Insights into ferulic acid detoxification mechanism by using a novel adsorbent, AEPA250: The microinteraction of ferulic acid with AEPA250 and Saccharomyces cerevisiae

Abstract

In this study, a novel adsorbent, Air Environment-prepared Adsorbent at 250 ℃ (AEPA250), was used to detoxify the main fermentation inhibitor (ferulic acid) present in the alkali-pretreated hydrolysate. AEPA250 reduced the effective concentration of ferulic acid by its adsorption, thereby decreasing the possible interaction of ferulic acid with Saccharomyces cerevisiae. The results indicated that AEPA250 functionalized with hydroxyl, carboxyl, and amino groups under acidic conditions with higher binding energies (−45.667, −27.046, and −11.008 kcal mol−1, respectively) and electronic cloud overlap and shorter bond distances (1.015, 1.010, and 2.094 Å, respectively) than those under the other pH conditions. These differences revealed that the electrostatic interaction dominated ferulic acid adsorption on AEPA250. Additionally, under acidic conditions and for carboxyl group functionalized AEPA250, energy band gap values of Eg1 were higher than those of Eg2, indicating that ferulic acid provided the π-electrons for the π-π electron donor-acceptor interactions with AEPA250. Furthermore, ferulic acid detoxification after AEPA250 adsorption caused the regulation of YDR316W-B and YPR137C-B genes of S. cerevisiae. These results might contribute to the development of other more efficient adsorbents and pretreatment methods and allow yeast engineering for improving the scale-up and self-sufficient production of bioethanol in the future.