Saccharification of different sugarcane bagasse varieties by enzymatic cocktails produced by Mycothermus thermophilus and Trichoderma reesei RP698 cultures in agro-industrial residues

Abstract

Lignocellulosic biomasses are promising sources for the obtaining of clean energy through their bioconversion into ethanol. Their saccharification involves a multi-enzymatic system. Here, we evaluated the hydrolysis of a mixture of sugarcane bagasse varieties (SCB), Energy cane fiber (EC), and sugarcane bagasse from the SP80-3280 variety, all in natura, using fungal enzymatic extracts obtained from Mycothermus thermophilus and Trichoderma reesei RP698 cultures supplemented with various agro-industrial residues. The enzymatic extracts from both fungi, when grown in a corn cob and corn straw, led to the highest sugarcane hydrolysis. For M. thermophilus, the reducing sugars released (mg/mL) were 1.21 ± 0.12, 1.25 ± 0.14, and 0.98 ± 0.05 for SCB, EC and SP80-3280, respectively; for T. reesei, the reducing sugars were 0.84 ± 0.08, 0.89 ± 0.06 and 0.68 ± 0.03 for SCB, SP80-3280, and EC, respectively. The cocktail obtained from the co-cultivation of these fungi in corn straw at 35 °C showed the best hydrolysis results, the release of sugars (mg/mL) was 1.31 ± 0.06 (SCB), 2.18 ± 0.08 (EC) and 1.67 ± 0.09 (SP80-3280). Scanning electron microscopy and thermogravimetric analysis confirmed changes in the fiber structures after enzymatic hydrolysis. Thus, these fungi were shown to be promising for an enzymatic cocktail design and sugarcane biomass saccharification.