title: Biodegradation and metabolic pathway of β-chlorinated aliphatic acid in Bacillus sp. CGMCC no. 4196.
abstract: In this study, a bacterial Bacillus sp. CGMCC no. 4196 was isolated from mud. This strain exhibited the ability to degrade high concentration of 3-chloropropionate (3-CPA, 120 mM) or 3-chlorobutyrate (30 mM), but not chloroacetate or 2-chloropropionate (2-CPA). The growing cells, resting cells, and cell-free extracts from this bacterium had the capability of 3-CPA degradation. The results indicated that the optimum biocatalyst for 3-CPA biodegradation was the resting cells. The 3-CPA biodegradation pathway was further studied through the metabolites and critical enzymes analysis by HPLC, LC-MS, and colorimetric method. The results demonstrated that the metabolites of 3-CPA were 3-hydroxypropionic acid (3-HP) and malonic acid semialdehyde, and the critical enzymes were 3-CPA dehalogenase and 3-HP dehydroxygenase. Thus, the mechanism of the dehalogenase-catalyzed reaction was inferred as hydrolytic dehalogenation which was coenzyme A-independent and oxygen-independent. Finally, the pathway of β-chlorinated aliphatic acid biodegradation could be concluded as follows: the β-chlorinated acid is first hydrolytically dehalogenated to the β-hydroxyl aliphatic acid, and the hydroxyl aliphatic acid is oxidized to β-carbonyl aliphatic acid by β-hydroxy aliphatic acid dehydroxygenase. It is the first report that 3-HP was produced from 3-CPA by β-chlorinated aliphatic acid dehalogenase.
authors.affiliation: Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Chunjiao
authors.initials: C
authors.lastname: Lin
authors.forename: Lirong
authors.initials: L
authors.lastname: Yang
authors.forename: Gang
authors.initials: G
authors.lastname: Xu
authors.forename: Jianping
authors.initials: J
authors.lastname: Wu
mesh_terms: D001407:Bacillus / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002851:Chromatography, High Pressure Liquid; D005285:Fermentation; D054879:Halogenation; D006843:Hydrocarbons, Chlorinated; D053858:Metabolic Networks and Pathways; D010088:Oxidoreductases / Q000378:metabolism; D011422:Propionates / Q000378:metabolism*
chemical_list: D006843:Hydrocarbons, Chlorinated; D011422:Propionates; C021974:2-chloropropionic acid; D010088:Oxidoreductases; C007022:3-chloropropionic acid