Assessment of Environmental Biodegradation of Synthetic Polymers
The large-scale commercial use of synthetic polymers and their disposal in the environment is a phenomenon less than half a century old, a duration which is minuscule in the evolutionary time scale required for microbial evolution on earth. Consequently, unlike their naturally-occurring counterparts, the biopolymers, which enjoyed long-term interactions with the microbial biosphere, synthetic polymers never had the opportunity to serve as a source of a microbial nutrient of any significance. Hence, few, if any, of the microorganisms are biochemically equipped to catabolize synthetic macromolecules. This lack of development of metabolic pathways capable of utilizing synthetic polymers is often cited as the main reason for recalcitrance of synthetic polymers in the environment . The term “recalcitrant” is used here to describe organic compounds that persist for extended periods of time in the environment, but not necessarily as a result of microbial fallibility.