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Heterologous Production of Isopropanol Using Metabolically Engineered Acetobacterium woodii Strains
Franziska Höfele1, Teresa Schoch2, Catarina Oberlies2
1Institute of Molecular Biology and Biotechnology of Prokaryotes, Ulm University, 89081 Ulm, Germany.
Bioengineering (Basel, Switzerland)
|December 23, 2023
Summary
Acetogenic bacteria were engineered to produce isopropanol from carbon dioxide and hydrogen. This study optimized the microbial fermentation process, achieving a 2.5-fold increase in isopropanol yield.
Area of Science:
- Biotechnology
- Synthetic Biology
- Microbial Engineering
Background:
- Fossil fuel depletion and CO2 emissions necessitate sustainable chemical production.
- Acetogens metabolize CO or CO2 (+H2) via the Wood-Ljungdahl pathway, offering a fossil-independent alternative.
- Isopropanol is a widely used industrial chemical, driving the need for sustainable production methods.
Purpose of the Study:
- To develop a microbial fermentation process for fossil-independent isopropanol production.
- To engineer *Acetobacterium woodii* for enhanced isopropanol synthesis using specific enzymes.
Main Methods:
- Plasmid-based expression of key enzymes: thiolase A, CoA-transferase, acetoacetate decarboxylase, and secondary alcohol dehydrogenase.
- Utilized genes from *Clostridium scatologenes*, *C. acetobutylicum*, and *C. beijerinckii*.
- Optimized the engineered strain to overcome pathway bottlenecks.
Main Results:
- Achieved a maximum isopropanol production of 5.64 ± 1.08 mM using CO2 + H2.
- Engineered *Acetobacterium woodii* demonstrated successful isopropanol synthesis.
- Strain optimization led to a 2.5-fold increase in isopropanol concentration.
Conclusions:
- Successful microbial production of isopropanol from CO2 and H2 was demonstrated.
- Engineered acetogens offer a viable route for sustainable isopropanol manufacturing.
- Further optimization holds potential for significantly higher yields.
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