Abstract
A psychrotolerant, obligately alkaliphilic bacterium, IDR2-2T, which is able to reduce indigo dye was isolated from a fermented polygonum indigo (Polygonum tinctorium Lour.) produced in Date, Hokkaido, using a traditional Japanese method. The isolate grew at pH 912 but not at pH 78. It was a Gram-positive, facultatively anaerobic, straight rod-shaped bacterium with peritrichous flagella. The isolate grew in 017 % (w/v) NaCl but not at NaCl concentrations higher than 18 % (w/v). Its major cellular fatty acids were C14 : 0, C16 : 0, C16 : 19c and C18 : 19c, and its DNA G+C content was 40·6 mol%. DL-lactic acid was the major end-product from D-glucose. No quinones could be detected. The peptidoglycan type was A4β, OrnD-Glu. A phylogenetic analysis based on 16S rRNA gene sequence data indicated that strain IDR2-2T is a member of the genus Alkalibacterium. DNADNA hybridization revealed low relatedness (less than 25 %) between the isolate and two phylogenetically related strains, Alkalibacterium olivapovliticus and Marinilactibacillus psychrotolerans. On the basis of phenotypic characteristics, phylogenetic data and DNADNA relatedness data, the isolate merits classification as a novel species, for which the name Alkalibacterium psychrotolerans sp. nov. is proposed. The type strain is IDR2-2T (=JCM 12281T=NCIMB 13981T).