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1.
Matsusaki H Abe H Taguchi K Fukui T Doi Y 《Applied microbiology and biotechnology》2000,53(4):401-409
Pseudomonas sp. 61-3 accumulated a blend of poly(3-hydroxybutyrate) [P(3HB)] homopolymer and a random copolymer consisting of 3-hydroxyalkanoate
(3HA) units of 4–12 carbon atoms. The genes encoding β-ketothiolase (PhbARe) and NADPH-dependent acetoacetyl-CoA reductase (PhbBRe) from Ralstoniaeutropha were expressed under the control of promoters for Pseudomonas sp. 61-3 pha locus or R. eutropha phb operon together with phaC1
Ps gene (PHA synthase 1 gene) from Pseudomonas sp. 61-3 in PHA-negative mutants P. putida GPp104 and R. eutropha PHB−4 to produce copolyesters [P(3HB-co-3HA)] consisting of 3HB and medium-chain-length 3HA units of 6–12 carbon atoms. The introduction of the three genes into
GPp104 strain conferred the ability to synthesize P(3HB-co-3HA) with relatively high 3HB compositions (up to 49 mol%) from gluconate and alkanoates, although 3HB units were not incorporated
at all or at a very low fraction (3 mol%) into copolyesters by the strain carrying phaC1
Ps gene only. In addition, recombinant strains of R. eutropha PHB−4 produced P(3HB-co-3HA) with higher 3HB fractions from alkanoates and plant oils than those from recombinant GPp104 strains. One of the recombinant
strains, R. eutropha PHB−4/pJKSc46-pha, in which all the genes introduced were expressed under the control of the native promoter for Pseudomonas sp. 61-3 pha locus, accumulated P(3HB-co-3HA) copolyester with a very high 3HB fraction (85 mol%) from palm oil. The nuclear magnetic resonance analyses showed that
the copolyesters obtained here were random copolymers of 3HB and 3HA units.
Received: 12 July 1999 / Received revision: 1 October 1999 / Accepted: 2 October 1999 相似文献
2.
3.
Fumi Shozui Ken’ichiro Matsumoto Takahiro Sasaki Seiichi Taguchi 《Applied microbiology and biotechnology》2009,84(6):1117-1124
Class II polyhydroxyalkanoate synthase from Pseudomonas sp. 61-3 (PhaC1Ps) synthesizes 3-hydroxybutyrate (3HB)-based copolyesters, P[3HB-co-3-hydroxyalkanoate (3HA)]. Four sites (130, 325, 477, and 481) in PhaC1Ps that affect the cellular content and 3HB fraction of P(3HB-co-3HA) produced have been identified. Simple combination of beneficial mutations at the sites successfully increased 3HB fraction
in the copolymers (62 mol.%). However, polymer content was often largely decreased (0.2 wt.%) regardless of an enhancement
in 3HB fraction, compared to the wild-type enzyme (14 mol.% 3HB and 12 wt.%; Matsumoto et al. (2006) Biomacromolecules, 7:2436–2442).
In the present study, we attempted to explore residues combination at the four sites to overcome the problem. Here, pairwise
saturation mutagenesis at the neighboring sites 477 and 481 of PhaC1Ps was performed using single and double mutations at sites 130 and 325 as templates to increase 3HB fraction in the copolymer
without reducing the polymer content in recombinant Escherichia coli. These useful PhaC1Ps mutants were screened based on enhanced P(3HB) content and were subsequently applied to P(3HB-co-3HA) production. Among the mutants tested, the Ser325Cys/Ser477Lys/Gln481Leu mutant exhibited increased 3HB fraction in copolymer
(63 mol.%) and also polymer content (18 wt.%), indicating that mutation scrambling was effective for obtaining the desired
mutants. 相似文献
4.
Summary Random copolymers of 3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB) with a wide range of compositions varying from 0 to 83 mol% 4HB were produced by Alcaligenes latus from the mixed carbon substrates of 3-hydroxybutyric and 4-hydroxybutyric acids. The structure and physical properties of P(3HB-co-4HB) were characterized by1H and13C NMR spectroscopy, gel-permeation chromatography, and differential scanning calorimetry. The isothermal radial growth rates of spherulites of P(3HB-co-4HB) were much slower than the rate of P(3HB) homopolymer. The enzymatic degradation rates of P(3HB-co-4HB) films by a PHB depolymerase were strongly influenced by the copolymer composition. 相似文献
5.
