Ethanol, methane, or both? Enzyme dose impact on ethanol and methane production from untreated energy crop switchgrass varieties

The production of bioethanol and subsequent methane from two raw switchgrass varieties with the addition of cellulase and beta-glucosidase dose combinations was investigated in this study. Maximum ethanol production increment for the investigated varieties, Shawnee and Kanlow, were determined as 211.9% and 166.7%, respectively, compared to the control assays without enzymes. Considering higher ethanol production a priority, 42.0 mg EtOH/gVS and 223.5 mLCH(4)/gVS were produced from Shawnee variety at 50 EGU cellulase - 80 IU beta-glucosidase doses. 20.2 mgEtOH/gVS, and 400.7 mLCH(4)/gVS were produced from Kanlow variety at 75 EGU cellulase - 80 IU beta-Glucosidase doses. Furthermore, the highest total biofuel energy productions were found as 10750,9 MJ/tonne field dried switchgrass at 75 EGU cellulase - 20 IU beta-glucosidase doses for Shawnee and 13556,9 MJ/tonne field dried switchgrass at 75 EGU cellulase 80 IU beta-glucosidase doses for Kanlow. Shawnee variety was found to be more suitable for cellulosic ethanol production. (C) 2019 Elsevier Ltd. All rights reserved.