In addition to the good performance of the filamentous fungus P. funiculosum cellulase blend on sugar cane bagasse cellulignin (high stability, well balanced endoglucanase–exo glucanase and β-glucosidase activities, high glucose concentration during pre-enzymatic hydrolysis), the high ethanol concentration achieved in this study (100 g/L), during the simultaneous saccharification and fermentation, by an industrial strain of S. cerevisiae point to a possible use of this enzymatic product for the production of second generation ethanol at a productive scale.
Considering the experimental results herein obtained, involving the cellulase production, the use of the enzymatic blend in the simultaneous saccharification and fermentation for second generation ethanol production (only from the cellulose fraction), it was possible to do some estimates: an amount of 210 kg of sugar cane bagasse PDC is necessary for producing sufficient cellulase (12.5 × 106 FPU) to hydrolyse one ton of sugar cane bagasse PDC being intended for second generation ethanol production. Also, for a total solid concentration (PDC) of 33.3% w/v, an ethanol concentration of 100 g/L was obtained, which leads to the ratio of 380 L of ethanol/ton of sugar cane PDC.
When the ethanol production is evaluated taking into account the whole sugar cane bagasse, which yielded 350 kg of PDC, a ratio of 135 L/ton is attained. However, not considering enzyme recycling or immobilization, 17% of PDC should be used for enzyme production and the remaining 83% for ethanol production. Thus, in the experimental conditions used in the present work, 110 L of ethanol is estimated to be produced from each ton of sugar cane bagasse, considering only the cellulose component. Finally, thinking over the SSF process, the fermentation efficiency was 78% of the maximum obtainable theoretically.