Lysinibacillus chungkukjangi sp. nov., isolated from Chungkukjang, Korean fermented soybean food

One bacterial strain 2RL3-2T was isolated from Chungkukjang, a traditional Korean fermented food made from soybeans, and determined to be a Gram-positive, aerobic, spore-forming rod. Growth of the novel strain was optimal at 30°C and pH 7.0. The 16S rRNA gene of strain 2RL3-2T showed the highest level of sequence similarity to Lysinibacillus sinduriensis BLB-1T (99.0%), Lysinibacillus massiliensis 4400831T (97.1%), Lysinibacillus xylanilyticus XDB9T (97.0%), and Lysinibacillus odysseyi 34hs-1T (96.8%). Phylogenetic analysis showed that strain 2RL3-2T formed a robust cluster with L. sinduriensis BLB-1T, L. massiliensis 4400831T, and L. odyssey 34hs-1T. The major fatty acids were anteiso-C15:0 (47.3%), iso-C16:0 (16.3%), and anteiso-C17:0 (11.3%), and the only menaquinone was MK-7. Diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine were the major polar lipids, along with an unknown phospholipid and two unknown lipids. The peptidoglycan type was A4α, with an interpeptide bridge of l-Lys-d-Asp. DNA-DNA hybridization values between strain 2RL3-2T and closely related Lysinibacillus species were below 43±4%. Therefore, based on phenotypic, chemotaxonomic, and phylogenetic characteristics, it was determined that strain 2RL3-2T represents a novel species of the genus Lysinibacillus, for which the name Lysinibacillus chungkukjangi sp. nov. is proposed. The type strain is 2RL3-2T (=KACC 16626T =NBRC 108948T).