Modified simultaneous saccharification and co-fermentation of DLC pretreated corn stover for high-titer cellulosic ethanol production without water washing or detoxifying pretreated biomass

Corn stover (CS) pretreated by DLC (Densifying Lignocellulosic biomass with acidic Chemicals) pre-treatment exhibited higher digestibility and much better fermentability compared to traditional pre-treatments. Nevertheless, the xylose fermentation, which was a key for lignocellulosic ethanol production, during SHCF (Separate Hydrolysis and Co-Fermentation) was unsatisfactory at high solid loadings. In this study, modified SSCF (Simultaneous Saccharification and Co-Fermentation) was adopted to promote xylose utilization and ethanol yield. SSCF conditions (temperature, inoculation size, nitrogen source addition) were investigated. A novel strategy Fed-batch of DLC Biomass and Enzyme (FBE) was developed for SSCF at 28%e35% solid loadings, which showed higher sugar conversion, higher xylose consumption and superior ethanol yield compared to SHCF and traditional SSCF. The highest ethanol titer of 74.6 g/L produced based on DLC pretreatment was achieved during FBE SSCF without water washing or detoxification of DLC-CS. (c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

Corn stover pretreated by DLC exhibited higher digestibility and fermentability compared to traditional pre-treatments. However, the xylose fermentation during SHCF was unsatisfactory at high solid loadings. In this study, modified SSCF was adopted to promote xylose utilization and ethanol yield. A novel strategy, Fed-batch of DLC Biomass and Enzyme (FBE), showed higher sugar conversion, xylose consumption, and superior ethanol yield compared to SHCF and traditional SSCF.