Bacteria Can Eat and Digest Plastic

Can plastic be degraded by micro-organisms?

The research, led by Maaike Goudriaan, a PhD scholar at NIOZ, centered on the bacterium Rhodococcus ruber, which is found in a variety of habitats and may tolerate irritating environments. It is usually identified to type a “biofilm” on plastic present in nature.

Goudriaan’s experiment utilized a kind of plastic manufactured to hold a particular type of carbon – carbon-13 (¹³C). Within the laboratory, Goudriaan fed the plastic to R. ruber in a bottle of synthetic seawater after pre-treating it with a UV lamp. “The remedy with UV mild was essential as a result of we already know that daylight partially breaks down plastic into bite-sized chunks for micro organism,” she says.

Goudriaan discovered that CO₂ manufacturing occurred within the laboratory mannequin, from which she might measure the quantity of ¹³C-CO₂ and translate this to the quantity of plastic degraded. “That is the primary time we’ve confirmed on this manner that micro organism truly digest plastic into CO₂ and different molecules,” she states. It was already identified that the bacterium R. ruber can type a so-called biofilm on plastic in nature. It had additionally been measured that plastic disappears below that biofilm. “However now we’ve actually demonstrated that the micro organism truly digest the plastic.”

Graphical summary of the analysis technique. Picture: Maaike Goudriaan, NIOZ. Credit score: Maaike Goudriaan, NIOZ.

Goudriaan calculated that R. ruber can breakdown ~one % of the plastic annually. “That is in all probability an underestimate,” she emphasizes. “We solely measured the quantity of carbon-13 in CO₂, so not within the different breakdown merchandise of the plastic. There will definitely be ¹³C in a number of different molecules, nevertheless it’s exhausting to say what a part of that was damaged down by the UV mild and what half was digested by the micro organism.”

Prevention is healthier than cleansing up

Microbial digestion doesn’t characterize a complete resolution to the problem of plastic air pollution within the ocean, the researcher notes. However – it might be half of the answer. It might additionally present a solution as to why there may be a lot plastic thought of “lacking” within the ocean. “These experiments are primarily a proof-of-principle. I see it as one piece of the jigsaw, within the situation of the place all of the plastic that disappears into the oceans stays. In case you attempt to hint all our waste, lots of plastic is misplaced. Digestion by micro organism might presumably present a part of the reason,” Goudriaan says.     

The proof-of-principle research will must be adopted up with experiments testing whether or not micro organism within the “wild” may eat or digest plastic. To that finish, Goudriaan has performed pilot experiments with actual sea water and sediment obtained from the Wadden Sea ground. The primary outcomes trace that plastic might certainly even be degraded in nature. “A brand new PhD scholar must proceed that work. Finally, after all, you hope to calculate how a lot plastic within the oceans actually is degraded by micro organism. However a lot better than cleansing up, is prevention. And solely we people can try this,” she says.

This text is a rework of a press launch issued by the Royal Netherlands Institute for Sea Analysis. Materials has been edited for size and content material.

Reference: Goudriaan M. A steady isotope assay with ¹³C-labeled polyethylene to research plastic mineralization mediated by Rhodococcus ruber. Mar Pollut Bull. 2023. doi: 10.1016/j.marpolbul.2022.114369.