Inside the alga’s cells, showing the nucleus (purple), mitochondria (red), chloroplast (green) and lipids (yellow). Credit: Melissa Roth/HHMI and Andreas Walters/Berkeley Lab

Scientists have learned in the past decade that the tiny, single-celled alga Chromochloris zofingiensis could be used as a source of sustainable biofuel and that it produces astaxanthin. In new research, plant biologists and biochemists from UCLA, UC Berkeley and UC San Francisco have sequenced the green alga’s genome, potentially an important step toward improving production of astaxanthin by algae, and engineering its production in plants and other organisms.

The study is published online in the journal Proceedings of the National Academy of Sciences.

Chromochloris zofingiensis is one of the most prolific producers of a type of lipid called triacylglycerol, used in producing biofuels. Knowing the genome is like having a “dictionary” of the alga’s approximately 15,000 genes, said co-senior author Sabeeha Merchant, a UCLA professor of biochemistry. “From there, researchers can learn how to put the ‘words’ and ‘sentences’ together, and to target our research on important subsets of genes.”

The study also revealed that an enzyme called beta-ketolase is a critical component in the production of astaxanthin.

Harnessing C. zofingiensis as a source for renewable and sustainable biofuels could lead to new ways to produce clean energy, said Krishna Niyogi, co-senior author of the paper and a scientist at the Department of Energy’s Lawrence Berkeley National Laboratory. Drs. Merchant, Niyogi and Matteo Pellegrini, a UCLA professor of molecular, cell and developmental biology and a co-author of the study, maintain a website that shares a wealth of information about the alga’s genome.

During the study, the scientists also used soft X-ray tomography, a technique similar to a CT scan, to get a 3-D view of the algae cells which gave them more detailed insights about their biology.

Dr. Niyogi is also a UC Berkeley professor of plant and microbial biology and a Howard Hughes Medical Institute Investigator. The study’s other authors are researchers Shawn Cokus and Sean Gallaher and postdoctoral scholar David Lopez, all of UCLA; postdoctoral fellow Melissa Roth, and graduate students Erika Erickson, Benjamin Endelman and Daniel Westcott, all of Dr. Niyogi’s laboratory; and Carolyn Larabell, a professor of anatomy, and researcher Andreas Walter, both of UC San Francisco.

The research was funded by the Department of Energy’s Office of Science, the Department of Agriculture’s National Institute of Food and Agriculture, the National Institute of General Medical Sciences of the National Institutes of Health, and the Gordon and Betty Moore Foundation.