P lab

Synthetic Biology: Manufacturing Molecules Through Enzyme Engineering

We are developing new bio-manufacturing processes for two chemicals (butanone and 2-butanol) that are currently produced from petroleum. Butanone is a key ingredient in paints, varnishes and adhesives, while 2-butanol is converted into synthetic rubbers (particularly car tyres). The worldwide markets for these chemicals are in the millions of tonnes, and billions of dollars, per year. However, the global chemical industry is seeking new ways to manufacture them, which are not reliant on the fickle (and unsustainable) petroleum market.

A successful New Zealand-founded biotechnology company, LanzaTech Inc, has a gas-eating bacterium (Clostridium autoethanogenum) that efficiently converts waste gases (carbon monoxide and carbon dioxide) into bioethanol. The microbe also produces a chemical building block, 2,3-butanediol. We are engineering new enzymes that convert 2,3-butanediol into butanone and 2-butanol. The required functions are being engineered by taking existing enzymes with related activities, and accelerating their evolution in vitro. We are testing our engineered enzymes in Escherichia coli. In the the next phase of the project, the engineered enzymes will be incorporated into the LanzaTech microbe and the new strains will be optimized for commercial butanone and 2-production. This research is being funded by an MBIE Smart Ideas grant.

Synthetic pathways
Enzymatic pathways for manufacturing chemicals. Reactions and compounds occurring natively in the LanzaTech bacterium, C. autoethanogenum, are shown in black and grey. We are engineering enzymes for the conversion of 2,3-butanediol (green) to butanone and 2-butanol. A heterologous pathway for producing isopropanol, utilizing an alcohol dehydrogenase that we have characterized and engineered (Köpke et al., 2014; Maddock et al., 2015), is shown in blue.