Ameliorated enzymatic saccharification of corn stover with a novel modified alkali pretreatment

Enzymatic saccharification/hydrolysis is one of the key steps for the bioconversion of lignocelluloses into sustainable biofuels. In this work, corn stover was pretreated with a novel modified alkali process (NaOH + anthraquinone (AQ) + sodium lignosulfonate (SLS)), and then enzymatically hydrolyzed with an enzyme cocktail (cellulase (Celluclast 1.5L), β-glucosidase (Novozyme 188) and xylanase (from thermomyceslanuginosus)) in the pH range of 4.0-6.5. It was found that the suitable pH for the enzymatic saccharification process to achieve a high glucan yield was between 4.2 and 5.7, while the appropriate pH to obtain a high xylan yield was in the range of 4.0-4.7. The best pH for the enzymatic saccharification process was found to be 4.4 in terms of the final total sugar yield, as xylanase worked most efficiently in the pH range of 4.0-4.7, under the conditions in the study. The addition of xylanase in the enzymatic saccharification process could hydrolyze xylan in the substrates and reduce the nonspecific binding of cellulase, thus improving the total sugar yields.