Aug 2026· Journal of Agricultural and Food Chemistry· Vol 74 35, pp.
27779-27794
· 0 citations· 56 references
Medicine
TL;DR
Findings provide mechanistic insights into bacterial APAP biodegradation and highlight the practical application potential of strain DL27 and AdA, a novel amidase (AdA) identified through high-resolution mass spectrometry.
Abstract
The accumulation of acetaminophen (APAP) in agricultural soils and water systems poses risks to ecosystems and public health. This study characterizes Acinetobacter sp. DL27, an APAP-degrading strain with broad temperature and pH adaptability, demonstrating its bioremediation potential in soil and wastewater. Through high-resolution mass spectrometry, we identified three novel metabolic intermediates, thereby refining the bacterial APAP degradation pathway. Multiomics analysis elucidated metabolic coordination and stress-tolerance mechanisms, leading to the identification of a novel amidase (AdA). Recombinant AdA exhibited activity over 10-60 °C and pH 4.0-10.0, with a Km of 8.96 ± 1.03 μM and a kcat/Km of 9.04 μM-1s-1, indicating higher catalytic efficiency than previously reported APAP amidases. Molecular dynamics simulations and site-directed mutagenesis confirmed that a Ser161-Ser185-Lys82 triad constitutes the catalytic center driving amide cleavage. These findings provide mechanistic insights into bacterial APAP biodegradation and highlight the practical application potential of strain DL27 and AdA.
This study is the first to reveal the multienzyme mechanism of OTA degradation in the genus Pediococcus, providing a theoretical basis and genetic resources for probiotic- and enzyme-based bioremediation technologies.
Aflatoxin B1 (AFB1) is a highly toxic mycotoxin prevalent in food and feed that poses a grave threat to human and animal health. In this study, an AFB1- degrading strain of Arthrobacter citreus, designated Soilh02, was isolated. Under optimal conditions (37 °C, pH 8.0, 72 h), the presence of Cu2+ significantly enhanced AFB1 degradation, achieving a maximum degradation rate of 93.96%. Ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-QTOF) identified two novel degradation products with molecular formulas C18H 20O7 and C16H14O6, and proposed plausible structures for these compounds based on accurate mass data and fragmentation pathways. Subsequently, ultrafiltration, DE52 anion-exchange chromatography, activity assays, and SDS-PAGE were used to isolate and purify the extracellular proteins responsible for AFB1 degradation. LC-MS/MS and molecular docking analyses suggested that oxidoreductase RE1 may participate in AFB1 degradation, as its activity was markedly suppressed by inhibitors. RE1 bound AFB1 with a binding energy of -8.511 kcal/mol and was capable of degrading its difuran, lactone, and cyclopentenone ring via Lys-210, Arg-422, and Phe-427. Overall, this study provides a high-quality microbial resource and a theoretical basis for developing efficient and eco-friendly AFB1 biodegradation strategies. These findings offer significant potential for enhancing food and feed safety and promoting sustainable agricultural practice.
Chen Tian, Mengkai Liu, Xuan Guo et al.· Food Research International· 0 citations
Findings suggest that the studied FPMO may play a role in antibiotic resistance in P. aeruginosa by oxidatively inactivating ampicillin by oxidatively inactivating ampicillin.
Maliheh Mohammadkhani, Shamsozoha Abolmaali, S. D. Astaneh· Iranian Journal of Microbiol...· 0 citations
Nicosulfuron is a sulfonylurea herbicide with residues that pose ecological risks in agricultural soils. Here we elucidated the degradation mechanism of Enterobacter hormaechei ES1 through whole-genome sequencing, transcriptomics, metabolomics, gene knockout, heterologous expression, and soil bioremediation assays. Under nicosulfuron stress, ES1 upregulated antioxidant enzymes including SOD, POD, and CAT, along with glutathione synthesis, to scavenge excess reactive oxygen species. HPLC-TOF-MS identified degradation intermediates such as ADMP and ASDM, indicating initial cleavage of the sulfonylurea bridge. Integrated multi-omics prioritized Eh-fadB, encoding a fatty acid β-oxidation multifunctional enzyme, as a novel degradative gene. Targeted knockout of Eh-fadB reduced nicosulfuron degradation from 87.6% to 37.04%, while genetic complementation restored nearly full activity. Purified Eh-FadB directly converted nicosulfuron, with optimal performance at 30 °C and pH 5-6; its activity was enhanced by Na+ and Pb2+ but inhibited by Fe3+. Molecular docking and dynamics identified His-450 and Asn-427 as key residues for substrate binding. In contaminated soil, inoculation with ES1 reduced nicosulfuron content within 21 days and promoted recovery of dehydrogenase and urease activities. This study provides the first genetic and biochemical evidence that a FadB-type enzyme participates in nicosulfuron catabolism, supporting sulfonylurea bridge cleavage and its potential for soil bioremediation.
