Paenibacillus silvisoli sp. nov. and Paenibacillus humicola sp. nov., isolated from forest soil.

During the study of microbial ecology of forest soil, two circular, white-colored bacterial colonies were isolated and labeled as strains TW38 and TW40. Both strains were catalase positive and oxidase negative. Strains TW38 and TW40 demonstrated growth within a temperature range of 10-37 °C and 18-37 °C, respectively, and thrived within a pH range of 5.5-9.0 and 6.0-8.0, respectively. Both strains grew at 0-2.0% (w/v) NaCl concentrations. The phylogenetic analysis indicated that strains TW38 and TW40 affiliated to the genus Paenibacillus, with the closest neighbors being Paenibacillus montanisoli RA17 (98.6%) and Paenibacillus arachidis E3 (95.4%), respectively. In both strains, the sole respiratory quinone was MK-7, the signature fatty acid was antiso-C, and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and phosphatidylcholine. The digital DNA-DNA hybridization and the average nucleotide identity values between TW38, TW40, and closest reference strains were < 29.0% and < 85.0%, respectively. The DNA G+C content of TW38 and TW40 was 54.5% and 57.1%, respectively. In general, the phylogenetic, genomics, chemotaxonomic, and phenotypic data support the differentiation of TW38 and TW40 from other closest members of the genus Paenibacillus. Thus, we conclude both strains TW38 and TW40 represent novel species of the genus Paenibacillus, for which the name Paenibacillus silvisoli sp. nov. and Paenibacillus humicola sp. nov. are proposed, respectively. The type strain of Paenibacillus silvisoli is TW38 (= KCTC 43468 = NBRC 116015) and type strain of Paenibacillus humicola is TW40 (= KCTC 43469 = NBRC 116016).