BBC Focus

POTTY MOUTH

Microbes are often used to break down

wasteatsewagetreatmentplants.

Brocadia anammoxidanscan survive

without oxygen and loves nothing better

than to lunch on ammonia and nitrate in

human waste, producing a fuel that could,

theoretically, be used for space probes.

MICROBES

2 LIFE ON THE EDGE

These metal-munching microbes are just some

of the many tiny, super-powered organisms

living in extreme environments on Earth.

So-called ‘extremophiles’ can survive in

conditions that are hostile to other life. Take the

case of the Aquifex genus of bacteria, which

lives in hot springs in Yellowstone National

Park, where temperatures can reach a toasty

96°C. Or the salt-loving Halobacterium

halobium, which survives in sediments that are

10 times saltier than seawater. And then there is

‘The Daddy’ of all extremophiles – Conan the

Bacterium (aka Deinococcus radiodurans),

which can withstand acid baths, radiation doses

and huge extremes of temperatures.

But El-Naggar and his team are intent on

finding out more about the electron-eating

microbes in particular. They’ve already made

some astounding discoveries about their

anatomy. One day when filming Shewanella

under a microscope, it dawned on the team that

seemingly innocuous hair-like appendages were

vital to the electron transfer system. Electrons

were travelling along these ‘nanowires’ to the

mineral substrate. And El-Naggar believes that

when microbes are piled one on top of another

in sediment, the nanowires act a bit like straws,

so that the microbes at the bottom of the pile can

still transfer electrons.

Until a couple of years ago, the team studied

the microbes in a lab setting, because they

wa nted to use physical elect rodes in place of

the electron donors or acceptors that these

organisms interact with in nature.“Electrodes

give a huge advantage since they don’t get

consumed and allow physical interrogations of

the mechanisms by changing electric potentials

and so on,” says El-Naggar.

Recently, the team put their electrode-reactor

in the gold mine of the Sanford Underground PHOTOS: ALAMY, SCIENCE PHOTO LIBRARY ILLUSTRATION: JAMES OLSTEIN

A MARVELLOUS

MICROBIAL MENU

The strange eating habits of some

of the world’s most bizarre bugs

PLASTIC SURGERY

Around 300,000 tonnes of plastic swirl

around the planet’s oceans at any one

time. That is one giant plastic problem.

The good news is that a team of Japanese

scientists has discovered a bacterium

(Ideonella sakaiensis) that eats the

plastic found in most disposable bottles.

SLICK SOLUTION

In April 2010, the Deepwater Horizon oil

rig burst into flames, spilling almost five

million barrels of oil. Genetically

modified Alcanivorax borkumensis

microbes were brought in to help with

the clean-up operation by breaking

down the oil’s molecular structure.

NUKED!

In 2014, a team from the University of

Manchester discovered that various

microbes can degrade the organic

material found in nuclear waste. The

microbes use the waste as a source of

food and energy, and prevent radioactive

elements leaking into the environment.

SMARTY PANTS

Stinky underwear can be a problem on

any long journey – particularly if you’re

aboard the International Space Station.

The solution? In the 1990s, Russian

scientists tried using various bacteria to

degrade soiled underwear and turn the

resulting methane into biofuel.