Interfacing Chemical Catalysis with Engineered Microbes to Expand Biomass-Sourced Materials

PROJECT NUMBER: 29

AUTHOR: Varsha Selvam, Chemical and Biological Engineering

MENTOR: Dylan Domaille, Chemistry | MENTOR: Kelsey Stewart, Chemistry

ABSTRACT

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Biofuels and bio-sourced chemicals have a number of advantages over those of traditional fossil-fuel based chemical production. Major efforts in the field of metabolic engineering have enabled microbial production of biofuels and pharmaceuticals; however, it remains challenging to express biosynthetic pathways assembled from enzymes sourced from different organisms. To address this problem, we are exploring the hypothesis that synthetic catalysts can intercept metabolic intermediates and redirect flux to target chemicals without the need to engineer the organism. Our recent work has shown that a bio-sourced alcohol can be converted into the industrial chemical, 2-ethyl-2-hexenal (2-EH) in good yield (78%) at 28°C in aqueous buffer, which is in contrast to the current industrial production that requires fossil-fuel feedstocks, high temperatures, and precious metal catalysts.
Based on these initial studies, we hypothesized that E. coli that had been engineered to produce butyraldehyde, a key building block of 2-EH production, could be combined with a synthetic catalyst to deliver 2-EH directly from glucose. To identify a suitable catalyst, all 20 amino acids were screened for their ability to carry out the conversion of butyraldehyde to 2-EH in M9 media and at 37°C. This screen identified lysine and histidine as capable of directly converting n-butryaldehyde to 2-EH at the levels that an engineered strain of E. coli, developed by Dr. Ethan Lan’s laboratory (National Chiao Tung University, Taiwan), can produce. Our current efforts are focused on merging this engineered microbe with the identified catalysts to deliver a high-yield industrial chemical, in mild aqueous conditions, directly from glucose feedstocks.

VISUAL PRESENTATION

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AUTHOR BIOGRAPHY

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Varsha Selvam is a junior in the Chemical and Biological Engineering department at Mines. She pursues a major in Chemical Engineering with a biological focus and a minor in Biomedical Engineering. Currently, she is conducting research under Dr. Dylan Domaille and graduate mentor Kelsey Stewart. The research project explores biocompatible chemistry and its applications to biomass conversion. Varsha hopes to continue researching and working in the pharmaceuticals industry, integrating her interests in the medical and engineering fields.

Sponsored by Phillips 66