We rightly ponder the problem of future food security – in which plants, plant science, and plant scientists (in the broadest sense of that term) have a big part to play. However, just as pressing is concern over sufficiency of fresh – i.e. clean, disease-free, drinkable – water for those hungry humans.
Traditionally, one way of cleaning-up water that’s not fit for human consumption has been to use the moringa plant (Moringa oleifera) as a sort of water–purifier. Although that can be effective, it leaves behind high amounts of dissolved organic carbon (DOC), from the seeds that are used to clean the water. That DOC can act as a food source that permits and sustains the regrowth of bacteria after 24 hours. Thus, water cleaned by the traditional moringa technique is only drinkable for a limited period after treatment, i.e. it has a short ‘shelf-life’.
Taking that good idea and making it better is what Brittany Nordmark et al. have done. They show that proteins extracted from moringa seeds can be adsorbed to the surface of silica particles (‘sand’) where their positive charges act to attract both negatively-charged DOC and micro-organisms that contaminate the water. This f-sand* system thus has great potential as a relatively cheap – but much-improved – version of the traditional moringa water-purification method, which can be readily made (as this video shows) in places where it’s needed.
Well, one I see is that to ‘recharge’ the f-sand for reuse you need to wash out the adhered DOC and other undesirables. Presumably that means with clean water, whose supply is the problem in the first place. And, once reset, what do you do with this now-dirty water? But, there’s even more to moringa than just a natural water-purifier. So much more in fact that it has been called the Miracle Tree and is associated with both nutritional and properties, claims and benefits.
One tree that can help solve two of humanity’s greatest insecurities – getting enough of the right kind of food, and access to fresh water (and a third if you include its medicinal virtues…). What’s not to like?
*The ‘f’ of which term apparently stands for ‘antimicrobial functionalized’.
Hanjra, M. A., & Qureshi, M. E. (2010). Global water crisis and future food security in an era of climate change. Food Policy, 35(5), 365–377. https://doi.org/10.1016/j.foodpol.2010.05.006
Nordmark, B. A., Bechtel, T. M., Riley, J. K., Velegol, D., Velegol, S. B., Przybycien, T. M., & Tilton, R. D. (2018). Moringa oleifera Seed Protein Adsorption to Silica: Effects of Water Hardness, Fractionation, and Fatty Acid Extraction. Langmuir, 34(16), 4852–4860. https://doi.org/10.1021/acs.langmuir.8b00191
Jerri, H. A., Adolfsen, K. J., McCullough, L. R., Velegol, D., & Velegol, S. B. (2011). Antimicrobial Sand via Adsorption of Cationic Moringa oleifera Protein. Langmuir, 28(4), 2262–2268. https://doi.org/10.1021/la2038262