Algae Biofuels and the Prisoner's Dilemma - 2013 News Article and Publication
Could new advances based around the old Prisoner's Dilemma make algae biofuels cost-competitive, sooner? New research suggests that it appears so.
The Prisoner's Dilemma can be summed up as even though the prisoners mutually benefit from silence, prisoner A reasons that, no matter what the prisoner B does, he himself does better by betrayal. And vice versa.
Microalgae have large rates of biomass accumulation due to their high photosynthetic efficiencies. This makes them great candidates for producing green chemical feedstocks and biofuels, particularly oil-based aviation fuels. However, more productive strains of algae must be identified that out perform current strains in harvesting light energy for biomass production.
In the world of algae biofuels researchers puzzle over the problem of light harvesting and light processing. Algae are able to capture almost 100% of light reaching them, but they don't have the ability to process all that light into energy, and most of it is dissipated as heat or florescence. In relating algae to the Prisoner's Dilemma, Alga A and Alga B would both benefit by cooperating to harvest less light and process it more efficiently. But instead the algae choose betrayal and harvest more light at the expense of the other.
Although microalgae have light-capturing antennae that are efficient at capturing photons, they are not as productive in a dense population. The algae at the surface capture more light than they can use and they shade the algae below the surface. In the wild this gives them a competitive advantage.
Optimizing the size of the light harvesting antennae reduces light energy waste and allows photons to reach the algae below the surface. Photosynthesis can occur more uniformly throughout a culture.
New Mexico Consortium's latest biofuels research found the optimum antennae size for maximizing biomass production, as well as the gene to manipulate to produce this antennae size. The latest publication in Algal Research, “Optimization of photosynthetic light energy utilization by microalgae,” by Zoee Perrine, Sangeeta Negi and Dick Sayre, found that by reducing light harvesting capabilities they found a two fold increase in photosynthetic rate at high light intensities and a 30% increase in growth rate at saturating light intensities.
This research shows that a more optimal light distribution strategy is available to algae but they don’t take it, because they find themselves in the Prisoner’s Dilemma, unable to communicate with each other and cooperate for maximum mutual benefit. Consequently, when growing algae for biofuels, researchers can assist the algae communities to grow faster, with improved photosynthetic efficiency and productivity. This means more algae, more productivity, and more biomass for harvest.