Microbial degradation of synthetic polymers

Successful processes for the microbial degradation of synthetic polymers began to emerge in 1978. Organisms capable of biodegradation of polyurethane polyester, polyethylene, polyethyleneglycol, polystyrene, polyvinylalcohol, polyacrylonitrile, nylon 3 and nylon 6 were identified. There was a maximum molecular weight for attack and in some cases only oligomers were susceptible. The polymers were converted to biomass or smaller molecules or polymers without certain side groups. The degradation processes should be capable of much improvement by accelerated evolution of the microbial agents in continuous cultures. Co-oxidation of the polymers with another substrate, for example methane, with methane-oxidising bacteria as agents is suggested as a possible degradative means. The insolubility of polymers is a serious barrier to microbial attack and constitutes a major problem for investigation. Ultimately bio-degradation should provide a mild means for the recycling of synthetic polymers with the advantage of greater control over the degree of degradation.