photobioreactor system for computer controlled cultivation of microalgae

• Published in: Journal of applied phycology Vol. 17; no. 6; pp. 535 - 549
• Main Authors: Marxen, Kai, Vanselow, Klaus Heinrich, Lippemeier, Sebastian, Hintze, Ralf, Ruser, Andreas, Hansen, Ulf-Peter
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01-12-2005; Springer
• Subjects: Algal culture (microalgae); Biological and medical sciences; Biotechnology; chlorophyll fluorescence; control loop; frequency analysis; Fundamental and applied biological sciences. Psychology; Marine; Methods. Procedures. Technologies; optical sensors; physiostat; Synechocystis; UVB-radiation; Physiological condition; Chlorophyll; physiostat; UVB radiation; Algae; chlorophyll fluorescence; Fluorescence; optical sensors; control loop; frequency analysis; Photobioreactor; UVB-radiation; Microorganism culture; Development; Kinetics; Thallophyta
• ISSN: 0921-8971; 1573-5176
• DOI: 10.1007/s10811-005-9004-8

A bioreactor system was developed for the cultivation of the microalgae Synechocystis sp. PCC6803 under controlled physiological conditions. The determination of the actual physiological state of the microalgae was provided by inline recording of chlorophyll fluorescence parameters. A feed-back loop was employed to keep the microalgae in a defined physiological state. For the construction of this feed-back loop, the temporal behaviour of the system was investigated using changes in light conditions (as caused by modulated UVB radiation) as input signal and chlorophyll fluorescence as output signal. The reproducibility of the responses was high. Kinetic analysis based on curve fitting revealed two time constants in the UVB-induced responses. The knowledge of these time constants was utilised for the development of an efficient feed-back loop which allows the cultivation of the microalgae in a defined physiological state. This new process strategy (called physiostat) was successfully tested. The performance in a culture of growing microalgae is shown.