Biological hydrogen production (Algae)

A hydrogen bioreactor is a bioreactor in which takes place the biological production of hydrogen gas. The production of hydrogen gas may be effected in various ways. Thus, algae can produce hydrogen under certain conditions. In the late 1990s it was discovered these behavioral changes in the algae of sulfur deficiency. The algae can set the generation of oxygen and produce hydrogen gas. Another possibility is the construction of a hydrogen bioreactor, form the base of bacteria. In this case, it is possible to establish a two-stage system in which thermophilic bacteria, and cyanobacteria are used.

A technology of this type is interesting insofar as that of the so- produced bio-hydrogen can be used as a climate- neutral energy source. So could produce in the size of Texas enough hydrogen to meet the global energy demand algae farm. The hydrogen production from a breed of 25,000 square kilometers could replace the entire fuel consumption of the United States. This is less than one-tenth of the area of ​​soybean production in the USA ( 2006).

History

In 1939, the German -born biochemist Hans Gaffron discovered in green algae the ability to temporarily produce hydrogen. Until then, it was assumed that only prokaryotic organisms have this ability. The background of this process he could not clarify, however.

Around 1990 Anastasios Melis observed, a researcher at the University of California at Berkeley that sulfur deficiency in the alga Chlamydomonas reinhardtii, a change in the photosynthesis process causes, which in turn is hydrogen production described by Gaffron basis.

To be used in power generation, however, it is necessary to make the hydrogen production more efficient (or economic ). Thus it succeeded in 2006 Researching the Universities of Bielefeld and Queensland to change the alga Chlamydomonas reinhardtii genetically to the effect that they can produce up to a factor of five to hydrogen compared to the wild type.

Problems in the planning of a bioreactor

• Obstruction of photosynthetic hydrogen production by the emergence of an electrochemical potential
• By competitive inhibition of the production of hydrogen is hindered by carbon dioxide.
• For efficient photosynthesis a bicarbonate compound is needed.
• Elimination of electrons
• The efficiency is very small. The normal efficiency (conversion of sunlight into hydrogen) must at least 7 to 10 percent so as to be economical. In their natural form but the algae reach only 0.1%.

You try to solve these problems with the help of biotechnology.

Investigation

2006 - At the University of Karlsruhe, a prototype of a bioreactor is constructed that holds 500-1000 liters of algae substrate.