The world of microalgae and cyanobacteria represents a formidable reservoir of biodiversity that has barely been explored (30,000 species described, 1 million estimated). There is considerable, and virtually untapped, potential for the production of bioenergy through the action of photosynthetic micro-organisms. Some microalgae have developed original metabolic capacities, such as the ability to produce hydrogen or accumulate lipid reserves (up to 60% of cell content) using water,CO2 and solar energy as their main resources, making it possible to develop clean, sustainable biofuel production processes through large-scale cultivation.
However, applications in this field face biological and technological hurdles. In the field of bio-hydrogen, a major biological limitation is the sensitivity of hydrogen-producing enzymes (hydrogenases) to molecular oxygen. We will show how research strategies combining the exploration of biodiversity and genetic engineering can overcome this type of obstacle. In the field of lipid production (which is a source of biodiesel), a major limitation is that the accumulation of high-energy compounds (reserve compounds such as starch or lipids) occurs in response to unfavorable growing conditions (e.g. nutrient deficiency), severely penalizing the system's productivity. We will discuss how our understanding of biological mechanisms and their regulation, combined with recent advances in genomics and systems biology, now provide us with the tools and concepts needed to domesticate photosynthetic micro-organisms for energy production.
