Kinetics of amyl alcohol production during ethanol fermentation of blackstrap molasses

Abstract

This paper reports results of studies on the effect of increasing amyl alcohol production on the kinetics and on the yield of ethanol fermentation with molasses as substrate. The production of amyl alcohols at concentrations of up to 1·0 g litre −1 did not affect the alcoholic fermentation. The amyl alcohol yields, calculated as a percentage of the theoretical production, were 66· 4% from l-leucine,57·3% from l-isoleucine, 55·7% from a mixture of l-leucine and l-isoleucine, and 36·1% from racemic leucine. Aeration did not affect the yield of amyl alcohols. When no amino acid was added to the mash, the kinetics of amyl alcohol production as well as the final amyl alcohol concentration depended mainly on the inoculum size. When 2·0 g litre −1 of l-leucine or of racemic leucine were added to the fermentation media, the initial stages of the kinetic patterns and the values of the maximum rate of amyl alcohol production were almost the same.