Fermentation

Composite number

Physics

Engineering

Macroeconomics

Carbon fibers

Composite material

Economics

Keynesian economics

Organic chemistry

Biochemical engineering

Chemistry

Materials science

SCALE-UP

Production (economics)

Scale (ratio)

Acetone

Food science

Environmental science

Pulp and paper industry

Waste management

Quantum mechanics

Classical mechanics

Industrial production

Nature Biotechnology

Many industrial chemicals that are produced from fossil resources could be manufactured more sustainably through fermentation. Here we describe the development of a carbon-negative fermentation route to producing the industrially important chemicals acetone and isopropanol from abundant, low-cost waste gas feedstocks, such as industrial emissions and syngas. Using a combinatorial pathway library approach, we first mined a historical industrial strain collection for superior enzymes that we used to engineer the autotrophic acetogen Clostridium autoethanogenum. Next, we used omics analysis, kinetic modeling and cell-free prototyping to optimize flux. Finally, we scaled-up our optimized strains for continuous production at rates of up to ~3 g/L/h and ~90% selectivity. Life cycle analysis confirmed a negative carbon footprint for the products. Unlike traditional production processes, which result in release of greenhouse gases, our process fixes carbon. These results show that engineered acetogens enable sustainable, high-efficiency, high-selectivity chemicals production. We expect that our approach can be readily adapted to a wide range of commodity chemicals. Two industrial chemicals are sustainably produced at large scale by microbial gas fermentation.

Carbon-negative production of acetone and isopropanol by gas fermentation at industrial pilot scale