Maximizing fermentable feedstocks from Camellia oleifera seed oil extraction residues: Green pretreatment and enzymatic hydrolysis for effective valorization

This study aimed to convert wastes generated during the extraction of oil from Camellia oleifera seeds, including the fruit shell (COFS) and seed cake (COSC), into fermentable feedstocks using pretreatment and enzymatic hydrolysis processes. The application of a green acid catalyst in the thermochemical pretreatment of the COFS and COSC mixture yielded the highest sugar of 28 g/L. Solid-state fermentation (SSF) was conducted on-site using various waste biomass substrates to produce enzymes for the saccharification process. This study found that COFS was the ideal substrate for generating SSF enzymes capable of breaking down lignocellulosic biomass. A novel enzymatic hydrolysis strategy was developed to minimize water consumption and enhance substrate utilization efficiency. By fine-tuning the enzymatic hydrolysis process, an additional sugar of 20.58 g/L was achieved using thermochemically pretreated solid residues and SSF enzymes. Standard techniques were used to analyze the raw materials, residual solids, and hydrolysates to assess the efficiency of each processing step. In general, the use of SSF enzymes and green pretreatment methods, reduction of water consumption in the process, and implementation of an efficient biomass utilization approach, enhance the overall efficiency and eco-friendliness of this study.