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Автор(ы) : Volova T. G., Goncharov D. B., Nikolaeva E. D., Shishatskaya E. I.
Заглавие : Electrospinning of degradable phas: Process, properties, applications
Место публикации :: Nova Science Publishers, Inc., 2017. - С. 1-56
Ключевые слова (''Своб.индексиров.''): biological and physical/mechanical properties--cell proliferation--electrospinning--nonwoven membranes--pha--scaffolds--skin regeneration--ultrafine fibers--wound dressings
Аннотация: An integrated study has been performed to investigate the process of formation of ultrafine fibers and nonwoven membranes by electrospinning from natural degradable polymers-polyhydroxyalkanoates (PHAs); physical, mechanical, and biological properties of the products have been studied. Then, electrospinning was used to prepare ultrafine fibers from PHAs with different compositions: P(3HB) and its copolymers P(3HB-co-4HB), P(3HB-co-3HV), and P(3HB-co-3HHx). The main process parameters, that influence UF-fiber diameter and properties of fibrous non-woven membranes) (polymer concentration, solution feeding rate, working distance, and applied voltage), were investigated and their effects evaluated. This study was the first to compare biological and physical/mechanical parameters of PHAs with different chemical compositions as dependent upon the fractions of monomers, constituting the polymers and fiber orientation. Electrospun polymer membranes, prepared from the [P(3HB-co-4HB)], were tested as wound dressings. The developed nonwoven membranes can be used as the equivalent of collagen skine dressings in the treatment of burns of degree II. Experiments on laboratory animals with model skin defects showed, that the membranes fitted the wound shape good, protected the wound from external influences, and facilitated wound healing, promoting fast repair. The successful experiments on laboratory animals were followed by pilot clinical trials of nanomembranes, comprised of PHA membranes as wound dressings in the treatment of septic wounds. During the regeneration phase, PHA membranes served as a scaffold for the new tissue on the skin and filled out soft tissue defects. The formation of the uniform and sufficiently vascularized tissue is a prerequisite for quicker wound healing and can serve as a basis for the subsequent skin grafting and spontaneous re-epithelialization of superficial wounds. The wound dressing, tested in this clinical trial, performs important physiological functions of natural skin, provides a barrier against secondary infection, reduces fluid loss, and, at the same time, does not keep the air out. © 2017 Nova Science Publishers, Inc.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova, Tatiana G., Prudnikova, Svetlana V., Vinogradova, Olga N., Syrvacheva, Darya A., Shishatskaya, Ekaterina I.
Заглавие : Microbial Degradation of Polyhydroxyalkanoates with Different Chemical Compositions and Their Biodegradability
Колич.характеристики :15 с
Коллективы : Russian Science Foundation [14-26-00039]
Место публикации : Microb. Ecol.: SPRINGER, 2017. - Vol. 73, Is. 2. - С. 353-367. - ISSN 0095-3628, DOI 10.1007/s00248-016-0852-3. - ISSN 1432-184X(eISSN)
Примечания : Cited References:65. - This study was supported by the Russian Science Foundation (Grant No. 14-26-00039).
Предметные рубрики: TROPICAL COASTAL WATERS
PHA-DEGRADING BACTERIA
ALCALIGENES-EUTROPHUS
Ключевые слова (''Своб.индексиров.''): degradable polyhydroxyalkanoates--pha--soil--pha-degrading--microorganisms
Аннотация: The study addresses degradation of polyhydroxyalkanoates (PHA) with different chemical compositions-the polymer of 3-hydroxybutyric acid [P(3HB)] and copolymers of P(3HB) with 3-hydroxyvalerate [P(3HB/3HV)], 4-hydroxybutyrate [P(3HB/4HB)], and 3-hydroxyhexanoate [P(3HB/3HHx)] (10-12 mol%)-in the agro-transformed field soil of the temperate zone. Based on their degradation rates at 21 and 28 A degrees C, polymers can be ranked as follows: P(3HB/4HB) P(3HB/3HHx) P(3HB/3HV) P(3HB). The microbial community on the surface of the polymers differs from the microbial community of the soil with PHA specimens in the composition and percentages of species. Thirty-five isolates of bacteria of 16 genera were identified as PHA degraders by the clear zone technique, and each of the PHA had both specific and common degraders. P(3HB) was degraded by bacteria of the genera Mitsuaria, Chitinophaga, and Acidovorax, which were not among the degraders of the three other PHA types. Roseateles depolymerans, Streptomyces gardneri, and Cupriavidus sp. were specific degraders of P(3HB/4HB). Roseomonas massiliae and Delftia acidovorans degraded P(3HB/3HV), and Pseudoxanthomonas sp., Pseudomonas fluorescens, Ensifer adhaerens, and Bacillus pumilus were specific P(3HB/3HHx) degraders. All four PHA types were degraded by Streptomyces.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T., Kiselev E., Zhila N., Shishatskaya E.
Заглавие : Synthesis of Polyhydroxyalkanoates by Hydrogen-Oxidizing Bacteria in a Pilot Production Process
Место публикации : Biomacromolecules: American Chemical Society, 2019. - Article in press. - ISSN 15257797 (ISSN) , DOI 10.1021/acs.biomac.9b00295
Аннотация: The synthesis of polyhydroxyalkanoates (PHAs) was scaled up to pilot production in a 150-L fermenter on sugars (fructose and glucose) and purified and crude glycerol in a culture of the wild-type strain Cupriavidus necator B-10646. Over 60 h of cultivation, a cell concentration of 150-160 g/L was obtained on purified glycerol and glucose; cultivation on fructose and crude glycerol resulted in a cell concentration of 130 ± 10 g/L. Polymer content and yield coefficients for the biomass were similar on all substrates (80-85 wt % and 0.29-0.33 kg biomass/kg carbon substrate, respectively). Copolymers poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) and terpolymers poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxybutyrate) having a decreased degree of crystallinity (36-46%) were first synthesized in the scaled-up process using C. necator B-10646 cultivated on glycerol. These results will provide the basis for scaling-up PHA synthesis in an organotrophic C. necator B-10646 culture. © 2019 American Chemical Society.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhila, Natalia, Shishatskaya, Ekaterina
Заглавие : Properties of PHA bi-, ter-, and quarter-polymers containing 4-hydroxybutyrate monomer units
Колич.характеристики :8 с
Коллективы : Russian Science Foundation [17-15-01352]
Место публикации : Int. J. Biol. Macromol.: ELSEVIER SCIENCE BV, 2018. - Vol. 111. - С. 1019-1026. - ISSN 0141-8130, DOI 10.1016/j.ijbiomac.2018.01.130. - ISSN 1879-0003(eISSN)
Примечания : Cited References:39. - The research was supported by the Russian Science Foundation (grant No. 17-15-01352).
