Glyceraldehyde-3-phosphate Dehydrogenase Promoter Research Articles

Controlled fed‐batch fermentation of recombinant Saccharomyces cerevisiae to produce hepatitis B surface antigen

We have performed controlled fed-batch fermentation experiments to compare the production level of hepatitis B surface antigen (HBsAg) by recombinant yeast Saccharomyces cerevisiae strains (YNN27/pYBH-1, YNN27/ p2micro-S11, YNN27/pDCB-S2) containing plasmid vector with alcohol dehydrogenase (ADH1), acid phosphatase (PHO5), and glyceraldehyde-3-phosphate dehydrogenase (GPD) promoter, respectively. Yeast cell concentrations of 15-35 g dry cell weight/L were obtained. By limiting phosphorous concentration, HBsAg expression level for the YNN27/p2micro-S11 strain with inducible PHO5 promoter reached 0.2-0.3 mg/L. By controlling nutrient addition rate and dissolved oxygen concentration, HBsAg concentrations of 3-10 mg/L were achieved in 60-70 h fermentation using the YNN27/pDCB-S2 strain with the constitutive GPD promoter.

Potassium oxide in California : Anon. ( Oil, Paint, and Drug Rep., Sept. 7, 1914)

The yeast Torulaspora pretoriensis YK-1 possesses both high potential leavening ability and freeze-thaw resistance, but its leavening ability in dough, without the addition of sugar, is much less than commercial baking strains (Oda and Tonomura 1993) Institute for Fermentation, Osaka, Japan (IFO) 0022, another strain of T. pretoriensis, previously found to leaven dough efficiently without the addition of sugar, showed higher activities of both maltose permease and α-glucosidase and fermented maltose in an aqueous medium faster than YK-1. No significant difference was observed between the affinities of maltose permease and α-glucosidase from IFO 0022 and those from YK-1. MAL61 and MAL62 genes of Saccharomyces cerevisiae were expressed in T. pretoriensis YK-1 and elevated the activities of maltose permease and α-glucosidase, respectively, when these genes were introduced on YCp-type plasmids under control of the glyceraldehyde 3-phosphate dehydrogenase promoter. Maltose fermentation by cells harbouring the plasmids carrying either MAL61 or MAL62 genes was slightly stimulated. Introduction of both genes further enhanced the maltose fermentation rate but not leavening ability in dough without the addition of sugar. These results suggest that maltose permease and α-glucosidase determine the overall velocity of maltose fermentation.