Burkholderia cepacia copolymer

Keenan, T.M., Tanenbaum, S.W., Stipanovic, A.J. and Nakas, J.P. 2004. Production and Characterization of Poly-p-IIydroxyalkanoate Copolymers from Burkholderia Cepacia Utilizing Xylose and Levulinic acid. Biotechnol. Progr., 20, 1697-1704. 

Table 1. Physical characteristics of P(3HB-cii-3HV) copolymers produced by Burkholderia cepacia from detoxified NREL CF/aspen-based hemicellulosic hydrolysate and levulinic acid.

Table II. Thermal characteristics of P(3HB-C0-3HV) copolymers produced by shake-flask cultures of Burkholderia cepacia from 2.2 % (w/v) xylose and 0.07-0.57 % (w/v) levulinic acid.

Kamm B, Kamm M (2004) Principles of biorefineries. Appl Microbiol Biotechnol 64 137-145 Keenan T, Tanenbaum S, Stipanovic A, Nakas J (2004) Production and characterization of poly-beta-hydroxyalkanoate copolymers from Burkholderia cepacia utilizing xylose and levulinic acid. Biotechnol Prog 20(6) 1697-1704... 

Poly(3HB-co-3H4PE) was also produced by new soil isolates from unrelated carbon sources [113]. Two strains of the recently redesignated Burkholderia cepacia (formerly Pseudomonas cepacia) accumulated the copolymer from either gluconate or sucrose. In one case, a 6.9-mol%-3H4PE polymer made up 70% of the CDM. Starting from tiglic acid with or without gluconic acid as a second carbon source, B. cepacia... 

Copolyesters of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) were produced by Burkholderia cepacia D1 at 30 °C in nitrogen-free culture media containing n-butyric acid and/or n-valeric acid [115]. When n-valeric acid was used as the sole carbon source, the 3HV fraction in copolyester increased from 36 to 90 mol% as the concentration of n-valeric acid in the culture medium was increased from 1 to 20 g/1. The addition of n-butyric acid to the culture solution resulted in a decrease in the 3HV fraction in copolyester. The copolymers biosynthesized by this method were mixtures of random copolymers having a wide variety of composition of the 3HV component. The melting points of the fractionated copolymers show a concave curve with the minimum at the 3HV content of approximately 40 mol%. The alpha-parameter of lattice indices of the PHB crystal for the fractionated copolymers largely increased as the 3HV composition increased. Biodegradability of the copolymer increased with the lower content of 3HV composition and/or the lower crystallinity. 

Compositionally relevant chemical shift expansions of 300 Hz NMR spectra obtained from P(3HB-co-3HV) samples, illustrating a progressive increase in the mol% 3HV fraction of copolymers produced by Burkholderia cepacia through regulation of the ratio of levulinic acid (cosubstrate) to xylose (substrate) added to the fermentation medium. Chemical structure schematic of P(3HB-co-3HV) displays the methyl side-chain residues of the corresponding monomers, represented quantitatively by the integrated areas of the 3HB doublet (1.27 ppm) and the 3HV triplet (0.88 ppm) (Keenan eta ., 2004). 

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