干旱区生态环境知识资源中心

An obligate anaerobic, mesophilic, motile and enclospore-forming bacterium, designated 1D was isolated from a subsurface soil sample. The young culture of strain 1D(T) was Gram-positive and formed oval spores that were central in position. Based on the biochemical, chemotaxonomic and physiological data, strain 1D(T) appears to be a member of the genus Clostridium. Strain 1D(T) was found to be capable of degrading p-nitrophenol (pNP) at a concentration of 0.5 mM under anaerobic conditions as revealed by HIPLC analysis. The major fatty acids were C-16:0 (28.02%), iso-C-17:1 I/anteiso B (23.05%) and C-14:0 (10.02%). The major polar lipid content was cliphosphatidylglycerol. Strain 1D(T) showed highest 16S rRNA gene sequence similarity to Clostridium aciditolerans JW/YJL-B3(T) (98.2 %) and similarity was less for Clostridium scatologenes ATCC 25775(T) (95.1 0/b), Clostridium drakei SL1(T) (95.0%) and Clostridium carboxidivorans P7(T) (95.0%). Phylogenetic analysis showed that it formed a coherent cluster with the species belonging to cluster I of the genus Clostridium. The DNA G+C content was 35.5 mol%. DNA-DNA hybridization analysis indicated a mean value of 36.4% between strain 1D(T) and its closest relative C. aciditolerans. Several phenotypic differences from the closely related species were also revealed. On the basis of the polyphasic characteristics, strain 1D(T) represents a novel species of the genus Clostridium, for which the name Clostridium nitrophenolicum sp. nov. is proposed. The type strain is 1D(T) (=MTCC 7832(T)=JCM 14030(T)).