Team:Wisconsin-Madison/Project

Abstract

Biofuels represent a potential solution to current world energy demands. Total crude oil replacement based on a 20% fuel titer and current fuel demands would require 5.6 trillion gallons of fresh water per year. Current fresh water supplies may not support this added demand. Alternatively, a sustainable approach may use a portion of the Earth’s 3.5x1020 gallons of ocean water. However, current fuel-producing organisms are unable to thrive in ocean-level osmolarities. Glycine betaine, a powerful osmoprotectant, shields organisms from salt-induced stress. Wild-type Escherichia coli can acquire glycine betaine from their surroundings or synthesize it from environmental choline. Two enzymes, glycine/sarcosine methyltransferase, and sarcosine/dimethyglycine methyltransferase, catalyze three successive methylations of glycine for de novo synthesis of glycine betaine. Here, we demonstrate an engineered E. coli with an increased growth rate under salt induced stress. We highlight utility by demonstrating the improved growth of fuel producing bacteria in ocean water.