workhorse °°° “Ralstonia metallidurans“ °°° - 500 Beiträge pro Seite

[esco7]

http://www.earth-pages.com/archive/economic.asp

Start für "Spiegelung" von:
Thread-Nr: 1111166

esco7

[esco7]

#12 von esco7 15.04.07 17:28:47 Beitrag Nr.: 28.826.095

Hat keinen direkten Bezug zu Gold, aber zeigt die Vielseitigkeit der Forschung über und mit Ralstonia metallidurans:

New 'biofuel cell' produces electricity from hydrogen in plain air
CHICAGO, March 26 2007
A pioneering “biofuel cell” that produces electricity from ordinary air spiked with small amounts of hydrogen offers significant potential as an inexpensive and renewable alternative to the costly platinum-based fuel cells that have dominated discussion about the “hy-drogen economy” of the future, British scientists reported here today.
The research was presented at the week-long 233rd national meeting of the American Chemical Society, the world’s largest scientific society.
Fraser Armstrong, Ph.D., described how his research group at Oxford University built the biofuel cell with hydrogenases — enzymes from naturally occurring bacteria that use or oxidize hydrogen in their metabolism. The cell consists of two electrodes coated with the enzymes placed inside a container of ordinary air with 3 percent added hydrogen.
That is just below the 4 percent danger level at which hydrogen becomes an explosion hazard. The research established for the first time that it is possible to generate electricity from such low levels of hydrogen in air, Armstrong said…………
“The technology is immensely developable,” Armstrong said. “We are at the tip of a large iceberg, with important consequences for the future, but there is still much to do before this generation of enzyme-based fuel cells becomes commercially viable. The idea of electricity from hydrogen in air, using an oxygen-tolerant hydrogenase is new, although other scientists have been investigating enzymes as electrocatalysts for years. Most hydrogenases have fragile active sites that are destroyed by even traces of oxygen, but oxygen tolerant hydrogenases have evolved to resist at-tack.”
The biofuel cell has a number of advantages over conventional fuel cells, devices that convert the chemical energy in a fuel into electricity without combustion, Fraser explained. A hydrogen fuel cell uses hydrogen and oxygen, producing water as the only waste product. Platinum is the most commonly used catalyst in conventional (proton exchange membrane) fuel cells, making the devices an expensive alternative energy source with sharply limited uses.
The biofuel cell uses enzymes from Ralstonia metallidurans (R. metallidurans), an ancient bacterium believed to have been one of the first forms of life on Earth. It evolved 2.5 billion years ago, when there was no oxygen in Earth’s atmosphere, and survived by metabolizing hydrogen.
One focus of Armstrong’s research is understanding how the active site of the R. metallidurans hydrogenase developed the ability to cope with oxygen as Earth’s atmosphere changed. ……….
### — Michael Woods
Fraser Armstrong, Ph.D., is with the Department of Chemistry, Oxford University, London, England

[esco7]

R. metallidurans is a marvel of nature that thrives in acutely toxic heavy metal loaded environments (mM's of metal cations!)

...Ralstonia metallidurans is a natural isolate that was found in the sediments of a Belgian zinc metallurgical plant. This bacteria is resistant against a large number of heavy metals including Ag(I), Cd(II), Co(II), Cu(II), Hg(II), Ni(II), Pb(II), Tl(I) and Zn(II)...metal-resistant Ralstonia, through evolution, are particularly well adapted to the harsh environments typically created by extreme anthropogenic situations...Ralstonia is better able to withstand high concentrations of heavy metals than any other organism. 13% of all genes in Rme encode transport proteins. Nearly one-third of the transporters identified (32%) appear to function in inorganic ion transport with three-quarters of these acting on cations. For every kind of resistance mechanism, the R. metallidurans genome ranked first for the variety of gene or gene cluster versions. The main illustration of this fact is the family of three component efflux of toxic compounds: most of the genomes contain 0 to 4 versions of this gene family: there are 12 of them in R. The genome of this bacterium contains also 8 P-type ATPase involved in metal efflux specialized in lead, cadmium, thallium and/or copper efflux, and several others mechanisms involved in metal processing. There are also new proteins (mostly encoded by the large plasmids) that were, up to now, never described in other bacteria.


http://shkrobius.googlepages.com/wondersofnatureending


°°°°
esco7

[esco7]

Vom Thema abschweifende Ausschweifung:

How to make cheap wine taste like a fine vintage
17 December 2008 by Stephanie Pain

