Application of a Light Switchable System in Redirecting Escherichia coli Metabolic
Optogenetics has gained increasing attention to address reversibility and media invasiveness in biochemical engineering. The purpose of this project is to investigate the application of a genetically engineered light-switchable system, Cph8-OmpR, for controlling the accumulation of the useful central metabolite glucose-6-phosphate (G6P) in Escherichia coli. This could be accomplished by linking expression of an adaptor protein, SspB, which increases enzyme phosphofructokinase (Pfk) degradation, with different light intensities. Pfk is the enzyme that catalyzes fructo-6-phosphate (F6P), an isomer of G6P from an equilibrium reaction, for downstream metabolism. This step is considered the major control point of G6P accumulation in the experimental bacterial strain. A mathematical model was successfully established for this system and indicated that lower red-light exposure resulted in higher intracellular G6P concentration. A construct for experimental tests was successfully made, but more work on plasmid construction and strain modification is required for future experiments.