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

Energies

Naulchan Khongsay¹  Lakkana Laopaiboon³  Prasit Jaisil² 

[1] Graduate School, Khon Kaen University (KKU), Khon Kaen 40002, Thailand; E-Mail:;Department of Plant Science and Agricultural Resources, Faculty of Agriculture, Khon Kaen University (KKU), Khon Kaen 40002, Thailand; E-Mail:;Department of Biotechnology, Faculty of Technology, Khon Kaen University (KKU), Khon Kaen 40002, Thailand; E-Mail:

关键词: aeration;    agitation;    ethanol fermentation;    orthogonal array design;    Saccharomyces cerevisiae;    very high gravity;   

DOI  :  10.3390/en5030561

来源: mdpi

【 摘 要 】

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 L₉ (3⁴) 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 × 10⁷ cells mL⁻¹. The results showed that the optimum condition for ethanol fermentation should be A₂B₃C₂ 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⁻¹h⁻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⁻¹h⁻¹, respectively while Y_p/s was not different from that under the optimum condition.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.