Macro algae – the blue biomass of the future

If we, in the future, change our attitudes towards areas of cultivations and dare to think differently by e.g. including the ocean as an area of cultivation, there are great possibilities for the cultivation of macro algae (seaweed) in Denmark. And like feed wheat, macro algae are very suitable for biorefining.

Advantages

There are many advantages to the exploitation of macro algae:

• The biomass return from macro algae per hectare is larger than the return from traditional energy crops.

• So far tests show that macro algae are suitable for feed mixtures in the animal husbandry. This means that the remaining mass from the energy production can be used as a high-value protein to be mixed with animal feed, just like winter wheat. 

• Several brown algae species are particularly suitable because of their high amount of carbohydrates, which makes it suitable for the production of bioethanol or biogas. 

• Preliminary tests show that the content of amino acid and omega3 found in brown algae makes it suitable for feed and especially the rising fish production, whereas today, minnows are used in feed mixtures to feed large fish. This is in no way a sustainable solution, why the use of brown algae carries an enormous potential to replace minnows in fish feed. 

• Macro algae can be cultivated in both salt water and brackish water, why no fresh water is needed in the production.

Challenges

The potential is huge, but there are still challenges connected to the use of macro algae.

These challenges include:

• The need for further development within the production of macro algae, along with how these are harvested in a large scale. There is a need to find a method for a structured way to plant and harvest the algae, so that the amount can be controlled and managed according to need.

• An enzyme needs to be developed in order to make possible the fermentation of macro algae’s structural carbohydrates, which are very persistent.