1. Liquefied Wood as Inexpensive Precursor-Feedstock for Bio-Mediated Incorporation of (R)-3-Hydroxyvalerate into Polyhydroxyalkanoates.
- Author
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Koller, Martin, de Sousa Dias, Miguel Miranda, Rodríguez-Contreras, Alejandra, Kunaver, Matjaž, Žagar, Ema, Kržan, Andrej, and Braunegg, Gerhart
- Subjects
BIODEGRADABLE plastics ,POLYHYDROXYALKANOATES ,PROTEOBACTERIA ,CHEMICAL synthesis ,BIOPOLYMERS ,POLYESTERS - Abstract
Liquefied wood (LW) prepared in a microwave process was applied as a novel; inexpensive precursor feedstock for incorporation of (R)-3-hydroxyvalerate (3HV) into polyhydroxyalkanoate (PHA) biopolyesters in order to improve the biopolyester's material quality; Cupriavidus necator was applied as microbial production strain. For proof of concept, pre-experiments were carried out on a shake flask scale using different mixtures of glucose and LW as carbon source. The results indicate that LW definitely acts as a 3HV precursor, but, at the same time, displays toxic effects on C. necator at concentrations exceeding 10 g/L. Based on these findings, PHA biosynthesis under controlled conditions was performed using a fed-batch feeding regime on a bioreactor scale. As major outcome, a poly(3HB-co-0.8%-3HV) copolyester was obtained displaying a desired high molar mass of Mw = 5.39 × 10
5 g/mol at low molar-mass dispersity (ĐM of 1.53), a degree of crystallinity(Xc ) of 62.1%, and melting temperature Tm (176.3 °C) slightly lower than values reported for poly([R]-3-hydroxybutyrate) (PHB) homopolyester produced by C. necator; thus, the produced biopolyester is expected to be more suitable for polymer processing purposes. [ABSTRACT FROM AUTHOR]- Published
- 2015
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