Turning Carbon Into Bioplastics: Scientists Engineer Living Biofilms to Transform CO₂ Into Sustainable Materials

Imagine a world where carbon dioxide—one of the biggest culprits of climate change—is turned into eco-friendly, biodegradable plastics. Scientists have just made that reality a little closer with the development of a novel engineered living biofilm system that sustainably transforms CO₂ into polyhydroxyalkanoates (PHAs).

Led by a team at Tianjin University and collaborators across China and the UK, the study presents a first-of-its-kind two-layer biofilm architecture that uses photosynthetic cyanobacteria to fix CO₂ and E. coli to convert it into PHAs—a sustainable plastic alternative.

An engineered living biofilm system for sustainable conversion of CO2 into polyhydroxyalkanoates

How the System Works

The platform consists of two key layers:

Top layer: Photosynthetic Synechococcus elongatus fixes CO₂ via photosynthesis and secretes sucrose.
Bottom layer: E. coli consumes the sucrose and converts it into PHAs—a type of biodegradable plastic used in packaging, agriculture, and medicine.

This layered biofilm system is supported by a porous, reusable membrane scaffold, allowing for sustained biofilm growth, easy recovery, and long-term reuse (over 20 days without significant efficiency loss).

Key Innovations & Highlights

Direct CO₂ to plastic conversion via living biofilms
Engineered E. coli and S. elongatus co-culture for carbon-to-polymer conversion
Robust biofilm maintained on polyvinylidene fluoride (PVDF) membranes
Continuous PHB (a type of PHA) yield: up to 13.9 mg per cm² per day
Reusable system with minimal decline in productivity over multiple cycles

Why It Matters

Plastic pollution and climate change are two of humanity’s biggest environmental challenges. This research bridges both by:

Reducing atmospheric CO₂
Producing biodegradable, compostable plastics
Offering a low-energy, circular alternative to fossil-based polymers
Paving the way for carbon-neutral manufacturing platforms

Future Potential

Modular biofilm reactors for on-site CO₂ utilization
Integration into waste gas recycling in factories
Sustainable manufacturing for packaging and medical materials
Solar-driven CO₂ capture using light-powered cyanobacteria

Reference

Wang, W., Zhang, W., Chu, F., Xiao, T., Hu, D., Tang, P., … & Ge, H. (2025). An engineered living biofilm system for sustainable conversion of CO2 into polyhydroxyalkanoates. Cell Reports Physical Science. DOI: 10.1016/j.xcrp.2025.10267