Предметные рубрики: ALCALIGENES-FAECALIS T1
COMAMONAS-ACIDOVORANS
ENZYMATIC DEGRADATION
Ключевые слова (''Своб.индексиров.''): polyhydroxyalkanoates--4-hydroxybutyrate monomer units--physicochemical--and mechanical properties
Аннотация: The present study investigates physicochemical, mechanical, and biological properties of polyhydroxyalkanoate (PHA) copolymers containing 4-hydroxybutyrate (4HB) synthesized in Cupriavidus eutrophus B10646 culture. In poly(3-hydroxybutyrate/4-hydroxybutyrate) [P(3HB/4HB)]bipolymers, 4HB varied between 10.4 and 75.0 mol%; in poly(3-hydroxybutyrate/3-hydroxyvalerate/4-hydroxybutyrate) terpolymers, 4HB constituted 28.7-55.6 mol%; and in poly(3-hydroxybutyrate/3-hydroxyvalerate/4-hydroxybutyrate/3-hydroxyhexanoate) quaterpolymers, 4HB varied between 9.3 and 13.3 mol%. The degree of crystallinity of P(3HB/4HB) copolymers decreased consistently with an increase in 4HB content, reaching 38%. The incorporation of 3-hydroxyvalerate and 3-hydroxyhexanoate into copolymers enhanced that effect. The effect of 4HB monomer units on temperature properties of copolymers was exhibited as lowering of the melting temperature and crystallization temperature, which improved the processing-related properties of the copolymers. All copolymers containing 4HB showed enhanced elongation at break compared to poly(3-hydroxybutyrate). Polymer films prepared from PHA5 with different chemical composition had similar microstructure and porosity and had no toxic effect on mouse fibroblast NIH 3 T3 cells, proving their high biocompatibility. (C) 2018 Elsevier B.V. All rights reserved.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T. G., Vinogradova O. N., Zhila N. O., Kiselev E. G., Peterson I. V., Vasil’ev A. D., Sukovatyi A. G., Shishatskaya E. I.
Заглавие : Physicochemical properties of multicomponent polyhydroxyalkanoates: Novel aspects
Место публикации : Polym. Sci. Ser. A: Maik Nauka-Interperiodica Publishing, 2017. - Vol. 59, Is. 1. - С. 98-106. - ISSN 0965545X (ISSN) , DOI 10.1134/S0965545X17010163
Ключевые слова (''Своб.индексиров.''): glycols--medical problems--melting--molecular mass--monomers--polymers--chemical compositions--degree of crystallinity--degrees of crystallinity--multi-component polyhydroxyalkanoates--physicochemical property--polyhydroxyalkanoates--temperature intervals--thermal degradation temperatures--organic polymers
Аннотация: The physicochemical properties such as the degree of crystallinity and temperature and molecularmass characteristics of a number of polyhydroxyalkanoates of various chemical composition synthesized on a complex carbon substrate by bacteria Cupriavidus eutrophus В10646 have been investigated. Two-, three-, and four-component copolymer samples have different sets and ratios of monomers with various lengths of carbon chains: 3-hydroxybutyrate (3HB), 4-hydroxybutyrate (4HB), 3-hydroxyvalerate (3HV), 3-hydroxyhexanoate (3HH), 3-hydroxy-4-methyl valerate (3H4MV), and diethylene glycol (DEG). It has been shown that weight-average molar mass Мw and polydispersity vary in a wide range with no correlation existing with the composition of copolymer polyhydroxyalkanoates and that thermal stability is preserved in the temperature interval between the melting temperature and the thermal degradation temperature from 100 to 120–140°С. The composition and ratio of monomers most notably affect the degree of crystallinity of polyhydroxyalkanoates. Significant differences between the degrees of crystallinity of three- and four-component polyhydroxyalkanoates have been found for the first time. The degree of crystallinity for copolymers P(3HB/3HV/4HB) is 9–22%, and the degree of crystallinity for copolymers P(3HB/3HV/3HH) and P(3HB/3GV/3H4MV) is 41–63%; this value is close to the degree of crystallinity for diblock copolymers P(3HB)/DEG, which is 56–69%. For the four-component copolymers P(3HB/3GV/4HB/3HH), the degree of crystallinity is 30–41%. The values of Мw for the copolymers P(3HB/DEG) are inhomogeneous and the polymers contain fractions uneven with respect to molecular mass: a high-molecular-mass polymer (Мw from 2700 to 4900 kDa) and a low-molecular-mass polymer (Мw = 46–167 kDa). For the copolymers P(3HB)/DEG and P(3HB/3HV/3H4MV), two peaks are observed in the region of melting with the gap between these peaks being 4–20°С. All of the types of copolymer samples, regardless of the monomer ratio, show an increase in elongation at break against the background of a decrease in tensile stress and Young’s modulus, with these effects being pronounced to different extents. On the whole, the properties of multicomponent polyhydroxyalkanoates differ appreciably. © 2017, Pleiades Publishing, Ltd.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T.G., Plotnikov V.F., Shishatskaya E.I., Mironov P.V., Vasil'ev A.D.
