Amphibacillus xylanus gen. nov., sp. nov., a Facultatively Anaerobic Sporeforming Xylan-Digesting Bacterium Which Lacks Cytochrome, Quinone, and Catalase

Three strains of gram-positive, facultatively anaerobic, sporeforming, rod-shaped bacteria were isolated from composts of manure with grass and rice straw. These organisms grew well in an alkaline medium and digested xylan both in strictly anaerobic cultures when titanium(III) citrate was used as a reducing agent and in aerobic cultures with shaking. The cells contained meso-diaminopimelic acid, and their cellular fatty acids consisted of iso- and anteiso-branched acids and considerable amounts of straight-chain acids. The DNA base composition of these strains ranged from 36 to 38 mol% guanine plus cytosine. Cytochromes, isoprenoid quinones, and catalase activity were not detected. DNA-DNA homology determinations did not show relatedness to strains of representative species of the genera Bacillus, Clostridium, and Sporolactobacillus. Considering the uniqueness of the characteristics, the sequence of the 5S rRNA, and the unique metabolic pathways, we propose Amphibacillus xylanus gen. nov., sp. nov., for these strains. The type strain is strain Ep01 (= JCM 7361).