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Sample records for glucose glycerol 3-hydroxybutyrate

  1. Evaluation of the addition of glycerol to Cupriavidus necator culture medium over Poly(3-hydroxybutyrate) production

    OpenAIRE

    Apati, Giannini Paszinick; Kelbert, Maikon; Sombrio, Bruna Regina; Schneider, Andrea Lima dos Santos; Garcia, Michele Cristina Formolo; Furigo Junior, Agenor; Pezzin, Ana Paula Testa

    2018-01-01

    ABSTRACT Glycerol was used as a source of additional carbon in the production of Poly(3-hydroxybutyrate) (P(3HB)). The inverted sugar and glycerol concentrations and the temperature of the Cupriavidus necator culture medium were evaluated using a Central Composite Rotational Design (CCRD). The results showed that the increase in temperature and sugar concentration led to an increase in production and P(3HB) accumulation and when 15 g L-1 of glycerol was added better results were obtained, how...

  2. Production of poly(3-hydroxypropionate) and poly(3-hydroxybutyrate-co-3-hydroxypropionate) from glucose by engineering Escherichia coli

    DEFF Research Database (Denmark)

    Meng, De-Chuan; Wang, Ying; Wu, Linping

    2015-01-01

    Saccharomyces cerevisiae that catalyzes formation of glycerol from glucose, and genes coding glycerol dehydratase (dhaB123) with its reactivating factors (gdrAB) from Klebsiella pneumoniae that transfer glycerol to 3-hydroxypropionaldehyde, as well as gene encoding propionaldehyde dehydrogenase (pdup) from...... reductase, were introduced into the above P3HP producing recombinant E. coli, copolymers poly(3-hydroxybutyrate-co-3-hydroxypropionate) (P3HB3HP) were synthesized from glucose as a sole carbon source. The above E. coli recombinants grown on glucose LB medium successfully produced 5 g/L cell dry weight...

  3. Sunflower-based biorefinery: poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) production from crude glycerol, sunflower meal and levulinic acid.

    Science.gov (United States)

    Kachrimanidou, Vasiliki; Kopsahelis, Nikolaos; Papanikolaou, Seraphim; Kookos, Ioannis K; De Bruyn, Mario; Clark, James H; Koutinas, Apostolis A

    2014-11-01

    Polyhydroxybutyrate (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] production was developed in bioreactor cultures using the strain Cupriavidus necator DSM 7237 cultivated on crude glycerol, sunflower meal (SFM) hydrolysates and levulinic acid as the sole fermentation feedstocks. Bacterial growth and PHB production was influenced significantly by the free amino nitrogen and inorganic phosphorus content of the SFM hydrolysate. Fed-batch bioreactor fermentations led to the production of 27gL(-1) PHB with an intracellular content of 72.9% (w/w). Continuous feeding of levulinic acid led to the production of up to 23.4gL(-1) P(3HB-co-3HV) with an intracellular content of 66.4% (w/w) and a 3HV content of 22.5mol%. A maximum 3HV content of 31mol% was achieved at earlier fermentation time (53h). Thus, levulinic acid could be combined with biodiesel industry by-products for the production of high P(3HB-co-3HV) concentration, intracellular content and industrially useful 3HV content. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Valorization of waste glycerol for the production of poly (3-hydroxybutyrate) and poly (3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer by Cupriavidus necator and extraction in a sustainable manner.

    Science.gov (United States)

    Gahlawat, Geeta; Soni, Sanjeev Kumar

    2017-11-01

    Glycerol is a by-product of many industrial processes and huge amounts of it are generated in the form of waste, thereby necessitating a search for the method of its disposal. An interesting solution is the valorization of crude glycerol into value added product such as polyhydroxyalkanoates (PHAs). The feasibility of producing PHAs by Cupriavidus necator was evaluated using crude glycerol (WG). Various cultivation strategies were designed for the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer by adding different organic acids as precursors at different concentrations levels. Batch cultivation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) production showed accumulation of 6.76g/L biomass containing 4.84g/L copolymer on WG with a maximum 3-hydroxyvalerate content of 24.6mol%. PHAs extraction using a non-toxic and recyclable solvent, 1,2 propylene carbonate, showed the highest recovery yield (90%) and purity (93%) at 120°C temperature and 30min incubation. This is the first report on jatropha based glycerol valorization for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) production coupled with extraction using non-toxic solvent. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Biosynthesis of poly(glycolate-co-lactate-co-3-hydroxybutyrate) from glucose by metabolically engineered Escherichia coli.

    Science.gov (United States)

    Li, Zheng-Jun; Qiao, Kangjian; Shi, Weichao; Pereira, Brian; Zhang, Haoran; Olsen, Bradley D; Stephanopoulos, Gregory

    2016-05-01

    Metabolically engineered Escherichia coli strains were constructed to effectively produce novel glycolate-containing biopolymers from glucose. First, the glyoxylate bypass pathway and glyoxylate reductase were engineered such as to generate glycolate. Second, glycolate and lactate were activated by the Megasphaera elsdenii propionyl-CoA transferase to synthesize glycolyl-CoA and lactyl-CoA, respectively. Third, β-ketothiolase and acetoacetyl-CoA reductase from Ralstonia eutropha were introduced to synthesize 3-hydroxybutyryl-CoA from acetyl-CoA. At last, the Ser325Thr/Gln481Lys mutant of polyhydroxyalkanoate (PHA) synthase from Pseudomonas sp. 61-3 was over-expressed to polymerize glycolyl-CoA, lactyl-CoA and 3-hydroxybutyryl-CoA to produce poly(glycolate-co-lactate-co-3-hydroxybutyrate). The recombinant E. coli was able to accumulate the novel terpolymer with a titer of 3.90g/l in shake flask cultures. The structure of the resulting polymer was chemically characterized by proton NMR analysis. Assessment of thermal and mechanical properties demonstrated that the produced terpolymer possessed decreased crystallinity and improved toughness, in comparison to poly(3-hydroxybutyrate) homopolymer. This is the first study reporting efficient microbial production of poly(glycolate-co-lactate-co-3-hydroxybutyrate) from glucose. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  6. Production and characterization of poly-3-hydroxybutyrate from crude glycerol by Bacillus sphaericus NII 0838 and improving its thermal properties by blending with other polymers

    Directory of Open Access Journals (Sweden)

    Raveendran Sindhu

    2011-08-01

    Full Text Available The aim of this work was to study the production of poly-3-hydroxybutyrate (PHB under nitrogen limited conditions by Bacillus sphaericus NII 0838 using crude glycerol from biodiesel industry as sole carbon source. Effect of various process parameters on PHB production such as glycerol concentration, inoculum size and pH of the medium were optimized. Characterization of extracted PHB was carried out by FT-IR, ¹H and 13C NMR. Results showed that the bacterial culture accumulated about 31% PHB in crude glycerol medium. The extracted PHB was blended with other polymers to improve its physical characteristics. The thermal properties of the polymer like melting temperature (Tm and heat of fusion (ΔHf were determined using DSC.

  7. Magnesium Affects Poly(3-hydroxybutyrate-co-4-hydroxybutyrate Content and Composition by Affecting Glucose Uptake in Delftia acidovorans

    Directory of Open Access Journals (Sweden)

    Lee, W. H.

    2007-01-01

    Full Text Available Precise control of polyhydroxyalkanoate (PHA composition is necessary in order to synthesize polymers with specific properties. Among the various types of PHA that have been identified, those that contain 4-hydroxybutyrate (4HB monomers are especially useful in the medical and pharmaceutical fields as absorbable biomaterial. In this study, we have investigated the effect of magnesium concentration on the biosynthesis of poly(3-hydroxybutyrate-co-4-hydroxybutyrate [P(3HB-co-4HB] by Delftia acidovorans DS-17. Our results show that, magnesium affects the copolymer content and composition by affecting glucose uptake from the culture medium. Higher concentrations of magnesium resulted in lower molar fractions of 3HB in the copolymer and reduced uptake of glucose. The results show for the first time that magnesium may be used to achieve fine control of biologically synthesized PHA copolymer composition.

  8. Cultivation strategies for production of (R)-3-hydroxybutyric acid from simultaneous consumption of glucose, xylose and arabinose by Escherichia coli.

    Science.gov (United States)

    Jarmander, Johan; Belotserkovsky, Jaroslav; Sjöberg, Gustav; Guevara-Martínez, Mónica; Pérez-Zabaleta, Mariel; Quillaguamán, Jorge; Larsson, Gen

    2015-04-11

    Lignocellulosic waste is a desirable biomass for use in second generation biorefineries. Up to 40% of its sugar content consist of pentoses, which organisms either take up sequentially after glucose depletion, or not at all. A previously described Escherichia coli strain, PPA652ara, capable of simultaneous consumption of glucose, xylose and arabinose was in the present work utilized for production of (R)-3-hydroxybutyric acid (3HB) from a mixture of glucose, xylose and arabinose. The Halomonas boliviensis genes for 3HB production were for the first time cloned into E. coli PPA652ara, leading to product secretion directly into the medium. Process design was based on comparisons of batch, fed-batch and continuous cultivation, where both excess and limitation of the carbon mixture was studied. Carbon limitation resulted in low specific productivity of 3HB (sugars were consumed. An industrial 3HB production process is proposed to be divided into a growth and a production phase, and nitrogen depletion/limitation is a potential strategy to maximize the yield of 3HB/CDW in the latter. The specific productivity of 3HB reported here from glucose, xylose and arabinose by E. coli is further comparable to the current state of the art for production from glucose sources.

  9. Metabolic engineering of Escherichia coli for the synthesis of the quadripolymer poly(glycolate-co-lactate-co-3-hydroxybutyrate-co-4-hydroxybutyrate) from glucose.

    Science.gov (United States)

    Li, Zheng-Jun; Qiao, Kangjian; Che, Xue-Mei; Stephanopoulos, Gregory

    2017-11-01

    Escherichia coli was metabolically engineered to effectively produce a series of biopolymers consisted of four types of monomers including glycolate, lactate, 3-hydroxybutyrate and 4-hydroxybutyrate from glucose as the carbon source. The biosynthetic route of novel quadripolymers was achieved by the overexpression of a range of homologous and heterologous enzymes including isocitrate lyase, isocitrate dehydrogenase kinase/phosphatase, glyoxylate/hydroxypyruvate reductase, propionyl-CoA transferase, β-ketothiolase, acetoacetyl-CoA reductase, succinate semialdehyde dehydrogenase, 4-hydroxybutyrate dehydrogenase, CoA transferase and PHA synthase. In shake flask cultures using Luria-Bertani medium supplemented with glucose, the recombinant E. coli reached 7.10g/l cell dry weight with 52.60wt% biopolymer content. In bioreactor study, the final cell dry weight was 19.61g/l, containing 14.29g/l biopolymer. The structure of the produced polymer was chemically characterized by proton NMR analysis. Assessment of thermal and mechanical properties demonstrated that the quadripolymer possessed decreased crystallinity and improved toughness, in comparison to poly-3-hydroxybutyrate homopolymer. This is the first study reporting efficient microbial production of the quadripolymer poly(glycolate-co-lactate-co-3-hydroxybutyrate-co-4-hydroxybutyrate) from glucose. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  10. Metabolic engineering of Escherichia coli for biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from glucose.

    Science.gov (United States)

    Yang, Jung Eun; Choi, Yong Jun; Lee, Se Jin; Kang, Kyoung-Hee; Lee, Hyuk; Oh, Young Hoon; Lee, Seung Hwan; Park, Si Jae; Lee, Sang Yup

    2014-01-01

    The Escherichia coli XL1-blue strain was metabolically engineered to synthesize poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] through 2-ketobutyrate, which is generated via citramalate pathway, as a precursor for propionyl-CoA. Two different metabolic pathways were examined for the synthesis of propionyl-CoA from 2-ketobutyrate. The first pathway is composed of the Dickeya dadantii 3937 2-ketobutyrate oxidase or the E. coli pyruvate oxidase mutant (PoxB L253F V380A) for the conversion of 2-ketobutyrate into propionate and the Ralstonia eutropha propionyl-CoA synthetase (PrpE) or the E. coli acetyl-CoA:acetoacetyl-CoA transferase for further conversion of propionate into propionyl-CoA. The second pathway employs pyruvate formate lyase encoded by the E. coli tdcE gene or the Clostridium difficile pflB gene for the direct conversion of 2-ketobutyrate into propionyl-CoA. As the direct conversion of 2-ketobutyrate into propionyl-CoA could not support the efficient production of P(3HB-co-3HV) from glucose, the first metabolic pathway was further examined. When the recombinant E. coli XL1-blue strain equipped with citramalate pathway expressing the E. coli poxB L253F V380A gene and R. eutropha prpE gene together with the R. eutropha PHA biosynthesis genes was cultured in a chemically defined medium containing 20 g/L of glucose as a sole carbon source, P(3HB-co-2.3 mol% 3HV) was produced up to the polymer content of 61.7 wt.%. Moreover, the 3HV monomer fraction in P(3HB-co-3HV) could be increased up to 5.5 mol% by additional deletion of the prpC and scpC genes, which are responsible for the metabolism of propionyl-CoA in host strains.

  11. Radiometric assays for glycerol, glucose, and glycogen

    International Nuclear Information System (INIS)

    Bradley, D.C.; Kaslow, H.R.

    1989-01-01

    We have developed radiometric assays for small quantities of glycerol, glucose and glycogen, based on a technique described by Thorner and Paulus for the measurement of glycerokinase activity. In the glycerol assay, glycerol is phosphorylated with [32P]ATP and glycerokinase, residual [32P]ATP is hydrolyzed by heating in acid, and free [32P]phosphate is removed by precipitation with ammonium molybdate and triethylamine. Standard dose-response curves were linear from 50 to 3000 pmol glycerol with less than 3% SD in triplicate measurements. Of the substances tested for interference, only dihydroxyacetone gave a slight false positive signal at high concentration. When used to measure glycerol concentrations in serum and in media from incubated adipose tissue, the radiometric glycerol assay correlated well with a commonly used spectrophotometric assay. The radiometric glucose assay is similar to the glycerol assay, except that glucokinase is used instead of glycerokinase. Dose response was linear from 5 to 3000 pmol glucose with less than 3% SD in triplicate measurements. Glucosamine and N-acetylglucosamine gave false positive signals when equimolar to glucose. When glucose concentrations in serum were measured, the radiometric glucose assay agreed well with hexokinase/glucose-6-phosphate dehydrogenase (H/GDH)-based and glucose oxidase/H2O2-based glucose assays. The radiometric method for glycogen measurement incorporates previously described isolation and digestion techniques, followed by the radiometric assay of free glucose. When used to measure glycogen in mouse epididymal fat pads, the radiometric glycogen assay correlated well with the H/GDH-based glycogen assay. All three radiometric assays offer several practical advantages over spectral assays

  12. Regional cerebral effects of ketone body infusion with 3-hydroxybutyrate in humans: Reduced glucose uptake, unchanged oxygen consumption and increased blood flow by positron emission tomography. A randomized, controlled trial.

    Science.gov (United States)

    Svart, Mads; Gormsen, Lars C; Hansen, Jakob; Zeidler, Dora; Gejl, Michael; Vang, Kim; Aanerud, Joel; Moeller, Niels

    2018-01-01

    Ketone bodies are neuroprotective in neurological disorders such as epilepsy. We randomly studied nine healthy human subjects twice-with and without continuous infusion of 3-hydroxybutyrate-to define potential underlying mechanisms, assessed regionally (parietal, occipital, temporal, cortical grey, and frontal) by PET scan. During 3-hydroxybutyrate infusions concentrations increased to 5.5±0.4 mmol/l and cerebral glucose utilisation decreased 14%, oxygen consumption remained unchanged, and cerebral blood flow increased 30%. We conclude that acute 3-hydroxybutyrate infusion reduces cerebral glucose uptake and increases cerebral blood flow in all measured brain regions, without detectable effects on cerebral oxygen uptake though oxygen extraction decreased. Increased oxygen supply concomitant with unchanged oxygen utilisation may contribute to the neuroprotective effects of ketone bodies.

  13. Redox driven metabolic tuning: carbon source and aeration affect synthesis of poly(3-hydroxybutyrate) in Escherichia coli.

    Science.gov (United States)

    Nikel, Pablo I; de Almeida, Alejandra; Giordano, Andrea M; Pettinari, M Julia

    2010-01-01

    Growth and polymer synthesis were studied in a recombinant E. coli strain carrying phaBAC and phaP of Azotobacter sp. strain FA8 using different carbon sources and oxygen availability conditions. The results obtained with glucose or glycerol were completely different, demonstrating that the metabolic routes leading to the synthesis of the polymer when using glycerol do not respond to environmental conditions such as oxygen availability in the same way as they do when other substrates, such as glucose, are used. When cells were grown in a bioreactor using glucose the amount of polymer accumulated at low aeration was reduced by half when compared to high aeration, while glycerol cultures produced at low aeration almost twice the amount of polymer synthesized at the higher aeration condition. The synthesis of other metabolic products, such as ethanol, lactate, formate and acetate, were also affected by both the carbon source used and aeration conditions. In glucose cultures, lactate and formate production increased in low agitation compared to high agitation, while poly(3-hydroxybutyrate) synthesis decreased. In glycerol cultures, the amount of acids produced also increased when agitation was lowered, but carbon flow was mostly redirected towards ethanol and poly(3-hydroxybutyrate). These results indicated that carbon partitioning differed depending on both carbon source and oxygen availability, and that aeration conditions had different effects on the synthesis of the polymer and other metabolic products when glucose or glycerol were used. © 2010 Landes Bioscience

  14. Glucose turnover, gluconeogenesis from glycerol, and estimation of net glucose cycling in cancer patients

    International Nuclear Information System (INIS)

    Lundholm, K.; Edstroem, S.; Karlberg, I.; Ekman, L.; Schersten, T.

    1982-01-01

    A double isotope method was used in patients with progressive malignancy and in control patients to measure: glucose turnover, conversion rate of carbon skeleton of glycerol into glucose, and the interorgan cycling of glucose carbons (Cori-cycle plus alanine-glucose cycle). [U- 14 C]glycerol and [6- 3 H]glucose were given intravenously as a single dose injection. The time course of the specific radioactivities of [6- 3 H] and [U- 14 C]glucose was followed in blood. The pool size and the turnover rate of glucose were increased in the cancer group as compared with the control patients. The net recycling of glucose carbons was not increased in the cancer group, despite the increased turnover of glucose. The alterations in the metabolism of glucose did not correlate with the plasma levels of insulin or thyroid hormones (T4, T3, rT3) neither in the entire cancer group nor in those cancer patients who were repeatedly investigated at different intervals of time. The turnover rate of glucose in the cancer patients correlated inversely to their body weight index. The gluconeogenesis rate, given as the fractional conversion rate of the injected radioactive dose of [ 14 C]glycerol, or as mol glucose . kg body weight-1 . day-1, was increased in the cancer group, but still contributed only 3% of the glucose turnover rate in both cancer and control patients. We conclude that an increased gluconeogenesis from glycerol is not significant in terms of energy expenditure in patients with progressive malignancy, as has previously been concluded for the gluconeogenesis from alanine. It seems that increased turnover of glucose may contribute to inappropriately high energy expenditure in cancer patients

  15. Glucose and glycerol concentrations and their tracer enrichment measurements using liquid chromatography tandem mass spectrometry

    DEFF Research Database (Denmark)

    Bornø, Andreas; Foged, Lene; van Hall, Gerrit

    2014-01-01

    The present study describes a new liquid chromatography tandem mass spectrometry method for high-throughput quantification of glucose and glycerol in human plasma using stable isotopically labeled internal standards and is suitable for simultaneous measurements of glucose and glycerol enrichments...... in connection to in vivo metabolic studies investigating glucose turnover and lipolytic rate. Moreover, in order to keep up with this new fast analysis, simple derivatization procedures have been developed. Prior to analysis, glucose and glycerol were derivatized using benzoyl chloride in order to form...... benzoylated derivatives via new simplified fast procedures. For glucose, two internal standards were evaluated, [U-(13) C(6)]glucose and [U-(13) C(6), D(7)]glucose, and for glycerol, [U-(13) C(3), D(8)]glycerol was used. The method was validated by means of calibration curves, quality control samples...

  16. Dynamical modeling of liver Aquaporin-9 expression and glycerol permeability in hepatic glucose metabolism.

    Science.gov (United States)

    Gena, Patrizia; Buono, Nicoletta Del; D'Abbicco, Marcello; Mastrodonato, Maria; Berardi, Marco; Svelto, Maria; Lopez, Luciano; Calamita, Giuseppe

    2017-01-01

    Liver is crucial in the homeostasis of glycerol, an important metabolic intermediate. Plasma glycerol is imported by hepatocytes mainly through Aquaporin-9 (AQP9), an aquaglyceroporin channel negatively regulated by insulin in rodents. AQP9 is of critical importance in glycerol metabolism since hepatic glycerol utilization is rate-limited at the hepatocyte membrane permeation step. Glycerol kinase catalyzes the initial step for the conversion of the imported glycerol into glycerol-3-phosphate, a major substrate for de novo synthesis of glucose (gluconeogenesis) and/or triacyglycerols (lipogenesis). A model addressing the glucose-insulin system to describe the hepatic glycerol import and metabolism and the correlation with the glucose homeostasis is lacking so far. Here we consider a system of first-order ordinary differential equations delineating the relevance of hepatocyte AQP9 in liver glycerol permeability. Assuming the hepatic glycerol permeability as depending on the protein levels of AQP9, a mathematical function is designed describing the time course of the involvement of AQP9 in mouse hepatic glycerol metabolism in different nutritional states. The resulting theoretical relationship is derived fitting experimental data obtained with murine models at the fed, fasted or re-fed condition. While providing useful insights into the dynamics of liver AQP9 involvement in male rodent glycerol homeostasis our model may be adapted to the human liver serving as an important module of a whole body-model of the glucose metabolism both in health and metabolic diseases. Copyright © 2016 Elsevier GmbH. All rights reserved.

  17. Model studies on acrylamide generation from glucose/asparagine in aqueous glycerol

    DEFF Research Database (Denmark)

    Hedegaard, Rikke Susanne Vingborg; Frandsen, Henrik Lauritz; Granby, Kit

    2007-01-01

    Acrylamide formation from asparagine and glucose in different ratios in neutral glycerol/water mixtures was found to increase with decreasing water activity (0.33......Acrylamide formation from asparagine and glucose in different ratios in neutral glycerol/water mixtures was found to increase with decreasing water activity (0.33...

  18. Comparing cellular performance of Yarrowia lipolytica during growth on glucose and glycerol in submerged cultivations

    DEFF Research Database (Denmark)

    Workman, Mhairi; Holt, Philippe; Thykær, Jette

    2013-01-01

    of applications for this yeast, relatively few studies have focused on uptake and metabolism of carbon sources, and the metabolic basis for carbon flow to the different products. The focus of this work was quantification of the cellular performance of Y. lipolytica during growth on glycerol, glucose or a mixture....... Growth on glycerol proceeded at approximately 0.30 h-1, and the substrate uptake rate was 0.02 mol L-1 h-1 regardless of the starting glycerol concentration (10, 20 or 45 g L-1). Utilisation of glycerol was accompanied by higher oxygen uptake rates compared to glucose growth, indicating import...... of glycerol occurred initially via phosphorylation of glycerol into glycerol-3-phosphate. Based on these results it could be speculated that once oxygen limitation was reached, additional production of NADH created imbalance in the cofactor pools and the polyol formation observed could be a result of cofactor...

  19. 3-Hydroxybutyrate regulates energy metabolism and induces BDNF expression in cerebral cortical neurons

    DEFF Research Database (Denmark)

    Marosi, Krisztina; Kim, Sang Woo; Moehl, Keelin

    2016-01-01

    During fasting and vigorous exercise, a shift of brain cell energy substrate utilization from glucose to the ketone 3-hydroxybutyrate (3OHB) occurs. Studies have shown that 3OHB can protect neurons against excitotoxicity and oxidative stress, but the underlying mechanisms remain unclear. Neurons ...

  20. Propionic acid fermentation of glycerol and glucose by Propionibacterium acidipropionici and Propionibacterium freudenreichii ssp. shermanii.

    Science.gov (United States)

    Himmi, E H; Bories, A; Boussaid, A; Hassani, L

    2000-04-01

    A comparative study was carried out in anaerobic batch cultures on 20 g/l of either glycerol or glucose using two propionibacteria strains, Propionibacterium acidipropionici and Propionibacterium freudenreichii ssp. shermanii. In all cases, fermentation end-products were the same and consisted of propionic acid as the major product, acetic acid as the main by-product and two minor metabolites, n-propanol and succinic acid. Evidence was provided that greater production of propionic acid by propionibacteria was obtained with glycerol as carbon and energy sources. P. acidipropionici showed higher efficiency in glycerol conversion to propionic acid with a faster substrate consumption (0.64 g l(-1) h(-1)) and a higher propionic acid production (0.42 g l(-1) h(-1) and 0.79 mol/mol). The almost exclusive production of propionic acid from glycerol by this bacterium suggested an homopropionic tendency of this fermentation. Acetic acid final concentration was two times lower on glycerol (2 g/l) than on glucose (4 g/l) for both micro-organisms. P. freudenreichii ssp. shermanii exhibited a glycerol fermentation pattern typical of non-associated glycerol-consumption-product formation. This could indicate a particular metabolism for P. freudenreichii ssp. shermanii oriented towards the production of other specific components. These results tend to show that glycerol could be an excellent alternative to conventional carbon sources such as carbohydrates for propionic acid production.

  1. The direct effect of incretin hormones on glucose and glycerol metabolism and hemodynamics

    DEFF Research Database (Denmark)

    Karstoft, Kristian; P. Mortensen, Stefan; H. Knudsen, Sine

    2015-01-01

    The objective of this study was to assess the insulin-independent effects of incretin hormones on glucose and glycerol metabolism and hemodynamics under eu- and hyperglycemic conditions. Young, healthy males (n=10) underwent three trials in a randomized, controlled, cross-over study. Each trial...... consisted of a 2-stage (eu- and hyperglycemia) pancreatic clamp (using somatostatin to prevent endogenous insulin secretion). Glucose and lipid metabolism were measured via infusion of stable glucose and glycerol isotopic tracers. Hemodynamic variables (femoral, brachial and common carotid artery blood flow...... or glycerol kinetics were seen during euglycemia, whereas hyperglycemia resulted in increased GIR and glucose rate of disappearance (Rd) during GLP-1 compared to CON and GIP (P

  2. Engineering Yarrowia lipolytica for poly-3-hydroxybutyrate production.

    Science.gov (United States)

    Li, Zheng-Jun; Qiao, Kangjian; Liu, Nian; Stephanopoulos, Gregory

    2017-05-01

    Strains of Yarrowia lipolytica were engineered to express the poly-3-hydroxybutyrate (PHB) biosynthetic pathway. The genes for β-ketothiolase, NADPH-dependent acetoacetyl-CoA reductase, and PHB synthase were cloned and inserted into the chromosome of Y. lipolytica. In shake flasks, the engineered strain accumulated PHB to 1.50 and 3.84% of cell dry weight in complex medium supplemented with glucose and acetate as carbon source, respectively. In fed-batch fermentation using acetate as sole carbon source, 7.35 g/l PHB (10.2% of cell dry weight) was produced. Selection of Y. lipolytica as host for PHB synthesis was motivated by the fact that this organism is a good lipids producer, which suggests robust acetyl-CoA supply also the precursor of the PHB pathway. Acetic acid could be supplied by gas fermentation, anaerobic digestion, and other low-cost supply route.

  3. Production of (R)-3-hydroxybutyric acid by Arxula adeninivorans.

    Science.gov (United States)

    Biernacki, Mateusz; Riechen, Jan; Hähnel, Urs; Roick, Thomas; Baronian, Kim; Bode, Rüdiger; Kunze, Gotthard

    2017-12-01

    (R)-3-hydroxybutyric acid can be used in industrial and health applications. The synthesis pathway comprises two enzymes, β-ketothiolase and acetoacetyl-CoA reductase which convert cytoplasmic acetyl-CoA to (R)-3-hydroxybutyric acid [(R)-3-HB] which is released into the culture medium. In the present study we used the non-conventional yeast, Arxula adeninivorans, for the synthesis enantiopure (R)-3-HB. To establish optimal production, we investigated three different endogenous yeast thiolases (Akat1p, Akat2p, Akat4p) and three bacterial thiolases (atoBp, thlp, phaAp) in combination with an enantiospecific reductase (phaBp) from Cupriavidus necator H16 and endogenous yeast reductases (Atpk2p, Afox2p). We found that Arxula is able to release (R)-3-HB used an existing secretion system negating the need to engineer membrane transport. Overexpression of thl and phaB genes in organisms cultured in a shaking flask resulted in 4.84 g L -1 (R)-3-HB, at a rate of 0.023 g L -1  h -1 over 214 h. Fed-batch culturing with glucose as a carbon source did not improve the yield, but a similar level was reached with a shorter incubation period [3.78 g L -1 of (R)-3-HB at 89 h] and the rate of production was doubled to 0.043 g L -1  h -1 which is higher than any levels in yeast reported to date. The secreted (R)-3-HB was 99.9% pure. This is the first evidence of enantiopure (R)-3-HB synthesis using yeast as a production host and glucose as a carbon source.

  4. Propionic acid production in glycerol/glucose co-fermentation by Propionibacterium freudenreichii subsp. shermanii.

    Science.gov (United States)

    Wang, Zhongqiang; Yang, Shang-Tian

    2013-06-01

    Propionibacterium freudenreichii subsp. shermanii can ferment glucose and glycerol to propionic acid with acetic and succinic acids as two by-products. Propionic acid production from glucose was relatively fast (0.19 g/Lh) but gave low product yield (~0.39 g/g) and selectivity (P/A: ~2.6; P/S: ~4.8). In contrast, glycerol with a more reduced state gave a high propionic acid yield (~0.65 g/g) and selectivity (P/A: ~31; P/S: ~11) but low productivity (0.11 g/L h). On the other hand, co-fermentation of glycerol and glucose at an appropriate mass ratio gave both a high yield (0.54-0.65 g/g) and productivity (0.18-0.23 g/L h) with high product selectivity (P/A: ~14; P/S: ~10). The carbon flux distributions in the co-fermentation as affected by the ratio of glycerol/glucose were investigated. Finally, co-fermentation with cassava bagasse hydrolysate and crude glycerol in a fibrous-bed bioreactor was demonstrated, providing an efficient way for economic production of bio-based propionic acid. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. High hydrogen production from glycerol or glucose by electrohydrogenesis using microbial electrolysis cells

    KAUST Repository

    Selembo, Priscilla A.

    2009-07-01

    The use of glycerol for hydrogen gas production was examined via electrohydrogenesis using microbial electrolysis cells (MECs). A hydrogen yield of 3.9 mol-H2/mol was obtained using glycerol, which is higher than that possible by fermentation, at relatively high rates of 2.0 ± 0.4 m3/m3 d (Eap = 0.9 V). Under the same conditions, hydrogen was produced from glucose at a yield of 7.2 mol-H2/mol and a rate of 1.9 ± 0.3 m3/m3 d. Glycerol was completely removed within 6 h, with 56% of the electrons in intermediates (primarily 1,3-propanediol), with the balance converted to current, intracellular storage products or biomass. Glucose was removed within 5 h, but intermediates (mainly propionate) accounted for only 19% of the electrons. Hydrogen was also produced using the glycerol byproduct of biodiesel fuel production at a rate of 0.41 ± 0.1 m3/m3 d. These results demonstrate that electrohydrogenesis is an effective method for producing hydrogen from either pure glycerol or glycerol byproducts of biodiesel fuel production. © 2009 International Association for Hydrogen Energy.

  6. Peculiarities of glucose and glycerol metabolism in Nocardia vaccinii IMB B-7405

    Directory of Open Access Journals (Sweden)

    T. P. Pirog

    2015-04-01

    Full Text Available It has been established that in cells of Nocardia vaccinii IMB B-7405 (surfactant producer glucose catabolism is performed through pentose phosphate cycle as well as through gluconate (activi­ty of NAD+-dependent glucose-6- phosphate dehydrogenase and FAD+-dependent glucose dehydrogenase 835 ± 41 and 698 ± 35 nmol∙min-1∙mg-1 of protein respectively. 6-Phosphogluconate formed in the gluconokinase reaction is involved in the pentose phosphate cycle (activity of constitutive NADP+-dependent 6-phosphogluconate dehydrogenase 357 ± 17 nmol∙min-1∙mg-1 of protein. Glyce­rol catabolism to dihydroxyacetonephosphate (the intermediate of glycolysis may be performed in two ways: through glycerol-3-phosphate (glycerol kinase activity 244 ± 12 nmol∙min-1∙mg-1 of protein and through dihydroxyacetone. Replenishment of the C4-dicarboxylic acids pool in N. vaccinii IMV B-7405 grown on glucose and glycerol occurs in the phosphoenolpyruvate(PEPcarboxylase reaction (714–803 nmol∙min-1∙mg-1 of protein. 2-Oxoglutara­te was involved in tricarboxylic acid cycle by alternate pathway with the participation of 2-oxoglutarate synthase. The observed activity of both key enzymes of gluconeogenesis (PEP- carboxykinase and PEP-synthase, trehalose phosphate synthase and NADP+-dependent glutamate dehydrogenase confirmed the ability of IMV B-7405 strain to the synthesis of surface active glyco- and aminolipids, respectively.

  7. Poly(3-hydroxybutyrate and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate: Structure, Property, and Fiber

    Directory of Open Access Journals (Sweden)

    Qingsheng Liu

    2014-01-01

    Full Text Available Poly(3-hydroxybutyrate [P(3HB] and poly(3-hydroxybutyrate-co-3-hydroxyvalerate [P(3HB-co-3HV] are produced by various microorganisms as an intracellular carbon and energy reserve from agricultural feedstocks such as sugars and plant oils under unbalanced growth conditions. P(3HB and P(3HB-co-3HV have attracted the attention of academia and industry because of its biodegradability, biocompatibility, thermoplasticity, and plastic-like properties. This review first introduced the isodimorphism, spherulites, and molecular interaction of P(3HB and P(3HB-co-3HV. In addition, the effects of 3HV content on the melting temperature and crystallization rate were discussed. Then the drawbacks of P(3HB and P(3HB-co-3HV including brittleness, narrow melt processing window, low crystallization rate, slow biodegradation rate in body, and so on were summarized. At last, the preparation, structure, and properties of P(3HB and P(3HB-co-3HV fiber were introduced.

  8. MicroRNA-451 Negatively Regulates Hepatic Glucose Production and Glucose Homeostasis by Targeting Glycerol Kinase-Mediated Gluconeogenesis.

