title: Biodegradation of pendimethalin by Bacillus subtilis Y3.
abstract: 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 16S rRNA phylogenetic analysis. This strain could grow on pendimethalin as a sole carbon source and degrade 99.5% of 100mg/L pendimethalin within 2.5days 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°C 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.
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Life Sciences College of Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Ni
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Life Sciences College of Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Li
authors.initials: L
authors.lastname: Yao
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Life Sciences College of Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.affiliation: China National Center for Biotechnology Development, Beijing 100039, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Cao
authors.affiliation: College of Life Sciences, Laboratory Centre of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Dai
authors.affiliation: Key Laboratory of Plant Nutrition and Fertilization in Low-Middle Reaches of the Yangtze River, Ministry of Agriculture, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Life Sciences College of Nanjing Agricultural University, Nanjing 210095, China. Electronic address: qhe@njau.edu.cn.
authors.forename: Qin
authors.initials: Q
authors.lastname: He
authors.affiliation: Key Laboratory of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, Life Sciences College of Nanjing Agricultural University, Nanjing 210095, China; College of Life Sciences, Laboratory Centre of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China. Electronic address: hejian@njau.edu.cn.
authors.forename: Jian
authors.initials: J
authors.lastname: He
mesh_terms: D000814:Aniline Compounds / Q000378:metabolism*; D001412:Bacillus subtilis / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002851:Chromatography, High Pressure Liquid; D004784:Environmental Monitoring; D006540:Herbicides / Q000378:metabolism*; D010802:Phylogeny; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000382:microbiology; D053719:Tandem Mass Spectrometry
chemical_list: D000814:Aniline Compounds; D006540:Herbicides; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; D012722:Sewage; C030856:pendimethalin
keywords: Bacillus sp. Y3; Biodegradation; Metabolic pathway; Nitroreductase; Pendimethalin