How can Chlamy, a type of microscopic algae, manage to produce hydrogen? Researchers from the University of Liège have just uncovered one of the mechanisms at the origin of this production. Could this process be amplified so that one day, Chlamy could be transformed into a producer of green energy we might use? It won’t happen tomorrow.

“Chlamy” is a small unicellular algae one-hundredth of a millimeter long, but it is generating a lot of commentary. For fifty years botanists have been using this green microalgae, full name, Chlamydomonas reinhardtii, as a model in the study of genes and molecular mechanisms involved in processes such as photosynthesis or nutrition, and have studied the motility of the organism’s flagellae. It has an atypical genome that combines characteristics of the plant world with others that are associated with microscopic animals. Chlamy has been stimulating the curiosity of scientists for a long time, and even now can still surprise them. Its genome was completely sequenced in 2003-2004, and since then the objective of research has been to identify the genes that it contains and their functions. Not long ago an international team of researchers, including two scientists from ULg (see the article, Genetic gold mine), published in Science the first results of their effort toward deciphering Chlamy’s genes.

Today, researchers from the laboratory of Photobiology and Plant Biochemistry (Dr. F. Franck) and the laboratory of Microorganism genetics (Prof. Cl. Remacle) have solved a long-standing mystery concerning photosynthesis by microalgae. The results of their research have been published in the prestigious scientific journal, the Proceedings of the National Academy of Sciences of the USA(1).

A chain of energy production

The main source of carbon in the biosphere is carbon dioxide. In order to be chemically joined with carbon-bearing molecules, carbon dioxide has to undergo a reduction that consists in it gaining protons and electrons. This reduction takes place during photosynthesis, a bioenergetic process through which plants, algae, certain bacteria and certain protists produce organic matter thanks to the energy provided by light. The series of phases of photosynthesis takes place in a specific entity, the chloroplast. This is located within the cytoplasm of plant cells and contains a membrane-like network made up of flattened-out vesicles known as thylakoids. In the thylakoid membranes, photosynthetic pigments are located, of which the best known are the chlorophylls.

(1) Jans F, Mignolet E, Houyoux PA, Cardol P, Ghysels B, Cuiné S, Cournac L, Peltier G, *Remacle C, *Franck F (2008) A type II NAD(P)H dehydrogenase mediates light-independent plastoquinone reduction in the chloroplast of Chlamydomonas. Proc Natl Acad Sci U S A. 105:20546-51 (* corresponding authors)