Fungal pretreatment of sugarcane bagasse: a green pathway to improve saccharification and ethanol production

Biological pretreatment was investigated to increase ethanol production from lignocellulosic biomass, like sugarcane bagasse. Enzyme secretion, changes in substrate composition, enzymatic hydrolysis, and ethanol yield after pretreatment by different basidiomycetes were evaluated. Analysis by Fourier transform infrared spectroscopy showed that Pleurotus pulmonarius PS2001 and Trametes villosa 82I6 promoted more extensive selective modifications in the lignin content. Glucose release during enzymatic hydrolysis of samples pretreated with P. pulmonarius PS2001 for 35, 42, and 49 days and with T. villosa 82I6 for 21, 28, and 49 days were higher than the control (48.5 +/- 2.38 mg/g), i.e., 68.4 +/- 0.7, 76.3 +/- 1.6, and 76.5 +/- 2.1 mg/g and 70.9 +/- 8.3, 77.8 +/- 5.8, and 77.6 +/- 4.2 mg/g, respectively. During the fermentation of hydrolysates of samples pretreated with T. villosa 82I6 for 14, 28, and 49 days, a maximum ethanol yield of 17.8 +/- 1.9, 19.1 +/- 2.8, and 20.2 +/- 0.5 mg/g, respectively, was achieved. A positive effect of biological pretreatment on hydrolysis and fermentation was demonstrated.