Biodegradation of nicosulfuron by a novel Alcaligenes faecalis strain ZWS11.
A bacterial strain ZWS11 was isolated from sulfonylurea herbicide-contaminated farmland soil and identified as a potential nicosulfuron-degrading bacterium. Based on morphological and physicochemical characterization of the bacterium and phylogenetic analysis of the 16S rRNA sequence, strain ZWS11 was identified as Alcaligenes faecalis. The effects of the initial concentration of nicosulfuron, inoculation volume, and medium pH on degradation of nicosulfuron were investigated. Strain ZWS11 could degrade 80.56% of the initial nicosulfuron supplemented at 500.0mg/L under the conditions of pH7.0, 180r/min and 30°C after incubation for 6days. Strain ZWS11 was also capable of degrading rimsulfuron, tribenuron-methyl and thifensulfuron-methyl. Four metabolites from biodegradation of nicosulfuron were identified, which were 2-aminosulfonyl-N, N-dimethylnicotinamide (M1), 4, 6-dihydroxypyrimidine (M2), 2-amino-4, 6-dimethoxypyrimidine (M3) and 2-(1-(4,6-dimethoxy-pyrimidin-2-yl)-ureido)-N,N-dimethyl-nicotinamide (M4). Among the metabolites detected, M2 was reported for the first time. Possible biodegradation pathways of nicosulfuron by strain ZWS11 were proposed. The degradation proceeded mainly via cleavage of the sulfonylurea bridge, O-dealkylation, and contraction of the sulfonylurea bridge by elimination of a sulfur dioxide group. The results provide valuable information for degradation of nicosulfuron in contaminated environments.
College of Science, China Agricultural University, Beijing 100193, China. Electronic address: zhaoweisong1985@163.com.
Weisong
W
Zhao
College of Science, China Agricultural University, Beijing 100193, China.
Chen
C
Wang
College of Science, China Agricultural University, Beijing 100193, China.
Li
L
Xu
College of Science, China Agricultural University, Beijing 100193, China.
Chunqing
C
Zhao
College of Science, China Agricultural University, Beijing 100193, China.
Hongwu
H
Liang
College of Science, China Agricultural University, Beijing 100193, China. Electronic address: lihongqiuyang@126.com.
Lihong
L
Qiu
D042481:Alcaligenes faecalis / Q000235:genetics / Q000378:metabolism*; D001673:Biodegradation, Environmental; D006540:Herbicides / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011725:Pyridines / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D012989:Soil Pollutants / Q000378:metabolism*; D013453:Sulfonylurea Compounds / Q000378:metabolism*
D006540:Herbicides; D011725:Pyridines; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D013453:Sulfonylurea Compounds; C416723:nicosulfuron
Alcaligenes faecalis; Biodegradation; Metabolite; Nicosulfuron