Development of a Vector Set for High or Inducible Gene Expression and Protein Secretion in the Yeast Genus

Converting lignocellulosic biomass into value-added products is one of the challenges in developing a sustainable economy. Attempts to engineer fermenting yeasts to recover plant waste are underway. Although intensive metabolic engineering has been conducted to obtain strains capable of metabolising pentose sugars mainly found in hemicellulose, enzymatic hydrolysis after pretreatment is still required. , which naturally assimilates xylose and arabinose and displays numerous glycoside hydrolases, is a good candidate for direct and efficient conversion of renewable biomass. However, a greater diversity of tools for genetic engineering is needed. Here, we report the characterisation of four new promising promoters, a new dominant marker, and two vectors for the secretion of epitope tagged proteins along with a straightforward transformation protocol. The promoter is a constitutive promoter stronger than , and whose activity is maintained at high temperature or in the presence of ethanol. The regulated promoters respond to high temperature for , gluconeogenic sources for or presence of xylose oligomers for . Two expression/secretion vectors were designed based on p and p, two endogenous signal peptides from an α-arabinanase and an α-glucuronidase, and two epitopes. A heterologous α-arabinoxylan hydrolase from was efficiently secreted using these two vectors.