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Microalgae - a definition |
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First published in Cleantech magazine, July 2008. Copyright Cleantech Investor 2008. This definition was published in conjunction with a feature entitled The Algal Biorefinery, by Simon Bennett Attention is focused on microalgae, extremely primitive marine plants lacking the physical structures that support land plants and macroalgae such as seaweed. Microalgae have very high photosynthetic rates which allow them to translate sunlight into high rates of biomass growth that are unavailable from crops, e.g. at least ten times the yield per hectare compared to palm oil. Apart from a small amount of nutrients, their only requirements are a water supply and a CO2 feed, both of which can be taken from waste sources such as power station chimneys.
There are many thousand species of algae, even in British waters, and all contain proteins, vitamins and oils that can be farmed and extracted. This offers a huge screening challenge, but a great chance of finding organisms with better attributes for industrial applications. These attributes include higher concentrations of natural oils, usually between 20% and 40% by weight, making algae particularly suitable for biodiesel production, which currently relies on other sources of vegetable oil such as rapeseed or palm.
This combination of extractable chemicals, high procreation rates and variety of breeds has led algae to be termed ‘factories’ for the materials of the future. Furthermore, as non-food resources which are supported off-shore or on infertile land, algae may be the only route to the sustainable displacement of high proportions of oil consumption. |
