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c0lo [soylentnews.org] writes:

Many news sites report on the discovery of a plastic-eating bacterium which can break down PET. The original discovery was announced in the Science magazine [sciencemag.org].
After reading this piece of news on many sites, I considered the best details are presented on the Australian Broadcast Corporation site:

[...]a team of Japanese researchers, led by Dr Shosuke Yoshida from the Kyoto Institute of Technology, have discovered a new species of bacteria that produces a never-before-seen plastic-eating enzyme.

The researchers collected 250 debris samples — including soil and other sediments, wastewater and sludge — from a PET recycling plant and screened the microbial communities present in the samples [...]
"One sediment sample contained a distinct microbial consortium," Dr Kenji Miyamoto from Keio University, who was part of the study published today in Science, said. "The consortium contained a mixture of bacteria, yeast-like cells, and protozoa."
When they applied the microbes to a thin PET film, prominent pits formed on the film surface as it was consumed. It completely degraded after six weeks.

"We then successfully isolated a bacterium, Ideonella sakaiensis, from the group and found that this strain produces two enzymes," researchers said.
Further analysis showed the two enzymes — PETase and MHETase — could break down both PET and another compound called MHET — (mono 92-hydroxyethyl) terephthalic acid — which forms during the breakdown process.

[suggested break]

The researchers searched genomic databases to determine whether any other organisms shared the genes responsible for the enzymes that metabolise PET.

While they did not find any other species with the complete set of genes coding for PET metabolisation, they did find 92 micro-organisms that were able to code for MHETase, with 32 of those also able to code for other enzymes used in the PET metabolisation process.
The researchers say the volume of PET at the sample site, as well as the culturing of the microbial group during the experimental procedure, might have helped select for a bacterium that had obtained the necessary genes by swapping genes with other bacteria.

While the new discovery holds exciting possibilities for the harmless breakdown of environmentally-damaging plastics, Dr Miyamoto said that it was not as simple as unleashing armies of PET-metabolising bacteria into landfills to break down waste plastic.
"Because of its crystal structure, the rate of degradation is very slow. However, after heat-treatment at 260 degrees, the crystal structure breaks down, allowing these micro-organisms to easily decompose the plastic," he said.

Original Submission