Solar energy conversion by green microalgae: A photosystem for hydrogen peroxide production

• Published in: Biotechnology and bioengineering 2001-09, Vol.74 (6), p.539-543
• Main Authors: de la Rosa, F. F., Montes, O., Galván, F.
• Format: Article
• Language: English
• Subjects: Animals; bioconversion; Biofuel production; Biological and medical sciences; Biotechnology; Chlamydomonas reinhardtii; Chlamydomonas reinhardtii - metabolism; Chlorella - metabolism; Chlorella fusca; Chlorophyta; Chlorophyta - metabolism; Energy; Freshwater; Fundamental and applied biological sciences. Psychology; green microalgae; hydrogen peroxide; Hydrogen Peroxide - metabolism; Hydrogen-Ion Concentration; Industrial applications and implications. Economical aspects; Methods. Procedures. Technologies; methyl viologen; Microbial engineering. Fermentation and microbial culture technology; Models, Chemical; Monoraphidium braunii; Oxygen - metabolism; Photosynthesis; photosystem; solar energy; Time Factors
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/bit.1146

A photosystem for solar energy conversion, comprised of a culture of green microalgae supplemented with methyl viologen, is proposed. The capture of solar energy is based on the Mehler reaction. The reduction of methyl viologen by the photosynthetic apparatus and its subsequent reoxidation by oxygen produces hydrogen peroxide. This is a rich‐energy compound that can be used as a nonpollutant and efficient fuel. Four different species of green microalgae, Chlamydomonas reinhardtii (21gr) C. reinhardtii (CW15), Chlorella fusca, and Monoraphidium braunii, were tested as a possible biocatalyst. Each species presented a different efficiency level in the transformation of energy. Azide was an efficient inhibitor of the hydrogen peroxide scavenging system while maintaining photosynthetic activity of the microalgae, and thus significantly increasing the production of the photosystem. The strain C. reinhardtii (21gr), among the species studied, was the most efficient with an initial production rate of 185 μmol H2O2/h · mg Chl and reaching a maximum of 42.5 μmol H2O2/mg Chl when assayed in the presence of azide inhibitor. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 74: 539–543, 2001.