Diaphorobacter polyhydroxybutyrativorans sp. nov., a novel poly(3-hydroxybutyrate-co-3-hydroxyvalerate)-degrading bacterium isolated from biofilms

A novel Gram-stain-negative, facultatively aerobic and rod-shaped strain, designated SL-205(T), was isolated from the biofilms of a denitrifying reactor using poly(3-hydoxybutyrate-co-3-hydroxyvalerate) as the sole carbon source in Beijing, PR China. A polyphasic taxonomic characterization was performed on the novel isolate. Phylogenetic analyses based on the 16S rRNA gene sequence revealed that strain SL-205(T) is a member of the genus Diaphorobacter. High levels of 16S rRNA gene sequence similarity were found between strain SL-205(T) and Diaphorobacter nitroreducens NA10B(T) (99.4%) and Diaphorobacter oryzae RF3(T) (98.5%), respectively. However, the DNA-DNA relatedness values between strain SL-205(T) and D. nitroreducens NA10B(T) and D. oryzae RF3(T) were 57 ± 1% and 45 ± 1.5%, respectively. The G+C content of the genomic DNA of strain SL-205(T) was 66.8 mol%. The major fatty acids consisted of summed feature 3 (including C16 : 1ω7c and/or iso-C15 : 0 2-OH), C16 : 0 and C18 : 1ω7c. Ubiquinone Q-8 was the only respiratory quinone; the polar lipid profile comprised phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and one uncharacterized phospholipid. We conclude that strain SL-205(T) represents a novel species of the genus Diaphorobacter for which the name Diaphorobacter polyhydroxybutyrativorans is proposed; the type strain is SL-205(T) ( = ACCC 19739(T) = DSM 29460(T)).