Pelorhabdus rhamnosifermentans gen. nov., sp. nov., a strictly anaerobic rhamnose degrader from freshwater lake sediment

A rhamnose-degrading bacterium, strain BoRhaAT, was isolated from profundal sediment of Lake Constance in agar dilution series with L-rhamnose as substrate and with a background lawn of Methanospirillum hungatei. The isolated strain was a motile rod that stained Gram positive. Growth was observed within a pH range of 4.0–7.5 and a temperature range of 15–30°C. Fermentation products of rhamnose or glucose were acetate, propionate, ethanol, butyrate, and 1-propanol. The G+C content was 40.6% G+C. The dominant fatty acids are C16:1ω9c, i-C13:03OH, C16:0 and C17:1ω8c with 8–21% relative abundance. Polar lipids were glycolipids, phosphatidylethanolamine, phosphoaminolipid and other lipids, of which phosphatidylethanolamine was most abundant. The sequence of the 16S rRNA gene of the new isolate matches the sequence of its closest relative Anaerosporomusa subterranea to 92.4%. A comparison of the genome with this strain showed 60.2% genome-wide average amino acid identity (AAI), comparisons with other type strains showed a maximum of 62.7% AAI. Thus, the definition of a new genus is justified for which we propose the name Pelorhabdus. For strain BoRhaAT, we propose the name Pelorhabdus rhamnosifermentans gen. nov., sp. nov., with strain BoRhaAT (DSM 111565T = JCM 39158T) as the type strain.