Parapedobacter pyrenivorans sp. nov., isolated from a pyrene-degrading microbial enrichment, and emended description of the genus Parapedobacter

Abstract

A novel pyrene-degrading, Gram-negative bacterium, designated strain P-4T, was isolated from a polycyclic aromatic hydrocarbon-degrading enrichment of polluted soils from a coking chemical plant. Cells of strain P-4T were non-motile rods. Strain P-4T grew at 15–45 °C (optimum, 37 °C), pH 6.0–10.0 (optimum, pH 8.5) and 0–4 % (w/v) NaCl. Analysis of the 16S rRNA gene sequence showed that strain P-4T was related phylogenetically to members of the genus Parapedobacter , with sequence similarity of 93.7–95.1 %. The cellular fatty acids of strain P-4T were iso-C15 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), iso-C17 : 0 3-OH, summed feature 9 (iso-C17 : 1ω9c and/or 10-methyl C16 : 0 ), anteiso-C15 : 0, iso-C15 : 0 3-OH, C16 : 0, iso-C15 : 1 G, C16 : 0 3-OH and C17 : 0 2-OH. Cells contained menaquinone 7 as the major quinone. The polyamine of strain P-4T was homospermidine, and the main polar lipids were phosphatidylethanolamine and a sphingolipid. The G+C content of the DNA was 45.4 mol%. Strain P-4T showed a range of phenotypic characteristics that differentiated it from previously recognized Parapedobacter species, particularly its ability to use pyrene as a sole carbon source for growth and its alkaline optimal pH for growth (pH 8.5). On the basis of these results, it is concluded that strain P-4T represents a novel species of the genus Parapedobacter , for which the name Parapedobacter pyrenivorans (type strain P-4T = NBRC 109113T = CGMCC 1.12195T) is proposed. An emended description of the genus Parapedobacter is also provided.