Microstructure of copolymers of polyhydroxyalkanoates produced by glycogen accumulating organisms with acetate as the sole carbon source

Dai, Yu, Lambert, Lynette, Yuan, Zhiguo and Keller, Jurg (2008) Microstructure of copolymers of polyhydroxyalkanoates produced by glycogen accumulating organisms with acetate as the sole carbon source. Process Biochemistry, 43 9: 968-977. doi:10.1016/j.procbio.2008.04.023


Author Dai, Yu
Lambert, Lynette
Yuan, Zhiguo
Keller, Jurg
Title Microstructure of copolymers of polyhydroxyalkanoates produced by glycogen accumulating organisms with acetate as the sole carbon source
Journal name Process Biochemistry   Check publisher's open access policy
ISSN 0032-9592
1873-3298
Publication date 2008-09-01
Year available 2008
Sub-type Article (original research)
DOI 10.1016/j.procbio.2008.04.023
Open Access Status DOI
Volume 43
Issue 9
Start page 968
End page 977
Total pages 10
Editor A. J. Sinskey
J. J. Zhong
J. Boudrant
Place of publication Watford, U.K.
Publisher Elsevier
Language eng
Subject C1
969999 Environment not elsewhere classified
060504 Microbial Ecology
0601 Biochemistry and Cell Biology
Abstract The so-called glycogen accumulating organisms (GAOs), found in mixed culture anaerobic-aerobic wastewater treatment processes, are used to produce polyhydroxyalkanoates (PHAs) copolymers from a single, simple carbon source-acetate. These polymers consist of 3-hydroxybutyrate (HB), 3-hydroxyvalerate (HV), 3-hydroxy-2-methylvalerate (HmV) and 3-hydroxy-2-methylbutyrate (HmB) with a non-HB fraction of up to 37%. A detailed characterisation using H-1 and C-13 nuclear magnetic resonance (NMR) spectroscopy demonstrates that these products are true copolymers if produced under anaerobic conditions. The HmV and HmB monomers are identified and their incorporation in the polymer verified via two-dimensional (2D) NMR spectroscopy. The monomer sequence distribution analysis using a known polymer characterisation model suggests that these polyesters are mixtures of random copolymers and thus likely possess desirable properties for practical use. This assessment is supported by the polymers' physical characteristics. It was further revealed from the study that the inclusion of aerobic periods into the process could improve the overall polymer yields but resulted in production of HB monomers only, likely in the form of separate homopolymer blocks. The study for the first time investigated the microstructure of GAO-produced biopolymers; and shows that GAOs have a potential for producing high-quality polymers from a simple carbon source. (C) 2008 Elsevier Ltd. All rights reserved.
Formatted abstract
The so-called glycogen accumulating organisms (GAOs), found in mixed culture anaerobic–aerobic wastewater treatment processes, are used to produce polyhydroxyalkanoates (PHAs) copolymers from a single, simple carbon source—acetate. These polymers consist of 3-hydroxybutyrate (HB), 3-hydroxyvalerate (HV), 3-hydroxy-2-methylvalerate (HmV) and 3-hydroxy-2-methylbutyrate (HmB) with a non-HB fraction of up to 37%. A detailed characterisation using 1H and 13C nuclear magnetic resonance (NMR) spectroscopy demonstrates that these products are true copolymers if produced under anaerobic conditions. The HmV and HmB monomers are identified and their incorporation in the polymer verified via two-dimensional (2D) NMR spectroscopy. The monomer sequence distribution analysis using a known polymer characterisation model suggests that these polyesters are mixtures of random copolymers and thus likely possess desirable properties for practical use. This assessment is supported by the polymers’ physical characteristics. It was further revealed from the study that the inclusion of aerobic periods into the process could improve the overall polymer yields but resulted in production of HB monomers only, likely in the form of separate homopolymer blocks. The study for the first time investigated the microstructure of GAO-produced biopolymers and shows that GAOs have a potential for producing high-quality polymers from a simple carbon source.
Copyright © 2008 Elsevier Ltd All rights reserved.

Keyword Copolymer
Glycogen accumulating organisms (GAOs)
Mixed culture
Microstructure
NMR
Polyhydroxyalkanoates (PHAs)
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2009 Higher Education Research Data Collection
Advanced Water Management Centre Publications
 
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Created: Wed, 15 Apr 2009, 23:53:53 EST by Suzanne Read on behalf of Advanced Water Management Centre