Friday, 26 August 2016

Sunlight and carbon dioxide turned into methane

With the problem of increasing carbon dioxide levels, many are trying to find ways to change this gas into something useful. Some scientists have recently engineered bacteria to do just that.


Rhodopseudomonas palustris
Make the bacteria do it!
Kathryn Fixen and her team have recently engineered a bacterium, Rhodopseudomonas palustris, to make methane from carbon dioxide. By tweaking the enzyme nitrogenase, which normally creates ammonia, scientists have managed to make it catalyze the reaction of carbon dioxide (CO2) to methane (CH4). They then managed to modify the R. palustris bacterium to make it mass produce the engineered nitrogenase. Since this bacteria can use sunlight as a source of energy, it is easier to create a large amount of this enzyme using natural sources. This makes it both eco-friendly and efficient.

Use of methane

Methane is the principal component of natural gas, which can be found in large bubbles in the soil all over our planet.  If you live in a cold country, you would use this to warm your house. It can also be used to make electricity and to power certain vehicles. Some people also cook on natural gas. This versatility of this gas makes it useful in many daily scenarios.

Not yet perfect
The other method which wo
uld be used to make methane would be through the use of methanogens. These microorganisms naturally produce methane and can be found in many different places including the human large intestine. The only problem with them is that they require different materials such as acetate to make methane and they can’t make it without the help of other microorganisms. This means that it requires multiple steps for the reaction to happen. With the new method though, the reaction happens in one step. As well as this, it can happen in a living organism, this means that it can happen at room temperature. Another advantage to this method is that it makes it easy to tweak since there is only one main step which needs to be changed. But, even with with all of its advantages, this engineered nitrogenase is still not as efficient at transforming compounds as the natural nitrogenase. “The normal enzyme makes about two hydrogens for every [molecule of] ammonia,” Co-author Caroline Harwood said. “The altered enzyme makes a thousand hydrogens for every molecule of methane.”

Ongoing research
The research is still going on as the scientists are attempting to find a way to increase the efficienc
y of the enzyme. Who knows, maybe some time in the future we will be reliant on these bacterium to create fuels for all of us to live a sustainable life.

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Sources:
http://faculty.college-prep.org/~bernie/sciproject/project/Kingdoms/Bacteria3/methanogens.gif