Study On The Fermentation Technics Of Genetic Engineering Phytase Strain E-22

Phytase is a kind of biological enzyme, which can decompound phytic acid (phytate) and then release the inorganic phosphorus, inositol and protein, amino acid, microelement, combined with phytic acid, etc. The phytase research starts from the 20th century 60's, and now entered to the molecular level. Many kinds of microbial source of phytase have already separated and purified. More and more phytase genes were cloned form different microorganisms. At present, studies on phytase mainly focus on reconstructing phytase gene, change phytase character such as heat resistance, suitable pH, catalyze activity, etc, and improve its utilization efficiency in feed. Other important thing is to clone phytase gene, then highly effective expression in biological reactor. So it can solve the content of the phytase is too low in the natural material to be massively extract. Our laboratory has constructed a genetic engineering phytase strain E-22. Its hereditary stability and enzyme character can well meet production's need. On the basis of studies in our laboratory, following work was done:1. The effect of different fermentation condition: The inoculating time 36h, inoculating amount 10%, multiplication time 72h, fermentation fluid pH 6.0, methanol supply 1.5%, amount of liquid in fermentation pot 10% and time of inducement and expression of 120h can highly improve production of phytase. 164416.7U/mL of the phytase was obtained. It was higher 15% than before. When the fermentation medium was added penicillin, Streptomycin, Triton-114 and Tween-80, It hadn't any promoting effect, instead had some certain inhibitory action.2. The study on suitable carbon source and supply amount suggested that phytase can achieve 96067U/mL and 83458U/mL respectively when use 1% glycerine and 10% malt juice individually. In addition, suitable nitrogen source is studied. Phytase could be obtained 96557U/mL with accession 5% fish powder, and additional 5% peptone 119008 U/mL was obtained. Considering the nutrition source and cost, we used 10% of the malt juices as carbon source and about 5% of fish powder as the nitrogen source. The other fermentation condition did not change. 103275U/mL of phytase was obtained. It indicated that is a good resolution.3. Referenced to optimized fermentation condition in shake flask, we designed that material added in fermentation pot intermittently or did not added, and methanol added intermittently or constantly. The result showed that the material added intermittently and methanol added...