Difference between revisions of "Team:Hong Kong-CUHK/Description"

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ABCDE(AzotoBacter vinelandii in Carbon Dioxide to methane Energy)

Objective

This project utilize modified nitrogenase in Azotobacter vinelandii to convert carbon dioxide(CO2) to methane(CH4).

Background and Significance

With the exploitation of carbon based fossil fuels, we sought for an alternative solution to combat the global energy crisis by utilizing a gas pollutant – CO2 through carbon fixation. To maintain current living standard, alternative energy sources are unprecedentedly demanding. We are now engineering a bacteria Azotobacter vinelandii to econvert CO2 into CH4 inside the bacteria Azotobacter vinelandii. A.vinelandii is a facultative areobe with an intracellular anaerobic environment which is essential for the reduction reactions.

Why CH4?

CH4 produced can serve as a fuel and any CO2 produced during the process can be returned to the system to CH4 generation. Comparing to hydrogen(H2), a popular alternative energy source, because of its "cleanliness after combustion, from the perspective of fuel storage, storage of CH4 is cheaper than that of H2 due to a lower boiling point. Thus it requires less energy to liquefy. Our engineered bacteria would also be able to convert the greenhouse gas CO2 into CH4 in closed systems, which eliminates the disadvantage of using CH4 as a fuel. Additionally, no change needed to be made on current car engines, which are designed to use of hydrocarbon fuels.

Goal to be achieved

From literatures, we found out that the carbon fixation process is not efficient enough, as most energy is wasted in H2 production. Therefore, we are tackling the fixation efficiency through two approaches: (1) the enhancing H2 reaction chain, and (2) increasing intracellular CO2 concentration.

MNOPQ(Magnetic Nanoparticles On Particular Requirement)

Objective

We aim to produce magnetic nanoparticles to meet certain requirements. Azotobacter vinelandii is also used in this project because it provides an intracellular anaerobic condition that is essential for the prduction processes.

Background and Significance

Magnetosome is an organelle with magnetic iron crystal (magnetite) by lipid bilayer which is originated from bacteria such as Magnetospirillum gryphiswaldense. It serves as a navigational device in magnetotactic bacteria by interacting with the Earth magnetic field. Magnetic beads formed could be applied in various aspects. Biomolecules, such as enzymes and antibodies, can be expressed on the magnetosome so that they can be easily controlled by magnet for specific purposes.

Unfortunately, most of the magnetotactic bacteria require microaerobic conditions for magnetosome biogenesis, which is hard to maintain with normal lab equipment. We are transferring essential genes for magnetosome formation into A. vinelandii, a facultative aerobe with an intracellular anaerobic environment, in the hope of producing magnetic beads with functional biomolecules under aerobic conditions with greater yield. We are also modifying the transmembrane protein presented on magnetosome membrane by fusing with biomolecules. Reactions could be more accelerated as the magnetic beads generated magnetosome provides a greater surface area to volume ratio than that artificial magnetic beads.

Applications

One of the applications is to use engineered magnetites to capture heavy metal ion in water. Different kinds of heavy metal ions such as Pb, Cu and Ni are found in marine system. By expressing different heavy metal binding proteins onto magnetic beads, heavy metal ions could be captured and be easily removed by magnet. It is better than the previou methods, in terms of operating cost, efficiency and eco-friendliness.