P81: Effect Of Agitational Intensity, Temperature and Initial Cell Concentration On The Ethanol Production By A Flocculent Yeast Using Cashew Apple Juice As Carbon Source

Environmental factors such as inoculum type, pH, temperature, substrate aeration and agitation affecting fermentation. An important parameter to study in bioreactor studies is a mechanical mixing. Greater agitation produces more dispersion hence the greater mass transfer rate. The influence of temperature on the kinetic parameters must be considered, because the process is exothermic, affecting direct the process fermentation. The initial cell concentrations influence directly the productivity and yield. The purpose of this study was to investigate the growth kinetics of S. cerevisiae flocculent CCA008 and ethanol production at different agitation rates, temperature and initial cell concentrations. Batch fermentation with agitation rate 80 – 800 rpm was studied at 30 °C and using 5 g.L-1 of initial cell concentration using cashew apple juice a medium containing 100 g.L-1 glucose and fructose carbon source. The results indicate that agitation was a significant factor to improve ethanol concentration and yield. The initial cell concentrations used in fermentations varies from 3 to 10 g.L-1. A high initial cell concentration increases the rate ethanol formation and the ethanol productivity. However, the yield of fermentative process has not been documented. Experiments were performed at temperature range from 26 to 42°C and the kinetic parameters were described as functions of temperature. The higher ethanol production was obtained in the experiments conducted at 34 °C and 80-490 rpm using 5 g.L-1 initial cell concentration.