Researchers probe microalgae as viable alternative to fish

Microalgae could provide an alternative source of healthy omega-3 fatty acids for humans while also being more environmentally friendly to produce than popular fish species, a new study by scientists from Martin Luther University Halle-Wittenberg (MLU) has suggested. 

Microalgae have been the focus of several decades of research – initially as a raw material for alternative fuels, but more recently as a source of nutrients in the human diet. They are mainly produced in open ponds in Asia; however, these ponds are said to be at risk of potential contamination.

Also, some species of algae are easier to cultivate in closed systems – so-called photobioreactors. “We wanted to figure out whether microalgae produced in photobioreactors in Germany could provide a more environmentally friendly source of essential nutrients than fish,” said Susann Schade from the Institute of Agricultural and Nutritional Sciences at MLU. Up to now, photobioreactors had usually only been compared to pond cultivation and they often scored worse due to their higher environmental impacts, the researchers explained. “However, little research has been done on the precise extent of the environmental impacts of algae produced for human consumption, especially under climatic conditions such as those found in Germany,” Schade added.

For their study, the researchers developed a model to determine location-specific environmental impacts. “One of the things we did was to compare the carbon footprint of nutrients from microalgae and fish. We also analysed how much both food sources increase the acidification and eutrophication in water bodies,” explained Dr Toni Meier, Head of the Innovation Office nutriCARD at MLU.

The researchers were able to show that microalgae farming has a similar impact on the environment as fish production. “However, if we compare the environmental effects in relation to the amount of omega-3 fatty acids produced, fish from aquaculture comes off far worse,” Schade said.

One advantage of algae cultivation is said to be its low land consumption; even infertile soils can be used. In contrast, both open ponds and the cultivation of feed for aquaculture require very large areas of land. In particular, fish species that are popular in Germany, such as salmon and pangasius, are primarily produced through aquaculture and therefore put the environment under a considerable amount of pressure, the researchers noted. However, even fishing wild Alaska pollack had poorer values than microalgae for all environmental indicators.

“Microalgae should not and cannot completely replace fish as a food source. But if microalgae could be established as a common food, it would be another excellent environmentally friendly source of long-chain omega-3 fatty acids,” Meier said.