{"id":54972,"date":"2024-10-10T00:06:52","date_gmt":"2024-10-10T00:06:52","guid":{"rendered":"https:\/\/peymantaeidi.net\/stem-cell\/?p=54972"},"modified":"2024-10-10T00:35:48","modified_gmt":"2024-10-10T00:35:48","slug":"plastic-eating-bacteria-discovered-in-urban-waterways","status":"publish","type":"post","link":"https:\/\/peymantaeidi.net\/stem-cell\/2024\/10\/10\/plastic-eating-bacteria-discovered-in-urban-waterways\/","title":{"rendered":"Plastic-Eating Bacteria Discovered in Urban Waterways"},"content":{"rendered":"
<\/a>
Comamonas bacteria live in wastewater, where they break down plastic waste for food. Credit: Ludmilla Aristilde\/Northwestern University<\/figcaption><\/figure>\n

This discovery could pave the way for bioengineered solutions to tackle plastic waste cleanup.<\/h3>\n

Researchers have long observed that a common family of environmental bacteria, Comamonadacae<\/em>, grow on plastics littered throughout urban rivers and wastewater systems. But what, exactly, these Comamonas <\/em>bacteria are doing has remained a mystery.<\/p>\n

Now, Northwestern University<\/p>\n

Established in 1851, Northwestern University (NU) is a private research university based in Evanston, Illinois, United States. Northwestern is known for its McCormick School of Engineering and Applied Science, Kellogg School of Management, Feinberg School of Medicine, Pritzker School of Law, Bienen School of Music, and Medill School of Journalism.&nbsp;<\/div>\n

” data-gt-translate-attributes=”[{"attribute":"data-cmtooltip", "format":"html"}]” tabindex=”0″ role=”link”>Northwestern University<\/span><\/a>-led researchers have discovered how cells of a Comamonas<\/em> bacterium are breaking down plastic for food. First, they chew the plastic into small pieces, called nanoplastics. Then, they secrete a specialized enzyme that breaks down the plastic even further. Finally, the bacteria use a ring of carbon atoms from the plastic as a food source, the researchers found.<\/p>\n

The discovery opens new possibilities for developing bacteria-based engineering solutions to help clean up difficult-to-remove plastic waste, which pollutes drinking water and harms wildlife.<\/p>\n

The study will be published on Thursday (Oct. 3) in the journal Environmental Science & Technology.<\/em><\/p>\n

\u201cWe have systematically shown, for the first time, that a wastewater bacterium can take a starting plastic material, deteriorate it, fragment it, break it down, and use it as a source of carbon,\u201d said Northwestern\u2019s Ludmilla Aristilde, who led the study. \u201cIt is amazing that this bacterium can perform that entire process, and we identified a key enzyme responsible for breaking down the plastic materials. This could be optimized and exploited to help get rid of plastics in the environment.\u201d<\/p>\n

An expert in the dynamics of organics in environmental processes, Aristilde is an associate professor of environmental engineering at Northwestern\u2019s McCormick School of Engineering. She also is a member of the Center for Synthetic Biology, International Institute for Nanotechnology and Paula M. Trienens Institute for Sustainability and Energy. The study\u2019s co-first authors are Rebecca Wilkes, a former Ph.D. student in Aristilde\u2019s lab, and Nanqing Zhou, a current postdoctoral associate in Aristilde\u2019s lab. Several former graduate and undergraduate researchers from the Aristilde Lab also contributed to the work.<\/p>\n

The pollution problem<\/h4>\n

The new study builds on previous research from Aristilde\u2019s team<\/a>, which unraveled the mechanisms that enable Comamonas testosteri<\/em> to metabolize simple carbons generated from broken down plants and plastics. In the new research, Aristilde and her team again looked to C. testosteroni<\/em>, which grows on polyethylene terephthalate (PET), a type of plastic commonly used in food packaging and beverage bottles. Because it does not break down easily, PET is a major contributor to plastic pollution.<\/p>\n

\u201cIt\u2019s important to note that PET plastics represent 12% of total global plastics usage,\u201d Aristilde said. \u201cAnd it accounts for up to 50% of microplastics in wastewaters.\u201d<\/p>\n

Innate ability to degrade plastics<\/h4>\n

To better understand how C. testosteroni <\/em>interacts with and feeds on the plastic, Aristilde and her team used multiple theoretical and experimental approaches. First, they took bacterium \u2014 isolated from wastewater \u2014 and grew it on PET films and pellets. Then, they used advanced microscopy to observe how the surface of the plastic material changed over time. Next, they examined the water around the bacteria, searching for evidence of plastic broken down into smaller nano-sized pieces. And, finally, the researchers looked inside the bacteria to pinpoint tools the bacteria used to help degrade the PET.<\/p>\n

\u201cIn the presence of the bacterium, the microplastics were broken down into tiny nanoparticles of plastics,\u201d Aristilde said. \u201cWe found that the wastewater bacterium has an innate ability to degrade plastic all the way down to monomers, small building blocks which join together to form polymers. These small units are a bioavailable source of carbon that bacteria can use for growth.\u201d<\/p>\n

After confirming that C. testosteroni<\/em>, indeed, can break down plastics, Aristilde next wanted to learn how. Through omics techniques that can measure all enzymes inside the cell, her team discovered one specific enzyme the bacterium expressed when exposed to PET plastics. To further explore this enzyme\u2019s role, Aristilde asked collaborators at Oak Ridge National Laboratory in Tennessee to prepare bacterial cells without the abilities to express the enzyme. Remarkably, without that enzyme, the bacteria\u2019s ability to degrade plastic was lost or significantly diminished.<\/p>\n

How plastics change in water<\/h4>\n

Although Aristilde imagines this discovery potentially could be harnessed for environmental solutions, she also says this new knowledge can help people better understand how plastics evolve in wastewater.<\/p>\n

\u201cWastewater is a huge reservoir of microplastics and nanoplastics,\u201d Aristilde said. \u201cMost people think nanoplastics enter wastewater treatment plants as nanoplastics. But we\u2019re showing that nanoplastics can be formed during wastewater treatment through microbial activity. That\u2019s something we need to pay attention to as our society tries to understand the behavior of plastics throughout its journey from wastewater to receiving rivers and lakes.\u201d<\/p>\n

Reference: \u201cMechanisms of Polyethylene Terephthalate Pellet Fragmentation into Nanoplastics and Assimilable Carbons by Wastewater Comamonas\u201d by Rebecca A. Wilkes, Nanqing Zhou, Austin L. Carroll, Ojaswi Aryal, Kelly P. Teitel, Rebecca S. Wilson, Lichun Zhang, Arushi Kapoor, Edgar Castaneda, Adam M. Guss, Jacob R. Waldbauer and Ludmilla Aristilde, 3 October 2024, Environmental Science & Technology<\/i>.
DOI: 10.1021\/acs.est.4c06645<\/a><\/p>\n

The study was supported by the National Science Foundation (award number CHE-2109097).<\/p>\n","protected":false},"excerpt":{"rendered":"

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