Feature: Farm Fields of Dreams
FARM FIELDS OF DREAMS
In a major scientific breakthrough, MSU researchers have discovered how to produce plastics from plants--a process that has staggering economic and environmental benefits. In Chris Somerville's dreams, there are many fields. They look like ordinary farm fields full of corn, potatoes, sunflowers and other crops. But they're not producing food. They're making plastics and epoxies and industrial oils such as palm, coconut and castor. Such products are now imported from tropical countries or derived from non-renewable sources. But in the dreams of this MSU plant scientist, they are all being grown from crops by farmers in Michigan and other states. These are pleasant dreams in which the United States reduces its imports and American farmers no longer have to be paid to take land out of production.
Fortunately, Somerville, 44, has already shown that he is more than a dreamer. In a milestone scientific paper published in Science in April, Somerville and colleagues gained international media attention by reporting they had added genes to a test plant to make it produce a biodegradable plastic. This is real, commercially valuable plastic--a type called PHB for polyhydroxybutyrate. It's similar to polypropylene and can be used for containers, for disposable diaper liners, for food wraps and many other purposes. But, unlike polypropylene, it doesn't last long in the environment. Leave it to nature and it will degrade just like wood, leaves or paper. Also, it isn't made from petroleum, so it's a renewable resource. PHB is naturally produced by certain soil bacteria. A British company called Imperial Chemical Industries has been growing these bacteria in huge vats in order to produce this plastic on a commercial scale. Imperial does this even though the PHB plastic it produces costs $12 a pound as compared to about $.50 a pound for plastics derived from petroleum. Even at that price, Imperial says it can't meet demand.
Customers--Wella Shampoo, for example--pay extra because of public demand for biodegradable products. But, according to Dr. Somerville, the cost of PHB can be reduced to as little as one-tenth its present cost by growing it in plants. And that is why he and colleagues attempted--and succeeded in--transferring genes for making PHB from soil bacteria into a test plant. This test plant, called Arabidopsis (a-RAB-i-dop-sis), a weed of the mustard family, is proof that plants can produce PHB. However, Arabidopsis is worthless as a commercial producer. Still, the accomplishment is only a beginning, says Somerville. 'We're now making only relatively small amounts in Arabidopsis--only about one-third of one percent by weight. We didn't make any attempt to maximize it. We only wanted to see if it was possible. 'But once you know something is possible, you can go about it in an orderly fashion. And so can many other people in other laboratories.'
Industrial resources will soon be accelerating the pace of development. To bring this about, MSU applied for a patent on the gene-transfer process and is negotiating a licensing agreement with a major corporation. The next steps--all of which are feasible to today's biotechnologists--are to put it into a commercially grown crop plant. Likely candidates are potatoes, |sugar beets and turnips -- plants that now make a lot of starch and store it away. 'Our goal,' says Somerville, 'is take a plant that normally accumulates a lot of starch and metabolically restructure it so that the carbon that would normally go into the starch will now go into this plastic.'
Getting it into other plants in commercially viable quantities is probably ten years away. Still, that means one of Somerville's dream fields could be reality early in the twenty-first century. Plants as Oil Producers Some of Somerville's other dream fields may not be far behind. He and MSU colleagues John Ohlrogge, Jack Priess and N. Edward Tolbert formed the MSU Plant Science Center in 1988. The center is funded by three federal agencies--Dept. of Agriculture, Dept. of Energy and the National Science Foundation. The center's goal is to find ways of modifying American crops to produce some of the billions of dollars worth of non-food products that are now imported from tropical countries or made by chemical companies. 'For example,' says Ohlrogge, 'U.S. chemical manufacturers now import about 600,000 tons a year of coconut and palm oils. They are what chemists call `12-carbon fatty acids'--oils that are not produced by any U.S. field crops.'
Although several oils are being considered and worked with, one of the prime candidates is castor oil. Although it is most commonly known as a laxative, castor oil is a high-quality, high-temperature lubricant widely used in industry and jet aircraft. It is also used to produce a type of nylon. 'The difference between the oils we import and the oils that American farmers produce is a small difference in chemistry,' adds Somerville. 'If we can understand the biochemistry of how these plants make oils, we can re-engineer them so that we can produce these oils on our farms.'
By giving American crops the capacity for making these oils, the scientists would enable American farmers to keep growing crops they know how to grow and radically increase their productive potential. 'It always struck me as ridiculous that at a time when we are paying farmers to hold land out of production we are importing $1 billion a year worth of agricultural products from other countries,' says Somerville. 'That $1 billion is 20,000 American jobs.'
The MSU researchers are not alone in their efforts. Biotechnology companies as well as other university laboratories are very active. However, Somerville and Ohlrogge believe they have the major center in the world for research on the genetic engineering of plant oils. Accordingly, they are currently organizing a consortium of like-minded laboratories to share information and coordinate efforts.
PLANTS AS CHEMICAL PLANTS
These dreams aren't fantasies, but to understand why they aren't, it helps to think of crop plants as chemical factories ('industrial plants,' if you want to be punny). They take in water, oxygen, nitrogen, carbon and other simple, basic chemicals. They move them about and hook them together in various ways to produce a wide variety of complex chemicals--proteins, oils, sugars, starches, cellulose, latex and turpentine, for example. In these living chemical factories, the bosses are the genes. They direct the conveyor belts and all the mixing and catalytic reactions that take place. But unlike human bosses, genes have no free will or versatility. To change the end product, you have to delete, add or alter a gene.
The genetic engineering techniques for doing this are steadily becoming more routine in laboratories throughout the world. New 'transgenic' plants in the laboratory are now almost commonplace. Because it is very difficult to add or alter more than one gene, biotechnologists seek out single genes that can make a big and commercially viable difference. Changes to date have been relatively small, usually involving only one gene, but enough to make better-tasting tomatoes and enable some crops to resist frost and disease. The work of Somerville and colleagues is remarkable because three genes were involved.
