Introduction

"There have been attempts to reduce atmospheric level of carbon dioxide in various approaches."

Since the Industrial Revolution, fossil fuels have been used to power industries and machines. As the world gets more industrialized in accordance with population growth, the demand for fossil fuels has grown more than ever. Due to drastic increase of fossil fuel consumption, massive amount of carbon dioxide (CO₂) has been emitted into the atmosphere and the amount is still growing. As carbon dioxide (CO₂) is considered to be a significant factor accelerating global warming, there have been numerous attempts to reduce the atmospheric level of carbon dioxide (CO₂). Administrators have ratified protocols to regulate the emission of carbon dioxide (CO₂). Scientists have endeavored to figure out ways to reduce this greenhouse gas despite several limitations.

As global warming triggered by petroleum is getting worse, petroleum buried underground has been depleted for a long time. So, people started to look for alternative energies like wind energy, hydro energy, tidal power, nuclear energy and solar energy. While petroleum can provide energy as well as various materials such as plastic or fabrics, conventional alternative energies like hydrogen energy could only be used as a source of energy.

We, Team KAIST, Korea, suggest an idea of carbon dioxide (CO₂) fixation with specially engineered bacterial strain which converts atmospheric carbon dioxide (CO₂) into meaningful biomass as well as consuming it.

Project Overview

CO₂ Fixation Pathway and Pathway Switching Module

1. CO₂ Fixation Pathway

Reductive acetyl-CoA pathway is a pathway for carbon dioxide (CO₂) fixation in many anaerobes. Acetogenic bacteria, or acetogens, use this pathway to synthesize acetic acid from carbon dioxide. This pathway allows acetogens to grow autotrophically using hydrogen(H₂) and carbon monooxide(CO) as electron donor and carbon dioxide (CO₂) as electron acceptor.[1]

Because the pathway is non-regenerative, reductive acetyl CoA pathway is a appropriate target pathway to consume atmospheric carbon dioxide (CO₂). Nowadays, full genome sequences of bunch of acetogens are available. Also, the enzymes consisting the pathway are elucidated allowing us to reconstruct the pathway in Escherichia coli.

[1] Environ Microbiol. 2008 October ; 10(10): 2550-2573.


2. Pathway Switching Module

Throughout past iGEM competitions, many kinds of bio-modules were proposed and tested. In our project, we are suggesting dual-phase switching module using DNA recombination system that is new to iGEM part registry. With this module we will be able to control metabolic pathway we are targeting.

• Module Suggestion and Proof of Concept
• Application of Module

Coupling of suggested module with cell growth and metabolic pathway, we expect our module enable our cells to control their metabolisms according to cell growth.

Hand-made Video