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References 67

3.9
Conclusions and Outlook

Interdisciplinary knowledge is required for further research on the production
and application of PHAs. There need to be combined efforts by microbiologists,
geneticists, botanists, chemists, polymer scientists, chemical engineers, biotech-
nologists, and medical scientists. Government agencies and venture capitalists
have strongly promoted the PHAs field to become an industrial value chain rang-
ing from agriculture, fermentation, plastics, packaging, biofuels, fine chemicals,
and medicine to nutrition. The availability of large amounts of PHAs currently
means that more polymer-specialized companies will get involved, which will lead
to more applications of PHAs and as such we will see the formation of such a value
chain accelerate more quickly.
A range of proteins and other molecules have now been successfully immobi-
lized at the surface of PHAs granules; this indicates that these bacterial storage
compounds have potential to be developed into powerful tools for diagnostic and
therapeutic biomedical applications. One strong advantage of PHA granules as
functionalized nano-/micro-beads, apart from simple and cost-effective produc-
tion, is the oriented immobilization of, for example, proteins via the GAP-tag and
thus high binding capacity of the resulting beads. Improved strategies for size con-
trol of in vivo produced beads as well as improved methods for pyrogen removal
are needed next.

Acknowledgments

The author thanks past and present members of his research group at the Institute
of Fundamental Sciences for contributions to the group’s work on biopolyester
synthesis. Work on the polyester synthases in the laboratory has been supported
mainly by grants from the Deutsche Forschungsgemeinschaft, the MacDiarmid
Institute for Advanced Materials and Nanotechnology, Massey University, and
PolyBatics Ltd. The author is also grateful to Professor Stoyko Fakirov for assisting
with writing this book chapter.

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