Alkalibacterium psychrotolerans sp. nov., a psychrotolerant obligate alkaliphile that reduces an indigo dye.

A psychrotolerant, obligately alkaliphilic bacterium, IDR2-2(T), 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 9-12 but not at pH 7-8. It was a Gram-positive, facultatively anaerobic, straight rod-shaped bacterium with peritrichous flagella. The isolate grew in 0-17 % (w/v) NaCl but not at NaCl concentrations higher than 18 % (w/v). Its major cellular fatty acids were C(14 : 0), C(16 : 0), C(16 : 1)9c and C(18 : 1)9c, 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 A4beta, Orn-d-Glu. A phylogenetic analysis based on 16S rRNA gene sequence data indicated that strain IDR2-2(T) is a member of the genus Alkalibacterium. DNA-DNA 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 DNA-DNA relatedness data, the isolate merits classification as a novel species, for which the name Alkalibacterium psychrotolerans sp. nov. is proposed. The type strain is IDR2-2(T) (=JCM 12281(T)=NCIMB 13981(T)).