《Bioscience, biotechnology, and biochemistry》2013,77(8):1710-1712
A newly isolated mutation (Gln508Leu) and a combination of it with previously discovered beneficial mutations in polyhydroxyalkanoate synthase 1 from Pseudomonas sp. 61-3 were found to enhance the production of poly(3-hydroxybutyrate) [P(3HB)] and poly(3HB-co-3-hydroxyalkanoate)s in recombinant Escherichia coli. 相似文献
6.
S. Vigneswari S. Vijaya M. I. A. Majid K. Sudesh C. S. Sipaut M. N. M. Azizan A. A. Amirul 《Journal of industrial microbiology & biotechnology》2009,36(4):547-556
Cupriavidus sp. USMAA1020, a local isolate was able to biosynthesis poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] copolymer with various 4HB precursors as the sole carbon source. Manipulation of the culture conditions such as cell
concentration, phosphate ratio and culture aeration significantly affected the synthesis of P(3HB-co-4HB) copolymer and 4HB composition. P(3HB-co-4HB) copolymer with 4HB compositions ranging from 23 to 75 mol% 4HB with various mechanical and thermal properties were successfully
produced by varying the medium aeration. The physical and mechanical properties of P(3HB-co-4HB) copolymers were characterized by NMR spectroscopy, gel-permeation chromatography, tensile test, and differential scanning
calorimetry. The number-average molecular weights (M
n) of copolymers ranged from 260 × 103 to 590 × 103Da, and the polydispersities (M
w/M
n) were between 1.8 and 3.0. Increases in the 4HB composition lowered the molecular weight of these copolymers. In addition,
the increase in 4HB composition affected the randomness of copolymer, melting temperature (T
m), glass transition temperature (T
g), tensile strength, and elongation to break. Enzymatic degradation of P(3HB-co-4HB) films with an extracellular depolymerase from Ochrobactrum sp. DP5 showed that the degradation rate increased proportionally with time as the 4HB fraction increased from 17 to 50 mol%
but were much lower with higher 4HB fraction. Degradation of P(3HB-co-4HB) films with lipase from Chromobacterium viscosum exhibited highest degradation rate at 75 mol% 4HB. The biocompatibility of P(3HB-co-4HB) copolymers were evaluated and these copolymers have been shown to support the growth and proliferation of fibroblast
cells. 相似文献
7.
Faezah A. Nor Rahayu A. Vigneswari S. Majid M. I. A. Amirul A. A. 《World journal of microbiology & biotechnology》2011,27(10):2455-2459
The regulation of 4-hydroxybutyrate (4HB) molar fraction in the poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] of a local isolate Cupriavidus sp. USMAA1020 was attempted by employing a feeding strategy through fed-batch fermentation in 100-L fermenter. The growth
of Cupriavidus sp. USMAA1020 was enhanced by frequently feeding carbon and nitrogen at a ratio of 5 (C/N 5) using a DO-stat with cascade
mode at 20% (v/v) dissolved oxygen (DO). The feeding of C/N 5 and the use of the DO-stat mode were able to regulate the 4HB
composition from 0–67 mol% by sequential feeding of γ-butyrolactone and supplementing oleic acid. A high 4HB molar fraction
of 67 mol% with a PHA concentration of 5.2 g/L was successfully obtained by employing this feeding strategy. Notably, enzymatic
degradation carried out enhanced the 4HB composition of the copolymer synthesized. PHB depolymerase enzyme from Acidovorax sp. was used to degrade this P(3HB-co-70-mol%4HB) copolymer and the 4HB composition could be increased up to 83 mol%. The degradation process was observed by monitoring
the time-dependent change in the weight loss of copolymer films. The percentage of weight loss of solvent-cast film increased
proportionally up to 19% within 3 h, whereas salt-leached films showed 90% of weight loss within 3 h of incubation and were
completely degraded by 4 h. The molecular weight (M
n
) of the films treated with enzyme demonstrated a slight decrease. SEM observation exhibited a rough surface morphology of
the copolymer degraded with depolymerase enzyme. 相似文献
8.
