Given the important effect of the sugarcane bagasse particle size, additional experiments using intermediate (0.5 ≤dp ≤ 1.0 mm) and larger (2.0 ≤dp ≤ 2.4 mm) particle size ranges were carried out in order to further investigate the effect of this variable, as presented in Fig. 1.
For this set of experiments using shake flask cultivations, it could be concluded that sugarcane bagasse particle sizes smaller than 0.5 mm hindered fungal growth, while increase in particle size up to 2 mm showed a positive effect on endoglucanase production. These results can be explained by the fact that although small particle sizes increase the substrate surface area, hence increasing the interaction between the filamentous fungus and the inducer substrate, reduced particle size can also result in agglomeration of the solid substrate, with consequent oxygen limitation restricting fungal growth [13], [31] and [32].