    Science.gov (United States)

    Zhuo, Shu; Yang, Mengmei; Zhao, Yanan; Chen, Xiaofang; Zhang, Feifei; Li, Na; Yao, Pengle; Zhu, Tengfei; Mei, Hong; Wang, Shanshan; Li, Yu; Chen, Shiting; Le, Yingying

    2016-11-01

    MicroRNAs (miRNAs) are a new class of regulatory molecules implicated in type 2 diabetes, which is characterized by insulin resistance and hepatic glucose overproduction. We show that miRNA-451 (miR-451) is elevated in the liver tissues of dietary and genetic mouse models of diabetes. Through an adenovirus-mediated gain- and loss-of-function study, we found that miR-451 negatively regulates hepatic gluconeogenesis and blood glucose levels in normal mice and identified glycerol kinase (Gyk) as a direct target of miR-451. We demonstrate that miR-451 and Gyk regulate hepatic glucose production, the glycerol gluconeogenesis axis, and the AKT-FOXO1-PEPCK/G6Pase pathway in an opposite manner; Gyk could reverse the effect of miR-451 on hepatic gluconeogenesis and AKT-FOXO1-PEPCK/G6Pase pathway. Moreover, overexpression of miR-451 or knockdown of Gyk in diabetic mice significantly inhibited hepatic gluconeogenesis, alleviated hyperglycemia, and improved glucose tolerance. Further studies showed that miR-451 is upregulated by glucose and insulin in hepatocytes; the elevation of hepatic miR-451 in diabetic mice may contribute to inhibiting Gyk expression. This study provides the first evidence that miR-451 and Gyk regulate the AKT-FOXO1-PEPCK/G6Pase pathway and play critical roles in hepatic gluconeogenesis and glucose homeostasis and identifies miR-451 and Gyk as potential therapeutic targets against hyperglycemia in diabetes. © 2016 by the American Diabetes Association.

  9. Comparison of glucose and glycerol as carbon sources for ε-poly-L-lysine production by Streptomyces sp. M-Z18.

    Science.gov (United States)

    Chen, Xu-Sheng; Mao, Zhong-Gui

    2013-05-01

    Glucose is widely used in the production of ε-poly-L-lysine (ε-PL); however, glycerol is an emerging carbon source for ε-PL production in recent years. Glycerol is superior to glucose for ε-PL production according to batch and fed-batch fermentations by Streptomyces sp. M-Z18 in this study. To elaborate this difference, physiological metabolism of Streptomyces sp. M-Z18 on glycerol has compared with glucose during batch fermentation. The activities of key enzymes showed that aspartate kinase (ASPK) and ε-PL synthetase (Pls) in glycerol medium was higher than those in glucose, and especially the activity of Pls could enhance by 2.3- and 3.6-fold at 24 and 36 h, respectively. Moreover, metabolism flux analysis demonstrated that a 25 % higher fluxes derived from glycerol are directed into ε-PL synthesis than glucose. As a result, the mechanism of glycerol better than glucose is determined: the activities of ASPK and Pls in glycerol higher than those in glucose, and result in carbon fluxes directed into ε-PL synthesis increased. This study offers a reference to substitute glycerol for conventional glucose as carbon source for ε-PL production.

  10. Effects of carbon dioxide on cell growth and propionic acid production from glycerol and glucose by Propionibacterium acidipropionici.

    Science.gov (United States)

    Zhang, An; Sun, Jianxin; Wang, Zhongqiang; Yang, Shang-Tian; Zhou, Haiying

    2015-01-01

    The effects of CO2 on propionic acid production and cell growth in glycerol or glucose fermentation were investigated in this study. In glycerol fermentation, the volumetric productivity of propionic acid with CO2 supplementation reached 2.94g/L/day, compared to 1.56g/L/day without CO2. The cell growth using glycerol was also significantly enhanced with CO2. In addition, the yield and productivity of succinate, the main intermediate in Wood-Werkman cycle, increased 81% and 280%, respectively; consistent with the increased activities of pyruvate carboxylase and propionyl CoA transferase, two key enzymes in the Wood-Werkman cycle. However, in glucose fermentation CO2 had minimal effect on propionic acid production and cell growth. The carbon flux distributions using glycerol or glucose were also analyzed using a stoichiometric metabolic model. The calculated maintenance coefficient (mATP) increased 100%, which may explain the increase in the productivity of propionic acid in glycerol fermentation with CO2 supplement. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Glycerol Production from Glucose and Fructose by 3T3-L1 Cells: A Mechanism of Adipocyte Defense from Excess Substrate.

    Directory of Open Access Journals (Sweden)

    María del Mar Romero

    Full Text Available Cultured adipocytes (3T3-L1 produce large amounts of 3C fragments; largely lactate, depending on medium glucose levels. Increased glycolysis has been observed also in vivo in different sites of rat white adipose tissue. We investigated whether fructose can substitute glucose as source of lactate, and, especially whether the glycerol released to the medium was of lipolytic or glycolytic origin. Fructose conversion to lactate and glycerol was lower than that of glucose. The fast exhaustion of medium glucose was unrelated to significant changes in lipid storage. Fructose inhibited to a higher degree than glucose the expression of lipogenic enzymes. When both hexoses were present, the effects of fructose on gene expression prevailed over those of glucose. Adipocytes expressed fructokinase, but not aldolase b. Substantive release of glycerol accompanied lactate when fructose was the substrate. The mass of cell triacylglycerol (and its lack of change could not justify the comparatively higher amount of glycerol released. Consequently, most of this glycerol should be derived from the glycolytic pathway, since its lipolytic origin could not be (quantitatively sustained. Proportionally (with respect to lactate plus glycerol, more glycerol was produced from fructose than from glucose, which suggests that part of fructose was catabolized by the alternate (hepatic fructose pathway. Earlier described adipose glycerophophatase activity may help explain the glycolytic origin of most of the glycerol. However, no gene is known for this enzyme in mammals, which suggests that this function may be carried out by one of the known phosphatases in the tissue. Break up of glycerol-3P to yield glycerol, may be a limiting factor for the synthesis of triacylglycerols through control of glycerol-3P availability. A phosphatase pathway such as that described may have a potential regulatory function, and explain the production of glycerol by adipocytes in the absence of

  12. [From waste to treasure: turning activated sludge into bioplastic poly-3-hydroxybutyrate].

    Science.gov (United States)

    Chen, Jia'ni

    2017-12-25

    Large quantity of activated sludge is generated from wastewater treatment but without yet an appropriate deposition. High temperature can lyse the activate sludge so that nitrogen and phosphorus containing nutrients are released. Halomonas CJN was found to grow on the heat lysed activated sludge and glucose for production of bioplastic poly-3-hydroxybutyrate (PHB) in the absence of yeast extract, nitrogen and phosphorus sources as well as trace elements. This reduces the PHB production cost significantly. Furthermore, acetic acid formed from anaerobic fermentation of heat lysed activated sludge can be used to replace glucose for cell growth but not much for PHB production. After construction of an additional PHB synthesis pathway in Halomonas CJN, we can produce PHB entirely from heat lysed activated sludge, reducing production cost of PHB roughly from ¥ 30 000 Yuan/ton to ¥ 20 000 Yuan/ton, thus turning waste activated sludge to valuable raw material resource.

  13. In vivo effect of the D-(-) isomer or natural form of 3-hydroxybutyrate on initial release of lactate dehydrogenase from the acutely ischaemic myocardium.

    Science.gov (United States)

    Lammerant, J; Huynh-Thu, T; Kolanowski, J

    1986-07-01

    D-(-)-3-hydroxybutyrate, the isomer found in the circulation and in the urine of diabetic patients, generally is believed to be the physiologically important form of 3-hydroxybutyrate [10]. Little is known concerning the effects of an elevated plasma level of the D-(-) isomer of 3-hydroxybutyrate upon the acutely ischaemic heart. Using anaesthetized intact dogs with a balloon catheter inserted into the proximal part of the left anterior descending coronary artery (LAD), we have recently demonstrated that a 1 mM ketonaemia induced with the arginine salt of D-(-)-3-hydroxybutyric acid reduces the uptake of non-esterified fatty acids (NEFA) in the myocardial area distal to the inflated balloon [4]. The question arises as to whether the concomitant increase in ketone uptake in this area could be detrimental to the acutely ischaemic myocardium. Indeed, a previous study on isolated coronary ligated hearts from normal rats has shown that the rate of release of lactate dehydrogenase (LDH) during the first 90 min of ischaemia can be enhanced by replacing glucose (11 mM) in the perfusion fluid with either albumin-bound palmitate (0.9 mM) or sodium DL-3-hydroxybutyrate (10 mM) as the sole energy substrate [11]. This would suggest that the ketone might be as deleterious as its metabolic precursors for membrane integrity in the acutely ischaemic myocardium. In the present report, we examine the effect of arginine D-(-)-3-hydroxybutyrate on LDH release from ischaemic myocardium in our in vivo preparation. The dogs were treated with lidocaine in order to minimize the frequency and, hence, the adverse metabolic effects of ectopic beats.(ABSTRACT TRUNCATED AT 250 WORDS)

  14. Production of green biodegradable plastics of poly(3-hydroxybutyrate) from renewable resources of agricultural residues.

    Science.gov (United States)

    Dahman, Yaser; Ugwu, Charles U

    2014-08-01

    This work describes potential opportunities for utilization of agro-industrial residues to produce green biodegradable plastics of poly(3-hydroxybutyrate) (PHB). Wheat straws were examined with good efficacy of carbon substrates using Cupriavidus necator. Production was examined in separate hydrolysis and fermentation (SHF) in the presence and absence of WS hydrolysis enzymes, and in simultaneous saccharification and fermentation (SSF) with enzymes. Results showed that production of PHB in SSF was more efficient in terms of viable cell count, cell dry weight, and PHB production and yield compared to those of SHF and glucose-control cultures. While glucose control experiment produced 4.6 g/L PHB; SSF produced 10.0 g/L compared to 7.1 g/L in SHF when utilizing enzymes during WS hydrolysis. Results showed that most of sugars produced during the hydrolysis were consumed in SHF (~98 %) compared to 89.2 % in SSF. Results also demonstrated that a combination of glucose and xylose can compensate for the excess carbon required for enhancing PHB production by C. necator. However, higher concentration of sugars at the beginning of fermentation in SHF can lead to cell inhibition and consequently catabolite repressions. Accordingly, results demonstrated that the gradual release of sugars in SSF enhanced PHB production. Moreover, the presence of sugars other than glucose and xylose can eliminate PHB degradation in medium of low carbon substrate concentrations in SSF.

  15. Thermal stability of poly(3-hydroxybutyrate)/vegetable fiber composites

    Science.gov (United States)

    Cipriano, Pâmela Bento; de Sá, Mayelli Dantas; Andrade, André L. Simões; de Carvalho, Laura Hecker; Canedo, Eduardo Luis

    2015-05-01

    The present work deals with the thermal stability during and after processing of composites of poly(3-hydroxybutyrate) (PHB) - a fully biodegradable semi-crystalline thermoplastic obtained from renewable resources through low-impact biotechnological process, biocompatible and non-toxic - and vegetable fiber from the fruit (coconut) of babassu palm tree. PHB/babassu composites with 0, 5, 10 and 20% w/w load were prepared in a laboratory internal mixer. Two fractions of the mesocarp of babassu with different particle sizes were compounded with PHB and test specimens molded by compression. The effect of loading level and processing conditions on torque, temperature and mechanical energy dissipation were studied using a new engineering model. It was found that PHB degrades during processing at temperatures slightly above the melting point. To minimize thermal degradation stabilizer and chain extender additives were incorporated, with mixed results. These findings were confirmed by the dependence of the melt flow rate on the processing temperature.

  16. Thermoplastic starch and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) bionanocomposites before and after prolonged storage

    International Nuclear Information System (INIS)

    Magalhaes, N.F.; Dahmouche, K.; Andrade, C.T.

    2012-01-01

    Full text: Glycerol-plasticized cornstarch and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) were melt-mixed at a constant 70:30 (wt/wt) ratio. One-step extrusion processing were performed in the presence of a commercial organically-modified clay. The effect of increasing clay contents on the morphologies and physical properties of the blends was investigated after processing, and compared to the neat blend, by scanning electron microscopy (SEM), X-ray diffraction (XRD) and dynamic mechanical analysis (DMA). The results indicated that increasing clay contents promoted improvements in the compatibility between the components and allowed to better understand the role of clay in compatibilization mechanism. After aging for 12 months, the blends were characterized by SEM, XRD and Small-Angle X-ray Scattering (SAXS). As revealed by all techniques, the reduced size of the PHBV dispersed phase and the decreased crystallinity of both phases promoted by clay particles were maintained, although some prejudicial effect of aging was noticed. Nevertheless, SAXS results unambiguously proved the presence of both exfoliated lamellae and a small number of clay tactoids in the aged bionanocomposites. (author)

  17. Evaluation of 3-hydroxybutyrate as an enzyme-protective agent against heating and oxidative damage and its potential role in stress response of poly(3-hydroxybutyrate) accumulating cells

    Czech Academy of Sciences Publication Activity Database

    Obruča, S.; Sedláček, P.; Mravec, F.; Samek, Ota; Márová, I.

    2016-01-01

    Roč. 100, č. 3 (2016), s. 1365-1376 ISSN 0175-7598 R&D Projects: GA MŠk(CZ) LO1212; GA ČR(CZ) GA15-20645S Institutional support: RVO:68081731 Keywords : poly(3-hydroxybutyrate) * 3-Hydroxybutyrate * PHB cycle * chemical chaperone * compatible solutes Subject RIV: BH - Optics, Masers, Lasers Impact factor: 3.420, year: 2016

  18. Effect of Glycerol and Glucose on the Enhancement of Biomass, Lipid and Soluble Carbohydrate Production by Chlorella vulgaris in Mixotrophic Culture

    Directory of Open Access Journals (Sweden)

    Hong Yang

    2013-01-01

    Full Text Available Biodiesel-derived glycerol is a promising substrate for mixotrophic cultivation of oleaginous microalgae, which can also reduce the cost of microalgal biodiesel. The objective of this study is to investigate the potential of using glycerol and glucose as a complex carbon substrate to produce microalgal biomass and biochemical components, such as photosynthetic pigments, lipids, soluble carbohydrates and proteins by Chlorella vulgaris. The results show that C. vulgaris can utilize glycerol as a sole carbon substrate, but its effect is inferior to that of the mixture of glycerol and glucose. The effect of glycerol and glucose could enhance the algal cell growth rate, biomass content and volumetric productivity, and overcome the lower biomass production on glycerol as the sole organic carbon source in mixotrophic culture medium. The utilization of complex organic carbon substrate can stimulate the biosynthesis of lipids and soluble carbohydrates as the raw materials for biodiesel and bioethanol production, and reduce the anabolism of photosynthetic pigments and proteins. This study provides a promising niche for reducing the overall cost of biodiesel and bioethanol production from microalgae as it investigates the by-products of algal biodiesel production and algal cell hydrolysis as possible raw materials (lipids and carbohydrates and organic carbon substrates (soluble carbohydrates and glycerol for mixotrophic cultivation of microalgae.

  19. Effects of replacing lactose from milk replacer by glucose, fructose, or glycerol on energy partitioning in veal calves.

    Science.gov (United States)

    Gilbert, M S; Pantophlet, A J; van den Borne, J J G C; Hendriks, W H; Schols, H A; Gerrits, W J J

    2016-02-01

    Calf milk replacers contain 40 to 50% lactose. Fluctuating dairy prices are a major economic incentive to replace lactose from milk replacers by alternative energy sources. Our objective was, therefore, to determine the effects of replacement of lactose with glucose, fructose, or glycerol on energy and protein metabolism in veal calves. Forty male Holstein-Friesian calves (114±2.4 kg) were fed milk replacer containing 46% lactose (CON) or 31% lactose and 15% of glucose (GLUC), fructose (FRUC), or glycerol (GLYC). Solid feed was provided at 10 g of dry matter (DM)/kg of metabolic body weight (BW(0.75)) per day. After an adaptation of 48 d, individual calves were harnessed, placed in metabolic cages, and housed in pairs in respiration chambers. Apparent total-tract disappearance of DM, energy, and N and complete energy and N balances were measured. The GLUC, FRUC, and GLYC calves received a single dose of 1.5 g of [U-(13)C]glucose, [U-(13)C]fructose, or [U-(13)C]glycerol, respectively, with their milk replacer at 0630 h and exhaled (13)CO2 and (13)C excretion with feces was measured. Apparent total-tract disappearance was decreased by 2.2% for DM, 3.2% for energy, and 4.2% for N in FRUC compared with CON calves. Energy and N retention did not differ between treatments, and averaged 299±16 kJ/kg of BW(0.75) per day and 0.79±0.04 g/kg of BW(0.75) per day, respectively, although FRUC calves retained numerically less N (13%) than other calves. Recovery of (13)C isotopes as (13)CO2 did not differ between treatments and averaged 72±1.6%. The time at which the maximum rate of (13)CO2 production was reached was more than 3 h delayed for FRUC calves, which may be explained by a conversion of fructose into other substrates before being oxidized. Recovery of (13)C in feces was greater for FRUC calves (7.7±0.59%) than for GLUC (1.0±0.27%) and GLYC calves (0.5±0.04%), indicating incomplete absorption of fructose from the small intestine resulting in fructose excretion or

  20. Coutilization of glucose and glycerol enhances the production of aromatic compounds in an Escherichia coli strain lacking the phosphoenolpyruvate: carbohydrate phosphotransferase system

    Directory of Open Access Journals (Sweden)

    Bolívar Francisco G

    2008-01-01

    Full Text Available Abstract Background Escherichia coli strains lacking the phosphoenolpyruvate: carbohydrate phosphotransferase system (PTS are capable of coutilizing glucose and other carbon sources due to the absence of catabolite repression by glucose. In these strains, the lack of this important regulatory and transport system allows the coexistence of glycolytic and gluconeogenic pathways. Strains lacking PTS have been constructed with the goal of canalizing part of the phosphoenolpyruvate (PEP not consumed in glucose transport to the aromatic pathway. The deletion of the ptsHIcrr operon inactivates PTS causing poor growth on this sugar; nonetheless, fast growing mutants on glucose have been isolated (PB12 strain. However, there are no reported studies concerning the growth potential of a PTS- strain in mixtures of different carbon sources to enhance the production of aromatics compounds. Results PB12 strain is capable of coutilizing mixtures of glucose-arabinose, glucose-gluconate and glucose-glycerol. This capacity increases its specific growth rate (μ given that this strain metabolizes more moles of carbon source per unit time. The presence of plasmids pRW300aroGfbr and pCLtktA reduces the μ of strain PB12 in all mixtures of carbon sources, but enhances the productivity and yield of aromatic compounds, especially in the glucose-glycerol mixture, as compared to glucose or glycerol cultures. No acetate was detected in the glycerol and the glucose-glycerol batch fermentations. Conclusion Due to the lack of catabolite repression, PB12 strain carrying multicopy plasmids containing tktA and aroGfbr genes is capable of coutilizing glucose and other carbon sources; this capacity, reduces its μ but increases the production of aromatic compounds.

  1. Taxonomic characterization and metabolic analysis of the Halomonas sp. KM-1, a highly bioplastic poly(3-hydroxybutyrate)-producing bacterium.

    Science.gov (United States)

    Kawata, Yoshikazu; Shi, Lian-Hua; Kawasaki, Kazunori; Shigeri, Yasushi

    2012-04-01

    In a brief previous report, the gram-negative moderately halophilic bacterium, Halomonas sp. KM-1, that was isolated in our laboratory was shown to produce the bioplastic, poly(3-hydroxybutyrate) (PHB), using biodiesel waste glycerol (Kawata and Aiba, Biosci. Biotechnol. Biochem., 74, 175-177, 2010). Here, we further characterized this KM-1 strain and compared it to other Halomonas strains. Strain KM-1 was subjected to a polyphasic taxonomic study. Strain KM-1 was rod-shaped and formed colonies on a plate that were cream-beige in color, smooth, opaque, and circular with entire edges. KM-1 grew under environmental conditions of 0.1%-10% (w/v) NaCl, pH 6.5-10.5 and at temperatures between 10°C and 45°C. The G+C content of strain KM-1 was 63.9 mol%. Of the 16 Halomonas strains examined in this study, the strain KM-1 exhibited the highest production of PHB (63.6%, w/v) in SOT medium supplemented with 10% glycerol, 10.0 g/L sodium nitrate and 2.0 g/L dipotassium hydrogen phosphate. The intracellular structures within which PHB accumulated had the appearance of intracellular granules with a diameter of approximately 0.5 μm, as assessed by electron microscopy. The intra- and extra-cellular metabolites of strain KM-1 were analyzed by capillary electrophoresis mass spectrometry. In spite of the high amount of PHB stored intra-cellularly, as possible precursors for PHB only a small quantity of 3-hydroxybutyric acid and acetyl CoA, and no quantity of 3-hydroxybutyl CoA, acetoacetyl CoA and acetoacetate were detected either intra- or extra-cellularly, suggesting highly efficient conversion of these precursors to PHB. Copyright © 2011 The Society for Biotechnology, Japan. All rights reserved.

  2. Glycolysis of poly(3-hydroxybutyrate) via enzyme catalysis

    International Nuclear Information System (INIS)

    Paula, Everton Luiz de; Campos, Tiago Ferreira; Mano, Valdir

    2014-01-01

    Poly(3-hydroxybutyrate), PHB, is a polymer with broad potential applications because of its biodegradability and biocompatibility. However, its high crystallinity is a limiting factor for many applications. To overcome this drawback, one strategy currently employed involves the reduction of the molecular weight of PHB with the concomitant formation of end-functionalized chains, such as those obtained via glycolysis. The glycolysis of PHB can be catalyzed by acid, base, or organometallic compounds. However, to our knowledge, there are no reports regarding PHB glycolysis catalyzed enzymatically. Among the major types of enzymes used in biocatalysis, the lipases stand out because they have the ability to catalyze reactions in both aqueous and organic media. Thus, in this study, we performed the enzymatic glycolysis of PHB using the lipase Amano PS (Pseudomonas cepacia) with ethane-1,2-diol (ethylene glycol) as the functionalizing agent. The results indicated that the glycolysis was successful and afforded hydroxyl-terminated oligomeric PHB polyols. Nuclear magnetic resonance spectra of the products showed characteristic signals for the terminal hydroxyl groups of the polyols, while thermogravimetric and differential scanning calorimetry analyses confirmed an increase in the thermal stability and a decrease in the crystallinity of the polyols compared with the starting PHB polymer, which were both attributed to the reduction in the molecular weight due to glycolysis. (author)

  3. Thermal properties of poly(3-hydroxybutyrate)/vegetable fiber composites

    Science.gov (United States)

    Vitorino, Maria B. C.; Reul, Lízzia T. A.; Carvalho, Laura H.; Canedo, Eduardo L.

    2015-05-01

    The present work studies the thermal properties of composites of poly(3-hydroxybutyrate) (PHB) - a fully biodegradable semi-crystalline thermo-plastic obtained from renewable resources through low-impact biotechno-logical process, biocompatible and non-toxic - and vegetable fiber from the fruit (coconut) of babassu palm tree. PHB is a highly crystalline resin and this characteristic leads to suboptimal properties in some cases. Consequently, thermal properties, in particular those associated with the crystallization of the matrix, are important to judge the suitability of the compounds for specific applications. PHB/babassu composites with 0-50% load were prepared in an internal mixer. Two different types of babassu fibers with two different particle size ranges were compounded with PHB and test specimens molded by compression. Melting and crystallization behavior were studied by differential scanning calorimetry (DSC) at heating/cooling rates between 2 and 30°C/min. Several parameters, including melting point, crystallization temperature, crystallinity, and rate of crystallization, were estimated as functions of load and heating/cooling rates. Results indicate that fibers do not affect the melting process, but facilitate crystallization from the melt. Crystallization temperatures are 30 to 40°C higher for the compounds compared with the neat resin. However, the amount of fiber added has little effect on crystallinity and the degree of crystallinity is hardly affected by the load. Fiber type and initial particle size do not have a significant effect on thermal properties.

  4. PPARa governs glycerol metabolism

    NARCIS (Netherlands)

    Patsouris, D.A.; Mandard, S.J.; Voshol, P.J.; Escher, P.; Tan, N.S.; Havekes, L.M.; Koenig, W.; März, W.; Müller, M.R.; Kersten, A.H.

    2004-01-01

    Glycerol, a product of adipose tissue lipolysis, is an important substrate for hepatic glucose synthesis. However, little is known about the regulation of hepatic glycerol metabolism. Here we show that several genes involved in the hepatic metabolism of glycerol, i.e., cytosolic and mitochondrial

  5. Electrocatalytic properties of nanomaterials synthesized from “Bromide Anion Exchange” method - Investigations of glucose and glycerol oxidation

    International Nuclear Information System (INIS)

    Holade, Yaovi; Servat, Karine; Napporn, Teko W.; Kokoh, K. Boniface

    2015-01-01

    Highlights: • Scrutiny of Bromide Anion Exchange (BAE) straightforward synthesis method. • Molar concentration of metal salt and bromide ion content control BAE method. • Enhanced kinetic of glucose electrooxidation on AuPd/C and AuPt/C. • Glycerate and glycolate are the main glycerol reaction products on Pd/C. - Abstract: In this work, different experimental parameters influencing the straightforward nanoparticles synthesis method, so-called Bromide Anion Exchange (BAE) were scrutinized. It was found that a bromide ion to metal(s) molar ratio of 1.5 gave the best electrochemical activity of the obtained catalysts toward the organics oxidation. The revisited BAE synthesis approach allows the preparation of highly active AuPt/C and AuPd/C nanomaterials. It has been highlighted that this method changes drastically the structure of AuPd nanostructures leading to alloyed system when Au atomic content is higher than 50%. These gold-based materials can be considered as advanced surfactant-free nanoparticles for anode electrodes design in abiotic or hybrid glucose biofuel cell. Furthermore, qualitative and quantitative analyses of glycerol conversion indicate that glycolate and glycerate are the main final products with selectivity higher than 40 and 30%, respectively

  6. Model of acetic acid-affected growth and poly(3-hydroxybutyrate) production by Cupriavidus necator DSM 545.

    Science.gov (United States)

    Marudkla, Jaruwan; Lee, Wen-Chien; Wannawilai, Siwaporn; Chisti, Yusuf; Sirisansaneeyakul, Sarote

    2018-02-20

    Acetic acid, a potential growth inhibitor, commonly occurs in lignocellulosic hydrolysates. The growth of Cupriavidus necator DSM 545 and production of poly(3-hydroxybutyrate) (PHB) by this bacterium in a glucose-based medium supplemented with various initial concentrations of acetic acid are reported. The bacterium could use both glucose and acetic acid to grow and produce PHB, but acetic acid inhibited growth once its initial concentration exceeded 0.5 g/L. As acetic acid is an unavoidable contaminant in hydrolysates used as sugar sources in commercial fermentations, a mathematical model was developed to describe its impact on growth and the production of PHB. The model was shown to satisfactorily apply to growth and PHB production data obtained in media made with acetic-acid-containing hydrolysates of Napier grass and oil palm trunk as carbon substrates. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Environmental biodegradation of haloarchaea-produced poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in activated sludge

    DEFF Research Database (Denmark)

    Liu, Xiao-Bin; Wu, Linping; Hou, Jing

    2016-01-01

    Novel poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) copolymers produced by haloarchaea are excellent candidate biomaterials. However, there is no report hitherto focusing on the biodegradation of PHBHV synthesized by haloarchaea. In this study, an environmental biodegradation of haloarchae...

  8. Production of Poly (3-Hydroxybutyric Acid) by Ralstonia eutropha in a Biocalorimeter and its Thermokinetic Studies.

    Science.gov (United States)

    Anusha, Subramanian Mohanakrishnan; Leelaram, Santharam; Surianarayanan, Mahadevan

    2016-07-01

    Bioplastic production from microbial sources is an emerging area which provides opportunities even to convert the wastes into bioplastics. Poly (3-hydroxybutyric acid), commonly called as PHB, is a bioplastic, which is stored as intracellular cytoplasmic inclusions in microorganisms. The objectives of this study are to calorimetrically monitor the PHB production and evaluate the thermokinetic data in a bioreaction calorimeter (BioRC1e). Thus, a well-known PHB-producing bacteria Ralstonia eutropha was selected for batch process in a bioreaction calorimeter. The metabolic heat generated was found to be correlated with the biomass, substrate consumption, oxygen uptake rate (OUR), carbon dioxide evolution rate (CER) and PHB production. The OUR pattern explained the oxidative metabolism of the strain R. eutropha. The heat yields due to biomass and glucose consumption during PHB production were found to be 12.56 and 13.56 kJ/g, respectively. The oxycalorific value obtained for the PHB production was 443.80 kJ/mol of O2. The concentration of PHB obtained in BioRC1e was 4.33 g/L with a production rate of 0.09 g/L/h. The chemical structure of the extracted PHB by R. eutropha was confirmed using fourier transform infrared spectroscopy (FT-IR) and (1)H and (13)C nuclear magnetic resonance (NMR) analysis.

  9. Biorefinery production of poly-3-hydroxybutyrate using waste office paper hydrolysate as feedstock for microbial fermentation.

    Science.gov (United States)

    Neelamegam, Annamalai; Al-Battashi, Huda; Al-Bahry, Saif; Nallusamy, Sivakumar

    2018-01-10

    Waste paper, a major fraction of municipal solid waste, has a potential to serve as renewable feedstock for the biorefineries of fuels, chemicals and materials due to rich in cellulose and abundant at low cost. This study evaluates the possibility of waste office paper (WOP) to serve as a potential feedstock for the biorefinery production of poly (3-hydroxybutyrate). In this study, the WOP was pretreated, enzymatically saccharified and the hydrolysate was used for PHB production. The hydrolysate mainly consists of glucose (22.70g/L) and xylose (1.78g/L) and the corresponding sugar yield was about 816mg/g. Ammonium sulphate and C/N ratio 20 were identified as most favorable for high yield of PHB. The batch fermentation of Cupriavidus necator using the pretreated WOP hydrolysate resulted in cell biomass, PHB production and PHB content of 7.74g/L, 4.45g/L and 57.52%, respectively. The volumetric productivity and yield achieved were 0.061g/L/h and 0.210g/g sugar, respectively. The results suggested that WOP could be a potential alternative feedstock for the biorefinery production of bioplastics. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Regulating the production of (R-3-hydroxybutyrate in Escherichia coli by N or P limitation

    Directory of Open Access Journals (Sweden)

    Mónica eGuevara-Martínez

    2015-08-01

    Full Text Available The chiral compound (R-3-hydroxybutyrate (3HB is naturally produced by many wild type organisms as the monomer for polyhydroxybutyrate (PHB. Both compounds are commercially valuable and co-polymeric polyhydroxyalkanoates have been used e.g. in medical applications for skin grafting and as components in pharmaceuticals.In this paper we investigate cultivation strategies for production of 3HB in the previously described E. coli strain AF1000 pJBGT3RX. This strain produces extracellular 3HB by expression of two genes from the PHB pathway of Halomonas boliviensis. H. boliviensis is a newly isolated halophile that forms PHB as a storage compound during carbon excess and simultaneous limitation of another nutrient like nitrogen and phosphorous. We hypothesize that a similar approach can be used to control the flux from acetyl-CoA to 3HB also in E. coli; decreasing the flux to biomass and favouring the pathway to the product. We employed ammonium- or phosphate-limited fed-batch processes for comparison of the productivity at different nutrient limitation or starvation conditions. The feed rate was shown to affect the rate of glucose consumption, respiration, 3HB and acetic acid production, although the proportions between them were more difficult to affect. The highest 3HB volumetric productivity, 1.5 g L-1 h-1, was seen for phosphate-limitation.

  11. Ketone body 3-hydroxybutyrate mimics calorie restriction via the Nrf2 activator, fumarate, in the retina.

    Science.gov (United States)

    Izuta, Yusuke; Imada, Toshihiro; Hisamura, Ryuji; Oonishi, Erina; Nakamura, Shigeru; Inagaki, Emi; Ito, Masataka; Soga, Tomoyoshi; Tsubota, Kazuo

    2018-02-01

    Calorie restriction (CR) being the most robust dietary intervention provides various health benefits. D-3-hydroxybutyrate (3HB), a major physiological ketone, has been proposed as an important endogenous molecule for CR. To investigate the role of 3HB in CR, we investigated potential shared mechanisms underlying increased retinal 3HB induced by CR and exogenously applied 3HB without CR to protect against ischemic retinal degeneration. The repeated elevation of retinal 3HB, with or without CR, suppressed retinal degeneration. Metabolomic analysis showed that the antioxidant pentose phosphate pathway and its limiting enzyme, glucose-6-phosphate dehydrogenase (G6PD), were concomitantly preserved. Importantly, the upregulation of nuclear factor erythroid 2 p45-related factor 2 (Nrf2), a regulator of G6PD, and elevation of the tricarboxylic acid cycle's Nrf2 activator, fumarate, were also shared. Together, our findings suggest that CR provides retinal antioxidative defense by 3HB through the antioxidant Nrf2 pathway via modification of a tricarboxylic acid cycle intermediate during 3HB metabolism. © 2017 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  12. Redox Balance in Lactobacillus reuteri DSM20016: Roles of Iron-Dependent Alcohol Dehydrogenases in Glucose/ Glycerol Metabolism.

    Science.gov (United States)

    Chen, Lu; Bromberger, Paul David; Nieuwenhuiys, Gavin; Hatti-Kaul, Rajni

    2016-01-01

    Lactobacillus reuteri, a heterofermentative bacterium, metabolizes glycerol via a Pdu (propanediol-utilization) pathway involving dehydration to 3-hydroxypropionaldehyde (3-HPA) followed by reduction to 1,3-propandiol (1,3-PDO) with concomitant generation of an oxidized cofactor, NAD+ that is utilized to maintain cofactor balance required for glucose metabolism and even for oxidation of 3-HPA by a Pdu oxidative branch to 3-hydroxypropionic acid (3-HP). The Pdu pathway is operative inside Pdu microcompartment that encapsulates different enzymes and cofactors involved in metabolizing glycerol or 1,2-propanediol, and protects the cells from the toxic effect of the aldehyde intermediate. Since L. reuteri excretes high amounts of 3-HPA outside the microcompartment, the organism is likely to have alternative alcohol dehydrogenase(s) in the cytoplasm for transformation of the aldehyde. In this study, diversity of alcohol dehydrogenases in Lactobacillus species was investigated with a focus on L. reuteri. Nine ADH enzymes were found in L. reuteri DSM20016, out of which 3 (PduQ, ADH6 and ADH7) belong to the group of iron-dependent enzymes that are known to transform aldehydes/ketones to alcohols. L. reuteri mutants were generated in which the three ADHs were deleted individually. The lagging growth phenotype of these deletion mutants revealed that limited NAD+/NADH recycling could be restricting their growth in the absence of ADHs. Notably, it was demonstrated that PduQ is more active in generating NAD+ during glycerol metabolism within the microcompartment by resting cells, while ADH7 functions to balance NAD+/NADH by converting 3-HPA to 1,3-PDO outside the microcompartment in the growing cells. Moreover, evaluation of ADH6 deletion mutant showed strong decrease in ethanol level, supporting the role of this bifuctional alcohol/aldehyde dehydrogenase in ethanol production. To the best of our knowledge, this is the first report revealing both internal and external recycling

  13. A Burkholderia sacchari cell factory: production of poly-3-hydroxybutyrate, xylitol and xylonic acid from xylose-rich sugar mixtures.

