Bioethanol Production From Banana Stem By Using Simultaneous Saccharification and Fermentation(SSF)

摘要

The rapid growth and development of industries in the world result in a greater energy needs.Some studies show that ethanol can be used as an alternative energy.However,bioethanol production from food raw materials such as sugar and starch has drawback that cause the food crisis.This aim of this study was to convert banana stem into bioethanol.Banana stem contained of 44.6% cellulose,36.0% hemicellulose and 19.4% lignin.After banana stems were pretreated with acid(H2S04)and alkaline(NaOH)at a concentration of 2% w/v at 121 °C for 30 minutes,then subsequently the simultaneous saccharification and fermentation(SSF)were carried out by using mixed cultures of Aspergillus niger,Trichoderma reesei and Zymomonas mobilis at various enzymes ratios of(1:1:1),(1:2:1),(1:2:2),(1:1:2)and various pH(4,5 and 6)with SSF time for 144 hours and temperature of 30°C.The results show that acid pretreatment showed better results than the alkali pretreatment.After acid pretreatment and alkali pretreatment,lignin content of pretreted banana stem reduced to 15.92% and 16.34%,respectively,cellulose increased to 52.11% and 50.6% respectively,hemicellulose reduced to 28.45% and 28.83%,respectively The SSF showed that pH 5 gave the highest bioethanol.The highest concentration of bioethanol(8.51 g IV)was achieved at the SSF process at pH 5 with a ratio Aspergillus niger,Trichoderma reesei and Zymomonas mobilis enzymes of(1:1:2).