Team:Monash Australia/Project


Revision as of 03:59, 10 September 2010 by Grug (Talk | contribs)

Overall project

Monash University having a heavy movement to reduce the impact humans have on the planet has inspired our first iGEM project. After some initial research, we pondered on the concept of degrading plastics or cellulose into useable components. After discovering this has been a heavy focus by a number of different groups and past iGEM teams, so we then decidesd to look into producing some sort of useful product. After some investigation, we found that ethylene is a heavily used organic compound that is also naturally produced by plants. With our heavy reliance on this compound for plastics and in the food industry, we believe that it may be possible to develop a system that one day could be capable of replacing current production methods.

So what is ethylene used for?
Just about anywhere you go in the world you can find an ethylene based product. Ethylene can be polymerised to create products such as; detergents, plasticisers, synthetic lubricants and additives, but also as co-monomers in the production of polyethylenes; Oxidised to create surfactants and detergents, and ethylene glycol; Halogenation and hydrohalogenation to produce products PVC, Polyvinylidene chloride and ethyl bromide; Alkylation to produce styrene; and itself used as a fuel source and to ripen fruit.

How do we make ethylene
To produce ethylene there is a huge requirement of energy, Ethylene is produced in the petrochemical industry by steam cracking. In this process, gaseous or light liquid hydrocarbons are heated to 750–950 °C, inducing numerous free radical reactions followed by immediate quench to stop these reactions (−157 °C). This process converts large hydrocarbons into smaller ones and introduces unsaturation. Ethylene is separated from the resulting complex mixture by repeated compression and distillation. The average ethtlene producing plant requires 34,000 kW cracked gas compressor, a 22,000 kW propylene compressor, and a 11,000 kW ethylene compressor, equating to a huge amount of energy required. Currently the main source of ethylene is from distilation of crude oil and natural gas, as well as catalytic steam cracking which precusors are again fossil fuels.

How do plants make ethylene
Plants also create ethylene. Ethylene is a plant hormone, which can induce plants to grow and fruit to ripen. in plants the biosynthesis of the ethylene occurs in three steps and starts with conversion of the amino acid methionine to S-adenosyl-L-methionine (SAM) by the enzyme SAM synthase. SAM is then converted to 1-aminocyclopropane-1-carboxylic-acid (ACC) by the enzyme ACC synthase. The final step involves the action of the enzyme ACC-oxidase to oxidiase ACC to ethylene.

So what are the more common items we can relate to?

Linear Low Density Polyethylene - Plastic wrap (and prank material)

Low Density Polyethylene - Soft Plastic Bottles

Medium Density Polyethylene - Pipes

High Density Polyethylene - Hard Plastic bottles

Ultra High molecular weight Polyethylene - Bullet proof vests

PVC (polyvinal chloride)- Pipes

Polystryene - Packing material and insulation (also prank material)

Polyethylene Glycol - Anti-Freeze

Experimental plan

We set out to attempt to use the plant ethylene synthesis machinery in e. coli to make e. coli into ethylene producing factories, therefore remove the need for the high energy steam cracking process and decrease the reliance of fossil fuels to produce ethylene.

Our plan is to clone the enzymes from plant and....