High Level Ethanol Production by Nitrogen and Osmoprotectant Supplementation under Very High Gravity Fermentation Conditions

Pachaya Chan-u-tit, Lakkana Laopaiboon, Prasit Jaisil and Pattana Laopaiboon
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Pachaya Chan-u-tit: Graduate School, Khon Kaen University, Khon Kaen 40002, Thailand
Lakkana Laopaiboon: Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002, Thailand
Prasit Jaisil: Department of Plant Science and Agricultural Resources, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand
Pattana Laopaiboon: Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002, Thailand

Energies, 2013, vol. 6, issue 2, 1-16

Abstract: Optimization of nutrient supplements i.e. , yeast extract (1, 3 and 5 g·L −1 ), dried spent yeast (DSY: 4, 12 and 20 g·L −1 ) and osmoprotectant (glycine: 1, 3 and 5 g·L −1 ) to improve the efficiency of ethanol production from a synthetic medium under very high gravity (VHG) fermentation by Saccharomyces cerevisiae NP 01 was performed using a statistical method, an L 9 (3 4 ) orthogonal array design. The synthetic medium contained 280 g·L −1 of sucrose as a sole carbon source. When the fermentation was carried out at 30 °C, the ethanol concentration ( P ), yield ( Y p/s ) and productivity ( Q p ) without supplementation were 95.3 g·L −1 , 0.49 g·g −1 and 1.70 g·L −1 ·h −1 , respectively. According to the orthogonal results, the order of influence on the P and Q p values were yeast extract > glycine > DSY, and the optimum nutrient concentrations were yeast extract, 3; DSY, 4 and glycine, 5 g·L −1 , respectively. The verification experiment using these parameters found that the P , Y p/s and Q p values were 119.9 g·L −1 , 0.49 g g −1 and 2.14 g·L −1 ·h −1 , respectively. These values were not different from those of the synthetic medium supplemented with 9 g·L −1 of yeast extract, indicating that DSY could be used to replace some amount of yeast extract. When sweet sorghum juice cv. KKU40 containing 280 g·L −1 of total sugar supplemented with the three nutrients at the optimum concentrations was used as the ethanol production medium, the P value (120.0 g·L −1 ) was not changed, but the Q p value was increased to 2.50 g·L −1 ·h −1 .

Keywords: bioethanol; nutrient supplements; orthogonal array design; osmoprotectant; very high gravity (VHG) fermentation; Saccharomyces cerevisiae (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2013
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (4)

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