Exploring the Pathways Underlying Tomorrow's Green Biofuel

To unlock the potential of algae as a viable source to power the vehicles of the future, scientists and engineers must first decipher the inner mechanisms of the tiny organisms. Marine algae are some of the planet's most productive organisms and generate oils that could energize tomorrow's clean biofuel.

Scientists at Scripps Institution of Oceanography at UC San Diego came a step closer to understanding these underlying processes recently with the publication of a scientific study of marine algae known as diatoms and the inner production pathways responsible for the oils they generate known as lipids.

The study was published in the inaugural edition of Algal Research, a journal launched in April featuring peer-reviewed findings in the rising field of algal science.

The new journal's first paper, led by Scripps graduate student Sarah Smith in marine biologist Mark Hildebrand's laboratory, analyzed methods and pathways that diatoms use to process carbon, also known as "carbon partitioning," a key to their oil production.

The biochemical processes behind these pathways is not well understood, partly because the evolutionary history of algae is different from more traditional model organisms.

"We don't know a lot about these pathways or even the basic biology," said Smith, who likened them to valves directing water flow. "And that makes it particularly challenging when selecting the targets that are appropriate for engineering future biofuel production."

Smith says such basic biological investigations will provide information to make algal biofuel production more feasible and economical.

Smith, fellow Scripps student Raffaela Abbriano, and Hildebrand capitalized on decoded genomes of three diatoms to compare carbon partitioning pathways. Mining this genetic data, Smith said, might allow researchers to construct a central "blueprint" for physiological targets. However the researchers found that even close relatives of diatom species feature distinctly modified carbon partitioning pathways-likely evolutionary adaptations for different environmental niches-and in fact have features organized unlike any other organisms on Earth.

The new analysis, the researchers say, "highlights how even core central pathways can be modified considerably within a single algal group, and enables the identification of suitable targets for genetic engineering to enhance biofuel precursor production." The analysis has already been put to use in approaches to improve productivity in the lab.

Sequence data used in the study were produced by the U.S. Department of Energy (DOE) Joint Genome Institute. Other supporters of the study included the Air Force Office of Scientific Research, DOE, National Science Foundation, Department of Defense through the National Defense Science & Engineering Graduate Fellowship Program, and the San Diego Fellowship through the UC San Diego Temporal Dynamics of Learning Center.