Optimization of Solid State Fermentation for Reducing Sugar Production from Agricultural Residues of Sweet Sorghum by Trichoderma harzianum

Sweet sorghum is an attractive feedstock for ethanol production. The juice extracted from the fresh stem contains sucrose, glucose, and fructose and can be readily fermented to alcohol. The solid fraction residue, the so-called bagasse, is a lignocellulose which can further be processed to ethanol. In this work, optimal conditions for reducing sugar production from sweet sorghum bagasse under Solid State Fermentation (SSF) by Trichoderma harzianum was investigated. Response Surface Methodology (RSM) using Box-Behnken Design (BBD) for optimization of culture conditions was performed; these parameters were initial moisture content, inoculum size and incubation time. The reducing sugar production from sweet sorghum bagasse by means of SSF was achieved after sequential of acid and alkaline pretreatments. The experimental data showed that the highest value of reducing sugar from cellulose pulp were produced at initial moisture content of 77.5%, inoculum size as 10.5% and 56 hours of incubated time. Under these conditions, reducing sugar of 10.34% (g/g dry materials) was obtained.