Production of ethanol from agro-industrial wastes: i. pretreatment of raw materials for using in fermentation processing

This study aimed to utilize of the agro-industrial wastes as a cheap materials for the production raw material for using in fermentation processing, at the same time eliminates environmental impact of open burning of waste. conditions for acid hydrolysis of waste, to produce hydrolysate containing invert sugar were study. in this respect, milled rice straw, cotton stalks and beet pulp were subjected to pretreatment using diluted acid solution at high temperature to enable production of the maximum amount of fermentable sugars from acid hydrolysis. the effects of various operating variables including pretreatment temperature, pretreatment time of reaction, the concentration of acid, the solid-to-liquid ratio and soaking time on the degree of lignin removal and liberation of reducing sugar. acid pretreatment was carried out with h2so4 at 1–5% (w/v) concentrations at 121°c and solid: liquid ratio ranged from 1:5 to 1:25(w/v) for time ranging from 20 to 120 min. the results reveal that, there was a significant differences among the three by- products. the optimal reaction conditions, which resulted in an acid hydrolysis, were (1:20) (w/v) solid to liquid ratio; 121˚c hydrolysis temperature; 4% (w/v) acid concentration, 90min reaction time and pre-soaked for 36 hours.