How Nottingham's Bacteria Banquet Turns Pollution into Products
In a world drowning in carbon waste, synthetic biologists serve up a revolutionary recipe: bacteria that devour greenhouse gases and excrete valuable chemicals.
Every year, industries belch 8 billion tons of carbon monoxide (CO) and carbon dioxide (CO₂) into our atmosphere—gases that accelerate climate change while representing wasted chemical potential. At the University of Nottingham's Synthetic Biology Research Centre (SBRC), scientists are flipping this problem on its head. They engineer bacteria to feast on these C1 waste gases, transforming pollutants into platform chemicals for plastics, fuels, and medicines. Established in 2014 as one of the UK's first synthetic biology hubs, SBRC-Nottingham pioneers a future where industrial emissions become raw materials, breaking our fossil fuel addiction 1 4 .
Oxygen-hating microbes that thrive on syngas (a mix of CO/CO₂/H₂) from steel mills or biomass gasification. Using the ancient Wood-Ljungdahl Pathway, they stitch C1 gases into acetyl-CoA—a molecular building block for chemicals 6 .
| Chemical | Uses | Production Host | Extraction Advantage |
|---|---|---|---|
| Ethylene | Plastics, antifreeze | C. necator | Volatile—easily evaporated |
| Isobutene | Synthetic rubber, jet fuels | C. necator | Gas-phase recovery |
| 3-Hydroxypropionic acid | Acrylates, adhesives | Clostridia | Water-soluble separation |
| Butadiene | Tires, nylon polymers | Both | Low boiling point |
The centre's success stems from its "roadmap to gene system development"—a suite of patented genetic tools:
A gene-knockout system using retargeted group II introns, enabling precise disruption of genes in clostridia 1 .
Gene insertion/deletion enabling complex pathway engineering.
| Tool | Function | Impact |
|---|---|---|
| ACE (Allele Coupled Exchange) | Gene insertion/deletion | Enabled complex pathway engineering |
| CodA Selectable Marker | Counterselection for mutants | Accelerated strain optimization |
| TraDis Transposon | Random gene insertion | Allowed high-throughput gene screening |
| CRISPRi in C. necator | Multiplex gene repression | Silenced PHB storage, boosted product secretion 9 |
Wild Clostridium autoethanogenum naturally produces acetate and ethanol but at inefficient ratios. SBRC researchers aimed to "flip" metabolic flux toward ethanol—a valuable biofuel 6 .
| Strain | Ethanol Yield (g/L) | Acetate Yield (g/L) | Carbon Efficiency |
|---|---|---|---|
| Wild Type | 1.2 | 5.8 | 28% |
| ΔadhE mutant | 0.05 | 9.1 | 15% |
| AOR+ADH strain | 3.5 | 1.2 | 75% |
The synthetic pathway boosted ethanol yield 180% while slashing acetate waste. This proved modular pathway engineering could override native metabolism, unlocking high-yield gas fermentation for industry 6 .
| Reagent/Equipment | Function | Example in Use |
|---|---|---|
| RoboLector® | Automated micro-fermentation system | Screened 96 C. necator mutants in parallel for isobutene production |
| pMTL70000 Vectors | Plasmid series for Cupriavidus engineering | Expressed isoprene synthase in C. necator 1 |
| 13C Metabolic Flux Analysis | Tracks carbon atoms in pathways | Mapped COâ‚‚ fixation routes in PHB-deficient mutants 9 |
| Gas-Enabled CSTRs | Continuous stirred-tank reactors | Scaled Clostridium fermentation to 100L with real-time gas monitoring |
| Raman Spectroscopy | Non-invasive metabolic profiling | Detected intracellular 3-hydroxypropionic acid accumulation |
The centre's Doctoral Training Programme bridges biology/engineering, with projects like "Synthetic Calvin Cycle for Efficient COâ‚‚ Fixation" 9 .
Outreach initiatives include school "microbiology dances" explaining gas fermentation and YouTube series demystifying synthetic biology (47,500+ views) 2 .
SBRC-Nottingham envisions integrated "electromicrobial bioreactors" where bacteria convert CO₂ from direct air capture into chemicals—closing the carbon loop.
"Our microbes turn pollution into polymers, exhaust into elastomers, and smoke into solvents."
"The greatest untapped resource in chemistry isn't in the ground—it's in our atmosphere." — SBRC-Nottingham Manifesto