AGB—Dry estimation, with R² values of 0.69 for XGBoost and 0.67 for RF. Although SVM produced higher estimation errors, it showed a satisfactory ability to capture variability, including extreme values. In modeling, the incorporation of plant height, combined with spectral data obtained from high spatial resolution imagery, makes AGB estimation models more reliable. The findings highlight the feasibility of integrating UAV-based remote sensing and machine learning algorithms for non-destructive biomass estimation in forage systems, with promising applications in pasture monitoring and agricultural land management in semi-arid environments. Full article

This study assesses the ecological conditions of the Colentina urban river system by investigating phytoplankton community traits, with a focus on resource use efficiency (RUE) as a functional indicator. Using phytoplankton biomass, taxonomic composition, and RUE, we assessed the ecological effects of anthropogenic pressures. Our results showed that total phosphorus values indicated chronic eutrophication conditions but supported increased phytoplankton biomass, especially in spring and summer. RUE varied independently of biomass, with maximum values recorded in autumn, suggesting a functional recovery phase, characterized by higher RUE under nutrient decline. The analysis at the phytoplankton group level highlighted distinct ecological strategies: cyanobacteria presented a high RUE in autumn, diatoms increased their efficiency during nutrient limitation periods, and green algae showed a functional flexibility throughout the study period. In contrast, spatial analyses indicated a decoupling between biomass and RUE, reflecting the influence of local environmental conditions on ecosystem functioning. RUE was significantly influenced by total phosphorus, nitrogen forms, temperature and light availability. Our results strengthen the combined approach of structural (biomass) and functional (RUE) indicators for the assessment of communities and anthropogenic impacts in urban and peri-urban aquatic ecosystems. Full article

Chaetognaths play an essential role in zooplankton communities and significantly contribute to their overall biomass. Changes in the hydrographic properties of the water column, driven by hydrodynamic processes, affect their species richness and abundance. This study investigates the species richness and abundance of chaetognaths, as well as their relationship with circulation patterns at the boundary of the Pacific Ocean and the Gulf of California, Mexico. The analysis is based on high-resolution hydrographic data and zooplankton samples collected during the early summer of 2019. The results revealed a cyclonic circulation pattern that impacted the chaetognath community at depths greater than 200 m. This pattern resulted in higher chaetognath densities along the peninsular coast compared to the mainland coast. A total of 15 species from three different families were identified. Among these, Flaccisagitta enflata had the highest density, recorded at 16,143 ind 100 m⁻³, while Aidanosagitta neglecta exhibited a significantly lower density of only 48 ind 100 m⁻³. Multivariate statistical analyses indicated that hydrographic variables were key factors influencing the distribution of the chaetognath community during the sampling period. Given the significant research gap regarding this group in the region, our findings contribute to a deeper understanding of chaetognath communities and their relationship with circulation patterns in the Southern Gulf of California, recognized as an oasis of marine life. Full article

Hydropower is the primary source of electricity in several countries in Latin America. Hydropower provides approximately 80% of Ecuador’s electricity; however, it remains highly vulnerable to climate change, resulting in uncertainties in power generation due to altered precipitation patterns, runoff, and systematic failures. Consequently, Ecuadorians are becoming increasingly reliant on diesel generators during crises, resulting in public health, safety, and economic impacts, as well as social and political disruptions. This study evaluated noise pollution in the central urban area of the city of Loja for the first time during the 2024–2025 electricity crisis in Ecuador. A Type 1 integrating sound-level meter was used to monitor noise pollution (LAeq, 10min) at 20 locations during periods of generator operation and non-operation. At each location, the number of generators, the density of commercial activities along the streets, as well as traffic and other urban characteristics, were recorded. Results revealed that the presence of generators, street width, and the number of generators significantly increased the LAeq, 10min, often exceeding the limits set by the World Health Organization and Ecuador’s environmental regulations. Frequency spectrum analysis revealed that medium frequencies increased with A-weighting, while low frequencies rose with C-weighting, suggesting potential health risks to the local population. The thematic noise map during generator inactivity showed lower noise levels, averaging around 71.5 dBA. Conversely, when the generators were operational, noise levels exceeded 79.6 dBA, indicating a significant increase in environmental noise exposure associated with their use. This highlights an urgent need to implement and expand renewable energy sources, as existing options like wind power, photovoltaic energy, and biomass are insufficient to meet community demands. Full article

