Patents
The invention provides the construction of an expression vector containing a strong promoter, which provides continuous, high level expression of heterologous genes, or synthetic gene encoding therapeutic protein such as Hepatitis B surface antigen, HBsAg, for several days in transformed Schizosaccharomyces pombe strain. Expression levels are further stimulated by 3-fold upon culturing in the presence of 1.2 M sorbitol, yielding intracellular protein expression levels at shake flask that are 60 to 180-fold higher than those achieved with ADH1 and NMT1 promoters of S. pombe and 12 to 18-fold higher than those reported with the Pichia pastoris promoter AOX1. This system has great potential as a commercially viable and more cost effective alternative to Pichia pastoris for expressing heterologous proteins.