Paracoccus huijuniae sp. nov., an amide pesticide-degrading bacterium isolated from activated sludge of a wastewater biotreatment system

Abstract

A facultatively anaerobic, non-spore-forming, non-motile, catalase- and oxidase-positive, Gram-reaction-negative, coccoid to short rod-shaped strain, designated FLN-7(T), was isolated from activated sludge of a wastewater biotreatment facility. The strain was able to hydrolyse amide pesticides (e.g. diflubenzuron, propanil, chlorpropham and dimethoate) through amide bond cleavage. Strain FLN-7(T) grew at 4-42 °C (optimum 28 °C), at pH 5.0-8.0 (optimum pH 7.0) and with 0-5.0 % (w/v) NaCl (optimum 1.0 %). The major respiratory quinone was ubiquinone-10. The major cellular fatty acid was C18 : 1ω7c. The genomic DNA G+C content of strain FLN-7(T) was 66.4±0.5 mol%. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylcholine and an unidentified glycolipid. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain FLN-7(T) was a member of the genus Paracoccus and showed highest 16S rRNA gene sequence similarities with Paracoccus aminovorans JCM 7685(T) (99.2 %), P. denitrificans DSM 413(T) (97.8 %), P. yeei CDC G1212(T) (97.3 %) and P. thiocyanatus THI 011(T) (97.1 %). Strain FLN-7(T) showed low DNA-DNA relatedness with P. aminovorans KACC 12261(T ()36.5±3.4 %), P. denitrificans KACC 12251(T) (30.5±2.6 %), P. yeei CCUG 46822(T) (26.2±2.4 %) and P. thiocyanatus KACC 13901(T) (15.5±0.9 %). Based on the phylogenetic analysis, DNA-DNA hybridization, whole-cell fatty acid composition and biochemical characteristics, strain FLN-7(T) was clearly distinguished from all recognized species of the genus Paracoccus and should be classified in a novel species, for which the name Paracoccus huijuniae sp. nov. is proposed. The type strain is FLN-7(T) ( = KACC 16242(T) = ACCC 05690(T)).