Secretory expression of glucose oxidase gene in Aspergillus niger

One GOD (Glucose oxidase, 1818bp) gene was cloned from Aspergillus niger and then overlapped extension to obtain 5' homologous arm GLA (saccharifying enzyme) and 3' homologous arm GLA of expressional box of the gene.The whole gene was inserted into expressional vector pSZH to form the homologous recombination expressional vector pSZH-GOD of Aspergillus Niger.Using freeze thawing method pSZH-GOD expressional vector was transformed into Agrobacterium AGLI which transformed into Aspergillus niger which could expressed highly saccharifying enzyme.8 positive transgenic strains were detected by hygromycin selection and PCR.The enzyme activity of eight positive transgenic strains were tested, the result showed that GOD gene was highly expressed in transforming strains whose exocellular enzyme activity were up to 1.166U/mL after 6d static cultivation, while enzyme activity of GOD gene was not detected in non-transformed strains.Meanwhile, endocellular enzyme activity of GOD gene was up to 11.45U/mL which was 266 times that of the starting strains.The result of this study provided a new approach to simplify the GOD fermentational technology to improve the enzyme production.