Identification of lactic acid bacteria from fermented tea leaves (miang) in Thailand and proposals of Lactobacillus thailandensis sp. nov., Lactobacillus camelliae sp. nov., and Pediococcus siamensis sp. nov.

Abstract

Eighteen rod-shaped homofermentatives, six heterofermentatives, and a coccal homofermentative lactic acid bacteria were isolated from fermented tea leaves (miang) produced in the northern part of Thailand. The isolates were placed in a monophyletic cluster consisting of Lactobacillus and Pediococcus species. They were divided into seven groups by phenotypic and chemotaxonomic characteristics, DNA-DNA similarity, and 16S rRNA gene sequences. Groups I to VI belonged to Lactobacillus and Group VII to Pediococcus. All of the strains tested produced DL-lactic acid but those in Group IV produced L-lactic acid. The strains tested in Groups I, II and V had meso-diaminopimelic acid in the cell wall. Six strains in Group I were identified as Lactobacillus pantheris; five strains in Group II as Lactobacillus pentosus; and four strains in Group V as Lactobacillus suebicus. Two strains in Group VI showed high DNA-DNA similarity for each other and MCH4-2 was closest to Lactobacillus fermentum CECT 562T with 99.5% of 16S rRNA gene sequence similarity. Five strains in Group III are proposed as Lactobacillus thailandensis sp. nov., and MCH5-2T (BCC 21235T=JCM 13996T=NRIC 0671T=PCU 272T) is the type strain which has 49 mol% G+C of DNA. Two strains in Group IV are proposed as Lactobacillus camelliae sp. nov., and the type strain is MCH3-1T (BCC 21233T=JCM 13995T=NRIC 0672T=PCU 273T) which has 51.9 mol% G+C of DNA. One strain in Group VII is proposed as Pediococcus siamensis sp. nov., and MCH3-2T (BCC 21234T=JCM 13997T=NRIC 0675T=PCU 274T) is the type strain which has 42 mol% G+C of DNA.