Bioresource Technology, Vol.135, 350-356, 2013
Batch and multi-step fed-batch enzymatic saccharification of Formiline-pretreated sugarcane bagasse at high solid loadings for high sugar and ethanol titers
Formiline pretreatment pertains to a biomass fractionation process. In the present work, Formiline-pretreated sugarcane bagasse was hydrolyzed with cellulases by batch and multi-step fed-batch processes at 20% solid loading. For wet pulp, after 144 h incubation with cellulase loading of 10 FPU/g dry solid, fed-batch process obtained similar to 150 g/L glucose and similar to 80% glucan conversion, while batch process obtained similar to 130 g/L glucose with corresponding similar to 70% glucan conversion. Solid loading could be further increased to 30% for the acetone-dried pulp. By fed-batch hydrolysis of the dried pulp in pH 4.8 buffer solution, glucose concentration could be 247.3 +/- 1.6 g/L with corresponding 86.1 +/- 0.6% glucan conversion. The enzymatic hydrolyzates could be well converted to ethanol by a subsequent fermentation using Saccharomices cerevisiae with ethanol titer of 60-70 g/L. Batch and fed-batch SSF indicated that Formiline-pretreated substrate showed excellent fermentability. The final ethanol concentration was 80 g/L with corresponding 82.7% of theoretical yield. (C) 2012 Elsevier Ltd. All rights reserved.
Keywords:Lignocellulose;Formiline pretreatment;Enzymatic saccharification;Fed-batch process;High solid loading