Transformation and expression of Penicillium funicolusum glucose oxi- dase gene in yeast

Glucose oxidase is an important enzyme hydrolyzing for its hydrolyzing activity on glucos. It possesses and has a wide board of applications in different industries such as bakery, pharmaceutical, plant pathology and biosensors. In this study, yeast (Saccharomyces cerevisiae) was transformed successfully by the glucose oxidase gene (gox) obtained from Penicillium funicolusum. The secreted glucose oxidase enzyme (GOX) by yeast transformants was characterized intra and extracellularly. The effect of different pH values, carbon sources and the duration of cultivation time on the gene expression were also studied in liquid and solid media. Results indicated that the produced enzyme had the maximum activity of 41and 38 U/ ml for the intra and extracellular, respectively in pHs ranging between 4.5-5.5 at optimum temperature of 30°C after 3 days of yeast culture. Galactose was found to be the most efficient carbon source than the other sources and the maximum activity of target enzyme was observed at 1% (w/v) concentration of galactose. The presence of glucose in the culture media depressed the production of GOX. However, a high rate of growth of the yeast and the high yield of the target enzyme suggested its potential for application in the industry.