Cloning and Molecular Analysis of the Poly(3-hydroxybutyrate) and Poly(3-hydroxybutyrate-co-3-hydroxyalkanoate) Biosynthesis Genes in Pseudomonas sp. Strain 61-3 总被引:1,自引:0,他引:1
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Hiromi Matsusaki Sumihide Manji Kazunori Taguchi Mikiya Kato Toshiaki Fukui Yoshiharu Doi 《Journal of bacteriology》1998,180(24):6459-6467
9.
Synthesis of biodegradable polyesters by Gram negative bacterium isolated from Malaysian environment
Al Ashraf Amirul S. N. Syairah Ahmad R. M. Yahya M. N. M. Azizan M. I. A. Majid 《World journal of microbiology & biotechnology》2008,24(8):1327-1332
A locally isolated Gram negative bacterium, Cupriavidus sp. USMAA9-39 was able to produce various types of biodegradable polyesters through a two-step cultivation process. These
are copolymer poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)], copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] and terpolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxybutyrate) [P(3HB-co-3HV-co-4HB)]. These polymers were synthesized by this bacterium when grown with a combination of some carbon sources. The biosynthesis
of P(3HB-co-4HB) was achieved by using carbon sources such as γ-butyrolactone or 1,4-butanediol or by a combination of oleic acid with
either γ-butyrolactone or 1,4-butanediol. Meanwhile, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) was produced using 1-pentanol or valeric acid or by a combination of oleic acid with either 1-pentanol
or valeric acid. When γ-butyrolactone or 1,4-butanediol with either valeric acid or 1-pentanol were used as mixed carbon sources,
P(3HB-co-3HV-co-4HB) terpolymer were produced. The presence of 3HB, 3HV or/and 4HB monomers were confirmed by gas chromatography and nuclear
magnetic resonance (NMR) spectroscopy. 相似文献
10.
A polyhydroxyalkanoate (PHA) synthase gene phaC2
Ps from Pseudomonas stutzeri strain 1317 was introduced into a PHA synthase gene phbC
Re negative mutant, Ralstonia eutropha PHB−4. It conferred on the host strain the ability to synthesize PHA, the monomer compositions of which varied widely when grown
on different carbon sources. During cultivation on gluconate, the presence of phaC2
Ps in R. eutropha PHB−4 led to the accumulation of polyhydroxybutyrate (PHB) homopolymer in an amount of 40.9 wt% in dry cells. With fatty acids,
the recombinant successfully produced PHA copolyesters containing both short-chain-length and medium-chain-length 3-hydroxyalkanoate
(3HA) of 4–12 carbon atoms in length. When cultivated on a mixture of gluconate and fatty acid, the monomer composition of
accumulated PHA was greatly affected and the monomer content was easily regulated by the addition of fatty acids in the cultivation
medium. After the (R)-3-hydroxydecanol-ACP:CoA transacylase gene phaG
Pp from Pseudomonas putida was introduced into phaC2
Ps-containing R. eutropha PHB−4, poly(3HB-co-3HA) copolyester with a very high 3-hydroxybutyrate (3HB) fraction (97.3 mol%) was produced from gluconate and the monomer
compositions of PHA synthesized from fatty acids were also altered. This study clearly demonstrated that PhaC2Ps cloned from P. stutzeri 1317 has extraordinarily low substrate specificity in vivo, though it has only 54% identity in comparison to a previously described low-substrate-specificity PHA synthase PhaC1Ps from Pseudomonas sp. 61–3. This study also indicated that the monomer composition and content of the synthesized PHA can be effectively modulated
by controlling the addition of carbon sources or by modifying metabolic pathways in the hosts. 相似文献
11.
