Prof. Avihai Danon of the Weizmann Institute of Science's Department of Plant Sciences has been working with algae—simple, photosynthetic life forms that can be found all over the world—for more than 20 years. Algae are diverse, having many thousands of species, and adaptive, thriving in a variety of conditions; these attributes can teach scientists a lot and make algae, as Prof. Danon says, "a great model system to study." For example, in his research focusing on how they adapt to sunlight, Prof. Danon found that there is a very sophisticated level of regulation inside algae. "On the one hand, the plant utilizes sunlight for energy production through photosynthesis," a process that, while beneficial, must be very carefully calibrated because "on the other hand, it can kill the plant in seconds," he says. He likes to compare a plant's ability to perform photosynthesis to having an atomic reactor in your stomach: the reactor can provide you with free energy, but if it's not tightly controlled, then it can explode.
In current research, Prof. Danon, in a cross-discipline collaboration with Prof. Uri Pick of the Department of Biological Chemistry, has been studying another virtue of this tiny but powerful plant: as a source of fuel. The team's project is part of the Weizmann Institute's Alternative Energy Research Initiative, or AERI, established in 2006 with the goal of actively expanding research efforts toward the scientific and technological advances necessary for keeping our planet livable. Algae have several advantages over other sources of biofuel (fuel produced from vegetable oils or animal fats); for example, they grow very quickly, and can be cultivated in saltwater, marshlands, and other places where they won't compete with food crops.
Scientists had observed that under certain stress conditions, some micro-algae accumulate large amounts of triglycerides. Triglycerides are the chief building-blocks of fats and oils, and function to store chemical energy in plants and animals. By growing and harvesting the algae, then extracting and chemically processing the triglycerides, industry may be able to mass-produce a biodiesel that can be used to power vehicles and aircraft and heat homes and other buildings. Because such fuel can be used in diesel engines, Prof. Danon says "it doesn't have to change the car industry" in the same way that, for example, hydrogen fuel would. The ability to use existing infrastructure and engines is generally considered critical for widespread adoption of new fuels.
Given what was known about algae's potential, Profs. Danon and Pick felt that if they could increase the ability of microalgae, via genetic engineering, to produce triglycerides in greater quantities, they could render it a viable source for biodiesel fuel. To that end, they have undertaken a massive genetic screening project to identify the elements controlling triglyceride accumulation in micro-algae. Prof. Danon indicates that his goals in this endeavor are twofold: gathering critical information and finding practical solutions. With regard to the first, he says, "the research will provide very important basic information about the regulation of oil biosynthesis in algae. What are the signals? What are the molecules that accept the signals and translate them into commands?" In terms of the second goal, "we can get the genes that, for example, increase oil production in algae, which is very practical. We will then be able to say something like, ‘If you use these four genes, they will increase oil production by this much."
Achieving these aims is no easy feat. After manually screening several thousands of variants, the team identified one gene that confers higher triglyceride accumulation. In order to speed up the process, a high-throughput robotic system, funded by contributions from devoted Weizmann donors, has been put to the task of screening. "The purpose of the robotic system is to identify all the genes involved in regulating oil production," says Prof. Danon. "Up until now we did the screening manually, and we were able to perfect the method and identify a single gene, but in order to identify all potential genes, we have to go through what is probably close to 100,000 variants. What we could do in 10 years manually, we will be able to do in perhaps six months with the robot."
While Prof. Danon examines ways of increasing triglyceride production on a genetic level, Prof. Pick characterizes the regulation system that controls such production, and searches for possible candidates for the regulation of triglyceride accumulation. By combining their expertise, the scientists hope to both identify the key proteins controlling triglyceride production and the genes that express them.
Prof. Danon reminds us that algae did not evolve to satisfy the fuel production needs of humankind, and that there are still many questions to be answered and obstacles to overcome. However, he does believe that through creative research, perseverance, and innovation, and with the help of advanced technology, these tiny, simple plants may one day serve as a powerful alternative fuel source.
Prof. Avihai Danon's research is supported by the Brazil – Israel Alternative Energy Research Fund; the Jack and Elisa Klein Foundation; Jack N. Halpern, New York, NY; and Daniel S. Shapiro, UK. Prof. Danon is the incumbent of the Henry & Bertha Benson Professorial Chair.
