The potential of enzyme recycling during the hydrolysis of a mixed softwood feedstock.

Despite recent improvement in cellulase enzymes properties, the high cost associated with the hydrolysis step remains a major impediment to the commercialization of full-scale lignocellulose-to-ethanol bioconversion process. As part of a research effort to develop a commercial process for bioconversion of softwood residues, we have examined the potential for recycling enzymes during the hydrolysis of mixed softwood substrate pretreated by organosolv process. We have used response surface methodology to determine the optimal temperature, pH, ionic strength, and surfactant (Tween 80) concentration for maximizing the recovery of bound protein and enzyme activity from the residual substrates after hydrolysis.

Effect of surfactants on separate hydrolysis fermentation and simultaneous saccharification fermentation of pretreated lodgepole pine.

The effects of surfactants addition on enzymatic hydrolysis and subsequent fermentation of steam exploded lodgepole pine (SELP) and ethanol pretreated lodgepole pine (EPLP) were investigated in this study. Supplementing Tween 80 during cellulase hydrolysis of SELP resulted in a 32% increase in the cellulose-to-glucose yield. However, little improvement was obtained from hydrolyzing EPLP in the presence of the same amount of surfactant.