HIGH LEVEL PRODUCTION OF SWINE GROWTH HORMONE

摘要

A high-density fermentation process for high yield production of swine growth hormone by transformant E. coli is described. The process employs transformant strains of E. coli containing an expression vector coding for swine growth hormone under the control of a bacteriophage lambda promoter-operator and an expression vector coding for the .lambda.cI857 temperature-sensitive repressor protein. In the initial growth period, the level of dissolved oxygen in the fermentation medium is maintained at about 20% to 60% saturation and the temperature of the medium is kept between 26.degree.C and 30.degree.C. Production of swine growth hormone is then induced by raising the temperature of the medium to about 40.degree.C. The temperature is then reduced to about 40.degree.C to optimize cell growth for the remainder of the induction period, during which the level of dissolved oxygen in the medium is maintained at about 10% to 40% saturation.