Why did we select our project?
• Carbon emissions are causing environmental issues.
• We are depleting fossil fuels
• E. coli can produce various alcohols through anaerobic respiration
• Using E. coli to produce alcohols is inexpensive
• E. coli starts to decompose the alcohol produced when it reaches it’s toxic level; therefore, increasing the E. coli's alcoholic resistance is crucial for increasing the alcohol production
• Energy density similar to that of gasoline
• Can be used in current systems immediately
• Inexpensive to produce
Alcohol Production Pathways
Figure 2: Alcohol Production Pathways are shaded in green while energy and amino acid production pathways are in blue. Grey boxes designate enzymes.
As shown in these figures, alcohol production in E. coli is closely linked to glycolysis, the Krebs cycle, and to amino acid synthesis. Pyruvate is the central molecule for all of these pathways. This means that if too much Pyruvate is diverted to alcohol production, less will be available for cellular respiration, possibly leading to an increased metabolic load for the bacteria.
Figure 3: isobutanol production pathway E. coli
In E. coli, the gene glmS produces Glucosamine-6-Phosphate which is an important metabolite of isobutanol tolerance. glmS has a self-regulation mechanism: the enzymatic activity of the protein GlmS activates a ribozyme that accelerates the self-cleavage of the glmS mRNA which regulates the expression of the glmS gene. The small RNA GlmZ activates glmS by stabilizing glmS transcription. Overexpression of the small RNA glmY can also upregulate the expression of glmS by upregulating glmZ.