Заглавие : Physicochemical properties of two-component polyhydroxyalkanoates [Poly(3HB/3HV)]
Колич.характеристики :9 с
Место публикации : Biofizika: MEZHDUNARODNAYA KNIGA, 2004. - Vol. 49, Is. 6. - P1038-1046. - ISSN 0006-3029
Примечания : Cited References: 21
Предметные рубрики: BACTERIAL POLYHYDROXYALKANOATES
POLYESTERS
Ключевые слова (''Своб.индексиров.''): polyhydroxyalkanoates--copolymers of hydroxybutyrate and hydroxyvalerate--structure--physicochemical properties
Аннотация: A series of two-component polyhydroxyalkanoates consisting of hydroxybutyrate and hydroxyvalerate monomer at different ratios were synthesized using the bacterium Ralstonia eutropha B5786. The properties of polyhydroxyalkanoates were compared with those of the homopolymer of hydroxybutyric acid by X-ray structure analysis, IR spectroscopy, differential scanning calorimetry, and viscosimetry. With an increase in the molar fraction of hydroxyvalerate, an equalization of the ratio of the crystalline and amorphous phases in the copolymer was observed. The degree of crystallinity of the polymer decreased from 70-80 to 45-50%; in the range of an increase in the hydroxyvalerate molar fraction from several to 25-30 mol %, the dependence was linear. The temperature characteristics, the melting temperature (T-m), and the degradation temperature (T-d) were lower in polyhydroxyalkanoates than in polyhydroxybutyrate, for which T-m and T-d were 168-170 and 260-265degreesC, respectively. In the copolymer, as the molar fraction of hydroxyvalerate grew, both parameters decreased. In the range of variation of monomer ratio studied, they decreased to 150-160 and 200-220degreesC, respectively. No distinct correlation between the composition of the polymer and its molecular mass was found.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sevastianov V.I., Perova N.V., Shishatskaya E.I., Kalacheva G.S., Volova T.G.
Заглавие : Production of purified polyhydroxyalkanoates (PHAs) for applications in contact with blood
Колич.характеристики :14 с
Место публикации : J. Biomater. Sci.-Polym. Ed.: VSP BV, 2003. - Vol. 14, Is. 10. - P1029-1042. - ISSN 0920-5063, DOI 10.1163/156856203769231547
Примечания : Cited References: 34
Предметные рубрики: BIODEGRADABLE POLYESTERS
POLYMERS
Ключевые слова (''Своб.индексиров.''): polyhydroxyalkanoates (phas)--polyhydroxybutyrate (phb)--poly(hydroxybutyrate-co-hydroxyvalerate) (phbv)--endotoxins--beta-hydroxy acids--hemocompatibility
Аннотация: Samples of olyhydroxyalkanoates (PHAs), polyhydroxybutyrate (PHB) and copolymers poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) with 4 and 18 mol% hydroxyvalerate, synthesized by the bacteria Ralstonia eutropha B5786, were investigated. PHA films in contact with blood did not activate the hemostasis system at the level of cell response, but they did activate the coagulation system and the complement reaction. To detect biologically-active components in the PHAs, a detailed analysis of the composition of the polymers was conducted. Gas chromatography-mass spectrometry revealed long-chain fatty acids (FAs) in the tested PHAs. Their total concentration in the polymer ranged from tenths of mol% to 2-3 mol%, depending on the purification method. C-16:0 constituted the largest proportion, up to 70%. Of the long-chain hydroxy acids, only beta-OH-C-14:0 was detected and it did not exceed 0.06 mol%. The analysis of the hemocompatibility properties of the PHAs purified by a specialized procedure, including the quantitative and morphological estimation of platelets adherent to the surface of polymer films, the plasma recalcification time and complement activation studies, indicated that PHB and PHBV can be used in contact with blood. It has been found out that the lipopolysaccharides of bacteria producing PHAs, which contain mostly long-chain hydroxy acids, can be the factor activating the hemostasis systems. Thus, the technology of PHA purification must satisfy rather stringent specific requirements.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T., Zhila N., Kiselev E., Shishatskaya E.
Заглавие : A study of synthesis and properties of poly-3-hydroxybutyrate/diethylene glycol copolymers
Место публикации : Biotechnol. Prog.: John Wiley and Sons Inc., 2016. - Vol. 32, Is. 4. - С. 1017-1028. - ISSN 87567938 (ISSN) , DOI 10.1002/btpr.2267
Ключевые слова (''Своб.индексиров.''): biocompatibility--biosynthesis--molecular weight--physicochemical and mechanical properties--poly(3-hydroxybutyrate)/diethylene glycol copolymers--biochemistry--biocompatibility--biosynthesis--cell culture--cell membranes--cells--cytology--fatty acids--glycols--molecular weight--american institute of chemical engineers--biological properties--chemical compositions--cytoplasmic membrane--degree of saturations--physico-chemical and mechanical properties--physiological effects--poly-3-hydroxybutyrate--biomechanics
Аннотация: This study investigates synthesis of poly(3-hydroxybutyrate)/diethylene glycol copolymers (P3HB/DEG) by Cupriavidus eutrophus B-10646 cells as related to DEG concentration in the medium and the time when it is added to the culture of cells synthesizing P3HB. The study determines the limits of physiological effect of DEG on C. eutrophus cells, showing that at DEG concentrations above 30 g/L, it inhibits cell growth, decreasing cell concentration and total P3HB/DEG yield and inducing an increase in the degree of saturation of fatty acids in lipids of cell cytoplasmic membrane. A series of copolymers containing different molar fractions of DEG (between 0.13 and 3.0 mol%) have been synthesized and their physicochemical, physical/mechanical, and biological properties have been investigated as related to the chemical composition and proportions of DEG monomers of the polymers. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1017–1028, 2016. © 2016 American Institute of Chemical Engineers
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T. G., Syrvacheva D. A., Zhila N. O., Sukovatiy A. G.
