Highly efficient conversion of sugarcane bagasse pretreated with liquid hot water into ethanol at high solid loading

ABSTRACT

Liquid hot water (LHW), an environmental-friendly physico-chemical treatment, was applied to pretreat the sugarcane bagasse (SCB). Tween80, a non-ionic surfactant, was used to enhance the enzymatic hydrolysis of the pretreated SCB. It found that 0.125 mL Tween80 /g dry matter could make the maximum increase (33.2%) of the glycan conversion of the LHW-pretreated SCB. A self-designed laboratory facility with a plate-and-frame impeller was applied to conduct batch hydrolysis, fed-batch hydrolysis, and the process of high-temperature (50°C) fed-batch hydrolysis following low-temperature (30°C) simultaneous saccharification and fermentation (SSF) which was adopted to overcome the incompatible optimum temperature of saccharification and fermentation in the SSF process. After hydrolyzing LHW-pretreated SCB for 120 h with commercial cellulase, the total sugar concentration and glycan conversion obtained from fed-batch hydrolysis were 91.6 g/L and 68.3%, respectively, which were 9.7 g/L and 7.3% higher than those obtained from batch hydrolysis. With Saccharomyces cerevisiae Y2034 fermenting under the non-sterile condition, the ethanol production and theoretical yield obtained from the process of SSF after fed-batch hydrolysis were 55.4 g/L and 88.3% for 72h, respectively, which were 15.5 g/L and 24.7% higher than those from separate fed-batch hydrolysis and fermentation. The result of this work was superior to the reported results obtained from the LHW-pretreated SCB.

KEYWORDS:

• Ethanol
• fed-batch hydrolysis
• liquid hot water
• simultaneous saccharification and fermentation
• sugarcane bagasse

Funding

The authors gratefully acknowledge the financial supports of the National Basic Research Program of China (no.2012CB215304), the National Key Technologies R&D Program (2011BAD22B01) and the National Natural Science Foundation (51176196).

Additional information

Funding

The authors gratefully acknowledge the financial supports of the National Basic Research Program of China (no.2012CB215304), the National Key Technologies R&D Program (2011BAD22B01) and the National Natural Science Foundation (51176196).