PhD candidates love research – and each other

cabnr graduate studentsAs the driest state in the country, Nevada might not seem a likely place to solve some of the nation's most pressing needs for natural rubber and biofuel. Rubber trees grow in the rainforest, right? Biofuel like ethanol needs millions of acres of corn, right?
Well, not necessarily.
Two Ph.D. candidates from the biochemistry department of CABNR have made remarkable inroads into both of these critical questions - all while raising a family and working with plants readily available in the Silver State.
Upul and Leyla Hathwaik met when they were both undergraduates in biochemistry at UNR and were married seven years ago. They both finished work on their respective Ph.D.s with CABNR in late 2012, and now are looking for post-doctoral positions as they await the arrival of their second child.
Upul, 35, was considering going to medical school when he took a job as a lab assistant with David Shintani, now the Associate Dean of Resident Instruction at CABNR, and quickly realized he loved being in the lab. So he decided he would focus on research.
Since then, he has concentrated on analyzing the potential of rabbitbrush as a source of natural rubber. Rabbitbrush - the desert plant that blooms in the fall and often triggers allergic reactions as its yellow flowers blossom - is fairly common in Nevada. But most people don't realize that rabbitbrush produces a high-quality rubber that has several physical properties analogous to existing commercial natural rubber producers.
Natural rubber is produced from the latex tapped from rubber trees (Hevea brasiliensis) in South Asia. Right now, these trees are the sole source of natural rubber in the world, and 90 percent of the trees are located on plantations in five South Asian countries. The rubber is used in more than 40,000 products - from tires to medical instruments - and in 2011 the United States spent $4.4 billion importing natural rubber. Researchers have never been successful in designing a synthetic product with the same characteristics of natural rubber.
What's more, the biosynthetic pathway that produces natural rubber has also never been fully understood, and that has become another major avenue of Upul's research.
Upul and Shintani began collecting and analyzing rabbitbrush samples from around Nevada in 2006 and ultimately found that some of the best rubber was produced in rabbitbrush on Gund Ranch near Austin. Surprisingly, the better samples came from smaller plants living in areas with little water and poor soils.
More research is needed, Upul stressed, before rabbitbrush can become a domestic rubber supplier. But work is also under way to further analyze the commercial potential of rabbitbrush resin as well as the biomass residue left after rubber extraction.
"We think it eventually could become a domestic source of rubber, and if that happens, we would be less dependent on imports," he says. "Demand for rubber is increasing, but the supply is not."
Leyla, meanwhile, has been at work in the lab of CABNR's Prof. John Cushman, studying the potential for using microalgal culture to produce biofuels.
"Microalgae are high in oil and starch," Leyla says, "so we're looking at them as useful feedstocks for biofuel production."
Much of her work has focused on developing methods for selecting, identifying and improving microalgae stains with enhanced lipid or starch content. One method involved using continuous Percoll buoyant density gradient centrifugation to isolate cells with higher lipid or starch content. The second approach utilized Fluorescent Activated Cell Sorting to find and isolate those microalgae cells with high oil and starch content. Leyla also worked with a plastome transformation method to genetically improve feedstock traits.
"It's going to be a long process for this to be commercially available and affordable," Leyla says.
"But companies are putting a lot of effort into getting us there and maybe in the future we'll have a product from microalgae that can be blended with gasoline as a form of fuel."
 Leyla originally worked on understanding the evolutionary origins of Crassulacean acid metabolism, a mode of photosynthesis, in orchids, but when Cushman got a grant to work on microalgae as a fuel source, she fell in love with that work.
"We need to find an alternative source of fuel, and I think this would be a good one," she says.