Paenibacillus siamensis sp. nov., Paenibacillus septentrionalis sp. nov. and Paenibacillus montaniterrae sp. nov., xylanase-producing bacteria from Thai soils.

Three strains of xylanase-producing bacteria, S5-3(T), X13-1(T) and MXC2-2(T), isolated from soils in Thailand, were characterized taxonomically based on their phenotypic and chemotaxonomic characteristics and 16S rRNA gene sequence comparisons. They were Gram-positive, facultatively anaerobic, spore-forming, rod-shaped bacteria. They contained meso-diaminopimelic acid in the cell-wall peptidoglycan. The DNA G+C contents were respectively 45.8, 47.3 and 48.8 mol%. The predominant isoprenoid quinone was MK-7, and anteiso-C(15 : 0) and C(16 : 0) were the dominant cellular fatty acids. Phylogenetic analyses based on 16S rRNA gene sequence comparison showed that they were affiliated to the genus Paenibacillus. Strains S5-3(T), X13-1(T) and MXC2-2(T) were closely related to Paenibacillus granivorans A30(T) and Paenibacillus agaridevorans DSM 1355(T) (94.7-98.6 % 16S rRNA gene sequence similarity). The similarity between the three novel strains ranged from 96.3 to 98.4 %. DNA-DNA relatedness, DNA G+C contents and some phenotypic characteristics could clearly distinguish the strains from each other and from related Paenibacillus species. Therefore, strains S5-3(T), X13-1(T) and MXC2-2(T) represent novel species of the genus Paenibacillus, for which the names Paenibacillus siamensis sp. nov. (type strain S5-3(T) =KCTC 13038(T) =PCU 279(T) =TISTR 1831(T)), Paenibacillus septentrionalis sp. nov. (type strain X13-1(T) =KCTC 13039(T) =PCU 280(T) =TISTR 1830(T)) and Paenibacillus montaniterrae sp. nov. (type strain MXC2-2(T) =KCTC 13036(T) =PCU 281(T) =TISTR 1836(T)) are proposed.