Utilização de resíduos agroindustriais em processo biotecnológico para produção de B-galactosidase de Kluyveromyces marxianus CCT 7082

Use of agroindustrial residues in biotechnological process by beta- galactosidase production from Kluyveromyces marxianus CCT 7082. The objective of this work was to evaluate the composition of the culture medium for the production of the enzyme -galactosidase from Kluyveromyces marxianus CCT 7082 using an experimental design. Enzyme production was carried out in a medium consisting of cheese whey, corn steep liquor (CSL) and Prodex-lac ® yeast hydrolyzate. A factorial fractional design (2 5-1 ) was performed to determine the significant variables in the production of the enzyme. Different concentrations of lactose present in whey (10-70 g L -1 ), CSL (10-100 g L -1 ), Prodex-lac (40- 20 g L -1 ), (NH4)2SO4 (0-10 g L -1 ) and pH (5-7) were tested. Lactose concentration, CSL and pH were the variables that showed a statistically significant effect on enzyme activity within the ranges studied, and these variables were used in a central composite rotatable design to optimize production of the enzyme. The ranges used were: lactose concentration 40-100 g L -1 , CSL 10-120 g L -1 , and pH 3.5-6.5. The conditions that resulted in higher enzyme activity (1400 U g -1 ) were 70 g L -1 lactose, 65 g L -1 CSL, 4 g L -1 Prodex-lac and pH 5, yielding 61 U L -1 h -1 .