There is significant interest in the production of plastics made from renewable resources because they are biodegradable and thus environmentally friendly. Of the 40 billion tons of global production of plastics, bioplastics accounts for only 500 million tons (roughly 1.25%). If their production costs could be halved, the amount of bioplastics produced in 2010 could be trebled (Reverchon, 2002). The main platforms for bioplastic production include the use of microbes, plants and animals to produce desired plastic polymers, and the use of microbes and/or enzymes to convert carbohydrates and/or proteins into desired plastics (The Economist, 2003).
For example, Cargill-Dow Chemical Company employs enzymes to produce Ingeo or Nature Works PLA, a polylactic acid (PLA) product made from glucose. It has commissioned a $300- million plant that can manufacture 140,000 tons of Ingeo, for use mainly in packaging. Similarly, DuPont employs a transgenic bacterium containing biochemical pathways from three different micro-organisms to convert (maize) glucose syrup to 1,3-propandiol, used to manufacture a polyester called Sorona, a copolymer, made from 1, 3-propandiol and terephthalate (oil product).
Some bacteria synthesize and accumulated polyhydroxyalkanoate (PHA), used to make bioplastic, up to 80% of their weight. The firm Metabolix is developing plastics from PHA and has genetically engineered plants to produce PHA. Metabolix planned to start commercial production of PHA by the end of 2003 (The Economist, 2003). There is increasing interest in bioplastic production as it is biodegradable and comes from renewable sources. However, the cost of the final products remains higher than equivalents made from fossil fuels.
