Biodegradation最新文献

Chlorantraniliprole, as a widely used plant protection product, raises concerns about the environment due to its moderately persistent residues. The present investigation involved the in vitro degradation of chlorantraniliprole by bacteria isolated from farmgate fruits and vegetables from pesticide-intensive fields. A total of 10 different bacterial isolates were obtained and characterised through several morphological characters as well as biochemical tests and 16S rRNA sequencing. Out of the total 10 isolates, 9 were from the genus Klebsiella and 1 from Staphylococcus. The degradation of chlorantraniliprole was assessed using the ten isolates of bacteria in diluted nutrient broth at two different inoculum concentrations (1 and 5%) over three different time intervals (0, 5, and 10 days after inoculation). K. pneumoniae (PPCO1) was found to be the most potent bacterium for degradation of chlorantraniliprole, with a degradation capability of 85.36%, over other isolates and degradation was lowest in S. epidermidis (PSGCO1) (77.32%) on the 10th day after inoculation. These results highlight the potential of Klebsiella spp. and S. epidermidis as promising candidates for the removal of chlorantraniliprole residues in broth under controlled conditions; however, field validation is essential to confirm their efficacy in mitigating pesticide residues under natural environmental settings.

Salinity is a major abiotic stress limiting maize (Zea mays L.) productivity, particularly in arid and semi-arid regions. This study evaluated the efficacy of gibberellic acid (GA₃) and biochar in mitigating salinity-induced growth inhibition in maize. The objective was to assess the synergistic effects of GA₃ and biochar on germination, growth parameters, and photosynthetic capacity under saline conditions, and to identify practical strategies for improving crop performance in salt-affected soils. A pot experiment was conducted at the Islamia University of Bahawalpur, Pakistan, using a Completely Randomized Design (CRD) with four replications per treatment, resulting in 32 pots. The study included eight treatment combinations: control, GA₃, biochar, and GA₃ + biochar under two salinity levels (2.41 and 6 dS·m⁻¹). Key parameters analyzed included germination rate, shoot and root length, shoot and root biomass, protein content, and chlorophyll content. Under high salinity (6 dS·m⁻¹), the combined application of GA₃ and biochar improved germination to 73.5% ± 0.5 compared to 66.5% ± 0.5 in the control. Shoot and root lengths increased to 16.28 ± 0.15 cm and 5.90 ± 0.12 cm, respectively, compared to 10.73 ± 0.45 cm and 5.16 ± 0.05 cm in the control. Chlorophyll content also increased, indicating improved photosynthetic performance. The findings demonstrate that GA₃ and biochar together can alleviate the adverse effects of salinity stress by promoting early growth and physiological performance in maize. Incorporating these amendments into agronomic practices may provide a sustainable strategy to enhance maize productivity in saline soils. Future studies should evaluate their long-term effects on soil health, nutrient dynamics, and crop yield under field conditions.

Organic micropollutants (OMP) pose a significant environmental challenge, and microbial degradation research typically involves monitoring parent compound depletion and metabolite production. Previous studies on the antibiotic sulfamethoxazole (SMX) have shown its incomplete biotransformation by either mixed microbial communities or acclimated pure bacterial across various concentrations. However, the mechanisms behind this incomplete degradation and its relationship with the enzymatic capacities and expressions at environmentally relevant concentrations remain unclear. Therefore, this study investigated the biotransformation of SMX and the variations in the proteome at low µg L⁻¹ concentrations using acclimated Microbacterium sp. BR1 as the bacterial degrader. Results show an incomplete depletion of the SMX and accumulation of the metabolite 3-amino-5-methylisoxazole (3A5MI). All test concentrations triggered the expression of the sulfonamide degrading enzymes (SadAB) and the modified target enzyme (Sul). Analysis of the functional proteins revealed increased cellular regulation and confirmed the bacterial strain's continued activity throughout the experiment. This suggests that at low SMX concentrations, even a highly sensitive and metabolically active strain may still require complementary enzymatic machinery to degrade potentially inhibitory metabolites. Thus, this study provides important insights into the persistence of SMX and reveals the complexities of antibiotic biodegradation at environmentally relevant concentrations, highlighting the need for comprehensive understanding of enzymatic mechanisms in micropollutant remediation strategies.

