%0 Journal Article
%T High Level Ethanol Production by Nitrogen and Osmoprotectant Supplementation under Very High Gravity Fermentation Conditions
%A Pachaya Chan-u-tit
%A Lakkana Laopaiboon
%A Prasit Jaisil
%A Pattana Laopaiboon
%J Energies
%D 2013
%I MDPI AG
%R 10.3390/en6020884
%X 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 ¡ãC, the ethanol concentration ( P), yield ( Yp/s) and productivity ( Qp) 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 Qp 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, Yp/s and Qp 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 Qp value was increased to 2.50 g¡¤L £¿1¡¤h £¿1.
%K bioethanol
%K nutrient supplements
%K orthogonal array design
%K osmoprotectant
%K very high gravity (VHG) fermentation
%K Saccharomyces cerevisiae
%U http://www.mdpi.com/1996-1073/6/2/884