Optimization of β-galactosidase Production from Yogurt and Dairy Soil Associated Bacteria Using Different Fermentation Media

Aims: The aim of current research was the production of β-galactosidase enzyme from Lactobacillus delbruekii subsp. bulgaricus isolated form yogurt and soil samples.

Study Design: Production of β-galactosidase.

Place and Duration of Study: Microbiology laboratory, Department of Zoology, GC University, Lahore, Pakistan, between 14 Nov, 2013 and 29 Nov, 2014.

Methodology: Bacterial isolates were isolated from yogurt and soil samples. Morphological, biochemical characterization, and 16S rRNA sequencing was used for the identification of the bacterial strains. The optimization and maximum production of β-galactosidase was carried out by using various temperatures, pH, carbon sources (corn flour, wheat flour, rice flour), nitrogen sources (Trypton, Peptone, Yeast extract), and incubation periods.

Results: National Centre for Biotechnology Information (NCBI) Blast analyzed that A11, A13 and A14 strains belongs to Lactobacillus delbruekii subsp. bulgaricus with accession numbers KP256199, KP264120, and KP264121. Maximum enzyme production was obtained after 48 h of incubation at 40-45°C temperature at pH 6.0-7.0. The highest enzyme production was observed in the presence of rice flour and yeast extract. The maximum enzyme activity was shown by A11, A13 and A25 (7.69 U/mL, 7.25 U/mL, and 7.28 U/mL).

Conclusion: Rice flour could be the potential carbon source for the production of β-galactosidase from Lactobacillus delbruekii subsp. bulgaricus whereas nitrogen sources reduced its production. Temperature and pH was important physical parameter for the production of β-galactosidase from yogurt and soil associated bacteria.