Заглавие : Synthesis of P(3HB-co-3HHx) copolymers containing high molar fraction of 3-hydroxyhexanoate monomer by Cupriavidus eutrophus B10646
Место публикации : J. Chem. Technol. Biotechnol. - 2016. - Vol. 91, Is. 2. - С. 416-425. - ISSN 02682575 (ISSN) , DOI 10.1002/jctb.4592
Ключевые слова (''Своб.индексиров.''): growth kinetics--physicochemical and mechanical properties--poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)--wild-type strain cupriavidus eutrophus b10646--biomaterials--biomechanics--chemical industry--cultivation--growth kinetics--mechanical properties--organic compounds--polymers--sodium--3-hydroxyhexanoate--bacterial strains--cultivation conditions--kinetic properties--physico-chemical and mechanical properties--physiological range--poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)--wild-type strain--strain
Аннотация: BACKGROUND: P(3HB-co-3HHx) copolymers are very promising biomaterials. The main challenge in the production of these polymers is to simultaneously achieve high cell biomass; high P(3HB-co-3HHx) content; and high molar fraction of 3HHx in P(3HB-co-3HHx). The most common approach to production of these copolymers is the use of recombinant bacterial strains. The purpose of this study was to optimize the process of production of P(3HB-co-3HHx) copolymers containing high molar fractions of 3HHx by using the wild-type strain Cupriavidus eutrophus B10646. RESULTS: Kinetic properties of C. eutrophus B10646 were studied during cultivation of the cells on substrates necessary for P(3HB-co-3HHx) synthesis: glucose, nitrogen, sodium hexanoate, and sodium acrylate. The physiological ranges of their effects were determined experimentally, and C. eutrophus B10646 was grown in culture media with different dosages of these substrates. P(3HB-co-3HHx) copolymers with different molar fractions of 3HHx, including high ones (12 to 68%), were synthesized, and their physicochemical and mechanical properties were investigated. CONCLUSION: For the first time, cultivation conditions of Cupriavidus eutrophus B10646 enabled production of high biomass yields (5-6gL-1) and high content of the polymer (60-75%) that contained high 3HHx molar fraction. By varying the 3HB/3HHx ratio, one can change physicochemical and mechanical properties of P(3HB-co-3HHx) copolymers. © 2014 Society of Chemical Industry © 2016 Society of Chemical Industry.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova, Tatiana G., Golubev, Alexey, I, Nemtsev, Ivan, V, Lukyanenko, Anna, V, Dudaev, Alexey E., Shishatskaya, Ekaterina, I
Заглавие : Laser Processing of Polymer Films Fabricated from PHAs Differing in Their Monomer Composition
Колич.характеристики :24 с
Коллективы : Russian Foundation for Basic Research/Regional State Autonomous Institution "Krasnoyarsk Regional Fund for the Support of Scientific and ScientificTechnical Activities" foundations [19-43-240012]; Ministry of Science and Higher Education of the Russian Federation [FSRZ-2020-0006]
Место публикации : Polymers: MDPI, 2021. - Vol. 13, Is. 10. - Ст.1553. - ISSN 2073-4360(eISSN), DOI 10.3390/polym13101553
Примечания : Cited References:87. - This work was supported by the Russian Foundation for Basic Research/Regional State Autonomous Institution "Krasnoyarsk Regional Fund for the Support of Scientific and ScientificTechnical Activities" foundations under Grant number 19-43-240012 (laser treatment and films properties) and by the State Assignment of the Ministry of Science and Higher Education of the Russian Federation No. FSRZ-2020-0006 (polymer synthesis).
Предметные рубрики: CHEMOMECHANICAL PROPERTIES
PHYSICOCHEMICAL PROPERTIES
SURFACE
Аннотация: The study reports results of using a CO2-laser in continuous wave (3 W; 2 m/s) and quasi-pulsed (13.5 W; 1 m/s) modes to treat films prepared by solvent casting technique from four types of polyhydroxyalkanoates (PHAs), namely poly-3-hydroxybutyrate and three copolymers of 3-hydroxybutyrate: with 4-hydroxybutyrate, 3-hydroxyvalerate, and 3-hydroxyhexanoate (each second monomer constituting about 30 mol.%). The PHAs differed in their thermal and molecular weight properties and degree of crystallinity. Pristine films differed in porosity, hydrophilicity, and roughness parameters. The two modes of laser treatment altered these parameters and biocompatibility in diverse ways. Films of P(3HB) had water contact angle and surface energy of 92 degrees and 30.8 mN/m, respectively, and average roughness of 144 nm. The water contact angle of copolymer films decreased to 80-56 degrees and surface energy and roughness increased to 41-57 mN/m and 172-290 nm, respectively. Treatment in either mode resulted in different modifications of the films, depending on their composition and irradiation mode. Laser-treated P(3HB) films exhibited a decrease in water contact angle, which was more considerable after the treatment in the quasi-pulsed mode. Roughness parameters were changed by the treatment in both modes. Continuous wave line-by-line irradiation caused formation of sintered grooves on the film surface, which exhibited some change in water contact angle (76-80 degrees) and reduced roughness parameters (to 40-45 mN/m) for most films. Treatment in the quasi-pulsed raster mode resulted in the formation of pits with no pronounced sintered regions on the film surface, a more considerably decreased water contact angle (to 67-76 degrees), and increased roughness of most specimens. Colorimetric assay for assessing cell metabolic activity (MTT) in NIH 3T3 mouse fibroblast culture showed that the number of fibroblasts on the films treated in the continuous wave mode was somewhat lower; treatment in quasi-pulsed radiation mode caused an increase in the number of viable cells by a factor of 1.26 to 1.76, depending on PHA composition. This is an important result, offering an opportunity of targeted surface modification of PHA products aimed at preventing or facilitating cell attachment.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T. G., Golubev A. I., Nemtsev I. V., Lukyanenko A. V., Dudaev A. E., Shishatskaya E. I.
