Alkalibacterium thalassium sp. nov., Alkalibacterium pelagium sp. nov., Alkalibacterium putridalgicola sp. nov. and Alkalibacterium kapii sp. nov., slightly halophilic and alkaliphilic marine lactic acid bacteria isolated from marine organisms and salted foods collected in Japan and Thailand

1 Department of Fermentation Science, Faculty of Applied Bio-Science, Tokyo University of Agriculture, 1-1 Sakuragaoka 1-chome, Setagaya-ku, Tokyo 156-8502, Japan 2 Department of Microbiology, Faculty of Pharmaceutical Sciences, Chulalongkorn University, 254 Phayathai Road, Wangmai, Pathumwan, Bangkok 10330, Thailand Correspondence Morio Ishikawa m1ishika{at}nodai.ac.jp We describe 10 new strains of marine lactic acid bacteria isolated from decaying marine algae, decaying seagrass, raw fish, salted fish and salted and fermented shrimp paste (‘ka-pi’) collected from a temperate area of Japan and Thailand. The isolates are Gram-positive and non-sporulating. They have motility with peritrichous flagella depending on the strains. They lack catalase and quinones. Under anaerobic conditions, lactate yields were 64–93 % of the glucose consumed; residual products were formate, acetate and ethanol with a molar ratio of approximately 2 : 1 : 1. The pH of the fermentation medium markedly affected the product composition; at higher pH, the yield of lactate decreased (15–48 % at pH 9.0) and yields of other products increased, retaining the molar ratio. Under aerobic conditions, acetate and lactate were produced from carbohydrates and related compounds. The isolates were slightly halophilic, highly halotolerant and alkaliphilic. The optimum NaCl concentration for growth ranged between 0.5 and 4.0 % (w/v), depending on the strain, with a growth range of between 0 and 17–21 % (11 % for one isolate). The optimum pH for growth ranged between 8.0 and 9.5, with a growth range of 6.0–11.0, depending on the strains. Comparative sequence analysis of the 16S rRNA genes revealed that the isolates occupied three phylogenetic positions within the genus Alkalibacterium , showing 97.1–99.8 % similarity to Alkalibacterium indicireducens . DNA–DNA hybridization values (