Microalgae – a sustainable protein alternative?

The potential of microalgae is enormous, which is why Agroscope is researching the options for using these microorganisms as feed ingredients for livestock.

As part of a long-term project called “Algafeed”, Agroscope researchers are aiming to produce a new source of protein for livestock on the basis of microalgae. To do this, they plan to set up microalgae production systems or “photobioreactors” (PBRs) directly on the farm. The objective is to develop a decentralised production system for protein-rich microalgae in order to supply locally made feed, thus reducing imports of soybean oilcake meal.

What are the advantages of microalgae?

Microalgae are an attractive alternative to soy thanks to their balanced biochemical composition, with essential amino acids, polysaccharides, polyunsaturated fatty acids, minerals, pigments and fibre. Their functional nutritional properties are comparable to those of soy.

Less water and arable land

Microalgae production requires no arable land: PBR systems are either installed on uncultivated land (e.g. along the walls or on the roofs of farm buildings), integrated with plants such as soil-less crops, or suspended above plantings that require partial shade. This means that microalgae production does not compete with the production of arable crops such as fodder and vegetables. The water used can be recirculated and no excess fertilisers are released into the environment, making the environmental impact lower than that of soy.

More protein

The crude protein content of microalgae can reach 60 percent by mass, compared with 36 percent for soy. Per hectare and per year, it is possible to produce around 30 times more microalgal protein than soy protein.

Sustainable and self-sufficient

The new protein source would provide a sustainable, self-sufficient supply of protein that is also “Swiss-made”. The protein would be produced directly where the livestock are reared, giving the producer complete control over the feed production chain. As an added benefit, microalgae could be cultured using nutrients from waste generated by the Swiss food industry.

Lower greenhouse gas emissions

Microalgae can convert CO2 into biomass, leading to an overall reduction in greenhouse gas emissions. Some strains even have the potential to reduce methane production by ruminants. And because protein is produced directly on the farm, all emissions associated with the transporting of livestock feed (soybean oilcake imports) are eliminated.

Virtually independent of climate

The production of plant protein is strongly influenced by climate change, but this is not the case for protein obtained from microalgae, which are cultured under protected conditions in PBRs.

Project stages

Algafeed is a multi-stage project. The current stage (technical and economic feasibility) is looking at the following topics:

Selection of microalgae species: microalgae are selected on the basis of protein content and biochemical composition (nutritional value and high value-added nutrients such as trace elements, vitamins, fatty acids, recognised pre- and probiotics, etc.). The ability of microalgae to withstand extreme culturing conditions is another key criterion, given that the aim is to produce protein without the high energy consumption associated with temperature control.
Development of culturing systems: to increase the productivity of a microalgae culture, culturing systems are being improved (notably by optimising the light source and improving gas exchange).
Optimising the specific culturing method to ensure that the processes involved are suitable for future on-farm application and the nutritional values of the resulting microalgae are ideal for use in animal feed. Downstream processes are also being optimised to ensure good feed digestibility, ease of administration and keeping nutritional qualities.
The digestibility of the end product will be tested in in vitro studies using the INFOGEST system and palatability tests in livestock are planned.
In-depth assessment of environmental impact combined with techno-economic viability.

First steps

Native microalgae from a wide variety of ecological niches are being collected and incorporated into a strain collection called AlgoScope. The aim is to identify the microalgae best suited to Swiss weather conditions. The composition of the collected microalgae will be analysed to determine which strains produce viable amounts of protein.
The A’propos project, which aims to implement microalgal protein production using nutrient-rich secondary flows from the agri-food sector, is set to begin in 2023. Flows normally regarded as waste, such as whey or potato blanching water, will be converted into microalgal biomass, which in turn will be used to feed livestock. The project is supported by the FOEN and is being conducted in partnership with industry and the semi-public sector (Frigemo-Fenaco, “Cotting et Fils SA” and Ava Altenrhein) and the ZHAW University of Applied Sciences.
Microalgae culturing methods are being developed, ranging from laboratory scale to pilot scale (around 200 litres).

Next steps

Collection of microalgae strains will continue and resilient cultures will be developed for year-round use.
A mobile microalgae production facility will be made available for field trials and demonstrations.
Methods of conditioning microalgal biomass will be developed to make microalgae a highly digestible feed that is readily accepted by livestock.
Palatability tests will be carried out in pigs and ruminants.