Construction of rDNA-mediated stable expression vectors in Saccharomyces cerevisiae
rDNA介导的酿酒酵母稳定表达载体的构建

A fragment containing ori of ColE1 and bla gene was inserted in the EcoR I or Hpa I site of the rRNA gene segment from Saccharomyces cerevisiae, respectively. Based on the expression vector pYES2 and the above two recombinant fragments, two novel rDNA-mediated stable expression vectors, designated as pHBM367E/H, were constructed. The glucoamylase gene from Aspergillus niger was inserted into the vector pHBM367H and the resultant plasmid was named pHBM166. For bio-safety consideration, the plasmid pHBM166 was linearized by Hpa I digestion to remove ColE1 ori and bla gene. Digested product was transformed into S. cerevisiae Y33. Transformants showed different expression levels of glucoamylase. Stability research showed that the selected transformant can express glucoamylase stably in S. cerevisiae for at least 80 generations.