    Science.gov (United States)

    Raposo, Rodrigo S; de Almeida, M Catarina M D; de Oliveira, M da Conceição M A; da Fonseca, M Manuela; Cesário, M Teresa

    2017-01-25

    Efficient production of poly-3-hydroxybutyrate (P(3HB)) based on glucose-xylose mixtures simulating different types of lignocellulosic hydrolysate (LCH) was addressed using Burkholderia sacchari, a wild strain capable of metabolizing both sugars and producing P(3HB). Carbon catabolite repression was avoided by maintaining glucose concentration below 10g/L. Xylose concentrations above 30g/L were inhibitory for growth and production. In fed-batch cultivations, pulse size and feed addition rate were controlled in order to reach high productivities and efficient sugar consumptions. High xylose uptake and P(3HB) productivity were attained with glucose-rich mixtures (glucose/xylose ratio in the feed=1.5w/w) using high feeding rates, while with xylose-richer feeds (glucose/xylose=0.8w/w), a lower feeding rate is a robust strategy to avoid xylose build-up in the medium. Xylitol production was observed with xylose concentrations in the medium above 30-40g/L. With sugar mixtures featuring even lower glucose/xylose ratios, i.e. xylose-richer feeds (glucose/xylose=0.5), xylonic acid (a second byproduct) was produced. This is the first report of the ability of Burkholderia sacchari to produce both xylitol and xylonic acid. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Interfacial improvements in biocomposites based on poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) bioplastics reinforced and grafted with α-cellulose fibers

    Science.gov (United States)

    Liqing Wei; Nicole M. Stark; Armando G. McDonald

    2015-01-01

    In this study, α-cellulose fibers reinforced green biocomposites based on polyhydroxybutyrate (PHB) and the copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) were prepared and characterized. The α-cellulose fibers were isolated from at-risk intermountain lodgepole pine wood by successive removal of extractives, lignin and hemicellulose...

  15. Synthesis of poly(3-hydroxybutyrate using enzymes Azospirillum brasilense in vitro

    Directory of Open Access Journals (Sweden)

    Soheila Abbasi

    2017-06-01

    Full Text Available Introduction:Polyhydroxyalkaniates (PHAS are bacterial polymers that are formed as naturally occurring storage polyesters by a wide range of microorganisms usually under unbalanced growth conditions. Mechanical properties of PHAS make them suitable replacements for petrochemically produced bulk plastics (polyethylene, polypropylene etc., but in contrast to these commodity plastics PHA are completely degradable to carbon dioxide and water through natural microbiological mineralization. PHAS can be produced by biotechnological processes under controlled conditions. Polyhydroxybotyric acid (PHB was the first of thePHAS discovered and is the most abundant polyester found in bacteria. Materials and methods: First, a rich bacterial suspension prepared from poly(3-hydroxybutyrate, then the cells were broken down and ensure the absence of live cells.The cell free enzymes were added to M9 medium.Then the sample turbidity was measured at a wavelength of 600 nm and incubated at 30°C and centrifiuged at 120rpm. Next, the amount of PHB as well as solution turbidity were measured and compared with control. The physical and chemical analyzes of extracted PHB samples such as UV absorbtion, FTIR, HPLC and HNMR assesed and compared with standard sample. Results: In twelve days this experiment was conducted, from the third day, the amount of polyhydroxybutyrate was measurable and the highest polyhydroxybutyrate was gained on the tenth day. The level of PHB was constant. Moreover, the level of glucose was decreased gradually till the tenth day. By Physico-chemical analysis, production of polyhydroxybutyrate was approved. Discussion and conclusion: In this experiment, the reaction efficiency was 37.5 percent. Probably the rest of glucose could be changed to other intermediate compounds by other enzymes in the sample.Therefore, by purification of the enzyme, usage of specific substrate and optimization of conditions outside the cell could help the production of

  16. Redox Balance in Lactobacillus reuteri DSM20016: Roles of Iron-Dependent Alcohol Dehydrogenases in Glucose/ Glycerol Metabolism.

    Directory of Open Access Journals (Sweden)

    Lu Chen

    Full Text Available Lactobacillus reuteri, a heterofermentative bacterium, metabolizes glycerol via a Pdu (propanediol-utilization pathway involving dehydration to 3-hydroxypropionaldehyde (3-HPA followed by reduction to 1,3-propandiol (1,3-PDO with concomitant generation of an oxidized cofactor, NAD+ that is utilized to maintain cofactor balance required for glucose metabolism and even for oxidation of 3-HPA by a Pdu oxidative branch to 3-hydroxypropionic acid (3-HP. The Pdu pathway is operative inside Pdu microcompartment that encapsulates different enzymes and cofactors involved in metabolizing glycerol or 1,2-propanediol, and protects the cells from the toxic effect of the aldehyde intermediate. Since L. reuteri excretes high amounts of 3-HPA outside the microcompartment, the organism is likely to have alternative alcohol dehydrogenase(s in the cytoplasm for transformation of the aldehyde. In this study, diversity of alcohol dehydrogenases in Lactobacillus species was investigated with a focus on L. reuteri. Nine ADH enzymes were found in L. reuteri DSM20016, out of which 3 (PduQ, ADH6 and ADH7 belong to the group of iron-dependent enzymes that are known to transform aldehydes/ketones to alcohols. L. reuteri mutants were generated in which the three ADHs were deleted individually. The lagging growth phenotype of these deletion mutants revealed that limited NAD+/NADH recycling could be restricting their growth in the absence of ADHs. Notably, it was demonstrated that PduQ is more active in generating NAD+ during glycerol metabolism within the microcompartment by resting cells, while ADH7 functions to balance NAD+/NADH by converting 3-HPA to 1,3-PDO outside the microcompartment in the growing cells. Moreover, evaluation of ADH6 deletion mutant showed strong decrease in ethanol level, supporting the role of this bifuctional alcohol/aldehyde dehydrogenase in ethanol production. To the best of our knowledge, this is the first report revealing both internal and

  17. Gis1 and Rph1 regulate glycerol and acetate metabolism in glucose depleted yeast cells.

    Directory of Open Access Journals (Sweden)

    Jakub Orzechowski Westholm

    Full Text Available Aging in organisms as diverse as yeast, nematodes, and mammals is delayed by caloric restriction, an effect mediated by the nutrient sensing TOR, RAS/cAMP, and AKT/Sch9 pathways. The transcription factor Gis1 functions downstream of these pathways in extending the lifespan of nutrient restricted yeast cells, but the mechanisms involved are still poorly understood. We have used gene expression microarrays to study the targets of Gis1 and the related protein Rph1 in different growth phases. Our results show that Gis1 and Rph1 act both as repressors and activators, on overlapping sets of genes as well as on distinct targets. Interestingly, both the activities and the target specificities of Gis1 and Rph1 depend on the growth phase. Thus, both proteins are associated with repression during exponential growth, targeting genes with STRE or PDS motifs in their promoters. After the diauxic shift, both become involved in activation, with Gis1 acting primarily on genes with PDS motifs, and Rph1 on genes with STRE motifs. Significantly, Gis1 and Rph1 control a number of genes involved in acetate and glycerol formation, metabolites that have been implicated in aging. Furthermore, several genes involved in acetyl-CoA metabolism are downregulated by Gis1.

  18. The effect of gamma radiation on mechanical properties of biodegradable polymers poly(3-hydroxybutyrate and poly(3-hydroxybutyrate-co-3-hydroxyvalerate

    Directory of Open Access Journals (Sweden)

    Leticia Maria Oliveira

    2013-02-01

    Full Text Available Brazilian poly(3-hydroxybutyrate, P(3-HB, and its copolymer, poly (3-hydroxybutyrate-co-3-hydroxyvalerate, P(3-HB-co-3-HV were irradiated with gamma radiation (60Co at room temperature and in the presence of oxygen. The viscosity-average molar mass (Mv was analyzed by viscometry using an Ostwald-type capillary viscometer. Both polymers showed a decrease in molar mass with the increase in dose, reflecting that random main chain scissions occurred. The value G (scissions/100 eV of energy transferred to the system and the parameter α (scissions per original molecule were also determined. Mechanical properties decrease with the increase in dose, revealing that P(3-HB underwent significant changes, especially at doses higher than 50 kGy. Tensile at break and impact resistance properties were the most affected by radiation, while the elastic modulus remained virtually unaltered up to 100 kGy dose.

  19. Draft genome sequence of Halomonas sp. strain KM-1, a moderately halophilic bacterium that produces the bioplastic poly(3-hydroxybutyrate).

    Science.gov (United States)

    Kawata, Yoshikazu; Kawasaki, Kazunori; Shigeri, Yasushi

    2012-05-01

    We report the draft genome sequence of Halomonas sp. strain KM-1, which was isolated in Ikeda City, Osaka, Japan, and which produces the bioplastic poly(3-hydroxybutyrate). The total length of the assembled genome is 4,992,811 bp, and 4,220 coding sequences were predicted within the genome. Genes encoding proteins that are involved in the production and depolymerization of poly(3-hydroxybutyrate) were identified. The identification of these genes might be of use in the production of the bioplastic poly(3-hydroxybutyrate) and its monomer 3-hydroxybutyrate.

  20. Evolutionary engineering of a glycerol-3-phosphate dehydrogenase-negative, acetate-reducing Saccharomyces cerevisiae strain enables anaerobic growth at high glucose concentrations

    Science.gov (United States)

    Guadalupe-Medina, Víctor; Metz, Benjamin; Oud, Bart; van Der Graaf, Charlotte M; Mans, Robert; Pronk, Jack T; van Maris, Antonius J A

    2014-01-01

    Glycerol production by Saccharomyces cerevisiae, which is required for redox-cofactor balancing in anaerobic cultures, causes yield reduction in industrial bioethanol production. Recently, glycerol formation in anaerobic S. cerevisiae cultures was eliminated by expressing Escherichia coli (acetylating) acetaldehyde dehydrogenase (encoded by mhpF) and simultaneously deleting the GPD1 and GPD2 genes encoding glycerol-3-phosphate dehydrogenase, thus coupling NADH reoxidation to reduction of acetate to ethanol. Gpd– strains are, however, sensitive to high sugar concentrations, which complicates industrial implementation of this metabolic engineering concept. In this study, laboratory evolution was used to improve osmotolerance of a Gpd– mhpF-expressing S. cerevisiae strain. Serial batch cultivation at increasing osmotic pressure enabled isolation of an evolved strain that grew anaerobically at 1 M glucose, at a specific growth rate of 0.12 h−1. The evolved strain produced glycerol at low concentrations (0.64 ± 0.33 g l−1). However, these glycerol concentrations were below 10% of those observed with a Gpd+ reference strain. Consequently, the ethanol yield on sugar increased from 79% of the theoretical maximum in the reference strain to 92% for the evolved strains. Genetic analysis indicated that osmotolerance under aerobic conditions required a single dominant chromosomal mutation, and one further mutation in the plasmid-borne mhpF gene for anaerobic growth. PMID:24004455

  1. Evolutionary engineering of a glycerol-3-phosphate dehydrogenase-negative, acetate-reducing Saccharomyces cerevisiae strain enables anaerobic growth at high glucose concentrations.

    Science.gov (United States)

    Guadalupe-Medina, Víctor; Metz, Benjamin; Oud, Bart; van Der Graaf, Charlotte M; Mans, Robert; Pronk, Jack T; van Maris, Antonius J A

    2014-01-01

    Glycerol production by Saccharomyces cerevisiae, which is required for redox-cofactor balancing in anaerobic cultures, causes yield reduction in industrial bioethanol production. Recently, glycerol formation in anaerobic S. cerevisiae cultures was eliminated by expressing Escherichia coli (acetylating) acetaldehyde dehydrogenase (encoded by mhpF) and simultaneously deleting the GPD1 and GPD2 genes encoding glycerol-3-phosphate dehydrogenase, thus coupling NADH reoxidation to reduction of acetate to ethanol. Gpd⁻ strains are, however, sensitive to high sugar concentrations, which complicates industrial implementation of this metabolic engineering concept. In this study, laboratory evolution was used to improve osmotolerance of a Gpd⁻ mhpF-expressing S. cerevisiae strain. Serial batch cultivation at increasing osmotic pressure enabled isolation of an evolved strain that grew anaerobically at 1 M glucose, at a specific growth rate of 0.12 h⁻¹. The evolved strain produced glycerol at low concentrations (0.64 ± 0.33 g l⁻¹). However, these glycerol concentrations were below 10% of those observed with a Gpd⁺ reference strain. Consequently, the ethanol yield on sugar increased from 79% of the theoretical maximum in the reference strain to 92% for the evolved strains. Genetic analysis indicated that osmotolerance under aerobic conditions required a single dominant chromosomal mutation, and one further mutation in the plasmid-borne mhpF gene for anaerobic growth. © 2013 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  2. Methanol-induced chain termination in poly(3-hydroxybutyrate) biopolymers: molecular weight control

    Science.gov (United States)

    A systematic study was performed to demonstrate the impact of methanol (MeOH) on poly(3-hydroxybutyrate) (PHB) synthesis and molecular weight (MW) control. Glycerine (init. conc. = 1.0%; w/v), was used as the primary carbon source in batch-culture fermentations with varying concentrations (0 to 0.85...

  3. Waste cooking oil as substrate for biosynthesis of poly(3-hydroxybutyrate and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate: Turning waste into a value-added product

    Directory of Open Access Journals (Sweden)

    Yang, T. A.

    2013-01-01

    Full Text Available Aims: Improper disposal of domestic wastes, such as waste cooking oil (WCO, contributes to the deterioration of the environment and may lead to health problems. In this study, we evaluated the potential of plant-based WCO as a carbon source for the commercial biosynthesis of the bio-plastics, poly(3-hydroxybutyrate and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate. The consumption of WCO for this purpose would mitigate their pollution of the environment at the same time.Methodology and Results: WCO collected from several cafeterias in USM was tested as the carbon source for polyhydroxyalkanoates (PHA production. A selection of suitable nitrogen source was first conducted in order to obtain an acceptable number of dry cell weight (DCW and PHA content. Urea was found to be a suitable nitrogen source for the two bacterial strains used in our study, Cupriavidus necator H16 and its transformed mutant, C. necator PHB¯4 harboring the PHA synthase gene of Aeromonas caviae (PHB¯4/pBBREE32d13. With WCO as the sole carbon source, C. necator H16 yielded a relatively good dry cell weight (DCW=25.4 g/L, with 71 wt% poly(3-hydroxybutyrate P(3HBcontent. In comparison, the DCW obtained with fresh cooking oil (FCO was 24.8 g/L. The production of poly(3 hydroxybutyrate-co-3- hydroxyhexanoate [P(3HB-co-3HHx] from WCO by the transformant C. necator PHB¯4 was comparable, yielding a DCW of 22.3 g/L and P(3HB-co-3HHx content of 85 wt%. Lipase activities for both bacterial strains reached a maximum after 72 h of cultivation when time profile was conducted. Conclusion, significance and impact of study: The use of WCO as a carbon source in the biosynthesis of the bioplastic, PHA, turns a polluting domestic waste into a value-added biodegradable product. This renewable source material can thus be exploited for the low cost production of PHA.

  4. 3-Hydroxypropionic acid production by recombinant Escherichia coli ZJU-3HP01 using glycerol-glucose dual-substrate fermentative strategy.

    Science.gov (United States)

    Niu, Kun; Xiong, Tao; Qin, Hai-Bin; Wu, Hao; Liu, Zhi-Qiang; Zheng, Yu-Guo

    2017-07-01

    3-Hydroxypropionic acid (3-HP) is an important platform synthesis block for sets of chemicals, but the relatively low production of 3-HP from biological sources presented major barriers for its industrial applications. In this study, a dual-substrate fermentative strategy by glycerol and glucose was proposed, and the aim was to evaluate the effect of different substrate addition strategies on the fermentation process. The results indicated that the optimal cosubstrate was glucose (20 g/L), and the enzymatic activity of aldehyde dehydrogenase (AldH) could be improved 3.5-fold as compared with no glucose addition. Continuous fed-batch fermentation at a constant speed displayed better 3-HP production of 17.20 g/L and highest specific 3-HP productivity of 1.79 mmol/(g cell·H) than the other fed-batch mode. The addition of glucose could greatly reduce the imbalance of the activity between glycerol dehydratase and AldH and provide a feasible method for improving 3-HP production. These results would be helpful in developing the 3-HP fermentation process. © 2016 International Union of Biochemistry and Molecular Biology, Inc.

  5. POLY(3-HYDROXYBUTYRATE) PRODUCTION BY Cupriavidus necator SUPPLEMENTED WITH MINIEMULSIFIED SOYBEAN OIL

    OpenAIRE

    Schmidt, M.; Ienczak, J. L.; Quines, L. K.; Zanfonato, K.; Schmidell, W.; Aragão, G. M. F.

    2016-01-01

    Abstract Studies have shown that the supplementation of vegetable oils, in poly(3-hydroxybutyrate) production, provides an increase in the process productivity, besides inducing lipase activity in the medium. The supplementation with miniemulsified oils could potentialize these results. In this work, the influence of supplementation of the medium with soybean oil, without treatment and miniemulsified, on polymerr production was evaluated. The best moment to supplement the medium and its influ...

  6. Chemical modification of biodegradable polymer poly(3-hydroxybutyrate) by poly(ethylene oxide)

    International Nuclear Information System (INIS)

    Almeida, Lilian L.; Rocha, Gisele A.; Hui, Wang S.

    2009-01-01

    Catalyzed transesterification in the melt was used to produce triblock copolymers from poly(3-hydroxybutyrate) (PHB) and poly(ethyleneoxide) (PEG), in a simplified process. PHB of high molecular weight was depolymerized by pyrolysis and transesterification with dihydroxy terminated PEG occurred through consecutive and partly simultaneous reactions. The effectiveness of the process was verified by the characterization of the formed copolymers by Hydrogen and Carbon-13 Nuclear Magnetic Resonance Spectroscopies (NMR) and solubility analysis in a series of solvents. (author)

  7. Feeding strategies for tuning poly (3-hydroxybutyrate-co-4-hydroxybutyrate) monomeric composition and productivity using Burkholderia sacchari.

    Science.gov (United States)

    Raposo, Rodrigo S; de Almeida, M Catarina M D; da Fonseca, M M R; Cesário, M Teresa

    2017-12-01

    Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-4HB)) co-polymers were produced at bench-scale in fed-batch cultivations by Burkholderia sacchari from glucose (main carbon-source) and gamma-butyrolactone (GBL) as co-substrate. As P(3HB-4HB) properties highly depend on the 4-hydroxybutyrate (4HB) molar fraction, it is advantageous to have a thorough knowledge of the process in order to promote the production of the targeted final product. In this work, polymers with a 4HB molar percentage ranging from 1.5 to 8.4% (mol/mol) were obtained as consequence of a fine tuning of the fed-batch operation conditions, namely regarding the co-substrate feeding rate and its addition time, as GBL is toxic to B. sacchari cells. The best results regarding both the 4HB incorporation (molar%) and the co-polymer productivity (7.1% and 1.1g/(L.h) respectively) were reached when a pulse of GBL (<10g/L) was added early in the accumulation phase followed by a constant GBL addition at a rate similar to that of consumption so that a steady co-substrate concentration in the medium was maintained. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Production of polyhydroxybutyrate and alginate from glycerol by Azotobacter vinelandii under nitrogen-free conditions.

    Science.gov (United States)

    Yoneyama, Fuminori; Yamamoto, Mayumi; Hashimoto, Wataru; Murata, Kousaku

    2015-01-01

    Glycerol is an interesting feedstock for biomaterials such as biofuels and bioplastics because of its abundance as a by-product during biodiesel production. Here we demonstrate glycerol metabolism in the nitrogen-fixing species Azotobacter vinelandii through metabolomics and nitrogen-free bacterial production of biopolymers, such as poly-d-3-hydroxybutyrate (PHB) and alginate, from glycerol. Glycerol-3-phosphate was accumulated in A. vinelandii cells grown on glycerol to the exponential phase, and its level drastically decreased in the cells grown to the stationary growth phase. A. vinelandii also overexpressed the glycerol-3-phosphate dehydrogenase gene when it was grown on glycerol. These results indicate that glycerol was first converted to glycerol-3-phosphate by glycerol kinase. Other molecules with industrial interests, such as lactic acid and amino acids including γ-aminobutyric acid, have also been accumulated in the bacterial cells grown on glycerol. Transmission electron microscopy revealed that glycerol-grown A. vinelandii stored PHB within the cells. The PHB production level reached 33% per dry cell weight in nitrogen-free glycerol medium. When grown on glycerol, alginate-overproducing mutants generated through chemical mutagenesis produced 2-fold the amount of alginate from glycerol than the parental wild-type strain. To the best of our knowledge, this is the first report on bacterial production of biopolymers from glycerol without addition of any nitrogen source.

  9. Water and vapor permeability at different temperatures of poly (3-Hydroxybutyrate dense membranes

    Directory of Open Access Journals (Sweden)

    Luiz H. Poley

    2005-03-01

    Full Text Available Polyhydroxyalkanoates (PHAs are polymers produced from renewable resources with biodegradability and biocompatibility, being therefore attractive for medical and pharmaceutical purposes. Poly (3-hydroxybutyrate (PHB is the most important polymer of this family by considering the biotechnology process of its synthesis. In the present study, dense films of PHB were prepared by casting from chloroform solutions (1% m/m. Permeability studies with water, methanol, ethanol and n-propanol were performed using the gravimetric method at different temperatures (from 50 ºC to 65 ºC. Results provide new data on permeability coefficients of PHB membranes.

  10. Nanofiber-bonded cloth materials based on poly-3-hydroxybutyrate with antibacterial properties for medical purposes

    Science.gov (United States)

    Tyubaeva, P. M.; Olkhov, A. A.; Karpova, S. G.; Iordansky, A. L.; Popov, A. A.

    2017-12-01

    Different transdermal systems based on solid polymer matrices or gels containing functional substances with antiseptic (antibacterial) properties have application to the therapy of many infectious diseases and cancer. Today the most promising type of matrices with antiseptic characteristics are the nano- and microfiber nonwoven materials. Fibers on the biopolymer (poly(3-hydroxybutyrate)) basis were obtained using the electrospinning method. In the present work, the effects of iron (III) complex with tetraphenylporphyrin and its influence on bactericidal and antibacterial properties of the ultrathin PHB fibers were investigated.

  11. Analysis of structure of hyperfine poly(3-hydroxybutyrate) fibers (PHB) for controlled drug delivery

    Science.gov (United States)

    Olkhov, A. A.; Kosenko, R. Yu; Markin, V. S.; Zykova, A. K.; Pantyukhov, P. V.; Karpova, S. G.; Iordanskii, A. L.

    2017-12-01

    Hyperfine fibers based on biodegradable poly (3-hydroxybutyrate) with encapsulated drug substance (dipyridamol) were obtained by using electrospinning method. Addition of dipyridamol has a significant effect on geometrical shape and structure of microfibers as well as total porosity of fibrous material. Observation of fibers using scanning electron microscopy (SEM) method showed that without or at lower dipyridamol content (drug desorption from fibrous matrix was presented. In current work it was showed that the rate-limiting stage of transport was the diffusion of dipyridamol in the bulk of cylindrical fibers.

  12. Kinetics, safety and tolerability of (R)-3-hydroxybutyl (R)-3-hydroxybutyrate in healthy adult subjects.

    Science.gov (United States)

    Clarke, Kieran; Tchabanenko, Kirill; Pawlosky, Robert; Carter, Emma; Todd King, M; Musa-Veloso, Kathy; Ho, Manki; Roberts, Ashley; Robertson, Jeremy; Vanitallie, Theodore B; Veech, Richard L

    2012-08-01

    Induction of mild states of hyperketonemia may improve physical and cognitive performance. In this study, we determined the kinetic parameters, safety and tolerability of (R)-3-hydroxybutyl (R)-3-hydroxybutyrate, a ketone monoester administered in the form of a meal replacement drink to healthy human volunteers. Plasma levels of β-hydroxybutyrate and acetoacetate were elevated following administration of a single dose of the ketone monoester, whether at 140, 357, or 714 mg/kg body weight, while the intact ester was not detected. Maximum plasma levels of ketones were attained within 1-2h, reaching 3.30 mM and 1.19 mM for β-hydroxybutyrate and acetoacetate, respectively, at the highest dose tested. The elimination half-life ranged from 0.8-3.1h for β-hydroxybutyrate and 8-14 h for acetoacetate. The ketone monoester was also administered at 140, 357, and 714 mg/kg body weight, three times daily, over 5 days (equivalent to 0.42, 1.07, and 2.14 g/kg/d). The ketone ester was generally well-tolerated, although some gastrointestinal effects were reported, when large volumes of milk-based drink were consumed, at the highest ketone monoester dose. Together, these results suggest ingestion of (R)-3-hydroxybutyl (R)-3-hydroxybutyrate is a safe and simple method to elevate blood ketone levels, compared with the inconvenience of preparing and consuming a ketogenic diet. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Accumulation of Poly(3-hydroxybutyrate Helps Bacterial Cells to Survive Freezing.

    Directory of Open Access Journals (Sweden)

    Stanislav Obruca

    Full Text Available Accumulation of polyhydroxybutyrate (PHB seems to be a common metabolic strategy adopted by many bacteria to cope with cold environments. This work aimed at evaluating and understanding the cryoprotective effect of PHB. At first a monomer of PHB, 3-hydroxybutyrate, was identified as a potent cryoprotectant capable of protecting model enzyme (lipase, yeast (Saccharomyces cerevisiae and bacterial cells (Cupriavidus necator against the adverse effects of freezing-thawing cycles. Further, the viability of the frozen-thawed PHB accumulating strain of C. necator was compared to that of the PHB non-accumulating mutant. The presence of PHB granules in cells was revealed to be a significant advantage during freezing. This might be attributed to the higher intracellular level of 3-hydroxybutyrate in PHB accumulating cells (due to the action of parallel PHB synthesis and degradation, the so-called PHB cycle, but the cryoprotective effect of PHB granules seems to be more complex. Since intracellular PHB granules retain highly flexible properties even at extremely low temperatures (observed by cryo-SEM, it can be expected that PHB granules protect cells against injury from extracellular ice. Finally, thermal analysis indicates that PHB-containing cells exhibit a higher rate of transmembrane water transport, which protects cells against the formation of intracellular ice which usually has fatal consequences.

  14. Accumulation of Poly(3-hydroxybutyrate) Helps Bacterial Cells to Survive Freezing

    Science.gov (United States)

    Krzyzanek, Vladislav; Mravec, Filip; Hrubanova, Kamila; Samek, Ota; Kucera, Dan; Benesova, Pavla; Marova, Ivana

    2016-01-01

    Accumulation of polyhydroxybutyrate (PHB) seems to be a common metabolic strategy adopted by many bacteria to cope with cold environments. This work aimed at evaluating and understanding the cryoprotective effect of PHB. At first a monomer of PHB, 3-hydroxybutyrate, was identified as a potent cryoprotectant capable of protecting model enzyme (lipase), yeast (Saccharomyces cerevisiae) and bacterial cells (Cupriavidus necator) against the adverse effects of freezing-thawing cycles. Further, the viability of the frozen–thawed PHB accumulating strain of C. necator was compared to that of the PHB non-accumulating mutant. The presence of PHB granules in cells was revealed to be a significant advantage during freezing. This might be attributed to the higher intracellular level of 3-hydroxybutyrate in PHB accumulating cells (due to the action of parallel PHB synthesis and degradation, the so-called PHB cycle), but the cryoprotective effect of PHB granules seems to be more complex. Since intracellular PHB granules retain highly flexible properties even at extremely low temperatures (observed by cryo-SEM), it can be expected that PHB granules protect cells against injury from extracellular ice. Finally, thermal analysis indicates that PHB-containing cells exhibit a higher rate of transmembrane water transport, which protects cells against the formation of intracellular ice which usually has fatal consequences. PMID:27315285

  15. An Electrochemical Enzyme Biosensor for 3-Hydroxybutyrate Detection Using Screen-Printed Electrodes Modified by Reduced Graphene Oxide and Thionine

    Directory of Open Access Journals (Sweden)

    Gonzalo Martínez-García

    2017-11-01

    Full Text Available A biosensor for 3-hydroxybutyrate (3-HB involving immobilization of the enzyme 3-hydroxybutyrate dehydrogenase onto a screen-printed carbon electrode modified with reduced graphene oxide (GO and thionine (THI is reported here. After addition of 3-hydroxybutyrate or the sample in the presence of NAD+ cofactor, the generated NADH could be detected amperometrically at 0.0 V vs. Ag pseudo reference electrode. Under the optimized experimental conditions, a calibration plot for 3-HB was constructed showing a wide linear range between 0.010 and 0.400 mM 3-HB which covers the clinically relevant levels for diluted serum samples. In addition, a limit of detection of 1.0 µM, much lower than that reported using other biosensors, was achieved. The analytical usefulness of the developed biosensor was demonstrated via application to spiked serum samples.

  16. Measurement of milk D-3-hydroxybutyrate with a simple UV spectrophotometer method: an alternative assay method.

    Science.gov (United States)

    Zhang, Z G; Liu, G W; Li, X B; Li, Y F; Guo, C M; Gao, L; Wang, H B; Xu, S W; Wang, Z

    2009-01-01

    The measurement of D-3-hydroxybutyrate (D-BHBA) in milk samples is an important tool for diagnosis of subclinical/clinical ketosis in dairy cows. We describe a simple UV spectrophotometric method for measuring the concentration of D-BHBA in milk of dairy cows. From two herds, 119 milk samples were taken from dairy cows. The standard-curve equation was y = 0.2582x + 0.0269 (R2 = 0.9967). The assay was highly specific with a minimum detection limit of 0.01 mmol/L and measuring range of up to 5 mmol/L. The recovery was between 99.35% and 100.22% and repeatability was 99.8%. The comparison between the spectrophotometric method and the fluorometric method revealed a close correlation (r = 0.9939). These results show that the spectrophotometric method can be successfully used as an alternative method to measure D-BHBA content in milk.

  17. Novel Poly[(R-3-Hydroxybutyrate]-Producing Bacterium Isolated from a Bolivian Hypersaline Lake

    Directory of Open Access Journals (Sweden)

    María Soledad Marqués-Calvo

    2013-01-01

    Full Text Available Poly[(R-3-hydroxybutyrate] (PHB constitutes a biopolymer synthesized from renewable resources by various microorganisms. This work focuses on finding a new PHB-producing bacterium capable of growing in conventional media used for industrial biopolymer production, its taxonomical identification, and characterization of its biopolymer. Thus, a bacterial isolation process was carried out from environmental samples of water and mud. Among the isolates, strain S29 was selected and used in a fed-batch fermentation to generate a biopolymer. This biopolymer was recovered and identified as PHB homopolymer. Surprisingly, it featured several fractions of different molecular masses, and thermal properties unusual for PHB. Hence, the microorganism S29, genetically identified as a new strain of Bacillus megaterium, proved to be interesting not only due to its growth and PHB accumulation kinetics under the investigated cultivation conditions, but also due to the thermal properties of the produced PHB.

  18. Plasticity and X-ray Line Profile Analysis of the semicrystalline polymer poly(3-hydroxybutyrate)

    Energy Technology Data Exchange (ETDEWEB)

    Spieckermann, F; Wilhelm, H; Schafler, E; Kerber, M; Zehetbauer, M J [Research Group Physics of Nanostructured Materials, Faculty of Physics, University of Vienna, Boltzmanngasse 5, Wien (Austria); Bernstorff, S [Sincrotrone ELETTRA Trieste, Strada Statale 14 - km 163.5 in AREA Science Park, 34012 Basovizza, Trieste (Italy)

    2010-07-01

    The evolution of the microstructure during compressive deformation of the biodegradable polymer poly(3-hydroxybutyrate) (P3HB) was investigated in-situ via X-ray diffraction using synchrotron radiation. Flow curves were measured in-situ together with X-ray profiles for several degrees of deformation. The profiles were analysed using Multi-Reflection X-ray Line Profile Analysis (MXPA) adapted by the authors for semicrystalline polymers providing lamella thickness, crystallinity, and the presence and density of dislocations as a function of the deformation. In contrast to previous investigations in {alpha} crystallised isotactic polypropylene ({alpha}-iPP), P3HB does not exhibit a deformation induced increase of the dislocation density which suggests mechanisms other than dislocations to be involved in plastic deformation of P3HB.

  19. Enzymatic reduction of levulinic acid by engineering the substrate specificity of 3-hydroxybutyrate dehydrogenase.

    Science.gov (United States)

    Yeon, Young Joo; Park, Hyung-Yeon; Yoo, Young Je

    2013-04-01

    Enzymatic reduction of levulinic acid (LA) was performed for the synthesis of 4-hydroxyvaleric acid (4HV)--a monomer of bio-polyester and a precursor of bio-fuels--using 3-hydroxybutyrate dehydrogenase (3HBDH) from Alcaligenes faecalis. Due to the catalytic inactivity of the wild-type enzyme toward LA, engineering of the substrate specificity of the enzyme was performed. A rational design approach with molecular docking simulation was applied, and a double mutant, His144Leu/Trp187Phe, which has catalytic activity (kcat/Km=578.0 min(-1) M(-1)) toward LA was generated. Approximately 57% conversion of LA to 4HV was achieved with this double mutant in 24 h, while no conversion was achieved with the wild-type enzyme. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Graphene reinforced biodegradable poly(3-hydroxybutyrate-co-4-hydroxybutyrate nano-composites

    Directory of Open Access Journals (Sweden)

    V. Sridhar

    2013-04-01

    Full Text Available Novel biodegradable poly(3-hydroxybutyrate-co-4-hydroxybutyrate [PHBV]/graphene nanocomposites were prepared by solution casting. The thermal properties, crystallization behavior, microstructure, and fracture morphology of the composites were investigated. Scanning electron microscope (SEM results show that graphene layers are homogeneously dispersed in the polymer matrix. X-ray diffraction (XRD and dynamic scanning calorimetry (DSC studies show that the well dispersed graphene sheets act as nucleating agent for crystallization. Consequently, the mechanical properties of the composites have been substantially improved as evident from dynamic mechanical and static tensile tests. Differential thermal analysis (DTA showed an increase in temperature of maximum degradation. Soil degradation tests of PHBV/graphene nanocomposites showed that presence of graphene doesn’t interfere in its biodegradability.

  1. Lactose in milk replacer can partly be replaced by glucose, fructose, or glycerol without affecting insulin sensitivity in veal calves

    NARCIS (Netherlands)

    Pantophlet, A. J.; Gilbert, M. S.; van den Borne, J. J. G. C.; Gerrits, W. J. J.; Roelofsen, H.; Priebe, M. G.; Vonk, R. J.

    Calf milk replacer (MR) contains 40 to 50% lactose. Lactose strongly fluctuates in price and alternatives are desired. Also, problems with glucose homeostasis and insulin sensitivity (i.e., high incidence of hyperglycemia and hyperinsulinemia) have been described for heavy veal calves (body weight

  2. Lactose in milk replacer can partly be replaced by glucose, fructose, or glycerol without affecting insulin sensitivity in veal calves

    NARCIS (Netherlands)

    Pantophlet, A.J.; Gilbert, M.S.; Borne, van den J.J.G.C.; Gerrits, W.J.J.; Roelofsen, H.; Priebe, M.G.; Vonk, R.J.

    2016-01-01

    Calf milk replacer (MR) contains 40 to 50% lactose. Lactose strongly fluctuates in price and alternatives are desired. Also, problems with glucose homeostasis and insulin sensitivity (i.e., high incidence of hyperglycemia and hyperinsulinemia) have been described for heavy veal calves (body

  3. Microbial production and characterization of poly-3-hydroxybutyrate by Neptunomonas antarctica

    Directory of Open Access Journals (Sweden)

    Xiao-Jie Liu

    2016-08-01

    Full Text Available Considering the industrial interest of biodegradable polymer poly-3-hydroxybutyrate (PHB, the marine bacteria Neptunomonas antarctica was studied for its ability to accumulate PHB. The extracted polymer was confirmed to be PHB by nuclear magnetic resonance analysis. In shake flask cultures using natural seawater as medium components, PHB was produced up to 2.12 g/L with a yield of 0.18 g PHB/g fructose. In the presence of artificial seawater, the PHB titer and yield reached 2.13 g/L and 0.13 g PHB/g fructose, respectively. The accumulated polymer gradually decreased when fructose was exhausted, indicating that intracellular PHB was degraded by N. antarctica. The weight-average and number-average molecular weights of PHB produced within natural seawater were 2.4 × 105 g/mol and 1.7 × 105 g/mol, respectively. Our results highlight the potential of N. antarctica for PHB production with seawater as a nutrient source.

