Polymers protect us from the elements, increase the fuel efficiency of
cars, protect food from pathogens, help cure disease, and enable
renewable-energy technologies. To promote, foster, and enable a
sustainable society, we need polymers. Yet polymers can also create
serious environmental challenges. Nearly all plastic packaging
produced—more than 80 billion kg annually—originates from fossil
resources and is disposed of after a relatively short period of use.
Biodegradable plastics are those that can be completely degraded in
landfills, composters or sewage treatment plants by the action of
naturally occurring micro-organisms. Truly biodegradable plastics leave
no toxic, visible or distinguishable residues following degradation.
Their biodegradability contrasts sharply with most petroleum-based
plastics, which are essentially indestructible in a biological context.
Because of the ubiquitous use of petroleum-based plastics, their
persistence in the environment and their fossil-fuel derivation,
alternatives to these traditional plastics are being explored. Issues
surrounding waste management of traditional and biodegradable polymers
are discussed in the context of reducing environmental pressures and
carbon footprints. Plants naturally
produce numerous polymers, including rubber, starch, cellulose and
storage proteins, all of which have been exploited for biodegradable
plastic production. Bacterial bioreactors fed with renewable resources
from plants--so-called 'white biotechnology'--have also been successful
in producing biodegradable polymers.
Friday, November 17, 2017
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