Bacteria As Fuel Cells?

KantIsDead writes "MIT's Tech Review is running an interview with Boston University Bioengineer Tim Gardner about the possibility of using bacteria to produce electricity. If fuel cells running off sugar are nearly here, alcohol-powered robots cannot be far." From the article: "While typical fuel cells use hydrogen as fuel, separating out electrons to create electricity, bacteria can use a wide variety of nutrients as fuel. Some species, such as Shewanella oneidensis and Rhodoferax ferrireducens, turn these nutrients directly into electrons. Indeed, scientists have already created experimental microbial fuel cells that can run off glucose and sewage. Although these microscopic organisms are remarkably efficient at producing energy, they don't make enough of it for practical applications."

Comments

I am more impressed

[Psionicist]

I am more impressed with that Montreal kid who did something similiar:

http://www.wired.com/news/technology/0,70882-0.htm l?tw=wn_index_12 A 16-year-old high school student has invented a new way of producing electricity by harnessing the brawny power of bacteria.

Kartik Madiraju, an 11th-grader from Montreal, was able to generate about half the voltage of a normal AA battery with a fifth of an ounce of naturally occurring magnetic bacteria. And the bacteria kept pumping current for 48 hours nonstop.

Can you smell the future?

[Itninja]

"alcohol-powered"
"glucose and sewage"

The future will be full of cars that only exaust water....and fueling stations brimming with switch-grass, corn-mash, stale beer, human feces, and the occasional Rhodoferax ferrireducens bateria. And I thought horses smelled bad....

Mutations

[yuckysocks]

Ok, assume that in 3 years we find just the right bacteria we need, and can have big
enough colonies of them to be useful. How do we stop them from just mutating into
non-viable types of their former selves and corrupting the colony? Sure they would
reproduce asexually and that would limit mutations compared to our dirty process
with gametes and zygotes, but that small rate of mutation will definitely be amplified
by the apparent fact that we'll need trillions of these bacteria to do anything large-scale.

IAABM (I am a biology major)

Re:Can someone explain?

[mishmash]

Take glucose - perhaps produced by a bacteria, or as also mentioned in the article available in the human blood stream and using a glucose oxidase enzyme - oxidise it - take electrons from it, you do this on the surface of an electrode at one end of the circuit - at the other end you have another electrode coated with another enzyme on that uses electrons to reduce someting - such as oxygen to water. With oxidation at one end and reduction at the other you have electrons flowing between them.

A paper describing doing this - but not using real human blood (why doesn't someone get on and do that - has the human race lost the spirit of development??)

Why use bacteria and not just enzymes? One answer maybe that enzymes need a specific substrate, some bacteria might be less choosey? An enzyme's only a catalyst why not use "chemical" catalysts like conventional fuel cells?

As for the biology major's worry that bacteria will lose the genetic modifications over time - yes that will happen - as the modifications that make them better for the purpose of making electricity will make them less good at simply multiplying - so loosing the extra function will give them an advantage which will be naturally selected for - so those bacteria will take over the culture. The solution's - you'll just not grow these things indefinatly - you'll have get a fresh culture of them regularly.