Optimization of microwave heated chemical pretreatment and simultaneous saccharification fermentation of banana pseudostem for ethanol production

Abstract

Ethanol is one of the most important renewable fuels, considered as a good alternative and additive for liquid transportation fuels with powerful economic and environmental attributes. In 2009, worldwide ethanol production was about 75.46 billion liters and the total projected demand in 2015 is over 115 billion liters. India is the largest producer of banana, contributing 27% of world s banana production. After harvesting the banana bunches from trees, 60 to 80 tons per hectare of waste biomass (banana pseudostem, leaves, etc) is generated in the field because each banana plant cannot be used for the next harvest. In this research work, banana pseudostems (BPS) were taken as the feedstock for the production of ethanol. Three chemical pretreatment techniques viz., lime (Ca(OH)2), sodium hydroxide (NaOH) and dil.sulfuric acid (H2SO4) were studied with microwave heating. A quadratic model was developed to correlate the response variable with the independent variables. To study the effect of microwave heating in the chemical pretreatment process, experiments were also performed using convection mode of heating. Experimental ethanol concentration by 24 h. Out of three chemical pretreatments considered in this research work, microwave heated lime pretreatment process gave the highest Experimental ethanol yield of 85%. It was also noticed that the increase in ethanol yield by using microwave was the highest of 18% in lime pretreatment process. Hence, microwave heated lime pretreatment process could be one of the best pretreatment processes for BPS. At the same time, power requirement and increase in capital costs are inevitable in microwave pretreatment method. However, the optimal pretreatment conditions need to be compromised with energy input and cost saving in large scale processing of BPS using microwave heated chemical pretreatment. newline newline newline