Filed by Steve Ritter
After a three-hour ride from the airport and checking into our hotel in São Carlos, we wasted no time in getting started with our tour by visiting EMBRAPA Instrumentação Agropecuária. You have to love these Portuguese spellings.
EMBRAPA, which stands for the Brazilian Agricultural Research Corp., is Brazil’s equivalent to the U.S. Department of Agriculture. It has some 40 research centers spread around the country, and the Agricultural Instrumentation Center, located in São Carlos, does just what its name implies: The center develops analytical methods and instrumentation for agricultural research.
Several members of the U.S. delegation and several EMBRAPA scientists presented brief overviews of their research, and then we toured the lab facilities. One project I found particularly interesting is a high-throughput nuclear magnetic resonance spectroscopy technique developed by EMBRAPA’s Luiz Alberto Colnago and colleagues to monitor the oil content of plant seeds. This nondestructive screening method, based on continuous-wave free-precession NMR, gives a proton NMR snapshot of individual seeds (Anal. Chem. 2007, 79, 1271).
SPEEDY SEEDS Colnago, right, excitedly explains how high-throughput NMR screening of oil seeds works. He holds a tray loaded with seeds that is slid through the NMR magnet to determine oil content of individual seeds. From left in the photo are William R. Sutterlin of Renewable Alternatives, in Columbia, Mo.; Foster Agblevor of Virginia Tech, and EMBRAPA Agricultural Instrumentation Director Álvaro Macedo da Silva.
The straightforward analysis is carried out by sliding a narrow tray loaded with seeds held in individual compartments through a standard magnetic resonance imaging (MRI) magnet. And it’s fast. Colnago showed data for 96 seeds analyzed in 14 seconds—which equates to 20,000 seeds per hour!
Why does one want such high-speed seed analysis? “Two challenges we face are oil-seed productivity and oil quality,” Colnago explains. One way to determine those is low-resolution NMR of each individual seed—the amplitude of the signal from the instrument gives a good indication of a seed’s oil content.
EMBRAPA researchers may want to analyze 100 seeds from a single plant or groups of seeds from different parts of the same plant, Colnago says. In addition, the researchers might analyze seeds from different plants in a field, plants from different fields, and plants from different farms. That ends up being a lot of seeds, he adds.
For the Brazilian scientists, the goal is to selectively breed plants to boost oil production per acre in order to enhance biodiesel output. Colnago and coworkers have analyzed soybeans, cotton seeds, sunflower seeds, rape seeds (canola), castor beans, macadamia nuts, peanuts, sesame seeds, and others. Most of these examples produce less than 0.5 ton of oil per acre per year, he says.
Palm seeds by far have the highest oil content and quality (highest oleic acid content), which is six to 12 times greater than soybeans. But there’s a tradeoff, as palms take longer to get established before the seeds can be harvested, and biodiesel made from pure palm oil has a high melting point, so it can’t be used at low temperatures.
We witnessed this today by seeing a 5-L container of palm biodiesel that was solid first thing in the morning (about 50 oF) but was liquid once it warmed up. (It is fall heading into winter here.) The difference in the palm and soy biodiesel is the different lengths and the number of double bonds in the long hydrocarbon fatty acid chains that make up the oil. Despite the temperature issue, palm biodiesel is still being pursued because it can be blended with biodiesel produced from other oil seeds, such as soybeans.
To plant seeds with the highest oil content or highest oil quality, the nondestructive NMR method is important, as seeds from subsequent generations of plants can be analyzed and selected. The selective breeding, coupled with genetic modification of plants, will eventually lead to higher producing varieties of oil-seed plants and, in the future, a better situation for Brazil’s biodiesel industry, Colnago points out. The goal is to produce 1 ton of oil per acre per year within the next 10 years and more than 2 tons per acre per year within 30 years, he says.