Efficient saccharification of Lycium barbarum leaf biomass by using enzyme cocktails produced by a novel fungus Aspergillus costaricensis LS18

The utilization of agro-industrial residues is an interesting issue contributing to sustainable development and environmental protection. Lycium barbarum leaves (LBL) are agro-industrial residues of the L. barabrum berry cultivation and seriously underutilized, leading to resource waste and environmental pollution. In this study, we prepared cost-effective enzyme cocktails with high xylanase activity from a novel soil-derived fungal strain Aspergillus costaricensis LS18. The xylanase activity of these on-site produced enzyme cocktails was 3.49 ± 0.55 U/mL. Through the hydrolysis using the enzyme cocktails with 6% substrate loading at 45 °C for 12 h, 86.57 ± 1.81% of total reducing sugars (RS) from LBL was released. The concentration of RS in the hydrolysates reached 8.17 ± 0.33 mg/mL. In this study, LBL were added values by two mutually independent bioprocess ways. On the one hand, LBL were used as the only nutrients in the medium for the on-site production of enzyme cocktails by fermentation. On the other hand, through hydrolysis using this enzyme cocktail, LBL biomass was efficiently hydrolyzed and fermentable monosugars were gained. This study could benefit to the exploitation of LBL resources and provide the references for utilization of other agro-industrial residues.