Ex Vivo Enzymatic Conversion of Non-food Cellulose Biomass to Starch

Abstract

To meet the world's rising future food/feed needs, outputs of modern agriculture must grow substantially while minimizing agriculture's environmental footprint and conserving biodiversity. In this chapter, we propose an ex vivo synthetic enzymatic pathway to enable the transformation of non-food cellulose to amylose, a high-value linear starch, meanwhile glucose released by enzymatic hydrolysis of cellulose is used to produce ethanol and/or single-cell protein by yeast fermentation in the same vessel. The strategy of simultaneous enzymatic biotransformation and microbial fermentation is the basis of new biomass biorefineries that would address the food, fuels, and environment trilemma by coproducing food/feed, biomaterials, and biofuels from the most abundant renewable bioresource-non-food lignocellulosic biomass. Toward this development, new directions pertaining to pretreatment of lignocellulosic biomass and advanced enzyme engineering are discussed to increase the efficiency of saccharification.