Cellulosic Ethanol Production through Chemical Detoxification

Cellulosic ethanol production from lignocellulosic biomass offers a sustainable solution for transition from fossil based fuels to renewable alternatives. However, a few long-standing technical challenges remain to be addressed in the development of an economically viable fermentation process from lignocellulose. Such challenges include the needs to improve yeast tolerance to toxic inhibitory compounds and to achieve high fermentation efficiency with minimum detoxification steps after a pretreatment of the biomass. We developed an in-situ detoxification strategy by exo-protection of an industrial dry yeast (starch-base) with polymeric materials that are compatible with the yeast. The exo-protected yeast cells displayed remarkably boosted vitality with high tolerance to toxic inhibitory compounds such as phenolic and furanic compounds, and with largely improved ethanol productivity from crude lignocellulosic hydrolysates derived from pretreated lignocellulose. The chemical exo-protection makes the industrial S. cerevisiae yeast directly applicable for the production of cellulosic ethanol with substantially improved productivity and yield, without of the need to use genetically modified microorganisms.