Green Extraction and Fractionation of Chestnut Wood Waste: A Sustainable Pathway to Biopolymers and Antimicrobial Solutions

The disposal of agri-food biomass waste, such as chestnut wood waste (CWW), poses significant environmental and industrial challenges, contributing to resource depletion and waste accumulation. The development of sustainable strategies for biomass valorization is crucial for reducing waste and promoting a circular economy. In this study, microwave-assisted subcritical water extraction (MASWE) is investigated as an efficient and environmentally friendly method for the extraction of high-value bioactive compounds such as condensed tannins (CTs), hydrolyzable tannins (HTs), and low-weight polyphenols from CWW. The extraction process is followed by sequential membrane filtration and resin purification, adhering to green extraction principles to maximize yield and avoid water wastage. Furthermore, tannins are utilized in the synthesis of biopolymers, offering a promising strategy for developing novel materials with tailored properties. Their antimicrobial activity and enzyme-inhibiting properties improve biopolymer formulations, unlocking diverse applications in sustainable materials. This approach through advanced extraction and fractionation protocols not only enhances biomass valorization—aligning with the circular economy in agri-food waste management—but also supports advancements in green technology and the development of eco-friendly materials.