Transgalactosylating β-galactosidase from probiotic Lactobacillus plantarum MCC2156: production and permeabilization for use as whole cell biocatalyst

Key nutritional factors were optimized for the maximum
production of transgalactosylating β-galactosidase
from Lactobacillus plantarum MCC2156. Galactose, yeast
extract, sodium acetate and manganese sulphate were the most
important nutrients affecting β-galactosidase production.
Maximum β-galactosidase production (3015 miller units)
was obtained by culturing L. plantarum in the optimized
fermentation medium containing (w/v) galactose (4 %), yeast
extract (2 %), sodium acetate (3 %) and manganese sulphate
(0.075 %) with an optimum medium pH of 7.0, after 14 h of
incubation at 35 °C. Further, permeabilization of L. plantarum
cells using various chemical/ solvents for maximum β-
galactosidase activity was performed for use as whole cell
biocatalyst. Mixture of ethanol: n-butanol was found to effectively
permeabilize the cells with maximum β-galactosidase
activity under the following optimum conditions; 1: 1 mixture
of ethanol (10 %, v/v): n-butanol (30 %, v/v) with a contact
time of 10 min at 28±2 °C.