Optimization of Agitation and Aeration for Very High Gravity Ethanol Fermentation from Sweet Sorghum Juice by Saccharomyces cerevisiae Using an Orthogonal Array Design

Naulchan Khongsay, Lakkana Laopaiboon, Prasit Jaisil and Pattana Laopaiboon
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Naulchan Khongsay: Graduate School, Khon Kaen University (KKU), Khon Kaen 40002, Thailand
Lakkana Laopaiboon: Department of Biotechnology, Faculty of Technology, Khon Kaen University (KKU), Khon Kaen 40002, Thailand
Prasit Jaisil: Department of Plant Science and Agricultural Resources, Faculty of Agriculture, Khon Kaen University (KKU), Khon Kaen 40002, Thailand
Pattana Laopaiboon: Department of Biotechnology, Faculty of Technology, Khon Kaen University (KKU), Khon Kaen 40002, Thailand

Energies, 2012, vol. 5, issue 3, 1-16

Abstract: Optimization of three parameters: agitation rate (A; 100, 200 and 300 rpm), aeration rate (B; 0.5, 1.5 and 2.5 vvm) and aeration timing (C; 2, 4 and 6 h), for ethanol production from sweet sorghum juice under very high gravity (VHG, 290 g L ?1 of total sugar) conditions by Saccharomyces cerevisiae NP 01 was attempted using an L 9 (3 4 ) orthogonal array design. The fermentation was carried out at 30 °C in a 2-L bioreactor and the initial yeast cell concentration was approximately 2 × 10 7 cells mL ?1 . The results showed that the optimum condition for ethanol fermentation should be A 2 B 3 C 2 corresponding to agitation rate, 200 rpm; aeration rate, 2.5 vvm and aeration timing, 4 h. The verification experiments under the optimum condition clearly indicated that the aeration and agitation strategies improved ethanol production. The ethanol concentration ( P ), productivity ( Q p ) and ethanol yield ( Y p/s ) were 132.82 ± 1.06 g L ?1 , 2.55 ± 0.00 g L ?1 h ?1 and 0.50 ± 0.00, respectively. Under the same condition without aeration (agitation rate at 200 rpm), P and Q p were only 118.02 ± 1.19 g L ?1 and 2.19 ± 0.04 g L ?1 h ?1 , respectively while Y p/s was not different from that under the optimum condition.

Keywords: aeration; agitation; ethanol fermentation; orthogonal array design; Saccharomyces cerevisiae; very high gravity (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: 2012
References: View complete reference list from CitEc
Citations: View citations in EconPapers (6)

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