Fed-Batch Synthesis of Poly(3-Hydroxybutyrate) and Poly(3-Hydroxybutyrate-co-4-Hydroxybutyrate) from Sucrose and 4-Hydroxybutyrate Precursors by Burkholderia sacchari Strain DSM 17165 (original) (raw)
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Applied Microbiology and Biotechnology, 2011
Burkholderia sp. synthase has been shown to polymerize 3-hydroxybutyrate (3HB), 3-hydroxyvalerate, and 3-hydroxy-4-pentenoic acid monomers. This study was carried out to evaluate the ability of Burkholderia sp. USM (JCM 15050) and its transformant harboring the polyhydroxyalkanoate (PHA) synthase gene of Aeromonas caviae to incorporate the newly reported 3-hydroxy-4-methylvalerate (3H4MV) monomer. Various culture parameters such as concentrations of nutrient rich medium, fructose and 4-methylvaleric acid as well as harvesting time were manipulated to produce P(3HB-co-3H4MV) with different 3H4MV compositions. The structural properties of PHA containing 3H4MV monomer were investigated by using nuclear magnetic resonance and Fourier transform infrared spectroscopy (FTIR). The relative intensities of the bands at 1,183 and 1,228 cm −1 in the FTIR spectra enabled the rapid detection and differentiation of P(3HB-co-3H4MV) from other types of PHA. In addition, the presence of 3H4MV units in the copolymer was found to considerably lower the melting temperature and enthalpy of fusion values compared with poly(3-hydroxybutyrate) (P(3HB)). The copolymer exhibited higher thermo-degradation temperature but similar molecular weight and polydispersity compared with P(3HB).
Novel precursors for production of 3-hydroxyvalerate-containing poly[( R )-hydroxyalkanoate]s
Biocatalysis and Biotransformation, 2014
Polyhydroxyalkanoates (Phas) with tailored properties are needed to meet consumer demands regarding the use of ecocompatible biobased polymeric materials and relevant plastic items. inserting 3-hydroxvalerate (3hV) monomeric units in Pha biopolyesters results in poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate] (PhbhV) copolyesters aimed at their conversion into production of biodegradable eco-friendly plastic items. as inexpensive novel precursor substrate structurally related to 3hV, a mixture of odd-numbered carboxylic acids with 9-17 carbon atoms was produced by oxidative ozonolysis of alkenes. this mixture was successfully applied for biomediated PhbhV production by Cupriavidus necator. applying this mixture as carbon substrate, a molar 3hV fraction exceeding 0.12 was obtained. the isolated copolyesters featured a low degree of crystallinity, narrow molar mass distribution, and low melting temperatures. these properties should make application of the novel 3hV-precursors interesting for large-scale production of easily processable copolyesters.
Bioengineering, 2017
Sugarcane bagasse (SCB), one of the major lignocellulosic agro-industrial waste products, was used as a substrate for biosynthesis of polyhydroxyalkanoates (PHA) by halophilic archaea. Among the various wild-type halophilic archaeal strains screened, Halogeometricum borinquense strain E3 showed better growth and PHA accumulation as compared to Haloferaxvolcanii strain BBK2, Haloarcula japonica strain BS2, and Halococcus salifodinae strain BK6. Growth kinetics and bioprocess parameters revealed the maximum PHA accumulated by strain E3 to be 50.4 ± 0.1 and 45.7 ± 0.19 (%) with specific productivity (qp) of 3.0 and 2.7 (mg/g/h) using NaCl synthetic medium supplemented with 25% and 50% SCB hydrolysate, respectively. PHAs synthesized by strain E3 were recovered in chloroform using a Soxhlet apparatus. Characterization of the polymer using crotonic acid assay, X-ray diffraction (XRD), differential scanning calorimeter (DSC), Fourier transform infrared (FT-IR), and proton nuclear magnetic resonance ( 1 H-NMR) spectroscopy analysis revealed the polymer obtained from SCB hydrolysate to be a co-polymer of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] comprising of 13.29 mol % 3HV units.
Reviews in Environmental Science and Bio/Technology, 2021
Although poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is the most promising biopolymer for petroleum-based plastics replacement, the low processes productivity as well as the high sale price represent a major barrier for its widespread usage. The present work examines comparatively the existing methods to enhance the yield of the PHBV co-polymer biologically produced and/or reduce their costs. The study is addressed to researchers working on the development of new biological production methods and/or the improvement of those currently used. At this aim, the authors have considered the analysis of some crucial aspects related to substrates and microorganism’s choice. The production strategies have been individuated, presented and discussed, either based on a single aspect (type of substrate or microorganism) or based on combined aspects (type of substrate and microorganism). Process operating conditions have been discussed as well. The analysis indicates that the addition of 3...
Poly(β-hydroxyalkanoates): Biorefinery polymers in search of applications
Die makromolekulare Chemie, 1988
Poly(6-hydroxyalkanoates) are nature's high molecular weight thermoplastic polyesters. The occur as storage granules in a variety of bacteria. From a plastics, {lm, and fibres perspective, the statistically random copolyesters based on 6-hydroxybutyrate (HB) and 6-hydroxyvalerate (HV) repeating units have high potential for commercial exploitation because of their biodegradability. They provide a range of melting points from 180°C down to 80°C and all compositions exhibit high crystallinity due t o isodimorphism. The latter i s due t o t h e similar crystalline c o n f o r m a t i o n s o f p o l y (6hydroxybut rate) (PHB) and poly(6-hydroxyvalerate) (PHV). The nascent ranules o)l a 21 mole % HV copolyester sample in freeze-dried Zacterial cells were examined b 13C solid-state NMR. A disorder in the HV ethyl side group was noteJbut backbone carbons for HB and HV units showed evidence of crystalline order which was confirmed by xray diffraction. In keeping with the isodimorphous properties of this system, electron diffraction o f cop01 ester single crystals for compositions up t o 21 mole % HV conirmed a lattice expansion previously observed for bulk crystallized P(HB-co-HV). Solution or melt crystallized films showed decreasing rates of crystallization with increasing HV content. Homogeneous blends of PHB with P(HB-co-HV) could be formed which showed a single melting peak by differential scannin calorimetry. The potential of P(HB-co-HV) as a source of value-a3ded small molecules is discussed. Depending on the method of degradation (ie., chemical or pyrolytic) chiral synthons or vinylic small molecules are obtainable in nearly quantitative yields. Because their physical properties resemble those of polyolefins this family of chiral thermoplastics will probably find wide use in biomedical applications where compatibility and absorbability are essential features.