Huge breeding potential in microalgae

In order to grow, algae require light, temperature, and nutrients. However, growth is also affected by algae genes. Therefore, scientists tested whether it is possible to selectively breed microalgae so that the next generation produces higher yields, the generation after that produces higher yields than the previous one, and so on.

“We wanted to know whether breeding can contribute to faster growth and increased omega-3 content. The initial trials we carried out yielded very promising results,” said Marie Lillehammer, a senior scientist at Norwegian research institute Nofima.

The researchers are probably the first to calculate genetic variation in microalgae.

Many microalgae reproduce vegetatively. Therefore, the scientists chose the species Seminavis robusta – a well-studied alga that has sexual reproduction. Eight lines of the species were crossed with each other in one generation and tested in the breeding trial.

25% growth increase

Although the species is not very relevant as a feed resource, the trial showed that 18% of omega-3 production in the algae is determined by the genes (heritability). Selective breeding gave an 8.8% increase of omega-3 in one generation.

Growth percentages were even higher. With a 50% heritability, the microalgae grows 25% faster per generation; in theory, a ninefold increase per year, given 10 generations in one year.

“It may be that inbreeding and physiological limitations would halt growth over generations, or growth would have side effects. However, the trial shows that breeding should be explored further if microalgae is to become an important feed ingredient for European aquaculture,” said Lillehammer.

The research is part of the NewTechAqua project, which is financed by the EU through Horizon 2020, and runs in collaboration with Universidad de Las Palmas and Ghent University.