A new subspecies of Anoxybacillus flavithermus ssp yunnanensis ssp nov with very high ethanol tolerance

In a search for thermophilic ethanol-tolerant bacteria, water-sediment samples collected at springs in Yunnan province of China were screened by ethanol enrichment. A novel thermophilic bacterium, strain E13T, was isolated. It exhibits a unique and remarkable ability to preferably grow in the presence of ethanol and is able to tolerate 13% (v/v) ethanol at 60 degrees C. The isolate is a facultative aerobic, Gram-positive, motile, spore-forming rod that is capable of utilizing a range of carbon sources, such as xylose, arabinose and cellobiose. Phylogenetic analysis based on 16S rRNA gene similarity showed the strain to be affiliated with the species Anoxybacillus flavithermus (99.2% sequence similarity). DNA-DNA hybridization comparisons demonstrated a 64.8% DNA-DNA relatedness between strain E13T and A. flavithermus DSM 2641T. On the basis of phenotypic characteristics, phylogenetic data and DNA-DNA hybridization data, it was concluded that the isolate merited classification as a novel subspecies of A. flavithermus, for which the name Anoxybacillus flavithermus ssp. yunnanensis ssp. nov. is proposed. The type strain of this subspecies is E13T (=CCTCC AB2010187T=KCTC 13759T).