IISc-developed biocatalyst to power push for sustainable fuels

Bengaluru: A new enzymatic platform developed by researchers in the Indian Institute of Science (IISc) is promising a boost to production of hydrocarbons, compounds that are critical to sustainable fuel pathways.

Developed at IISc’s Department of Inorganic and Physical Chemistry (IPC), the platform is designed to transform naturally abundant and inexpensive fatty acids to valuable hydrocarbons called 1-alkenes that are promising biofuel alternatives to fossil fuels.

Hydrocarbons have potential as “drop-in” biofuels which can be blended and used with existing fuels and infrastructure, IISc said on Friday. They are widely used in polymer, detergent and lubricant industries. This makes enzymes that help mass-produce these hydrocarbons highly sought after.

The research, published in Science Advances, overcame limitations in the team’s previous study which involved a living cell membrane-bound enzyme called UndB that can convert fatty acids to 1-alkenes but gets inactivated after a few cycles.

The team addressed the challenge by creating an artificial fusion protein that combined UndB with another enzyme, catalase.

Tabish Iqbal, first author of the study and PhD student, said catalase degrades H2O2 (Hydrogen peroxide), a byproduct of the reaction process that was inhibiting UndB earlier. Adding catalase enhanced the enzyme’s activity 19-fold, from 14 to 265 turnovers, he said. A turnover indicates the number of active cycles an enzyme completes before getting inactivated.

The researchers created an artificial fusion protein combining UndB with catalase, by introducing a fused genetic code via carriers called plasmids into E. coli bacteria. E. coli, in the right conditions, act as “whole cell biocatalysts” and convert fatty acids to alkenes.

They found that by incorporating partner proteins in the genetically modified E. coli and feeding fatty acids, the conversion’s efficiency increased to 95 per cent.

Debasis Das, Assistant Professor at IPC and corresponding author, said a key advantage of this biocatalyst is that UndB does not produce unwanted side products. The team has applied for a patent and is looking for industry collaborators to scale up the new platform.