ISSN 2736-1756
Advanced Journal of Microbiology Research Vol. 2011
Available online at http://internationalscholarsjournals.org/journal/ajmr
© 2011 International Scholars Journals
Full Length Research Paper
The surface display of phytase on yeast cell and activity assay of the displayed protein
Shumin Yao*, Jing Huang and Jingli Tan
College of Life Science, Qufu Normal University, Qufu 273165, People’s Republic of China.
Accepted 05 June, 2011
Abstract
Phytase is a new-style enzyme used in animal feed additive. It can increase phosphorus availability, decrease environmental phosphorus pollution and improve the performance of animals. Phytase gene was cloned by reverse transcription-polymerase chain reaction (RT-PCR) using first strand cDNA as template after reverse transcripting Aspergillus niger total RNA. The phyA gene was cloned into plasmid pYD1 which allows regulated expression, secretion and detection of expressed proteins on the surface of Saccharomyces cerevisiae cells using immunofluorescence. The construct was propagated in Escherichia coli DH5α and then was transformed into the yeast strain EBY100. After induction, the phytase activity was measured every 12 h. The results indicated that the activity of the fusion protein reached the highest level after being induced with 2.0% galactose for 48 h. This enzyme had pH optima (pH 7) and its optimum temperature was about 65°C.
Key words: Yeast surface display, Aspergillus niger, phytase.