WG1 identifies high-potential food waste streams as raw materials for fiber extraction and evaluates their technical, environmental, and economic feasibility for industrial-scale applications. By building and maintaining a comprehensive fiber-source database, conducting feasibility analyses, and collaborating with industry stakeholders, WG1 ensures that the Action begins with sustainable, abundant, and commercially viable raw materials. This foundational work supports all downstream WGs, enabling efficient extraction, accurate characterization, and successful product development.