Cohnella baijiui sp. nov., a cellulolytic bacterium isolated from fermented grains of baijiu.

Abstract

A Gram-stain-positive, rod-shaped, motile bacterium, strain REN36T, was isolated from fermented grains of baijiu. The optimal growth conditions for this organism were observed at a salt concentration of 0% (with a tolerance range of Sodium chloride (NaCl) from 0% to 2%), a temperature of 37 °C (with a tolerance range from 20 to 45 °C) and a pH of 6.0 (with a tolerance range from pH 4.0 to 8.0). The 16S rRNA gene sequence of the isolate showed 98.04% similarity to Cohnella nanjingensis D45T. The predominant respiratory quinone identified was menaquinone 7, while anteiso-C15:0 and C16:0 were the major fatty acids. The polar lipid profile of strain REN36T included diphosphatidylglycerol, phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, four aminophospholipids, two phospholipids, one glycolipid, one aminoglycolipid, one aminolipid and seven lipids. The DNA G+C content was 58.8 mol%. Notably, strain REN36T exhibited cellulolytic activity: it utilizes sodium carboxymethyl cellulose as the sole carbon source and encoded three endoglucanases [glycoside hydrolase family 5 (GH5)/GH9] that synergistically degrade cellulose. Digital DNA-DNA hybridization of the isolate with two reference strains showed relatedness values of 29.2% with C. nanjingensis DSM 28246T and 21.6% with Cohnella ginsengisoli DSM 18997T. The phylogenetic, chemotaxonomic and phenotypic data supported the classification of strain REN36T as a representative of a novel species within the genus Cohnella, for which the name Cohnella baijiui sp. nov. is proposed. The type strain is REN36T (=GDMCC 1.2866T=JCM 35185T).