Algaculture

Algaculture is a form of aquaculture involving the farming of species of algae.

The majority of algae that are intentionally cultivated fall into the category of microalgae (also referred to as phytoplankton, microphytes, or planktonic algae). Macroalgae, commonly known as seaweed, also have many commercial and industrial uses, but due to their size and the specific requirements of the environment in which they need to grow, they do not lend themselves as readily to cultivation (this may change, however, with the advent of newer seaweed cultivators, which are basically algae scrubbers using upflowing air bubbles in small containers, known as tumble culture).

Commercial and industrial algae cultivation has numerous uses, including production of nutraceuticals such as omega-3 fatty acids (as algal oil) or natural food colorants and dyes, food, fertilizers, bioplastics, chemical feedstock (raw material), protein-rich animal/aquaculture feed, pharmaceuticals, and algal fuel, and can also be used as a means of pollution control and natural carbon sequestration.

Global production of farmed aquatic plants, overwhelmingly dominated by seaweeds, grew in output volume from 13.5 million tonnes in 1995, to just over 30 million tonnes in 2016 and 37.8 million tonnes in 2022. This increase was the result of production expansions led by China, followed by Malaysia, the Philippines, the United Republic of Tanzania, and the Russian Federation.

Cultured microalgae already contribute to a wide range of sectors in the emerging bioeconomy. Research suggests there are large potentials and benefits of algaculture for the development of a future healthy and sustainable food system.

Several species of algae are raised for food. While algae have qualities of a sustainable food source, "producing highly digestible proteins, lipids, and carbohydrates, and are rich in essential fatty acids, vitamins, and minerals" and e.g. having a high protein productivity per acre, there are several challenges "between current biomass production and large-scale economic algae production for the food market".

Australian scientists at Flinders University in Adelaide have been experimenting with using marine microalgae to produce proteins for human consumption, creating products like "caviar", vegan burgers, meat substitute, jams and other food spreads. By manipulating microalgae in a laboratory, the protein and other nutrient contents could be increased, and flavours changed to make them more palatable. These foods leave a much lighter carbon footprint than other forms of protein, as the microalgae absorb rather than produce carbon dioxide, which contributes to the greenhouse gases.

Both microalgae and macroalgae are used to make agar.