The Research On The Medium Optimization And The Fermenter Liquid Fermentation Of Recombinant Porcine Growth Hormone Genetically Engineered Strain

In most cases, fermenter fermentation medium for Pichia pastoris uses the salt-based medium or BMGY / BMMY medium based on the Pichia Fermentation Process Manual of the Invitrogen Company. The composition of the salt-based medium was complex, and most of the components was salt. So the nutrient of the medium was defective, and the price was relatively high, especially that such medium can not be mixed or high-temperature sterilization. Otherwise they were easy to form deposits. In this paper, the fermenter fermentation medium of the genetic engineered strains was optimized. In addition, the optimized conditions of the fermenter fermentation were determined in order to reduce the cost of industrial production of porcine growth hormone.(1) In this study, we served potato pulp hydrolysate as basic carbon source and bean dregs hydrolysate as basic nitrogen source, and we adopted the orthogonal experiment to optimize the medium of Pichia pastoris containing porcine growth hormone. As the result, in 100ml optimized medium, the amount of potato pulp hydrolysate was 12ml, the amount of bean dregs hydrolysate was 25ml, the amount of K₂HPO₄ was 0.5g, and the amount of wheat bran hydrolysate was 0.8ml. We adopted such optimized medium to turn sour the selected high product recombinant porcine growth hormone genetically engineered strain, after 60h induction, the final harvest of total protein of the supernatant up to 78.4mg/L. Then, we adopted wort medium with the same culture and induction conditions, the final harvest of total protein of the supernatant was 88.4mg / L. Also, the cost of such medium which was optimized and suitable for Pichia pastoris growth and expression was 2.3% of the working medium cost and was 8642.6 times cheaper than BMGY / BMMY medium. It greatly reduced the cost of industrial produce. We have acquired high quality and cheap industrial used high-density liquid fermentation medium.(2)By the study of the inoculation amount, induction time, the initial pH and other conditions, we determined the optimal fermentation conditions of the genetic engineered strains of Pichia pastoris. That was l0% inoculation, at 8.0 of the initial pH, and 60h induction time. Under these conditions, the protein concentration of the fermentation supernatant was 78.4mg / L.