Crystallisation and fractionation of selected polyhydroxyalkanoates produced from mixed cultures

Laycock, Bronwyn, Arcos-Hernandez, Monica V., Langford, Alexandra, Pratt, Steven, Werker, Alan, Halley, Peter J. and Lant, Paul A. (2014) Crystallisation and fractionation of selected polyhydroxyalkanoates produced from mixed cultures. New Biotechnology, 31 4: 345-356. doi:10.1016/j.nbt.2013.05.005

Author Laycock, Bronwyn
Arcos-Hernandez, Monica V.
Langford, Alexandra
Pratt, Steven
Werker, Alan
Halley, Peter J.
Lant, Paul A.
Title Crystallisation and fractionation of selected polyhydroxyalkanoates produced from mixed cultures
Journal name New Biotechnology   Check publisher's open access policy
ISSN 1871-6784
Publication date 2014-06-25
Year available 2013
Sub-type Article (original research)
DOI 10.1016/j.nbt.2013.05.005
Open Access Status
Volume 31
Issue 4
Start page 345
End page 356
Total pages 12
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Collection year 2014
Language eng
Formatted abstract
• PHA biopolymers from mixed microbial cultures contain a broad mix of copolymers.
• Differential scanning calorimetry studies demonstrated the presence of blends.
• Solvent fractionation studies confirmed this by isolating subfractions.
• The crystallisation rate of higher melting fractions is faster than for lower melting.
• Mechanical properties will be controlled by crystallisation kinetics and morphology.

Poly[R-3-hydroxybutyrate-co-(R-3-hydroxyvalerate)] (PHBV) copolymers were produced from mixed cultures of biomass (activated sludge) fed with acetic acid (HAc) and propionic acid (HPr). Feeding was performed in such a way as to produce materials with a wide range of monomer compositions and microstructures. Solvent-cast thin films of these materials have recently been shown to exhibit a narrow range of mechanical properties similar to those of the homopolymer poly(R-3-hydroxybutyrate) (PHB) [1]. In this work, more detailed analyses of the thermal and crystallisation properties of these mixed-culture polyesters have revealed that they like comprise complex blends with broad compositional distribution of random and/or blocky copolymers of very different 3-hydroxyvalerate (3HV) contents and melting temperatures and thus have very different respective crystallisation kinetics. This blend complexity was confirmed by solvent fractionation of selected samples. The findings support the hypothesis that overall mechanical properties of these complex copolymer blend materials will be strongly influenced by the more rapidly crystallising components that form the matrix within which the slower crystallising components exist as microdomains. New opportunities in the material development of PHAs are likely to be found in establishing and exploiting such structure–function relationships.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Published online ahead of print 21 May 2013.

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Chemical Engineering Publications
Official 2014 Collection
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Citation counts: TR Web of Science Citation Count  Cited 5 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 7 times in Scopus Article | Citations
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Created: Sun, 15 Sep 2013, 17:54:16 EST by Dr Bronwyn Laycock on behalf of School of Chemical Engineering