Biochemical Depolymerization
The breakdown of synthetic or natural polymers using specialized proteins allows the recovery of high-purity monomer units. In the textile industry, enzymatic recycling targets polyester or nylon blends to isolate their chemical building blocks. This process operates at lower temperatures than conventional thermochemical recycling.
It enables the circular processing of mixed-fibre garments.
Selectivity Factor
Specific enzymes target only one polymer type in a mixed-fabric stream, leaving other materials untouched. For example, polyester-digesting enzymes can break down polyethylene terephthalate in a cotton-polyester blend, allowing the cotton fibres to be recovered intact. This selective reaction avoids the heavy chemical treatments that damage secondary fibres.
The recovered monomers can then be repolymerized into virgin-grade synthetic fibres that match the performance of fossil-based polyester.
Reaction Rate
The rate of polymer breakdown depends on the surface area and crystallinity of the starting textile waste. Grinding the fabric into fine powder increases the access of enzymes to the polymer chains, accelerating the depolymerization process. This step requires mechanical energy but reduces the reaction time from days to hours.
Optimized reaction conditions are essential for commercial viability.
Process Limitation
Dyes and chemical finishes on the input fabrics can inhibit enzyme activity. These contaminants must be removed through a pre-treatment wash to ensure full enzymatic efficiency. This adds to the overall process cost.