  4. Targeted poly(3-hydroxybutyrate-co-3-hydroxyvalerate) bioplastic production from carbon dioxide.

    Science.gov (United States)

    Ghysels, Stef; Mozumder, Md Salatul Islam; De Wever, Heleen; Volcke, Eveline I P; Garcia-Gonzalez, Linsey

    2018-02-01

    A microbial production process was developed to convert CO 2 and valeric acid into tailored poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) bioplastics. The aim was to understand microbial PHBV production in mixotrophic conditions and to control the monomer distribution in the polymer. Continuous sparging of CO 2 with pulse and pH-stat feeding of valeric acid were evaluated to produce PHBV copolyesters with predefined properties. The desired random monomer distribution was obtained by limiting the valeric acid concentration (below 1 gL -1 ). 1 H-NMR, 13 C-NMR and chromatographic analysis of the PHBV copolymer confirmed both the monomer distribution and the 3-hydroxyvalerate (3HV) fraction in the produced PHBV. A physical-based model was developed for mixotrophic PHBV production, which was calibrated and validated with independent experimental datasets. To produce PHBV with a predefined 3HV fraction, an operating diagram was constructed. This tool was able to predict the 3HV fraction with a very good accuracy (2% deviation). Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Identification of gene disruptions for increased poly-3-hydroxybutyrate accumulation in Synechocystis PCC 6803.

    Science.gov (United States)

    Tyo, Keith E J; Jin, Yong-Su; Espinoza, Freddy A; Stephanopoulos, Gregory

    2009-01-01

    Inverse metabolic engineering (IME) is a combinatorial approach for identifying genotypes associated with a particular phenotype of interest. In this study, gene disruptions that increase the biosynthesis of poly-3-hydroxybutyrate (PHB) in the photosynthetic bacterium Synechocystis PCC6803 were identified. A Synechocystis mutant library was constructed by homologous recombination between the Synechocystis genome and a mutagenized genomic plasmid library generated through transposon insertion. Using a fluorescence-activated cell sorting-based high throughput screen, high PHB accumulating mutants from the library grown in different nutrient conditions were isolated and characterized. While several mutants isolated from the screen had increased PHB accumulation, transposon insertions in only two ORFs could be linked to increased PHB production. Disruptions of sll0461, coding for gamma-glutamyl phosphate reductase (proA), and sll0565, a hypothetical protein, resulted in increased accumulation in standard growth media and acetate supplemented media. These genetic perturbations have increased PHB accumulation in Synechocystis and serve as markers for engineering increased polymer production in higher photosynthetic organisms. 2009 American Institute of Chemical Engineers Biotechnol.

  6. Synthesis, characterization and antimicrobial activity of biguanidinylated chitosan-g-poly[(R)-3-hydroxybutyrate].

    Science.gov (United States)

    Salama, Hend E; Saad, Gamal R; Sabaa, Magdy W

    2017-08-01

    Chitosan biguanidine hydrochloride (ChG) and low molecular weight poly[(R)-3-hydroxybutyrate] (PHB) were successfully prepared to overcome the solubility problem of chitosan and PHB and also to enhance antimicrobial activity of chitosan. The graft copolymers based on ChG and PHB (ChG-grafted PHB) were then prepared via condensation reaction of the carboxylic groups of PHB with the amino groups of ChG. These graft copolymers swell in water. The prepared graft copolymers were characterized by FTIR, 1 H NMR, X-ray diffraction (XRD) and thermal analyses (TGA and DSC). TGA and DSC results revealed that the thermal stability and crystallinity of the graft copolymers were found to increase as the content of PHB increased. The antimicrobial activity of both ChG and ChG-grafted PHB, against Streptococcus pneumoniae, Bacillus subtilis, Escherichia coli (as examples of bacteria) and Aspergillus fumigatus, Geotricum candidum and Syncephalastrum recemosum (as examples of fungi), were tested. Among them, ChG and ChG-grafted PHB with the highest grafting percent investigated showed to possess relatively higher antimicrobial activity with low MIC values in the range of 0.49-3.90μgmL -1 . Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Cyanobacteria Biorefinery - Production of poly(3-hydroxybutyrate) with Synechocystis salina and utilisation of residual biomass.

    Science.gov (United States)

    Meixner, K; Kovalcik, A; Sykacek, E; Gruber-Brunhumer, M; Zeilinger, W; Markl, K; Haas, C; Fritz, I; Mundigler, N; Stelzer, F; Neureiter, M; Fuchs, W; Drosg, B

    2018-01-10

    This study evaluates a biorefinery concept for producing poly(3-hydroxybutyrate) (PHB) with the cyanobacterial strain Synechocystis salina. Due to this reason, pigment extraction and cell disruption were investigated as pre-treatment steps for the harvested cyanobacterial biomass. The results demonstrated that at least pigment removal was necessary to obtain PHB with processable quality (weight average molecular weight: 569-988kgmol -1 , melting temperature: 177-182°C), which was comparable to heterotrophically produced PHB. The removed pigments could be utilised as additional by-products (chlorophylls 0.27-1.98mgg -1 TS, carotenoids 0.21-1.51mgg -1 TS, phycocyanin 0-127mgg -1 TS), whose concentration depended on the used nutrient source. Since the residual biomass still contained proteins (242mgg -1 TS), carbohydrates (6.1mgg -1 TS) and lipids (14mgg -1 TS), it could be used as animal feed or converted to biomethane (348 m n 3 t -1 VS) and fertiliser. The obtained results indicate that the combination of photoautotrophic PHB production with pigment extraction and utilisation of residual biomass offer the highest potential, since it contributes to decrease the environmental footprint of the process and because biomass could be used in a cascading way and the nutrient cycle could be closed. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Phase diagrams in blends of poly(3-hydroxybutyric acid with various aliphatic polyesters

    Directory of Open Access Journals (Sweden)

    2011-07-01

    Full Text Available Phase behavior with immiscibility, miscibility, crystalline morphology, and kinetic analysis in blends of poly(3-hydroxybutyric acid (PHB with aliphatic polyesters such as poly(butylene adipate (PBA, poly(ethylene adipate (PEA, poly(trimethylene adipate (PTA, or poly(ethylene succinate (PESu, respectively, were explored mainly using differential scanning calorimeter (DSC and polarized-light optical microscopy (POM. Immiscibility phase behavior with reversible upper-critical-solution-temperature (UCST is common in the PHB/polyester blends. The polyester/polyester blend of PHB/PTA is partially miscible with no UCST in melt and amorphous glassy states within a composition range of PTA less than 50 wt%. The miscible crystalline/crystalline blend exhibits ring-banded spherulites at Tc = 50~100°C, with inter-ring spacing dependent on Tc. All immiscible or partially miscible PHB/polyester blends, by contrast, exhibit disrupted ringbanded spherulites or discrete spherical phase domains upon cooling from UCST to crystallization. The blends of PHB with all other aliphatic polyesters, such as PESu, PEA, PBA, etc. are only partially miscible or immiscible with an upper critical solution temperature (UCST at 180~221°C depending on blend composition. UCST with reversibility was verified.

  9. Dexamethasone-loaded poly(3-hydroxybutyrate-co-3-hydroxyvalerate) microparticles for controlled release

    International Nuclear Information System (INIS)

    Riekes, Manoela Klueppel; Paula, Josiane Padilha de; Farago, Paulo Vitor; Zawadzki, Sonia Faria

    2009-01-01

    Dexamethasone (DEX) has been widely used for the treatment of ulcerative colitis. The aim of the present study was to obtain DEX-loaded poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) microparticles prepared by simple emulsion/solvent evaporation method. The drug loading and the encapsulation efficiency were determined by a previously validated UV method at 233 nm. Morphological, spectroscopical and dissolution analyses were also performed. The microparticles (formulation F no. 0, F no. 1 and F no. 2) were successfully obtained as off-white powders. A drug loading of 92.27 mg.g -1 and 218.54 mg.g -1 and an encapsulation efficiency of 93.96 % and 87.43 % were respectively observed for F no. 1 and F no. 2. Particles showed spherical and rough aspect by SEM. X-ray diffraction analysis demonstrated that the encapsulation reduced the drug crystallinity. FTIR spectra showed that no chemical bonding occurred between PHBV and DEX. Drug-loaded microparticles revealed controlled release profiles compared to pure DEX. (author)

  10. Effect of Graphite Nanosheets on Properties of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate

    Directory of Open Access Journals (Sweden)

    Larissa Stieven Montagna

    2017-01-01

    Full Text Available The influence of different contents, 0.25, 0.50, and 1.00 wt%, of graphite nanosheets (GNS on the properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV nanocomposites obtained by solution casting method has been studied. GNS were prepared by three steps: intercalation (chemical exfoliation, expansion (thermal treatment, and the GNS obtainment (physical treatment by ultrasonic exfoliation. X-ray diffraction (XRD, Raman spectroscopy, and field emission gun-scanning electron microscopy (FE-SEM showed that the physical, chemical, and thermal treatments preserved the graphite sheets structure. XRD and Raman results also showed that GNS were dispersed in the PHBV matrix. The degree of crystallinity (Xc of the nanocomposites did not change when the graphite nanosheets were added. However, the GNS acted as nucleation agent for crystallization; that is, in the second heating the samples containing GNS showed two melting peaks. The addition the GNS did not change the thermal stability of the PHBV.

  11. Does the tissue engineering architecture of poly(3-hydroxybutyrate) scaffold affects cell-material interactions?

    Science.gov (United States)

    Masaeli, Elahe; Morshed, Mohammad; Rasekhian, Parsa; Karbasi, Saeed; Karbalaie, Khadije; Karamali, Fereshte; Abedi, Daryoush; Razavi, Shahnaz; Jafarian-Dehkordi, Abbas; Nasr-Esfahani, Mohammad Hossein; Baharvand, Hossein

    2012-07-01

    A critical element in tissue engineering involves the fabrication of a three-dimensional scaffold. The scaffold provides a space for new tissue formation, supports cellular ingrowth, and proliferation and mimics many roles of the extracellular matrix. Poly(3-hydroxybutyrate) (PHB) is the most thoroughly investigated member of the polyhydroxyalkanoates (PHAs) family that has various degrees of biocompatibility and biodegradability for tissue engineering applications. In this study, we fabricated PHB scaffolds by utilizing electrospinning and salt-leaching procedures. The behavior of monkey epithelial kidney cells (Vero) and mouse mesenchymal stem cells (mMSCs) on these scaffolds was compared by the MTS assay and scanning electron microscopy. Additionally, this study investigated the mechanical and physical properties of these scaffolds by measuring tensile strength and modulus, dynamic contact angle and porosity. According to our results, the salt-leached scaffolds showed more wettability and permeability, but inferior mechanical properties when compared with nanofibrous scaffolds. In terms of cell response, salt-leached scaffolds showed enhanced Vero cell proliferation, whereas both scaffolds responded similarly in the case of mMSCs proliferation. In brief, nanofibrous scaffolds can be a better substrate for cell attachment and morphology. Copyright © 2012 Wiley Periodicals, Inc.

  12. Poly(3-hydroxybutyrate) production in an integrated electromicrobial setup: Investigation under stress-inducing conditions

    KAUST Repository

    Al Rowaihi, Israa Salem

    2018-04-26

    Poly(3-hydroxybutyrate) (PHB), a biodegradable polymer, can be produced by different microorganisms. The PHB belongs to the family of polyhydroxyalkanoate (PHA) that mostly accumulates as a granule in the cytoplasm of microorganisms to store carbon and energy. In this study, we established an integrated one-pot electromicrobial setup in which carbon dioxide is reduced to formate electrochemically, followed by sequential microbial conversion into PHB, using the two model strains, Methylobacterium extorquens AM1 and Cupriavidus necator H16. This setup allows to investigate the influence of different stress conditions, such as coexisting electrolysis, relatively high salinity, nutrient limitation, and starvation, on the production of PHB. The overall PHB production efficiency was analyzed in reasonably short reaction cycles typically as short as 8 h. As a result, the PHB formation was detected with C. necator H16 as a biocatalyst only when the electrolysis was operated in the same solution. The specificity of the source of PHB production is discussed, such as salinity, electricity, concurrent hydrogen production, and the possible involvement of reactive oxygen species (ROS).

  13. Poly(ɛ-caprolactone) composites reinforced by biodegradable poly(3-hydroxybutyrate-co-3-hydroxyvalerate) fiber.

    Science.gov (United States)

    Ju, Dandan; Han, Lijing; Li, Fan; Chen, Shan; Dong, Lisong

    2014-06-01

    Biodegradable and biosourced poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) fiber was used as a reinforcing agent, and environment friendly poly(ɛ-caprolactone) (PCL) composites were prepared by melt compounding. The mechanical properties, rheological properties, and enzymatic degradation of the PCL composites were investigated in detail. With the addition of PHBV fibers, the PCL composites showed increased tensile yielding strength and modulus. Especially, the storage modulus from the results of dynamic mechanical analysis was increased significantly, suggesting that PCL was obviously reinforced by adding PHBV fibers. With increasing the PHBV fiber content, the complex viscosity and modulus of PCL increased, especially at low frequencies, indicating that a network structure was formed in the composites. The network structure resulted in evident solid-like response due to the restriction of the chain mobility of PCL matrix, which was further confirmed by the Han and Cole-Cole plots. The morphology, evaluated by scanning electron microscopy, indicated PCL and PHBV fiber were not highly incompatible and the interfacial adhesion was good, which was beneficial to the reinforcement effect. The biodegradability of the PCL was significantly promoted after composites preparation. Such studies are of great interest in the development of environment friendly composites from biodegradable polymers. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Investigation of miscibility of p(3hydroxybutyrate-co-3hydroxyhexanoate) and epoxidized natural rubber blends

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Faridah; Chan, Chin Han; Natarajan, Valliyappan David [Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, 40450 Selangor Darul Ehsan (Malaysia)

    2015-08-28

    Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate [P(3HB-co-3HHx)] produced by C. necator PHB{sup −}4 harboring phaC{sub cs} from crude palm kernel oil with 21 mol% of 3-hydroxyhexanoate and epoxidized natural rubber with 25 mol% of epoxy content (ENR-25) were used to study the miscibility of the blends by attenuated total reflection-Fourier transform infrared (ATR-FTIR) and differential scanning calorimetry (DSC). The polymers used were purified and the blends were prepared by solution casting method. Nuclear magnetic resonance (NMR) spectra confirm the purity and molecular structures of P(3HB-co-3HHx) and ENR-25. FTIR spectra for different compositions of P(3HB-co-3HHx) and ENR-25 blends show absorbance change of the absorbance bands but with no significant shifting of the absorbance bands as the P(3HB-co-3HHx) content decreases, which shows that there is no intermolecular interaction between the parent polymer blends. On top of that, there are two T{sub g}s present for the blends and both remain constant for different compositions which corresponds to the T{sub g}s of the parent polymers. This indicates that the blends are immiscible.

  15. Investigation of miscibility of p(3hydroxybutyrate-co-3hydroxyhexanoate) and epoxidized natural rubber blends

    International Nuclear Information System (INIS)

    Akram, Faridah; Chan, Chin Han; Natarajan, Valliyappan David

    2015-01-01

    Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate [P(3HB-co-3HHx)] produced by C. necator PHB − 4 harboring phaC cs from crude palm kernel oil with 21 mol% of 3-hydroxyhexanoate and epoxidized natural rubber with 25 mol% of epoxy content (ENR-25) were used to study the miscibility of the blends by attenuated total reflection-Fourier transform infrared (ATR-FTIR) and differential scanning calorimetry (DSC). The polymers used were purified and the blends were prepared by solution casting method. Nuclear magnetic resonance (NMR) spectra confirm the purity and molecular structures of P(3HB-co-3HHx) and ENR-25. FTIR spectra for different compositions of P(3HB-co-3HHx) and ENR-25 blends show absorbance change of the absorbance bands but with no significant shifting of the absorbance bands as the P(3HB-co-3HHx) content decreases, which shows that there is no intermolecular interaction between the parent polymer blends. On top of that, there are two T g s present for the blends and both remain constant for different compositions which corresponds to the T g s of the parent polymers. This indicates that the blends are immiscible

  16. Crystallization and alkaline hydrolysis of poly(3- hydroxybutyrate) films probed by thermal analysis and infrared spectroscopy.

    Science.gov (United States)

    Tapadiya, Asish; Vasanthan, Nadarajah

    2017-09-01

    Poly(3-hydroxybutyrate) (PHB) is a microbially synthesized polymer, which is often purified by alkaline treatment. The effect of microstructure on alkaline hydrolysis has been studied by varying concentration of base and the temperature. The morphologies of PHB films before and after degradation were evaluated using DSC and FTIR spectroscopy. The hydrolytic degradation study by weight loss measurement revealed that the crystallinity of PHB greatly decreased the hydrolytic ability of PHB. The crystallization of PHB and the effect of base on hydrolysis was investigated by time dependent FTIR spectroscopy. The normalized absorbance of 3010cm -1 and 1183cm -1 were used to characterize the crystalline and the amorphous phases of PHB. FTIR spectroscopy reveal that the extent of hydrolysis decreased with increasing crystallinity. The crotonic acid was detected as a major product after hydrolysis, confirmed by UV/Visible and proton NMR spectroscopy. The normalized absorbance of the crystalline band at 3010cm -1 band remained constant, suggesting that there is no significant change in crystallinity with degradation. The normalized amorphous band at 1183cm -1 showed a decrease in absorbance ratio, suggesting degradation of the amorphous phase. Our data suggests that alkaline hydrolysis depends on concentration of base and the crystallinity of PHB. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Engineering cyanobacteria for photosynthetic production of 3-hydroxybutyrate directly from CO2.

    Science.gov (United States)

    Wang, Bo; Pugh, Shawn; Nielsen, David R; Zhang, Weiwen; Meldrum, Deirdre R

    2013-03-01

    (S)- and (R)-3-hydroxybutyrate (3HB) are precursors to synthesize the biodegradable plastics polyhydroxyalkanoates (PHAs) and many fine chemicals. To date, however, their production has been restricted to petroleum-based chemical industry and sugar-based microbial fermentation, limiting its sustainability and economical feasibility. With the ability to fix CO2 photosynthetically, cyanobacteria have attracted increasing interest as a biosynthesis platform to produce fuels and chemicals from alternative renewable resources. To this end, synthesis metabolic pathways have been constructed and optimized in cyanobacterium Synechocystis sp. PCC 6803 to photosynthetically produce (S)- and (R)-3HB directly from CO2. Both types of 3HB molecules were produced and readily secreted from Synechocystis cells without over-expression of transporters. Additional inactivation of the competing pathway by deleting slr1829 and slr1830 (encoding PHB polymerase) from the Synechocystis genome further promoted the 3HB production. Up to 533.4mg/L 3HB has been produced after photosynthetic cultivation of the engineered cyanobacterium Synechocystis TABd for 21 days. Further analysis indicated that the phosphate consumption during the photoautrophic growth and the concomitant elevated acetyl-CoA pool acted as a key driving force for 3HB biosynthesis in Synechocystis. For the first time, the study has demonstrated the feasibility of photosynthetic production of (S)- and (R)-3HB directly from sunlight and CO2. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Glycolysis of poly(3-hydroxybutyrate) via enzyme catalysis; Glicolise do poli(3-hidroxibutirato) por via enzimatica

    Energy Technology Data Exchange (ETDEWEB)

    Paula, Everton Luiz de, E-mail: everton2804@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Quimica; Campos, Tiago Ferreira; Mano, Valdir [Universidade Federal de Sao Joao del-Rei (UFSJ), MG (Brazil). Departamento de Ciencias Naturais

    2014-05-15

    Poly(3-hydroxybutyrate), PHB, is a polymer with broad potential applications because of its biodegradability and biocompatibility. However, its high crystallinity is a limiting factor for many applications. To overcome this drawback, one strategy currently employed involves the reduction of the molecular weight of PHB with the concomitant formation of end-functionalized chains, such as those obtained via glycolysis. The glycolysis of PHB can be catalyzed by acid, base, or organometallic compounds. However, to our knowledge, there are no reports regarding PHB glycolysis catalyzed enzymatically. Among the major types of enzymes used in biocatalysis, the lipases stand out because they have the ability to catalyze reactions in both aqueous and organic media. Thus, in this study, we performed the enzymatic glycolysis of PHB using the lipase Amano PS (Pseudomonas cepacia) with ethane-1,2-diol (ethylene glycol) as the functionalizing agent. The results indicated that the glycolysis was successful and afforded hydroxyl-terminated oligomeric PHB polyols. Nuclear magnetic resonance spectra of the products showed characteristic signals for the terminal hydroxyl groups of the polyols, while thermogravimetric and differential scanning calorimetry analyses confirmed an increase in the thermal stability and a decrease in the crystallinity of the polyols compared with the starting PHB polymer, which were both attributed to the reduction in the molecular weight due to glycolysis. (author)

  19. Cost-effective synthesis of environmentally benign materials on the basis of poly-3-hydroxybutyrate

    Directory of Open Access Journals (Sweden)

    H. Häberlein

    2005-06-01

    Full Text Available As an example for an environmentally benign and low-cost material we prepared blends from 1. copolyester-urethanes (PEU and 2. cellulose acetate recycling material (CAR. The copolyester-urethanes were prepared by joining blocks of alpha, omega-(poly-(R-3-hydroxybutyrate-diol and poly-butylenglycol-adipate-diol with hexamethylene diisocyanate. Fibrous CAR was transformed into a short-fiber felt by textile technology and calendared into the PEU melt. The processing of the blends was done at 80 - 100 °C mainly by injection molding. The mechanical properties of the tough-elastic materials were studied with respect to the influence of the PEU composition and the ratio of CAR admixture. The starting materials, (R-PHB and cellulose derivatives are obtained from agrarian resources. Therefore, the resulting polymers are stable under conditions of usage, yet readily bio-degradable on soil deposition. Mixing with cellulose acetate waste material allows for cost-effective production of such blends.

  20. Controlled release profiles of dipyridamole from biodegradable microspheres on the base of poly(3-hydroxybutyrate.

    Directory of Open Access Journals (Sweden)

    2007-12-01

    Full Text Available Novel biodegradable microspheres on the base of poly(3-hydroxybutyrate (PHB designed for controlled release of antithrombotic drug, namely dipyridamole (DPD, have been kinetically studied. The profiles of release from the microspheres with different diameters 4, 9, 63, and 92 µm present the progression of nonlinear and linear stages. Diffusionkinetic equation describing both linear (PHB hydrolysis and nonlinear (diffusion stages of the DPD release profiles from the spherical subjects has been written down as the sum of two terms: desorption from the homogeneous sphere in accordance with diffusion mechanism and the zero-order release. In contrast to the diffusivity dependence on microsphere size, the constant characteristics (k of linearity are scarcely affected by the diameter of PHB microparticles. The view of the kinetic profiles as well as the low rate of DPD release are in satisfactory agreement with kinetics of weight loss measured in vitro for the PHB films. Taking into account kinetic results, we suppose that the degradation of both films and PHB microspheres is responsible for the linear stage of DPD release profiles. In the nearest future, combination of biodegradable PHB and DPD as a representative of proliferation cell inhibitors will give possibility to elaborate the novel injectable therapeutic system for a local, long-term, antiproliferative action.

  1. Characterization of biodegradable poly-3-hydroxybutyrate films and pellets loaded with the fungicide tebuconazole.

    Science.gov (United States)

    Volova, Tatiana; Zhila, Natalia; Vinogradova, Olga; Shumilova, Anna; Prudnikova, Svetlana; Shishatskaya, Ekaterina

    2016-03-01

    Biodegradable polymer poly(3-hydroxybutyrate) (P3HB) has been used as a matrix to construct slow-release formulations of the fungicide tebuconazole (TEB). P3HB/TEB systems constructed as films and pellets have been studied using differential scanning calorimetry, X-ray structure analysis, and Fourier transform infrared spectroscopy. TEB release from the experimental formulations has been studied in aqueous and soil laboratory systems. In the soil with known composition of microbial community, polymer was degraded, and TEB release after 35 days reached 60 and 36 % from films and pellets, respectively. That was 1.23 and 1.8 times more than the amount released to the water after 60 days in a sterile aqueous system. Incubation of P3HB/TEB films and pellets in the soil stimulated development of P3HB-degrading microorganisms of the genera Pseudomonas, Stenotrophomonas, Variovorax, and Streptomyces. Experiments with phytopathogenic fungi F. moniliforme and F. solani showed that the experimental P3HB/TEB formulations had antifungal activity comparable with that of free TEB.

  2. Poly(3-hydroxybutyrate/ZnO Bionanocomposites with Improved Mechanical, Barrier and Antibacterial Properties

    Directory of Open Access Journals (Sweden)

    Ana M. Díez-Pascual

    2014-06-01

    Full Text Available Poly(3-hydroxybutyrate (PHB-based bionanocomposites incorporating different contents of ZnO nanoparticles were prepared via solution casting technique. The nanoparticles were dispersed within the biopolymer without the need for surfactants or coupling agents. The morphology, thermal, mechanical, barrier, migration and antibacterial properties of the nanocomposites were investigated. The nanoparticles acted as nucleating agents, increasing the crystallization temperature and the degree of crystallinity of the matrix, and as mass transport barriers, hindering the diffusion of volatiles generated during the decomposition process, leading to higher thermal stability. The Young’s modulus, tensile and impact strength of the biopolymer were enhanced by up to 43%, 32% and 26%, respectively, due to the strong matrix-nanofiller interfacial adhesion attained via hydrogen bonding interactions, as revealed by the FT-IR spectra. Moreover, the nanocomposites exhibited reduced water uptake and superior gas and vapour barrier properties compared to neat PHB. They also showed antibacterial activity against both Gram-positive and Gram-negative bacteria, which was progressively improved upon increasing ZnO concentration. The migration levels of PHB/ZnO composites in both non-polar and polar simulants decreased with increasing nanoparticle content, and were well below the current legislative limits for food packaging materials. These biodegradable nanocomposites show great potential as an alternative to synthetic plastic packaging materials especially for use in food and beverage containers and disposable applications.

  3. Poly-3-hydroxybutyrate-co-3-hydroxyvalerate containing scaffolds and their integration with osteoblasts as a model for bone tissue engineering.

    Science.gov (United States)

    Zhang, Sai; Prabhakaran, Molamma P; Qin, Xiaohong; Ramakrishna, Seeram

    2015-05-01

    Nano/micro engineered polymeric materials offer expansive scope of biomimetic scaffolds for bone tissue engineering especially those involving electrospun biodegradable nanofibers incorporated with inorganic nanoparticles, thus mimicking the extracellular matrix of bone both structurally and chemically. For the first time, poly-3-hydroxybutyrate-co-3-hydroxyvalerate containing natural poly-(α, β)-DL-aspartic acid and inorganic hydroxyapatite nanofibers were fabricated using poly-3-hydroxybutyrate-co-3-hydroxyvalerate: poly-(α, β)-DL-aspartic acid at a ratio of 80:20 (w/w) added with 1% (w/v) of hydroxyapatite, by the process of electrospinning. The surface morphology, chemical, and mechanical properties of electrospun poly-3-hydroxybutyrate-co-3-hydroxyvalerate, poly-3-hydroxybutyrate-co-3-hydroxyvalerate/poly-(α, β)-DL-aspartic acid, and poly-3-hydroxybutyrate-co-3-hydroxyvalerate/poly-(α, β)-DL-aspartic acid/hydroxyapatite nanofibers were characterized by using field emission scanning electron microscope, Fourier transform infrared spectroscopy, and tensile tester, respectively. Human fetal osteoblasts were cultured on different nanofibrous scaffolds for evaluating the cell proliferation, alkaline phosphatase activity, and mineralization. Cells on poly-3-hydroxybutyrate-co-3-hydroxyvalerate/poly-(α, β)-DL-aspartic acid/hydroxyapatite scaffolds demonstrated higher proliferation (30.10%) and mineral deposition (37.60%) than the cells grown on pure poly-3-hydroxybutyrate-co-3-hydroxyvalerate scaffolds. Obtained results highlight the synergistic effect of poly-3-hydroxybutyrate-co-3-hydroxyvalerate, poly-(α, β)-DL-aspartic acid, and hydroxyapatite towards the enhancement of the osteoinductivity and osteoconductivity of human fetal osteoblasts, demonstrating the appropriate physicochemical and biological properties of poly-3-hydroxybutyrate-co-3-hydroxyvalerate/poly-(α, β)-DL-aspartic acid/hydroxyapatite nanofibers to function as a substrate for bone

  4. Topological characterization of nanocrystalline cellulose reinforced Poly (lactic acid) and Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) bionanocomposites

    Science.gov (United States)

    Bhat, A. H.; Dasan, Y. K.; Khan, Ihsan Ullah; Ahmad, Faiz; Ayoub, Muhammad

    2016-11-01

    This study was conducted to evaluate the morphological and barrier properties of nanocrystalline cellulose reinforced Poly (lactic acid) and Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) bionanocomposites. Nanocrystalline cellulose was isolated from waste oil palm empty fruit bunch fiber using Sulphuric acid hydrolysis. Chemical modifications of nanocrystalline cellulose was performed to allow good compatibilization between fiber and the polymer matrices and also to improve dispersion of fillers. Bionanocomposite materials were produced from these nanocrystalline cellulose reinforced Poly (lactic acid) and Poly-(3-hydroxybutyrate-co-3-hydroxyvalerate) using solvent casting and evaporation techniques. The properties of extracted nanocrystalline cellulose were examined using FT-IR spectroscopy, X-ray diffractometer, TEM and AFM. Besides that, the properties of bionanocomposites were examined through FESEM and oxygen permeability properties analysis. Better barrier and morphological properties were obtained for nanocrystalline cellulose reinforced bionanocomposites than for neat polymer blend.

  5. Study for poly[(R)-3-hydroxybutyrate] production by bacterial strains and its modification for drug delivery systems

    OpenAIRE

    Rodríguez Contreras, Alejandra María

    2013-01-01

    Nowadays biopolymers are a good alternative to petrochemical polymers. One of these biopolymers is Poly[(R)-3- Hydroxybutyrate] (PHB) which is produced from renewable resources by various microorganisms and, after its use it can be composted. It has different applications as bulk material in packing films, containers or paper coatings. Due to its excellent biocompatibility and biodegradability, PHB is a potential material for applications in drug delivery. It is therefore important t...

  6. Draft Genome Sequence of Bacillus aryabhattai Strain PHB10, a Poly(3-Hydroxybutyrate)-Accumulating Bacterium Isolated from Domestic Sewerage.

    Science.gov (United States)

    Balakrishna Pillai, Aneesh; Jaya Kumar, Arjun; Thulasi, Kavitha; Reghunathan, Dinesh; Prasannakumar, Manoj; Kumarapillai, Harikrishnan

    2017-10-12

    Bacillus aryabhattai PHB10 is a poly(3-hydroxybutyrate) (PHB)-accumulating bacterium isolated from domestic sewerage. Here, we report the 4.19-Mb draft genome sequence, with 4,050 protein-coding genes and a G+C content of 37.5%. This sequence will be helpful in the study of the high-level PHB accumulation mechanism of the strain. Copyright © 2017 Balakrishna Pillai et al.

  7. Effect of water absorption on the mechanical properties of poly(3-hydroxybutyrate)/vegetable fiber composites

    Science.gov (United States)

    Marinho, Vithória A. D.; Carvalho, Laura H.; Canedo, Eduardo L.

    2015-05-01

    The present work studies the effect of water absorption on the performance of composites of poly(3-hydroxybutyrate) (PHB) - a fully biodegradable semi-crystalline thermoplastic obtained from renewable resources through low-impact biotechnological process, biocompatible and non-toxic - and vegetable fiber from the fruit (coconut) of babassu palm tree.Water resistance is an important characteristic of structural composites, that may exposed to rain and humid environments. Both water absorption capacity (water solubility in the material) and the rate of water absorption (controlled by the diffusivity of water in the material) are important parameters. However, water absorption per se may not be the most important characteristic, insofar as the performance and applications of the compounds. It is the effect of the water content on the ultimate properties that determine the suitability of the material for applications that involve prolonged exposure to water.PHB/babassu composites with 0-20% load were prepared in an internal mixer. Two different types of babassu fibers having two different article size ranges were compounded with PHB and test specimens molded by compression. The water absorption capacity and the kinetic constant of water absorption were measured in triplicate. Mechanical properties under tension were measured for dry and moist specimens with different amounts of absorbed water.Results indicate that the performance of the composites is comparable to that of the pure matrix. Water absorption capacity increases from 0.7% (pure PHB) to 4% (PHB/20% babassu), but the water diffusivity (4.10□8 cm2/s) was found to be virtually independent of the water absorption level. Water absorption results in moderate drop in elastic modulus (10-30% at saturation, according to fiber content) but has little effect on tensile strength and elongation at break. Fiber type and initial particle size do not have a significant effect on water absorption or mechanical properties.

  8. High cell density strategy for poly(3-hydroxybutyrate production by Cupriavidus necator

    Directory of Open Access Journals (Sweden)

    J. L. Ienczak

    2011-12-01

    Full Text Available Poly(3-hydroxybutyrate (P(3HB is a carbon and intracellular storage source for different microorganisms and its production can achieve high productivities by means of high cell density cultures. The aim of this study was to propose a high cell density strategy for P(3HB production by Cupriavidus necator. The exponential growth phase demands an accurate control of the oxygen transfer system in the bioreactor, due to maximum specific growth rate (µXr, and, consequently, a maximum specific oxygen uptake rate (QO2, in addition to significant residual biomass (Xr growth in high cell density cultures. In this context, this work investigated the strategy for obtaining high cell density, with the inclusion of a linear growth phase for P(3HB production by C. necator in a fed-batch culture. The linear growth phase was included between the exponential growth phase and the P(3HB production phase as a strategy to reduce the specific growth rate (µXr and specific oxygen uptake rate (QO2, with constant residual biomass growth rate (d(V.Xr/dt = k = constant and linear increase of biomass. Three strategies of culture were performed. The results showed that a high residual biomass concentration (30 gXr.L-1 can be reached by the inclusion of the linear growth strategy and specific growth rates (µXr between 0.08 and 0.05 h-1, at the beginning of the production phase, are necessary to attain a high P(3HB productivity.

