Formulation of low-cost, lactose-free production medium by response surface methodology for the production of β-galactosidase using halotolerant Aspergillus tubengensis GR-1

In the present investigation, a halotolerant Aspergillus tubengensis GR1was isolated from man-made solar saltern region located at Khambhat, Gujarat and identified using 28S rDNA partial genome sequencing. The effect of carbon source, nitrogen source and other growth conditions on β-galactosidase production was investigated. Lactose-free, low cost medium was optimized using response surface methodology. Wheat bran, corn steep liquor and NaCl were assessed for the production of β-galactosidase. Wheat bran 0.5 g% (w/v), corn steep liquor 1 g% (w/v) and NaCl 5 g% (w/v) was found to be optimum for the maximized production of β-galactosidase. The enzyme production (352±2) U/mL was maximum after 96 h of incubation in an optimized low-cost, lactose-free medium with 4.69 fold increase in the production of β-galactosidase. These results suggest the feasibility for the large scale production of β-galactosidase from A. tubengensis GR1 on an industrial scale.