Response surface methodology as an approach to determine the optimal activities of xylose reductase and xylitol dehydrogenase enzymes from Candida Mogii

• Grant number: 07/00249-8
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Start date: March 01, 2007
• End date: May 31, 2007
• Field of knowledge: Engineering - Chemical Engineering - Chemical Process Industries
• Principal Investigator: Ines Conceicao Roberto
• Grantee: Ines Conceicao Roberto
• Host Institution: Escola de Engenharia de Lorena (EEL). Universidade de São Paulo (USP). Lorena , SP, Brazil

Abstract

A central composite experimental design was performed to attain the optimal activities of xylose reductase (XR) and xylitol dehydrogenase (XDH) enzymes from Candida mogii cell extract. Under optimized conditions (pH 6.5 and 38C), the XR and XDH activities were found to be 0.48 U/mL and 0.22 U/ml, respectively. Stability, cofactor specificity and kinetic parameters of the enzyme XR were also evaluated. XR activity remained stable for 3h under 4 and 38C and for 4 months of storage at -18C. Studies on cofactor specificity showed that only NADPH-dependent XR was obtained under the cultivation conditions. Km values was not modified after enzyme extraction by aqueous two-phase system. (AU)