Could your burger one day come with a plankton patty? Alison Ballance visits the Cawthron Institute's collection of more than 750 different strains of microalgae, where scientists are investigating these teeny organisms for new food ingredients and powerful painkillers.

Imagine a future where your burger comes with a plankton patty.

Or where you are prepped for a hospital operation with an algal anaesthetic.

If Cawthron Institute researchers have their way, this microalgae-themed future for food and pharmaceuticals could be just around the corner.

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The Cawthron Institute research is based on a culture collection of microalgae, also known as phytoplankton. The collection goes back more than three decades, and now contains more than 750 isolates or different strains of microalgae, collected from New Zealand, Antarctica and the Pacific. It includes marine and freshwater species.

The collection differs from Aotearoa's other significant national biological collections - think herbariums containing dried specimens of plants, for example - in that it is a living collection.

Curator Sarah Challenger has the job of keeping the collection alive and healthy. The microalgae require light of the right wavelengths, nutrients, and a suitable temperature to survive. Every three weeks Sarah carefully replaces the water and nutrients in the small plastic pottles in which the living samples are maintained.

Sarah says it is a much easier job to care for some of the freshwater microalgae, which can survive cryopreservation - or freezing - to very low temperatures and be brought back to life later as needed.

The Cawthron Institute's Chief Science Officer, Dr Cath McLeod, says the collection began with a monitoring programme for toxic phytoplankton blooms in the Marlborough Sounds that were having an impact on shellfish farms. The collection grew as the researchers realised that phytoplankton was a vast untapped resource which could potentially provide ingredients for food and pharmaceutical products.

Developing new food and drugs

Andy Selwood and Dr Matt Miller are currently screening about a hundred of the different strains to identify which ones might produce useful bioactive compounds. They grow each strain in a series of one-litre bioreactors, exposed to slightly different combinations of light and nutrients. This allows the researchers to identify optimum growth conditions and work out which strains are producing what kinds of bioactives and in what quantities. …

Go to this episode on rnz.co.nz for more details