Biodegradation最新文献

Biodegradation has been the most sought method for degradation of various xenobiotic contamination including crude oil contamination, but it has shown limited efficiency due to the hydrophobic property of the crude oil. In order to overcome this drawback, microbial species along with minerals having ability to adsorb oil onto its surface can be used to increase its availability. In this study, an attempt to increase the bioavailability of the crude oil by adsorption by addition of the oil degrading microorganisms to the ex-situ system was performed to determine efficiency. Firstly, the study involved the synthesis and characterization of the nanoparticles obtained from calcium carbonate shells of Semibalanus balanoides (Acorn Barnacles), and the isolation of Paenibacillus dentritiformis (a Gram-positive bacterium) for production of oil mineral aggregate (OMA). The synthesized calcite nanoparticles were characterized using XRD, FTIR, ZETA Sizer and Potential, HR- SEM, EDS, HR-TEM. The structural analysis showed that the OMA was larger in size compared to cuboidal nanoparticles at 500 nm. Further, the degradation potential of the OMA was comparatively more at 88% and the biodegradation potential of P. dentritiformis was 67% when compared to the control. These results suggested that the change in the surface morphology of the nanoparticles by the formation of OMA reduced the hydrophobicity of the crude oil, thereby increasing its bioavailability for enhanced degradation.

Graphical abstract

The discharge of synthetic azo dyes such as Congo Red (CR) and Methyl Orange (MO) from textile industries poses severe threats to aquatic ecosystems and human health due to their toxicity, stability, and resistance to conventional treatment methods. The study investigates the decolorization potential of a thermophilic bacterium, Bacillus haynesii ING6, isolated from Tuva-Timba hot springs, for simultaneous degradation of CR and MO. Optimization of process parameters, including pH, dye concentration, temperature, inoculum size, and sugar concentration, was performed using Response Surface Methodology (RSM) with Central Composite Design (CCD). The quadratic polynomial models developed for both dyes were statistically significant, with high coefficients of determination (R² = 0.9939 for CR and 0.9952 for MO) and non-significant lack-of-fit values. ANOVA confirmed that pH, dye concentration, and temperature were the key factors significantly influencing degradation efficiency. Response surface plots revealed strong interactive effects among parameters, with maximum degradation efficiencies achieved at pH 8, 50 mg/L dye concentration, 55 °C, 5% inoculum, and 3% sugar. Under optimized conditions, Bacillus haynesii ING6 accomplished 95.23% CR removal and 96.29% MO removal. These findings provide the first report of azo dye degradation by Bacillus haynesii ING6, highlighting its potential as a sustainable bioremediation agent for textile wastewater treatment.

Per- and polyfluoroalkyl substances (PFAS), as emerging contaminants with extreme persistence and bioaccumulation, threaten microbially mediated nitrogen removal in wastewater systems. This study systematically reviewed multiscale response mechanisms under PFAS stress, from molecular interfaces to community function. The distribution of PFAS across water, sludge, and sediments was summarized first, with short-chain PFASs observed to have increased mobility owing to their higher aqueous solubility. Second, the dual effects of PFAS were elucidated: low concentrations (< 100 μg/L) temporarily enhanced nitrogen removal by promoting extracellular polymeric substances (EPS) and transiently activating genes (e.g., nosZ), whereas high concentrations (> 50 mg/L) inhibited key genes (amoA, hzsB), reduced the activity of ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB), and anaerobic ammonium-oxidizing bacteria (AnAOB), and impair nitrogen removal efficiency. PFAS also reshaped microbial communities, enriching tolerant taxa (e.g., Proteobacteria, Firmicutes) and suppressing sensitive groups (e.g., Nitrospira). Mechanistically, PFASs disrupted cell membranes, inhibited metabolic enzymes, and induced reactive oxygen species (ROS) accumulation, which damaged catalytic sites of enzymes (Nar, Nir, Nos) and caused DNA damage. Effects of short-chain and emerging PFASs (F-53B, 6:2 FTS) across concentration ranges were integrated, and a multiscale action model was proposed comprising: (1) molecular-interface disruption, (2) gene regulation, and (3) community functional reshaping. Critical research gaps were identified, including low-dose chronic exposure, co-contaminant synergies, and coupled remediation using functional consortia or engineered materials, addressing these gaps was expected to inform PFAS ecological risk assessment and management optimization.

Graphical Abstract

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.