Hydrogenophaga aromaticivorans sp. nov., isolated from a para-xylene-degrading enrichment culture, capable of degrading benzene, meta- and para-xylene

Abstract

A benzene, para- and meta-xylene-degrading Gram-stain-negative, aerobic, yellow-pigmented bacterium, designated as D2P1^T, was isolated from a para-xylene-degrading enrichment culture. Phylogenetic analyses based on 16S rRNA genes showed that D2P1^T shares a distinct phyletic lineage within the genus Hydrogenophaga and shows highest 16S rRNA gene sequence similarity to Hydrogenophaga taeniospiralis NBRC 102512^T (99.2 %) and Hydrogenophaga palleronii NBRC 102513^T (98.3 %). The draft genome sequence of D2P1^T is 5.63 Mb long and the genomic DNA G+C content is 65.5 %. Orthologous average nucleotide identity (OrthoANI) and digital DNA-DNA hybridization (dDDH) analyses confirmed low genomic relatedness to its closest relatives (OrthoANI <86 %; dDDH <30 %). D2P1^T contains ubiquinone 8 (Q-8) as the only respiratory quinone and phospholipid, phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol as major polar lipids. The main whole-cell fatty acids of D2P1^T are summed feature 3 (C_{16 : 1} ω7c/C_{16 : 1} ω6c), C_{16 : 0} and summed feature 8 (C_{18 : 1} ω7c/C_{18 : 1} ω6c). The polyphasic taxonomic results indicated that strain D2P1^T represents a novel species of the genus Hydrogenophaga, for which the name Hydrogenophaga aromaticivorans sp. nov. is proposed. The type strain is D2P1^T (=LMG 31780^T=NCAIM B 02655^T).

Keywords: Hydrogenophaga; aromatic hydrocarbons; biodegradation; groundwater.