Заглавие : Laser processing of polymer films fabricated from phas differing in their monomer composition
Место публикации : Polym.: MDPI AG, 2021. - Vol. 13, Is. 10. - Ст.1553. - ISSN 20734360 (ISSN), DOI 10.3390/polym13101553
Аннотация: The study reports results of using a CO2-laser in continuous wave (3 W; 2 m/s) and quasi-pulsed (13.5 W; 1 m/s) modes to treat films prepared by solvent casting technique from four types of polyhydroxyalkanoates (PHAs), namely poly-3-hydroxybutyrate and three copolymers of 3-hydroxybutyrate: with 4-hydroxybutyrate, 3-hydroxyvalerate, and 3-hydroxyhexanoate (each second monomer constituting about 30 mol.%). The PHAs differed in their thermal and molecular weight properties and degree of crystallinity. Pristine films differed in porosity, hydrophilicity, and roughness parameters. The two modes of laser treatment altered these parameters and biocompatibility in diverse ways. Films of P(3HB) had water contact angle and surface energy of 92? and 30.8 mN/m, respectively, and average roughness of 144 nm. The water contact angle of copolymer films decreased to 80–56? and surface energy and roughness increased to 41–57 mN/m and 172–290 nm, respectively. Treatment in either mode resulted in different modifications of the films, depending on their composition and irradiation mode. Laser-treated P(3HB) films exhibited a decrease in water contact angle, which was more considerable after the treatment in the quasi-pulsed mode. Roughness parameters were changed by the treatment in both modes. Continuous wave line-by-line irradiation caused formation of sintered grooves on the film surface, which exhibited some change in water contact angle (76–80? ) and reduced roughness parameters (to 40–45 mN/m) for most films. Treatment in the quasi-pulsed raster mode resulted in the formation of pits with no pronounced sintered regions on the film surface, a more considerably decreased water contact angle (to 67–76? ), and increased roughness of most specimens. Colorimetric assay for assessing cell metabolic activity (MTT) in NIH 3T3 mouse fibroblast culture showed that the number of fibroblasts on the films treated in the continuous wave mode was somewhat lower; treatment in quasi-pulsed radiation mode caused an increase in the number of viable cells by a factor of 1.26 to 1.76, depending on PHA composition. This is an important result, offering an opportunity of targeted surface modification of PHA products aimed at preventing or facilitating cell attachment. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova, Tatiana G., Kiselev, Evgeniy G., Demidenko, Alexey V., Zhila, Natalia O., Nemtsev, Ivan V., Lukyanenko, Anna V.
Заглавие : Production and Properties of Microbial Polyhydroxyalkanoates Synthesized from Hydrolysates of Jerusalem Artichoke Tubers and Vegetative Biomass
Колич.характеристики :25 с
Коллективы : Project "Agropreparations of the new generation: a strategy of construction and realization" [075-15-2021-626]; State Assignment of the Ministry of Science and Higher Education of the Russian Federation [FSRZ-2020-0006]
Место публикации : Polymers: MDPI, 2022. - Vol. 14, Is. 1. - Ст.132. - ISSN 2073-4360(eISSN), DOI 10.3390/polym14010132
Примечания : Cited References:93. - This study was financially supported by Project "Agropreparations of the new generation: a strategy of construction and realization" (Agreement No. 075-15-2021-626) in accordance with Resolution No. 220 of the Government of the Russian Federation of 9 April 2010, "On measures designed to attract leading scientists to the Russian institutions of higher learning" (polymer synthesis, properties), and by the State Assignment of the Ministry of Science and Higher Education of the Russian Federation No. FSRZ-2020-0006 (films production, surface properties).
Предметные рубрики: GLUCOSE-UTILIZING STRAIN
RALSTONIA-EUTROPHA
ASPERGILLUS-NIGER
ACID
Аннотация: One of the major challenges in PHA biotechnology is optimization of biotechnological processes of the entire synthesis, mainly by using new inexpensive carbon substrates. A promising substrate for PHA synthesis may be the sugars extracted from the Jerusalem artichoke. In the present study, hydrolysates of Jerusalem artichoke (JA) tubers and vegetative biomass were produced and used as carbon substrate for PHA synthesis. The hydrolysis procedure (the combination of aqueous extraction and acid hydrolysis, process temperature and duration) influenced the content of reducing substances (RS), monosaccharide contents, and the fructose/glucose ratio. All types of hydrolysates tested as substrates for cultivation of three strains-C. necator B-10646 and R. eutropha B 5786 and B 8562-were suitable for PHA synthesis, producing different biomass concentrations and polymer contents. The most productive process, conducted in 12-L fermenters, was achieved on hydrolysates of JA tubers (X = 66.9 g/L, 82% PHA) and vegetative biomass (55.1 g/L and 62% PHA) produced by aqueous extraction of sugars at 80 degrees C followed by acid hydrolysis at 60 degrees C, using the most productive strain, C. necator B-10646. The effects of JA hydrolysates on physicochemical properties of PHAs were studied for the first time. P(3HB) specimens synthesized from the JA hydrolysates, regardless of the source (tubers or vegetative biomass), hydrolysis conditions, and PHA producing strain employed, exhibited the 100-120 degrees C difference between the T-melt and T-degr, prevailing of the crystalline phase over the amorphous one (C-x between 69 and 75%), and variations in weight average molecular weight (409-480) kDa. Supplementation of the culture medium of C. necator B-10646 grown on JA hydrolysates with potassium valerate and epsilon-caprolactone resulted in the synthesis of P(3HB-co-3HV) and P(3HB-co-4HB) copolymers that had decreased degrees of crystallinity and molecular weights, which influenced the porosity and surface roughness of polymer films prepared from them. The study shows that JA hydrolysates used as carbon source enabled productive synthesis of PHAs, comparable to synthesis from pure sugars. The next step is to scale up PHA synthesis from JA hydrolysates and conduct the feasibility study. The present study contributes to the solution of the critical problem of PHA biotechnology-finding widely available and inexpensive substrates.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T., Kiselev E., Nemtsev I., Lukyanenko A., Sukovatyi A., Kuzmin A., Ryltseva G., Shishatskaya E.
Заглавие : Properties of degradable polyhydroxyalkanoates with different monomer compositions
Колич.характеристики :17 с
Коллективы : RFBRRussian Foundation for Basic Research (RFBR) [19-43-240012]; Ministry of Education and Science of the Russian FederationMinistry of Education and Science, Russian Federation [FSRZ-2020-0006]
Место публикации : Int. J. Biol. Macromol.: ELSEVIER, 2021. - Vol. 182. - С. 98-114. - ISSN 0141-8130, DOI 10.1016/j.ijbiomac.2021.04.008. - ISSN 1879-0003(eISSN)
Примечания : Cited References:106. - The part of the reported study on polymer synthesis and examinationwas funded by RFBR and KKRF [Grant No. 19-43-240012 "Biological and physical principles of production of new generation biomaterials"]. The work on production and investigation of polymer films was carried out as part of the State Assignment of the Ministry of Education and Science of the Russian Federation [Grant No. FSRZ-2020-0006].
