Brassicibacter mesophilus gen. nov., sp. nov., a strictly anaerobic bacterium isolated from food industry wastewater

Abstract

A novel mesophilic, strictly anaerobic bacterium, strain BMT, was isolated from food industry wastewater. The cells were motile, non-spore-forming rods and stained Gram-negative. Growth of strain BMT was observed at 16–44 °C (optimum 37 °C) and pH 6.0–9.0 (optimum pH 7.5). The NaCl concentration range for growth was 0–8 % (optimum 1.5 %, w/v). Strain BMT was chemo-organotrophic, using a few sugars and amino acids as sole carbon and energy sources. The fermentation products from peptone-yeast extract broth were propionate, formate, acetate, ethanol and isovalerate. Indole, NH3 and H2S were produced from peptone. No respiratory quinones could be detected. The major fatty acids were iso-C15 : 0 (39.3 %), iso-C15 : 0 dimethyl acetal (10.1 %), anteiso-C15 : 0 (7.6 %), C14 : 0 (6.1 %) and C16 : 0 (5.6 %). The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol and a number of unidentified aminoglycolipids, glycolipids and phospholipids. The DNA G+C content was 28.2 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain BMT was related to various genera of the family Clostridiaceae , and its closest relatives were Sporosalibacterium faouarense SOL3f37T (94.3 % 16S rRNA gene sequence similarity), Proteiniborus ethanoligenes GWT (92.1 %) and Clostridiisalibacter paucivorans 37HS60T (92.0 %). In recognition of its distinct phenotypic and genotypic characteristics, isolate BMT is proposed to represent a novel species of a new genus, Brassicibacter mesophilus gen. nov., sp. nov. The type strain of Brassicibacter mesophilus is BMT ( = JCM 16868T  = DSM 24659T).