  9. Thermal degradation kinetics and isoconversional analysis of biodegradable poly(3-hydroxybutyrate)/organomodified montmorillonite nanocomposites

    International Nuclear Information System (INIS)

    Achilias, Dimitris S.; Panayotidou, Elpiniki; Zuburtikudis, Ioannis

    2011-01-01

    Poly(3-hydroxybutyrate) (PHB)/organically modified clay nanocomposites were prepared by the melt mixing method and were characterized using wide-angle X-ray diffraction. Their thermal degradation kinetics was investigated using thermogravimetric analysis at various heating rates. Further kinetic analysis was performed using isoconversional methods and the invariant kinetic parameters method was used to estimate the so-called 'true' kinetic parameters, i.e. the pre-exponential factor, A and the activation energy, E, as well as the reaction model. It was found that intercalated structures are formed and the thermal stability of the material is improved by the addition of the nano-filler. From the isoconversional analysis, it was found that the activation energy does not vary significantly with the degree of degradation denoting degradation in one step with similar values for pure PHB and for all nanocomposites. Using the invariant kinetic parameters method, it was found that the model that best describes the experimental data was that of Sestak-Berggren's with f(a) = α n (1 - α) m , where the value of n is always larger than m and is increasing with the amount of the nano-filler. The value of the 'true' activation energy was found to be about 100 kJ mol -1 for all nanocomposites and the pre-exponential factor for PHB was estimated equal to 5.35 x 10 9 min -1 . Finally, the values of the kinetic rate constant k were found to decrease with the amount of the nano-filler up to 3 wt%, while for amounts larger than 3 wt% k increased reaching a value greater than that of pure PHB for the 10 wt% nanocomposites.

  10. Metabolic pathway for poly(3-hydroxybutyrate-co-3-hydroxyvalerate) formation in Nocardia corallina: inactivation of mutB by chromosomal integration of a kanamycin resistance gene.

    Science.gov (United States)

    Valentin, H F; Dennis, D

    1996-02-01

    The gene encoding the large subunit of the methylmalonyl-coenzyme A (CoA) mutase in Nocardia corallina (mutBNc) was cloned. A 4.3-kbp BamHI fragment containing almost the entire mutBNc was identified by Southern hybridization experiments employing a digoxigenin-labeled probe deduced from mutB of Streptomyces cinnamonensis, mutBNc was interrupted by insertion of a kanamycin resistance gene block (mutB::kan or mutB::neo) and introduced into N. corallina to obtain mutB-negative strains by homologous recombination. Four of sixteen kanamycin-resistant clones occurred via double-crossover events and harbored only the interrupted mutBNc. These exhibited no growth on odd-chain fatty acids in the presence of kanamycin but exhibited wild-type growth on even-chain fatty acids, glucose, and succinate. Whereas the wild type of N. corallina accumulates a copolyester of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) containing more than 60 mol% 3HV from most carbon sources, mutB-negative strains accumulated poly(3HB-co-3HV) containing only 2 to 6 mol% 3HV. Methylmalonyl-CoA mutase activity was not found in these clones. Therefore, this study provides strong evidence that the majority of 3HV units in poly(3HB-co-3HV) accumulated by N. corallina are synthesized via the methylmalonyl-CoA pathway.

  11. Sick day management using blood 3-hydroxybutyrate (3-OHB) compared with urine ketone monitoring reduces hospital visits in young people with T1DM: a randomized clinical trial.

    Science.gov (United States)

    Laffel, L M B; Wentzell, K; Loughlin, C; Tovar, A; Moltz, K; Brink, S

    2006-03-01

    Diabetic ketoacidosis (DKA), a life-threatening acute complication of Type 1 diabetes, may be preventable with frequent monitoring of glycaemia and ketosis along with timely supplemental insulin. This prospective, two-centre study assessed sick day management using blood 3-hydroxybutyrate (3-OHB) monitoring compared with traditional urine ketone testing, aimed at averting emergency assessment and hospitalization. One hundred and twenty-three children, adolescents and young adults, aged 3-22 years, and their families received sick day education. Participants were randomized to receive either a blood glucose monitor that also measures blood 3-OHB (blood ketone group, n = 62) or a monitor plus urine ketone strips (urine ketone group, n = 61). All were encouraged to check glucose levels > or = 3 times daily and to check ketones during acute illness or stress, when glucose levels were consistently elevated (> or = 13.9 mmol/l on two consecutive readings), or when symptoms of DKA were present. Frequency of sick days, hyperglycaemia, ketosis, and hospitalization/emergency assessment were ascertained prospectively for 6 months. There were 578 sick days during 21,548 days of follow-up. Participants in the blood ketone group checked ketones significantly more during sick days (276 of 304 episodes, 90.8%) than participants in the urine ketone group (168 of 274 episodes, 61.3%) (P ketone group (38/100 patient-years) compared with the urine ketone group (75/100 patient-years) (P = 0.05). Blood ketone monitoring during sick days appears acceptable to and preferred by young people with Type 1 diabetes. Routine implementation of blood 3-OHB monitoring for the management of sick days and impending DKA can potentially reduce hospitalization/emergency assessment compared with urine ketone testing and offers potential cost savings.

  12. Polyhydroxyalkanoate production from crude glycerol by newly isolated Pandoraea sp.

    Directory of Open Access Journals (Sweden)

    Fabrício Coutinho de Paula

    2017-04-01

    Full Text Available A new bacterial strain was isolated from Atlantic rainforest in Brazil for polyhydroxyalkanoate (PHA production utilizing crude glycerol from biodiesel industry (CG and it was identified as Pandoraea sp. MA03. Shake flask experiments were performed at 10–50 g L−1 carbon source and showed the best values of poly(3-hydroxybutyrate (P3HB production from CG cultivations compared to pure glycerol, with a polymer accumulation ranging from 49.0% to 63.6% cell dry weight (CDW. The results obtained from this study showed a positive effect of contaminant NaCl on P3HB synthesis up to 30 g L−1 CG. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate [P(3HB-co-3HV] production was obtained from CG plus propionic acid with up to 25.9 mol% 3HV. Since it is interesting the utilization of CG for obtaining added-value products along with biodiesel, this study reported a novel and promising PHA-producing bacterial strain as an additional effort to enhance the viability of a sustainable industry based on biofuels and biopolymers.

  13. Analysis of the structure of poly-3-hydroxybutyrate ultrathin fibers modified with iron (III) complex with tetraphenylporphyrin

    Science.gov (United States)

    Olkhov, A. A.; Karpova, S. G.; Lobanov, A. V.; Tyubaeva, P. M.; Artemov, N. S.; Iordansky, A. L.

    2017-12-01

    In the treatment of many infectious diseases and cancer, transdermal systems based on solid polymer matrices or gels containing functional substances with antiseptic (antibacterial) properties are often used. One of the most promising types of matrices with antiseptic properties are the ones of nano- and microfiber-bonded cloth obtained by electrospinning based on biopolymer poly(3-hydroxybutyrate). The present work investigates the effects of iron (III) complex with tetraphenylporphyrin and the influence on the geometry, crystalline order and molecular dynamics in the intercrystalline (amorphous phase) of ultrathin PHB fibers.

  14. Enhancement of ε-poly-L-lysine production coupled with precursor L-lysine feeding in glucose-glycerol co-fermentation by Streptomyces sp. M-Z18.

    Science.gov (United States)

    Chen, Xu-Sheng; Ren, Xi-Dong; Zeng, Xin; Zhao, Fu-Lin; Tang, Lei; Zhang, Hong-Jian; Zhang, Jian-Hua; Mao, Zhong-Gui

    2013-12-01

    ε-Poly-L-lysine (ε-PL), one of the only two homo-poly amino acids known in nature, is used as a preservative. In this study, strategies of feeding precursor L-lysine into 5 L laboratory scale fermenters, including optimization of L-lysine concentration and time, was investigated to optimize the production of ε-PL by Streptomyces sp. M-Z18. The optimized strategy was then used in ε-PL fed-batch fermentation in which glucose and glycerol served as mixed carbon sources. In this way, a novel ε-PL production strategy involving precursor L-lysine coupled with glucose-glycerol co-fermentation was developed. Under optimal conditions, ε-PL production reached 37.6 g/l, which was 6.2 % greater than in a previous study in which glucose and glycerol co-fermentation was performed without added L-lysine (35.14 g/l). To the best of our knowledge, this is the first report of the enhancement of ε-PL production through L-lysine feeding to evaluate the use of fermenters. Meanwhile, the role of L-lysine in the promotion of ε-PL production, participating ε-PL synthesis as a whole, was first determined using the L-[U-(13)C] lysine labeling method. It has been suggested that the bottleneck of ε-PL synthesis in Streptomyces sp. M-Z18 is in the biosynthesis of precursor L-lysine. The information obtained in the present work may facilitate strain improvement and efficient large-scale ε-PL production.

  15. Oxidation of glycerol by Streptococcus faecalis.

    Science.gov (United States)

    CLARIDGE, C A; HENDLIN, D

    1962-12-01

    Claridge, C. A. (Merck Sharp & Dohme Research Laboratories, Rahway, N.J.) and David Hendlin. Oxidation of glycerol by Streptococcus faecalis. J. Bacteriol. 84:1181-1186. 1962.-The nature of the factors in yeast autolysate essential for the oxidation of glycerol by Streptococcus faecalis F24 was examined. Two factors appear to be involved in the oxidation of glycerol. One factor was shown to be an inducer of the enzyme system required for glycerol oxidation; the other was shown to be alpha-lipoic acid. Minute quantities of glucose will "spark" growth of S. faecalis in a medium containing glycerol and acetate as carbon sources, probably by supplying sufficient energy for induction of the glycerol-oxidation system.

  16. Design and analysis of biorefineries based on raw glycerol: addressing the glycerol problem.

    Science.gov (United States)

    Posada, John A; Rincón, Luis E; Cardona, Carlos A

    2012-05-01

    Glycerol as a low-cost by-product of the biodiesel industry can be considered a renewable building block for biorefineries. In this work, the conversion of raw glycerol to nine added-value products obtained by chemical (syn-gas, acrolein, and 1,2-propanediol) or bio-chemical (ethanol, 1,3-propanediol, d-lactic acid, succinic acid, propionic acid, and poly-3-hydroxybutyrate) routes were considered. The technological schemes for these synthesis routes were designed, simulated, and economically assessed using Aspen Plus and Aspen Icarus Process Evaluator, respectively. The techno-economic potential of a glycerol-based biorefinery system for the production of fuels, chemicals, and plastics was analyzed using the commercial Commercial Sale Price/Production Cost ratio criteria, under different production scenarios. More income can be earned from 1,3-propanediol and 1,2-propanediol production, while less income would be obtained from hydrogen and succinic acid. This analysis may be useful mainly for biodiesel producers since several profitable alternatives are presented and discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Direct Production of (R)-3-Hydroxybutyric Acid of High Optical Purity by Halomonas sp. OITC1261 Under Aerobic conditions.

    Science.gov (United States)

    Yokaryo, Hiroto; Teruya, Morimi; Hanashiro, Ryuji; Goda, Masahiro; Tokiwa, Yutaka

    2018-02-01

    The chiral compound (R)-3-hydroxybutyric acid (R-3HB) has some important physiological functions in the human body and can also be applied as a functional material for industrial products. A novel Halomonas sp. OITC1261 isolated from a coastal sediment is selected for efficient production of R-3HB. This strain secreted R-3HB of high optical purity into the extracellular medium while maintaining poly(3-hydroxybutyric acid) (PHB) inside the microbial cell under aerobic conditions. There is a possibility that R-3HB is generated independently of PHB. Under aerobic cultivation, 58 g L -1 (0.65 g L -1  h -1 ) of R-3HB was produced simultaneously with 27 g L -1 (0.30 g L -1  h -1 ) of PHB. This direct production method of R-3HB contributes to the improvement of mass production technology. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Isomerization of 1-O-indol-3-ylacetyl-beta-D-glucose. Enzymatic hydrolysis of 1-O, 4-O, and 6-O-indol-3-ylacetyl-beta-D-glucose and the enzymatic synthesis of indole-3-acetyl glycerol by a hormone metabolizing complex

    Science.gov (United States)

    Kowalczyk, S.; Bandurski, R. S.

    1990-01-01

    The first compound in the series of reactions leading to the ester conjugates of indole-3-acetic acid (IAA) in kernels of Zea mays sweet corn is the acyl alkyl acetal, 1-O-indol-3-ylacetyl-beta-D-glucose (1-O-IAGlu). The enzyme catalyzing the synthesis of this compound is UDP-glucose:indol-3-ylacetate glucosyl-transferase (IAGlu synthase). The IAA moiety of the high energy compound 1-O-IAGlu may be enzymatically transferred to myo-inositol or to glycerol or the 1-O-IAGlu may be enzymatically hydrolyzed. Alternatively, nonenzymatic acyl migration may occur to yield the 2-O, 4-O, and 6-O esters of IAA and glucose. The 4-O and 6-O esters may then be enzymatically hydrolyzed to yield free IAA and glucose. This work reports new enzymatic activities, the transfer of IAA from 1-O-IAGlu to glycerol, and the enzyme-catalyzed hydrolysis of 4-O and 6-O-IAGlu. Data is also presented on the rate of non-enzymatic acyl migration of IAA from the 1-O to the 4-O and 6-O positions of glucose. We also report that enzymes catalyzing the synthesis of 1-O-IAGlu and the hydrolysis of 1-O, 4-O, and 6-O-IAGlu fractionate as a hormone metabolizing complex. The association of synthetic and hydrolytic capabilities in enzymes which cofractionate may have physiological significance.

  19. Multiple propionyl coenzyme A-supplying pathways for production of the bioplastic poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in Haloferax mediterranei.

    Science.gov (United States)

    Han, Jing; Hou, Jing; Zhang, Fan; Ai, Guomin; Li, Ming; Cai, Shuangfeng; Liu, Hailong; Wang, Lei; Wang, Zejian; Zhang, Siliang; Cai, Lei; Zhao, Dahe; Zhou, Jian; Xiang, Hua

    2013-05-01

    Haloferax mediterranei is able to accumulate the bioplastic poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with more than 10 mol% 3-hydroxyvalerate (3HV) from unrelated carbon sources. However, the pathways that produce propionyl coenzyme A (propionyl-CoA), an important precursor of 3HV monomer, have not yet been determined. Bioinformatic analysis of H. mediterranei genome indicated that this strain uses multiple pathways for propionyl-CoA biosynthesis, including the citramalate/2-oxobutyrate pathway, the aspartate/2-oxobutyrate pathway, the methylmalonyl-CoA pathway, and a novel 3-hydroxypropionate pathway. Cofeeding of pathway intermediates and inactivating pathway-specific genes supported that these four pathways were indeed involved in the biosynthesis of 3HV monomer. The novel 3-hydroxypropionate pathway that couples CO2 assimilation with PHBV biosynthesis was further confirmed by analysis of (13)C positional enrichment in 3HV. Notably, (13)C metabolic flux analysis showed that the citramalate/2-oxobutyrate pathway (53.0% flux) and the 3-hydroxypropionate pathway (30.6% flux) were the two main generators of propionyl-CoA from glucose. In addition, genetic perturbation on the transcriptome of the ΔphaEC mutant (deficient in PHBV accumulation) revealed that a considerable number of genes in the four propionyl-CoA synthetic pathways were significantly downregulated. We determined for the first time four propionyl-CoA-supplying pathways for PHBV production in haloarchaea, particularly including a new 3-hydroxypropionate pathway. These results would provide novel strategies for the production of PHBV with controllable 3HV molar fraction.

  20. Influence of gamma radiation on thermal properties and water vapor transmission of poly(3-hydroxybutyrate) (PHB) in blends

    International Nuclear Information System (INIS)

    Forster, Pedro L.; Martins, Natalia A.; Parra, Duclerc F.; Egute, Nayara S.; Lugao, Ademar B.

    2009-01-01

    Biodegradable polymers are a newly emerging field. A vast number of biodegradable polymers have been synthesized recently and some microorganisms and enzymes capable of degrading them have been identified. Polyesters such as poly(3-hydroxybutyrate) (PHB) or other polyhydroxyalkanoates (PHAs) have attracted commercial and academic interest as new biodegradable materials. In this work, we investigated the effect of gamma radiation on the thermal properties and biodegradation behavior of PHB in blend with poly(ethyleneglycol)(PEG). The samples were irradiated at gamma radiation of 5 and 10 kGy. The thermal behaviour was investigated by utilization of differential scanning calorimetry (DSC) changes in thermal stability, glass transition and melting point were reported. (author)

  1. A simple and efficient method for poly-3-hydroxybutyrate quantification in diazotrophic bacteria within 5 minutes using flow cytometry

    Directory of Open Access Journals (Sweden)

    L.P.S. Alves

    Full Text Available The conventional method for quantification of polyhydroxyalkanoates based on whole-cell methanolysis and gas chromatography (GC is laborious and time-consuming. In this work, a method based on flow cytometry of Nile red stained bacterial cells was established to quantify poly-3-hydroxybutyrate (PHB production by the diazotrophic and plant-associated bacteria, Herbaspirillum seropedicae and Azospirillum brasilense. The method consists of three steps: i cell permeabilization, ii Nile red staining, and iii analysis by flow cytometry. The method was optimized step-by-step and can be carried out in less than 5 min. The final results indicated a high correlation coefficient (R2=0.99 compared to a standard method based on methanolysis and GC. This method was successfully applied to the quantification of PHB in epiphytic bacteria isolated from rice roots.

  2. A simple and efficient method for poly-3-hydroxybutyrate quantification in diazotrophic bacteria within 5 minutes using flow cytometry

    Science.gov (United States)

    Alves, L.P.S.; Almeida, A.T.; Cruz, L.M.; Pedrosa, F.O.; de Souza, E.M.; Chubatsu, L.S.; Müller-Santos, M.; Valdameri, G.

    2017-01-01

    The conventional method for quantification of polyhydroxyalkanoates based on whole-cell methanolysis and gas chromatography (GC) is laborious and time-consuming. In this work, a method based on flow cytometry of Nile red stained bacterial cells was established to quantify poly-3-hydroxybutyrate (PHB) production by the diazotrophic and plant-associated bacteria, Herbaspirillum seropedicae and Azospirillum brasilense. The method consists of three steps: i) cell permeabilization, ii) Nile red staining, and iii) analysis by flow cytometry. The method was optimized step-by-step and can be carried out in less than 5 min. The final results indicated a high correlation coefficient (R2=0.99) compared to a standard method based on methanolysis and GC. This method was successfully applied to the quantification of PHB in epiphytic bacteria isolated from rice roots. PMID:28099582

  3. Photoacoustic Monitoring of Internal Plastification in Poly(3-hydroxybutyrate-co-3-hydroxyvalerate Copolymers: Measurements of Thermal Parameters

    Directory of Open Access Journals (Sweden)

    Sanchez Ruben R.

    1999-01-01

    Full Text Available Basic data on thermophysical properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate copolymers poly(3HB-co-3HV were investigated with the aim of understanding the role of 3-hydroxyvalerate monomeric units (3HV incorporated during random copolymerization. The results show strong evidence that internal plastification is produced by the introduction of 3HV units in the copolymer. It was observed that copolymer thermal conductivity increased approximately linearly with the 3HV content. On the other hand, thermal diffusivity was very sensitive to the change in the copolymer composition showing a sudden rise that attained a saturation plateau. Amplitude-frequency plots indicate that a thermoelastic bending mechanism is operating. In this paper a new photoacoustic arrangement for the measurement of thermal effusivity is presented.

  4. Fabrication of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) biocomposites with reinforcement by hydroxyapatite using extrusion processing.

    Science.gov (United States)

    Öner, Mualla; İlhan, Berna

    2016-08-01

    The aim of this study was to prepare poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV, biocomposites with incorporating various percentages of hydroxyapatite (HAP) using extrusion processing. The biocomposites were produced by melt extrusion of PHBV with untreated HAP and surface-treated HAP crystals. The structure of biopolymer/HAP biocomposites was investigated by XRD, FTIR, DSC and SEM. Silane coupling agent was used for HAP surface treatment in PHBV/HAP composites. Silane-treated HAP nanoparticles yielded nanocomposites characterized by good mechanical performance and fine nanofiller dispersion, as shown by SEM investigations. The Halpin-Tsai and Hui-Shia models were used to evaluate the effect of reinforcement by HAP particles on the elastic modulus of the composites. Micromechanical models for initial composite stiffness showed good correlation with experimental values. Disparities in the Halpin-Tsai model were evident for composite with higher HAP loadings. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Poly(3-hydroxybutyrate) and Eudragit E microparticles: a release system to enhance the aqueous solubility of felodipine and simvastatin

    International Nuclear Information System (INIS)

    Bazzo, Giovana C.; Pezzini, Bianca R.; Zetola, Melissa; Wagner, Theodoro M.; Caetano, Daniela B.; Boch, Maura; Schmucker, Iara C.; Schucko, Sacha K.

    2009-01-01

    Poor water-soluble drugs are a problem for the development of oral solid dosage forms, since it has great potential for low bioavailability. Thus, release systems that promote the increase of aqueous solubility of these drugs are advantageous. This study aimed to evaluate the feasibility of incorporation of felodipine and simvastatin in polymeric microparticles, to improve the aqueous solubility of the drugs. Microparticles of poly(3-hydroxybutyrate) [PHB] and Eudragit E was prepared by emulsion - solvent evaporation technique and characterized as to morphology and encapsulation efficiency of the drugs. Particles with spherical shapes and high levels of drug encapsulated were obtained. There was a significant increase in aqueous solubility of felodipine and simvastatin after its incorporation into the polymeric microparticles. X-ray diffraction analysis showed the conversion of both drugs to amorphous form, which may have contributed to increased the solubility. (author)

  6. Unusual ``Twisting'' Morphology in Poly(3-hydroxybutyrate-co 3-hydroxyhexanoate) and Poly(bisphenol A hexane ether) Spherulites

    Science.gov (United States)

    Schultz, Jerold

    2013-03-01

    Polarized light images of poly(3- hydroxybutyrate-co 3-hydroxyhexanoate) spherulites grown from the melt exhibit the standard evidence of periodic twisting of lamellae. AFM images of lamellae growing from the melt, on the other hand, reveal a sudden change in orientation and a trowel-like morphology. Similarly, AFM images of poly(bisphenol A hexane ether) (BA-C6) lamellae growing from the melt show a sudden orthogonal change of orientation. It is suggested that chain extension in the melt near the propagating front forces the observed reorientation, possibly through creation of crystals with an orientation approximately orthogonal to that of the original crystals. A rudimentary model for this behavior is proposed.

  7. Surface wettability and energy effects on the biological performance of poly-3-hydroxybutyrate films treated with RF plasma

    Energy Technology Data Exchange (ETDEWEB)

    Syromotina, D.S. [Department of Experimental Physics, National Research Tomsk Polytechnic University, 634050 Tomsk (Russian Federation); Surmenev, R.A., E-mail: rsurmenev@gmail.com [Department of Experimental Physics, National Research Tomsk Polytechnic University, 634050 Tomsk (Russian Federation); Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, 70569 Stuttgart (Germany); Surmeneva, M.A. [Department of Experimental Physics, National Research Tomsk Polytechnic University, 634050 Tomsk (Russian Federation); Boyandin, A.N.; Nikolaeva, E.D. [Institute of Biophysics of Siberian Branch of Russian Academy of Sciences, 50/50 Akademgorodok, Krasnoyarsk 660036 (Russian Federation); School of Fundamental Biology and Biotechnology, Siberian Federal University, 79 Svobodny pr., 660041 Krasnoyarsk (Russian Federation); Prymak, O.; Epple, M. [Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, 45117 Essen (Germany); Ulbricht, M. [Technical Chemistry II and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, 45141 Essen (Germany); Oehr, C. [Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, 70569 Stuttgart (Germany); Volova, T.G. [Institute of Biophysics of Siberian Branch of Russian Academy of Sciences, 50/50 Akademgorodok, Krasnoyarsk 660036 (Russian Federation); School of Fundamental Biology and Biotechnology, Siberian Federal University, 79 Svobodny pr., 660041 Krasnoyarsk (Russian Federation)

    2016-05-01

    The surface properties of poly-3-hydroxybutyrate (P3HB) membranes were modified using oxygen and an ammonia radio-frequency (RF, 13.56 MHz) plasma. The plasma treatment procedures used in the study only affected the surface properties, including surface topography, without inducing any significant changes in the crystalline structure of the polymer, with the exception being a power level of 250 W. The wettability of the modified P3HB surfaces was significantly increased after the plasma treatment, irrespective of the treatment procedure used. It was revealed that both surface chemistry and surface roughness changes caused by the plasma treatment affected surface wettability. A treatment-induced surface aging effect was observed and resulted in an increase in the water contact angle and a decrease in the surface free energy. However, the difference in the water contact angle between the polymers that had been treated for 4 weeks and the untreated polymer surfaces was still significant. A dependence between cell adhesion and proliferation and the polar component of the surface energy was revealed. The increase in the polar component after the ammonia plasma modification significantly increased cell adhesion and proliferation on biodegradable polymer surfaces compared to the untreated P3HB and the P3HB modified using an oxygen plasma. - Highlights: • Plasma treatment affected the topography of poly(3-hydroxybutyrate) (P3HB). • Plasma treatment resulted in improvement of the surface wettability. • No alteration of the bulk properties of the polymers was observed. • The ammonia plasma treatment at 150 W improved the cell adhesion and proliferation.

  8. Microbial recycling of glycerol to biodiesel.

    Science.gov (United States)

    Yang, Liu; Zhu, Zhi; Wang, Weihua; Lu, Xuefeng

    2013-12-01

    The sustainable supply of lipids is the bottleneck for current biodiesel production. Here microbial recycling of glycerol, byproduct of biodiesel production to biodiesel in engineered Escherichia coli strains was reported. The KC3 strain with capability of producing fatty acid ethyl esters (FAEEs) from glucose was used as a starting strain to optimize fermentation conditions when using glycerol as sole carbon source. The YL15 strain overexpressing double copies of atfA gene displayed 1.7-fold increase of FAEE productivity compared to the KC3 strain. The titer of FAEE in YL15 strain reached to 813 mg L(-1) in minimum medium using glycerol as sole carbon source under optimized fermentation conditions. The titer of glycerol-based FAEE production can be significantly increased by both genetic modifications and fermentation optimization. Microbial recycling of glycerol to biodiesel expands carbon sources for biodiesel production. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Poly(3-hydroxybutyrate-co-R-3-hydroxyhexanoate) nanoparticles with polyethylenimine coat as simple, safe, and versatile vehicles for cell targeting

    DEFF Research Database (Denmark)

    Wu, Linping; Wang, Danyang; Parhamifar, Ladan

    2014-01-01

    A simple and highly safe poly(3-hydroxybutyrate-co-R-3-hydroxyhexanoate) nanoparticulate delivery system that targets different cell types is developed. A sub-cytotoxic level of polyethylenimine coat mediates universal cell targeting. Internalized nanoparticles traffic along endolysosomal compart...

  10. 3D FT-IR imaging spectroscopy of phase-separation in a poly(3-hydroxybutyrate)/poly(L-lactic acid) blend

    Science.gov (United States)

    Miriam Unger; Julia Sedlmair; Heinz W. Siesler; Carol Hirschmugl; Barbara Illman

    2014-01-01

    In the present study, 3D FT-IR spectroscopic imaging measurements were applied to study the phase separation of a poly(3-hydroxybutyrate) (PHB)/poly(L-lactic acid) (PLA) (50:50 wt.%) polymer blend film. While in 2D projection imaging the z-dependent information is overlapped, thereby complicating the analysis, FT-IR spectro-micro-tomography,...

  11. Composite scaffolds for cartilage tissue engineering based on natural polymers of bacterial origin, thermoplastic poly(3-hydroxybutyrate) and micro-fibrillated bacterial cellulose

    Czech Academy of Sciences Publication Activity Database

    Akaraonye, E.; Filip, J.; Šafaříková, Miroslava; Salih, V.; Keshavarz, T.; Knowles, J.C.; Roy, I.

    2016-01-01

    Roč. 65, č. 7 (2016), s. 780-791 ISSN 0959-8103 Institutional support: RVO:60077344 Keywords : polyhydroxyalkanoates * poly(3-hydroxybutyrate) * bacterial cellulose * micro-fibrillated cellulose * tissue engineering scaffold * composite materials Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.070, year: 2016

  12. Synthesis, characterizations and biocompatibility of novel biodegradable star block copolymers based on poly[(R)-3-hydroxybutyrate] and poly(epsilon-caprolactone)

    DEFF Research Database (Denmark)

    Wu, Linping; Wang, Liang; Wang, Xiaojuan

    2010-01-01

    Star block copolymers based on poly[(R)-3-hydroxybutyrate] (PHB) and poly(epsilon-caprolactone) (PCL), termed SPHBCL, were successfully synthesized with structural variation on arm numbers and lengths via coupling reactions and ring opening polymerizations. Arm numbers 3, 4 and 6 of SPHBCL were s...

  13. Study on the Effect of Levulinic Acid on Whey-Based Biosynthesis of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate by Hydrogenophaga pseudoflava

    Directory of Open Access Journals (Sweden)

    Martin Koller

    2017-04-01

    Full Text Available Background and Objective: Production of polyhydroxyalkanoate copolyesters consisting of 3-hydroxybutyrate and 3-hydroxyvalerate units was for the first time studied using the production strain Hydrogenophaga pseudoflava based on sustainable raw materials. This strategy provides for increased cost efficiency in PHA production and in enhanced material quality.Material and Methods: As a particularity, production of these poly(3-hydroxybutyrate-co-3- hydroxyvalerate copolyesters was based on a novel substrate/co-substrate combination: whey permeate from dairy industry, on the one hand, acted as substrate for biomass and 3HB biosynthesis; on the other hand, levulinic acid, accessible from various renewable resources, was used as 3HV-related precursor compound. The experiments were carried out on shaking flask scale using defined nutrient media.Results and Conclusion: Applied during nutritionally balanced growth of H. pseudoflava, levulinicacid displays drastic growth inhibition at rather low concentrations of 0.2 g l-1 (growth inhibition constant Ki = 0.032, which suggests the careful supply of this compound in the first phase of cultivation. Under nitrogen-free cultivation conditions, inhibition of the strain´s metabolism by levulinic acid was less pronounced. Here, poly(3-hydroxybutyrate-co- 3-hydroxyvalerate concentrations up to 4.2 g l-1 and volumetric poly(3-hydroxybutyrate-co-3- hydroxyvalerate productivities up to 0.06 g l-1 h -1 were achieved in dependence on the precursor supply. Investigating poly(3-hydroxybutyrate-co-3-hydroxyvalerate composition in setups supplied with differently composed whey/levulinic acid mixtures revealed 3- hydroxyvalerate fractions in the polymer between 0 and 0.6 mol mol-1 . This study successfully demonstrates the feasibility of combined utilization of different waste- and by-products from food industry and agriculture for generation of value-added 2nd generation biopolymers. Conflict of interest: The authors

  14. Poly(3-hydroxybutyrate-co-epsilon-caprolactone) copolymers and poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-epsilon-caprolactone) terpolymers as novel materials for colloidal drug delivery systems.

    Science.gov (United States)

    Pignatello, Rosario; Musumeci, Teresa; Impallomeni, Giuseppe; Carnemolla, Giovanni Marco; Puglisi, Giovanni; Ballistreri, Alberto

    2009-06-28

    Poly(3-hydroxybutyrate-co-epsilon-caprolactone) copolymers and poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-epsilon-caprolactone) terpolymers were used by a solvent deposition technique to prepare either micro- or nanoparticles. In particular, the synthesis and analytical characterization of the terpolymers were described.On the basis of copolymer composition and properties, either micro- or nanoparticles were obtained; nanoparticle size was below 500 nm for the suspensions obtained from P(HB-co-CL) copolymers, and even smaller (200-300 nm) for those obtained using terpolymers. Particle size showed only a limited tendency to increase during storage, suggesting a good chemical and physical stability in the short-term storage at room temperature. Some copolymers produced hetero-dispersed microparticles under the same conditions, with a mean size between 10 and 30 microm. These systems showed a tendency to aggregate upon storage at room temperature.The nanoparticles showed a negative surface charge (around -20 mV for those prepared using an UltraTurrax and about -5 mV for those prepared by magnetic stirring). After storage at 4 degrees C the surface charge tend to decrease and these changes have been explained in terms of a partial hydrolysis of the polymeric matrix in aqueous suspension, which led to a change of chemical composition at the surface of the particles.The fluorescent probes calcein and Oil Red O were encapsulated in these systems as models of a hydrophilic and lipophilic drug molecule, respectively. Encapsulation efficiency and in vitro release profiles were studied to evaluate the effect of copolymer properties, such as molecular weight and composition, on their behaviour as potential materials to prepare controlled drug delivery carriers. Calcein was generally better encapsulated (up to 100%) than Oil Red O (10-30%); however, the zeta-potential measurement and in vitro release experiments suggested that a large amount of calcein was adsorbed onto the

  15. Growth and energy metabolism of Nile tilapia juveniles fed glycerol

    Directory of Open Access Journals (Sweden)

    Diego Vicente da Costa

    2015-05-01

    Full Text Available The objective of this work was to evaluate the effect of inclusion of dietary glycerol in replacement to starch on the growth and energy metabolism of Nile tilapia juveniles. The experiment was carried out in a completely randomized design with four treatments (0, 5, 10, and 15% purified glycerol and six replicates. Pelleted, isonitrogenous, and isocaloric diets were provided for 60 days. Growth performance parameters and muscle glucose and protein concentrations were not affected by dietary glycerol levels. The treatment with 15% glycerol presented higher levels of muscle and liver triglycerides. A quadratic effect of treatments on muscle and liver triglyceride concentrations was observed. The treatment with 0% glycerol presented higher hepatic glucose levels than the one with 15%. Treatments did not differ for concentrations of liver protein, as well as of plasma glucose, triglycerides, and protein. Treatments with 10 and 15% glycerol showed higher activity of the glucose-6-phosphate-dehydrogenase enzyme than the treatment with 5%; however, there were no significant differences in the hepatic activities of the malic and glycerol kinase enzymes. A linear positive effect of treatments was observed on the activity of the glycerol kinase enzyme in liver. Levels of glycerol inclusion above 10% in the diet of Nile tilapia juveniles characterize it as a lipogenic nutrient.

  16. Production and Characterization of Poly(3-Hydroxybutyrate from Oleic Acid by Ralstonia eutropha

    Directory of Open Access Journals (Sweden)

    Vitor Henrique Grigull

    2008-01-01

    Full Text Available The aim of this research is to investigate the influence of oleic acid concentration on the cell growth and the physical properties of the polymer formed by cultures of Ralstonia eutropha in mineral medium. Cells were cultivated in Erlenmeyer flasks with 300 mL of mineral medium, containing glucose and fructose as a carbon source (30 g/L and ammonium sulphate (5.0 g/L as a nitrogen source. Oleic acid was added as nutritional supplement in different concentrations (0, 0.3, 0.9, 1.5 and 3.0 g/L and the cells were incubated at 30 °C and 150 rpm. The films prepared by casting were evaluated by X-ray diffraction, thermogravimetry and differential scanning calorimetry. These results indicate that the increase of oleic acid concentrations leads to a higher specific growth rate and cell productivity. The characterization of the films revealed that the increase of the concentration of oleic acid from 0 to 1.5 g/L has no influence on thermal behaviour and crystallinity degree. However, the thermal stability, melting temperature, glass transition temperatures and crystallinity degree decreased when 3.0 g/L of oleic acid were used.

  17. UNIQUAC interaction parameters for molecules with -OH groups on adjacent carbon atoms in aqueous solution determined by molecular mechanics - glycols, glycerol and glucose

    DEFF Research Database (Denmark)

    Jonsdottir, Svava Osk; Klein, R. A.

