The use of dried spent yeast as a low-cost nitrogen supplement in ethanol fermentation from sweet sorghum juice under very high gravity conditions
Electron. j. biotechnol
;
14(6): 3-3, Nov. 2011. ilus, tab
Article
in English
| LILACS
| ID: lil-640520
ABSTRACT
Dried spent yeast (DSY) was used as a low-cost nitrogen supplement for ethanol fermentation from sweet sorghum juice under very high gravity (VHG) conditions by Saccharomyces cerevisiae NP 01. The fermentation was carried out at 30ºC in a 5-litre bioreactor. The results showed that DSY promoted ethanol production efficiencies. The ethanol concentration (P), productivity (Qp) and yield (Yp/s) of the sterile juice (total sugar of 280 g l-1) supplemented with 8 g l-1 of DSY were not different from those supplemented with yeast extract and/or peptone at the same amount. The initial yeast cell concentration of 5 x 10(7) cells ml-1 was found to be optimal for scale-up ethanol production. In addition, an increase in sugar concentration in inoculum preparation medium (from 10 to 100 g l-1) improved the ability of the inoculum to produce ethanol under the VHG conditions. When S. cerevisiae NP 01 grown in the juice containing 100 g l-1 of total sugar was used as the inoculum for ethanol fermentation, the P, Qp and Yp/s obtained were 108.98 +/- 1.16 g l-1, 2.27 +/- 0.06 g l-1 h-1 and 0.47 +/- 0.01 g g-1, respectively. Similar results were also observed when the ethanol fermentation was scaled up to a 50-litre bioreactor under the same conditions. The cost of the sweet sorghum for ethanol production was US$ 0.63 per litre of ethanol. These results clearly indicate the high potential of using sweet sorghum juice supplemented with DSY under VHG fermentation for ethanol production in industrial applications.
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LILACS (Americas)
Main subject:
Saccharomyces cerevisiae
/
Hypergravity
/
Sorghum
/
Ethanol
/
Fermentation
/
Nitrogen
Type of study:
Health economic evaluation
Language:
English
Journal:
Electron. j. biotechnol
Journal subject:
Biotechnology
Year:
2011
Type:
Article
/
Project document
Affiliation country:
Thailand
Institution/Affiliation country:
Khon Kaen University/TH
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