Abstract:
Increased energy demand of fuel oil (BBM) of the world have limited the availability of raw materials in the form of natural resources dwindling fossil fuels. The increase in energy demand over the years 2000 - 2009 an average of 7% per year. Based on data from the Directorate General of New Renewable Energy and Energy Conservation of the share of non-fossil energy <5%, in order to meet the fuel needs to be developed non-fossil fuels. One type of biofuel (BBN) is bioethanol. The raw material is potentially as sweet sorghum bioethanol (Sorghum bicolor L. Moench). Sorghum juice contains glucose levels from 10 to 14.40%. Bioethanol is the result of fermentation of carbohydrates with the help of microorganisms. In order to produce bioethanol plant scale, it is necessary to scale up the manufacture of bioethanol from sorghum juice through fermentation using Sacharomyces cereviceae biofermentor 10 000 ml size and alcohol concentration test using alkoholmeter. The purpose of this study was to determine the effect of volume and time starter fermentation to ethanol production levels, optimum fermentation conditions and growth kinetics of Saccharomyces cereviceae with volume variation starter (250 ml 500 ml and 750 ml) at each sampling time (6; 12; 24; 48; 72 and 96 hours). The fermentation process takes place in batches on the operating conditions of pH (4.0 to 5.0,) stirring speed of 200 rpm and at room temperature. 5000 ml juice fermented sorghum, with initial sugar concentration of 118.138 mg / ml as a fermentation medium is best demonstrated on the condition of the addition of 250 ml volume starter, fermentation time 72 hours with concentrations of ethanol produced 55.251 mg / ml, the ethanol yield of 91.702 g / ml with a final sugar concentration of 0.082 mg / ml, specific growth rate -0.0022 hour-1, petumbuhan maximum specific rate of 0.064 hr-1 and the substrate saturation constant of 0.024 gr / l.
