Biological recycling and upcycling of phas into high-value chemicals and materials

Overview

Ourobio is developing a recycling and upcycling platform for polyhydroxyalkanoates (PHAs), a family of biodegradable bioplastics produced through microbial fermentation. The technology uses a combination of chemical and enzymatic depolymerization to break down PHAs into crotonic acid, a valuable platform chemical with an existing market exceeding $500 million. Crotonic acid can be reintroduced into fermentation to regenerate new PHA, or used as a building block for copolymers used in paints, lacquers, and adhesives, as well as larger molecules for medicines and hydrogels. The process also applies to composites of PHA and other biopolymers such as PLA, enabling separation and recovery from mixed recycling streams. This approach transforms end-of-life PHA materials from a disposal challenge into a source of high-value chemicals, supporting circular economy objectives for brands and materials manufacturers.

Technical specifications

• Combined chemical and enzymatic depolymerization: A two-step process starting with enzymatic degradation using PHA depolymerase enzymes from various microorganisms, followed by chemical degradation to maximize conversion efficiency.
• Target output: Crotonic acid with projected yield and purity exceeding 99%, validated through distillation and Liquid Chromatography-Mass Spectroscopy analysis.
• Process optimization: Evaluation of pressure, temperature, and pH parameters to optimize chemical depolymerization conditions.
• Enzyme development: Expression and purification of PHA depolymerases from multiple microbial sources to assess in vitro depolymerization performance.
• Composite handling: Capability to process mixed-material streams, specifically PHA-PLA composites, enabling separation of PHA from blended biopolymers.
• Crotonic acid applications: Re-fermentation to produce new PHA, synthesis of copolymers for coatings and adhesives, and use as a precursor for pharmaceutical compounds and hydrogels.
• Energy efficiency: Chemical depolymerization methods are expected to require similar energy inputs to de novo PHA production, based on prior published studies.

Technology readiness level

Chemical depolymerization of PHA into crotonic acid has been validated at the laboratory scale in published studies. However, larger-scale deployment has been limited by the absence of widespread PHA collection and use in everyday products. Enzymatic depolymerization using PHA depolymerases remains underexplored, representing an opportunity to improve yields and purity beyond what chemical methods alone can achieve. The proposed research plan aims to validate the combined chemical-enzymatic approach at laboratory scale, optimize process parameters, and demonstrate feasibility on composite materials. Ourobio brings established expertise in PHA synthesis, extraction, and processing, as well as capabilities in protein engineering and purification, and an established distribution network within the biopolymer industry to support continued development toward commercial readiness.