System and method of optogenetically controlling metabolic pathways for the production of chemicals

Abstract

A system and method for controlling metabolic enzymes or pathways in cells to produce a chemical above the levels of a wild-type strain is disclosed. The system utilizes cells, including yeasts, bacteria, and molds, having at least two genes capable of being controlled bi-directionally with light, where one gene is turned from off to on when exposed to light and another gene is turned from on to off when exposed to light, the two genes reversing when the light is turned off. Cells may utilize any number of sequences that benefit chemical production, including sequences that: encode for constitutive transcription of light-activated transcription factor fusions; encode for a metabolic enzyme; encode for a repressor; induce expression of metabolic enzymes; and an endogenous or exogenous activator expressed by a constitutive promoter, inducible promoter, or gene circuit. These systems may be coupled to biosensors or protein cascade systems, enabling the monitoring or automation of the fermentation process to optimize production of a desired product. These systems may also allow for optimization and periodic operation of a bioreactor using light pulses.