Researchers at the Department of Inorganic and Physical Chemistry, Indian Institute of Science (IISc), had developed an enzymatic platform capable of efficiently converting naturally abundant and inexpensive fatty acids into valuable hydrocarbons known as 1-alkenes, which were promising biofuels. Considering the finite availability and polluting nature of fossil fuels, scientists were increasingly exploring sustainable fuel pathways involving hydrocarbons. These compounds showed significant potential as "drop-in" biofuels, which could be blended and used with existing fuels and infrastructure, according to the Bengaluru-based IISc.
These hydrocarbons could potentially be synthesized on a large scale using microorganism "factories." Enzymes facilitating the mass production of these hydrocarbons were highly sought after. Hydrocarbons also found extensive use in the polymer, detergent, and lubricant industries, IISc noted in a press release.
In a previous study, the IISc team had purified and characterized an enzyme called UndB, which was bound to the membranes of living cells, especially certain bacteria. It was capable of converting fatty acids to 1-alkenes at the fastest rate currently possible. However, the team discovered that the process was not very efficient, as the enzyme would become inactivated after just a few cycles.
Upon further investigation, they realized that H2O2, a byproduct of the reaction process, was inhibiting UndB. In the current study published in "Science Advances," the team had circumvented this challenge by adding another enzyme called catalase to the reaction mix. Tabish Iqbal, the first author of the study and a PhD student at IPC, explained that catalase degraded the H2O2 produced. Adding catalase enhanced the enzyme's activity 19-fold, from 14 to 265 turnovers (indicating the number of active cycles an enzyme completed before getting inactivated).
Excited by this finding, the team decided to create an artificial fusion protein combining UndB with catalase by introducing a fused genetic code via carriers called plasmids into E.coli bacteria. Under the right conditions, these E.coli would then act as a "whole cell biocatalyst," converting fatty acids and producing alkenes, the release said.
