abstract
Microbially produced polyhydroxyalkanoates (PHAs) are fully biodegradable biopolyesters
that have attracted much attention recently as alternative polymeric materials that can be
produced from biorenewable and biowaste resources. The properties of these biological
polymers are affected by the same fundamental principles as those of fossil-fuel derived
polyolefins, with a broad range of compositions available based on the incorporation of
different monomers into the PHA polymer structure, and with this broad range tailoring
subsequent properties. This review comprehensively covers current understanding with
respect to PHA biosynthesis and crystallinity, and the effect of composition, microstructure
and supramacromolecular structures onchemomechanical properties.Whilepolymer composition
and microstructure are shown to affect these properties, the review also finds that
a key driver for determining polymer performance properties is compositional distribution.
From this review it follows that PHA–PHA blend compositions are industrially important,
and the performance properties of such blends are discussed. A particular need is identified
for further research into the effect of chemical compositional distribution on macromolecular
structure and end-use properties, advanced modeling ofthe PHA accumulation process
and chain growth kinetics for better process control.