Science Research at UvA-VU: Earth Surface Science

Bacteria purify polluted groundwater

24 March 2015

Chemicals in drugs end up in our waste water and in the environment. Fortunately, some microorganisms may be able to break down these harmful substances. Exactly how these bacteria do this is being jointly investigated by the Earth Surface Science subgroup at the University of Amsterdam and by the Molecular Cell Physiology subgroup at VU University Amsterdam.

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Just imagine: if you go outside with a spade, each gram of earth you dig up will contain about one billion bacteria, representing at least ten thousand different species. Groundwater, too, contains millions of different species of bacteria. And these microorganisms have an important job to do: clearing up our waste (including chemical waste). This waste includes the drugs we use, which are transported into water (and groundwater) via urine. Dr Wilfred Röling (Molecular Cell Physiology, Faculty of Earth and Life Sciences, VU University Amsterdam) notes that 'Substances derived from anti-epileptic drugs are now present in groundwater at measurable levels.'

Breaking down

'The pharmaceutical industry is involved in the large-scale production of new chemicals for medicines. It is important to know whether the substances they use for this purpose are biodegradable. A given chemical might well be very useful in a drug, but if it enters the environment there is no way of getting rid of it. Dr Röling explains that “Before you know it, these substances will have entered the groundwater, and you’ll end up drinking them.'

He is collaborating in this study with Dr John Parsons (University of Amsterdam, Faculty of Science (FNWI) – Institute for Biodiversity and Ecosystem Dynamics). Together, they want to find out how quickly microorganisms can adapt to pollutants of this kind, and how effective they are at breaking them down.

Joining forces

To investigate such processes, samples taken at a waste water treatment company are examined in the lab. Wilfred Röling points out that 'here we are using a new technique, which involves adding water to the bacteria continuously, rather than adding a certain amount just once. That way, you are working with a system that more closely resembles the microorganisms’ natural habitat.'

The University of Amsterdam research team is focusing on changes in the substances contained in the drugs used, while the VU University Amsterdam team examines the microbiological aspects involved. They identify the species of microorganisms that are present and the pathways by which pollutants are broken down.

The collaboration between Wilfred Röling and John Parsons is based on a long-standing professional relationship. 'Our first collaborative research venture dates back to 2002, and we have kept in touch ever since. They have greater expertise in the field of environmental chemistry, while our strengths lie in the area of microbiology. I hope that our recent study will lead to further collaborative projects in the future.'

See also

In memoriam

To our great dismay our friend and colleague, Dr Wilfred Röling, passed away on 25 September 2015 at much too young an age, at a time when he was making discovery after discovery in ecosystems biology. The work Wilfred described in the interview is being continued much in his spirit, by his sad, but enthusiastic collegues and students. Hans V. Westerhoff (Molecular Cell Physiology, VU and Synthetic Systems Biology, UvA)

Published by  Faculty of Science