Fictibacillus phosphorivorans gen. nov., sp. nov. and proposal to reclassify Bacillus arsenicus, Bacillus barbaricus, Bacillus macauensis, Bacillus nanhaiensis, Bacillus rigui, Bacillus solisalsi and Bacillus gelatini in the genus Fictibacillus

Abstract

A Gram-positive-staining, aerobic, endospore-forming bacterium (Ca7(T)) was isolated from a bioreactor showing extensive phosphorus removal. Based on 16S rRNA gene sequence similarity comparisons, strain Ca7(T) was grouped in the genus Bacillus, most closely related to Bacillus nanhaiensis JSM 082006(T) (100 %), Bacillus barbaricus V2-BIII-A2(T) (99.2 %) and Bacillus arsenicus Con a/3(T) (97.7 %). Moderate 16S rRNA gene sequence similarities were found to the type strains of the species Bacillus gelatini and Bacillus rigui (96.4 %), Bacillus macauensis (95.1 %) and Bacillus solisalsi (96.1 %). All these species were grouped into a monophyletic cluster and showed very low sequence similarities (<94 %) to the type species of the genus Bacillus, Bacillus subtilis. The quinone system of strain Ca7(T) consists predominantly of menaquinone MK-7. The polar lipid profile exhibited the major compounds diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. In addition, minor compounds of an unidentified phospholipid and an aminophospholipid were detected. No glycolipids were found in strain Ca7(T), which was consistent with the lipid profiles of B. nanhaiensis, B. barbaricus, B. arsenicus, B. rigui, B. solisalsi, B. macauensis and B. gelatini, but in contrast to B. subtilis. The diagnostic diamino acid of the peptidoglycan was meso-diaminopimelic acid and the polyamine pattern contained predominantly spermidine and spermine. The major fatty acids, which were iso-C15 : 0, anteiso-C15 : 0 and C16 : 0, supported the grouping of strain Ca7(T) in the family Bacillaceae. The strain showed DNA-DNA similarities of 48 % (reciprocal 47 %) to B. nanhaiensis DSM 23009(T), 31 % (reciprocal 36 %) to B. barbaricus V2-BIII-A2(T) and 29 % (reciprocal 39 %) to B. arsenicus DSM 15822(T), respectively. These results clearly demonstrate that strain Ca7(T) is a representative of a novel species, which can be differentiated from its closest relatives by physiological and biochemical tests. Because of the low sequence similarity of strain Ca7(T) to B. subtilis, which was shared by B. nanhaiensis, B. barbaricus, B. arsenicus, B. gelatini, B. rigui, B. solisalsi and B. macauensis, and their unique lipid patterns, we propose that strain Ca7(T) represents a novel species in a novel genus for which the name Fictibacillus phosphorivorans gen. nov., sp. nov. is proposed. The type strain is Ca7(T) (= CCM 8426(T) = LMG 27063(T)). In addition we propose the reclassification of B. nanhaiensis, B. barbaricus, B. arsenicus, B. rigui, B. macauensis, B. solisalsi and B. gelatini as Fictibacillus nanhaiensis comb. nov., Fictibacillus barbaricus comb. nov., Fictibacillus arsenicus comb. nov., Fictibacillus rigui comb. nov., Fictibacillus macauensis comb. nov., Fictibacillus solisalsi comb. nov. and Fictibacillus gelatini comb. nov., respectively [type strains JSM 082006(T) (= DSM 23009(T) = KCTC 13712(T)), V2-BIII-A2(T) ( = CCM 4982(T) = DSM 14730(T)), Con a/3(T) ( = MTCC 4380(T) = DSM 15822(T) = JCM 12167(T)), WPCB074(T) ( = KCTC 13278(T) = JCM 16348(T)), ZFHKF-1(T) ( = JCM 13285(T) = DSM 17262(T)), YC1(T) ( = KCTC 13181(T) = CGMCC 1.6854(T)) and LMG 21881(T) ( = DSM 15866(T)), respectively].