Lysinibacillus piscis sp. nov. isolated from the gut of mottled spinefoot Siganus fuscescens.

A novel Lysinibacillus strain, designated KH24, was isolated from the gut of Siganus fuscescens, a herbivorous fish, which was captured off the coast of Okinawa, Japan. Strain KH24 is a rod-shaped, Gram-stain-positive, spore-forming, and motile bacterium that forms off-white colonies. The 16S rRNA gene sequence of strain KH24 showed the highest similarity (97.4%) with Lysinibacillus pakistanensis JCM 18776 and L. irui IRB4-01. Genomic similarities between strain KH24 and Lysinibacillus type strains, based on average nucleotide identity, digital DNA-DNA hybridization (genome-to-genome distance calculation), and average amino acid identity were 70.4-77.7%, 17.1-24.4%, and 69.2-81.2%, respectively, which were lower than species delineation thresholds. Strain KH24 growth occurred at pH values of 5.5-8.5, temperatures of 20-40 °C, and NaCl concentrations of 0-4.0%, and optimally at pH 7.0, 30 °C, and 0%, respectively. Unlike related Lysinibacillus type strains, strain KH24 could assimilate D-glucose, D-fructose, N-acetyl-glucosamine, amygdalin, arbutin, esculin, ferric citrate, salicin, D-cellobiose, D-maltose, D-sucrose, and gentiobiose. Major fatty acids included iso-C (45.8%), anteiso-C (15.1%), iso-C (12.6%), and anteiso-C (10.9%). Menaquinone-7 was the predominant quinone, and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, and lysophosphatidylethanolamine. Based on its genetic and phenotypic properties, strain KH24 represents a novel species of the genus Lysinibacillus, for which the name Lysinibacillus piscis sp. nov. is proposed. The type strain is KH24 (= JCM 36611 = KCTC 43676).