11-15-2007, 01:31 AM
By Roger Highfield, Science Editor
The dream of using hydrogen, the most plentiful element in the universe, as a green fuel to cut climate change moves a step closer today with the announcement that it can be made with the help of bacteria.
Hydrogen fuel cell technology powers Honda's Puyo
Public transport systems worldwide are moving toward hydrogen-powered engines as an alternative to petrol engines, because they burn hydrogen to produce only water. But the problem is that most hydrogen available today is produced by expensive processes that require the burning of polluting fossil fuels, such as natural gas.
Now scientists have developed a method that relies on bacteria in a specially designed reactor that can efficiently produce hydrogen fuel from any type of biodegradable organic matter, so that a glorified compost heap could protentially provide an abundant source of the clean-burning energy.
Dr Shaoan Cheng and Prof Bruce Logan of Penn State University, Pennsylvania, devised a method of hydrogen production that relies on combining electron-generating bacteria and a small electrical charge in a "microbial electrolysis cell" to belch out hydrogen gas.
They report today in the Proceedings of the National Academy of Sciences how they grew bacteria from soil or waste water in cells modified to increase bacterial growth and electrical current generation. Using acetic acid, a common waste product of industrial fermentation, the authors' reactor generated hydrogen gas at efficiencies up to 99% of the theoretical maximum yield. "This process produces 288 per cent more energy in hydrogen than the electrical energy that is added to the process," says Prof Logan.
advertisementUsing this process, which they have christened electrohydrogenesis, " efficient and sustainable hydrogen production is possible from any type of biodegradable organic matter." And they say that it offers advantages over the production of ethanol from biofuels, which "presents substantial technical challenges."
For example, if it is made using fermentation, then it takes energy hungry processes to purify the ethanol so it can be used in petrol. "The energy focus is currently on ethanol as a fuel, but economical ethanol from cellulose is 10 years down the road," says Prof Logan.
"There are substantial infrastructure issues to be addressed in using hydrogen gas, but the environmental and energy-conversion efficiency benefits for hydrogen as a transportation fuel makes it worth addressing and solving these issues," conclude the authors.
http://www.telegraph.co.uk/earth/main.jh...dro112.xml
The dream of using hydrogen, the most plentiful element in the universe, as a green fuel to cut climate change moves a step closer today with the announcement that it can be made with the help of bacteria.
Hydrogen fuel cell technology powers Honda's Puyo
Public transport systems worldwide are moving toward hydrogen-powered engines as an alternative to petrol engines, because they burn hydrogen to produce only water. But the problem is that most hydrogen available today is produced by expensive processes that require the burning of polluting fossil fuels, such as natural gas.
Now scientists have developed a method that relies on bacteria in a specially designed reactor that can efficiently produce hydrogen fuel from any type of biodegradable organic matter, so that a glorified compost heap could protentially provide an abundant source of the clean-burning energy.
Dr Shaoan Cheng and Prof Bruce Logan of Penn State University, Pennsylvania, devised a method of hydrogen production that relies on combining electron-generating bacteria and a small electrical charge in a "microbial electrolysis cell" to belch out hydrogen gas.
They report today in the Proceedings of the National Academy of Sciences how they grew bacteria from soil or waste water in cells modified to increase bacterial growth and electrical current generation. Using acetic acid, a common waste product of industrial fermentation, the authors' reactor generated hydrogen gas at efficiencies up to 99% of the theoretical maximum yield. "This process produces 288 per cent more energy in hydrogen than the electrical energy that is added to the process," says Prof Logan.
advertisementUsing this process, which they have christened electrohydrogenesis, " efficient and sustainable hydrogen production is possible from any type of biodegradable organic matter." And they say that it offers advantages over the production of ethanol from biofuels, which "presents substantial technical challenges."
For example, if it is made using fermentation, then it takes energy hungry processes to purify the ethanol so it can be used in petrol. "The energy focus is currently on ethanol as a fuel, but economical ethanol from cellulose is 10 years down the road," says Prof Logan.
"There are substantial infrastructure issues to be addressed in using hydrogen gas, but the environmental and energy-conversion efficiency benefits for hydrogen as a transportation fuel makes it worth addressing and solving these issues," conclude the authors.
http://www.telegraph.co.uk/earth/main.jh...dro112.xml