Ralstonia eutropha NCIMB 11599 and ATCC 17699 were grown, and their productions of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] compared. In flask cultures ofR. eutropha NCIMB 11599, cell concentration, P(3HB-co-4HB) concentration and polymer content decreased considerably with increases in the γ-butyrolactone concentration, and the
4HB fraction was also very low (maximum 1.74 mol%). In fed-batch cultures ofR. eutropha NCIMB 11599, glucose and γ-butyrolactone were fed as the carbon sources, under a phosphate limitation strategy. When glucose
was fed as the sole carbon source, with its concentration controlled using an on-line glucose analyzer, 86% of the P(3HB)
homopolymer was obtained from 201 g/L of cells. In a two-stage fed-batch culture, where the cell concentration was increased
to 104 g/L, with glucose fed in the first step and constant feeding of γ-butyrolactone, at 6 g/h, in the second, final cell
concentration at 67 h was 106 g/L, with a polymer content of 82%, while the 4HB fraction was only 0.7 mol%. When the same
feeding strategy was applied to the fedbatch culture ofR. eutropha ATCC 17699, where the cell concentration was increased to 42 g/L, by feeding fructose in the first step and γ-butyrolactone
(1.5 g/h) in the second, the final cell concentration, polymer content and 4HB fraction at 74 h were 51 g/L, 35% and 32 mol%,
respectively. In summary,R. eutropha ATCC 17699 was better thanR. eutropha NCIMB 11599 in terms of P(3HB-co-4HB) production with various 4HB fractions. 相似文献
12.
Production of copolymer consisting of 3-hydroxybutyrate and 3-hydroxyvalerate by fed-batch culture of Alcaligenes SP. SH-69 总被引:2,自引:0,他引:2
Summary Production of copolymer consisting of 3-hydroxybutyrate and 3-hydroxyvalerate [poly(3HB-co-3HV)] by fed-batch culture of Alcaligenes sp. SH-69 was investigated using glucose as a sole carbon source. Synthesis of poly(3HB-co-3HV) during the polymer accumulation stage was favored under dissolved oxygen tension at 20% and C/N ratio (mol glucose/mol ammonium) of 23.1. When conditions were optimal, 36 g liter-1 of poly(3HB-co-3HV) containing 3.0 mol% of 3HV was produced. Decreasing C/N ratio resulted in an increase of 3HV fraction in the copolymer to a maximum level of 6.3 mol%. 相似文献
13.
A. Rahayu Z. Zaleha Ahmad R. M. Yahya M. I. A. Majid A. A. Amirul 《World journal of microbiology & biotechnology》2008,24(11):2403-2409
A one-step cultivation process for the production of biodegradable polymer poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] by Cupriavidus sp. USMAA2-4 was carried out using various carbon sources. It was found that Cupriavidus sp. USMAA2-4 could produce approximately 44 wt.% copolymer of P(3HB-co-4HB) with 27 mol% 4HB composition when the combination of oleic acid and 1,4-butanediol are used as carbon sources in 60 h
cultivation. The manipulation of carbon-to-nitrogen ratio (C/N) resulted in the increase of dry cell weight, PHA content as
well as 4HB composition. A new strategy of introducing oleic acid and 1,4-butanediol together and separately at different
concentration demonstrated different yield in PHA content ranging from 47 to 58 wt.%. The molecular weight obtained was 234 kDa
(by adding 1,4-butanediol and oleic acid together) and 212 kDa (by adding 1,4-butanediol separately). The copolymer of P(3HB-co-4HB) produced by Cupriavidus sp. USMAA2-4 was detected statistically as a random copolymer when analysed by nuclear magnetic resonance (NMR) spectroscopy. 相似文献
14.
