Hydrogenase:For the Clean Energy Production

Introduction 
 Hydrogenase is a group of enzymes which has a able to produce and slid hydrogen. Such ability of the enzyme can be use to produce clean energy. An international team lead by researchers from UCL (UK) and CNRS (France), including an Ikerbasque Research Fellow from CIC nanoGUNE, have combined theory and experiment to characterize each chemical reaction step that results in the reduction of oxygen by the enzyme. These results have been published in the journal Nature Chemistry.

 History Of The Fossil Fuels.

Fossil fuels supply over 80% of the world's energy. Since the energy crises in 1970s and soon. Increased prices of fuel and low level of the fuel is a warning the world to wake and use the biotechnology and make efficient fuel. In the next step the scientist move to One possibility is using enzymes called hydrogenases that naturally occur in various microorganisms that live in anaerobic ecosystems, such as some bacteria living in soil and in the intestinal tract of animals, or unicellular algae.

 Mechanism

 Hydrogenases catalyze the conversion of protons in hydrogen molecules (H2), whose combustion releases energy that can be utilized for example in fuel cells and therefore be part of biotechnological devices. The active site that catalyzes this reaction contains metallic ions (Iron or both Iron and Nickel). The Iron-only variety of hydrogenases is the most active for the production of hydrogen molecules. Their remarkably complex active site -the so-called H-cluster- is buried within the core of a large protein. A fatal problem for being able to exploit hydrogenases in biotechnological applications is that when brought to the aerobic conditions of a bioreactor (under normal oxygen pressures), molecular oxygen degrades their active site. Understanding the mechanism of the degradation process of the H-cluster is therefore essential to design a hydrogen-based fuel cell, but studies so far had not been conclusive. To solve this conundrum, an international team of researchers has combined experiments, molecular simulations, and theoretical calculations. Using electrochemical methods, they have precisely measured the rates of the different reaction steps involved in the degradation of the enzyme by oxygen. They have studied the dependence of these rates on experimental parameters like the electrode potential, pH, H2O/D2O exchange, and mutation of specific amino acids in the protein. These results confirm predictions from theoretical calculations. The study published on August 22nd in Nature Chemistry has allowed to characterize unambiguously the complex reactions that occur in these large biological macromolecules using a highly innovative combination of computational and experimental approaches. "Although important challenges remain ahead for industrial applications, this study opens new avenues to efficiently exploit enzymes from living systems for clean energy production," says De Sancho.


 Source of the story: science daily