Determination of yeast co-culture ratio and stirring for optimization of bioethanol content of garlic (Allium sativum) peels and corn (Zea mays L.) cob

Abstract

Bioethanol as a source of energy from biomass of garlic peels and corn (Zea mays L.) cobs waste come into one alternative to reduce the dependence of fossil fuels and the increasingly severe environmental damage. The aims at the research were bioethanol producing with optimum level of garlic (Allium sativum) peels and corn cob revealed from yeast co culture and stirring ratio and interaction between both. Fermentation performed during 3 days with various yeast co culture of yeast tape and bread yeast with stirring ratio and control (without stirring). Data analyzed on each type of waste source by design of factorial treatment (4 × 2) and Randomized Block Design (RBD ) with 4 repetitions. As the first factor is the ratio of yeast tape co-culture and bread yeast consisting of 4 levels, that is 7.5%:7.5%; 10%:5%; 15%:5% and 20%:5%. A second factor is done stirring and without stirring. Comparison of the ethanol production percentage performed between the raw materials source. The research can be concluded that the most optimal of ethanol content of garlic peels are 7.428 ± 0.072% on interaction ratio of tape yeast 15% and bread yeast 5% with stirring. The most optimum ethanol product of corn cobs is 8.19% produced at ratio of 10% yeast tape and 5% yeast bread with stirring.