Предметные рубрики: PALM KERNEL OIL
RALSTONIA-EUTROPHA
BIODEGRADABLE POLYMERS
Аннотация: Purpose: To synthesize and investigate polyhydroxyalkanoates (PHAs) with different monomer composition and percentages and polymer films prepared from them. Results: Various PHAs: homopolymer poly-3-hydroxybutyrate P(3HB) and 2-, 3-, and 4-component copolymers comprising various combinations of 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), 4-hydroxybutyrate (4HB), and 3-hydroxyhexanoate (3HHx) monomers were synthesized under specialized conditions. Relationships were found between the monomer composition of PHAs and their molecular-weight and thermal properties and degree of crystallinity. All copolymers had decreased weight average molecular weights, Mw (to 390-600 kDa), and increased values of polydispersity (3.2-4.6) compared to the P(3HB). PHA copolymers showed different thermal behavior: an insignificant decrease in Tmelt and the presence of the second peak in the melting region and changes in parameters of crystallization and glass transition. At the same time, they retained thermostability, and the difference between Tmelt and Tdegr was at least 100-120 degrees C. Incorporation of 4HB, 3HV, and 3HHx monomer units into the 3-hydroxybutyrate chain caused changes in the amorphous to crystalline ratio and decreased the degree of crystallinity (Cx) to 20-40%. According to the degree to which the monomers reduced crystallinity, they were ranked as follows: 4HB - 3HHx - 3HV. A unique set of films was produced; their surface properties and physical/mechanical properties were studied as dependent on PHA composition; monomers other than 3hydroxybutyrate were found to enhance hydrophilicity, surface development, and elasticity of polymer films. Conclusion: An innovative set of PHA copolymers was synthesized and solution-cast films were prepared from them; the copolymers and films were investigated as dependent on polymer chemical composition. Results obtained in the present study contribute to the solution of a critical issue of producing degradable polymer materials. (C) 2021 Elsevier B.V. All rights reserved.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhila N. O., Kalacheva G. S., Fokht V. V., Bubnova S. S., Volova T. G.
Заглавие : Biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by cupriavidus necator B-10646 from mixtures of oleic acid and 3-hydroxyvalerate precursors
Место публикации : J. Sib. Fed. Univ. - Biol.: Siberian Federal University, 2020. - Vol. 13, Is. 3. - С. 331-341. - ISSN 19971389 (ISSN), DOI 10.17516/1997-1389-0320
Аннотация: Polyhydroxyalkanoates have attracted much attention as biodegradable alternative to petroleum-based synthetic plastics. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] copolymer is one of the best characterized PHA copolymers because of its high commercial potential. However, commercial use of PHAs has been limited by their high price. One approach to reducing the cost of PHA production is to use inexpensive carbon sources (fatty acids, plant oils, etc.). The aim of this work was to study synthesis of P(3HB-co-3HV) by the Cupriavidus necator B-10646 bacterium grown on oleic acid and different biochemical precursors of 3HV. Bacterial cells were grown for 72 h at 30°C and 200 rpm on an incubator shaker. Salts of propionic or valeric acids were used as precursors of 3HV. The content and the composition of the polymer were determined by gas chromatography of fatty acid methyl esters. Lipids and polymer were extracted from biomass using the method of Folch. The addition of potassium propionate and valerate did not inhibit bacterial growth and polymer synthesis, the cell concentration and polymer content reaching 9.3-9.5 g/L and 80-83%, respectively. The addition of potassium valerate or propionate led to the synthesis of (P(3HB-co-3HV)) copolymer containing 21.2 and 14.3 mol% of 3HV, respectively. The number average molecular weight (Mn) of the polymer synthesized by the bacterium on oleic acid alone was 220 kDa; the polydispersity of the polymer was 3.5. The polymer synthesized in the presence of potassium valerate and propionate was characterized by a lower Mn (156-178 kDa) and a higher polydispersity of the polymer (4.4-4.9). The main fatty acids (FA) of intracellular lipids were oleic (33.26% of the total FA) and palmitic acid (27.48% of the total FA). The addition of potassium propionate or valerate did not cause any significant changes in the composition of the FA of intracellular lipids of the strain studied. This study demonstrates the ability of C. necator B-10646 to synthesize P(3HB-co-3HV) from mixtures of oleic acid and 3HV precursors. The data obtained can be used to develop and implement an economically feasible process of the P(3HB-co-3HV) production. © Siberian Federal University. All rights reserved.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shishatskaya, Ekaterina I., Menzyanova, Natalia G., Shumilova, Anna A.
Заглавие : The effect of the chemical composition and structure of polymer films made from resorbable polyhydroxyalkanoates on blood cell response
Колич.характеристики :11 с
Коллективы : Russian Science FoundationRussian Science Foundation (RSF) [17-15-01352]
Место публикации : Int. J. Biol. Macromol.: ELSEVIER, 2019. - Vol. 141. - С. 765-+. - ISSN 0141-8130, DOI 10.1016/j.ijbiomac.2019.09.015. - ISSN 1879-0003(eISSN)
Примечания : Cited References:57. - The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The study is supporting by the Russian Science Foundation, Project No 17-15-01352.