Xian Wu, Kuo Liu, Yu-Lin Wu et al.· Journal of Hazardous Materia...· 0 citations
Pyrethroid residues in tea have emerged as a significant safety concern due to their high lipophilicity and persistence, while efficient and mild enzymatic removal resources remain scarce. In this study, two novel esterase genes, gene3341 and gene2566, were identified from Lysinibacillus pakistanensis VF-2, both belonging to the α/β-hydrolase superfamily with a typical catalytic triad and conserved Gly-X-Ser-X-Gly motif. The recombinant enzymes Est3341 and Est2566 were successfully expressed in Escherichia coli, and exhibited β-cypermethrin (β-CY) degradation efficiencies of 77.97% and 71.92% within 7 days, respectively. Biochemical characterization demonstrated that Est3341 was a cold-adapted esterase with optimal activity at 25 °C and pH 7.0, enabling efficient degradation under mild conditions suitable for heat-sensitive tea matrices. Notably, Est3341 degraded 98.68% of high-concentration β-CY within 36 h, and its activity was significantly enhanced by Ca2+ and Mn2+. In tea leaf application, Est3341 removed 55.01% of β-CY, 59.40% of cypermethrin, and 46.23% of deltamethrin residues within 20 min at 25 °C. GC-MS analysis revealed that Est3341 hydrolyzed β-CY's ester bonds to yield 3-phenoxybenzaldehyde and other characteristic intermediates. This study provides a high-efficiency, mild-condition, tea-adapted esterase resource for green removal of pyrethroid residues in agricultural products, offering a promising strategy for food safety and environmental bioremediation.
Wan-Ting Wang, Hu Zhou, Jie Tang et al.· Pesticide Biochemistry and P...· 0 citations
Aflatoxin B1 (AFB1) is one of the most toxic mycotoxins, widely contaminating agricultural products and posing a serious threat to food safety and human health. Enzymatic degradation is considered a promising detoxification strategy due to its high efficiency, strong specificity, and lack of secondary pollution. AKR13B3, a member of the aldo-keto reductase family, possesses intrinsic catalytic activity for AFB1 degradation; however, its low natural activity severely limits practical application. In this study, the binding mode of the AKR13B3-NADPH complex with AFB1 was first determined using AlphaFold 3.0 and AutoDock Vina. Through interaction analysis, Trp102 and Asp41 were identified as key targets for enhancing catalytic activity. Following site-directed mutagenesis screening, two mutants, D41H and D41T, with significantly improved catalytic activity were obtained, exhibiting 52.32% and 46.44% higher activity than the wild-type enzyme, respectively. Three-dimensional structural simulation revealed that D41H and D41T form stable interactions with the carbonyl group on the lactone ring of AFB1, thereby polarizing the carbonyl group and reducing the activation energy of the reaction, ultimately enhancing catalytic activity. Substrate channel analysis demonstrated that, compared with the wild-type, the D41H and D41T mutants significantly increased the bottleneck radius of the substrate channel (by 25% and 22%, respectively) and shortened the channel length (by 23% and 33%, respectively), thereby partially relieving steric hindrance and diffusion limitations and improving catalytic efficiency. In summary, this study elucidates the molecular basis by which D41H and D41T enhance the catalytic activity of AKR13B3 toward AFB1 through the dual mechanisms of external/hydrogen bond catalysis and channel remodeling, providing an important theoretical foundation for the rational design and directed engineering of AFB1-degrading enzymes.
Qing-Wei Jiang, Juan Shen, Zhang-Hu Chen et al.· International Journal of Mol...· 0 citations
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