Evaluation of Consolidated Bioprocessing of Sugarcane Biomass by a Multiple Hydrolytic Enzyme Producer Saccharomyces Yeast

Overcoming key bottlenecks for 2G ethanol production, such as the most suitable biomass pretreatment, process layout, and appropriate microorganism, is crucial to achieve a technically and economically feasible technology. The consolidated bioprocessing (CBP) is an approach that embodies one single step of enzyme production, biomass hydrolysis, and sugars fermentation. In this work, the CBP using S. cerevisiae AC14, a recombinant strain capable of secreting 7 different lignocellulosic enzymes and ferment xylose and glucose, was investigated in synthetic medium (cellobiose, corncob xylan, glucose, and xylose) and in industrial medium consisting of the solid fraction of hydrothermally pretreated sugarcane bagasse and its liquor. Results obtained were promising, with ethanol productivity of 4.46 g/L/h and complete hydrolysis of cellobiose and corncob xylan. In real industrial medium, 1.86 g/L/h of ethanol was reached, with partial conversion of both solid and liquid fractions. Further strategies to enhance enzymes access to complex substrates can improve process feasibility.