Fungal Biotreatment of Agro-Industrial Wastes for the Production of Bioethanol in Bioreactor

BIOETHANOL production from lignocellulosic feedstocks is considered a promising strategy to increase global production of biofuels without impacting food supplies. This work aimed to evaluate bioethanol production by baker’s yeast using a medium containing the hydrolysate of fungal biotreatment of five different lignocellulosic feedstocks with some amendments. The pretreatment of lignocellulosic feedstocks using 5 % w/v NaOH, 1 % v/v H2SO4 and sodium hypochlorite: H2O2 (10:1) prior to fungal biotreatment was studied. For bioethanol production, batch, fed-batch (two strategies) and continuous cultivations of baker’s yeast on the fungal biotreated rice straw hydrolysate was evaluated in bioreactor. In batch and pulsed fed-batch cultivations, the highest bioethanol concentration, conversion coefficient, bioethanol yield and productivity were (0.41 % v/v, 36.9 % v/w, 36.9 % v/w and 0.114 ml/l/h, respectively), while in fed-batch cultivation with continuous feeding these parameters were (0.45 % v/v, 40 % v/w, 40.5 v/w % and 0.015 ml/l/h, respectively). The highest bioethanol concentration (0.52 % v/v) was obtained in continuous culture at dilution rate of 0.03 h-1, while conversion coefficient, yield and productivity were 31.2 % v/w, 31.4 % v/w and 0.022 ml/l/h, respectively