The Power of Microalgae – A Trip to a Biobased Micro-World

Tremendous Playing Field for Genetic Engineers

The diversity of microalgae offers a tremendous playing field for genetic engineers; but is has also been observed that the different strains react very differently to modifications, meaning that methods have to be developed individually and customized to the respective organism.

But genetic modification does not stop at productivity: Process relevant properties such as “flocculation on demand” can also be introduced, avoiding biofouling during the growth phase. Sapphire Energy has recently filed a patent for the genetic modification of photosynthetic organisms. In these, production of a flocculating moiety can be triggered by different promoters via light, temperature or other regulatory parameters.

Will the Car of the Future Run on Algae?

Major progress has already been made in the field of biofuel production with algae — be it bioethanol, biolipids, bio­diesel, hydrogen production or a combination of these. But the quest for more sustainable, biobased raw materials has led algae experts to look beyond ethanol or biodiesel.

According to a report in “Scientific American”, researchers at the Department of Energy’s National Renewable Energy Laboratory have “tweaked” cyanobacteria to produce ethylene. And one day cars powered by algae-biodiesel might even run on roads paved with algae based “bio-bitumen”: French AlgoSource Technologies is developing together with a couple of universities and research institutes a hydrothermal conversion process to produce viscous phases with bitumen-like properties.

Cultivation Principles of Microalgae

Two fundamental principles have been established for the cultivation of microalgae: Open ponds are the standard for the commercial production of a number of algal species. They require relatively little technology and allow for the production of algae biomass at moderate costs. The downsides are low biomass concentrations and productivities. So-called raceway ponds are available of the shelf in all sizes from lab equipment to large-scale production plants and account for almost 95 % of global microalgae production. The performance of raceway ponds depends strongly on location, but also on the efficiency of vertical mixing.

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