MOST people have got one lying around somewhere: a bottle of cheap, nasty wine left over from a dinner party just waiting to be offloaded on someone else - or quaffed late one night when the good stuff has run out. But what if you could turn that bargain-basement plonk into fine wine in minutes? In these straitened times it could be just the thing a wine lover needs.
Traditionalists, of course, would insist that nothing can replace genuine quality plus long, slow ageing in an oak barrel and years of storage in cool, cobwebby cellars. But could there be a short cut?
Over the years, inventors have come up with dozens of widgets that they claim can transform the undrinkable or bring the finest wines to perfection without the long wait. Sadly, there's little scientific evidence that most of them work (see "Faking it"). Looks like you're stuck with the plonk.
Or are you? Fortunately, there is one technique that stands out from the rest. It is backed by a decade of research, the results have been published in a peer-reviewed journal and the end product has passed the ultimate test- blind tasting by a panel of wine experts. No fewer than five wineries have now invested in the technology.
The secret this time is an electric field. Pass an undrinkable, raw red wine between a set of high-voltage electrodes and it becomes pleasantly quaffable. "Using an electric field to accelerate ageing is a feasible way to shorten maturation times and improve the quality of young wine," says Hervé Alexandre, professor of oenology at the University of Burgundy, close to some of France's finest vineyards.
No matter how impatient or undiscriminating you may be, fresh wine is undrinkable and can have horrible after-effects. Expect an upset stomach, a raging thirst and the world's nastiest hangover. The youngest a wine can be drunk is six months. Most, especially reds, take longer to achieve the required balance and complexity. The finest can take 20 years to reach their peak.
During ageing, wine becomes less acid as the ethanol reacts with organic acids to produce a plethora of the fragrant compounds known as esters. Unpleasant components precipitate out and the wine becomes clearer and more stable. Red wines mellow as bitter, mouth-puckering tannin molecules combine with each other and with pigment molecules to form larger polymers, at the same time releasing their grip on volatile molecules that contribute to the wine's aroma.
These reactions take time and need a small but steady supply of oxygen. In barrel-aged wines, oxygen leaks through the wood, while wine matured in steel tanks is often helped along by introducing microscopic oxygen bubbles.
There are good commercial reasons why winemakers would love get their hands on a speedier alternative, especially in places like China where the industry is young and booming. It would allow them to get their wines into the shops faster to meet ever-increasing demand, and cut the cost of storage.
The food industry has experimented with electric fields as an alternative to heat-treating since the 1980s, and 10 years ago Xin An Zeng, a chemist at the South China University of Technology in Guangzhou, decided to see what he could do for wine. Early results were promising enough for Zeng and his colleagues to develop a prototype plant in which they could treat wine with fields of different strengths for different periods of time.
They pumped the wine through a pipe that ran between two titanium electrodes, fed with a mains-frequency alternating supply boosted to a higher voltage. For the test wine, the team selected a 3-month-old cabernet sauvignon from the Suntime Winery, China's largest producer. Batches of wine spent 1, 3 or 8 minutes in various electric fields (see diagram). The team then analysed the treated wine for chemical changes that might alter its "mouth feel" and quality, and passed it to a panel of 12 experienced wine tasters who assessed it in a blind tasting (Innovative Food Science and Emerging Technologies, vol 9, p 463).
The results were striking. With the gentlest treatment, the harsh, astringent wine grew softer. Longer exposure saw some of the hallmarks of ageing emerge- a more mature "nose", better balance and greater complexity. The improvements reached their peak after 3minutes at 600 volts per centimetre: this left the wine well balanced and harmonious, with a nose of an aged wine and, importantly, still recognisably a cabernet sauvignon.
Analysis revealed some significant chemical changes. Most obviously, there was a marked increase in reactions between alcohols and acids to produce esters. This led to a reduction in concentrations of the long-chain alcohols known to be responsible for nasty odours and a burning mouth feel, while the increase in the concentration of esters boosted the aroma and the perception of fruitiness.
Two other good things happened: the breakdown of proteins produced free amino acids that contribute to taste and there was a noticeable reduction in the levels of aldehydes, which are responsible for "off" flavours. You can have too much of a good thing, though. Upping the voltage and applying it for longer brought new and unwanted changes, including the generation of new undesirable aldehydes. Zap it too much and the result, the panel found, was worse than the untreated original.
Although Zeng cannot yet explain how exposure to an electric field alters the wine's chemistry, his results show that under the right conditions the technique can accelerate some aspects of the ageing process. "Not only can it shorten a wine's normal storage time, it can also improve some lower-quality wine," he says. "It works just as well with other grape varieties such as merlot and shiraz." Five Chinese wineries have begun trials.
A quick blast with an electric field can improve lower-quality wine and shorten storage time
Sadly for wine drinkers feeling the pinch, there's no immediate prospect that you can try this for yourself. "I have thought of designing a set of equipment for use at home," admits Zheng "...but not yet."

Faking it
Hervé Alexandre, professor of oenology at the University of Burgundy, rates some of the latest attempts to speed-age wine.ULTRASOUNDDevices based on ultrasound pop up regularly. October saw the launch of the Quantum Wine Ager, which its inventor claims will turn a £3.99 bottle of plonk into something that tastes as if it costs hundreds.Verdict: "I'm a bit sceptical. Ultrasound might increase some reactions but a lot of rigorous experiments must be done before concluding that it works. When the wine is of low quality there is no miracle that will transform it into a bottle of the finest vintage."UNDERSEA CELLARAGEChampagne house Louis Roederer has consigned several dozen bottles of champagne to the ocean floor, where it reckons the cool water and gentle rocking by currents will accelerate ageing.Verdict: "By lowering the temperature you slow down chemical reactions, so storage in cold water will slow the ageing process. Corks are permeable to oxygen, which helps ageing. While in water, no oxygen will enter the bottle."GAMMA RADIATIONAccording to Chinese researchers, an hour's treatment improved the flavour of new rice wine. In Canada the technique has been used to get rid of "ladybeetle taint"- nasty off flavours that result from ladybeetles (ladybirds) being pressed along with the grapes.Verdict: "It sounds technically interesting, but I'm not sure consumers are ready for irradiated wine."

http://www.newscientist.com/article/mg20026873.500-how-to-ma…


°°°°°
esco7