The Agar Tweet Twitch

(January 15th, 2016) Recently, Nature News issued a warning: there’s not enough seaweed for everyone. Microbiologists should, thus, stock up on their agar, as the dwindling algae harvest is about to imperil the culturing of lab microbes. How worried should researchers be?

It all started with a tweet by Adam Roberts, a microbiologist at the University College London, who called attention to a possible agar shortage. At the end of October, he received a letter from Thermo Fisher, informing him about the suspense of some of their raw agar products until 2016. As Roberts’ lab is a large-scale consumer of agar for investigating antimicrobial compounds in bacteria, a shortage of agar would be a “bloody nightmare”, he told Nature News. Luckily, Roberts was able to resource the precious substance from other suppliers. This prevented him, he wrote in an email to Lab Times, from “rationing agar and prioritising some experiments over others” - something he had feared earlier.

So why did Thermo Fisher decide to stop selling two of their high quality agar products? According to their letter, the simple reason is: shortage of the Gelidium seaweed species, the raw material that is used to produce agar. These red algae prefer rocky substrates with steep slopes, and are more abundant in turbulent and wave-exposed areas. They form dense underwater mats and are found in every geographic region in the world, except for the Arctic and Antarctic, as it grows best at 15-20 °C. Prior to the Second World War, Japan was the main source of the world’s agar but industrialisation led to a depletion of the natural stocks. Overexploitation also caused a harvest collapse during the 2000s in Indonesia, Portugal, Japan and Spain. This was, however, compensated by increased exploitation in Morocco, nowadays the world’s major supplier.

Because of fear of overexploitation and thus conservation purposes, the Moroccan government issued an order in 2010, limiting both the harvesting and the export of seaweed but only began to enforce these trade limits last year. Until now, the European Commission has had no success in convincing the Moroccan government that these export restrictions violate its free-trade agreement with European Union countries. An easy way to solve the shortage crisis would be to grow the seaweed in huge containers on an industrial scale but, to-date, cultivation of Gelidium species in tanks has not proven economically viable.

Chemically, the two components in agar are agarose (long chains of sugar molecules - the gelling component) and agaropectin (a heterogeneous mixture of smaller molecules with low gelling ability). It is two types of purified, high quality, raw agar products that Thermo Fisher has currently stopped selling, to give priority to the more-popular products that contain a mixture of agar and growth nutrients. So has this news caused unnecessary panic in the scientific world?

An enquiry in a few microbiology labs in different European countries brought to light that PhD students are not aware of any agar scarcity. The same is true for lab supply companies. Sigma-Aldrich explains that they have not noticed much of a shortage angst either, except for an increase in the price. Such an increase is, however, normal in the cold season. Also Dutch lab supplier, Duchefa Biochemie, does not experience any problems in purchasing their agar products. They attribute it to good relations with their suppliers. A company spokesperson verifies that prices have increased somewhat but not by a shocking amount and that their customers are not affected. And lastly, the Material Centre of the University of Zurich informs us that their suppliers last increased their prices in 2013 and that they have no difficulties in delivering the products.

So, what is the story, in short? Keep calm and carry on using #agar.

Hedwig Ens

Photo: Now Foods (seen on

Last Changes: 05.02.2016

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