Canola meal as a promising source of fermentable sugars: Potential of the Penicillium glabrum crude extract for biomass hydrolysis

Abstract

Recent studies have revealed that canola meal is much more than only a by-product from oil extraction. However, studies that evaluate its use as feedstock in the processes of ethanol production are scarce. This work aimed to address the use of canola ( Brassica campestris ) meal as potential raw material for bioethanol production. Initially, the optimal conditions for the production of β-glucosidases by a Penicillium glabrum strain were established, using canola meal as a substrate. To this end, the Central Composite Rotational Design (CCRD) applicable to the Response Surface Methodology (RSM) was used. These same statistical tools were used in order to establish the best hydrolysis conditions of the chemically pretreated canola meal using the P. glabrum crude extract, whose β-glucosidases were biochemically characterized. As a result, the maximum level of β-glucosidases production (22.45 ± 1.04 U mL −1 ) was reached when the fungus was grown for 6.5 days, at pH adjusted to 6.0, using a substrate concentration of 2%. The enzymes were more active at 70 °C, pH 4.0, remaining stable at 65 °C and over a broad pH range. The highest levels of glucose (34.54 mg g −1 substrate) were obtained when the hydrolysis process was conducted at 65 °C, pH 4.0, for 75 h, using an enzyme concentration corresponding to 13.75 U g −1 dry feedstock. From the results, it can be concluded that canola meal is a promising raw material, both for the production of low-cost β-glucosidases and for obtaining fermentable sugars, aiming at the production of bioethanol. • The β-glucosidase production using canola meal as substrate is reported. • An efficient approach for enzymatic hydrolysis of canola meal was established. • P. glabrum crude extract was able to efficiently hydrolyze the canola meal. • Substantial yields of glucose were achieved.