Abstract
The aim of this paper is to describe simple optimization problems of aerobic batch ethanol fermentation by yeast organisms (Saccharomyces cerevisiae) and to give a planning map for ethanol production.
The initial concentrations of glucose and of cell mass were considered to be decision variables, yield of ethanol for glucose and amount of ethanol produced were assumed to be the performance criteria of importance. The parameters, related to the physiological properties of the cells, which are necessary to optimize the performance criteria were elucidated. Calculations and experiments showed that one optimum performance point occurs when ethanol yield for glucose reaches its maximum value of 46% and amount of ethanol produced is 92 mg/ml; this occurred under the condition where the initial concentration of cell mass was 1.9 mg/ml and that of glucose was 200 mg/ml. Another optimum performance point was obtained with initial concentrations of cell mass and of glucose 2.0 mg/ml and 140 mg/ml, respectively, which gave a minimum fermentation time of 11 hours and a maximum ethanol yield of 46%.
