Scientists crafted a chimeric enzyme by fusing UndB with catalase to increase its efficiency. Credit: Iqbal, T. et al.
UndB, a membrane-bound bacterial enzyme, can convert naturally abundant fatty acids to 1-alkenes, a type of hydrocarbon that could be used as next-generation biofuels1.
Researchers at the Indian Institute of Science in Bengaluru say the alkenes could also be used as green chemicals in industries that make polymers, detergents, and lubricants.
The enzyme, found in the bacterium Pseudomonas mendocina, has a diiron centre at its active site and depends on redox reactions and oxygen. Despite its discovery a decade ago, UndB’s catalytic efficiency has been poor, limiting its use for 1-alkene production.
To find out if this could be improved, the team, led by Debasis Das, first purified the enzyme. They found that it works optimally at 25°C and catalyses the conversion of medium-length fatty acids to 1-alkenes, but loses its efficiency after a minute.
The scientists traced this deficiency to hydrogen peroxide's inactivation of UndB. To work around this, they produced a chimeric enzyme by fusing UndB with catalase. This countered the inhibitory effects of hydrogen peroxide.
They then used the engineered enzyme to develop a whole-cell biocatalytic system that converted free fatty acids to 1-alkenes with up to 95% efficiency.
The whole-cell biocatalyst can sustainably produce 1-alkenes. It will contribute to a greener future, by reducing our reliance on fossil fuels, says Das.