Предметные рубрики: 3-HYDROXYBUTYRATE
BIOCOMPATIBILITY
BIOSYNTHESIS
ADHESION
STENTS
Аннотация: Four PHA types were synthesized in the culture of Cupriavidus eutrophus B-10646 under special conditions, poly(3 hydroxybutyrate) [P(3HB)] and of copolymers, which contained 3HB monomers and 4 hydroxybutyrate (4HB), 3 hydroxyvalerate (3HV), or 3 hydroxyhexanoate (3HHx). All copolymers had the M-w of about 550-670 kDa, and the homopolymer P(3HB) had a significantly higher M-w - 920 kDa. P(3HB co 4HB) and P(3HB co 3HHx) had the lowest C-x (42 and 49%) while P(3HB co 3HV) and P(3HB) exhibited higher C-x values (76%). Polymer films were prepared from different PHAs. Electron microscopy showed differences in the surface microstructure of the films. Films prepared from the P(3HB) were more hydrophobic and the arithmetic mean surface roughness of 71-75 nm, than the copolymer films, which were hydrophilic (57-60 degrees) and had considerably higher roughness (158-177 nm). Blood parameters (hemoglobin and hemolysis) and response of the cells (erythrocytes, platelets, and monocytes) were studied in experiments with blood directly contacting the surface of the films of PHAs with different compositions. Cultivation of blood cells on polymer films did not cause any adverse effects on adhesion and morphology of all cell types. Results of studying blood cell response suggested that the films made from low-crystallinity copolymers containing 4 hydroxybutyrate and 3 hydroxyhexanoate were the best for contact with blood. (C) 2019 Elsevier B.V. All rights reserved.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shishatskaya E. I., Menzyanova N. G., Shumilova A. A.
Заглавие : The effect of the chemical composition and structure of polymer films made from resorbable polyhydroxyalkanoates on blood cell response
Место публикации : Int. J. Biol. Macromol.: Elsevier B.V., 2019. - Vol. 141. - С. 765-774. - ISSN 01418130 (ISSN) , DOI 10.1016/j.ijbiomac.2019.09.015
Аннотация: Four PHA types were synthesized in the culture of Cupriavidus eutrophus B-10646 under special conditions, poly(3?hydroxybutyrate) [P(3HB)] and of copolymers, which contained 3HB monomers and 4?hydroxybutyrate (4HB), 3?hydroxyvalerate (3HV), or 3?hydroxyhexanoate (3HHx). All copolymers had the Mw of about 550–670 kDa, and the homopolymer P(3HB) had a significantly higher Mw – 920 kDa. P(3HB?co?4HB) and P(3HB?co?3HHx) had the lowest Cx (42 and 49%) while P(3HB?co?3HV) and P(3HB) exhibited higher Cx values (76%). Polymer films were prepared from different PHAs. Electron microscopy showed differences in the surface microstructure of the films. Films prepared from the P(3HB) were more hydrophobic and the arithmetic mean surface roughness of 71–75 nm, than the copolymer films, which were hydrophilic (57–60°) and had considerably higher roughness (158–177 nm). Blood parameters (hemoglobin and hemolysis) and response of the cells (erythrocytes, platelets, and monocytes) were studied in experiments with blood directly contacting the surface of the films of PHAs with different compositions. Cultivation of blood cells on polymer films did not cause any adverse effects on adhesion and morphology of all cell types. Results of studying blood cell response suggested that the films made from low-crystallinity copolymers containing 4?hydroxybutyrate and 3?hydroxyhexanoate were the best for contact with blood. © 2019 Elsevier B.V.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T., Kiselev E., Nemtsev I., Lukyanenko А., Sukovatyi A., Kuzmin A., Ryltseva G., Shishatskaya E.
Заглавие : Properties of degradable polyhydroxyalkanoates with different monomer compositions
Место публикации : Int. J. Biol. Macromol.: Elsevier B.V., 2021. - Vol. 182. - С. 98-114. - ISSN 01418130 (ISSN), DOI 10.1016/j.ijbiomac.2021.04.008
Аннотация: Purpose: To synthesize and investigate polyhydroxyalkanoates (PHAs) with different monomer composition and percentages and polymer films prepared from them. Results: Various PHAs: homopolymer poly-3-hydroxybutyrate P(3HB) and 2-, 3-, and 4-component copolymers comprising various combinations of 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), 4-hydroxybutyrate (4HB), and 3-hydroxyhexanoate (3HHx) monomers were synthesized under specialized conditions. Relationships were found between the monomer composition of PHAs and their molecular-weight and thermal properties and degree of crystallinity. All copolymers had decreased weight average molecular weights, Mw (to 390–600 kDa), and increased values of polydispersity (3.2–4.6) compared to the P(3HB). PHA copolymers showed different thermal behavior: an insignificant decrease in Tmelt and the presence of the second peak in the melting region and changes in parameters of crystallization and glass transition. At the same time, they retained thermostability, and the difference between Tmelt and Tdegr was at least 100–120 °C. Incorporation of 4HB, 3HV, and 3HHx monomer units into the 3-hydroxybutyrate chain caused changes in the amorphous to crystalline ratio and decreased the degree of crystallinity (Cx) to 20–40%. According to the degree to which the monomers reduced crystallinity, they were ranked as follows: 4HB – 3HHx – 3HV. A unique set of films was produced; their surface properties and physical/mechanical properties were studied as dependent on PHA composition; monomers other than 3-hydroxybutyrate were found to enhance hydrophilicity, surface development, and elasticity of polymer films. Conclusion: An innovative set of PHA copolymers was synthesized and solution-cast films were prepared from them; the copolymers and films were investigated as dependent on polymer chemical composition. Results obtained in the present study contribute to the solution of a critical issue of producing degradable polymer materials. © 2021 Elsevier B.V.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kiselev E. G., Vasiliev A. D., Volova T. G.
