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 essential
group of microorganisms due to the health-promoting effects they
exert on human and animal hosts. This research was conducted to,
isolate LAB from whey obtained from kindirmo a locally fermented
cow milk product in Nigeria, characterize the strains based on
physiological and biochemical properties and identify them using
16SrRNA sequencing. A total of 32 samples were collected
aseptically and the whey cultured on an MRS and M17 media.
Physiological and biochemical results showed that the isolated
organisms, which were mostly rod and cocci shaped, included
gram positive and catalase negative species. The organisms did
not only vary in their abilities to tolerate and grow at different
concentrations of pH, temperature and NaCl, but were able to
ferment twelve different sugars distinctively. The ten most desirable
strains obtained were subsequently screened by molecular
techniques using PCR and sequence analysis. The PCR results
revealed that 98% of the identified organisms were Lactobacillus
bulgaricus, Lactobacillus casei, Lactobacillus acidophilus,
Streptococcus thermophilus, Lactobacillus gasseri and
Lactobacillus plantarum. These findings showed that kindirmo
could be an excellent and potential source of probiotic bacteria,
which are often the main sources of probiotics. Further screening
and identification processes were recommended to ascertain the
functional, technological and probiotic properties of the strains.