α-amylase and β-galactosidase production on Potato starch waste by Lactococcus lactis subsp lactis isolated from pickled yam

Potato starch waste, a chips industry effluent, was used for the production of industrially important enzymes by an amylolytic strain of lactic acid bacteria, isolated from pickled yam & identified as Lactococcus lactis. The strain was observed to co-produce α-amylase and β-galactosidase. Potato starch waste was efficiently utilized (91.6%) along with high co-production of α-amylase and β-galactosidase. Optimum culture conditions favouring maximum production of these two hydrolases in MRS medium containing 2% potato starch were temperature 55°C, pH 7 and temperature 35°C, pH 5 for α-amylase (2.54 U/mL) and β-galactosidase (2.67 U/mL) respectively. In potato starch waste, Lactococcus lactis retained viability and could co-produce α-amylase (17.54 U/mL) and β-galactosidase (25.35 U/mL) at a temperature of 45oC and pH 6.5 within a period of 48 hrs. Thus, the study suggests a potential applicability of the isolate for the production of industrially significant hydrolases from a cheap agro industrial source.