Заглавие : Synthesis and characterization of multicomponent PHAs
Место публикации : J. Sib. Fed. Univ. - Biol.: Siberian Federal University, 2021. - Vol. 14, Is. 1. - С. 97-113. - ISSN 19971389 (ISSN), DOI 10.17516/1997-1389-0325
Примечания : Cited By :1
Аннотация: Cupriavidus necator B10646 bacterial cells were cultivated in the mode of synthesis of the reserve polyhydroxyalkanoates (PHAs) in the growth medium that contained, in addition to glucose as the main substrate, precursor substrates of the monomers of various monocarboxylic acids - salts of valeric and hexanoic acids, propionate, and ?-butyrolactone. PHA terpolymers and quaterpolymers with different compositions and proportions of monomers were synthesized, and their physicochemical properties were studied. The terpolymers were composed of monomers of 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), 4-hydroxybutyrate (4HB), or 3-hydroxyhexanoate (3HHx) and had the following compositions: P(3HB/3HB/4HHx) and P(3HB/3HV/4HHx). The quaterpolymers had the following composition: P(3HB/3HV/4HB/3HHx). All copolymer samples, regardless of the composition and proportions of monomers, had lower molecular weights and higher polydispersity values compared to the highly crystalline 3-hydroxybutyrate homopolymer, but retained thermal stability properties, with a difference between the melting point and thermal degradation of at least 100-110 °C. The inclusion of 3HV, 4HB, and 3HHx monomers in the C-chain of 3HB caused changes in the crystalline to amorphous phase ratio and a significant decrease in the degree of crystallinity (Cx), which depended on the type of monomers and their contents in the copolymer. The maximum decrease in Cx (9-17 %) was detected in the P(3HB/3HV/4HB) terpolymer and the P(3HB/3HV/4HB/3HHx) quaterpolymer (30-36 %). The study confirms that there is the possibility of synthesizing polymers with various compositions, including new ones, which differ significantly in their basic properties. © Siberian Federal University. All rights reserved.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Shishatskaya E.I., Volova T.G., Gordeev S.A., Puzyr A.P.
Заглавие : Degradation of P(3HB) and P(3HB-co-3HV) in biological media
Место публикации : Journal of Biomaterials Science, Polymer Edition. - 2005. - Vol. 16, Is. 5. - С. 643-657. - ISSN 09205063 (ISSN) , DOI 10.1163/1568562053783678
Ключевые слова (''Своб.индексиров.''): degradation rate--fiber properties--morphology--poly(hydroxybutyrate-co-hydroxyvalerate) (p(3hb-co-3hv))--polyhydroxyalkanoates(phas)--polyhydroxybutyrate (p(3hb))--copolymers--degradation--differential scanning calorimetry--enzymes--morphology--scanning electron microscopy--tensile strength--tissue--transmission electron microscopy--degradation rate--fiber properties--polyhydroxyalkanoates (phas)--polyhydroxybutyrate (p(3hb))--biopolymers--buffer--copolymer--poly(3 hydroxybutyric acid)--polyhydroxybutyrate hydroxyvalerate copolymer--unclassified drug--animal experiment--animal model--animal tissue--article--biodegradation--controlled study--crystal structure--fiber--giant cell--in vitro study--in vivo study--macrophage--morphology--nonhuman--ph--priority journal--rat--structure analysis--tensile strength--tissue water--weight reduction--animals--biodegradation, environmental--buffers--humans--hydrogen-ion concentration--hydroxybutyrates--macrophages--microscopy, electron, scanning--microscopy, electron, transmission--muscle, skeletal--polyesters--rats--rats, wistar
Аннотация: The biodegradability of oriented fibers made of polyhydroxybutyrate (P(3HB)) and its co-polymer with ?-hydroxyvalerate (P(3HB-co-3HV)) was investigated in buffer solutions and in biological media in vitro and in vivo. The fibers of both polymer types demonstrated resistance to hydrolytic degradation in buffer solutions at 38В°C and pH from 4.5 to 7.0 (for up to 180 days). It has been found that the biodegradation of the fibers in vitro in blood and serum and in vivo is accompanied by weight losses and minor changes in the microstructure with no significant losses in the tensile strength over a long time (up to 180 days). The biodegradation rate of the less crystalline co-polymer P(3HB-co-3HV) fibers was 1.4-2.0-times higher than that of the homopolymer P(3HB). It has also been shown that the degradation of the fibers in vivo is influenced both by tissue fluid enzymes and cells (macrophages and foreign-body giant cells). The fibers were eroded on the surface only with no gross defects and no dramatic effects on their mechanical performance. В© VSP 2005.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T.G., Kalacheva G.S.
Заглавие : The synthesis of hydroxybutyrate and hydroxyvalerate copolymers by the bacterium Ralstonia eutropha
Место публикации : Mikrobiologiya. - 2005. - Vol. 74, Is. 1. - С. 63-69. - ISSN 00263656 (ISSN)
Ключевые слова (''Своб.индексиров.''): ?-ketothiolase--controlled synthesis--poly(hydroxybutyrate-co-hydroxyvalerate)--ralstonia eutropha--bacteria (microorganisms)--cupriavidus necator--acetoacetyl coenzyme a--acetyl coenzyme a acyltransferase--acyl coenzyme a--acyltransferase--butyric acid derivative--carbon dioxide--fructose--hydrogen--poly(3 hydroxybutyrate) co (3 hydroxyvalerate)--poly(3-hydroxyalkanoic acid) synthase--poly(3-hydroxybutyrate)-co-(3-hydroxyvalerate)--polyester--polyhydroxyalkanoate synthase--valeric acid derivative--article--chemistry--crystallization--culture medium--metabolism--wautersia eutropha--acetyl-coa c-acyltransferase--acyl coenzyme a--acyltransferases--butyrates--carbon dioxide--crystallization--culture media--cupriavidus necator--fructose--hydrogen--polyesters--valerates
Аннотация: The paper deals with the study of the synthesis of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) copolymers by the bacterium Ralstonia eutropha B-5786 grown under different carbon nutrition conditions (growth on carbon dioxide, fructose, and CO2-valerate and fructose-valerate mixtures). The parameters to be analyzed included the yield of biomass, the yield, synthesis rate, and composition of copolymers, the activity of the key enzymes of polyhydroxyalkanoate (PHA) synthesis (?-ketothiolase, acetoacetyl-CoA reductase, and PHA synthase), the maximum tolerable concentration of valerate to the bacterium, and the conditions that govern the incorporation of hydroxyvalerate to copolymers. This allowed the relationship between cultivation conditions and the proportion of monomers in the copolymers to be deduced. We were able to synthesize a range of 3HB/3HV copolymers and found that the thermal characteristics and the degree of crystallinity of these copolymers depend on the molar fraction of 3HV.
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