Sustainable strategies to achieve industrial ethanol titers from different bioenergy feedstocks: scale-up approach for better ethanol yield

Hydrothermal pretreatment is a promising approach to lignocellulosic biomass processing for enzymatic hydrolysis and high-yield bioethanol fermentation, as it reduces downstream inhibitor content and the amount of toxic byproducts generated. In this paper, the ethanol yield and productivity of an engineered xylose-fermenting strain of Saccharomyces cerevisiae were tested on lignocellulosic hydrolysates produced with varying citrate buffer concentration, solid loading, supplemental nitrogen source, and feedstock of origin, and a semi-integrated bioprocess which integrates enzymatic hydrolysis and bioethanol fermentation was developed. The greatest ethanol yields (g_p/g_s) of 0.490 ± 0.008, 0.460 ± 0.001, 0.420 ± 0.002 and 0.410 ± 0.002 were obtained from bioenergy sorghum (BES), Miscanthus × giganteus (MG), energy cane (EC), and oilcane (OC), respectively. In addition, an equivalent of 291 L, 253.54 L, 257.8 L, and 260.3 L of bioethanol were produced per ton of BES, MG, EC, and OC, respectively, by using urea as a nitrogen source in a bioreactor.. Authors: Deshavath, Narendra Naik [University of Illinois Urbana-Champaign, IL (United States); University of Illinois Urbana-Champaign] (ORCID:0000000274327570); Woodruff, William [University of Illinois Urbana-Champaign, IL (United States)] (ORCID:0000000219623836); Singh, Vijay [University of Illinois Urbana-Champaign, IL (United States)] (ORCID:0000000343498681). DOE Contract: SC0018420. Subjects: 09 BIOMASS FUELS; Bioethanol; Fermentation; Hydrothermal pretreatment; Lignocellulosic feedstocks; integrated bioprocessing