Two-step conversion of polyethylene into recombinant proteins using a microbial platform

Journal Article · 16 October 2023 · Microbial Cell Factories

DOI: https://doi.org/10.1186/s12934-023-02220-0 · OSTI ID:2202715

Connor, Alexander ^[1]; Lamb, Jessica V. ^[2]; Delferro, Massimiliano ^[2]; Koffas, Mattheos ^[1]; Zha, R. Helen ^[1]

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1. Rensselaer Polytechnic Inst., Troy, NY (United States)
2. Argonne National Laboratory (ANL), Argonne, IL (United States)

Background: The increasing prevalence of plastic waste combined with the inefficiencies of mechanical recycling has inspired interest in processes that can convert these waste streams into value-added biomaterials. To date, the microbial conversion of plastic substrates into biomaterials has been predominantly limited to polyhydroxyalkanoates production. Expanding the capabilities of these microbial conversion platforms to include a greater diversity of products generated from plastic waste streams can serve to promote the adoption of these technologies at a larger scale and encourage a more sustainable materials economy. Results: Herein, we report the development of a new strain of Pseudomonas bacteria capable of converting depolymerized polyethylene into high value bespoke recombinant protein products. Using hexadecane, a proxy for depolymerized polyethylene, as a sole carbon nutrient source, we optimized media compositions that facilitate robust biomass growth above 1 × 10⁹ cfu/ml, with results suggesting the benefits of lower hydrocarbon concentrations and the use of NH₄Cl as a nitrogen source. We genomically integrated recombinant genes for green fluorescent protein and spider dragline-inspired silk protein, and we showed their expression in Pseudomonas aeruginosa, reaching titers of approximately 10 mg/L when hexadecane was used as the sole carbon source. Lastly, we demonstrated that chemically depolymerized polyethylene, comprised of a mixture of branched and unbranched alkanes, could be converted into silk protein by Pseudomonas aeruginosa at titers of 11.3 ± 1.1 mg/L. Conclusion: This work demonstrates a microbial platform for the conversion of a both alkanes and plastic-derived substrates to recombinant, protein-based materials. The findings in this work can serve as a basis for future endeavors seeking to upcycle recalcitrant plastic wastes into value-added recombinant proteins.

• Research Organization: Ames Laboratory (AMES), Ames, IA (United States); Argonne National Laboratory (ANL), Argonne, IL (United States); Energy Frontier Research Centers (EFRC) (United States). Institute for Cooperative Upcycling of Plastics (iCOUP)
• Sponsoring Organization: National Science Foundation (NSF); USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-06CH11357; AC02-07CH11358
• OSTI ID: 2202715
• Journal Information: Microbial Cell Factories, Journal Name: Microbial Cell Factories Journal Issue: 1 Vol. 22; ISSN 1475-2859
• Publisher: BioMed CentralCopyright Statement
• Country of Publication: United States
• Language: English