Wednesday, 21 September 2016

Engineered Bacterium Turns Carbon Dioxide into Methane Fuel

Methane Fuel

Bacterium Turns Carbon Dioxide into Fuel with Enzymatic Step

Scientists have brought about a bacterium which tends to take carbon dioxide from the air, turning it into fuel with a single enzymatic step. The process is said to draw on sunlight in producing methane and hydrogen within the bacterium Rhodopseudomonas palustris, in essence withdrawing combustion. The said engineered bacteria tend to guide scientists to an improved carbon-neutral biofuels.

Their results had been published recently by the researchers in the journal Proceedings of the National Academy of Science. According to co-author Caroline Harwood, professor of microbiology at the University of Washington, the report flourished from her work studying an enzyme known as nitrogenase. She commented that they were interested in the enzyme nitrogenase since it does a remarkably difficult reaction.

 The enzyme, in nature tends to serve as a catalyst to assist certain bacteria turn inert atmospheric nitrogen gas into reactive ammonia through a process known as nitrogen reduction or nitrogen fixation. The enzyme tends to utilise adenosine triphosphate –ATP which is a compound that assists as an energy exchange in cells.

Enzyme Type of Promiscuous

The nitrogen reduction reaction tends to have a big energy barrier and seldom occurs on its own without the enzyme. Researchers have been speculating if they could tweak nitrogenase to operate with other stable as well as inert molecules.

Harwood has commented that it has been somewhat appreciated recently that this enzyme is a type of promiscuous and tends to do other reactions, efficiently.Some of her co-workers succeeded in isolating and changing nitrogenase to use the most oxidized type of carbon, carbon dioxide as the initial material in producing the most reduced kind of carbon, methane.

However, this altered enzyme was dully produced in test tube at tiny scales that was not adequately good for a process which could someday produce industrial quantities of biofuels. Harwood had stated that they want to see if they could get a real living organism for this conversion. A form of the R palustris bacterium which had been modified to crank out the engineered nitrogenase at full blast had been prepared by the team.

Modified Nitrogenase Unable to Fix Nitrogen

The bacterium in its natural state tends to absorb sunlight in order to produce ATP so that light can assist in generating the energy to power the enzyme in the modified cells. The researchers discovered that the modified nitrogenase could not fix nitrogen though it could produce methane and hydrogen when the bacteria were illuminated.

But the latest nitrogenase is not anywhere as efficient in producing methane from carbon dioxide since it makes ammonia from nitrogen gas. Harwood has remarked that the normal enzyme tends to make about a couple of hydrogen from each molecule of ammonia and the changed enzyme tends to make a thousand of hydrogen for every molecule of methane.

An associate lecturer from the department of biological sciences at the University of Arkansas, Fayetteville, Daniel Lessner, not involved in the research had stated that the findings draw out a clear pathway in producing methane, the foremost constituent of natural gas from the living organisms. He had studied a class of bacteria known as methanogens which tend to produce methane, naturally.

But they tend to use various starting materials such as acetate. He commented saying that the methanogens need other microbes in providing them with the other electron donors and what is needed then is not just one microorganism but multiple microorganisms.