Microalgae strain from volcanic hot springs has ‘protein-rich food’ potential

The development comes in the fourth year of European-funded Horizon 2020 research project ProFuture.

Instigated in 2019 and running for a period of four years, the project aims to scale up microalgae production and prepare the market for uptake of microalgae proteins for both food and feed.

Microalgae is thought to be amongst the most promising candidates to help provide sustainable, nutritious protein to growing populations, explained the ProFuture group coordinated by the Institute of Agrifood Research and Technology (IRTA) in Spain.

Group participants include representatives from Wageningen University & Research, Ghent University, Coop Group, AlgoSource, and EUFIC.

“However, for the microalgae value chain to become more sustainable and competitive, innovative technology and cost-effective production processes must be put in place. That is the core mission of the ProFuture project.”​

Elevated protein content​

In working to achieve this mission, researchers at Wageningen University in the Netherlands have developed a way of producing a microalga species with ‘great potential’ as an alternative protein source.

The researchers found the Galdieria sulphuraria strain growing in hot springs near Naples, Italy. The extremophile microalga has a blue pigment, and since it is capable of living in extreme conditions, is thought to prove a resilient source of protein for the future.

The ProFuture researchers claim this is the first time the strain is being examined as a possible food source. The project also marks the first time G. sulphuraria has been produced at scale.

So what are its potential nutrition benefits? The strain was found to have a protein content in the range of 62-65%, which is relatively high compared to other algal and fungal microorganisms with protein contents ranging from 30-70%.

In addition, G. sulphuraria proteins have a good amino acid profile, including all essential amino acids. The proteins are especially rich in two amino acids rarely found in such high levels in non-animal-based proteins: cystine and methionine.

A source of blue pigment?​

Nutrition aside, the researchers also see potential in the microalga strain’s pigment. G. sulphuraria is amongst the few natural sources of blue pigments, explained Iago Dominguez Teles, the project manager at Wageningen University.

Indeed, the strain contains a high concentration of a natural blue pigments commonly used by the food industry, as well as in cosmetics. Compared to extracts of the already commercially produced microalgae strain Spirulina, the blue pigments extracted from G. sulphuraria look to outperform in terms of stability. This, the researchers suggest, could increase its potential in industrial applications. The pigment has also been found to contain antioxidant properties.

Scaling Galdieria sulphuraria​

The scale production of the microalga strain, the researchers developed a process using mixotrophy. The technique combines both photosynthesis and sugar-based feedstock to stimulate the growth of microalgae.

The researchers demonstrated pilot production in a 13,000L (1.5 cubic metre) bioreactor Wageningen University.

As to next steps, in order to effectively exploit the ‘promising’ results of G. sulphuraria, researchers will need to assess its digestibility and identify any additional processing methods that may be required for commercial applications.

“The European Food Safety Authority (EFSA) is currently assessing the safety of Galdieria sulphuraria as a novel food for the general population and as a food supplement for adults. In addition, Blue Galdieria extract is [being] assessed as a food additive,” ​noted the research team.