Impact of cultivar selection and process optimization on ethanol yield from different varieties of sugarcane
Date
2014-04
Authors
Benjamin, Yuda
Garcia-Aparicio, Maria. P.
Gorgens, Johann. F.
Journal Title
Journal ISSN
Volume Title
Publisher
BioMed Central
Abstract
Background: The development of ‘energycane’ varieties of sugarcane is underway, targeting the use of both sugar
juice and bagasse for ethanol production. The current study evaluated a selection of such ‘energycane’ cultivars for
the combined ethanol yields from juice and bagasse, by optimization of dilute acid pretreatment optimization of
bagasse for sugar yields.
Method: A central composite design under response surface methodology was used to investigate the effects of
dilute acid pretreatment parameters followed by enzymatic hydrolysis on the combined sugar yield of bagasse
samples. The pressed slurry generated from optimum pretreatment conditions (maximum combined sugar yield) was
used as the substrate during batch and fed-batch simultaneous saccharification and fermentation (SSF) processes at
different solid loadings and enzyme dosages, aiming to reach an ethanol concentration of at least 40 g/L.
Results: Significant variations were observed in sugar yields (xylose, glucose and combined sugar yield) from
pretreatment-hydrolysis of bagasse from different cultivars of sugarcane. Up to 33% difference in combined sugar yield
between best performing varieties and industrial bagasse was observed at optimal pretreatment-hydrolysis conditions.
Significant improvement in overall ethanol yield after SSF of the pretreated bagasse was also observed from the best
performing varieties (84.5 to 85.6%) compared to industrial bagasse (74.5%). The ethanol concentration showed inverse
correlation with lignin content and the ratio of xylose to arabinose, but it showed positive correlation with glucose
yield from pretreatment-hydrolysis. The overall assessment of the cultivars showed greater improvement in the final
ethanol concentration (26.9 to 33.9%) and combined ethanol yields per hectare (83 to 94%) for the best performing
varieties with respect to industrial sugarcane.
Conclusions: These results suggest that the selection of sugarcane variety to optimize ethanol production from
bagasse can be achieved without adversely affecting juice ethanol and cane yield, thus maintaining first generation
ethanol production levels while maximizing second generation ethanol production.
Description
Publication of this article was funded by the Stellenbosch University Open Access Fund.
The original publication is available at http://www.biotechnologyforbiofuels.com/content/7/1/60
The original publication is available at http://www.biotechnologyforbiofuels.com/content/7/1/60
Keywords
Sugar cultivar selection, Ethanol production, Sugarcane
Citation
Benjamin, Y., Garcia-Aparicio, M. P. & Gorgens, J.F. 2014. Impact of cultivar selection and process optimization on ethanol yield from different varieties of sugarcane. Biotechnology for Biofuels, 7:60, doi:10.1186/1754-6834-7-60.