Researchers from Tel Aviv University, Migal Research Institute and Tel Hai College have developed a biochemical process that combines enzymes and natural bacteria to break down the toxic pesticide paraoxon into harmless substances.
A joint study led by researchers from Tel Aviv University and Migel Research Institute and Tel Hai College, led to the development of an innovative and environmentally friendly process for breaking down polluting substances that cause damage to the environment and humans. The study focused on the toxic pesticide paraoxon (a type of organic phosphorus), which is still used in developing countries, pollutes the soil and may enter water reservoirs and groundwater. In the new process, the material is broken down into harmless substances through a combination of enzymes and natural bacteria. According to the researchers, the platform they developed can be adapted to many types of toxic and polluting substances. "We believe that in the future it will help clean up soil and water contamination - a major challenge of the modern world."
The research was led by Prof. Lehi Adler-Abramovich From the Morris and Gabriela Goldschlager School of Dentistry at Tel Aviv University, and Dr. Livnat Afriat-Gourno from the MiGl Research Institute and Tel Hai College, and in collaboration between the laboratory teams that include doctoral student Yoav Dan, David Gurevich, Dr. Ofir Gershoni and Francesca Netti. The research was funded by by the Ministry of Science and the Ministry of Landscaping, and published in the journal ACS Applied Materials & Interfaces.
A new method for breaking down toxic pesticides
Prof. Adler-Abramovitz explains: "Environmental pollutants, including pesticides, are currently a serious problem all over the world. They pollute the soil, and worse, in the absence of adequate treatment, they may reach agricultural land, water reservoirs and groundwater and contaminate our food and vital water sources In this research, we sought to develop an efficient and environmentally friendly method that would break down polluting substances into harmless products."
The research team chose to focus on a pesticide called paraoxon - a type of toxic organic phosphorus that damages the nervous system, and is currently used mainly in developing countries. In the first stage, they wanted to use the enzyme MPH (methyl parathion hydrolase), which belongs to the family of phosphotriesterase enzymes being studied in the Apriet-Journo laboratory, due to their ability to break down the insecticide with very high efficiency, but the enzymatic breakdown product is still considered a toxic substance. Dr. Apriat-Gourno explains, "In order to enable the breakdown of the insecticide into non-toxic substances, we needed a complex challenge, which combines enzymes and bacteria from the environment capable of breaking down the toxic by-products."
The researchers explain that the MPH enzyme breaks down the pesticide into two byproducts, but one of them, PNP (paranitrophenol), is also considered an environmental pollutant, even if less toxic. To also break down the PNP into harmless products, they added Arthrobacter bacteria to the enzyme system. Dr. Livnat Apriat-Gourno explains: "From previous studies it emerged that these bacteria live in soil contaminated by pesticides, and can effectively break them down into non-toxic substances. In our study, the bacteria decomposed the PNP remaining after paraoxon decomposition, so that in the end all the products of the process are non-toxic and environmentally friendly."
Nanocapsules that will extend the shelf life of enzymes
"Enzymes, which are proteins, are very sensitive to any change in their environment, so their shelf life is often short, which harms their ability to be used in the various industries. In our research, we saw that MPH completely loses its activity about 20 days after the date of production. In order to achieve a more durable product, We have developed dedicated peptide nanocapsules that extend its shelf life, and are made of a biodegradable material that will eventually break down in nature They suggested that inside the capsules the enzyme maintains its activity for a relatively long time: about 50% of the activity is maintained even after four and a half months (132 days)," explains Yoav Dan.
"In our research, we developed an integrated system of enzymes protected within nanostructures and enables their combination with natural bacterial culture. This system allows the breakdown of a toxic pesticide into harmless products. It is important to note that the new method uses only natural substances - enzymes, peptides and bacteria, Without genetically engineered materials whose future impact on the environment is unknown.Furthermore, our system is flexible, and capable enzymes and bacteria can be incorporated into it various, which will break down a wide variety of polluting substances. We believe that our method can serve as a basis for developing friendly and effective products for cleaning contaminated water or land areas - for the environment, health, and agriculture around the world," concludes Prof. Adler-Abramovich.
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