Minimizing the enzyme dosage for ethanol production from cellulose‐rich bagasse residues after furfural production

Abstract Through consolidated bioprocessing, cellulosic ethanol production from sugarcane bagasse residues emanating from furfural production (furfural residues, FRs) may offer substantial cost reductions compared with conventional pretreatment–hydrolysis–fermentation of lignocelluloses. Furfural residues have a high enzymatic digestibility and require little to no pretreatment before hydrolysis–fermentation, while the application of advanced, cellulase‐secreting yeasts minimizes exogenous enzyme supplementation. Fed‐batch bioconversion of water‐washed FRs through simultaneous saccharification and fermentation using 25% w/w total solid loading and an exogenous cellulase dosage of 1.5 filter paper units g −1 dry solids (10.9 mg protein g −1 cellulose), together with the cellulase‐secreting strain of Saccharomyces cerevisiae Cellusec® 3.3, resulted in 40.8 g L −1 ethanol at 53.7% of the theoretical maximum yield. The acceptable hydrolysis–fermentation of FRs at low enzyme dosages though consolidated bioprocessing demonstrated the industrial attractiveness of the feedstock for cellulosic ethanol production.