Isolation, biochemical and molecular characterization of lactic acid bacteria from whey of a Nigerian traditionally fermented yoghurt drink

Abstract

Lactic Acid Bacteria (LAB) have been identified as an essentialgroup of microorganisms due to the health-promoting effects theyexert on human and animal hosts. This research was conducted to,isolate LAB from whey obtained from kindirmo a locally fermentedcow milk product in Nigeria, characterize the strains based onphysiological and biochemical properties and identify them using16SrRNA sequencing. A total of 32 samples were collectedaseptically and the whey cultured on an MRS and M17 media.Physiological and biochemical results showed that the isolatedorganisms, which were mostly rod and cocci shaped, includedgram positive and catalase negative species. The organisms didnot only vary in their abilities to tolerate and grow at differentconcentrations of pH, temperature and NaCl, but were able toferment twelve different sugars distinctively. The ten most desirablestrains obtained were subsequently screened by moleculartechniques using PCR and sequence analysis. The PCR resultsrevealed that 98% of the identified organisms were Lactobacillusbulgaricus, Lactobacillus casei, Lactobacillus acidophilus,Streptococcus thermophilus, Lactobacillus gasseri andLactobacillus plantarum. These findings showed that kindirmocould be an excellent and potential source of probiotic bacteria,which are often the main sources of probiotics. Further screeningand identification processes were recommended to ascertain thefunctional, technological and probiotic properties of the strains.