Algae and Light: the Foundation for Her Life’s Work

Dr. Mautusi Mitra is setting up for her life’s work.

Her foundation research project is in a laboratory in UWG’s Biology building, where single-cell algae are subjected to varying growth conditions.

Some algae are grown as liquid cultures in flasks on shakers or on solid media culture plates—small rounds discs.

Key to Dr. Mitra’s work is how much light the cultures receive.

Some cultures grow under very high light conditions. A fan blows continuously so that they don’t overheat. Others grow in medium light or very low light conditions.

Still others grow in complete darkness on culture plates containing vinegar. The small discs are wrapped in aluminum foil. In the darkness, these algae will behave like a green fungus and continue to develop, Dr. Mitra explained, as she peeled away the foil wrapping of one of the culture plates.

The algae inside were green. Instead of light, the algae used the vinegar as a carbon source.

“It’s not doing photosynthesis. There’s no sunlight to help it to grow and they stay green,” she said, her voice rising with excitement.

“But it can still use that acetic acid (vinegar) in the medium. It uses that as carbon source to make sugar. Photosynthesis’ job is to trap carbon dioxide and convert it to make sugar in the presence of light, water and a green pigment called chlorophyll.”

Compared to higher plants the alga is unique because it can use vinegar to grow in the dark and to stay green, Dr. Mitra explained. In the light it can also use carbon dioxide in the atmosphere to make sugar during photosynthesis.

Her “babies” are called Chlamydomonas reinhardtii – Chlamy for short. Dr. Mitra and her students have generated different mutants of this alga. They keep a close watch on these mutant strains.

They are studying photosynthesis at its most fundamental levels. What they learn could ultimately impact the development of green bio-fuels and have applications in agriculture.

Among the first things they did to begin the work was insert a string of artificial DNA, whose entire sequence is known, into the algal cells. The algal cells grew on culture plates and each colony in the plates is a mutant clone.

Later, Dr. Mitra will look for which genes have been “knocked off” or silenced by the piece of DNA in the mutants. These mutant algae are the foundations of her “mutant library,” which will help her identify the genes and proteins that play a role in photosynthesis.

She is looking for the genes that are:

• Defective in sensing light intensities
• Are sensitive to high light and harmful oxygen ions and radicals, damage proteins, lipids and DNA inside the cell
• Are deficient in the pigments that trap sunlight
• Cannot make the necessary adjustments to perform photosynthesis efficiently.

“This is hard core research that I’m doing,” she said. “It takes time to build up a new research project. This is what I’m doing to build the foundation in my research career in academics.”

Recently, the Provost and Vice President for Academic Affairs awarded Dr. Mitra a summer seed grant of $10,778 to support her research project.

“My research will help to advance knowledge in the field of plant molecular biology,” she said. “This is a huge field. [Photosynthesis] is the only reaction on this planet that can give you oxygen. It’s a fundamental chemical reaction on this planet. There is no other way you can get oxygen that you breathe in. So it is very, very important.”

Before coming to UWG, Dr. Mitra was a post-doctoral research scholar at the University of California, Berkeley. She earned her Ph.D. at Louisiana State University.

She holds a patent with Dr. Anastasios Melis, a professor at Berkeley’s Department of Plant and Microbial Biology. Two biotech companies in California have purchased the research patent for its application to biomass production.

At Berkeley, Dr. Mitra and Dr. Melis, who was her postdoctoral research supervisor, studied the same strain of algae (Chlamydomonas reinhardtii) and the genes that regulate chlorophyll antenna size. In photosynthesis, the antenna trap sunlight and convert the solar energy into biomass.

The patent they developed identified TLA1, the gene that plays a role in making the chlorophyll antenna sizes smaller. Smaller antenna allows sunlight to reach all of the layers of algae efficiently in a bio-reaction. This improves the solar conversion in photosynthesis.

The breakthrough has applications in improving the productivity of algal strains used in the development of green bio-fuels and other plant-based commercial products like vitamins, carotenoids and other health supplements.

Essentially, with her research Dr. Mitra is learning how to “make better use of sunlight,” she said.

Do you have a comment or opinion about this story's topic? Send your thoughts to West Georgia Voices.