Clostridium arbusti sp. nov., an anaerobic bacterium isolated from pear orchard soil

Abstract

An obligately anaerobic, Gram-positive, spore-forming bacterial strain, designated SL206T, was isolated from pear orchard soils. Strain SL206T cells were straight or slightly curved rods, with motility by peritrichate flagella. Cell walls contained meso-diaminopimelic acid; wall sugars were glucose, rhamnose and mannose. The major fatty acids were C 16 : 0, C18 : 1ω9c and summed feature 10 (containing C18 : 1ω11c/9t/6t). API 20A reactions were negative for oxidase, catalase and acid production from L-rhamnose, sucrose, trehalose, D-xylose, melezitose, salicin and D-sorbitol, and positive for acid production from D-glucose, sucrose, maltose, D-mannose and raffinose. Glucose was fermented to acetate, butyrate, CO2, H2 and ethanol in culture. The G+C content of the genomic DNA was 31.1 mol%. Based on comparative 16S rRNA gene sequence analysis, the isolate belonged to the genus Clostridium and formed a clade with Clostridium pasteurianum. The species most closely related to strain SL206T were C. pasteurianum (98.6% similarity) and Clostridium acidisoli (97.8% similarity). In DNA-DNA relatedness studies, the isolate had 59.5% relatedness with C. pasteurianum and thus represented a unique species. On the basis of these studies, strain SL206T (=KCTC 5449T =JCM 14858T) is proposed to represent the type strain of a novel species, Clostridium arbusti sp. nov.