Phosphorus is needed for growing crops, but is also a finite mineral resource. The increasing interest for microalgae production means that yet another activity will compete for available phosphorus. BioBUF researcher Joshua Mayers, presented a possible solution at the Algae Biomass Summit in Washington DC.

The UN has listed phosphorus as a resource to keep eye on since worldwide phosphorus deposits are predicted to last only another 300 years at current rates of usage. Several of the main phosphorus deposits are also found in geopolitically unstable areas, and prices vary substantially depending on political events in these areas. Syria has previously been the main supplier to the phosphorus used in Europe, but export has been severely affected. For microalgae producers that strive to make their business economically viable, the cost for the nutrients (including phosphorus) in the growth media is significant.

In addition to the risk of declining natural resources, phosphorus is together with nitrogen causing eutrophication of lakes and seas, as seen in the Baltic Sea, where the nutrients from arable land in the surrounding countries are leached into the water. These two issues combined mean that recycling the phosphorus we use will be critical in the future, predicts Joshua Mayers.

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At the Algae Biomass Summit, the world’s largest algae conference, Joshua has presented opportunities on how to reduce the phosphorus demand of algae cultivation. In a series of experiments, he has compared the growth of Nannochloropsis, a popular marine algae, when cultivated in ordinary medium compared to when cultivated in wastewater from a food waste digestion plant. The results show the same growth and the same chemical composition were achieved regardless of nutrient source. By carefully controlling the medium composition and by using wastewater, Joshua Mayers succeeded in reducing the demand of phosphorus by 67 percent and the demand of nitrogen with 100 percent! At the same time, the cost of the growth medium was lowered by over 80 percent.

Many questions were asked after the presentation, and Joshua Mayers thinks that it seemed like many in the audience got a new perspective on the question.

– Many hadn’t realized the extent of the problem when it comes to our future demand of phosphorus, and how much a large-scale production will affect the global market for nutrients, he comments.

The presentation, titled “The Approaching Global Phosphorous Crisis and Microalgal Biotechnology: Perspectives on a Growing Problem and Strategies for Effective Usage” by Joshua Mayers, Eva Albers and Kevin Flynn, was given at the Algae Biomass Summit in Washington DC, September 29th to October 2nd, 2015.