A. A. Amirul Ahmad R. M. Yahya K. Sudesh M. N. M. Azizan M. I. A. Majid 《World journal of microbiology & biotechnology》2009,25(7):1199-1206
Samples from various natural environments in Peninsular Malaysia were screened for microorganisms that are capable of producing
poly(3-hydroxybutyrate-co-4-hydroxybutyrate). A total of 663 isolates were isolated and 119 out of these isolates were identified as possible PHA producers
based on Nile red staining methods. All these potential producers emitted pink fluorescence when grown on solid mineral salts
medium (MSM) containing Nile red and exposed to UV light. The isolates obtained in this study were cultivated in MSM containing
γ-butyrolactone as the carbon source. Gas chromatography (GC) analysis confirmed that 95 out of the 119 isolates were PHA
producers. Among the 95 positive isolates, 77 isolates produced only P(3HB) homopolymer and 18 isolates produced PHA containing
3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB) monomers. Of these 18 isolates, USMAA1020 was screened as the best P(3HB-co-4HB) producer based on GC analysis. For further confirmation, PHA was extracted from the isolate and analyzed by GC as well
as nuclear magnetic resonance (NMR). Results from both analyses confirmed that this isolate was capable of producing PHA containing
3HB and 4HB. Based on, biochemical characterization, 16S rRNA sequencing, DNA base composition, cellular fatty acids analysis
and DNA–DNA hybridization, it is clearly indicated that this isolate belongs to the genus Cupriavidus. Poly(3HB-co-4HB) was synthesized by this bacterium in one-stage, two-stage and three-stage cultivation using γ-butyrolactone as the carbon
source. The highest 4HB composition of 82 mol% was obtained through three-stage cultivation. 相似文献
15.
Ziyu Wang Yifei Zheng Mengke Ji Xu Zhang Huan Wang Yuemeng Chen Qiong Wu Guo-Qiang Chen 《Microbial biotechnology》2022,15(5):1586-1597
Bacterial outer membrane (OM) is a self-protective and permeable barrier, while having many non-negligible negative effects in industrial biotechnology. Our previous studies revealed enhanced properties of Halomonas bluephagenesis based on positive cellular properties by OM defects. This study further expands the OM defect on membrane compactness by completely deleting two secondary acyltransferases for lipid A modification in H. bluephagenesis, LpxL and LpxM, and found more significant advantages than that of the previous lpxL mutant. Deletions on LpxL and LpxM accelerated poly(3-hydroxybutyrate) (PHB) production by H. bluephagenesis WZY229, leading to a 37% increase in PHB accumulation and 84-folds reduced endotoxin production. Enhanced membrane permeability accelerates the diffusion of γ-butyrolactone, allowing H. bluephagenesis WZY254 derived from H. bluephagenesis WZY229 to produce 82wt% poly(3-hydroxybutyrate-co-23mol%4-hydroxybutyrate) (P(3HB-co-23mol%4HB)) in shake flasks, showing increases of 102% and 307% in P(3HB-co-4HB) production and 4HB accumulation, respectively. The 4HB molar fraction in copolymer can be elevated to 32 mol% in the presence of more γ-butyrolactone. In a 7-l bioreactor fed-batch fermentation, H. bluephagenesis WZY254 supported a 84 g l−1 dry cell mass with 81wt% P(3HB-co-26mol%4HB), increasing 136% in 4HB molar fraction. This study further demonstrated that OM defects generate a hyperproduction strain for high 4HB containing copolymers. 相似文献
16.
T. M. Fahima Azira A. A. Nursolehah Y. Norhayati M. I. A. Majid A. A. Amirul 《World journal of microbiology & biotechnology》2011,27(10):2287-2295
A locally isolated Gram-negative bacterium, Cupriavidus sp. USMAA2-4 was found capable of producing terpolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxybutyrate) [P(3HB-co-3HV-co-4HB)] using γ-butyrolactone or 1,4-butanediol with either valeric acid or 1-pentanol as the carbon source. The present of
3HB, 3HV and 4HB monomers were confirmed by gas chromatography (GC) and nuclear magnetic resonance (NMR) analysis. PHA concentration
of 1.9 g/l was the highest value obtained using the combination of 1,4-butanediol and 1-pentanol through one-step cultivation
process. PHA concentration obtained through two-step cultivation process was higher for all the combinations and the highest
value achieved was 2.5 g/l using γ-butyrolactone and 1-pentanol as carbon source. Various molar fractions of 4HB and 3HV ranging
from 6 to 14 mol% and 39 to 87 mol%, respectively were produced through two-step cultivation process by manipulating the concentration
of γ-butyrolactone. As the culture aeration was reduced, the molar fraction of 3HV and 4HB increased from 40 to 67 mol% and
10 to 24 mol%, respectively while the dry cell weight and PHA content decreased. The terpolymer produced was characterized
using gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). The number-average molecular weight
(M
n) and the melting temperature (T
m)) of the terpolymer were in the range of 177–484 kDa and 160–164°C, respectively. 相似文献
17.
