Biosynthesis of High Quality Polyhydroxyalkanoate Co- and Terpolyesters for Potential Medical Application by the Archaeon Haloferax mediterranei |
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Authors: | Martin Koller Paula Hesse Rodolfo Bona Christoph Kutschera Aid Atlić Gerhart Braunegg |
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Affiliation: | Graz University of Technology, Institute of Biotechnology and Bioprocess Engineering, Petersgasse 12, 8010 Graz, Austria |
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Abstract: | Summary : Haloferax mediterranei was investigated for the production of two different high-performance polyhydroxyalkanoates (PHAs). A copolyester containing 6 mol-% 3-hydroxyvalerate (3HV) was produced from whey sugars as sole carbon source. The maximum specific growth rate (µmax.) and the maximum specific PHA production rate (qp max.) were determined with 0.10 1/h and 0.15 1/h, respectively. The cells contained 72.8 wt.-% of P-(3HB-co-6%-3HV) which featured low melting points between 150 and 160 °C and narrow molecular mass distribution (polydispersity PDI = 1.5). Further, a PHA terpolyester with an increased 3HV fraction as well as 4-hydroxybutyrate (4HB) building blocks was accumulated by feeding of whey sugars plus 3HV - and 4HB precursors. Kinetic analysis of the process reveals a µmax. of 0.14 1/h and a qp max. of 0.23 1/h, respectively. The final percentage of P-(3HB-co-21.8%-3HV-co-5.1%-4HB) in biomass amounted to 87.5 wt.-%. Also this material showed a narrow molecular mass distribution (PDI = 1.5) and a high difference between the two melting endotherms of the material (between 140 and 150 °C) and the onset of decomposition at 236 °C. The accomplished work provides viable strategies to obtain different high-quality PHAs which might be potential candidates for application in the medical and pharmaceutical field. |
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Keywords: | biocompatibility biopolymers Haloferax mediterranei high-performance polymers polyhydroxyalkanoates |
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