Acidic Hydrolysis of Bread Waste for Bio-ethanol Production by Saccharomyces Cerevisiae

In-spite of large amounts production of bread waste annually, this waste is not suitable for food and animal feed applications due to aflatoxin contamination. In this study, bio-ethanol production from bread waste by Saccharomyces cerevisiae was investigated using acidic hydrolysis method. The acidic hydrolysis was performed by an autoclave apparatus. The effect of acidic solution concentration and time on amount of glucose was investigated. The experiments were carried out at loading of 160 g/l. Reduction of aflatoxin was measured for the sample with the greatest yield in acid hydrolysis. The sample obtained from hydrolysis was used for the production of bio-ethanol using Saccharomyces cerevisiae. The results showed that the effect of concentration of acid and time was significant at 1% level on the amount of glucose. Hydrolysis liberated the greatest amount of carbohydrate (80.64 g/l glucose) at the acidic solution concentration of 1% and time of 20 minutes. Also, acidic hydrolysis reduced aflatoxin B1 and B2 by 100% and 20.70%, respectively. The greatest percentage of bio-ethanol production in the fermentation phase of hydrolysis samples was 4.7 (v / v%).