This is slightly old news, as BoingBoing mentioned it last week, but it's very world-changing: Cornell chemists have invented a plastic made from orange rinds and CO2. As the Cornell University News Service reports, the researchers' breakthrough was developing a catalyst that makes an oil extracted from orange rinds (which is currently used for things like "giving household cleaners their citrus scent") react with carbon dioxide to form a polymer. The resulting polymer is similar to polystyrene--not usable for structural applications like PVC, but good for packaging and cloth-fibers.
They do not mention whether the plastic will be biodegradable (and this is not a given--some nylon is made primarily out of castor bean oil, and is not biodegradable), but even if not, it's a potential reduction of oil-dependence and sequesters CO2 at the same time. As Prof. Geoffrey Coates, the team leader, said: "If you can get away from using oil and instead use readily abundant, renewable and cheap resources, then that's something we need to investigate."
I was under the impression that the citrus scented stuff (liminol?) in cleaning based products was actually a very powerful surfactant. I know that the bicycle degreaser I use is made from citrus product and is extremely effective.
Limonene doesn't have the amphiphilicity necessary for it to be a surfactant, but as a hydrocarbon it is no surprise that it is quite effective for grease removal.
Coates is a good dude and is doing an excellent job on the plastic problem on multiple fronts.