The old guy in The Graduate was right. Plastic was the future. Durable, light, malleable, and cheap, it's everywhere today, from food packaging to toys to computer keyboards. But lately its imperfections have become as apparent as its strengths. It's made from oil, with all the downsides that implies. To achieve its most valued characteristics, it is frequently impregnated with chemicals that have turned out to (1) leach from toys and containers once thought to be inert, and (2) cause developmental defects and possibly cancer (more about this soon). And it doesn't biodegrade, instead lurking for decades in landfills and floating around in the ocean. So a replacement for petro-plastic would solve several problems and find a big, willing market.

One possible solution is to make plastic from plants instead of oil. Today's "bioplastics" are produced in a process similar to that for producing ethanol-by fermenting corn starch and feeding it to specially designed microorganisms that excrete polymers, which are then turned into films, sheets, and fibers, just like petroleum-derived plastic. Because plants sequester carbon when they grow, turning them into plastic puts less carbon into the atmosphere. And bioplastics don't require the dangerous additives that are striking such fear into parents these days. On the minus side, bioplastics can't be recycled along with traditional plastics because they're not compatible. But this is a temporary problem; the recycling industry is working with bioplastic producers to make it easier to tell the two kinds of plastic apart. So as the amount of bioplastic in the marketplace rises, the recycling infrastructure will develop along with it.

Current bioplastics are more expensive than petroleum-based commodity plastics, but they are becoming cost competitive at the high-performance end of the market. They're seeing rising demand in niches like drug capsules, electronics, and car parts. Cargill's NatureWorks joint venture makes a popular corn-based bioplastic that's used in water bottles, among other things. Toyota is building bioplastic plants and intends to make its own auto body parts. And Massachusetts-based Metabolix recently partnered with Archers Daniels Midland to introduce a bioplastic called Mirel that biodegrades in any environment where microbes are present, including soil, industrial or home compost, septic systems, and the ocean. Target stores now offer gift cards made of it. At about 2 billion pounds a year, the high-end plastics market is big enough to offer plenty of near-term growth for newly developed bioplastics. But this generation of bioplastics will never replace oil. As with corn-based ethanol, the fact that they're made from food is a deal breaker, because their popularity drives up prices at the grocery store, penalizing the world's poor and destabilizing the global economy (and raising bioplastic manufacturing costs). But as with biofuels, starting with corn helps build an infrastructure that can adapt to other feedstocks as they become available. Metabolix, for instance, is genetically engineering switchgrass, oil seeds, and sugarcane to produce bioplastic in their cells. Once this becomes possible on a commercial scale, the next step is to set up dual-process bioplastic and biofuels plants. "We'll grow the biomass crops, extract the plastic and use the residual 90 percent as a source of biofuels," says Dr. Oliver Peoples, founder and chief scientific officer of Metabolix. "There's more to be done, but we're way beyond proof of concept.  ....read more