You are here

Research funded by EERE’s Fuel Cell Technologies Office has dramatically increased the efficiency of biofuel production by changing certain genes in algae to make them pale green. Dr. Tasios Melis of the University of California, Berkeley is making stable changes to the algae’s genes to reduce the size of the chlorophyll antenna (a structure that collects light for photosynthesis). Dark green cells, which have larger antennae, collect more light than the cells can use. The excess light energy is lost as heat. Paler green cells with shorter antennae use sunlight more efficiently, with each individual cell collecting just enough light to power itself. This allows the excess light, which would have been wasted by darker green algae, to reach, and be productively used by, other algae lower down in the pond. This increased efficiency results in increased chemical energy production per acre of algae. Producing this chemical energy is the first step in producing photosynthetic fuels (like hydrogen).

Dr. Melis and his team searched through thousands of mutant algae strains for those that had a lighter color relative to their “normal” parent strain and were more efficient at converting light into chemical energy. His lab focused on three such strains—which they called truncated light-harvesting antenna (tla) mutants—to find out which genes were responsible for the size reduction in antennae so that the discovery could be applied to other strains of algae.

Dr. Melis’ lab showed that two of these strains—tla2 and tla3—are each missing a different gene that is involved in assembling the antennae. The light utilization efficiency of normal, dark green cells is only 3%, but the tla2 and tla3 strains have efficiencies of 15% and 25%, respectively—500% and 800% more efficient than the original strain. Dr. Melis’ model shows that, under real world conditions, these efficiency improvements could result in a 300% improvement in fuel production (since the improved efficiencies only have their full effect during the middle of the day, at higher levels of light). Dr. Melis also recently published a review that discusses the potential use of these strains as a tool to maximize photosynthetic productivity. Now that the genes have been identified, biofuel researchers in industry and academia can use these findings to improve other strains of algae.

The Fuel Cell Technologies Office (FCTO) conducts comprehensive efforts to overcome the technological, economic, and institutional barriers to the widespread commercialization of hydrogen and fuel cells.

The Office of Energy Efficiency and Renewable Energy (EERE) success stories highlight the positive impact of its work with businesses, industry partners, universities, research labs, and other entities.

Project Overview

Positive Impact

Research funded by EERE’s Fuel Cell Technologies Office has dramatically increased the efficiency of biofuel production by changing certain genes in algae to make them pale green.

Locations

University of California, Berkeley

EERE Investment

$1.74 million

Clean Energy Sector

Sustainable transportation