Optimization of saccharification of enzymatically pretreated sugarcane tops by response surface methodology for ethanol production

ABSTRACT

The world's concern over its dependency on non-renewable fossil fuels has drawn our focus towards renewable fuels such as bioethanol from lignocellulosic biomass. The present study investigated the potential of sugarcane tops as a potent source for bioethanol production. Enzymatically pretreated sugarcane tops were subjected to saccharification process using a cellulase-xylanase concoction produced from Trichoderma reesei Rut C30. Statistical analysis using response surface methodology (RSM) was adopted for optimizing the process parameters in order to obtain maximum reducing sugar. Under the optimized conditions of pH 5, incubation 7 h, enzyme titre of 19.33 IU ml^–1, temperature 50°C and solid loading of 14% (w/v), maximum reducing sugar of 508.92 ± 0.02 mg g^–1 was obtained. Changes in the functional group and calorific content after saccharification was also evaluated using FTIR and bomb calorimeter. The hydrolysate obtained after saccharification was further subjected to fermentation using Saccharomyces cerevisiae which was able to produce an ethanol yield of 27.2 g l^–1.

KEYWORDS:

• Sugarcane tops
• saccharification
• response surface methodology
• fermentation

Acknowledgement

The authors would like to express their gratitude to the Ministry of New and Renewable Energy (MNRE, Ref No. 10/14/2010-P&C) for financial assistance to Ms Knawang C. Sherpa for carrying out this work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Ministry of New and Renewable Energy [grant number 10/14/2010-P&C].