CULTIVATION OF TRANSFORMED YEAST

摘要

PURPOSE:A yeast which has been transformed with a recombined plasmid including genes of hepatitis virus B is cultured to produce surface antigen to hepatitis virus B where a semi-synthetic culture medium of a specific composition is used to improve the yield. CONSTITUTION:The gene of hepatitis virus B is introduced into the plasmid bearing inhibitory acidic phosphatase promotor in a yeast under the control of the promotor. The recombined plasmid is used to transform a yeast such as Saccharomyces cerevisiae AH22. Then, the transformed yeast is cultured in a semi-synthetic medium containing yeast essence, inorganium ammonium salt such as ammonium sulfate or chloride, inorganic magnesium such as magnesium sulfate and glucose or saccharose or both of them to produce surface antigen of hepatitis virus B in high efficiency.