Phenotypic and Genotypic Characterization of Lactic Acid Bacteria Isolated from Some Nigerian Traditional Fermented Foods

Abstract

A total of 104 lactic acid bacteria were isolated from ogi, wara, fermenting cassava mash for local food product gari and raw milk for nono. They were characterized phenotypically and divided into six main groups, which are facultative heterofermentative rods, obligate heterofermentative rods, tetrad-forming homofermentative cocci, homofermentative cocci, heterofermentative cocci, and an unidentified group. A total of 40 strains with good acidification, hydrogen peroxide production, and fermentation of indigestible sugar such as raffinose were selected. They were further characterized employing genotypic fingerprinting techniques, such as RAPD-PCR with primer M13, rep-PCR with primer (GTG)5 and sequencing of the 16S rDNA genes for starter culture development. RAPD-PCR did not give accurate delineation of the strains, but with the combination of rep-PCR fingerprinting and 16S rDNA sequencing, representative strains from rep-PCR clusters at 80% Pearson's correlation coefficient (r) grouped the organisms to nine (9) clusters. These were identified as Lactobacillus fermentum (7), Lactobacillus plantarum (6), Lactobacillus pentosus (2), Pediococcus pentosaceus (10), Pediococcus acidilactici (4), Enterococcus faecium (7), and the unidentified Lactobacillus species (4) were assigned into Lactobacillus fermentum group. A polyphasic taxonomic approach for characterization proved useful in the accurate typing of the LAB strains.