Metabolomics of Carbon-Fixing Mutants of Cyanobacteria by GC/Q-TOF

Mutants of the model cyanobacterium Synechococcus elongatus were evaluated by untargeted metabolomics to identify possible phenotypic changes that allow more efficient growth. The mutants were analyzed using the Agilent 7200 Series GC/Q-TOF, and changes in metabolite profiles were evaluated using Agilent Pathway Architect Software in Mass Profiler Professional. This approach identified a number of metabolic pathways as possible targets that could explain the improved phenotype of the mutants. Introduction Due to the finite availability of fossil fuels, as well as detrimental accumulation of CO2 emissions, there is great interest in engineering microorganisms to generate sustainable fuel alternatives. Cyanobacteria, photosynthetic carbon dioxide–fixing microorganisms, are especially attractive for their ability to use the greenhouse gas as a carbon source, and light as an energy source. However, for cyanobacteria-based biofuels to be economically feasible, cellular growth rates must be improved, as the major obstacle to industrial-scale production are low yields [1]. Previous studies have shown that carbon fixation is a key limitation in cyanobacterial growth [2]. However, many past attempts to increase the rate of carbon fixation by directed changes have yielded only minimal improvements. Thus, a directed evolution approach may allow identification of beneficial metabolic changes that had not previously been considered.