Outdoor cultivation of Chlamydomonas reinhardtii and its influence on hydrogen production

Stephanie Geier, Sabine Huyer, Konstantin Präbst, Moritz Husmann, Rainer Buchholz

Institute of Bioprocess Engineering, University Erlangen-Nuremberg, Paul-Gordan-Str 3, 91052 Erlangen, Germany

Hydrogen production by Chlamydomonas reinhardtii has been studied in the laboratory environment in detail but hardly under outdoor conditions. A biotechnical approach for photobiological H2 production comprises a process of at least two steps: one step to build up the necessary biomass and the subsequent second step of the actual H2 production under sulfate deprivation. In order to produce H2 under economic aspects, sunlight must be used. Within this project photoautotrophic and mixotrophic cultivation of Chlamydomonas reinhardtii could be demonstrated in outdoor experiments (in closed photo-bioreactors and in open ponds) as well as in laboratory experiments under simulated light profiles according to light quantities in central Europe (up to 2000 µmol m-2 s-1). Preliminary results even suggest that cultivation through the year is possible using waste heat. Bubbling with 10 % CO2 according to the CO2 content in flue gas was applied in order to increase cell numbers with no extra costs. The additional supply of CO2 led to a doubling of cell numbers under continuous illumination but not to a significant increase under the light profiles of an idealized summer day. However, the use of algae cells grown under high light profiles resulted in significant lower H2-yields (under laboratory conditions with continuous light) compared to the use of cells cultivated under continuous illumination and lower irradiance. Further efforts are required to firstly clarify H2 production under outdoor condition and secondly to optimize H2-yields.

e-mail address of presenting author: stephanie.geier@bvt.cbi.uni-erlangen.de

web site: http://www.bvt.cbi.uni-erlangen.de/