Sphingomonas chloroacetimidivorans sp. nov., a chloroacetamide herbicide-degrading bacterium isolated from activated sludge.

Abstract

Strain Y1(T), a Gram-negative, non-spore-forming, rod-shaped bacterium, was isolated from activated sludge. This strain is able to degrade several commonly used chloroacetamide herbicides, such as butachlor, acetochlor and alachlor. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain Y1(T) is a member of the genus Sphingomonas and shows high sequence similarities with S. starnbergensis 382(T) (95.7 %), S. sanxanigenens NX02(T) (95.7 %) and S. haloaromaticamans A175(T) (95.3 %), and shows low (<95 %) sequence similarities to all other Sphingomonas species. Chemotaxonomic analysis revealed that strain Y1(T) possesses Q-10 as the predominant ubiquinone, C14:0 2-OH as the major 2-hydroxy fatty acid and sym-homospermidine as the major polyamine. The main cellular fatty acids of strain Y1(T) were found to be C18:1 ω7c (38.2 %), C16:1 ω6c/C16:1 ω7c (28.5 %), C16: 0 (10.7 %) and C14:0 2-OH (14.3 %). The main polar lipids were determined to be diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, sphingoglycolipids (SGL1-SGL3), phosphatidyl dimethylethanolamine and aminophospholipid. The DNA G+C content was found to be 66 ± 0.4 mol%. Based on phylogenetic analysis, phenotypic characteristics and chemotaxonomic data, strain Y1(T) is considered to represent a novel species of the genus Sphingomonas, for which the name Sphingomonas chloroacetimidivorans sp. nov. is proposed. The type strain is Y1(T) (=CCTCC AB 2011178(T) = KACC 16607(T)).