The increasing biogeochemical imbalance of nitrogen (N) heightens the importance of studying rhizosphere bacteria, which aid crop nutrient uptake, and their responses to N deficiency. The aim of the study was to assess variety-specific responses of the tomatoes and their associated rhizobacteriome to low N availability. Three determinant varieties of Solanum lycopersicum L. were cultivated in pot-scale experiment during 10 weeks on low-fertility substrate (sod-podzolic soil:peat:clay:sand, 1:1:1:2, v/v), half of which were supplemented with ammonium nitrate (60 mg N kg⁻¹ in total). A comprehensive methodology was employed, including 16S rRNA metagenomic Nanopore sequencing, quantitative assessment of N-cycling bacteria, and analysis of plant growth, photosynthetic pigments, total N in biomass, and fine root architecture. Results demonstrated that N deficiency significantly reduced plant biomass and photosynthetic pigments. The rhizosphere contained a diverse community of N-transforming bacteria (38 identified genera), whose composition and relative abundance were strongly influenced by both tomato variety and N fertilization. Nitrogen application increased the abundance of N-fixers and altered alpha-diversity in a variety-dependent manner. Significant correlations were found between the abundance of key bacterial genera (e.g., Stenotrophomonas, Rhizobium) and N parameters in plants and substrates. The study concludes that the response of the tomato rhizobacteriome to N availability is variety-specific, which is important for the development of microbiome management strategies for enhancing N use efficiency. Full article

The northwest of Mexico has important zones for biodiversity conservation, denominated Priority Marine Regions (PMRs), and to study key oceanographic features related to ecological structure, it is necessary to understand environmental variability and observe climatic trends. Sea Surface Temperature (SST) is tightly associated with photosynthesis and serves as a control and driver for biological processes linked to the phytoplankton. Global climatic systems, like El Niño Southern Oscillation (ENSO), are responsible for the interannual and interdecadal variation in SST, since global circulation is modified by them. An important metric to assess phytoplanktonic biomass/photosynthesis is Chlorophyll a (Chl a), constituting the primary basis of the marine trophic web. The present study aims to examine the interannual oceanographic variability across 24 PMRs by employing monthly SST (°C) and Chl a (mg/m³) data derived from remote sensing instruments with spatial resolution of 4 km and 1 km from September 1997 to October 2018. We grouped the Priority Marine Regions into 18 main areas, based on a cluster analysis of Sea Surface Temperature. Significant differences were observed, showing higher SST levels during El Niño phase and higher Chl a concentration during La Niña phase, primarily in winter and spring, which will impact marine ecosystems. Full article

This study investigated sawdust-derived activated carbon (SAC) as a sustainable reinforcing filler for vulcanized rubber bushings (VRBs). Two types SAC200 (75 µm, carbonized at 200 °C) and SAC400 (38 µm, carbonized at 400 °C) were chemically activated and incorporated into natural rubber (NR) at 25–55 phr loadings, while SAC free VRBs served as controls. Fourier transform infrared (FTIR) analysis revealed that SAC400 exhibited stronger hydroxyl and carbonyl functional groups, indicating higher surface reactivity compared with SAC200. The incorporation of SAC increased cross-linking density, thereby enhancing both curing behavior and mechanical performance. VRBs reinforced with SAC400 demonstrated higher maximum torque (up to 38.07 kg·cm), shorter scorch time (5 min 58 s), and reduced cure time (11 min 05 s) relative to SAC200 and the control. Mechanical properties improved markedly, with hardness and tensile strength rising from 45 Shore A and 5.52 MPa in the control to 70 Shore A and 13.40 MPa in SAC400. Although elongation at break decreased slightly, it remained within the acceptable range for dynamic applications. Swelling resistance also increased, reaching 101.76% at 25 °C and 106.61% at 100 °C. Overall, SAC400 consistently outperformed SAC200 and the control, highlighting its potential as a renewable, biomass-derived filler for high-performance rubber bushings and promising a sustainable alternative to conventional fillers in industrial applications. Full article