    1997-01-01

    Procedure (BJP).The predicted vapor-liquid-equilibrium (VLE) data for the water/1,2-ethanediol system are in excellent agreement with the experimentalvalues and good results were obtained for the water/glycerol system by taking larger samples. This was not true for the other two systemsfor which there were...... difficulties in sampling conformational space in a statistically acceptable manner. As the parameters representinteractions per unit molecular surface area and all of the molecules consist of -CH2OH or -CH2O- units, the values obtained for thewater/1,2-ethanediol system were used to predict VLE data...... for the other systems. This gave results in good agreement with the experimental data.The possibility of transferring interaction parameters is very interesting,especially as it can be applied to systems for which the additivity principle of the UNIFAC method fails.Simulations were carried out for 1...

  18. Two-stage (photoautotrophy and heterotrophy) cultivation enables efficient production of bioplastic poly-3-hydroxybutyrate in auto-sedimenting cyanobacterium.

    Science.gov (United States)

    Monshupanee, Tanakarn; Nimdach, Palida; Incharoensakdi, Aran

    2016-11-15

    Sustainable production of bioplastics by heterotrophic microbes has been restricted by the limited resources of organic substrates and the energy required for biomass harvest. Here, the easy-to-harvest cyanobacterium (Chlorogloea fritschii TISTR 8527), from which the biomass instantaneously settled to the bottom of liquid culture, was utilized to produce poly-3-hydroxybutyrate (PHB) using a two-stage cultivation strategy. The cells were first pre-grown under normal photoautotrophy to increase their biomass and then recultivated under a heterotrophic condition with a single organic substrate to produce the product. Through optimization of this two-stage cultivation, the mass conversion efficiency of acetate substrate to PHB was obtained at 51 ± 7% (w/w), the comparable level to the theoretical biochemical conversion efficiency of acetate to PHB. This two-stage cultivation that efficiently converted the substrate to the product, concurrent with a reduced culture biomass, may be applicable for the production of other biopolymers by cyanobacteria.

  19. Renewable resource-based green composites from recycled cellulose fiber and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) bioplastic.

    Science.gov (United States)

    Bhardwaj, Rahul; Mohanty, Amar K; Drzal, L T; Pourboghrat, F; Misra, M

    2006-06-01

    Novel "green" composites were successfully fabricated from recycled cellulose fibers (RCF) and a bacterial polyester, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) by melt mixing technique. Various weight contents (15%, 30%, and 40%) of the fibers were incorporated in the PHBV matrix. The effect of the fiber weight contents on the thermal, mechanical, and dynamic-mechanical thermal properties of PHBV was investigated and a comparative property analysis was performed with RCF-reinforced polypropylene (PP) composites. The tensile and storage moduli of the PHBV-based composites were improved by 220% and 190%, respectively, by reinforcement with 40 wt % RCF. Halpin-Tsai and Tsai-Pagano's equations were applied for the theoretical modeling of the tensile modulus of PHBV-based composites. The heat deflection temperature (HDT) of the PHBV-based composites was increased from 105 to 131 degrees C, while the coefficient of linear thermal expansion (CLTE) value was reduced by 70% upon reinforcement with 40 wt % RCF. The PHBV-based composites had also shown better tensile and storage moduli and lower CLTE values than PP-based composites. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to study the melting behavior, thermal stability, and morphology of the composite systems, respectively.

  20. Siliceous mesostructured cellular foams/poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) composite biomaterials for bone regeneration.

    Science.gov (United States)

    Yang, Shengbing; Xu, Shuogui; Zhou, Panyu; Wang, Jing; Tan, Honglue; Liu, Yang; Tang, TingTing; Liu, ChangSheng

    2014-01-01

    Osteoinductive and biodegradable composite biomaterials for bone regeneration were prepared by combining poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) with siliceous mesostructured cellular foams (SMC), using the porogen leaching method. Surface hydrophilicity, morphology, and recombinant human bone morphogenetic protein 2 adsorption/release behavior of the SMC/PHBHHx scaffolds were analyzed. Results of scanning electron microscopy indicated that the SMC was uniformly dispersed in the PHBHHx scaffolds, and SMC modification scaffolds have an interconnected porous architecture with pore sizes ranging from 200 to 400 μm. The measurements of the water contact angles suggested that the incorporation of SMC into PHBHHx improves the hydrophilicity of the composite. In vitro studies with simulated body fluid show great improvements to bioactivity and biodegradability versus pure PHBHHx scaffolds. Cell adhesion and cell proliferation on the scaffolds was also evaluated, and the new tools provide a better environment for human mesenchymal stem cell attachment, spreading, proliferation, and osteogenic differentiation on PHBHHx scaffolds. Moreover, micro-computed tomography and histological evaluation confirmed that the SMC/PHBHHx scaffolds improved the efficiency of new bone regeneration with excellent biocompatibility and biodegradability and faster and more effective osteogenesis in vivo.

  1. Mechanical and Morphological Properties of Poly-3-hydroxybutyrate/Poly(butyleneadipate-co-terephthalate/Layered Double Hydroxide Nanocomposites

    Directory of Open Access Journals (Sweden)

    Yen Leng Pak

    2013-01-01

    Full Text Available Nanocomposites of poly-3-hydroxybutyrate/poly(butyleneadipate-co-terephthalate/layered double hydroxide (PHB/PBAT/LDH were prepared from a binary blend of PHB/PBAT and stearate-Zn3Al LDH via a solution casting method using chloroform as solvent in this study. The pristine Zn3Al LDH was synthesized from nitrate salts solution at pH 7 by using coprecipitation technique and then was modified by stearate anions surfactant via ion exchange reaction. As a result, the basal spacing of the LDH was increased from 8.77 to 24.94 Å after the modification. Intercalated nanocomposites were formed due to the presence of diffraction peak in XRD diffractograms. The infrared spectrum of stearate-Zn3Al LDH exhibited the existence of stearate anions in the synthesized Zn3Al LDH. Mechanical properties with 2 wt% stearate-Zn3Al LDH loading nanocomposites showed 56 wt% improvements in elongation at break compared to those of the blend.

  2. Miscibility and Crystallization Behavior of Poly (3- Hydroxybutyrate) and Poly (Ethylene Glycol) Blends Studied by Positron Annihilation Spectroscopy

    International Nuclear Information System (INIS)

    Abdel-Hady, E.E.; Hammam, A.M.

    2010-01-01

    Poly (3-hydroxybutyrate) (PHB) is linear stereo regular aliphatic polyester synthesized by some bacteria as a store of carbon and energy. Because of its high biocompatibility and the ability to be fully biodegraded, PHB is of special interest in medicine. To improve the physiochemical properties of PHB, Polyethylene glycol (PEG) was used for modifications of PHB. By using the chloroform as co-solvent a series of (PHB/PEG) blend with different ratio ranging from 100:0.0 (wt %) to 50:50 (wt %) was prepared by solution casting-technique. Positron Annihilation Lifetime (PAL) technique has been applied to study the effect of addition PEG on the structure of PHB. The positron annihilation lifetime measurements were performed with a conventional fast-fast coincidence system. The lifetime parameter, ι3 which represents the ortho-positronium atom (o-Ps) lifetime and I 3 which reflects the (o-Ps) intensity, give indication of the free-volume size and concentration respectively. Positron annihilation lifetime measurements showed that, ι3 increases by increasing PEG ratio until the concentration (80:20 wt %) then start to decrease by increasing PEG ratio. The obtained results are in agreement with the results of X-ray diffraction.

  3. Biosynthesis of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) by bacterial community from propylene oxide saponification wastewater residual sludge.

    Science.gov (United States)

    Wang, Yiwei; Zhu, Ying; Gu, Pengfei; Li, Yumei; Fan, Xiangyu; Song, Dongxue; Ji, Yan; Li, Qiang

    2017-05-01

    The saponification wastewater from the process of propylene oxide (PO) production is contaminated with high chemical oxygen demand (COD) and chlorine contents. Although the activated sludge process could treat the PO saponification wastewater effectively, the residual sludge was difficult to be disposed properly. In this research, microbes in PO saponification wastewater residual sludge were acclimated to produce poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) from volatile fatty acids. Through Miseq Illumina highthroughput sequencing, the bacterial community discrepancy between the original and the acclimated sludge samples were analyzed. The proportions of Bacillus, Acinetobacter, Brevundimonas and Pseudomonas, the potential PHBV-producers in the residual sludge, were all obviously increased. In the batch fermentation, the production of PHBV could achieve 4.262g/L at 300min, with the content increased from 0.04% to 23.67% of mixed liquor suspended solid (MLSS) in the acclimated sludge, and the COD of the PO saponification wastewater was also decreased in the fermentation. This work would provide an effective solution for the utilization of PO saponification wastewater residual sludge. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Characterization of poly-3-hydroxybutyrate (PHB) produced from Ralstonia eutropha using an alkali-pretreated biomass feedstock.

    Science.gov (United States)

    Saratale, Ganesh D; Oh, Min-Kyu

    2015-09-01

    Alkaline pretreatment using NaOH, KOH, or NaOCl has been applied to various types of waste biomass to enhance enzymatic digestibility. Pretreatment (2% NaOH, 121 °C, 30 min) of rice paddy straw (PS) resulted in a maximum yield of 703 mg of reducing sugar per gram of PS with 84.19% hydrolysis yield after a two-step enzymatic hydrolysis process. Ralstonia eutropha ATCC 17699 was tested for its ability to synthesize poly-3-hydroxybutyrate (PHB) using PS hydrolysates as its sole carbon source. It is noteworthy that dry cell weight, polyhydroxyalkanoate (PHA) accumulation and PHB yield with the use of laboratory-grade sugars were similar to those achieved with PS-derived sugars. Under optimized conditions, we observed maximal PHA accumulation (75.45%) and PHB production (11.42 g/L) within 48 h of fermentation. After PHB recovery, the physicochemical properties of PHB were determined by various analytical techniques, showed the results were consistent with the characteristics of a standard polymer of PHB. Thus, the PS hydrolysate proved to be an excellent cheap carbon substrate for PHB production. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Poly(3-hydroxybutyrate) fuels the tricarboxylic acid cycle and de novo lipid biosynthesis during Bacillus anthracis sporulation.

    Science.gov (United States)

    Sadykov, Marat R; Ahn, Jong-Sam; Widhelm, Todd J; Eckrich, Valerie M; Endres, Jennifer L; Driks, Adam; Rutkowski, Gregory E; Wingerd, Kevin L; Bayles, Kenneth W

    2017-06-01

    Numerous bacteria accumulate poly(3-hydroxybutyrate) (PHB) as an intracellular reservoir of carbon and energy in response to imbalanced nutritional conditions. In Bacillus spp., where PHB biosynthesis precedes the formation of the dormant cell type called the spore (sporulation), the direct link between PHB accumulation and efficiency of sporulation was observed in multiple studies. Although the idea of PHB as an intracellular carbon and energy source fueling sporulation was proposed several decades ago, the mechanisms underlying PHB contribution to sporulation have not been defined. Here, we demonstrate that PHB deficiency impairs Bacillus anthracis sporulation through diminishing the energy status of the cells and by reducing carbon flux into the tricarboxylic acid (TCA) cycle and de novo lipid biosynthesis. Consequently, this metabolic imbalance decreased biosynthesis of the critical components required for spore integrity and resistance, such as dipicolinic acid (DPA) and the spore's inner membrane. Supplementation of the PHB deficient mutant with exogenous fatty acids overcame these sporulation defects, highlighting the importance of the TCA cycle and lipid biosynthesis during sporulation. Combined, the results of this work reveal the molecular mechanisms of PHB contribution to B. anthracis sporulation and provide valuable insight into the metabolic requirements for this developmental process in Bacillus species. © 2017 John Wiley & Sons Ltd.

  6. Production of (3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer from coffee waste oil using engineered Ralstonia eutropha.

    Science.gov (United States)

    Bhatia, Shashi Kant; Kim, Jung-Ho; Kim, Min-Sun; Kim, Junyoung; Hong, Ju Won; Hong, Yoon Gi; Kim, Hyun-Joong; Jeon, Jong-Min; Kim, Sang-Hyoun; Ahn, Jungoh; Lee, Hongweon; Yang, Yung-Hun

    2018-02-01

    Polyhydroxyalkonate (PHA) is a type of polymer that has the potential to replace petro-based plastics. To make PHA production more economically feasible, there is a need to find a new carbon source and engineer microbes to produce a commercially valuable polymer. Coffee waste is an inexpensive raw material that contains fatty acids. It can act as a sustainable carbon source and seems quite promising with PHA production in Ralstonia eutropha, which is a well-known microbe for PHA accumulation, and has the potential to utilize fatty acids. In this study, to make poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(HB-co-HHx)), which has superior properties in terms of biodegradability, biocompatibility, and mechanical strength, engineered strain Ralstonia eutropha Re2133 overexpressing (R)-specific enoyl coenzyme-A hydratase (phaJ) and PHA synthetase (phaC2) with deletion of acetoacetyl Co-A reductases (phaB1, phaB2, and phaB3) was used to produce PHA from coffee waste oil. At a coffee oil concentration of 1.5%, and C/N ratio of 20, the R. eutropha Re2133 fermentation process results in 69% w/w of DCW PHA accumulation and consists of HB (78 mol%) and HHx (22 mol%). This shows the feasibility of using coffee waste oil for P(HB-co-HHx) production, as it is a low-cost fatty acid enriched waste material.

  7. Efficacy of tebuconazole embedded in biodegradable poly-3-hydroxybutyrate to inhibit the development of Fusarium moniliforme in soil microecosystems.

    Science.gov (United States)

    Volova, Tatiana G; Prudnikova, Svetlana V; Zhila, Natalia O; Vinogradova, Olga N; Shumilova, Anna A; Nikolaeva, Elena D; Kiselev, Evgeniy G; Shishatskaya, Ekaterina I

    2017-05-01

    An important line of research is the development of a new generation of formulations with targeted and controlled release of the pesticide, using matrices made from biodegradable materials. In this study, slow-release formulations of the fungicide tebuconazole (TEB) have been prepared by embedding it into the matrix of poly-3-hydroxybutyrate (P3HB) in the form of films, microgranules and pellets. The average rates of P3HB degradation were determined by the geometry of the formulation, reaching, for 63 days, 0.095-0.116, 0.081-0.083 and 0.030-0.055 mg day -1 for films, microgranules and pellets respectively. The fungicidal activity of P3HB/TEB against the plant pathogen Fusarium moniliforme was compared with that of the commercial formulation Raxil Ultra. A pronounced fungicidal effect of the experimental P3HB/TEB formulations was observed in 2-4 weeks after application, and it was retained for 8 weeks, without affecting significantly the development of soil aboriginal microflora. TEB release can be regulated by the process employed to fabricate the formulation and the fungicide loading, and the TEB accumulates in the soil gradually, as the polymer is degraded. The experimental forms of TEB embedded in the slowly degraded P3HB can be used as a basis for developing slow-release fungicide formulations. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  8. Additive manufacturing of poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] scaffolds for engineered bone development.

    Science.gov (United States)

    Mota, Carlos; Wang, Shen-Yu; Puppi, Dario; Gazzarri, Matteo; Migone, Chiara; Chiellini, Federica; Chen, Guo-Qiang; Chiellini, Emo

    2017-01-01

    A wide range of poly(hydroxyalkanoate)s (PHAs), a class of biodegradable polyesters produced by various bacteria grown under unbalanced conditions, have been proposed for the fabrication of tissue-engineering scaffolds. In this study, the manufacture of poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] (or PHBHHx) scaffolds, by means of an additive manufacturing technique based on a computer-controlled wet-spinning system, was investigated. By optimizing the processing parameters, three-dimensional scaffolds with different internal architectures were fabricated, based on a layer-by-layer approach. The resulting scaffolds were characterized by scanning electron microscopy, which showed good control over the fibre alignment and a fully interconnected porous network, with porosity in the range 79-88%, fibre diameter 47-76 µm and pore size 123-789 µm. Moreover, the resulting fibres presented an internal porosity connected to the external fibre surface as a consequence of the phase-inversion process governing the solidification of the polymer solution. Scaffold compressive modulus and yield stress and strain could be varied in a certain range by changing the architectural parameters. Cell-culture experiments employing the MC3T3-E1 murine pre-osteoblast cell line showed good cell proliferation after 21 days of culture. The PHBHHx scaffolds demonstrated promising results in terms of cell differentiation towards an osteoblast phenotype. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

  9. A Comparison of Electrospun Polymers Reveals Poly(3-Hydroxybutyrate) Fiber as a Superior Scaffold for Cardiac Repair

    Science.gov (United States)

    Castellano, Delia; Blanes, María; Marco, Bruno; Cerrada, Inmaculada; Ruiz-Saurí, Amparo; Pelacho, Beatriz; Araña, Miriam; Montero, Jose A.; Cambra, Vicente; Prosper, Felipe

    2014-01-01

    The development of biomaterials for myocardial tissue engineering requires a careful assessment of their performance with regards to functionality and biocompatibility, including the immune response. Poly(3-hydroxybutyrate) (PHB), poly(e-caprolactone) (PCL), silk, poly-lactic acid (PLA), and polyamide (PA) scaffolds were generated by electrospinning, and cell compatibility in vitro, and immune response and cardiac function in vitro and in vivo were compared with a noncrosslinked collagen membrane (Col) control material. Results showed that cell adhesion and growth of mesenchymal stem cells, cardiomyocytes, and cardiac fibroblasts in vitro was dependent on the polymer substrate, with PHB and PCL polymers permitting the greatest adhesion/growth of cells. Additionally, polymer substrates triggered unique expression profiles of anti- and pro-inflammatory cytokines in human peripheral blood mononuclear cells. Implantation of PCL, silk, PLA, and PA patches on the epicardial surface of healthy rats induced a classical foreign body reaction pattern, with encapsulation of polymer fibers and induction of the nonspecific immune response, whereas Col and PHB patches were progressively degraded. When implanted on infarcted rat heart, Col, PCL, and PHB reduced negative remodeling, but only PHB induced significant angiogenesis. Importantly, Col and PHB modified the inflammatory response to an M2 macrophage phenotype in cardiac tissue, indicating a more beneficial reparative process and remodeling. Collectively, these results identify PHB as a superior substrate for cardiac repair. PMID:24564648

  10. Physical-chemical properties of nanocomposites based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and titanium dioxide nanoparticles

    Science.gov (United States)

    Braga, Natália F.; da Silva, Ana Paula; Moraes Arantes, Tatiane; Lemes, Ana Paula; Cristovan, Fernando Henrique

    2018-01-01

    Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was reinforced with titanium dioxide (TiO2) in concentrations of 1.0%, 2.5% and 5.0% (m/m) to produce nanocomposites by the solvent casting technique. TiO2 was synthesized by a hydrothermal treatment to produce nanoparticles. The nanostructure of the nanoparticles was studied by x-ray diffraction analysis (XRD) and transmission electron microscopy (TEM). The XRD confirmed TiO2 crystalline nanoparticles, with a mixture of anatase and rutile phases. Through TEM analysis, the formation of TiO2 nanorod agglomerates with an average diameter and length of 40 and 12 nm, respectively, was observed. The thermal and mechanical properties of the pure PHBV and nanocomposite films were characterized by differential scanning calorimetry (DSC) and dynamic mechanical analysis. The DSC analysis showed that the glass transition temperature decreased with the inclusion of TiO2 in the PHBV matrix in relation to pure PHBV. The results of biodegradation assays for the PHBV and nanocomposites in an aqueous medium and in soil showed morphological and structural changes for all samples, indicating a high biodegradation rate for this material. The most important conclusion is that the biodegradation of the PHBV was not affected by the addition of nanoparticles, thus enabling the use of nanocomposites in applications requiring biodegradable materials.

  11. A comparison of electrospun polymers reveals poly(3-hydroxybutyrate) fiber as a superior scaffold for cardiac repair.

    Science.gov (United States)

    Castellano, Delia; Blanes, María; Marco, Bruno; Cerrada, Inmaculada; Ruiz-Saurí, Amparo; Pelacho, Beatriz; Araña, Miriam; Montero, Jose A; Cambra, Vicente; Prosper, Felipe; Sepúlveda, Pilar

    2014-07-01

    The development of biomaterials for myocardial tissue engineering requires a careful assessment of their performance with regards to functionality and biocompatibility, including the immune response. Poly(3-hydroxybutyrate) (PHB), poly(e-caprolactone) (PCL), silk, poly-lactic acid (PLA), and polyamide (PA) scaffolds were generated by electrospinning, and cell compatibility in vitro, and immune response and cardiac function in vitro and in vivo were compared with a noncrosslinked collagen membrane (Col) control material. Results showed that cell adhesion and growth of mesenchymal stem cells, cardiomyocytes, and cardiac fibroblasts in vitro was dependent on the polymer substrate, with PHB and PCL polymers permitting the greatest adhesion/growth of cells. Additionally, polymer substrates triggered unique expression profiles of anti- and pro-inflammatory cytokines in human peripheral blood mononuclear cells. Implantation of PCL, silk, PLA, and PA patches on the epicardial surface of healthy rats induced a classical foreign body reaction pattern, with encapsulation of polymer fibers and induction of the nonspecific immune response, whereas Col and PHB patches were progressively degraded. When implanted on infarcted rat heart, Col, PCL, and PHB reduced negative remodeling, but only PHB induced significant angiogenesis. Importantly, Col and PHB modified the inflammatory response to an M2 macrophage phenotype in cardiac tissue, indicating a more beneficial reparative process and remodeling. Collectively, these results identify PHB as a superior substrate for cardiac repair.

  12. Gluconeogenesis from glycerol at rest and during exercise in normal, diabetic, and methylprednisolone-treated dogs.

    Science.gov (United States)

    Shaw, W A; Issekutz, T B; Issekutz, B

    1976-03-01

    Glucose turnover, glycerol turnover, and the rate of incorporation of glycerol carbon into glucose were measured with the tracer technique (primed constant rate infusion) using 2-3H-glucose and 14C-glycerol, at rest and during exercise (treadmill run) in normal (N), alloxan-diabetic (D), and methylprednisolone treated diabetic (MPD) dogs. At rest only 2%-3% of the hepatic glucose output arose from glycerol. Exercise increased gluconeogenesis about ninefold in N dogs and about fourfold in D and MPD animals, yet less than 9% of the elevated glucose turnover was derived from glycerol. There was a direct linear correlation between the rates of glycerol turnover and gluconeogenesis from glycerol at rest and during exercise in all three groups. The slope constants were however significantly different: 0.45, 0.51, and 0.67 for N, D, and MPD dogs, respectively. In vivo the major factor controlling the rate of gluconeogenesis from glycerol seems to be the glycerol supply on which the specific effects of insulin deficiency and glucocorticoid treatment are superimposed. They appear to be of minor importance. A comparison of the glucose turnover measured by 2-3H-glucose with that measured by 6-3H-glucose showed that the activity of the glucose in equilibrium glucose-6-P cycle was threefold higher in D dogs and elevated by 15-fold in MPD animals.

  13. Preparation and characterization of ibuprofen-loaded microspheres consisting of poly(3-hydroxybutyrate) and methoxy poly (ethylene glycol)-b-poly (D,L-lactide) blends or poly(3-hydroxybutyrate) and gelatin composites for controlled drug release

    International Nuclear Information System (INIS)

    Bidone, Juliana; Melo, Ana Paula P.; Bazzo, Giovana C.; Carmignan, Francoise; Soldi, Marli S.; Pires, Alfredo T.N.; Lemos-Senna, Elenara

    2009-01-01

    Poly-(3-hydroxybutyrate) (P(3HB)) is a biodegradable and biocompatible polymer that has been used to obtain polymer-based drug carriers. However, due to the high crystallinity degree of this polymer, drug release from P(3HB) microspheres frequently occurs at excessive rates. In this study, two strategies for prolonging ibuprofen release from P(3HB)-based microspheres were tested: blending with poly(D,L-lactide)-b-polyethylene glycol (mPEG-PLA); and obtaining composite particles with gelatin (GEL). SEM micrographs showed particles that were spherical and had a rough surface. A slight decrease of the crystallinity degree of P(3HB) was observed only in the DSC thermogram obtained from unloaded-microspheres prepared from 1:1 P(3HB):mPEG-PLA blend. For IBF-loaded microspheres, a reduction of around 10 deg. C in the melting temperature of P(3HB) was observed, indicating that the crystalline structure of the polymer was affected in the presence of the drug. DSC studies also yielded evidence of the presence of a molecular dispersion coexisting with a crystalline dispersion in the drug in the matrix. Similar results were obtained from X-ray diffractograms. In spite of 1:1 mPEG-PLA:P(3HB) blends having contributed to the reduction of the burst effect, a more controlled drug release was provided by the use of the 3:1 P(3HB):mPEGPLA blend. This result indicated that particle hydration played an important role in the drug release. On the other hand, the preparation of P(3HB):GEL composite microspheres did not allow control of the IBF release

  14. Production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) under photoautotrophy and heterotrophy by non-heterocystous N2-fixing cyanobacterium.

    Science.gov (United States)

    Taepucharoen, Keerati; Tarawat, Somchai; Puangcharoen, Monthira; Incharoensakdi, Aran; Monshupanee, Tanakarn

    2017-09-01

    The photoautotrophically grown cyanobacterium Oscillatoria okeni TISTR 8549 was found to produce bioplastic poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). This PHBV production occurred under nitrogen deprivation (-N) that yielded PHBV accumulation of 14±4% (w/w DW) in which 3-hydroxyvalerate accounted for 5.5mol%. The heterotrophically grown (-N condition with acetate supplementation) cells under light showed no increase of PHBV storage, but under dark condition these cells increased PHBV accumulation to 42±8% (w/w DW) with 6.5mol% of 3-hydroxyvalerate. Compared to poly-3-hydroxybutyrate (PHB), the PHBV from O. okeni had a lower melting temperature by 5-7°C, a higher % elongation at break by 4-7times and a greater Young's elastic modulus by 2.3-2.5times. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Effects of propionate and methylmalonate on conversions of acetate, butyrate, and D(-)-3-hydroxybutyrate to fatty acids and carbon dioxide by mammary tissue slices of goats

    International Nuclear Information System (INIS)

    Emmanuel, B.; Kennelly, J.J.

    1985-01-01

    Incorporations of [1-carbon-14] acetate, [1-carbon-14] propionate, n-[1-carbon-14] butyrate, and D(-)-3-hydroxy[3-carbon-14] butyrate into individual milk fatty acids and their conversion to carbon dioxide were studied in vitro with caprine mammary tissue slices in the presence and absence of propionate and methylmalonate. Neither propionate nor methylmalonate affected incorporation of these substances into fatty acids. In a decreasing order butyrate, acetate, propionate, and D(-)-3-hydroxybutyrate were converted to carbon dioxide. Acetate had the highest incorporation rate into fatty acids followed by D(-)-3-hydroxybutyrate, butyrate, and propionate. Labeled propionate was incorporated mainly into odd-numbered fatty acids. Results do not support the theory that either propionate or its metabolite, methylmalonate, inhibit de novo synthesis of fatty acids in the mammary gland in relation to the etiology of low milk fat syndrome

  16. Promoting the Recovery of Injured Liver with Poly (3-Hydroxybutyrate-Co-3-Hydroxyvalerate-Co-3-Hydroxyhexanoate) Scaffolds Loaded with Umbilical Cord-Derived Mesenchymal Stem Cells

    OpenAIRE

    Li, Pengshan; Zhang, Jin; Liu, Jing; Ma, Huan; Liu, Jie; Lie, Puchang; Wang, Yuechun; Liu, Gexiu; Zeng, Huilan; Li, Zhizhong; Wei, Xing

    2014-01-01

    Cell-based therapies are major focus of current research for treatment of liver diseases. In this study, mesenchymal stem cells were isolated from human umbilical cord Wharton's jelly (WJ-MSCs). Results confirmed that WJ-MSCs isolated in this study could express the typical MSC-specific markers and be induced to differentiate into adipocytes, osteoblasts, and chondrocytes. They could also be induced to differentiate into hepatocyte-like cells. Poly (3-hydroxybutyrate-co-3-hydroxyvalerate-co-3...

  17. Chemical modification of biodegradable polymer poly(3-hydroxybutyrate) by poly(ethylene oxide); Modificacao quimica do polimero biodegradavel poli(3-hidroxibutirato) com poly(oxido de etileno)

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Lilian L.; Rocha, Gisele A.; Hui, Wang S., E-mail: wangshui@usp.b [Universidade de Sao Paulo (EP/USP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Metalurgica e de Materiais

    2009-07-01

    Catalyzed transesterification in the melt was used to produce triblock copolymers from poly(3-hydroxybutyrate) (PHB) and poly(ethyleneoxide) (PEG), in a simplified process. PHB of high molecular weight was depolymerized by pyrolysis and transesterification with dihydroxy terminated PEG occurred through consecutive and partly simultaneous reactions. The effectiveness of the process was verified by the characterization of the formed copolymers by Hydrogen and Carbon-13 Nuclear Magnetic Resonance Spectroscopies (NMR) and solubility analysis in a series of solvents. (author)

  18. Poly(3-hydroxybutyrate-co-R-3-hydroxyhexanoate) nanoparticles with polyethylenimine coat as simple, safe, and versatile vehicles for cell targeting: population characteristics, cell uptake, and intracellular trafficking.

    Science.gov (United States)

    Wu, Lin-Ping; Wang, Danyang; Parhamifar, Ladan; Hall, Arnaldur; Chen, Guo-Qiang; Moghimi, Seyed M

    2014-06-01

    A simple and highly safe poly(3-hydroxybutyrate-co-R-3-hydroxyhexanoate) nanoparticulate delivery system that targets different cell types is developed. A sub-cytotoxic level of polyethylenimine coat mediates universal cell targeting. Internalized nanoparticles traffic along endolysosomal compartments, endoplasmic reticulum and the Golgi complex. Nanoparticles have no detrimental effects on cell morphology and respiration. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Improvement of (R)-3-hydroxybutyric acid secretion during Halomonas sp. KM-1 cultivation with saccharified Japanese cedar by the addition of urea.

    Science.gov (United States)

    Kawata, Y; Nojiri, M; Matsushita, I; Tsubota, J

    2015-10-01

    Japanese cedar (Cryptomeria japonica) is a major species in artificial Japanese forests. The Halomonas sp. KM-1 was recently isolated and found to grow effectively on saccharified Japanese cedar wood, resulting in the intracellular storage of poly-(R)-3-hydroxybutyric acid (PHB) under aerobic conditions. Under microaerobic conditions, the extracellular secretion of (R)-3-hydroxybutyric acid ((R)-3-HB) led to the degradation of intracellular PHB. In this study, the production of PHB and the secretion of (R)-3-HB using saccharified Japanese cedar were much improved in cultures that were grown in the presence of urea. The level of intracellular PHB production after 36 h under aerobic cultivation was 23·6 g l(-1) ; after shifting to microaerobic conditions for 24 h, the (R)-3-HB concentration in the medium reached 21·1 g l(-1) . Thus, KM-1 efficiently utilizes saccharified Japanese cedar to produce PHB and secretes (R)-3-HB, making it a practical candidate for use in the industrial production of (R)-3-HB. Japanese cedar is a major species grown in artificial Japanese forests, and its thinning is crucial for the health of artificial forests and the Japanese economy. Halomonas sp. KM-1 grew effectively on saccharified Japanese cedar wood, resulting in intracellular storage of poly-(R)-3-hydroxybutyric acid (PHB) under aerobic conditions. Under microaerobic conditions, extracellular secretion of (R)-3-hydroxybutyric acid ((R)-3-HB) caused intracellular PHB degradation. (R)-3-HB is a chiral compound that is useful in the chemical, health food and pharmaceutical industries. The production of PHB and secretion of (R)-3-HB using saccharified wood was dramatically improved, which may positively affect its future industrial production. © 2015 The Society for Applied Microbiology.

  20. Production of Poly(3-Hydroxybutyrate-co-3-Hydroxyhexanoate) from Plant Oil by Engineered Ralstonia eutropha Strains▿†

    Science.gov (United States)

    Budde, Charles F.; Riedel, Sebastian L.; Willis, Laura B.; Rha, ChoKyun; Sinskey, Anthony J.

    2011-01-01

    The polyhydroxyalkanoate (PHA) copolymer poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(HB-co-HHx)] has been shown to have potential to serve as a commercial bioplastic. Synthesis of P(HB-co-HHx) from plant oil has been demonstrated with recombinant Ralstonia eutropha strains expressing heterologous PHA synthases capable of incorporating HB and HHx into the polymer. With these strains, however, short-chain-length fatty acids had to be included in the medium to generate PHA with high HHx content. Our group has engineered two R. eutropha strains that accumulate high levels of P(HB-co-HHx) with significant HHx content directly from palm oil, one of the world's most abundant plant oils. The strains express a newly characterized PHA synthase gene from the bacterium Rhodococcus aetherivorans I24. Expression of an enoyl coenzyme A (enoyl-CoA) hydratase gene (phaJ) from Pseudomonas aeruginosa was shown to increase PHA accumulation. Furthermore, varying the activity of acetoacetyl-CoA reductase (encoded by phaB) altered the level of HHx in the polymer. The strains with the highest PHA titers utilized plasmids for recombinant gene expression, so an R. eutropha plasmid stability system was developed. In this system, the essential pyrroline-5-carboxylate reductase gene proC was deleted from strain genomes and expressed from a plasmid, making the plasmid necessary for growth in minimal media. This study resulted in two engineered strains for production of P(HB-co-HHx) from palm oil. In palm oil fermentations, one strain accumulated 71% of its cell dry weight as PHA with 17 mol% HHx, while the other strain accumulated 66% of its cell dry weight as PHA with 30 mol% HHx. PMID:21398488

  1. In vitro biocompatibility of 45S5 Bioglass-derived glass-ceramic scaffolds coated with poly(3-hydroxybutyrate).

    Science.gov (United States)

    Bretcanu, Oana; Misra, Superb; Roy, Ipsita; Renghini, Chiara; Fiori, Fabrizio; Boccaccini, Aldo R; Salih, Vehid

    2009-02-01

    The aim of this work was to study the in vitro biocompatibility of glass-ceramic scaffolds based on 45S5 Bioglass, using a human osteosarcoma cell line (HOS-TE85). The highly porous scaffolds were produced by the foam replication technique. Two different types of scaffolds with different porosities were analysed. They were coated with a biodegradable polymer, poly(3-hydroxybutyrate) (P(3HB)). The scaffold bioactivity was evaluated by soaking in a simulated body fluid (SBF) for different durations. Compression strength tests were performed before and after immersion in SBF. These experiments showed that the scaffolds are highly bioactive, as after a few days of immersion in SBF a hydroxyapatite-like layer was formed on the scaffold's surface. It was also observed that P(3HB)-coated samples exhibited higher values of compression strength than uncoated samples. Biocompatibility assessment was carried out by qualitative evaluation of cell morphology after different culture periods, using scanning electron microscopy, while cell proliferation was determined by using the AlamarBlue assay. Alkaline phosphatase (ALP) and osteocalcin (OC) assays were used as quantitative in vitro indicators of osteoblast function. Two different types of medium were used for ALP and OC tests: normal supplemented medium and osteogenic medium. HOS cells were seeded and cultured onto the scaffolds for up to 2 weeks. The AlamarBlue assay showed that cells were able to proliferate and grow on the scaffold surface. After 7 days in culture, the P(3HB)-coated samples had a higher number of cells on their surfaces than the uncoated samples. Regarding ALP- and OC-specific activity, no significant differences were found between samples with different pore sizes. All scaffolds containing osteogenic medium seemed to have a slightly higher level of ALP and OC concentration. These experiments confirmed that Bioglass/P(3HB) scaffolds have potential as osteoconductive tissue engineering substrates for

  2. A two-step enzymatic resolution process for large-scale production of (S)- and (R)-ethyl-3-hydroxybutyrate.

    Science.gov (United States)

    Fishman, A; Eroshov, M; Dee-Noor, S S; van Mil, J; Cogan, U; Effenberger, R

    2001-08-05

    An efficient two-step enzymatic process for production of (R)- and (S)-ethyl-3-hydroxybutyrate (HEB), two important chiral intermediates for the pharmaceutical market, was developed and scaled-up to a multikilogram scale. Both enantiomers were obtained at 99% chemical purity and over 96% enantiomeric excess, with a total process yield of 73%. The first reaction involved a solvent-free acetylation of racemic HEB with vinylacetate for the production of (S)-HEB. In the second reaction, (R)-enriched ethyl-3-acetoxybutyrate (AEB) was subjected to alcoholysis with ethanol to derive optically pure (R)-HEB. Immobilized Candida antarctica lipase B (CALB) was employed in both stages, with high productivity and selectivity. The type of butyric acid ester influenced the enantioselectivity of the enzyme. Thus, extending the ester alkyl chain from ethyl to octyl resulted in a decrease in enantiomeric excess, whereas using bulky groups such as benzyl or t-butyl, improved the enantioselectivity of the enzyme. A stirred reactor was found unsuitable for large-scale production due to attrition of the enzyme particles and, therefore, a batchwise loop reactor system was used for bench-scale production. The immobilized enzyme was confined to a column and the reactants were circulated through the enzyme bed until the targeted conversion was reached. The desired products were separated from the reaction mixture in each of the two stages by fractional distillation. The main features of the process are the exclusion of solvent (thus ensuring high process throughput), and the use of the same enzyme for both the acetylation and the alcoholysis steps. Kilogram quantities of (S)-HEB and (R)-HEB were effectively prepared using this unit, which can be easily scaled-up to produce industrial quantities. Copyright 2001 John Wiley & Sons, Inc.

