There it is noted that “oil can also be degraded with the help of bacteria. It has been determined that more than one hundred species of thirty microbial genera are capable of using hydrocarbons as a method of subsistence. However, it has also been verified that there is a fraction of oil composed of resins and asphaltenes that are very complex molecules and for which most bacteria lack the tools to eliminate them completely. They do manage to partially degrade them to less toxic compounds or to compounds that can be incorporated as part of the soil material. Researchers in Germany have just identified and characterized bacteria that are capable of degrading some of the chemical components of polyurethane, which is the basis of many plastic products that are very difficult to recycle. The bacteria act at the level of the chemical bonds that form polyurethane plastics and can engulf small samples in about a week. ‘However, further experimentation is needed to define in what time and for what quantity an effective large-scale biodegradation process can be determined,’ Ecuadorian biotechnologist María José Cárdenas, a scientist at the Helmholtz Center for Environmental Research-UFZ in Leipzig, Germany, and co-author of the study, which was published in the latest edition of the journal Frontiers in Microbiology, tells ‘El Mercurio’. By 2021, global polyurethane production is expected to exceed 21 million tons. Because of its lightweight, insulating and flexible properties, it is used to manufacture everything from refrigerators and building envelopes to footwear and furniture. Until now it has been difficult to recycle or destroy, as most of these types of plastics are thermosetting, i.e. they do not melt when heated. Like polyurethane, there are many compounds whose final degradation is very slow or difficult. While there are decomposing organisms in nature, such as bacteria or fungi, humans have synthesized new carbon-based compounds such as plastics and petroleum. Since they were not present in nature before, bacteria cannot identify them as a food source,’ says Carolina Pizarro, project leader of the sustainability area at Fraunhofer Chile. To be able to ‘eat’ these structures, they need to produce new enzymes. These, which are specialized proteins present in all living things at the cellular level, are the equivalent of the knives and forks we humans use. They use them to reduce large molecules to smaller ones, Pizarro explains. Bacteria can sometimes produce new enzymes as a result of their need to survive. When they are in an environment with little organic matter, the decomposer organisms have had to evolve and adapt to these new food sources,’ says Pizarro. Thus, in landfills it is very likely to find bacteria that have adapted to extract carbon from sources that are more difficult to degrade, such as plastic. The strain of bacteria used in the German experiment, from the genus Pseudomonas, was isolated from the soil of a plastic waste landfill (most of it was waste that was fragmented into pieces) in the city of Leipzig, says Cárdenas.
In the deepest In the country, a team from the Center for Biotechnology and Bioengineering of the University of Chile (CeBiB), led by Juan Asenjo, winner of the National Prize for Applied Sciences, has found extremophile bacteria that can process arsenic in the inhospitable Atacama Desert. This is a toxic mineral by-product of the copper production process that today ends up in the tailings. They live on arsenic, some degrade it, others oxidize it and there are also those that feed on it,’ he explains. For the moment the tests have been done at a semi-experimental level, but now we have to take it to the field’, says the biotechnologist. At this stage of the research they are working with the company EcoMetales, which commissioned the project. Oil can also be degraded with the help of bacteria. It has been determined that more than one hundred species of thirty microbial genera are capable of using hydrocarbons as a method of subsistence. However, it has also been verified that there is a fraction of the oil composed of resins and asphaltenes that are very complex molecules and for which most bacteria lack the tools to eliminate them completely. They do manage to partially degrade them to less toxic compounds or compounds that can be incorporated as part of the soil material. Bacteria that ‘eat’ oil have been found in the most remote places on the planet. The last one to be discovered was detected in the Mariana Trench, at a depth of 10,000 meters.