This pilot study evaluated a field-simulated bioremediation treatment for soils contaminated with military explosives as a precursor to a planned large-scale cleanup (~ 7,000,000 m²) in Israel. Sandy-loam soil was amended with compost and a microbial and managed under controlled irrigation and aeration for 85 days. HPLC analyzed six sampling rounds collected at defined intervals. Temporal changes in RDX, HMX, and TNT, commonly found at military sites and posing risks to human and environmental health, were assessed with LMMS and start-vs-end comparisons with non-parametric tests. Initial mean concentrations were 120.46 ± 34.54 mg kg⁻¹ (RDX), 144.73 ± 36.95 mg kg⁻¹ (TNT), and < LOQ for HMX. RDX and TNT declined sharply from day 55 onward and remained at or near non-detectable levels through day 85 (GLMM contrasts, all p < 0.001 after day 55); start-to-end differences corroborated these reductions (RDX: W = 12, p = 0.050; TNT: W = 12, p = 0.0319). HMX exhibited a non-monotonic pattern, increasing at day 40 (mean 4.66 ± 1.06 mg kg⁻¹) and decreasing thereafter, with a small residual at day 85 (0.12 ± 0.25 mg kg⁻¹; start-to-end W = 0.01, p = 0.0436). Overall, under field-simulated conditions, the treatment rapidly and sustainably reduced RDX and TNT. However, HMX showed greater variability and may require extended treatment or complementary measures. These quantitative pilot results inform the design and risk management of forthcoming full-scale remediation in similar semi-arid settings.

Hemp (Cannabis sativa L.) is a significant natural fibre employed as reinforcement in sustainable materials and, due to its considerable biomass, wide root system, and resilience to pollutants under harsh environments; it is an outstanding choice for the phytoremediation of multiple contaminants. This study aimed to assess hemp growth, gas exchange properties, antioxidant potential, and phytoremediation ability at varying concentrations of ciprofloxacin (0, 50, 100, 150, and 200 mg kg⁻¹) in a controlled glasshouse environment. The results indicate that hemp can tolerate Ciprofloxacin (CIP) concentrations up to 150 mg kg⁻¹ without substantial reductions in biomass and growth parameters; however, higher CIP levels, namely 200 mg kg⁻¹, lead to considerable drops in plant biomass and growth. The gas exchange properties and photosynthetic pigment levels of hemp leaves decreased as the CIP in the soil rose. Moreover, elevated CIP levels in soil induced lipid peroxidation via malondialdehyde level enhancement in hemp leaves. Elevated levels of CIP induced oxidative damage, antioxidants, including peroxidase and superoxide dismutase, function to neutralize ROS produced by oxidative stress. This study examined the CIP amounts in several plant elements such as fibres, stem core, leaves and roots at 4 different phases: 28-, 55-, 110- and 135-days post-sowing. The study’s findings reveal that, throughout the early growth stages, CIP predominantly accumulated in the subterranean regions of the crop, with limited translocation to the aerial areas. Conversely, at full maturity (135 days post-sowing), it was shown that the majority of CIP was translocated to the plant’s above-ground structures, with no accumulation in subterranean areas. The results demonstrate a progressive increase in CIP absorption in relation to heightened CIP concentrations in soil, suggesting that hemp could function as an effective phytoremediation bioresource and agent in contaminated soils.

High-density polyethylene (HDPE) significantly contributes to persistent environmental degradation due to its non-biodegradability and widespread usage. Bioremediation of plastic-contaminated sites by ubiquitous microbial agents appears to be an effective and safe alternative method for plastic waste disposal. This study investigated HDPE degradation by Brevibacillus parabrevis EVB 2 and Bacillus velezensis EVB8, isolated from cow fecal samples. The biodegradation test was assessed through colony-forming unit (CFU) counting, pH variation, residual weight loss (%), CO₂ emission measurements at 10-day intervals, and structural analysis using scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray diffraction (XRD), and Gas chromatography–mass spectrometry (GC–MS). EVB2 and EVB8 decreased the weight of HDPE films by 3.78 ± 0.90% and 1.84 ± 0.75%, respectively. Statistical analysis indicated that both reductions were significant compared to the control (p ≤ 0.05), with EVB2 showing the greatest weight loss and producing the highest CO₂ emission (104.42 ± 9.50 mg). SEM analysis indicated surface alterations in the treated films, including cracks and erosion, further validating the degradation by chemical changes and crystallinity levels detected through FTIR, XRD, and GC–MS analysis. This study demonstrates that the tested bacterial strains can achieve measurable HDPE biodegradation within 40 days without prior abiotic treatment, offering an efficient approach compared to previous studies that required pre-treatment or extended incubation periods. This work highlights the capacity of these strains to serve as effective microbial agents for HDPE biodegradation, supporting their application in the long term for sustainable plastic waste management.