  3. Poly(3-hydroxybutyrate)/metribuzin formulations: characterization, controlled release properties, herbicidal activity, and effect on soil microorganisms.

    Science.gov (United States)

    Volova, Tatiana; Zhila, Natalia; Kiselev, Evgeniy; Prudnikova, Svetlana; Vinogradova, Olga; Nikolaeva, Elena; Shumilova, Anna; Shershneva, Anna; Shishatskaya, Ekaterina

    2016-12-01

    Slow-release formulations of the herbicide metribuzin (MET) embedded in the polymer matrix of degradable poly-3-hydroxybutyrate [P(3HB)] in the form of microparticles, films, microgranules, and pellets were developed and tested. The kinetics of polymer degradation, MET release, and accumulation in soil were studied in laboratory soil microecosystems with higher plants. The study shows that MET release can be controlled by using different techniques of constructing formulations and by varying MET loading. MET accumulation in soil occurs gradually, as the polymer is degraded. The average P(3HB) degradation rates were determined by the geometry of the formulation, reaching 0.17, 0.12, 0.04, and 0.05 mg/day after 60 days for microparticles, films, microgranules, and pellets, respectively. The herbicidal activities of P(3HB)/MET formulations and commercial formulation Sencor Ultra were tested on the Agrostis stolonifera and Setaria macrocheata plants. The parameters used to evaluate the herbicidal activity were plant density and the weight of fresh green biomass measured at days 10, 20, and 30 after sowing. All P(3HB)/MET formulations had pronounced herbicidal activity, which varied depending on MET loading and the stage of the experiment. In the early phases of the experiment, the herbicidal effect of P(3HB)/MET formulations with the lowest MET loading (10 %) was comparable with that of the commercial formulation. The herbicidal effect of P(3HB)/MET formulations with higher MET loadings (25 and 50 %) at later stages of the experiment were stronger than the effect of Sencor Ultra.

  4. Identification and characterization of a novel class of extracellular poly(3-hydroxybutyrate) depolymerase from Bacillus sp. strain NRRL B-14911.

    Science.gov (United States)

    Ma, Wan-Ting; Lin, Ju-Hui; Chen, Hui-Ju; Chen, Syuan-Yi; Shaw, Gwo-Chyuan

    2011-11-01

    The catalytic, linker, and denatured poly(3-hydroxybutyrate) (dPHB)-binding domains of bacterial extracellular PHB depolymerases (PhaZs) are classified into several different types. We now report a novel class of extracellular PHB depolymerase from Bacillus sp. strain NRRL B-14911. Its catalytic domain belongs to type 1, whereas its putative linker region neither possesses the sequence features of the three known types of linker domains nor exhibits significant amino acid sequence similarity to them. Instead, this putative linker region can be divided into two distinct linker domains of novel types: LD1 and LD2. LD1 shows significant amino acid sequence similarity to certain regions of a large group of PHB depolymerase-unrelated proteins. LD2 and its homologs are present in a small group of PhaZs. The remaining C-terminal portion of this PhaZ can be further divided into two distinct domains: SBD1 and SBD2. Each domain showed strong binding to dPHB, and there is no significant sequence similarity between them. Each domain neither possesses the sequence features of the two known types of dPHB-binding domains nor shows significant amino acid sequence similarity to them. These unique features indicate the presence of two novel and distinct types of dPHB-binding domains. Homologs of these novel domains also are present in the extracellular PhaZ of Bacillus megaterium and the putative extracellular PhaZs of Bacillus pseudofirmus and Bacillus sp. strain SG-1. The Bacillus sp. NRRL B-14911 PhaZ appears to be a representative of a novel class of extracellular PHB depolymerases.

  5. Novel poly(3-hydroxybutyrate) nanocomposites containing WS{sub 2} inorganic nanotubes with improved thermal, mechanical and tribological properties

    Energy Technology Data Exchange (ETDEWEB)

    Naffakh, Mohammed, E-mail: mohammed.naffakh@upm.es [Universidad Politécnica de Madrid, Departamento de Ingeniería y Ciencia de los Materiales, Escuela Técnica Superior de Ingenieros Industriales, José Gutiérrez Abascal 2, 28006 Madrid (Spain); Marco, Carlos; Ellis, Gary [CSIC, Instituto de Ciencia y Tecnología de Polímeros (ICTP), Juan de la Cierva 3, 28006 Madrid (Spain); Cohen, Sidney R. [Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100 (Israel); Laikhtman, Alexander; Rapoport, Lev; Zak, Alla [Department of Sciences, Holon Institute of Technology, 52 Golomb St., Holon 58102 (Israel)

    2014-09-15

    Poly(3-hydroxybutyrate) (PHB) nanocomposites containing environmentally-friendly tungsten disulphide inorganic nanotubes (INT–WS{sub 2}) have been successfully prepared by a simple solution blending method. The dynamic and isothermal crystallization studies by differential scanning calorimetry (DSC) demonstrated that the INT–WS{sub 2} exhibits much more prominent nucleation activity on the crystallization of PHB than specific nucleating agents or other nanoscale fillers. Both crystallization rate and crystallinity significantly increase in the nanocomposites compared to neat PHB. These changes occur without modifying the crystalline structure of PHB in the nanocomposites, as shown by wide-angle X-ray diffraction (WAXS) and infrared/Raman spectroscopy. Other parameters such as the Avrami exponent, the equilibrium melting temperature, global rate constant and the fold surface free energy of PHB chains in the nanocomposites were obtained from the calorimetric data in order to determine the influence of the INT–WS{sub 2} filler. The addition of INT–WS{sub 2} remarkably influences the energetics and kinetics of nucleation and growth of PHB, reducing the fold surface free energy by up to 20%. Furthermore, these nanocomposites also show an improvement in both tribological and mechanical (hardness and modulus) properties with respect to pure PHB evidenced by friction and nanoindentation tests, which is of important potential interest for industrial and medical applications. - Highlights: • Environmentally-friendly INT–WS{sub 2} is used to produce advanced PHB NCPs. • Novel PHB NCPs are obtained without using modifiers or surfactants. • Novel INT–WS{sub 2} improve the thermal and mechanical properties of PHB. • INT–WS{sub 2} is effective in reducing the friction coefficient of PHB. • The benefits of using INTs compared to other nanoscale fillers are highlighted.

  6. Factors Affecting Poly(3-hydroxybutyrate Production from Oil Palm Frond Juice by Cupriavidus necator (CCUG52238T

    Directory of Open Access Journals (Sweden)

    Mior Ahmad Khushairi Mohd Zahari

    2012-01-01

    Full Text Available Factors influencing poly(3-hydroxybutyrate P(3HB production by  Cupriavidus necator  CCUG52238T utilizing oil palm frond (OPF juice were clarified in this study. Effects of initial medium pH, agitation speed, and ammonium sulfate (NH42SO4 concentration on the production of P(3HB were investigated in shake flasks experiments using OPF juice as the sole carbon source. The highest P(3HB content was recorded at pH 7.0, agitation speed of 220 rpm, and (NH42SO4 concentration at 0.5 g/L. By culturing the wild-type strain of C. necator under the aforementioned conditions, the cell dry weight (CDW and P(3HB content obtained were 9.31 ± 0.13 g/L and 45 ± 1.5 wt.%, respectively. This accounted for 40% increment of P(3HB content compared to the nonoptimized condition. In the meanwhile, the effect of dissolved oxygen tension (DOT on P(3HB production was investigated in a 2-L bioreactor. Highest CDW (11.37 g/L and P(3HB content (44 wt.% were achieved when DOT level was set at 30%. P(3HB produced from OPF juice had a tensile strength of 40 MPa and elongation at break of 8% demonstrated that P(3HB produced from renewable and cheap carbon source is comparable to those produced from commercial substrate.

  7. Identification and characterization of the intracellular poly-3-hydroxybutyrate depolymerase enzyme PhaZ of Sinorhizobium meliloti

    Directory of Open Access Journals (Sweden)

    Zachertowska Alicja

    2010-03-01

    Full Text Available Abstract Background S. meliloti forms indeterminate nodules on the roots of its host plant alfalfa (Medicago sativa. Bacteroids of indeterminate nodules are terminally differentiated and, unlike their non-terminally differentiated counterparts in determinate nodules, do not accumulate large quantities of Poly-3-hydroxybutyrate (PHB during symbiosis. PhaZ is in intracellular PHB depolymerase; it represents the first enzyme in the degradative arm of the PHB cycle in S. meliloti and is the only enzyme in this half of the PHB cycle that remains uncharacterized. Results The S. meliloti phaZ gene was identified by in silico analysis, the ORF was cloned, and a S. meliloti phaZ mutant was constructed. This mutant exhibited increased PHB accumulation during free-living growth, even when grown under non-PHB-inducing conditions. The phaZ mutant demonstrated no reduction in symbiotic capacity; interestingly, analysis of the bacteroids showed that this mutant also accumulated PHB during symbiosis. This mutant also exhibited a decreased capacity to tolerate long-term carbon starvation, comparable to that of other PHB cycle mutants. In contrast to other PHB cycle mutants, the S. meliloti phaZ mutant did not exhibit any decrease in rhizosphere competitiveness; however, this mutant did exhibit a significant increase in succinoglycan biosynthesis. Conclusions S. meliloti bacteroids retain the capacity to synthesize PHB during symbiosis; interestingly, accumulation does not occur at the expense of symbiotic performance. phaZ mutants are not compromised in their capacity to compete for nodulation in the rhizosphere, perhaps due to increased succinoglycan production resulting from upregulation of the succinoglycan biosynthetic pathway. The reduced survival capacity of free-living cells unable to access their accumulated stores of PHB suggests that PHB is a crucial metabolite under adverse conditions.

  8. Additive Manufacturing of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)/poly(ε-caprolactone) Blend Scaffolds for Tissue Engineering.

    Science.gov (United States)

    Puppi, Dario; Morelli, Andrea; Chiellini, Federica

    2017-05-24

    Additive manufacturing of scaffolds made of a polyhydroxyalkanoate blended with another biocompatible polymer represents a cost-effective strategy for combining the advantages of the two blend components in order to develop tailored tissue engineering approaches. The aim of this study was the development of novel poly(3-hydroxybutyrate- co -3-hydroxyhexanoate)/ poly(ε-caprolactone) (PHBHHx/PCL) blend scaffolds for tissue engineering by means of computer-aided wet-spinning, a hybrid additive manufacturing technique suitable for processing polyhydroxyalkanoates dissolved in organic solvents. The experimental conditions for processing tetrahydrofuran solutions containing the two polymers at different concentrations (PHBHHx/PCL weight ratio of 3:1, 2:1 or 1:1) were optimized in order to manufacture scaffolds with predefined geometry and internal porous architecture. PHBHHx/PCL scaffolds with a 3D interconnected network of macropores and a local microporosity of the polymeric matrix, as a consequence of the phase inversion process governing material solidification, were successfully fabricated. As shown by scanning electron microscopy, thermogravimetric, differential scanning calorimetric and uniaxial compressive analyses, blend composition significantly influenced the scaffold morphological, thermal and mechanical properties. In vitro biological characterization showed that the developed scaffolds were able to sustain the adhesion and proliferation of MC3T3-E1 murine preosteoblast cells. The additive manufacturing approach developed in this study, based on a polymeric solution processing method avoiding possible material degradation related to thermal treatments, could represent a powerful tool for the development of customized PHBHHx-based blend scaffolds for tissue engineering.

  9. Assessment of poly(ε-caprolactone)/poly(3-hydroxybutyrate-co-3-hydroxyvalerate) blends processed by solvent casting and electrospinning

    International Nuclear Information System (INIS)

    Del Gaudio, Costantino; Ercolani, Enrico; Nanni, Francesca; Bianco, Alessandra

    2011-01-01

    Research highlights: → PHBV, PCL and blends were processed in form of solvent cast films and e-spun mats. → A clear phase separation was observed for cast films when blended in equal amount. → E-spun blends were comprised of uniform and defect-free randomly arranged fibers. → DSC and XRD analyses demonstrated the immiscibility of PHBV and PCL. → Rearrangement of e-spun fibers and neckings, after axial test, were observed. - Abstract: Poly(ε-caprolactone) (PCL) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) were blended in different ratio, e.g. 30/70, 50/50 and 70/30 (w/w), by means of solvent casting or electrospinning. Microstructure, thermal and mechanical properties of cast films and non-woven mats were investigated by means of scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), differential scanning calorimetry (DSC), and uniaxial tensile test. The microstructure of PHBV/PCL solvent cast films (thickness 65-100 μm) was strictly dependent on the composition of the blend, a clean phase separation was observed for the 50/50 (w/w) sample. All electrospun PHBV/PCL blends (thickness 350-800 μm) were characterised by uniform and homogenous fibers, the average size was about 3 μm. Both techniques led to polymeric blends comprised of separate crystalline domains associated to an amorphous interdisperse phase. It has also been demonstrated that electrospun PHBV/PCL blends showed a lower segregation degree among the crystalline domains. Solvent cast blends were characterised by superior mechanical properties in terms of tensile modulus and tensile strength compared to electrospun ones. Fractured electrospun blends showed an overall fiber rearrangement in the direction of the applied load, eventually highlighting multiple necking regions along the fibers.

  10. Biocomposite scaffolds based on electrospun poly(3-hydroxybutyrate) nanofibers and electrosprayed hydroxyapatite nanoparticles for bone tissue engineering applications

    International Nuclear Information System (INIS)

    Ramier, Julien; Bouderlique, Thibault; Stoilova, Olya; Manolova, Nevena; Rashkov, Iliya; Langlois, Valérie; Renard, Estelle; Albanese, Patricia; Grande, Daniel

    2014-01-01

    The electrospinning technique combined with the electrospraying process provides a straightforward and versatile approach for the fabrication of novel nanofibrous biocomposite scaffolds with structural, mechanical, and biological properties potentially suitable for bone tissue regeneration. In this comparative investigation, three types of poly(3-hydroxybutyrate) (PHB)-based scaffolds were engineered: (i) PHB mats by electrospinning of a PHB solution, (ii) mats of PHB/hydroxyapatite nanoparticle (nHA) blends by electrospinning of a mixed solution containing PHB and nHAs, and (iii) mats constituted of PHB nanofibers and nHAs by simultaneous electrospinning of a PHB solution and electrospraying of a nHA dispersion. Scaffolds based on PHB/nHA blends displayed improved mechanical properties compared to those of neat PHB mats, due to the incorporation of nHAs within the fibers. The electrospinning/electrospraying approach afforded biocomposite scaffolds with lower mechanical properties, due to their higher porosity, but they displayed slightly better biological properties. In the latter case, the bioceramic, i.e. nHAs, largely covered the fiber surface, thus allowing for a direct exposure to cells. The 21 day-monitoring through the use of MTS assays and SEM analyses demonstrated that human mesenchymal stromal cells (hMSCs) remained viable on PHB/nHA biocomposite scaffolds and proliferated continuously until reaching confluence. - Highlights: • Three different types of PHB-based scaffolds are engineered and thoroughly investigated. • The combination of electrospinning and electrospraying affords original nanofibrous biocomposite scaffolds. • PHB-based scaffolds show a strong capability of supporting viable cell development for 21 days

  11. Metabolic engineering for high glycerol production by the anaerobic cultures of Saccharomyces cerevisiae.

    Science.gov (United States)

    Semkiv, Marta V; Dmytruk, Kostyantyn V; Abbas, Charles A; Sibirny, Andriy A

    2017-06-01

    Glycerol is used by the cosmetic, paint, automotive, food, and pharmaceutical industries and for production of explosives. Currently, glycerol is available in commercial quantities as a by-product from biodiesel production, but the purity and the cost of its purification are prohibitive. The industrial production of glycerol by glucose aerobic fermentation using osmotolerant strains of the yeasts Candida sp. and Saccharomyces cerevisiae has been described. A major drawback of the aerobic process is the high cost of production. For this reason, the development of yeast strains that effectively convert glucose to glycerol anaerobically is of great importance. Due to its ability to grow under anaerobic conditions, the yeast S. cerevisiae is an ideal system for the development of this new biotechnological platform. To increase glycerol production and accumulation from glucose, we lowered the expression of TPI1 gene coding for triose phosphate isomerase; overexpressed the fused gene consisting the GPD1 and GPP2 parts coding for glycerol-3-phosphate dehydrogenase and glycerol-3-phosphate phosphatase, respectively; overexpressed the engineered FPS1 gene that codes for aquaglyceroporin; and overexpressed the truncated gene ILV2 that codes for acetolactate synthase. The best constructed strain produced more than 20 g of glycerol/L from glucose under micro-aerobic conditions and 16 g of glycerol/L under anaerobic conditions. The increase in glycerol production led to a drop in ethanol and biomass accumulation.

  12. Chemical equilibrium of glycerol carbonate synthesis from glycerol

    International Nuclear Information System (INIS)

    Li Jiabo; Wang Tao

    2011-01-01

    Research highlights: → Transesterification of glycerol with cyclic carbonates or alkyl carbonates is thermodynamically favourable for the preparation of glycerol carbonate from glycerol. → The reaction of glycerol and carbon dioxide is thermodynamically limited. → High temperature and low pressure is favourable to the reaction of glycerol and urea. → Increasing temperature can increase the chemical equilibrium constant for the reaction of glycerol and dimethyl carbonate. → For the reaction of glycerol and ethylene carbonate, increasing temperature can decrease the chemical equilibrium constant. - Abstract: In this paper, the chemical equilibrium for the glycerol carbonate preparation from glycerol was investigated. The chemical equilibrium constants were calculated for the reactions to produce glycerol carbonate from glycerol. The theoretical calculation was compared with the experimental results for the transesterification of glycerol with dimethyl carbonate. Transesterification of glycerol with cyclic carbonates or alkyl carbonates is thermodynamically favourable for producing glycerol carbonate from glycerol according to the equilibrium constant. Increasing temperature can increase the chemical equilibrium constant for the reaction of glycerol with dimethyl carbonate. For the reaction of glycerol with ethylene carbonate, increasing temperature can decrease the chemical equilibrium constant. The reaction of glycerol with carbon dioxide is thermodynamically limited. High temperature and low pressure are favourable to the reaction of glycerol and urea.

  13. Cupriavidus malaysiensis sp. nov., a novel poly(3-hydroxybutyrate-co-4-hydroxybutyrate) accumulating bacterium isolated from the Malaysian environment.

    Science.gov (United States)

    Ramachandran, Hema; Shafie, Nur Asilla Hani; Sudesh, Kumar; Azizan, Mohamad Noor; Majid, Mohamad Isa Abdul; Amirul, Al-Ashraf Abdullah

    2018-03-01

    Bacterial classification on the basis of a polyphasic approach was conducted on three poly(3 hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] accumulating bacterial strains that were isolated from samples collected from Malaysian environments; Kulim Lake, Sg. Pinang river and Sg. Manik paddy field. The Gram-negative, rod-shaped, motile, non-sporulating and non-fermenting bacteria were shown to belong to the genus Cupriavidus of the Betaproteobacteria on the basis of their 16S rRNA gene sequence analyses. The sequence similarity value with their near phylogenetic neighbour, Cupriavidus pauculus LMG3413 T , was 98.5%. However, the DNA-DNA hybridization values (8-58%) and ribotyping analysis both enabled these strains to be differentiated from related Cupriavidus species with validly published names. The RiboPrint patterns of the three strains also revealed that the strains were genetically related even though they displayed a clonal diversity. The major cellular fatty acids detected in these strains included C15:0 ISO 2OH/C16:1 ω7c, hexadecanoic (16:0) and cis-11-octadecenoic (C18:1 ω7c). Their G+C contents ranged from 68.0  to 68.6 mol%, and their major isoprenoid quinone was Ubiquinone Q-8. Of these three strains, only strain USMAHM13 (= DSM 25816 = KCTC 32390) was discovered to exhibit yellow pigmentation that is characteristic of the carotenoid family. Their assembled genomes also showed that the three strains were not identical in terms of their genome sizes that were 7.82, 7.95 and 8.70 Mb for strains USMAHM13, USMAA1020 and USMAA2-4, respectively, which are slightly larger than that of Cupriavidus necator H16 (7.42 Mb). The average nucleotide identity (ANI) results indicated that the strains were genetically related and the genome pairs belong to the same species. On the basis of the results obtained in this study, the three strains are considered to represent a novel species for which the name Cupriavidus malaysiensis sp. nov. is proposed. The

  14. Crude glycerol-based production of amino acids and putrescine by Corynebacterium glutamicum.

    Science.gov (United States)

    Meiswinkel, Tobias M; Rittmann, Doris; Lindner, Steffen N; Wendisch, Volker F

    2013-10-01

    Corynebacterium glutamicum possesses genes for glycerol kinase and glycerol-3-phosphate dehydrogenase that were shown to support slow growth with glycerol only when overexpressed from a plasmid. Pure glycerol and crude glycerol from biodiesel factories were tested for growth of recombinant strains expressing glpF, glpK and glpD from Escherichia coli. Some, but not all crude glycerol lots served as good carbon sources. Although the inhibitory compound(s) present in these crude glycerol lots remained unknown, the addition of substoichiometric glucose concentrations (below 10% by weight) enabled the utilization of some of the inhibitory crude glycerol lots. Besides growth, production of the amino acids L-glutamate, L-lysine, L-ornithine and L-arginine as well as of the diamine putrescine based on crude glycerol qualities from biodiesel factories was demonstrated. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Synthesis of Diblock copolymer poly-3-hydroxybutyrate -block-poly-3-hydroxyhexanoate [PHB-b-PHHx] by a β-oxidation weakened Pseudomonas putida KT2442

    DEFF Research Database (Denmark)

    Tripathi, Lakshmi; Wu, Lin-Ping; Chen, Jinchun

    2012-01-01

    BACKGROUND: Block polyhydroxyalkanoates (PHA) were reported to be resistant against polymer aging that negatively affects polymer properties. Recently, more and more attempts have been directed to make PHA block copolymers. Diblock copolymers PHB-b-PHHx consisting of poly-3-hydroxybutyrate (PHB...... structural related mechanical properties.......) block covalently bonded with poly-3-hydroxyhexanoate (PHHx) block were for the first time produced successfully by a recombinant Pseudomonas putida KT2442 with its β-oxidation cycle deleted to its maximum. RESULTS: The chloroform extracted polymers were characterized by nuclear magnetic resonance (NMR...

  16. Effects of age and fasting on gluconeogenesis from glycerol in dogs.

    Science.gov (United States)

    Hall, S E; Hall, A J; Layberry, R A; Berman, M; Hetenyi, G

    1976-02-01

    The extent of gluconeogenesis from glycerol was examined in pups and adult dogs. With use of the SAAM-26 program, a four compartment model was formulated from tracer data to calculate the kinetics of the glycerol:glucose system. In the postabsorptive state gluconeogenesis from glycerol declines with age: 13.8% of glucose carbon originated from glycerol in 0- to 4-day-old pups, 6% in adults. Approximately 50% of glycerol carbon is converted to glucose carbon independent of age. During fasting, a) the percentage of glucose carbon arising from glycerol carbon increased to 13.3% and 10.3% in adult dogs and pups 5-19 days old, respectively, in younger pups it declined to 3.4%; b) glycerol production increased in adults, but decreased in the youngest pups; c) glucose production and utilization decreased at all ages, and a smaller percentage of glycerol carbon was converted to glucose carbon, especially in the youngest pups. Thus in neonates fasting decreases gluconeogenesis from glycerol.

  17. Effects of visceral adiposity on glycerol pathways in gluconeogenesis.

    Science.gov (United States)

    Neeland, Ian J; Hughes, Connor; Ayers, Colby R; Malloy, Craig R; Jin, Eunsook S

    2017-02-01

    To determine the feasibility of using oral 13 C labeled glycerol to assess effects of visceral adiposity on gluconeogenic pathways in obese humans. Obese (BMI ≥30kg/m 2 ) participants without type 2 diabetes underwent visceral adipose tissue (VAT) assessment and stratification by median VAT into high VAT-fasting (n=3), low VAT-fasting (n=4), and high VAT-refed (n=2) groups. Participants ingested [U- 13 C 3 ] glycerol and blood samples were subsequently analyzed at multiple time points over 3h by NMR spectroscopy. The fractions of plasma glucose (enrichment) derived from [U- 13 C 3 ] glycerol via hepatic gluconeogenesis, pentose phosphate pathway (PPP), and tricarboxylic acid (TCA) cycle were assessed using 13 C NMR analysis of glucose. Mixed linear models were used to compare 13 C enrichment in glucose between groups. Mean age, BMI, and baseline glucose were 49years, 40.1kg/m 2 , and 98mg/dl, respectively. Up to 20% of glycerol was metabolized in the TCA cycle prior to gluconeogenesis and PPP activity was minor (gluconeogenesis from glycerol in obese humans. Our findings provide preliminary evidence that excess visceral fat disrupts multiple pathways in hepatic gluconeogenesis from glycerol. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. The structures of Alcaligenes faecalis D-3-hydroxybutyrate dehydrogenase before and after NAD+ and acetate binding suggest a dynamical reaction mechanism as a member of the SDR family.

    Science.gov (United States)

    Hoque, Md Mominul; Shimizu, Satoru; Hossain, Md Tofazzal; Yamamoto, Tamotsu; Imamura, Shigeyuki; Suzuki, Kaoru; Tsunoda, Masaru; Amano, Hitoshi; Sekiguchi, Takeshi; Takénaka, Akio

    2008-05-01

    D-3-Hydroxybutyrate dehydrogenase, which catalyzes the reversible reaction between D-3-hydroxybutyrate and acetoacetate, has been classified into the short-chain dehydrogenase/reductase family and is a useful marker in the assay of diabetes mellitus and/or ketoacidosis. The enzyme from Alcaligenes faecalis was crystallized in the apo form and in the holo form with acetate as a substrate analogue. The crystal structures of both forms were determined at 2.2 angstroms resolution. The enzyme is a tetramer composed of four subunits assembled with noncrystallographic 222 point symmetry. Each subunit has two domains. The principal domain adopts the Rossmann fold essential for nucleotide binding, which is a common feature of the SDR family. NAD+ is bound in a large cleft in the domain. The pyrophosphate group of NAD+ is covered by the small additional domain, which is supported by two extended arms allowing domain movement. In the catalytic site, a water molecule is trapped by the catalytic Tyr155 and Ser142 residues in the vicinity of the bound NAD+ and acetate. The substrate analogue acetate is bound above the nicotinamide plane. A substrate (D-3-hydroxybutylate) bound model can reasonably be constructed by adding two C atoms into the void space between the water O atom and the methyl group of the acetate, suggesting a substrate-bound state before enzymatic reaction occurs. Based on these structural features, a reaction mechanism has been proposed.

  19. Glycerol-induced hyperhydration

    Science.gov (United States)

    Riedesel, Marvin L.; Lyons, Timothy P.; Mcnamara, M. Colleen

    1991-01-01

    Maintenance of euhydration is essential for maximum work performance. Environments which induce hypohydration reduce plasma volume and cardiovascular performance progressively declines as does work capacity. Hyperhydration prior to exposure to dehydrating environments appears to be a potential countermeasure to the debilitating effects of hypohydration. The extravascular fluid space, being the largest fluid compartment in the body, is the most logical space by which significant hyperhydration can be accomplished. Volume and osmotic receptors in the vascular space result in physiological responses which counteract hyperhydration. Our hypothesis is that glycerol-induced hyperhydration (GIH) can accomplish extravascular fluid expansion because of the high solubility of glycerol in lipid and aqueous media. A hypertonic solution of glycerol is rapidly absorbed from the gastrointestinal tract, results in mild increases in plasma osmolality and is distributed to 65 percent of the body mass. A large volume of water ingested within minutes after glycerol intake results in increased total body water because of the osmotic action and distribution of glycerol. The resulting expanded extravascular fluid space can act as a reservoir to maintain plasma volume during exposure to dehydrating environments. The fluid shifts associated with exposure to microgravity result in increased urine production and is another example of an environment which induces hypohydration. Our goal is to demonstrate that GIH will facilitate maintenance of euhydration and cardiovascular performance during space flight and upon return to a 1 g environment.

  20. Application of protease-hydrolyzed whey as a complex nitrogen source to increase poly(3-hydroxybutyrate) production from oils by Cupriavidus necator.

    Science.gov (United States)

    Obruca, Stanislav; Benesova, Pavla; Oborna, Jana; Marova, Ivana

    2014-04-01

    Whole whey hydrolyzed by Alcalase (WWH) was tested as a complex nitrogen source for the production of poly(3-hydroxybutyrate) (PHB) from waste frying oils by Cupriavidus necator H16. Addition of WWH (10 % (v/v) of cultivation media) supported the growth and PHB accumulation; PHB yields in Erlenmeyer flasks were more than 3.5-fold higher than in control cultivations. The positive influence of WWH on PHB production was confirmed in experiments performed in laboratory fermentor. C. necator cultivated with WWH produced 28.1 g PHB l(-1) resulting in a very high product yield coefficient of 0.94 g PHB per g oil. Since PHB yields were ~40 % higher than in the control cultivation, WWH can be considered as an excellent inexpensive nitrogen source for PHB production by C. necator.

  1. Biocomposite coatings based on Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/calcium phosphates obtained by MAPLE for bone tissue engineering

    Science.gov (United States)

    Raşoga, O.; Sima, L.; Chiriţoiu, M.; Popescu-Pelin, G.; Fufǎ, O.; Grumezescu, V.; Socol, M.; Stǎnculescu, A.; Zgurǎ, I.; Socol, G.

    2017-09-01

    The aim of our research was to synthesize and investigate the physico-chemical and biological features of composite coatings based on poly(3-hydroxybutyrate-co-hydroxyvalerate) (PHBV) and commercial calcium phosphates (CaPs), hydroxyapatite and β-tricalcium phosphate, obtained by means of matrix assisted pulsed laser evaporation (MAPLE) technique. In this respect, laser fluence and dropcast studies were performed for pristine polymer and PHBV-CaPs composites. The microstructure of the synthesized coatings was investigated by scanning electron microscopy, while for the chemical structure and functional integrity we performed Fourier transform infrared spectroscopy comparative analysis. By using the X-ray diffraction measurements we experimentally evaluated the crystalline nature of the obtained composite materials, while relevant data regarding the hydrophilic/hydrophobic behavior of the synthesized coatings were obtained by performing static CA measurements. The biocompatibility of PHBV/CaPs coatings was evaluated by performing cellular adhesion and differentiation in vitro assays on mesenchymal stem cells.

  2. Inactivation of an intracellular poly-3-hydroxybutyrate depolymerase of Azotobacter vinelandii allows to obtain a polymer of uniform high molecular mass.

    Science.gov (United States)

    Adaya, Libertad; Millán, Modesto; Peña, Carlos; Jendrossek, Dieter; Espín, Guadalupe; Tinoco-Valencia, Raunel; Guzmán, Josefina; Pfeiffer, Daniel; Segura, Daniel

    2018-03-01

    A novel poly-3-hydroxybutyrate depolymerase was identified in Azotobacter vinelandii. This enzyme, now designated PhbZ1, is associated to the poly-3-hydroxybutyrate (PHB) granules and when expressed in Escherichia coli, it showed in vitro PHB depolymerizing activity on native or artificial PHB granules, but not on crystalline PHB. Native PHB (nPHB) granules isolated from a PhbZ1 mutant had a diminished endogenous in vitro hydrolysis of the polyester, when compared to the granules of the wild-type strain. This in vitro degradation was also tested in the presence of free coenzyme A. Thiolytic degradation of the polymer was observed in the nPHB granules of the wild type, resulting in the formation of 3-hydroxybutyryl-CoA, but was absent in the granules of the mutant. It was previously reported that cultures of A. vinelandii OP grown in a bioreactor showed a decrease in the weight average molecular weight (Mw) of the PHB after 20 h of culture, with an increase in the fraction of polymers of lower molecular weight. This decrease was correlated with an increase in the PHB depolymerase activity during the culture. Here, we show that in the phbZ1 mutant, neither the decrease in the Mw nor the appearance of a low molecular weight polymers occurred. In addition, a higher PHB accumulation was observed in the cultures of the phbZ1 mutant. These results suggest that PhbZ1 has a role in the degradation of PHB in cultures in bioreactors and its inactivation allows the production of a polymer of a uniform high molecular weight.

  3. Enzymatic Synthesis of a Bio-Based Copolyester from Poly(butylene succinate) and Poly((R)-3-hydroxybutyrate): Study of Reaction Parameters on the Transesterification Rate.

    Science.gov (United States)

    Debuissy, Thibaud; Pollet, Eric; Avérous, Luc

    2016-12-12

    The enzyme-catalyzed synthesis of fully biobased poly(3-hydroxybutyrate-co-butylene succinate) (poly(HB-co-BS)) copolyesters is reported for the first time. Different Candida antarctica lipase B (CALB)-catalyzed copolyesters were produced in solution, via a one-step or a two-step process from 1,4-butanediol, diethyl succinate, and synthesized telechelic hydroxylated poly(3-hydroxybutyrate) oligomers (PHB-diol). The influence of the ester/hydroxyl functionality ratio, catalyst amount, PHB-diol oligomer chain length, hydroxybutyrate (HB) and butylene succinate (BS) contents, and the nature of the solvent were investigated. The two-step process allowed the synthesis of copolyesters of high molar masses (M n up to 18 000 g/mol), compared to the one-step process (M n ∼ 8000 g/mol), without thermal degradation. The highest molar masses were obtained with diphenyl ether as solvent, compared with dibenzyl ether or anisole. During the two-step process, the transesterification rate between the HB and BS segments (i) increased with increasing amount of catalyst and decreasing molar mass of the PHB-diol oligomer, (ii) decreased when anisole was used as the solvent, and (iii) was not influenced by the HB/BS ratio. Tendencies toward block or random macromolecular architectures were observed as a function of the reaction time, the PHB-diol oligomer chain length, and the chosen solvent. Immobilized CALB-catalyzed copolyesters were thermally stable up to 200 °C. The crystalline structure of the poly(HB-co-BS) copolyesters depended on the HB/BS ratio and the average sequence length of the segments. The crystalline content, T m and T c decreased with increasing HB content and the randomness of the copolymer structure.

