Development of Metabolically Engineered Yeast Strains for Efficient Ethanol Production from Lignocellulose

Abstract

To build an energy and material secure future, a next generation of renewable fuels and bio-based chemicals produced from lignocellulosic biomass is required. Consolidated bioprocessing (CBP), which integrates enzyme production, saccharification and fermentation into a single process, is a promising strategy for effective production of bio-based materials. As a key technology for the development of recombinant cellulolytic microbial strains, cell surface engineering, which enables the display through genetic engineering of various types of functional proteins on microbial cell surfaces without loss of their function, is a promising tool reducing the requirement for cellulase addition, as cellulases can be displayed on the microbial cell surface. Regardless of the process used for the biomass hydrolysis, CBP-enabling microorganisms encounter a variety of toxic compounds released during biomass pretreatment that inhibit microbial growth and ethanol yield. Systems biology approaches including transcriptomics and metabolomics have been recently exploited to gain insight into the molecular and genetic traits involved in tolerance and adaptation to the fermentation inhibitors. A combination of a cell surface displayed enzyme system and an intracellular metabolic engineering system is a very effective approach to develop cells with novel fermentation ability for industrial applications.