Allobacillus salarius sp. nov., and Allobacillus saliphilus sp. nov., isolated from shrimp paste (ka-pi) in Thailand

Abstract

Two strains of moderately halophilic, Gram-stain-positive and spore-forming rods, designated as SKP4-8^T and SKP8-2^T isolated from shrimp paste (Ka-pi), were taxonomic studied based on polyphasic approach. Strain SKP4-8^T grew at pH 6.0-9.0 (optimum 7.0), at 25-45 °C (optimum 37 °C) and in 1-16% (w/v) NaCl (optimum 5-10%). Strain SKP8-2^T grew at pH 6.0-9.0 (optimum 8.0), at 25-45 °C (optimum 37 °C) and in 0-20% (w/v) NaCl (optimum 3-10%). The strains contained meso-diaminopimelic acid in cell-wall peptidoglycan and the major menaquinone was MK-7. Strain SKP4-8^T contained iso-C_15:0, anteiso-C_15:0 and iso-C_17:0; and strain SKP8-2^T contained anteiso-C_15:0, iso-C_15:0, iso-C_16:0 and antesio-C_17:0 as major cellular fatty acids. Phosphatidylglycerol, diphosphatidylglycerol, unknown phospholipids and an unknown glycolipid were detected as major polar lipids. On the basis of 16S rRNA gene sequence analysis, strains SKP4-8^T and SKP8-2^T belonged to the genus Allobacillus and were closely related to Allobacillus halotolerans LMG 24826^T with 98.8% and 99.3% similarity, respectively. The comparative genome analysis based on average nucleotide identity (ANI) and digital DNA-DNA hybridization revealed that both strains showed the values below 95 and 70%, from each other and from Allobacillus halotolerans LMG 24826^T, respectively. Based on the data from this polyphasic study, strains SKP4-8^T and SKP8-2^T represent novel species of the genus Allobacillus and the name Allobacillus salarius sp. nov. was proposed for SKP4-8^T (= KCTC 33905^T = LMG 30016^T = TISTR 2499^T); and Allobacillus saliphilus sp. nov. for SKP8-2^T (= KCTC 33906^T = LMG 29682^T = TISTR 2558^T).

Keywords: Allobacillus salarius; Allobacillus saliphilus; Moderately halophile; Shrimp paste; Spore-forming bacteria.