Bio-energy may contribute considerably to the world’s future
energy supply, but its production requires land and water to do so
[1]. Micro-algae have been seen as promising pathway to produce
bio-energy with limited (agricultural) land and water resources.
High oil content, and a high photosynthetic conversion efficiency
are other arguments in favour of micro-algae [2–5]. The
maximum theoretical conversion efficiency of solar energy to
micro-algae biomass is 9% [6], compared to a conversion efficiency
of 2–3% of C4 plants. Micro-algae are unicellular organisms, consisting
mainly of carbon, hydrogen, oxygen and nitrogen and are
categorised as aquatic biomass. Sunlight availability is the most
important factor determining micro-algae growth, followed by carbon
and nutrients. Apart from bio-energy, micro-algae can also be
used for food, feed and chemical products [6–9].