Biodegradation of pendimethalin by Bacillus subtilis Y3

• Published in: Journal of environmental sciences (China) 2016-03, Vol.41 (3), p.121-127
• Main Authors: Ni, Haiyan, Yao, Li, Li, Na, Cao, Qin, Dai, Chen, Zhang, Jun, He, Qin, He, Jian
• Format: Article
• Language: English
• Subjects: Aniline Compounds - metabolism; Bacillus sp. Y3; Bacillus subtilis; Bacillus subtilis - classification; Bacillus subtilis - genetics; Bacillus subtilis - isolation & purification; Bacillus subtilis - metabolism; Biodegradation; Biodegradation, Environmental; Chromatography, High Pressure Liquid; Environmental Monitoring; Herbicides - metabolism; Metabolic pathway; Nitroreductase; Pendimethalin; Phylogeny; RNA, Bacterial - genetics; RNA, Ribosomal, 16S - genetics; rRNA基因; Sewage - microbiology; Tandem Mass Spectrometry; 微生物量; 枯草芽孢杆菌; 烟酰胺腺嘌呤二核苷酸; 生物降解; 系统发育分析; 芳香硝基化合物; 高效液相色谱-串联质谱
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/j.jes.2015.04.035

A bacterium strain Y3,capable of efficiently degrading pendimethalin,was isolated from activated sludge and identified as Bacillus subtilis according to its phenotypic features and 16 S rRNA phylogenetic analysis.This strain could grow on pendimethalin as a sole carbon source and degrade 99.5%of 100 mg/L pendimethalin within 2.5 days in batch liquid culture,demonstrating a greater efficiency than any other reported strains.Three metabolic products,6-aminopendimethalin,5-amino-2-methyl-3-nitroso-4-（pentan-3-ylamino） benzoic acid,and 8-amino-2-ethyl-5-（hydroxymethyl）-1,2-dihydroquinoxaline-6-carboxylic acid,were identified by HPLC-MS/MS,and a new microbial degradation pathway was proposed.A nitroreductase catalyzing nitroreduction of pendimethalin to 6-aminopendimethalin was detected in the cell lysate of strain Y3.The cofactor was nicotinamide adenine dinucleotide phosphate（NADPH） or more preferably nicotinamide adenine dinucleotide（NADH）.The optimal temperature and pH for the nitroreductase were 30℃ and 7.5,respectively.Hg~（2＋）,Ni~（2＋）,Pb~（2＋）,Co~（2＋）,Mn~（2＋） Cu~（2＋）,Ag~＋,and EDTA severely inhibited the nitroreductase activity,whereas Fe~（2＋）,Mg~（2＋）,and Ca~（2＋） enhanced it.This study provides an efficient pendimethalin-degrading microorganism and broadens the knowledge of the microbial degradation pathway of pendimethalin.