Effects of glycerol on enzymatic hydrolysis and ethanol production using sugarcane bagasse pretreated by acidified glycerol solution

• Published in: Bioresource technology Vol. 192; pp. 367 - 373
• Main Authors: Zhang, Zhanying, Wong, Heng H., Albertson, Peter L., Harrison, Mark D., Doherty, William O.S., O’Hara, Ian M.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-09-2015
• Subjects: Biomass; Biotechnology - methods; Cellulose - chemistry; Cellulose - metabolism; Enzymatic hydrolysis; Ethanol - metabolism; Fermentation; Glucans - metabolism; Glycerol; Glycerol - chemistry; Hydrolysis; Ionic Liquids - chemistry; Pilot Projects; Pretreatment; Saccharum - chemistry; Saccharum - metabolism; Sugarcane bagasse; Yeasts - metabolism; Glycerol; Pretreatment; Fermentation; Enzymatic hydrolysis; Sugarcane bagasse
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2015.05.093

•2.0wt% glycerol inhibited glucan digestibility by 2.0%.•Up to 5.0wt% glycerol had no effect on subsequent yeast fermentation.•Glycerol is a less potent inhibitor of enzymes and yeast than ionic liquids.•Pilot-scale ethanol production was demonstrated with 5.51wt% residual glycerol.•An ethanol yield of 0.142kg/kg dry bagasse can be achieved.
In this study, for the first time the effects of glycerol on enzymatic hydrolysis and ethanol fermentation were investigated. Enzymatic hydrolysis was inhibited slightly with 2.0wt% glycerol, leading to reduction in glucan digestibility from 84.9% without glycerol to 82.9% (72h). With 5.0wt% and 10.0wt% glycerol, glucan digestibility was reduced by 4.5% and 11.0%, respectively. However, glycerol did not irreversibly inhibit cellulase enzymes. Ethanol fermentation was not affected by glycerol up to 5.0wt%, but was inhibited slightly at 10.0wt% glycerol, resulting in reduction in ethanol yield from 86.0% in the absence of glycerol to 83.7% (20h). Based on the results of laboratory and pilot-scale experiments, it was estimated that 0.142kg ethanol can be produced from 1.0kg dry bagasse (a glucan content of 38.0%) after pretreatment with acidified glycerol solution.