ABSTRACT

A three-variable Box-Behnken design (BBD) was employed to model, optimize and evaluate the effect of fermentation time, amount of biomass and hydrolysis time on percentage yield of bioethanol produced from cassava peels. Collection and preparation of the cassava peels was done, pretreatment was carried out by soaking and autoclaving at 100°C for 1 hour with NaOH. Acid hydrolysis was carried out on the pretreated substrate by varying amount of biomass (20 to 60g), hydrolysis time (30-60 min) using 20M conc. H₂SO₄ with 98% purity and fermentation was carried out using Saccharomyces cerevisiae at varied fermenttation time between (2-5 days). Statistical analysis of the results showed that all the factors had significant effect on the responses. Quadratic models were developed for percentage yield of bioethanol from cassava peels. The model was significant with p< 0.0001 and showed good fit to the experimental data. The production of bioethanol from cassava peels was positively influenced by fermentation time, amount of biomass and hydrolysis time. The optimum conditions for ethanol yield was 7.82205% at a fermentation time of 5 days, amount of biomass of 58.90 g and hydrolysis time of 42.84 min. Validation of the model indicated no significant difference between the predicted and the experimental values.