Engineering (electro)mixotrophy: production of bio-benign polymers from CO2-derived carbon feedstocks
EMSL Project ID
60209
Abstract
Plastics are an inevitable part of our everyday life. However, petroleum-based polymers come with a high environmental cost. Faced with climate change and environmental pollution, the need for bio-benign materials produced from renewable sources is becoming urgent. Despite the commitment, the transition from petroleum-based plastic to renewable alternatives is challenging. The industrial production of plastic using biological systems requires low-cost carbon feedstocks to compete with synthetic fossil-derived polymers. Electrosynthesis is becoming a commercially viable platform for producing simple reduced compounds, such as formate, acetate, and methanol. While many microbes can use these simple organics, the rates and efficiency of conversions are low. This application lies at the interface of electrosynthesis and biofermentation. We will address fundamental questions related to developing novel microbial traits for efficient conversion of mixed CO2-derived feedstocks into bio-benign plastics. Metabolic modeling coupled with flux balance analyses suggests that efficient carbon conversions (up to 70% carbon conversion efficiency) can be achieved via fine-tuning methanol, formate, and acetate metabolism. The conceptual framework of the proposed research activities is centered on experimental systems-level interrogations of mixed substrate utilization in wild- type and metabolically engineered microbial strains. Metabolic bottlenecks will be identified using a stable isotope tracing approach and non-targeted metabolomics. The data will be complemented by gene expression (RNA-seq) and protein biosynthesis (proteomic) data. The metabolic network landscape will be further evaluated via cryo-TEM analysis. Integration of novel knowledge into our current flux balance (FBA) model of C1 metabolism will represent a step toward predictable assessment of metabolic engineering strategies for further optimization of polyhydroxyalkanoate (PHA) production. The research outlined in this concept can lay the groundwork for developing a sustainable plastic market. PHAs can be substituted for the nearly 72.03 Million Tons of petroleum-derived polypropylene used for manufacturing fibers and molded materials. Microbial PHAs can be catalytically converted into propylene (market size of 29.2 Million Tons in the US) and used as fuel and energy carriers. Both the reduction of plastic pollution and innovative solutions for greenhouse gas (GHG) capturing are crucial elements of the US Department of Energy’s mission. Additionally, the established fundamental knowledge and computational framework for the model obligate methylotrophic culture will advance our understanding of C1-cycling in synthetic and natural systems. A refined vision of microbial co-metabolism and a better understanding of the interlinks between metabolic networks and mineral usage (i.e., copper and tungsten) will greatly improve environmental carbon-cycle modeling.
Project Details
Project type
Exploratory Research
Start Date
2021-12-01
End Date
2023-04-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)
Team Members