hydrogen using bacteria
American researchers have managed something amazing: They produce
cost-effective and environmentally friendly energy - and for sewage.
It is among the cleanest methods of power generation experts believe
that the use of hydrogen for a long time, because no carbon dioxide
produced during combustion that heats the Earth's atmosphere. Combined
in an engine, the molecules of the gas with one oxygen atom is the
result of chemical reaction - in addition to the energy released -
only pure water.
Sustained the power source is also. Because the basis for the reaction
in water is virtually inexhaustible exist on Earth.
High cost of some energy
To date, however, fails skimming a large volume of this source,
however, mainly because the hydrogen production itself is very energy
consuming. Because the gas is produced by the electrolytic
dissociation of water into water and oxygen. Only if the electrolysis
process required for this energy comes from renewable sources such as
wind power or solar power, hydrogen bears the title of "carbon
neutral" and rightly so. He is a true environmentally friendly fuel.
This problem has now Professor Bruce Logan in his
"electrically-assisted microbial fuel cell" solved with bacteria. The
unicellular organisms in an environment without oxygen decompose
organic waste and the pollution load in sewage from households, food
factories, or from farms. They split the organic material and excrete
it from the pure hydrogen. He is bubbling as gas bubbles from the
broth.
Cheap producers: bacteria
The first published online proceedings will be published in the
journal "Environmental Science and Technology." Logan and his
colleagues to produce up to four times more hydrogen directly from
water or biomass than managed so far. Because usually the natural
fermentation of the waste with bacteria limits are set: without an
extra energy boost from the outside can consume the carbohydrates of
the protozoa biomass only in narrowly limited in scope and thus split.
There always remains a sediment left on the end product, the bacteria
can not digest continues: as acetic and butyric acids.
"That's why we hurried along with mini-tension," Logan ventilated the
secret of his discovery, "already about 0.25 volts are sufficient to
overcome the bacterial fermentation of the threshold." This enabled
Bruce Logan and his colleagues measured the energy consumption as
opposed to the usual production method of hydrogen to one tenth of the
amount reduced.
Engineered bacteria are voracious
How far left as acetic or butyric acid end products remained Logan
bacteria digest now with the help of these additional energy. "The
process shows worldwide for the first time ever that we have the
potential to generate hydrogen as a basis for really clean mobility,"
said Logan, the results of research conducted by the National Science
Foundation, the U.S. Department of Agriculture and the Penn State Huck
Life Science Institute has been promoted.
"Basically, we use the same fuel cell, which is also utilized for
sewage treatment," said Bruce Logan, "but we continue the process
without oxygen, but under stress." If the bacteria then eat biomass,
they send electrons to the anode of the apparatus . They wander from
there via a wire to the cathode where they are - connect with the
"digestion" of the bacteria also caused protons (hydrogen atoms
without an electron), which float in the solution of hydrogen
molecules - excited by the voltage. The researchers call their special
fuel "BioElectrochemically-Assisted Microbial Reactor" (BEAMR).
The trick: Since there are many places on earth, is sewage-treatment
plants can be produced with the new method also almost everywhere in
the effluent hydrogen. "This," is Logan convinced. "Our system makes
it an economically very competitive method" In the end, so that is two
birds with the same stone: This is how the climate-friendly fuel of
the future manufacture and as a "waste product" receives one way
process of clean drinking water.
