2023 AIChE Annual Meeting
Characterization of Phzmpp and Directed Evolution for Novel Phenazine Production
Phenazines are planar, nitrogenous heterocyclic compounds that are natively produced by Pseudomonads. These chemicals are redox-active pigmented compounds identified for use in antibiotics, dyes, and electrochromic redox mediation. Two enzymes (PhzM and PhzS) are known to decarboxylate phenazine-1-carboxylic acid (PCA) in tandem to produce pyocyanin, a blue-colored phenazine. Recently, a strain of pseudomonas was reported to methylate PCA to 5-methyl-phenazine-1-carboxylic-acid (5MPCA) with a previously undiscovered methyltransferase. We identified and recombinantly expressed the methyltransferase (PhzMPP) in E. coli and characterized its native activity. We performed directed evolution experiments PhzMPP, screening for mutants with the ability to convert phenazine to 5-methyl-phenazine, a non-native metabolite. Kinetic rate constants for both the wild type and the best mutant PhzMPP were determined. New mutant enzymes that can readily produce non-native phenazines will be useful for a number of applications including emerging energy technologies where organic redox mediators can be used for large scale energy storage.