Batch and multi-step fed-batch enzymatic saccharification of Formiline-pretreated sugarcane bagasse at high solid loadings for high sugar and ethanol titers

Abstract

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 ~150. g/L glucose and ~80% glucan conversion, while batch process obtained ~130. g/L glucose with corresponding ~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. © 2012 Elsevier Ltd.