Developing Saccharomyces Cerevisiae Strains For Second Generation Bioethanol: Improving Xylose Fermentation And Inhibitor Tolerance

摘要

The 2nd generation bioethanol will be produced from lignocellulose biomass including agricultural residues such as bagasse, straw, and stover, forest products residues and dedicated energy crops. The bioconversion of lignocellulose raw materials to ethanol requires microorganisms that are able (i) to ferment both hexose and pentose sugars present in lignocellulose and (ii) to tolerate and to remain active in presence of inhibiting compounds generated during lignocellulose pretreatment and hydrolysis. In this review we focus on the development of strains of baker's yeast Saccharomyces cerevisiae. We discuss genetic and metabolic engineering strategies that have been used to improve, independently, xylose fermentation and strain tolerance. Then, we deliberate strategies for simultaneous improvement of xylose utilization and inhibitor tolerance, with the view that a new generation of xylose-utilizing S. cerevisiae strains harboring beneficial traits for xylose consumption and inhibitor tolerance is expected to be available in the foreseeable future.