Project Spotlight. Bioplastics

Secretion of Bioplastics Produced in E. coli is Novel in Downstream Processing

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More than 60 billion pounds of plastic materials are thrown away each year in the United States. These traditional plastics are derived from non-renewable resources and are not biodegradable.

Polyhydroxyalkanoates (PHAs) comprise a class of polyesters that are generated by a variety of microorganisms. These bioplastic compounds are intracellularly accumulated and stored as a reserve of carbon, energy, and reducing power in response to an environmental stress or nutrient limitation. PHAs have comparable material properties to conventional plastics, like polypropylene, but are fully biodegradable and renewable. As a result, PHAs are of particular interest as a sustainable source of non-petrochemically derived thermoplastics for use in an assortment of commercial and medical applications.

Traditional PHA downstream processing methods involving the use of solvents, enzymatic digestion, or mechanical disruption are expensive and impractical for industrial-scale production. Charles Miller, an affiliate member of the Synthetic Bioproducts Center at USU, is investigating how to reduce some of the costs associated with bioplastic production.

Miller creates PHAs using E. coli bacteria as the production platform. His research team has created E. coli that have been biologically engineered to secrete bioplastic material, thus simplifying downstream processing methods.

Associated Faculty


Miller creates PHAs using E. coli bacteria as the production platform. His research team has created E. coli that have been biologically engineered to secrete bioplastic material, thus simplifying downstream processing methods. His research group is also investigating the utilization of a broad range of waste and surplus materials that can be upgraded to the role of feedstocks for production of PHB to reduce the overall costs associated with microbial bioplastic production. The use of renewable waste streams for production of PHB will not only increase the economics, but also provides a strategy to overcome disposal problems for industries. Thus, the long-term goal of this research is to develop a PHB production system that ultimately makes biodegradable bioplastics from renewable resources a competitive alternative to petrochemically derived plastics.

Miller’s research specialties include cellular engineering, synthetic biological engineering, bioplastics and biofuel production using biological engineering methods.

Related Publications

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Sathish A, Glaittli K., Rahman A, R Sims, RC and Miller CD. 2013. Production of poly(3-hydroxybutyrate) (PHB) from recombinant Escherichia coli grown using an algae based media generated from a wet lipid extraction procedure. Third International Conference on Algal Biomass, Biofuels and Bioproducts. Toronto, Canada

Osei E, Rahman A, and Miller CD. 2012. The impact of bioplastic secretion of cell viability. 17th Annual Institute of Biological Engineering conference, Indianapolis, IN (1st place award)

Rahman, A, Sims, R.C., and Miller, C.D. 2012. Polyhydroxyalkanoate production from Escherichia coli: carbon sources and scale up. 17th Annual Institute of Biological Engineering conference, Indianapolis, IN