Anaerovirgula multivorans gen. nov., sp. nov., a novel spore-forming, alkaliphilic anaerobe isolated from Owens Lake, California, USA

A novel, alkaliphilic, obligately anaerobic bacterium, strain SCA(T), was isolated from mud sediments of a soda lake in California, USA. The rod-shaped cells were motile, Gram-positive, formed spores and were 0.4-0.5x2.5-5.0 μm in size. Growth occurred within the pH range 6.7-10.0 and was optimal at pH 8.5. The temperature range for growth was 10-45 °C, with optimal growth at 35 °C. NaCl was required for growth. Growth occurred at 0.5-9.0 % (w/v) NaCl and was optimal at 1-2 % (w/v). The novel isolate was a catalase-negative chemo-organoheterotroph that fermented sugars, proteolysis products, some organic and amino acids, glycerol, D-cellobiose and cellulose. It was also capable of growth by the Stickland reaction. Strain SCA(T) was sensitive to tetracycline, chloramphenicol, rifampicin and gentamicin, but it was resistant to ampicillin and kanamycin. The G+C content of the genomic DNA was 34.2 mol%. Major fatty acid components were C(14 : 0), iso-C(15 : 0), C(16 : 1)omega9c and C(16 : 0). 16S rRNA gene sequence analysis of strain SCA(T) showed a similarity of approximately 97 % with the type strains of Clostridium formicaceticum and Clostridium aceticum in clostridial cluster XI and a similarity of less than 94.2 % to any other recognized Clostridium species and those of related genera in this cluster. Strain SCA(T) was clearly differentiated from C. formicaceticum and C. aceticum based on comparison of their phenotypic properties and fatty acid profiles, as well as low levels of DNA-DNA relatedness between strain SCA(T) and the type strains of these two species. Therefore, strain SCA(T) is considered to represent a novel species of a new genus, Anaerovirgula multivorans gen. nov., sp. nov., in clostridial cluster XI. The type strain is SCA(T) (=ATCC BAA-1084(T)=JCM 12857(T)=DSM 17722(T)=CIP 107910(T)).