Plastic-eating bacteria discovered in recycling plant

By Eva Botkin-Kowacki

Plastic is everywhere around us. We drink out of plastic cups, buy disposable water bottles, unwrap new electronics from plastic packaging, take home plastic shopping bags, and even wear plastic in polyester fabrics.

Some 311 million tons of plastic is produced across the globe annually, and just 10 percent makes it back to a recycling plant. The rest ends up in landfills, or as litter on land or in the ocean, where it remains for decades and longer.

As for the plastic that has been recycled, it has given rise to an unintended side effect: A team of scientists searching through sediments at a plastic bottle recycling plant in Osaka, Japan have found a strain of bacteria that has evolved to consume the most common type of plastic.

Ideonella sakaiensis 201-F6 can degrade poly (ethylene terephthalate), commonly called PET or PETE, in as little as six weeks, they report in a new paper published Thursday in the journal Science.

Common uses of PET include polyester fibers, disposable bottles, and food containers. The last two are typically labelled with a No. 1 inside a recycling symbol.

But this new paper doesn’t mean you should ditch your reusable water bottles in favor of a tray of disposable ones, or that we’re going to inject this bacteria into landfills tomorrow. This study simply evaluated if the bacteria in question could degrade PET and was conducted under laboratory conditions.

“We hope this bacterium could be applied to solve the severe problems by the wasted PET materials in nature,” Kohei Oda, one of the study authors, tells The Christian Science Monitor in an email. But “this is just the initiation for application.” More research has to be done in order to make this a practical solution to plastic pollution.

But could this sort of fix work in theory?

“[Plastics] have been engineered for cost and for durability, or longevity,” says Giora Proskurowski, an oceanographer at the University of Washington who studies plastic debris in the ocean but was not part of this study, in a phone interview with the Monitor. But he’s hopeful that this research could yield further studies and technologies to mitigate the problem.

The durability of plastic isn’t the only challenge this potential fix faces. Microbes are like teenagers, Christopher Reddy, a senior scientist at Woods Hole Oceanographic Institution who studies environmental pollution and was not part of this study, explains in an interview with the Monitor.

“You can tell them to clean the garage over the weekend but they’re going to do it on their own timescale, they’re going to do it when they want, they’re going to pick the easiest thing to do and they’re likely going to leave you more frustrated than you think,” he explains the metaphor. Similarly, you can’t rely on microbes to break down compounds. “Don’t rely on microbes to clean the environment.”

Dr. Reddy says that has a lot to do with the environment outside the lab. In the experiment, he says, the researchers controlled the situation so the bacteria ate the plastic, but in nature, they would have many options for food.

Also, if I. sakaiensis 201-F6 were to be applied, it would likely only help plastic pollution on land. PET particles are denser than water, so they tend to sink down into the sediment. The trillions of tons of plastic particles amassing in the oceans are other types of plastics, types for which this bacteria probably lacks an appetite. Also, Dr. Proskurowski says, marine organisms have evolved to withstand the saltwater and sunlight that sediment-dwelling organisms might not.

Still, perhaps this bacteria could be harnessed to accelerate degradation of plastics that make it to a landfill, he says.

But this study does show that “the environment is evolving and you get the microbes evolving along with that as well,” Proskurowski says. “These are evolving systems.”

Neither Proskurowski nor Reddy were surprised that the researchers found an organism that can consume PET.

“I’m surprised it’s taken this long. I’ve been waiting for results like this,” Proskurowski says.

“Nature is incredibly wily, microbes are incredibly wily,” Reddy says. “Microbes are very good eaters.”

This is not the first time researchers have found an organism that will eat trashed plastic. Last year engineers at Stanford University found a mealworm that can eat styrofoam. And in that case, it was not the animal’s digestion that broke down the styrofoam, but bacteria it its gut.

http://www.csmonitor.com/Science/2016/0310/Researchers-discover-plastic-eating-bacteria-in-recycling-plant

Risk of American ‘megadroughts’ for decades, NASA warns

There is no precedent in contemporary weather records for the kinds of droughts the country’s West will face, if greenhouse gas emissions stay on course, a NASA study said.

No precedent even in the past 1,000 years.

The feared droughts would cover most of the western half of the United States — the Central Plains and the Southwest.

Those regions have suffered severe drought in recent years. But it doesn’t compare in the slightest to the ‘megadroughts’ likely to hit them before the century is over due to global warming.
These will be epochal, worthy of a chapter in Earth’s natural history.

Even if emissions drop moderately, droughts in those regions will get much worse than they are now, NASA said.

The space agency’s study conjures visions of the sun scorching cracked earth that is baked dry of moisture for feet below the surface, across vast landscapes, for decades. Great lake reservoirs could dwindle to ponds, leaving cities to ration water to residents who haven’t fled east.

