Usami Aspergillus Phya Gene Cloning And Expression

Phytase is the generic name of enzyme which catalyze the hydrolysis of phytate into myo-inositol and phosphate. On one hand phytase can enhance the mono-stomach animal absorbing phosphorus and increase its utilization rate in animal feed about 50% .On the other hand it can degrade the product phytate binded by some multi-metal ions and proteins then accelerate animals' growth and protect ecotypic enviroment. So it has great practical significence and potential application in feed, foods, medicine industry and enviroment conservation.A broad range of micoorganisms, including bacteria, filamentous fungi and yeasts can produce phytases. However, due to the high cost and the weak ermostability of the phytase products, only a limited amout of commercial microbial phytases are used in feedstuff. Thus economical and thermostable phytases are badly required in the feedstuff industry.In this study, the fragment of phyA about 1.3 kb absent sigial sequence and intron was amplified by PCR with primers designed according to published phyA sequences from Aspergillus usamii 2418, it was also cloned and sequenced. This research selected the strong functional Prokaryotic expression vector pET32a+ and Eucaryote expression vector pMET α A. So using the expression vector , successfully constucted the gene engineering strains Ecoli.BL21-pET32a+-phyA and Pichia PMAD-Pmet32a+-phyA. Then we wished to obtain the phytase of mass high activity, obearing acids and good stability. And provided basic datas and science accordings for developing a new type of multi-functional ecological agent, which had much phytase. And supplied some message to realize the green engenering of livestock fanning.