(587aa) Efficient Xylose Consumption Under Inhibitors Derived From Lignocellulose Biomass By Engineered Saccharomyces Cerevisiae Strains

Commercial production of cellulosic ethanol by yeast requires the strains that can ferment both hexose and pentose sugars and that have sufficient tolerance to the inhibitors in pretreated biomass, such as acetic acid and furfural.

We have engineered Saccharomyces cerevisiaefor robust production of ethanol from lignocellulosic biomass by overexpression of genes that encode xylose isomerase and native pentose phosphate pathway enzymes.  To improve the ability of ethanol production, such as sugar utilization efficacy and tolerance to inhibitors, we have applied evolutionary engineering and introduced several additional genes from other microorganisms.

Here we describe efficient cellulosic ethanol production processes have been developed with our yeast strain.  Optimizing processing conditions for the dilute acid pretreatment with steaming of biomass, and combination of saccharification and fermentation, we achieved rapid consumption of xylose and high yield of ethanol from lignocellulosic hydrolysates at low cellulase loading.  For example, using Napier grass (Elephant grass) as a feedstock, we achieved about 70 g/L ethanol production under the condition of 20%TS(w/w).