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Aragorn
11th May 2019, 17:51
Source: Science Daily (https://www.sciencedaily.com/releases/2019/05/190509142722.htm)




Discovery illuminates how bacteria turn methane gas into liquid methanol


https://www.sciencedaily.com/images/2019/05/190509142722_1_900x600.jpg


Known for their ability to remove methane from the environment and convert it into a usable fuel, methanotrophic bacteria have long fascinated researchers. But how, exactly, these bacteria naturally perform such a complex reaction has been a mystery.

Now an interdisciplinary team at Northwestern University has found that the enzyme responsible for the methane-methanol conversion catalyzes this reaction at a site that contains just one copper ion.

This finding could lead to newly designed, human-made catalysts that can convert methane -- a highly potent greenhouse gas -- to readily usable methanol with the same effortless mechanism.

"The identity and structure of the metal ions responsible for catalysis have remained elusive for decades," said Northwestern's Amy C. Rosenzweig, co-senior author of the study. "Our study provides a major leap forward in understanding how bacteria methane-to-methanol conversion."

"By identifying the type of copper center involved, we have laid the foundation for determining how nature carries out one of its most challenging reactions," said Brian M. Hoffman, co-senior author.

The study will publish on Friday, May 10 in the journal Science. Rosenzweig is the Weinberg Family Distinguished Professor of Life Sciences in Northwestern's Weinberg College of Arts and Sciences. Hoffman is the Charles E. and Emma H. Morrison Professor of Chemistry at Weinberg.

By oxidizing methane and converting it to methanol, methanotrophic bacteria (or "methanotrophs") can pack a one-two punch. Not only are they removing a harmful greenhouse gas from the environment, they are also generating a readily usable, sustainable fuel for automobiles, electricity and more.

Current industrial processes to catalyze a methane-to-methanol reaction require tremendous pressure and extreme temperatures, reaching higher than 1,300 degrees Celsius. Methanotrophs, however, perform the reaction at room temperature and "for free."

"While copper sites are known to catalyze methane-to-methanol conversion in human-made materials, methane-to-methanol catalysis at a monocopper site under ambient conditions is unprecedented," said Matthew O. Ross, a graduate student co-advised by Rosenzweig and Hoffman and the paper's first author. "If we can develop a complete understanding of how they perform this conversion at such mild conditions, we can optimize our own catalysts."

The study, "Particulate methane monooxygenase contains only mononuclear copper centers," was supported by the National Institutes of Health (award numbers GM118035, GM111097 and 5T32GM008382) and the National Science Foundation (award number 1534743).


Source: Science Daily (https://www.sciencedaily.com/releases/2019/05/190509142722.htm)




Note: While the article enthusiastically speaks of methanol as a fuel for automobiles et al, it must be noted that it is also a very dangerous fuel, because when methanol burns, it does so with a flame whose light exclusively falls within in the infrared spectrum. In other words, the fire of burning methanol is invisible to the human eye, which is why methanol is no longer allowed as a fuel or fuel additive in competitive motor sports. Ethanol on the other hand ─ which is already being used now as an important ingredient of the unleaded petrol/gasoline you fill your car with at European gas stations ─ is a lot safer in that regard.

Emil El Zapato
11th May 2019, 18:36
very interesting...such enzymes have been used for oil cleanup for a long time...quite a number of years ago that was a type of product that I marketed...I thought it was a really great product but I'm a poor salesman...no one ever seemed to trust me. As a demo, I used to poor the product into a frying pan with oil in it and one could literally watch the oil level drop. The byproduct was water vapor and oxygen. How could it possibly be better? I spent time traveling around the local chemical and oil plants leaving samples. What I got for my efforts was a notice that I would be reported to Homeland Security.

It was about that time that I learned that the Gulf area had literally no restrictions on dumping into the bay. Even a non-ecocentric person such as myself thought that was exceedingly strange. The pollution was everywhere. Simple public cleanup of parking lots etc were dumping volumes of runoff waste into the public water system...And when I would point it out I would just get a shrug of shoulders.

Chris
11th May 2019, 18:47
There are so many workable alternative fuel sources already available, it boggles the mind. Every time one is about to become mainstream, it is destroyed by the oil lobby. This is an actual conspiracy spanning at least a century, if not more and it keeps happening over and over again. The co-conspirators have been indicted several times, but they keep getting away with some minor fines and we keep burning fossil fuels and slowly poisoning ourselves in the process. I think it is the biggest scandal of the 20th and 21st centuries and we will look back at this period in disgust in a few decades' time.