(425b) Economic and Environmental Analysis of Polyhydroxyalkanoates (PHA) Production Using Plasma-Biological Hybrid Process

Polyhydroxyalkanoates (PHA) are a family of biodegradable plastics derived from several types of microbes. PHA is an environmentally friendly alternative to conventional fossil-based plastics because of its biodegradability, thermoplastic, and mechanical properties [1]. PHA has a well-established market with several applications in packaging, food containers, clothing, medical implants, etc. The PHA market was valued at $650.6 million in 2023 and is expected to grow at a compound annual growth rate (CAGR) of 9.35% in the coming 5 years [2]. One of the significant barriers to the market expansion of PHA is its high production cost. Conventional petrochemical-based plastic costs $1 to $1.5/kg, while PHA varies from $4kg to $15/kg [1]. Feedstock cost is one of the main contributors and accounts for 30-50% of the PHA production cost [3], [4]. Therefore, research is being conducted to develop bioconversion processes that utilize waste streams, such as food waste, municipal solid waste, and agricultural waste, for PHA production.

In this study, an industrial-scale PHA production system was designed, and both techno-economic and life cycle analyses were conducted to evaluate its profitability and environmental impact. In this process, we showed that plastic waste can be an inexpensive carbon source for the synthesis of PHA. The system consists of a plasma-biological hybrid technology, in which the plastic waste is deconstructed into an oxygenated liquid product (OIL) using a plasma-CO₂ activated reactor, and the plasma oil is used to synthesize PHA through microbial fermentation. The process was modeled using experimental data obtained at the laboratory scale. The process simulation, material and energy balance, and TEA analysis were conducted with the open-source platform BioSteam 2.38.6, and the LCA was performed in OpenLCA 1.11.0 and the Ecoinvent database.

The conceptual facility is designed to process 200 metric tons of waste polyethylene (PE) per day. The material balance indicated an annual production of 12,400 tons of PHA and 18,315 tons of lubricants as byproducts. The TEA revealed a minimum selling price of $0.88/kg for PHA, making it more cost-competitive than other bioplastics and petroleum-based plastics. The total installed cost of the plant is estimated at $86 million, with a net present value (NPV) of $413 million, demonstrating the economic viability and high revenue potential of PHA production from plastic waste. Additionally, the life cycle emissions of the process were calculated at 1.67 kg CO₂e per kg of PHA. Sensitivity analysis highlighted that cell PHA content and PHA price are critical factors influencing the plant’s profitability.

The findings of this study indicate that using plastic waste as a feedstock to produce PHA can lower its production cost and make it more competitive in the bioplastic market. The plasma-hybrid technology not only mitigates plastic waste pollution but also enables cost-effective bioplastic production with a lower environmental footprint. For future work, we will conduct a supply chain analysis to determine suitable locations in the United States for deploying the facilities.

References

[1] B. Yadav, A. Pandey, L. R. Kumar, and R. D. Tyagi, “Bioconversion of waste (water)/residues to bioplastics- A circular bioeconomy approach,” Bioresource Technology, vol. 298, p. 122584, Feb. 2020, doi: 10.1016/j.biortech.2019.122584.

[2] “Polyhydroxyalkanoates Market Size & Share Report, 2030.” Accessed: Apr. 01, 2025. [Online]. Available: https://www.grandviewresearch.com/industry-analysis/pha-polyhydroxyalka…

[3] K. Wang, A. M. Hobby, Y. Chen, A. Chio, B. M. Jenkins, and R. Zhang, “Techno-Economic Analysis on an Industrial-Scale Production System of Polyhydroxyalkanoates (PHA) from Cheese By-Products by Halophiles,” Processes, vol. 10, no. 1, p. 17, Dec. 2021, doi: 10.3390/pr10010017.

[4] R. Fu, L. Kang, C. Zhang, and Q. Fei, “Application and progress of techno-economic analysis and life cycle assessment in biomanufacturing of fuels and chemicals,” Green Chemical Engineering, vol. 4, no. 2, pp. 189–198, Jun. 2023, doi: 10.1016/j.gce.2022.09.002.