Washington, August 26 : Scientists have determined that by tweaking the photosynthetic reactions of cyanobacteria, which is one of the most ancient groups of microorganisms in the world, they might be able to develop "carbon-neutral" clean energy.
Dramatic progress has been made over the last decade understanding the fundamental reaction of photosynthesis that evolved in cyanobacteria 3.7 billion years ago, which for the first time used water molecules as a source of electrons to transport energy derived from sunlight, while converting carbon dioxide into oxygen.
The light harvesting systems gave the bacteria their blue ("cyano") colour, and paved the way for plants to evolve by "kidnapping" bacteria to provide their photosynthetic engines, and for animals by liberating oxygen for them to breathe, by splitting water molecules.
For humans, now there is the tantalizing possibility of tweaking the photosynthetic reactions of cyanobacteria to produce fuels they want such as hydrogen, alcohols or even hydrocarbons, rather than carbohydrates.
Progress at the research level has been rapid, boosting prospects of harnessing photosynthesis not just for energy but also for manufacturing valuable compounds for the chemical and biotechnology industries.
Such research is running on two tracks, one aimed at genetically engineering real plants and cyanobacteria to yield the products humans want, and the other to mimic their processes in artificial photosynthetic systems built with human-made components.
Both approaches hold great promise and will be pursued in parallel, as was discussed at a recent workshop organised by the European Science Foundation (ESF).
According to Eva Mari Aro, the vice-chair of the ESF conference, there is now universal agreement over the ability of photosynthesis to provide large amounts of clean energy in future.
The current generation of biofuel producing crops generally convert less than 1 per cent of the solar energy they receive to biomass, which means they would displace too much agricultural land used for food production to be viable on a large scale.
There is the potential to develop dedicated systems, whether based on cyanobacteria, plants, or artificial components, capable of much higher efficiencies, reaching 10 per cent efficiency of solar energy conversion.
This would enable enough energy and fuel to be produced for a large part of the planet's needs without causing significant loss of space for food production.
A future aim is to build an artificial leaf-like system comprised of self-assembling nanodevices that are capable of regenerating themselves - just as in real plants or cyanobacteria.
According to Aro, "Fundamental breakthroughs in these directions are expected on a time scale of 10 to 20 years and are recognized by the international science community as major milestones on the road to a renewable fuel."