Sugar-rich sweet sorghum is distinctively affected by wall polymer features for biomass digestibility and ethanol fermentation in bagasse

• DOI: 10.1016/j.biortech.2014.04.086
• Publication Date: 2014-05-10T18:00:19Z
• Authors: Meng Li; Shengqiu Feng; Leiming Wu; Ying Li; Chunfen Fan; Rui Zhang; Weihua Zou; Yuanyuan Tu; Hai-Chun Jing; Shizhong Li; Liangcai Peng
• Keywords: 2. Zero hunger; Ethanol; Carbohydrates; Saccharomyces cerevisiae; Lignin; 01 natural sciences; Biopolymers; Cellulase; Solubility; Cell Wall; Biofuels; Fermentation; Carbohydrate Metabolism; Biomass; Cellulose; Sorghum; 0105 earth and related environmental sciences

Sweet sorghum has been regarded as a typical species for rich soluble-sugar and high lignocellulose residues, but their effects on biomass digestibility remain unclear. In this study, we examined total 63 representative sweet sorghum accessions that displayed a varied sugar level at stalk and diverse cell wall composition at bagasse. Correlative analysis showed that both soluble-sugar and dry-bagasse could not significantly affect lignocellulose saccharification under chemical pretreatments. Comparative analyses of five typical pairs of samples indicated that DP of crystalline cellulose and arabinose substitution degree of non-KOH-extractable hemicelluloses distinctively affected lignocellulose crystallinity for high biomass digestibility. By comparison, lignin could not alter lignocellulose crystallinity, but the KOH-extractable G-monomer predominately determined lignin negative impacts on biomass digestions, and the G-levels released from pretreatments significantly inhibited yeast fermentation. The results also suggested potential genetic approaches for enhancing soluble-sugar level and lignocellulose digestibility and reducing ethanol conversion inhibition in sweet sorghum.