The Various Types of Polyhydroxyalkanoates

PHA can be divided into two main groups based on the number of constituent carbon atoms in their monomer units, these being the short-chain-length (SCL) PHA that contain monomer units with 3-5 carbon atoms, and the medium-chain-length (MCL) PHA that contain monomer units of 6-14 carbon atoms [2]. 

The most common PHAscl are P(3HB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) P(3HB-co-3HV). These materials have mechanical properties that 

PHAmcl are flexible, have low crystallinity, tensile strength and melting point. There have been reports of several bacteria that are able to synthesise PHA containing both SCL- and MCL-monomers [14]. 

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