If you pay any attention to headlines about alternative energy, you know by now that our two big problems with transportation fuels — our dependence on foreign oil produced by people who hate us and the greenhouse-gas emissions — could be solved, at least in part, by biofuels. They can be home-grown, and the heat-trapping carbon dioxide they pump into the atmosphere is balanced by the CO2 they sucked out of the air while they were growing. Unfortunately, nobody’s figured out how to turn biofuels into a true replacement for diesel and gasoline, for a variety of reasons.
But a Princeton University senior named Amanda Rees may have come up with the most promising solution so far. Rees, 22, is convinced that an important part to the world’s energy future may lie in a fast-growing, nearly indestructible weed that makes homeowners tremble and pandas salivate: bamboo. “It comes in over 1,200 species,” she said with unabashed enthusiasm during a conversation in her lab, deep within Princeton’s Engineering Quadrangle. “It has a high growth rate, and it thrives in thrives in a wide range of climates.”
Best of all, she explained, bamboo is so hardy — it’s downright, aggressive, in fact — that you can grow it in places that wouldn’t be suitable for food crops. It was that concern that first got her into the bamboo game. “I’ve been really passionate about the environment ever since high school,” she said. The school was Marlborough, in Los Angeles, a private girls’ school that has a program focused on getting students internships in science labs. Rees interned at UCLA for two years, focusing on materials science projects, including finding ways to store hydrogen as a future energy source.
ON THE FRONT LINES
Antonio Busalacchi: Climate Scientist and Certified Specialist of Spirits
Keith London: City commissioner, Hallandale Beach, Fla.
Katharine Hayhoe: Climate scientist and professor at Texas Tech University
Abigail Borah: 21-year-old Middlebury junior
Edward Lu: Astrophysicist and electrical engineer
Michael Mann: Climatologist and physicist
When she arrived at Princeton, Rees knew she wanted be an engineer, but yet another summer internship, this one at Stanford’s Woods Institute for the Environment, left her with a real concern about food security. In the U.S., she said, “we’re now using more corn to make ethanol than we are for food” — a trend that drives up the price of both. “Does that really make sense?” It even makes less sense when you realize that corn ethanol may be little better for the climate than gasoline, and maybe even somewhat worse.
In trying to figure out what she’d do for her senior thesis project, Rees and her advisor, engineering professor Winston Soboyejo, went back and forth on a few ideas and finally realized that her interest in energy and food security dovetailed with one of his. “He really loves bamboo,” she said. Sobojeyo has designed pack frames for camels made of the light, strong, inexpensive stuff, and guided students in building a bamboo bicycle.
People had tried converting bamboo into ethanol before, but Soboyejo urged Rees to explore the idea of making it into butanol instead. Like ethanol, butanol is a form of alcohol, but, where ethanol is corrosive to pipes and engines in too high a concentration, butanol isn’t: you can therefore mix more of it with gasoline. “It also has a higher energy density,” Rees said, “and when you burn it, it creates less nitrous oxide and sulfur in the exhaust.”
The tricky part is that where ethanol can be fermented in open vats, the microbes that naturally produce butanol can survive only in oxygen-free environments. “A few companies are producing it,” she said, “including Butamax and gevo,” but as far as Rees knows, nobody’s making it from bamboo. “Our argument is that we’re using a better feedstock to create a better fuel; we’re capitalizing on the advantages of both.”
Since the engineering school isn’t equipped with the fermenters that you need to cook butanol, Rees also had to collaborate with faculty in Princeton’s molecular biology department. “We know about chemistry,” said Rees, a chemical and biological engineering major, “but they’re the experts on bacteria.” Rees liberated the bamboo’s internal sugars by treating bamboo sawdust acid and enzymes, but bacteria she used to try and convert the sugers into butanol only produced a small amount of fuel. The process clearly needs to be improved on to be commercially useful — possibly by trying a different bacterial species.
Will Rees be the one to do the improving? She’s not sure. “I’ve thought about staying on after graduation to do another year of research. I’ll probably go to grad school eventually.”
But for a young woman with such wide-ranging interests, it may be too early to focus narrowly on the most obvious career path. Last year, Rees was named a Dalai Lama Fellow, a distinction that allowed her to pursue a project designed to further compassion and understanding.
“My project,” she said, “was going to an all girls’ school in Tanzania, “where I taught a class on energy, the environment and entrepreneurship. The girls were brilliant, just amazing. It was life-changing.”
It’s a pretty safe bet that those Tanzanian girls felt exactly the same way about her.
OPB | Feb. 22, 2017