Polyhydroxyalkanoate (PHA) synthesis genes phaPCJ
Ac
cloned from Aeromonas caviae were transformed into Pseudomonas putida KTOY06ΔC, a mutant of P. putida KT2442, resulting in the ability of the recombinant P. putida KTOY06ΔC (phaPCJ
A.c
) to produce a short-chain-length and medium-chain-length PHA block copolymer consisting of poly-3-hydroxybutyrate (PHB) as
one block and random copolymer of 3-hydroxyvalerate (3HV) and 3-hydroxyheptanoate (3HHp) as another block. The novel block
polymer was studied by differential scanning calorimetry (DSC), nuclear magnetic resonance, and rheology measurements. DSC
studies showed the polymer to possess two glass transition temperatures (T
g), one melting temperature (T
m) and one cool crystallization temperature (T
c). Rheology studies clearly indicated a polymer chain re-arrangement in the copolymer; these studies confirmed the polymer
to be a block copolymer, with over 70 mol% homopolymer (PHB) of 3-hydroxybutyrate (3HB) as one block and around 30 mol% random
copolymers of 3HV and 3HHp as the second block. The block copolymer was shown to have the highest tensile strength and Young’s
modulus compared with a random copolymer with similar ratio and a blend of homopolymers PHB and PHVHHp with similar ratio.
Compared with other commercially available PHA including PHB, PHBV, PHBHHx, and P3HB4HB, the short-chain- and medium-chain-length
block copolymer PHB-b-PHVHHp showed differences in terms of mechanical properties and should draw more attentions from the PHA research community. 相似文献
18.
《Process Biochemistry》2007,42(9):1342-1347
Recombinant Aeromonas hydrophila 4AK4 harboring phbA and phbB (phaAB) genes encoding β-ketothiolase and acetoacetyl-CoA reductase of Ralstonia eutropha produced a terpolyester of 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), and 3-hydroxyhexanoate (3HHx) [P(3HB-co-3HV-co-3HHx)] from mixtures of dodecanoic acid and propionic acid. Depending on the concentration of propionic acid in bacterial cultures, cell growth represented by cellular dry weight (CDW), P(3HB-co-3HV-co-3HHx) contents in dry cells and 3HV molar percentage in the terpolyester ranged from 0.43 g l−1 to 3.29 g l−1, 20.7% to 35.6%, 2.3 mol% to 7.1 mol%, respectively. Number average molecular (Mn) weights of the terpolyesters were 303,000–800,000, independent from monomer fraction content. This terpolyester was characterized by nuclear magnetic resonance (NMR), gel-permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and stress–strain measurement studies. Results showed that the terpolyester had higher thermal stability and elongation at break compared with that of homopolymer poly(3-hydroxybutyrate) (PHB) and its copolymers P(3HB-co-5 mol%3HV) or P(3HB-co-12 mol%3HHx). In addition, the terpolyester had lower melting (Tm) temperatures and enthalpy of fusions (ΔHm) than PHB did. 相似文献
19.
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). 相似文献
20.
Summary The synthesis of poly(3-hydroxyalkanoates) [P(3HA)] by a new Alcaligenes species was investigated. The new species was grown on various carbon sources such as n-alkanoic acids of carbon numbers ranging from C2 to C22, plant oils and animal fats, and accumulated P(3HA) within the cells. When the bacterium was cultured in mineral media containing sodium salts of n-alkanoic acids, the homopolymer of poly(3-hydroxybutyrate) [P(3HB)] was produced from n-alkanoates of even carbon numbers, whereas the copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate units [P(3HB-co-3HV)] was produced from n-alkanoates of odd carbon numbers. Relatively high yields of both dry cells and P(3HA) were obtained by the use of n-alkanoates from C12 to C16 as the sole carbon source.
Correspondence to: Y. Doi 相似文献