Cohnella xylanilytica sp. nov. and Cohnella terrae sp. nov., xylanolytic bacteria from soil

Abstract

Two xylan-degrading bacteria, strains MX15-2(T) and MX21-2(T), were isolated from soils collected in Nan province, Thailand. Cells were Gram-reaction-positive, facultatively anaerobic, spore-forming and rod-shaped. They contained meso-diaminopimelic acid in the cell-wall peptidoglycan. The major menaquinone was MK-7. iso-C(16 : 0) and anteiso-C(15 : 0) were the predominant cellular fatty acids. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and lysyl-phosphatidylglycerol were the major polar lipids. The genomic DNA G+C contents of strains MX15-2(T) and MX21-2(T) were 63.0 and 65.1 mol%, respectively. Phylogenetic analysis using 16S rRNA gene sequences showed that strains MX15-2(T) and MX21-2(T) were affiliated with the genus Cohnella and were closely related to Cohnella thermotolerans CCUG 47242(T), with 96.5 and 95.6 % sequence similarity, respectively. The strains could be clearly distinguished from each other and from all known species of the genus Cohnella based on their physiological and biochemical characteristics as well as their phylogenetic positions and levels of DNA-DNA hybridization. Therefore, these two strains represent novel species of the genus Cohnella, for which the names Cohnella xylanilytica sp. nov. (type strain MX15-2(T) =KCTC 22294(T) =PCU 309(T) =TISTR 1891(T)) and Cohnella terrae sp. nov. (type strain MX21-2(T) =KCTC 22295(T) =PCU 310(T) =TISTR 1892(T)) are proposed.