Ensayos de producción de hidrogeno con proteobacterias

Abstract

One of the biggest challenges of the upcoming decades is to find renewable energy sources that can replace the extreme dependence on fossil fuels. So far, most energy sources are born of some kind of treatment or conversion of fossil fuels, which continues to contribute to environmental pollution. For this reason, in recent years has increased interest on hydrogen (H2) as power source. Hydrogen is the most abundant element of the universe, due to the 90% of the matter is constituted by it. Even though, hydrogen does not exist isolated in nature by itself and it has to be generated. These processes require a high energy investment, for this reason the industry has gradually started to bet on the bioproduction of hydrogen as energy source. There are different ways of producing hydrogen by using microorganisms, but the most effective one is photofermentation mediated by photosynthetic non-sulfur bacteria. These bacteria grow in anaerobic conditions and under exposure to light, and can use different substrates as a source of carbon and nitrogen. In addition, they present a flexible and varied metabolism, emphasizing the participation of the enzyme nitrogenase during the anaerobic production of hydrogen. In the present study hydrogen production mediated by three proteobacteria strains has been verified (Rhodobacter sp, Rhodopseudomonas sp. and Rhodopseudomonas pseudopalustris) using two different analytical methods, gas chromatography and monitoring the production with a hydrogen sensor. Using the first approx., the effects of nitrogen in the nitrogenase activity and hydrogen production has been studied. The obtained results demonstrated that under a nitrogen saturated atmosphere, direct hydrogen synthesis was inhibited. While, in absence of nitrogen hydrogen production is observed by these bacteria. On the other hand, with the use of hydrogen sensor, we demonstrated that nitrogen’s effect inhibits the nitrogenase activity and that these bacteria have the ability to produce hydrogen with light and without it. The different hydrogen concentrations achieved by each bacterium indicate that each strain needs specific production conditions to accomplish an efficient performance