Yeast S. cerevisiae is capable of rapid rate ethanol production
and glycolysis under optimum conditions [8]. The yield of alcohol in
fermentation process can be increased by optimizing the experimental
conditions. The use of factorial design for optimizing the fermentation
process is well documented [9-11]. Batch type of fermentation process
was employed because in continuous type, there is higher possibility
of mutation and contamination. In this work, anaerobic fermentation
was employed because during aerobic growth of S. cerevisiae, sugar
and ethanol can be used as carbon and energy source and growth
predominates over ethanol production. Under oxygen starvation
conditions, the fermentative metabolic pathway always predominates
[12]. Various factors affecting the fermentation process includes carbon
source, sugar concentration, dissolved oxygen level, agitation rate,