Studies on Solvent Extraction of Ethanol during Fermentation under Agitated Condition

Abstract

In the present investigation, an attempt has been made to study the effect of agitation on simultaneous fermentation and extraction of ethyl alcohol in the presence of ethyl benzene as solvent. Three separate studies, viz. agitation of both the aqueous and non-aqueous phases at the same rotational speed of agitator (the range being 100–300 rpm), agitation of the non-aqueous phase keeping the aqueous phase static and agitation during fermentation in the absence of solvent, were carried out. In each case, Sacchoromyces cerevisiae was used as the microorganism in the production media with 10% (w/v) glucose as substrate at 30°C. It was observed that, in general, an increase in agitator speed decreased ethanol production under a solvent-free system. Under the aqueous phase static and organic phase agitated conditions, the maximum yield of ethanol in aqueous phase was obtained at a 200 rpm agitator speed after 12 h of incubation. It was further noticed that extraction of ethanol in the organic phase increased marginally when the agitator speed increased from 200 to 300 rpm after 20 h of incubation. With both phases agitated at the same agitator speed, the yield of ethanol in the organic phase increased appreciably after 200 rpm. Notably, no extraction of ethanol in organic phase was observed below 200 rpm. In the aqueous phase, the yield of ethanol consistently decreased with increase in rpm after 8 h incubation and the maximum yield was observed at agitation speed of 100 rpm at 8 h incubation.

Keywords:

• ethanol
• fermentation
• extraction
• ethyl benzene
• agitation speed

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