Microalgae at the Gaspump

Dr. Sara Calhoun

Alternative sources of energy are critical for the long-term survival of our planet. Last year, over 140 billion gallons of gasoline were consumed in the US and most of our gas comes from fossil fuels. But there is potential in a new alternative fuel source that comes from a group of microscopic organisms, which perform amazing chemistry. This group of organisms is the microalgae.

I'll share three reasons why I think microalgae are a great source for biofuels. First, they can perform photosynthesis. They take up carbon dioxide from the atmosphere and with water convert sunlight into chemical energy. This means they're self-sustaining and carbon neutral. Second, they naturally produce molecules that are precursors to fuel. They accumulate these oily droplets, which are made of a class of molecules we call lipids. These lipid molecules can be extracted and converted to biodiesel. Third, many species are aquatic. We can cultivate them in water, including salt water or wastewater, rather than on land, which we use for growing food.

This sounds great, but the problem is that the overall cost for making algae-based biofuels is too high to compete with conventional fuels. So, we're still looking for the right strain of algae that will give us the most bang for our buck - the fastest growing, most efficient strain.

Our collaborators across different national laboratories are screening for which strains of algae grow the best over a variety of conditions. Oftentimes, the most promising candidates are new to us, so we know very little about their biology. The goal of my research is to characterize these new strains of algae.

At the Joint Genome Institute, where I work, we sequence the genomes of these candidate biofuel strains. The genome acts as a blueprint for those who perform the genetic engineering. We also evaluate how the algae respond when we alter its growing environment. For example, we lowered the growth temperature and saw that different genes turned on in response. This helps us learn more about how the genes are functioning in the cell.

From this work, I predicted genes that could affect growth rate, and the genetic engineers are now testing these predictions. Our work on the genomics will help the genetic engineers create better strains, and better strains means higher production and overall lower cost. Each day, we are making steps towards commercialization of algae-based fuels. I am optimistic that soon you will see algae-based biofuels at the gas pump.