There are two main types of bio-polymers:
Cyclodextrin and PHB


Biopolymers are polymers that are made in large by living organisms. Biopol is the commercial name of one such biopolymer formed from the monomers 3-hydroxybutyrate and 3-hydroxyvalerate.

Formation of PHB

By fostering the growth of bacteria cupriavidus metallidurans (alcaligenes eutrophus) in a high glucose, high valeric acid environment and then creating a nitrogen deficiency, the bacteria begin to store carbon in the desired 3-HB/3-HV co-polymer form. The polymer can then be isolated and extracted through the use of hot trichloromethane. This process is quite expensive and so, more recent developments in genetic engineering has provided alternate pathways for the synthesis of Biopol. The production of Biopol by genetically engineered E.coli has seen benefits over the previous process such as polypropelene and also produces pungent waste that is difficult to dispose.
Nevertheless, Biopol does have ideal properties that have seen its application in areas where there resistant and is biodegradable, biocompatible and is produced from a renewable resource.These properties make Biopol an ideal substance for use in the medical industry as well as the commercial marketing of nappy linings. Nappies would be biodegradable and surgical pins and sutures are often made from biopol as it isn't rejected by the body for the majority of the time and is safely broken down in the body (being biodegradable). The stiff and brittle nature of Biopol has been applied to bottles, laminated foils, fishnets and textile fibres.
Overall, it is clear that Biopol has both advantages and disadvantages over conventional polymers, but with ever depleting fossil fuel reserves the demand for alternatives such as Biopol can only increase. Since 2001, bio-technology development corporation Metabolix has been producing Biopol by microbial conversion of natural sugars and is developing ways to produce Biopol in transgenic plants Despite its current cost of production and impracticality, further developments such as those being made by Metabolix prove that alternative biopolmers such as Biopol may become used as extensively as current petroleum-based polymers.

Medicoat, Elastin and Cyclodextrin

Another biopolymer Medicoat is a slippery product used to coat catheters so that bacteria cannot get a hold and reproduce to cause infection.

The polymer Elastin is being developed at the University of New South Wales as an artificial human skin which has the potential to replace skins for burns patients.

Cyclodextrin is a toroid (hydrophilic outside and hydrophobic inside) biopolmer formed from latex alpha - amalase. It has pharmaceutical applications in medicine absorption, fragrances, food products and environmental protection.

**R. Shaw