This study evaluates the bioremediation potential of eight indigenous fungal strains isolated from chromium- and zinc-contaminated soils of the Korangi Industrial Estate, Karachi, Pakistan. The site, a major industrial hub hosting tanneries, metal plating, and chemical plants, has long suffered from heavy metal pollution due to untreated effluent discharge. To assess the remediation efficiency of these native fungi, bioleaching experiments were conducted under controlled ex-situ conditions using five nutrient media—Potato Dextrose Broth (PDB), Sabouraud Dextrose Broth (SDB), Yeast Peptone Dextrose (YPD), Yeast Peptone Glucose (YPG), and Czapek Dox Broth (CDB). Each 250 mL flask contained 100 mL of sterilized medium inoculated with 1 mL of spore suspension (≈10⁸ spores mL⁻¹) and 1 g of contaminated soil. Incubation was maintained at 32 °C, 150 rpm, and pH 6.5 for 144 h, with uninoculated controls to monitor abiotic metal release. Residual metal concentrations in the leachates were quantified by Atomic Absorption Spectroscopy (AAS). Uptake capacity (mg g⁻¹) was calculated based on the dry fungal biomass obtained after centrifugation and oven drying at 80 °C. Statistical analysis was performed using two-way ANOVA followed by Tukey’s post-hoc test (p < 0.05) to evaluate the effects of medium composition and fungal strain on bioleaching efficiency. Among all isolates, Aspergillus niger (K8) achieved the highest chromium removal (98.6%) with a maximum uptake of 0.3178 mg g⁻¹ in SDB, while Penicillium notatum (K1) exhibited superior zinc removal (94.5%) and uptake of 0.32 mg g⁻¹ in CDB. FTIR analysis confirmed that hydroxyl, amine, alkene, nitro, and tertiary alcohol functional groups on the fungal cell wall were actively involved in metal binding. SEM imaging further revealed hyphal curling and surface deformation after metal exposure, reflecting structural adaptation under stress. These findings demonstrate that indigenous fungal species are highly effective for the ex-situ removal of Cr and Zn from polluted soils. While laboratory-scale results are promising, future field-level applications must address pH sensitivity, fungal survival in native soils, and competition with existing microbiota. Nonetheless, A. niger (K8) and P. notatum (K1) represent potent, eco-friendly candidates for sustainable bioremediation and restoration of metal-contaminated industrial sites in Pakistan.

The growing contamination of terrestrial systems by heavy metals and organic pollutants is driving research towards sustainable and environmentally responsible remediation technologies. Engineered biochar, developed through physical, chemical, or biological modification, has recently emerged as an attractive, multifunctional platform to facilitate more effective soil remediation. Its customized surface characteristics, large sorption capacity, and stability in the environment provide the potential to both immobilize contaminants and facilitate positive exchanges with either native or inoculated microbial communities. Biochar–microbe systems not only enhance the bioavailability of contaminants for biodegradation and immobilization but also improve soil health by enriching microbial diversity, nutrient cycling, and carbon dynamics. The novelty of this review lies in its integrative evaluation of engineered biochar–microbe interactions as a climate-resilient remediation strategy, highlighting how synergistic mechanisms of adsorption, redox transformation, and biodegradation can outperform conventional remediation approaches. The need for this review arises from the lack of comprehensive assessments that integrate technological advancements (e.g., nanoparticle doping, surface oxidation, and microbial augmentation) with ecological perspectives, cost-effectiveness, and field-scale validation. We also discuss practical case studies that confirm the real-world efficacy of biochar–microbe systems and emphasize their dual role in soil detoxification and climate change mitigation through carbon sequestration and greenhouse gas reduction. This forward-looking synthesis provides a well-defined framework for advancing biochar–microbe systems as next-generation solutions for sustainable remediation.

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