Breaking down herbicides in agriculture: farmers can easily pitch in

Researchers shed light on microbiological degradation of herbicide linuron

Dr. Başak Öztürk, Head of the Independent Junior Research Group „Microbial Biotechnology”

Farmer spraying herbicide (symbolic image) Source: pixabay/WFranz

Microbiologist Dr. Başak Öztürk of the Leibniz-Institute DSMZ-German Collection of Microorganisms and Cell Cultures in Braunschweig, Germany, identified at the time of her research stay at the Belgian Katholieke Universiteit Leuven together with her colleagues (headed by Prof. Dr. Dirk Springael) bacteria that break down the herbicide linuron. The scientists confirmed for the first time the role of Ramlibacter bacteria in the degradation of this plant protection agent in an on-farm purification system, and demonstrated the direct link between certain microorganisms and herbicide degradation. The results were recently published in the internationally renowned journal Environmental Science & Technology (DOI: 10.1021/acs.est.0c02124). 

Linuron breakdown in agriculture
Linuron is a selective herbicide that targets weeds by inhibiting photosynthesis. The EU banned the agent in 2018 due to its carcinogenic properties, but it is still used in some countries including the United States and Canada. To minimize the contamination of the ground water, many agricultural businesses in these countries have installed systems for water purification. These so-called ‘on-farm bio-purification systems’ (BPS) filter waste water collected during the cleaning process of farming equipment. The exact effect mechanism of these purification systems is not yet fully understood; what is known is that different bacteria are able to degrade the herbicides in the water. 

Three proteobacteria involved in BPS linuron breakdown
Scientists have long aimed to establish what kind of bacteria exactly are involved in the herbicide degradation. In the present study, Dr. Başak Öztürk and colleagues were able to show the involvement of bacteria of the genus Variovorax, Comamonadaceae and Ramlibacter in the breakdown of linuron. The latter were detected in a BPS-matrix for the first time ever. “The unique feature of our study is that we were able to show the direct link between herbicide breakdown and microorganisms responsible for this breakdown. Our experiments also established that in-situ, other microorganisms are responsible for the degradation of pollutants than previously thought from laboratory investigations”, summarizes Başak Öztürk. “Hopefully, clarifying the effect mechanism of these on-farm purification systems will now also convince German farmers of the usefulness of having their own little wastewater treatment plants. Setting up a BPS is neither cost intensive nor does it require a lot of space. And even if we do not employ linuron here in Germany, we do use other herbicides that may have a negative impact on the eco system.” Since 2018 Dr. Öztürk heads the Independent Junior Research Group „Microbial Biotechnology” at the Leibniz-Institute DSMZ, which focuses on the biodegradation of chemical compounds such as plant protection agents or plastics. 

Original publication:
Lerner H., Öztürk B., Dohrmann A., Thomas J., Marchal K., De Mot R., Dehaen W., Tebbe C., Springael D. Culture-independent Analysis of Linuron-Mineralizing Microbiota and Functions in On-Farm Biopurification Systems via DNA-Stable Isotope Probing: Comparison With Enrichment Culture. Environ Sci Technol. 2020 Jun 22. 
doi: 10.1021/acs.est.0c02124.  
Online ahead of print.

Press contact:
Sven-David Müller, Head of Public Relations, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures GmbH
Phone: ++49 (0)531/2616-300
Mail: Sven.David.Mueller(at)dsmz.de 

About the Leibniz Institute DSMZ
The Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures is the world's most diverse collection of biological resources (bacteria, archaea, protists, yeasts, fungi, bacteriophages, plant viruses, genomic bacterial DNA as well as human and animal cell lines). Microorganisms and cell cultures are collected, investigated and archived at the DSMZ. As an institution of the Leibniz Association, the DSMZ with its extensive scientific services and biological resources has been a global partner for research, science and industry since 1969. The DSMZ is the first registered collection in Europe (Regulation (EU) No. 511/2014) and certified according to the quality standard ISO 9001:2015. As a patent depository, it offers the only possibility in Germany to deposit biological material in accordance with the requirements of the Budapest Treaty. In addition to scientific services, research is the second pillar of the DSMZ. The institute, located on the Science Campus Braunschweig-Süd, accommodates more than 73,000 cultures and biomaterials and has 198 employees. www.dsmz.de  

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The Leibniz Association connects 96 independent research institutions that range in focus from the natural, engineering and environmental sciences via economics, spatial and social sciences to the humanities. Leibniz Institutes address issues of social, economic and ecological relevance. They conduct knowledge-driven and applied basic research, maintain scientific infrastructure and provide research-based services. The Leibniz Association identifies focus areas for knowledge transfer to policy-makers, academia, business and the public. Leibniz institutions collaborate intensively with universities – in the form of “Leibniz ScienceCampi” (thematic partnerships between university and non-university research institutes), for example – as well as with industry and other partners at home and abroad. They are subject to an independent evaluation procedure that is unparalleled in its transparency. Due to the importance of the institutions for the country as a whole, they are funded jointly by the Federation and the Länder, employing some 19,100 individuals, including 9,900 researchers. The entire budget of all the institutes is approximately 1,9 billion Euros. www.leibniz-gemeinschaft.de