AgriLife scientists sequence genome of microalga that can produce fuels

Three jars containing a green liquid

Image: Texas A&M AgriLife Research

The genome of the fuel-producing green microalga Botryococcus braunii has been sequenced by a team of researchers led by a group at Texas A&M AgriLife Research.

The report, published in Genome Announcements, comes after almost seven years of research, according to Tim Devarenne, an associate professor in the Department of Biochemistry and Biophysics, an AgriLife Research biochemist and a principal investigator in College Station. In addition to sequencing the genome, other genetic facts emerged that ultimately could help his team and others studying this green microalga further research toward producing algae and plants as a renewable fuel source.

“This alga is colony-forming, which means that a lot of individual cells grow to form a colony. These cells make lots of hydrocarbons and then export them into an extracellular matrix for storage,” Devarenne said. “And these hydrocarbons can be converted into fuels – gasoline, kerosene and diesel, for example, the same way that one converts petroleum into these fuels.”

Devarenne pointed to previous studies showing that hydrocarbons from B. braunii have long been associated with petroleum deposits, indicating that over geologic time the alga has coincided with and contributed to the formation of petroleum deposits.

“Essentially, if we were to use the hydrocarbon oils from this alga to be a renewable fuel source, there would be no need to change any kind of infrastructure for making the fuel. It could be put right into the existing petroleum processing system and get the same fuels out of it,” he said.

Devarenne said his lab wants to understand not so much how to make fuel, but rather how the alga makes these hydrocarbons, what genes and enzymes are involved and how they function.

“Once we understand that, maybe we can manipulate the alga to make more oil or specific types of oil or maybe we can transfer those genes into other photosynthetic organisms to have them make the oil instead of the alga,” said Devarenne, whose lab in 2016 announced the discovery of the enzyme used by the algae to produce hydrocarbons.

That’s why sequencing the genome was important, he said, because it will help identify all the genes and enzymes in the genome needed for hydrocarbon production and control of this production.

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