Reliable production of microalgae biomass using a novel microalgae platform

A microalgae platform, consisting of four photobioreactor units incorporating a novel biomimetic design, has been installed at the Biosolar Center in Koethen, Germany. The novel photobioreactor consists of a flexible, tubular double-wall hose system (silicone based) with integrated temperature control in a closed cycle. The modular-arranged platform system (total cultivation volume 1700 L) has been designed for stable long-term cultivation of microalgae biomass in outdoor use. Cultures with Scenedesmus and Chlorella species have been grown outdoors at their optimal growth temperature (avg. 26 A degrees C) for 145 days during spring and summer and were tested successfully for the stable production of microalgae (avg. biomass productivity 0.3 g L-1 day(-1) (max. 0.75 g L-1 day(-1))) with an overall photosynthetic conversion efficiency of 7.2 % based on photosynthetically active radiation. The average calorific value of the produced biomass is 23.25 MJ kg(-1) with defined product quality (content relating to biomass dry weight: proteins 0.40 g g(-1), lipophilic compounds 0.38 g g(-1) and total carotenoids 11 mg g(-1)). This outdoor concept is continuously adjustable to maintain an optimal environment for microalgae cultures (in particular light entry, temperature control and limiting of oxygen levels).