Description of antibiotic-producing novel bacteria sp. nov. and sp. nov.

Two white colony-forming, Gram-stain-negative, non-sporulating and motile bacteria, designated G-4-1-8 and RP-4-7, were isolated from forest soil and Arctic soil, respectively. Both strains showed antimicrobial activity against Gram-negative pathogens ( and ) and could grow at a pH range of pH 4.0-11.0 (optimum, pH 7.0-9.0). Phylogenetic analyses based on their 16S rRNA gene sequences indicated that strains G-4-1-8 and RP-4-7 formed a lineage within the family and were clustered as members of the genus . Strain G-4-1-8 showed the highest 16S rRNA sequence similarity to JC2948 (98.1 %), while strain RP-4-7 showed the highest similarity to DNBP6-1 (98.8 %). The only respiratory quinone in both strains was ubiquinone Q-8. Their principal cellular fatty acids were C, cyclo-C, summed feature 3 (iso-C 2-OH and/or C 7) and summed feature 8 (C 7 and/or C 6). Their major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and an unidentified aminophospholipid. The DNA G+C content of strains G-4-1-8 and RP-4-7 were 63.7 and 61.3 mol%, respectively, while their genome lengths were 7.44 and 9.67 Mb, respectively. The genomes of both strains showed at least 12 putative biosynthetic gene clusters. The average nucleotide identity and DNA-DNA hybridization relatedness values between both strains and most closely related species were below the species threshold values. Based on a polyphasic study, these isolated strains represent novel species belonging to the genus , for which the names sp. nov. (G-4-1-8= KACC 21617=NBRC 114603) and sp. nov. (RP-4-7=KACC 21621=NBRC 114605) are proposed.