Kurthia huakuii sp. nov., isolated from biogas slurry, and emended description of the genus Kurthia

Abstract

A novel facultatively anaerobic bacterium, designated strain LAM0618(T), was isolated from biogas slurry samples collected from the large-scale anaerobic digester of Modern Farming Corporation in Hebei Province, China. Cells of strain LAM0618(T) were Gram-stain-positive, motile, non-spore-forming and short-rod-shaped. The optimal temperature and pH for growth were 30 °C and 7.0, respectively. The strain did not require NaCl for growth but tolerated up to 70 g NaCl l(-1). The major fatty acids of strain LAM0618(T) were iso-C(15 : 0), anteiso-C(15 : 0), iso-C(14 : 0), C(16 : 0) and C(18 : 0). The predominant menaquinones of strain LAM0618(T) were menaquinone 7 (MK-7) and menaquinone 6 (MK-6). The main polar lipids of strain LAM0618(T) were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and six unknown glycolipids. The genomic DNA G+C content was 41 mol% as determined by the Tm method. Analysis of the 16S rRNA gene sequence revealed that strain LAM0618(T) was a member of the genus Kurthia, and was most closely related to 'Kurthia massiliensis' DSM 24639, Kurthia zopfii DSM 20580(T), Kurthia gibsonii DSM 20636(T) and Kurthia sibirica DSM 4747(T), with 96.9, 95.7, 95.6 and 94.9 % sequence similarity, respectively. Based on its phenotypic and genotypic properties, strain LAM0618(T) is suggested to represent a novel species of the genus Kurthia, for which the name Kurthia huakuii sp. nov. is proposed. The type strain is LAM0618(T) ( = ACCC 06121(T) = JCM 19187(T)).