Feasibility of distillers dried grain with solubles (DDGS) for production of cellulase and xylanase enzymes cocktail

Abstract.

The feasibility of co-production of cellulolytic and hemicellulolytic enzymes by Trichoderma reesei using distillers dried grain with solubles (DDGS) was evaluated to improve cost-efficacy of enzymatic hydrolysis of lignocellulosic biomass. The Box-Behnken response surface method was used to examine the effects of solid load of dilute-acid pretreated DDGS and concentrations of peptone and yeast extract and to maximize cellulose and xylanase enzymes in shake-flask submerged fermentation. The experimental results confirmed single enzyme production rather than co-production of both enzymes under the tested culture conditions. Maximal xylanase production of 18.5 IU/mL was predicted with 5% DDGS loading, 0.1 g/L yeast extract, and 2 g/L peptone, whereas highest cellulase production was 1.1 IU/mL when 20% DDGS loading, 1 g/L yeast extract, and 0.5 g/L peptone are used in fermentation medium, according to the statistical analysis of results. The developed linear and quadratic models for cellulase and xylanase production, respectively, were fairly validated in additional trials. Further study is underway to validate and possibly to improve these results in benchtop bioreactors.