Development of a polysaccharide degrading strain of Saccharomyces cerevisiae

Saccharomyces cerevisiae lacks most of the depolymerising enzymes required for efficient hydrolysis and utilisation of polysaccharide-rich biomass. To allow extracellular degradation of polysaccharides, genes encoding amylopullulanase (LKA1), pectate lyase (PEL5), polygalacturonase (PEH1), endo-β-1,4-D-glucanase (END1), cellobiohydrolase (CBH1), exo-β-1,3-D-glucanase (EXG1), cellobiase (β-glucosidase; BGL1) and endo-β-D-xylanase (XYN4) were introduced jointly into a laboratory strain of S. cerevisiae. These transformants were able to grow on starch, pectate, cellobiose and to some extent on cellulose (solka-floc and lichenan). These results pave the way for the development of one-step bioconversion processing of plant biomass in the fuel, animal feed, baking and beverage industries.