Ancient Algae: Genetically Engineering a Path to New Energy Sources?

Botryococcus braunii, Race B, is an ancient, colony-forming green alga that has attracted interest because it accumulates large amounts of high-value, petrochemical replacement oils. The oil oozing from the algal colony is evident in this picture. (Credit: Photograph courtesy of Taylor Weiss, Andreas Holzenburg, Stanislav Vitha and Timothy P. Devarenne at Texas A&M University)

Science Daily — A team of researchers led by University of Kentucky College of Agriculture Professor Joe Chappell is making a connection between prehistoric times and the present -- ancient algae that can produce their own biofuel -- that could result in genetically creating a replacement for oil and coal shale deposits. Their discovery could have fundamental implications for the future of Earth's energy supplies.

While scientists previously established that oil and coal have their roots in the organisms that lived on the planet over 500 million years ago, one micro-organism directly contributed to these natural resources. That organism is a species of algae calledBotryococcus braunii, which left behind its chemical fingerprints -- an oil that over geological time has turned into oil and coal shale deposits.

Tom Niehaus, completing his doctorate in the Chappell laboratory; Shigeru Okada, a sabbatical professor from the aquatic biosciences department at the University of Tokyo; Tim Devarenne, a UK graduate and now professor of biochemistry and biophysics at Texas A&M University; and UK colleagues, Chappell, David Watt, professor of cellular and molecular biochemistry (College of Medicine) and his post-doctoral associate Vitaliy Sviripa report their latest research in the Proceedings of the National Academy of Sciences (PNAS). Their findings go well beyond the basic science dealing with the origins of oil and coal.

"Even more exciting is that this unique alga, B. braunii, still exists today and has been the target of studies from the large chemical and petrochemical industries," said Chappell.

B. braunii are very slow growing algae, so the organism is not necessarily a good source for biofuels. However, if scientists can capture its genetic blueprints for the biosynthesis of these high value oils, then these genes could be used to generate alternative production platforms.

This team of investigators isolated the necessary genes, characterized the biochemical traits encoded by these genes, and then genetically engineered yeast to produce this very high-value oil. This work has provided the first example of recreating a true direct replacement for oil and coal shale deposits.

Chappell said, "This represents the culmination of an outstanding effort to understand a fundamental process that has direct ramifications for a real-world problem -- how are we going to generate a truly renewable biofuel supply?"

Devarenne added, "This study identifies a very remarkable molecular mechanism for the production of hydrocarbons that, as far as we can tell, is not found in any other organism. Thus, it offers a unique insight into how hydrocarbons were produced hundreds of millions of years ago."