Algal Carbon Dioxide Concentrating Mechanisms

摘要: Photosynthetic microorganisms like cyanobacteria and many eukaryotic algae acclimate to a limited availability of carbon dioxide (CO2) in their environment by inducing process called the concentrating mechanism. This uses an active inorganic (Ci; CO2 and/or HCO3−) uptake system that leads internal accumulation Ci levels significantly higher than extracellular levels. Carbonic anhydrase activity converts much accumulated hydrogen carbonate CO2, this substrate around Rubisco thereby optimising photosynthetic efficiency even under low conditions. The is further improved sequestration into specialised structures cyanobacterial carboxysome or pyrenoid algae. mechanism enhances fixation growth With increasing demands for sustainable energy sources, with efficient mechanisms are attractive models biotechnological transgenic applications biofuel biomass production. Key Concepts: The helps optimise photosynthesis limiting conditions. Rubisco both oxygen as substrates. Rubisco localised green alga, Chlamydomonas reinhardtii. The charged needs transporters enter cell cross organellar membranes. Carbonic enzyme carries out reversible interconversion reaction proceeds at faster rate uncatalysed reaction. At pH most form carbonate. Most can take up carbonate. Carbon diffuse so trap anion. Algae used large-scale production currently being explored sources bio-fuel. Keywords: algae; carbon mechanism; cyanobacteria; Chlamydomonas; photosynthesis; rubisco; pyrenoid; carboxysome; carbonic anhydrase; hydrogen transporter