{"id":589587,"date":"2026-09-04T05:16:37","date_gmt":"2026-09-04T05:16:37","guid":{"rendered":"https:\/\/www.newsbeep.com\/nz\/589587\/"},"modified":"2026-09-04T05:16:37","modified_gmt":"2026-09-04T05:16:37","slug":"an-enzyme-that-offers-hope-novel-plastic-degrading-enzyme-discovered-in-bacteria","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/nz\/589587\/","title":{"rendered":"An Enzyme That Offers Hope: Novel Plastic-Degrading Enzyme Discovered in Bacteria"},"content":{"rendered":"

Researchers at the University of Konstanz have discovered a new \u201cPac-Man enzyme\u201d in bacteria<\/a> that can break down polyester<\/a> plastic as well as antibiotics<\/a> such as penicillin. This lays a new foundation for research on microbial plastic degradation as well as for our understanding of the spread of antibiotic resistance<\/a> in the environment, including its evolution.<\/p>\n

Huge amounts of plastic waste accumulate in the oceans in so-called\u201cGreat Garbage Patches\u201dand spell disaster for the organisms living there. This is because the synthetic plastic polymers used today can be broken down biologically\u2014that is, by microorganisms\u2014only very slowly. Instead, the physical fragmentation of the materials leads to micro- and nanoplastics. However, microbes colonize the plastic waste found in the environment, forming a biofilm in a unique microbial habitat that researchers refer to as the \u201cplastosphere.\u201d<\/p>\n

A newly discovered enzyme in these bacteria raises hopes that microorganisms could specialize in breaking down plastic faster than expected. A research team at the University of Konstanz discovered this previously unknown enzyme, which not only breaks down certain types of polyester and bioplastics but also confers antibiotic resistance to the bacteria. Due to its structure, which features a wide-open active site, the researchers have dubbed this \u201cplastic-eater\u201d the \u201cPac-Man enzyme.\u201d Humans can support the breakdown of plastic in the environment by, ideally, using only bioplastics that can be broken down by microorganisms.<\/p>\n

The Research Project<\/p>\n

In their research project, Konstanz biologists Harry Lerner and David Schleheck investigated the complete microbial degradation of bioplastics. At the same time, they studied the composition and the entire genetic information (the metagenome) of the microbial community involved. The study used bioplastic materials developed by the group led by chemist Stefan Mecking\u2014known as long-chain aliphatic polyesters (LCAP). Their joint study has now been published in*The ISME Journal *.<\/p>\n

How did the research team conduct their study? \u201cWe buried small pieces of LCAP bioplastic film in the top layer of humus in the forest of the university\u2019s botanical garden, about ten centimeters deep,\u201d explains Harry Lerner. \u201cThis is the layer where the degradation of cellulose and other natural polymers, such as cutin\u2014a plant-based polyester\u2014takes place.\u201d At the same time, the team mixed a powder of the bioplastic into samples of the same forest soil in the laboratory. The samples in the forest were left undisturbed for an entire year, while for the samples in the lab, the degradation of the materials\u2014as measured byCO\u2082 production and thus microbial respiration\u2014was tracked in great detail, also over the course of an entire year. \u201cCellulose, other types of bioplastics such as PHBV and PCL, as well as hard plastic (HDPE) and untreated soil as a negative control, served as references in the laboratory. We were able to demonstrate complete degradation of all bioplastic materials within about 250 to 330 days, of cellulose after about 80 days, while practically nothing happened with HDPE,\u201d Lerner explains.<\/p>\n

An Unexpected Discovery<\/p>\n

A surprise awaited the researchers when they examined the films collected from the forest floor: Under the electron microscope, it became apparent that microscopic holes had formed in the film. And these holes were exactly the size and shape of individual bacterial cells. \u201cWe hypothesized that bacteria might be coated with plastic depolymerases firmly anchored to their cell surfaces, effectively digesting their way into the material and thus sinking into the film. In the process, they leave behind such tiny holes,\u201d explains Lerner.<\/p>\n

To find out which microbes accumulate in the soil samples during the degradation of the bioplastic materials and which enzymes are responsible for breaking down the materials, Harry Lerner extracted the total DNA from the soil microbial community, sequenced it, and analyzed the large amounts of data with great patience and care. The microbiologists found a gene that had become highly enriched in the forest soil containing LCAP. It encodes a so-called esterase enzyme that possesses both a secretion signal\u2014a kind of address label for export outside the cell, so to speak\u2014and a so-called membrane anchor (lipid anchor). The latter enables the enzyme to bind firmly to the cell surface. The \u201cPac-Man enzyme\u201d had been found.<\/p>\n

The enzyme revealed yet another surprise: \u201cIt shows a structural similarity not only to esterases but also to beta-lactamases\u2014that is, bacterial enzymes capable of cleaving the beta-lactam ring of certain antibiotics, such as penicillin, thereby conferring antibiotic resistance on bacteria,\u201d said Lerner. And indeed, the researchers were able to demonstrate the enzyme\u2019s dual biochemical function\u2014breaking down polyesters into monomers on the one hand and cleaving penicillin on the other\u2014in the laboratory as well.<\/p>\n

A Paradigm Shift in the Plastosphere?<\/p>\n

\u201cIn our environment, the plastosphere is a new habitat,\u201d emphasizes Schleheck. \u201cHumans have only been introducing plastic into the environment in significant quantities for about 50 to 75 years. Since then, it has essentially been available to microbial communities\u2014such as bacteria, yeasts, and fungi\u2014as an additional carbon and energy substrate for their growth. By \u2018in theory,\u2019 I mean that they would certainly like to use the plastic as a growth substrate\u2014but they can\u2019t, because the materials are practically indigestible for microbial metabolism and are therefore hardly broken down at all.\u201d<\/p>\n

At least until now. The \u201cPac-Man enzyme\u201d could now signal a turning point, indicating that some microorganisms are now specializing entirely in plastic degradation. \u201cThat gives me personal hope, because it looks as though bacteria might be able to specialize in breaking down polyester plastics more quickly than expected. For solving the problem of plastic in the environment, this means that we humans must meet the microbes halfway and, ideally, use only polymers in the future that possess such biochemical weak points as the hydrolyzable ester bonds in polyesters\u2014for example, in LCAP or other types of bioplastics,\u201d says Schleheck.<\/p>\n","protected":false},"excerpt":{"rendered":"Researchers at the University of Konstanz have discovered a new \u201cPac-Man enzyme\u201d in bacteria that can break down…\n","protected":false},"author":2,"featured_media":589588,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[111,139,69,147],"class_list":["post-589587","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-new-zealand","tag-newzealand","tag-nz","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/589587","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=589587"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/589587\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/589588"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=589587"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=589587"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=589587"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}