Microbial metabolism is intricately governed by thermodynamic constraints that dictate energetic efficiency, growth dynamics, and metabolic pathway selection. Previous research has primarily examined these principles under carbon-limited conditions, demonstrating how microbes optimize their proteomic resources to balance metabolic efficiency and growth rates. This study extends this thermodynamic framework to explore microbial metabolism under various non-carbon nutrient limitations (e.g., nitrogen, phosphorus, sulfur). By integrating literature data from a range of species, it is shown that growth under anabolic nutrient limitations consistently yields more negative Gibbs free energy ($\Delta G$) values for the net catabolic reaction (NCR) per unit of biomass than carbon-limited scenarios. The findings suggest three potentially complementary hypotheses: (1) proteome allocation hypothesis: microbes favor faster enzymes to reduce the proteome fraction used for catabolism, thus freeing proteome resources for additional nutrient transporters; (2) coupled transport contribution hypothesis: the more negative $\Delta G$ of the NCR may in part stem from the increased reliance on ATP-coupled or energetically driven transport mechanisms for nutrient uptake under limitation; (3) bioenergetic efficiency hypothesis: microbes prefer pathways with a more negative $\Delta G$ to enhance the cellular energy status, such as membrane potentials or the ATP/ADP ratio, to support nutrient uptake under anabolic limitations. This integrative thermodynamic analysis broadens the understanding of microbial adaptation strategies and offers valuable insights for biotechnological applications in metabolic engineering and microbial process optimization. Full article

Entomopathogenic fungi of the genus Beauveria are recognized for their dual role as insect pathogens and plant endophytes, however the majority of research efforts to date have centered on B. bassiana. To address this bias, we evaluated the endophytic traits of five Beauveria species (B. bassiana, B. brongniartii, B. aranearum, B. amorpha, and B. velata) in tomato (Solanum lycopersicum). Tomato seedlings were inoculated by root drenching with 1 × 10⁸ conidia/mL suspensions, and colonization, plant growth, and resistance to Botrytis cinerea were assessed. All five species colonized tomato tissues, with colonization rates from 33.3% (B. velata) to 56.7% (B. brongniartii). Growth promotion was species dependent: B. bassiana, B. brongniartii, and B. aranearum significantly increased plant height, while B. brongniartii enhanced aboveground biomass. In pathogen assays, all Beauveria-treated plants showed reduced gray mold incidence and severity, with B. brongniartii conferring complete protection. Transcriptome analysis identified 160 differentially expressed genes commonly regulated, including 17 upregulated genes enriched in defense responses, hormone signaling, and photosynthesis. These findings demonstrate that non-B. bassiana species can establish endophytic associations, promote growth, and induce resistance in tomato, expanding the potential of Beauveria spp. as biocontrol agents in sustainable agriculture. Full article

Excessive nitrogen addition in farmland on the Loess Plateau reduces soil quality and endangers the atmospheric environment. We designed an experiment to investigate the effects of different nitrogen application rates on the soil physicochemical properties and microbial diversity of spring wheat fields on the Loess Plateau, aiming to identify the optimal nitrogen application rate and avoid the detrimental effects of excessive nitrogen addition. A field experiment was conducted from 2022 to 2023 with four nitrogen (N) application rates (0, 55, 110, and 220 kg·N·ha⁻¹·y⁻¹). This study aimed to assess the changes in soil properties, nutrient contents, enzyme activities, and bacterial community structure. The results showed that increasing N application generally enhanced soil bulk density, nitrate nitrogen (NO₃⁻-N), ammonium nitrogen (NH₄⁺-N), and microbial biomass nitrogen (MBN) (p < 0.05). In contrast, soil water content initially increased and then decreased. Soil organic carbon and total nitrogen rose markedly with higher N inputs, particularly in the 0–20 cm layer, whereas total phosphorus was less affected. Nitrogen addition stimulated soil enzyme activities (protease, urease, nitrate reductase, and nitrite reductase), though excessive input (220 kg·N·ha⁻¹·y⁻¹) produced inhibitory effects. Actinobacteria (relative abundance: 29–35%) and Proteobacteria (relative abundance: 14–22%) were the dominant phyla in all treatments. Alpha diversity peaked at low nitrogen input (55 kg·N·ha⁻¹·y⁻¹), while high N level reduced evenness and species richness (p < 0.05). Principle Coordinate Analysis (PCoA) revealed that both N application and soil depth shaped microbial community assembly, with deeper layers (20–40 cm) being more sensitive to N input. Correlation analysis indicated that soil moisture, bulk density, and C:N:P stoichiometry were key drivers of bacterial community variation. Overall, moderate nitrogen input (110 kg·N·ha⁻¹·y⁻¹) improved soil fertility and supported microbial functionality, whereas excessive application degraded soil structure and reduced biodiversity. These findings highlight the need for balanced N management strategies in rain-fed agriculture of the Loess Plateau to sustain both productivity and ecological stability. Full article