Algae-rithms: a volcanic solution?

As reported 6 April 2023, Wageningen University scientists in the Netherlands have developed a method to produce a protein-rich microalgae species that grows in volcanic hot springs. The research is part of a four-year European-funded Horizon 2020 research project, ProFuture, which aims to scale up microalgae production and prepare the market uptake of microalgae proteins as ingredients for food and feed products. The story on our LinkedIn page received enormous interest, generating to date +1,000 reactions.

Galdieria sulphuraria is a resilient and adaptable extremophile species that can survive in extreme environments otherwise not conducive to life, but hitherto had not been assessed as a potential food source that could be produced at scale.

Its biomass was found to have protein content in the range of 62-65%, which is relatively high compared with other algal and fungal microorganisms with protein contents.

Microalgae are a natural source of essential fatty acids. Notably, the proteins contain high levels of cystine and methionine, two amino acids not generally found at such levels in non-animal-based proteins.

Galdieria sulphuraria is also a stable source of a natural antioxidant blue pigment often used as a colorant in cosmetics and food.

Protein Production Technology International asked Pedro Moñino Fernández, Ph.D student and lead researcher on the project, to fill in some blanks:

Please could you describe your research and method to produce a microalga species from volcanic hot springs?

“At WUR we are working on scaling and optimizing the technology to grow Galdieria in our pilot facilities as there are currently no protocols to produce Galdieria at industrial scale. We are currently focusing of the development of a mixotrophic process (cells growing on sunlight+CO2 and organic sugars simultaneously), as this cultivation type allows to reduce the energy input required while increasing productivity and using the substrate very efficiently.”

How relevant is temperature?

“This microalga is adapted to warm temperatures (up to 56 degree Celsius), which makes it a suitable species for hot weather and/or warm locations; most microalgae cannot handle such high temperatures. On the contrary, it grows poorly at low temperatures.”

Please describe Galdieria sulphuraria and how it was discovered and tested?

“Galdieria sulphuraria is an extremophilic microalga that thrives at low pH (<2) and high temperature (up to 56 °C). It was isolated from green [microbial] mats found in acidic hot springs from volcanic areas, the environment that they usually colonize.”

Please describe its nutritional profile and how it was assessed?

“Galdieria has a high content of proteins (>60%) and is rich in essential amino acids, especially methionine and cysteine. In addition, it contains the blue pigment phycocyanin that has antioxidant properties. This has been assessed by measuring the quantity and proportion of amino acids in the biomass.”

How does it compare with other food protein sources?

“Galdieria contains a larger relative fraction of essential amino acids than most plant and algal food sources, including soybean and other microalgae as Chlorella or Spirulina. Moreover, its total protein content (>60%) is also on the high side of the currently used/described sources of single cell protein.”

How is it being used as a protein source and will it be applied commercially?

“Currently Galdieria is still in the research phase. While there are some companies developing processes for the production of phycocyanin, the species has not been approved as a novel food yet.”

How is the research developing and where is it going?

“At the moment most of commercial research focuses on the production of phycocyanin with Galdieria via heterotrophic processes (where cells grow only based on organic sugars, for example glucose). There is a growing interest in producing Galdieria as single cell protein and as a source of other compounds mainly via heterotrophic or mixotrophic processes.”