BHAs

BHAs, or Bacterial Hydrogenases, are enzymes that catalyze the reversible oxidation of hydrogen gas (H2) to protons (H+) and electrons (e-) or the reduction of protons to hydrogen gas. They are found in various microorganisms, including bacteria, archaea, and some eukaryotes. BHAs play a crucial role in the metabolism of these organisms, particularly in hydrogen production and consumption, and are involved in the hydrogen cycle, a key process in the global carbon cycle.

BHAs are classified into three main types based on their structure and mechanism: [NiFe] hydrogenases, [FeFe] hydrogenases, and [Fe] hydrogenases. [NiFe] hydrogenases are the most abundant and versatile, containing a nickel-iron active site. [FeFe] hydrogenases have a more complex iron-only active site and are often found in anaerobic organisms. [Fe] hydrogenases, also known as hydrogenase-3, have a single iron atom as the active site and are typically found in aerobic organisms.

BHAs are of significant interest in biotechnology and energy research due to their potential applications in hydrogen production, fuel cells, and biohydrogenases. They are also used in the study of hydrogen metabolism and the hydrogen cycle. However, BHAs are sensitive to oxygen and can be inhibited by it, which limits their practical applications. Research is ongoing to develop BHAs that are more robust and efficient, particularly for use in industrial and energy applications.