Description of Sphingosinicella xenopeptidilytica sp. nov., a β-peptide-degrading species, and emended descriptions of the genus Sphingosinicella and the species Sphingosinicella microcystinivorans

Abstract

A Gram-negative, rod-shaped bacterium, strain 3-2W4T, was isolated from the aeration tank of a wastewater treatment plant in Zurich and was found to have the exceptional capacity to degrade synthetic β-peptides. 16S rRNA gene sequence analysis showed that strain 3-2W4T is closely related to Sphingosinicella microcystinivorans Y2T, but DNA–DNA hybridization experiments between these two strains revealed that they belong to two different species. The two strains displayed different fingerprints after PCR analysis using the repetitive primers BOX, ERIC and REP. Strain 3-2W4T did not degrade microcystin, which is a characteristic trait of Sphingosinicella microcystinivorans Y2T. Like Sphingosinicella microcystinivorans Y2T, strain 3-2W4T had the following characteristics: fatty acids comprising mainly C18 : 1 ω7c, summed feature 3 (C16 : 1 ω7c and/or iso-C15 : 0 2-OH) and C16 : 0, the presence of ubiquinone Q-10 and sym-homospermidine as the predominant polyamine compound. The polar lipid profiles of the two strains were almost identical, consisting of phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol and sphingoglycolipid. Strain 3-2W4T and Sphingosinicella microcystinivorans Y2T utilized the β-peptides H-βhVal-βhAla-βhLeu-OH and H-βhAla-βhLeu-OH as sole carbon and energy sources and shared β-peptidyl aminopeptidase activity in common, which distinguishes them from Sphingomonas and Sphingopyxis type strains. On the basis of these results, strain 3-2W4T represents a novel species of the genus Sphingosinicella, for which the name Sphingosinicella xenopeptidilytica sp. nov. is proposed. The type strain is 3-2W4T (=DSM 17130T=CCUG 52537T). The descriptions of the genus Sphingosinicella and the species Sphingosinicella microcystinivorans are emended.