Engineered Fusion Enzyme Boosts Production of Biofuels

Scientists working at the US Department of Energy's Brookhaven National Laboratory have constructed a fusion protein that increases the production of alkanes – long carbon-chain molecules similar to gasoline hydrocarbons that can be biologically synthesized and extracted as a renewable alternative to petrochemicals.

In an earlier experiment, the research team discovered that the alkane-producing enzyme known as aldehyde-deformylating oxygenase or ADO, which naturally makes alkanes in certain bacteria, could not prolong its activity during the process due to buildup of hydrogen peroxide, a toxic by-product that completely inhibits the enzyme. To mitigate this inhibition problem, the scientists molecularly fused the ADO enzyme with another enzyme, catalase, which degrades hydrogen peroxide to oxygen and water. Laboratory assays showed that the engineered bi-functional enzyme was able to run the reaction for over 225 cycles versus three cycles for the native ADO. Expression of the fusion protein in bacteria resulted in at least five-fold increase in alkane production compared with the use of ADO enzyme alone.

The results of this study are described in the Proceedings of National Academy of Sciences. Now the BNL scientists are preparing to take on another challenge - making the combo enzyme work with algae and green plants.