Institut Laue-Langevin

Revealing the secrets of seeds from a ‘miracle’ tree

Contaminated water causes more than 2 million deaths a year.  Water treatment usually involves chemical coagulants but some, for example aluminium salts, have health implications.  This has led to a search for alternative natural solutions and the most promising is from the Moringa tree.

The Moringa has been called a miracle tree. Native to northern India and found widely in Asia and Africa, it is a rich source of nutrients with a range of uses, from medicine and oil to pesticide and domestic cleaning agent.  The seeds, due to their natural coagulant properties, can purify water. Reported benefits include up to 99% reduction in cloudiness with a decrease in clay and bacteria content that rivals the efficiency of aluminium salts. 

Scientists, in order to develop future treatments from Moringa seeds, need to know exactly what processes take place during the purification. Thanks to the ILL, researchers are now a step closer to understanding how these seeds work. 

A team from Uppsala University in Sweden and the University of Botswana in Africa studied a protein extract from the Moringa oleifera tree seeds. During water purification the contaminant particles or impurities need to be combined and the protein is specifically known to act as a coagulating agent. The process of aggregation - or flocculation – then allows contaminants to be extracted.

“Our aim was to understand at a molecular level how the proteins from Moringa cause flocculation and how they are effective for water purification.” said Professor Adrian Rennie, from Uppsala University’s physics department.

The team used the D17 reflectometer instrument at ILL to examine the protein by neutron reflection and analyse how it binds to a surface (using silica as a model for mineral surfaces).  “The ILL has a very high intensity of neutrons,” said ILL scientist Robert Cubitt, “allowing even a single molecular layer to be detected.”

Previous studies, using different techniques, were not able to answer fundamental questions about the process or explain what controlled the interaction between water impurities and the protein.  The research at ILL, published in the American Chemical Society journal, Langmuir, took the understanding an important stage further.

“The paper identifies that the seed protein forms dense layers thicker than a single molecule even at very low concentrations,” explained Rennie.  “It suggests that the mechanism for aggregation of impurities is one that combines the strong tendency of the protein to bind to surfaces and the association of the protein molecules with each other.”

These findings not only extend previous studies, they provide information that could, in the long term, improve the water purification process with a non-toxic, biodegradable treatment.  “This is a nice example of research where not only is the subject scientifically fascinating,” said ILL’s Cubitt, “but it has a useful application which can affect the quality of peoples’ lives directly.”

For those whose lives could be saved from purified water, the ‘miracle’ Moringa tree would indeed live up to its name.

<cite>re.: Langmuir</cite>, 2010, 26 (6), pp 3902–3910