Recombinant enzyme expression and consolidated bioprocessing by Saccharomyces cerevisiae

Abstract

Lignocellulosic biomass, a rich and inexpensive source of fermentable and renewable carbon, is the most abundant material on earth. Microbial bioprocessing of lignocellulosic biomass to produce biofuels (bioethanol, biobutanol, biodiesel) is a sustainable blueprint towards conserving our fossil fuel reserves and reducing the associated carbon footprint. Saccharomyces cerevisiae, being an excellent industrial ethanologenic organism, is an ideal candidate to engineer as a consolidated bio-processing (CBP) host, a concept that integrates the different steps of cellulosic ethanol production, from hydrolysis of cellulose to glucose and fermentation of glucose to ethanol in one step. In this study, a multifaceted approach has been adopted to improve the cost of cellulosic ethanol production by (i) engineering a potential CBH candidate for improving its catalytic properties and thermal tolerance, (ii) optimizing the synergy of different cellulases for degradation of a widely produced lignocellulosic biomass, corncob and (iii) engineering a robust S. cerevisiae host for ethanol fermentation suitable for CBP application. newline