“Our projections for what we are seeing is that, with climate change, many of these types of droughts will likely last for 20, 30, even 40 years,” said NASA climate scientist Ben Cook.

That’s worse and longer than the historic Dust Bowl of the 1930s, when “black blizzards” — towering, blustery dust walls — buried Southern Plains homes, buggies and barns in dirt dunes.

It lasted about 10 years. Though long, it was within the framework of a contemporary natural drought.

To find something almost as extreme as what looms, one must go back to Medieval times.

Nestled in the shade of Southwestern mountain rock, earthen Ancestral Pueblo housing offers a foreshadowing. The tight, lively villages emptied out in the 13th century’s Great Drought that lasted more than 30 years.

No water. No crops. Starvation drove populations out to the east and south.

If NASA’s worst case scenario plays out, what’s to come could be worse.

Its computations are based on greenhouse gas emissions continuing on their current course. And they produce an 80% chance of at least one drought that could last for decades.

One “even exceeding the duration of the long term intense ‘megadroughts’ that characterized the really arid time period known as the Medieval Climate Anomaly,” Cook said.

That was a period of heightened global temperatures that lasted from about 1100 to 1300 — when those Ancestral Pueblos dispersed. Global average temperatures are already higher now than they were then, the study said.

The NASA team’s study was very data heavy.

It examined past wet and dry periods using tree rings going back 1,000 years and compared them with soil moisture from 17 climate models, NASA said in the study published in Science Advances.

Scientists used super computers to calculate the models forward along the lines of human induced global warming scenarios. The models all showed a much drier planet.

Some Southwestern areas that are currently drought-stricken are filling up with more people, creating more demand for water while reservoirs are already strained.

The predicted megadroughts will wrack water supplies much harder, NASA Goddard Space Flight Center said.

“These droughts really represent events that nobody in the history of the United States has ever had to deal with,” Cook said.

Compared with the last millennium, the dryness will be unprecedented. Adapting to it will be tough.

http://www.cnn.com/2015/02/14/us/nasa-study-western-megadrought/index.html

NASA develops biodegradable drone

By Peter Shadbolt for CNN

A bio-drone that dissolves after use leaving no trace it ever existed may sound like the stuff of a James Bond film, but NASA and a team of researchers are actually building one.

Made from a substance that combines mushroom fibers and cloned paper wasp spit, the drone might resemble a propeller-powered egg carton, but its designers say it has the ability to fly into environmentally sensitive areas and leave almost no trace.

Lynn Rothschild, the NASA developer guiding students from Stanford-Brown-Spelman working on the project, says the drone could be made to disappear simply by ditching it into a stream or puddle.

She said her interest in unmanned aerial vehicles was sparked by work on environmentally sensitive areas in her Earth Science group at NASA.

“Periodically, UAVs get lost — for example on coral reefs or in other sensitive habitats,” she said in an interview with the project team.

“As I started to hear about this, I thought, ‘Well, wouldn’t it be useful if the UAV was biodegradable, so if it crashed somewhere that was sensitive, it wouldn’t matter if it dissolved.”

The mushroom-like substance known as mycelium, which makes up the chassis of the drone, is being hailed as the new plastic — a plastic that has the advantage of degrading quickly.

The team grew cellulose “leather” to coat the fungal body of the flying craft and then covered the sheets with proteins sourced from the saliva of paper wasps — a water resistant material that the insects use to cover their nests.

The circuits are printed from silver nanoparticle ink in an effort to make the machine as biodegradable as possible.

Despite a heavy preponderance of biological parts, the team said the project had its limits.

“There are definitely parts that can’t be replaced by biology, ” said Stanford University’s Raman Nelakanti.

At its first short flight at the International Genetically Engineered Machine competition in Boston, the team used a standard battery, motor and propellers to fly the drone.

Nevertheless, the team is working on making other parts biodegradable and is studying how to build its sensors from modified E. coli bacteria, the bacteria most commonly found in the intestines of humans and animals.

The team said that ultimately the drone could be sent into areas where it might not be expected to return such as wildfires or nuclear accidents, sending data and never coming back.

While the parts degrade naturally, the team also experimented with enzymes that would help the drone self-destruct, breaking it down further on impact.

Creating a drone that does not infect the environment has been another challenge for the team.

“If you have living organisms acting as biosensors and the plane crashes, there certainly could be problems as the plane interacts with the environment,” Rothschild said.

“Hopefully people could think of this in advance, and design such that this never becomes a problem.

“For example, on crashing, the cells might die. Or the cells could be attenuated. There are all sorts of other processes to keep them from contaminating the environment. But that, to me, is the largest concern with a biological UAV – having living things on the UAV.”

http://www.cnn.com/2014/12/10/tech/innovation/nasa-dissolving-drone/index.html?hpt=hp_c4