Agriculture Secretary Tom Vilsack, left, visited Boston-area start-up Agrivida last week to tour the biotech company's lab. Agrivida has received grant money from the Departments of Agriculture and Energy to research a method of speeding up biofuel production from non-food plants. Its technique is to isolate and insert specific genes into plants that break down the cellulose in the cell walls of sorghum and corn stover, the residue from corn harvesting. To sift through the hundreds of thousands of enzymes scientists are trying to isolate, it uses this robot to rapidly scan different enzymes. Showing him how it operates is Agrivida biochemist Taran Shilling.
Once enzymes are isolated, they are dyed in assay plates such as this one. The dye is used to indicate how long the enzymes live. Agrivida has processed 600,000 enzymes this year and more than 2 million in the past few years. So far it has genetically engineered 10 enzymes. "It's a big numbers game," said CEO Mark Wong.
Once specific enzymes are chosen, they are grown in a type of bacteria that can be incubated and then introduced into plant cells. The plants then grow with enzymes in them in a dormant state. To activate the cellulose-chopping function in plants, Agrivida is developing another enzyme that will act as a "switch." The switch is activated after harvest by exposing plants to high temperatures or through other methods.
Once the genes are transferred into plants, Agrivida technicians grow these transgenic plants in the lab. Growing the proteins in the plant allows them to test the effectiveness of their process. The company has a larger greenhouse facility as well. Testing the genetic traits in plants, rather than in micro-organisms, gives researchers an accurate idea of how the enzymes will operate in the field.
In the final stage done here, different strains of plants are tested for their ability make sugars. In some tests, Agrivida has found that its process can improve the sugar output by 50 percent compared to traditional cellulosic ethanol processes. Those sugars are then fermented to make ethanol or converted into other fuels and specialty chemicals. Here an Agrivida employee explains the technology to Agriculture Secretary Tom Vilsack (on left).