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

A rhamnose-degrading bacterium, strain BoRhaA(T), 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 degrees 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 C-16:(1)omega 9c, i-C(13)(: 0)3OH, C-16(.0) and C-17(:1 )omega 8c 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 BoRhaA T , we propose the name Pelorhabdus rhamnosifermentans gen. nov., sp. nov., with strain BoRhaA(T) (DSM 111565(T) = JCM 39158(T)) as the type strain. (C) 2021 The Authors. Published by Elsevier GmbH.

Automated summary

In this study, a rhamnose-degrading bacterium isolated from profundal sediment of Lake Constance was identified as a new genus Pelorhabdus. The strain exhibited growth at pH 4.0-7.5 and temperature range of 15-30 degrees C, with fermentation products including acetate, propionate, ethanol, butyrate, and 1-propanol. Genomic comparisons suggested a distinct identity warranting the proposal of the new genus Pelorhabdus and species Pelorhabdus rhamnosifermentans gen. nov., sp. nov.