Environmental Sustainability of Chitin and Chitosan Extraction: What Current Sustainability Assessments Reveal for Insect Biomass Valorisation

Chitin and chitosan are valuable biopolymers that are currently produced mainly from crustacean processing residues. In recent years, interest in alternative biomass sources, particularly insects and fungi, has increased as part of broader bioeconomy and biomass valorization strategies. However, the sustainability of chitin and chitosan production depends not only on the feedstock used but also on the extraction process employed. This study presents a systematic literature review of sustainability assessments related to chitin and chitosan extraction from crustacean, fungal, insect and mollusk biomass sources. A total of 26 studies were identified and analyzed with respect to assessment methods, environmental hotspots, emerging extraction technologies and research gaps. Life cycle assessment was the most frequently applied sustainability assessment approach. Energy consumption and chemical use were the environmental hotspots most frequently reported across the reviewed literature. While several studies compared conventional and alternative extraction routes, environmental performance was highly dependent on process-specific factors. Notably, no sustainability assessment of insect-derived chitin extraction or subsequent chitosan production was identified. The findings highlight the current state of sustainability assessment in the sector and identify priorities for future research.