Recovery of melon residues (Cucumis melo) to produce lignocellulolytic enzymes

Abstract

Lignocellulosic biomass is considered the raw material of the future to produce ethanol, due to its low cost and its enormous availability. Lignocellulosic enzymes play a crucial role in the costs and sustainability of biorefining processes by promoting the biomass fractionation. In this study, the melon waste was used as inducer source to produce lignocellulolytic enzymes by Aspergillus niger M4 strain under submerged fermentation (SmF). The chemical characterization of the whole fruit showed a high content of sugars, as well as hemicellulose, followed by lignin and cellulose. The dried and crushed melon was used as a substrate in submerged fermentation, to induce the synthesis of lignocellulosic enzymes. The Aspergillus niger M4 strain was able to grow and synthesize lignocellulose degrading enzymes, allowing free-glucose values of 3.7 g/L. The culture broth showed endo-glucanase activity (1.21 U/mL), xylanase activity (11.00 U/mL), and laccase activity (18.23 U/mL). The entire melon (Cucumis melo L.) wastes can be used as a substrate in the lignocellulosic enzyme production by submerged fermentation process for further application in the biomass pretreatment for bioethanol production.