Lactic acid bacteria (LAB) are the predominant micro-organisms in tempoyak, a Malaysian acid-fermented condiment. In a study on the diversity of LAB in this product, three isolates could not be identified using SDS-PAGE of whole-cell proteins or API 50 CH. The taxonomic position of the three isolates was clarified in the present study. 16S rDNA sequencing classified a representative strain in the genus Lactobacillus, clearly separated from all known species, and most closely related to the Lactobacillus reuteri phylogenetic group. DNA-DNA hybridization experiments and an extensive phenotypic description confirm that the strains represent a single and separate novel species among the obligately heterofermentative lactobacilli. The three isolates are distinguished at the intra-species level by plasmid profiling, pulsed-field gel electrophoresis of macro-restriction fragments and biochemical features. The name Lactobacillus durianis sp. nov. is proposed for the novel taxon and the type strain is LMG 19193T (= CCUG 45405T).
A taxonomic study was conducted to clarify the relationships of two bacterial populations belonging to the genus Weissella. A total of 39 strains originating mainly from Malaysian foods (22 strains) and clinical samples from humans (9 strains) and animals (6 strains) were analysed using a polyphasic taxonomic approach. The methods included classical phenotyping, whole-cell protein electrophoresis, 16S and 23S rDNA RFLP (ribotyping), determination of 16S rDNA sequence homologies and DNA-DNA reassociation levels. Based on the results, the strains were considered to represent two different species, Weissella confusa and a novel Weissella species, for which the name Weissella cibaria sp. nov. is proposed. Weisella confusa possessed the highest 16S rDNA sequence similarity to Weisella cibaria, but the DNA-DNA reassociation experiment showed hybridization levels below 49% between the strains studied. The numerical analyses of Weisella confusa and Weisella cibaria strains did not reveal any specific clustering with respect to the origin of the strains. Based on whole-cell protein electrophoresis, and ClaI and HindIII ribotyping patterns, food and clinical isolates were randomly located in the two species-specific clusters obtained.
Three lactic acid bacterial (LAB) strains obtained from a Malaysian acid-fermented condiment, tempoyak (made from pulp of the durian fruit), showed analogous but distinct patterns after screening by SDS-PAGE of whole-cell proteins and comparison with profiles of all recognized LAB species. 16S rRNA gene sequencing of one representative strain showed that the taxon belongs phylogenetically to the genus Leuconostoc, with its nearest neighbour being Leuconostoc fructosum (98 % sequence similarity). Biochemical characteristics and DNA-DNA hybridization experiments demonstrated that the strains differ from Leuconostoc fructosum and represent a single, novel Leuconostoc species for which the name Leuconostoc durionis sp. nov. is proposed. The type strain is LMG 22556(T) (= LAB 1679(T) = D-24(T) = CCUG 49949(T)).