Biocatalytic recycling of biodegradable films using greater wax moth larvae and gut microbiome enzymes

Overview

This research program develops a nature-inspired biocatalytic recycling pathway for mixed biodegradable food packaging films, including polylactic acid (PLA) and polyhydroxyalkanoate (PHA). The approach exploits the evolutionary adaptation of greater wax moth (Galleria mellonella) larvae, which naturally digest beeswax—a material structurally similar to aliphatic polyesters. Initial proof-of-concept work has demonstrated that larvae can consume mixed PLA/PHA films as their sole food source, complete their lifecycle, and produce frass containing digested polymer. The program will identify the enzymes and microbial species responsible for this breakdown, then translate those biological catalysts into engineered enzymatic and synthetic biology recycling technologies capable of converting used biodegradable films back into valuable starting materials such as lactic acid monomers.

Technical specifications

• Larval digestion model: Greater wax moth larvae (n=13) successfully consumed mixed PLA and PHA packaging films without requiring prior film separation or contaminant removal, and completed pupation on this diet.
• Metaproteomic analysis: Whole-cell and gut lysates from larvae fed biodegradable films for four days will be analysed at the Australian Proteomics Facility (co-located at Macquarie University) to identify enzymes enriched during polymer digestion, compared against larvae on a standard control diet.
• Gut microbiome isolation: Native microbial species from the Galleria gut will be enriched by culturing in media containing sheared biodegradable film as the sole carbon source, enabling isolation of polymer-degrading consortia.
• Breakdown characterisation: Polymer degradation by-products will be tracked over time using gas chromatography–mass spectrometry (GC-MS) and gel permeation chromatography to confirm full polymer cleavage and identify monomer recovery.
• Translation pathway: Identified enzymes and microbial pathways will be engineered into standalone enzymatic processes and synthetic biology platforms for industrial-scale recycling of biodegradable films.

Technology readiness level

The project is at an early proof-of-concept stage (TRL 2–3). Preliminary validation has confirmed that Galleria mellonella larvae can digest mixed PLA/PHA films and complete their lifecycle on this diet, demonstrating biological feasibility. The next six-month phase will generate the first POC dataset characterising the responsible enzymes, microbial species, and breakdown products. Following successful POC, a subsequent partnership phase will develop prototype enzymatic and synthetic biology recycling solutions. The research builds on the team's prior published and unpublished work characterising enzymatic pathways for thermoplastic polyurethane biodegradation, providing a validated methodological pipeline for this expanded application.