  4. Synthesis of Diblock copolymer poly-3-hydroxybutyrate -block-poly-3-hydroxyhexanoate [PHB-b-PHHx] by a β-oxidation weakened Pseudomonas putida KT2442.

    Science.gov (United States)

    Tripathi, Lakshmi; Wu, Lin-Ping; Chen, Jinchun; Chen, Guo-Qiang

    2012-04-05

    Block polyhydroxyalkanoates (PHA) were reported to be resistant against polymer aging that negatively affects polymer properties. Recently, more and more attempts have been directed to make PHA block copolymers. Diblock copolymers PHB-b-PHHx consisting of poly-3-hydroxybutyrate (PHB) block covalently bonded with poly-3-hydroxyhexanoate (PHHx) block were for the first time produced successfully by a recombinant Pseudomonas putida KT2442 with its β-oxidation cycle deleted to its maximum. The chloroform extracted polymers were characterized by nuclear magnetic resonance (NMR), thermo- and mechanical analysis. NMR confirmed the existence of diblock copolymers consisting of 58 mol% PHB as the short chain length block with 42 mol% PHHx as the medium chain length block. The block copolymers had two glass transition temperatures (Tg) at 2.7°C and -16.4°C, one melting temperature (Tm) at 172.1°C and one cool crystallization temperature (Tc) at 69.1°C as revealed by differential scanning calorimetry (DSC), respectively. This is the first microbial short-chain-length (scl) and medium-chain-length (mcl) PHA block copolymer reported. It is possible to produce PHA block copolymers of various kinds using the recombinant Pseudomonas putida KT2442 with its β-oxidation cycle deleted to its maximum. In comparison to a random copolymer poly-3-hydroxybutyrate-co-3-hydroxyhexanoate (P(HB-co-HHx)) and a blend sample of PHB and PHHx, the PHB-b-PHHx showed improved structural related mechanical properties.

  5. An improved glycerol biosensor with an Au-FeS-NAD-glycerol-dehydrogenase anode.

    Science.gov (United States)

    Mahadevan, Aishwarya; Fernando, Sandun

    2017-06-15

    An improved glycerol biosensor was developed via direct attachment of NAD + -glycerol dehydrogenase coenzyme-apoenzyme complex onto supporting gold electrodes, using novel inorganic iron (II) sulfide (FeS)-based single molecular wires. Sensing performance factors, i.e., sensitivity, a detection limit and response time of the FeS and conventional pyrroloquinoline quinone (PQQ)-based biosensor were evaluated by dynamic constant potential amperometry at 1.3V under non-buffered conditions. For glycerol concentrations ranging from 1 to 25mM, a 77% increase in sensitivity and a 53% decrease in detection limit were observed for the FeS-based biosensor when compared to the conventional PQQ-based counterpart. The electrochemical behavior of the FeS-based glycerol biosensor was analyzed at different concentrations of glycerol, accompanied by an investigation into the effects of applied potential and scan rate on the current response. Effects of enzyme stimulants ((NH 4 ) 2 SO 4 and MnCl 2 ·4H 2 O) concentrations and buffers/pH (potassium phosphate buffer pH 6-8, Tris buffer pH 8-10) on the current responses generated by the FeS-based glycerol biosensor were also studied. The optimal detection conditions were 0.03M (NH 4 ) 2 SO 4 and 0.3µm MnCl 2 ·4H 2 O in non-buffered aqueous electrolyte under stirring whereas under non-stirring, Tris buffer at pH 10 with 0.03M (NH 4 ) 2 SO 4 and 30µm MnCl 2 ·4H 2 O were found to be optimal detection conditions. Interference by glucose, fructose, ethanol, and acetic acid in glycerol detection was studied. The observations indicated a promising enhancement in glycerol detection using the novel FeS-based glycerol sensing electrode compared to the conventional PQQ-based one. These findings support the premise that FeS-based bioanodes are capable of biosensing glycerol successfully and may be applicable for other enzymatic biosensors. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Enhanced hydrogen and 1,3-propanediol production from glycerol by fermentation using mixed cultures

    KAUST Repository

    Selembo, Priscilla A.

    2009-12-15

    The conversion of glycerol into high value products, such as hydrogen gas and 1,3-propanediol (PD), was examined using anaerobic fermentation with heat-treated mixed cultures. Glycerol fermentation produced 0.28 mol-H 2/mol-glycerol (72 mL-H2/g-COD) and 0.69 mol-PD/mol-glycerol. Glucose fermentation using the same mixed cultures produced more hydrogen gas (1.06 mol-H2/mol-glucose) but no PD. Changing the source of inoculum affected gas production likely due to prior acclimation of bacteria to this type of substrate. Fermentation of the glycerol produced from biodiesel fuel production (70% glycerol content) produced 0.31 mol-H 2/mol-glycerol (43 mL H2/g-COD) and 0.59 mol-PD/mol-glycerol. These are the highest yields yet reported for both hydrogen and 1,3-propanediol production from pure glycerol and the glycerol byproduct from biodiesel fuel production by fermentation using mixed cultures. These results demonstrate that production of biodiesel can be combined with production of hydrogen and 1,3-propanediol for maximum utilization of resources and minimization of waste. © 2009 Wiley Periodicals, Inc.

  7. Rainbow smelt: the unusual case of cryoprotection by sustained glycerol production in an aquatic animal.

    Science.gov (United States)

    Driedzic, William R

    2015-07-01

    Rainbow smelt flourish at -1.8 °C, the freezing point of sea water. An antifreeze protein contributes to freeze point depression but, more importantly, cryoprotection is due to an elevation in osmotic pressure, by the accumulation of glycerol. The lower the water temperature, the higher the plasma glycerol with levels recorded as high as 400 mmol l(-1). Glycerol freely diffuses out in direct relation to the glycerol concentration and fish may lose as much as 15% of their glycerol reserve per day. Glycerol levels decrease from a maximum in February/March while water temperature is still sub-zero. The decrease in glycerol may respond to a photoperiod signal as opposed to initiation which is triggered by low temperature. The initial increase in glycerol level is supported by liver glycogen but high sustained glycerol level is dependent upon dietary carbohydrate and protein. The metabolic pathways leading to glycerol involve flux from glycogen/glucose to the level of dihydroxyacetone phosphate (DHAP) via the initial part of glycolysis and from amino acids via a truncated gluconeogenesis again to the level of DHAP. DHAP in turn is converted to glycerol 3-phosphate (G3P) and then directly to glycerol. The key to directing DHAP to G3P is a highly active glycerol 3-P dehydrogenase. G3P is converted directly to glycerol via G3P phosphatase, the rate-limiting step in the process. The transition to glycerol production is associated with increased activities of enzymes at key loci in the top part of glycogenolysis/glycolysis. Curtailment of the final section of glycolysis may reside at the level of pyruvate oxidation with an inactivation of pyruvate dehydrogenase (PDH) driven by increased levels of PDH kinase. Enzymes associated with amino acid trafficking are elevated as is the pivotal enzyme phosphoenolpyruvate carboxykinase.

  8. Hibernation impact on the catalytic activities of the mitochondrial D-3-hydroxybutyrate dehydrogenase in liver and brain tissues of jerboa (Jaculus orientalis

    Directory of Open Access Journals (Sweden)

    Hafiani Assia

    2003-09-01

    Full Text Available Abstract Background Jerboa (Jaculus orientalis is a deep hibernating rodent native to subdesert highlands. During hibernation, a high level of ketone bodies i.e. acetoacetate (AcAc and D-3-hydroxybutyrate (BOH are produced in liver, which are used in brain as energetic fuel. These compounds are bioconverted by mitochondrial D-3-hydroxybutyrate dehydrogenase (BDH E.C. 1.1.1.30. Here we report, the function and the expression of BDH in terms of catalytic activities, kinetic parameters, levels of protein and mRNA in both tissues i.e brain and liver, in relation to the hibernating process. Results We found that: 1/ In euthemic jerboa the specific activity in liver is 2.4- and 6.4- fold higher than in brain, respectively for AcAc reduction and for BOH oxidation. The same differences were found in the hibernation state. 2/ In euthermic jerboa, the Michaelis constants, KM BOH and KM NAD+ are different in liver and in brain while KM AcAc, KM NADH and the dissociation constants, KD NAD+and KD NADH are similar. 3/ During prehibernating state, as compared to euthermic state, the liver BDH activity is reduced by half, while kinetic constants are strongly increased except KD NAD+. 4/ During hibernating state, BDH activity is significantly enhanced, moreover, kinetic constants (KM and KD are strongly modified as compared to the euthermic state; i.e. KD NAD+ in liver and KM AcAc in brain decrease 5 and 3 times respectively, while KD NADH in brain strongly increases up to 5.6 fold. 5/ Both protein content and mRNA level of BDH remain unchanged during the cold adaptation process. Conclusions These results cumulatively explained and are consistent with the existence of two BDH enzymatic forms in the liver and the brain. The apoenzyme would be subjected to differential conformational folding depending on the hibernation state. This regulation could be a result of either post-translational modifications and/or a modification of the mitochondrial membrane state

  9. Insulin regulation of renal glucose metabolism in conscious dogs.

    OpenAIRE

    Cersosimo, E; Judd, R L; Miles, J M

    1994-01-01

    Previous studies indicating that postabsorptive renal glucose production is negligible used the net balance technique, which cannot partition simultaneous renal glucose production and glucose uptake. 10 d after surgical placement of sampling catheters in the left renal vein and femoral artery and a nonobstructive infusion catheter in the left renal artery of dogs, systemic and renal glucose and glycerol kinetics were measured with peripheral infusions of [3-3H]glucose and [2-14C]glycerol. Aft...

  10. Combining molecular and bioprocess techniques to produce poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with controlled monomer composition by Burkholderia sacchari.

    Science.gov (United States)

    Mendonça, Thatiane T; Tavares, Rafaela R; Cespedes, Lucas G; Sánchez-Rodriguez, Ruben J; Schripsema, Jan; Taciro, Marilda K; Gomez, José G C; Silva, Luiziana F

    2017-05-01

    Biopolymers as polyhydroxyalkanoates (PHA) composed by different co-monomers 3-hydroxybutyrate and 3-hydroxyhexanoate [P(3HB-co-3HHx)] has attracted interest since its properties are similar to low density polyethylene. Burkholderia sacchari produces this copolymer with a very low 3HHx molar fraction, about 2 mol%. B. sacchari mutant (unable to produce polymer) was engineered to host PHA biosynthesis genes (phaPCJ) from Aeromonas sp. In addition, a two-step bioprocess to increase biopolymer production was developed. The combination of these techniques resulted in the production of P(3HB-co-3HHx) with 3HHx content up to 20 mol%. The PHA content was about 78% of dry biomass, resulting in PHA volumetric productivities around 0.45gl -1 h -1 . The P(3HB-co-3HHx) containing 20 mol% of 3HHx presented an elongation at brake of 945%, higher than reported before for this PHA composition. Here we have described an approach to increase 3HHx content into the copolymer, allowing the precise control of the 3HHx molar fractions. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Application of acetyl-CoA acetyltransferase (AtoAD) in Escherichia coli to increase 3-hydroxyvalerate fraction in poly(3-hydroxybutyrate-co-3-hydroxyvalerate).

    Science.gov (United States)

    Jeon, Jong-Min; Kim, Hyun-Joong; Bhatia, Shashi Kant; Sung, Changmin; Seo, Hyung-Min; Kim, Jung-Ho; Park, Hyung-Yeon; Lee, Dahye; Brigham, Christopher J; Yang, Yung-Hun

    2017-05-01

    Polyhydroxyalkanoate (PHA) is a family of biodegradable polymers, and incorporation of different monomers can alter its physical properties. To produce the copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)) containing a high level of 3-hydroxyvalerate (3HV) by altering acetyl-CoA pool levels, we overexpressed an acetyl-CoA acetyltransferase (atoAD) in an engineered E. coli strain, YH090, carrying PHA synthetic genes bktB, phaB, and phaC. It was found that, with introduction of atoAD and with propionate as a co-substrate, 3HV fraction in PHA was increased up to 7.3-fold higher than a strain without atoAD expressed in trans (67.9 mol%). By the analysis of CoA pool concentrations in vivo and in vitro using HPLC and LC-MS, overexpression of AtoAD was shown to decrease the amount of acetyl-CoA and increase the propionyl-CoA/acetyl-CoA ratio, ultimately resulting in an increased 3HV fraction in PHA. Finally, synthesis of P(3HB-co-3HV) containing 57.9 mol% of 3HV was achieved by fed-batch fermentation of YJ101 with propionate.

  12. The ntrB and ntrC Genes Are Involved in the Regulation of Poly-3-Hydroxybutyrate Biosynthesis by Ammonia in Azospirillum brasilense Sp7

    Science.gov (United States)

    Sun, Jun; Peng, Xuan; Van Impe, Jan; Vanderleyden, Jos

    2000-01-01

    Azospirillum brasilense Sp7 and its ntrA (rpoN), ntrBC, and ntrC mutants have been evaluated for their capabilities of poly-3-hydroxybutyrate (PHB) accumulation in media with high and low ammonia concentrations. It was observed that the ntrBC and ntrC mutants can produce PHB in both low- and high-C/N-ratio media, while no significant PHB production was observed for the wild type or the ntrA mutant in low-C/N-ratio media. Further investigation by fermentation analysis indicated that the ntrBC and ntrC mutants were able to grow and accumulate PHB simultaneously in the presence of a high concentration of ammonia in the medium, while little PHB was produced in the wild type and ntrA (rpoN) mutant during active growth phase. These results provide the first genetic evidence that the ntrB and ntrC genes are involved in the regulation of PHB synthesis by ammonia in A. brasilense Sp7. PMID:10618211

  13. Cloning of the Nocardia corallina polyhydroxyalkanoate synthase gene and production of poly-(3-hydroxybutyrate-co-3-hydroxyhexanoate) and poly-(3-hydroxyvalerate-co-3-hydroxyheptanoate).

    Science.gov (United States)

    Hall, B; Baldwin, J; Rhie, H G; Dennis, D

    1998-07-01

    The polyhydroxyalkanoate (PHA) synthase gene (phaCNc) from Nocardia corallina was identified in a lambda library on a 6-kb BamHI fragment. A 2.8-kb XhoII subfragment was found to contain the intact PHA synthase. This 2.8-kb fragment was subjected to DNA sequencing and was found to contain the coding region for the PHA synthase and a small downstream open reading frame of unknown function. On the basis of DNA sequence, phaCNc is closest in homology to the PHA synthases (phaCPaI and phaCPaII) of Pseudomonas aeruginosa (approximately 41% identity and 55% similarity). The 2.8-kb XhoII fragment containing phaCNc was subcloned into broad host range mobilizable plasmids and transferred into Escherichia coli, Klebsiella aerogenes (both containing a plasmid bearing phaA and phaB from Ralstonia eutropha), and PHA-negative strains of R. eutropha and Pseudomonas putida. The recombinant strains were grown on various carbon sources and the resulting polymers were analyzed. In these strains, the PHA synthase from N. corallina was able to mediate the production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) containing high levels of 3-hydroxyhexanoate when grown on hexanoate and larger even-chain fatty acids and poly(3-hydroxyvalerate-co-3-hydroxyheptanoate) containing high levels of 3-hydroxyheptanoate when grown on heptanoate or larger odd-chain fatty acids.

  14. Release of the Diclofenac Sodium by Nanofibers of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate Obtained from Electrospinning and Solution Blow Spinning

    Directory of Open Access Journals (Sweden)

    Michelle Andrade Souza

    2014-01-01

    Full Text Available Electrospun fibers are explored as a new system for controlled drug delivery. Novel techniques capable of obtaining polymer nanofibers have been reported in the literature. They include solution blow spinning (SBS, which is a technique to produce polymer nanofibers in the same range as electrospinning, using pressurized gas instead of high voltage. The present study investigates release characteristics of diclofenac sodium encapsulated at three concentrations (5, 10, and 20% w/v in poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV nanofibers made by electrospinning and SBS and determines the drug’s effect on fiber morphology and structural properties. PHBV nanofibers were characterized using scanning electronic microscopy, differential scanning calorimetry, and X-ray diffraction, and the release profile was examined via UV-Vis spectrophotometry. Both electrospinning and SBS encapsulated diclofenac sodium in PHBV membranes efficiently and effectively. The profile of the in vitro release of diclofenac sodium was dependent on drug concentration and temperature. The drug reduced crystallinity and increased flexibility.

  15. Structural and morphological studies on poly(3-hydroxybutyrate acid) (PHB)/chitosan drug releasing microspheres prepared by both single and double emulsion processes

    Energy Technology Data Exchange (ETDEWEB)

    Shih, W.-J. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Chen, Y.-H. [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-kung Road, Kaohsiung 80782, Taiwan (China); Shih, C.-J. [Faculty of Fragrance and Cosmetics, Kaohsiung Medical University, No. 100, Shih-Chuang 1st Rd., Sanmin District, Kaohsiung 80708, Taiwan (China); Hon, M.-H. [Department of Materials Science and Engineering, National Cheng Kung University, 1 Ta-Hsueh Road, Tainan 70101, Taiwan (China); Dayeh University, 112 Shan-Jiau Road, Da-Tsuen, Changhua 515, Taiwan (China); Wang, M.-C. [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, 415 Chien-kung Road, Kaohsiung 80782, Taiwan (China) and Department of Materials Science and Engineering, National United University, 1 Lien-Da Road, Kung-ching Li, Miao Li 360, Taiwan (China)]. E-mail: mcwang@cc.kuas.edu.tw

    2007-05-31

    Drug releasing microspheres of poly(3-hydroxybutyric acid)/chitosan (PHB/CTS) with various compositions have been synthesized by both single and double emulsion methods, and collected by a freeze-drying process. In this study, gentamicin was used as an antibacterial medicine coated with PHB. The PHB/CTS microspheres of various compositions prepared by a single emulsion process (SEP) were identified as the major PHB phase together with a minor unknown Phase X by X-ray diffraction (XRD) and FT-IR. However, in the microspheres prepared using a double emulsion process (DEP) the dominant Phase was X and the minor phase was PHB. The size of the PHB/CTS microspheres prepared by SEP increased with the PHB/CTS ratio from 1 {mu}m for 1:1 to 2 {mu}m for 5:1. However, the size of the PHB/CTS microspheres prepared by DEP decreased with the PHB/CTS ratio from 1 {mu}m for 1:1 to 800 nm for 5:1.

  16. Structural and morphological studies on poly(3-hydroxybutyrate acid) (PHB)/chitosan drug releasing microspheres prepared by both single and double emulsion processes

    International Nuclear Information System (INIS)

    Shih, W.-J.; Chen, Y.-H.; Shih, C.-J.; Hon, M.-H.; Wang, M.-C.

    2007-01-01

    Drug releasing microspheres of poly(3-hydroxybutyric acid)/chitosan (PHB/CTS) with various compositions have been synthesized by both single and double emulsion methods, and collected by a freeze-drying process. In this study, gentamicin was used as an antibacterial medicine coated with PHB. The PHB/CTS microspheres of various compositions prepared by a single emulsion process (SEP) were identified as the major PHB phase together with a minor unknown Phase X by X-ray diffraction (XRD) and FT-IR. However, in the microspheres prepared using a double emulsion process (DEP) the dominant Phase was X and the minor phase was PHB. The size of the PHB/CTS microspheres prepared by SEP increased with the PHB/CTS ratio from 1 μm for 1:1 to 2 μm for 5:1. However, the size of the PHB/CTS microspheres prepared by DEP decreased with the PHB/CTS ratio from 1 μm for 1:1 to 800 nm for 5:1

  17. Antimicrobial and cell viability measurement of bovine serum albumin capped silver nanoparticles (Ag/BSA) loaded collagen immobilized poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) film.

    Science.gov (United States)

    Bakare, Rotimi; Hawthrone, Samantha; Vails, Carmen; Gugssa, Ayele; Karim, Alamgir; Stubbs, John; Raghavan, Dharmaraj

    2016-03-01

    Bacterial infection of orthopedic devices has been a major concern in joint replacement procedures. Therefore, this study is aimed at formulating collagen immobilized poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) film loaded with bovine serum albumin capped silver nanoparticles (Ag/BSA NPs) to inhibit bacterial growth while retaining/promoting osteoblast cells viability. The nanoparticles loaded collagen immobilized PHBV film was characterized for its composition by X-ray Photoelectron Spectroscopy and Anodic Stripping Voltammetry. The extent of loading of Ag/BSA NPs on collagen immobilized PHBV film was found to depend on the chemistry of the functionalized PHBV film and the concentration of Ag/BSA NPs solution used for loading nanoparticles. Our results showed that more Ag/BSA NPs were loaded on higher molecular weight collagen immobilized PHEMA-g-PHBV film. Maximum loading of Ag/BSA NPs on collagen immobilized PHBV film was observed when 16ppm solution was used for adsorption studies. Colony forming unit and optical density measurements showed broad antimicrobial activity towards Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa at significantly lower concentration i.e., 0.19 and 0.31μg/disc, compared to gentamicin and sulfamethoxazole trimethoprim while MTT assay showed that released nanoparticles from Ag/BSA NPs loaded collagen immobilized PHBV film has no impact on MCTC3-E1 cells viability. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Conductive PEDOT:PSS coated polylactide (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) electrospun membranes: Fabrication and characterization.

    Science.gov (United States)

    Chang, Hui Chung; Sun, Tao; Sultana, Naznin; Lim, Mim Mim; Khan, Tareef Hayat; Ismail, Ahmad Fauzi

    2016-04-01

    In the current study, electrospinning technique was used to fabricate composite membranes by blending of a synthetic polymer, polylactic acid (PLA) and a natural polymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV. Conductive membranes were prepared by dipping PLA/PHBV electrospun membranes into poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) ( PSS) solution, which is a biocompatible polymer. The coated and uncoated membranes were evaluated using several techniques. The electrical conductivity of the coated membranes was measured using a digital multimeter. In vitro cell cytotoxicity and cell viability were measured by culturing human skin fibroblast (HSF) cells onto the membranes using MTT assays. It was observed that electrospinning of 20% (w/v) PLA/PHBV with a weight ratio of 50:50 produced the most uniform fibers with no beads. It was observed that the wettability and surface roughness of the PSS coated PLA/PHBV membranes were greatly increased than uncoated membrane. The results of cell viability using MTT assay, cell attachment and cell proliferation showed that the conductive PSS coated PLA/PHBV membrane were more favorable for tissue engineering application than their uncoated counterparts. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Conductive PEDOT:PSS coated polylactide (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) electrospun membranes: Fabrication and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Hui Chung [Faculty of Bioscience and Medical Engineering, Universiti Teknologi Malaysia, 81300, Johor (Malaysia); Sun, Tao [Miniaturized Medical Devices Program, Institute of Microelectronics, Agency for Science, Technology and Research - A*STAR (Singapore); Sultana, Naznin, E-mail: naznin@biomedical.utm.my [Faculty of Bioscience and Medical Engineering, Universiti Teknologi Malaysia, 81300, Johor (Malaysia); Advanced Membrane Technology Research Center, Universiti Teknologi Malaysia, 81300, Johor (Malaysia); Lim, Mim Mim [Faculty of Bioscience and Medical Engineering, Universiti Teknologi Malaysia, 81300, Johor (Malaysia); Khan, Tareef Hayat [KALAM, Faculty of Alam Bina, Universiti Teknologi Malaysia, 81300, Johor (Malaysia); Ismail, Ahmad Fauzi [Advanced Membrane Technology Research Center, Universiti Teknologi Malaysia, 81300, Johor (Malaysia)

    2016-04-01

    In the current study, electrospinning technique was used to fabricate composite membranes by blending of a synthetic polymer, polylactic acid (PLA) and a natural polymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV. Conductive membranes were prepared by dipping PLA/PHBV electrospun membranes into poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonate) (PEDOT:PSS) solution, which is a biocompatible polymer. The coated and uncoated membranes were evaluated using several techniques. The electrical conductivity of the coated membranes was measured using a digital multimeter. In vitro cell cytotoxicity and cell viability were measured by culturing human skin fibroblast (HSF) cells onto the membranes using MTT assays. It was observed that electrospinning of 20% (w/v) PLA/PHBV with a weight ratio of 50:50 produced the most uniform fibers with no beads. It was observed that the wettability and surface roughness of the PEDOT:PSS coated PLA/PHBV membranes were greatly increased than uncoated membrane. The results of cell viability using MTT assay, cell attachment and cell proliferation showed that the conductive PEDOT:PSS coated PLA/PHBV membrane were more favorable for tissue engineering application than their uncoated counterparts. - Highlights: • Coating with PEDOT:PSS increased the wettability of PLA/PHBV membrane. • PEDOT:PSS rendered the PLA/PHBV membrane conductive. • PEDOT:PSS coated PLA/PHBV had significantly higher cell attachment.

  20. Conductive PEDOT:PSS coated polylactide (PLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) electrospun membranes: Fabrication and characterization

    International Nuclear Information System (INIS)

    Chang, Hui Chung; Sun, Tao; Sultana, Naznin; Lim, Mim Mim; Khan, Tareef Hayat; Ismail, Ahmad Fauzi

    2016-01-01

    In the current study, electrospinning technique was used to fabricate composite membranes by blending of a synthetic polymer, polylactic acid (PLA) and a natural polymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), PHBV. Conductive membranes were prepared by dipping PLA/PHBV electrospun membranes into poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonate) (PEDOT:PSS) solution, which is a biocompatible polymer. The coated and uncoated membranes were evaluated using several techniques. The electrical conductivity of the coated membranes was measured using a digital multimeter. In vitro cell cytotoxicity and cell viability were measured by culturing human skin fibroblast (HSF) cells onto the membranes using MTT assays. It was observed that electrospinning of 20% (w/v) PLA/PHBV with a weight ratio of 50:50 produced the most uniform fibers with no beads. It was observed that the wettability and surface roughness of the PEDOT:PSS coated PLA/PHBV membranes were greatly increased than uncoated membrane. The results of cell viability using MTT assay, cell attachment and cell proliferation showed that the conductive PEDOT:PSS coated PLA/PHBV membrane were more favorable for tissue engineering application than their uncoated counterparts. - Highlights: • Coating with PEDOT:PSS increased the wettability of PLA/PHBV membrane. • PEDOT:PSS rendered the PLA/PHBV membrane conductive. • PEDOT:PSS coated PLA/PHBV had significantly higher cell attachment.

  1. Post-processing optimization of electrospun submicron poly(3-hydroxybutyrate) fibers to obtain continuous films of interest in food packaging applications.

    Science.gov (United States)

    Cherpinski, Adriane; Torres-Giner, Sergio; Cabedo, Luis; Lagaron, Jose M

    2017-10-01

    Polyhydroxyalkanoates (PHAs) are one of the most researched family of biodegradable polymers based on renewable materials due to their thermoplastic nature and moisture resistance. The present study was targeted to investigate the preparation and characterization of poly(3-hydroxybutyrate) (PHB) films obtained through the electrospinning technique. To convert them into continuous films and then to increase their application interest in packaging, the electrospun fiber mats were subsequently post-processed by different physical treatments. Thus, the effect of annealing time and cooling method on morphology, molecular order, thermal, optical, mechanical, and barrier properties of the electrospun submicron PHB fibers was studied. Annealing at 160°C, well below the homopolyester melting point, was found to be the minimum temperature at which homogeneous transparent films were produced. The film samples that were cooled slowly after annealing showed the lowest permeability to oxygen, water vapor, and limonene. The optimally post-processed electrospun PHB fibers exhibited similar rigidity to conventional compression-molded PHA films, but with enhanced elongation at break and toughness. Films made by this electrospinning technique have many potential applications, such as in the design of barrier layers, adhesive interlayers, and coatings for fiber- and plastic-based food packaging materials.

  2. Environmentally Friendly Compatibilizers from Soybean Oil for Ternary Blends of Poly(lactic acid-PLA, Poly(ε-caprolactone-PCL and Poly(3-hydroxybutyrate-PHB

    Directory of Open Access Journals (Sweden)

    María Jesús Garcia-Campo

    2017-11-01

    Full Text Available Ternary blends of poly(lactic acid (PLA, poly(3-hydroxybutyrate (PHB and poly(ε-caprolactone (PCL with a constant weight percentage of 60%, 10% and 30% respectively were compatibilized with soybean oil derivatives epoxidized soybean oil (ESO, maleinized soybean oil (MSO and acrylated epoxidized soybean oil (AESO. The potential compatibilization effects of the soybean oil-derivatives was characterized in terms of mechanical, thermal and thermomechanical properties. The effects on morphology were studied by field emission scanning electron microscopy (FESEM. All three soybean oil-based compatibilizers led to a noticeable increase in toughness with a remarkable improvement in elongation at break. On the other hand, both the tensile modulus and strength decreased, but in a lower extent to a typical plasticization effect. Although phase separation occurred, all three soybean oil derivatives led somewhat to compatibilization through reaction between terminal hydroxyl groups in all three biopolyesters (PLA, PHB and PCL and the readily reactive groups in the soybean oil derivatives, that is, epoxy, maleic anhydride and acrylic/epoxy functionalities. In particular, the addition of 5 parts per hundred parts of the blend (phr of ESO gave the maximum elongation at break while the same amount of MSO and AESO gave the maximum toughness, measured through Charpy’s impact tests. In general, the herein-developed materials widen the potential of ternary PLA formulations by a cost effective blending method with PHB and PCL and compatibilization with vegetable oil-based additives.

  3. Poly-3-hydroxybutyrate (PHB) production from alkylphenols, mono and poly-aromatic hydrocarbons using Bacillus sp. CYR1: A new strategy for wealth from waste.

    Science.gov (United States)

    Venkateswar Reddy, M; Mawatari, Yasuteru; Yajima, Yuka; Seki, Chigusa; Hoshino, Tamotsu; Chang, Young-Cheol

    2015-09-01

    In the present study five different types of alkylphenols, each of the two different types of mono and poly-aromatic hydrocarbons were selected for degradation, and conversion into poly-3-hydroxybutyrate (PHB) using the Bacillus sp. CYR1. Strain CYR1 showed growth with various toxic organic compounds. Degradation pattern of all the organic compounds at 100 mg/l concentration with or without addition of tween-80 were analyzed using high pressure liquid chromatography (HPLC). Strain CYR1 showed good removal of compounds in the presence of tween-80 within 3 days, but it took 6 days without addition of tween-80. Strain CYR1 showed highest PHB production with phenol (51 ± 5%), naphthalene (42 ± 4%), 4-chlorophenol (32 ± 3%) and 4-nonylphenol (29 ± 3%). The functional groups, structure, and thermal properties of the produced PHB were analyzed. These results denoted that the strain Bacillus sp. CYR1 can be used for conversion of different toxic compounds persistent in wastewaters into useable biological polyesters. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Selected ion flow tube mass spectrometry of 3-hydroxybutyric acid, acetone and other ketones in the headspace of aqueous solution and urine

    Science.gov (United States)

    Wang, Tianshu; Spanel, Patrik; Smith, David

    2008-04-01

    A study has been carried out of the reactions of three isomers of hydroxybutyric acid, giving special attention to 3-hydroxybutyric acid, 3-HBA, with H3O+ and NO+ ions to acquire the required kinetic data for a selected ion flow tube mass spectrometry, SIFT-MS, search for 3-HBA in the headspace of urine since it is known to be one of the "ketone bodies" important in the diagnosis of ketoacidosis. Thus, the product ions formed in the reactions of the H3O+ and NO+ precursor ions with the three hydroxy acids were established by sampling the headspace above the pure compounds over a range of absolute humidities from 1.5% (ambient air) to 6% (liquid headspace at 37 C and exhaled breath). Then these data, together with the rate coefficients for the reactions estimated by calculation, were used to detect and quantify 3-HBA in the headspace of an aqueous solution of this compound of known concentration and above urine donated by two volunteers. The level of 3-HBA above the urine samples after they were acidified with hydrochloric acid was seen to be typically 40 parts-per-billion, ppb, which is much lower than that for acetone seen to be typically 800 ppb. Exploiting the aqueous solution data as a reference, the 3-HBA concentration in the urine samples was estimated to be about 1-2 mmol/L, which is typical of the urine from healthy individuals.

  5. Improved glycerol utilization by a triacylglycerol-producing Rhodococcus opacus strain for renewable fuels.

    Science.gov (United States)

    Kurosawa, Kazuhiko; Radek, Andreas; Plassmeier, Jens K; Sinskey, Anthony J

    2015-01-01

    Glycerol generated during renewable fuel production processes is potentially an attractive substrate for the production of value-added materials by fermentation. An engineered strain MITXM-61 of the oleaginous bacterium Rhodococcus opacus produces large amounts of intracellular triacylglycerols (TAGs) for lipid-based biofuels on high concentrations of glucose and xylose. However, on glycerol medium, MITXM-61 does not produce TAGs and grows poorly. The aim of the present work was to construct a TAG-producing R. opacus strain capable of high-cell-density cultivation at high glycerol concentrations. An adaptive evolution strategy was applied to improve the conversion of glycerol to TAGs in R. opacus MITXM-61. An evolved strain, MITGM-173, grown on a defined medium with 16 g L(-1) glycerol, produced 2.3 g L(-1) of TAGs, corresponding to 40.4% of the cell dry weight (CDW) and 0.144 g g(-1) of TAG yield per glycerol consumed. MITGM-173 was able to grow on high concentrations (greater than 150 g L(-1)) of glycerol. Cultivated in a medium containing an initial concentration of 20 g L(-1) glycerol, 40 g L(-1) glucose, and 40 g L(-1) xylose, MITGM-173 was capable of simultaneously consuming the mixed substrates and yielding 13.6 g L(-1) of TAGs, representing 51.2% of the CDM. In addition, when 20 g L(-1) glycerol was pulse-loaded into the culture with 40 g L(-1) glucose and 40 g L(-1) xylose at the stationary growth phase, MITGM-173 produced 14.3 g L(-1) of TAGs corresponding to 51.1% of the CDW although residual glycerol in the culture was observed. The addition of 20 g L(-1) glycerol in the glucose/xylose mix resulted in a TAG yield per glycerol consumed of 0.170 g g(-1) on the initial addition and 0.279 g g(-1) on the pulse addition of glycerol. We have generated a TAG-producing R. opacus MITGM-173 strain that shows significantly improved glycerol utilization in comparison to the parental strain. The present study demonstrates that the

  6. Crystal structures, thermal behaviors, and C-H...O=C hydrogen bondings of poly(3-hydroxyvalerate) and poly(3-hydroxybutyrate) studied by infrared spectroscopy and X-ray diffraction

    Czech Academy of Sciences Publication Activity Database

    Sato, H.; Ando, Y.; Dybal, Jiří; Iwata, T.; Noda, I.; Ozaki, Y.

    2008-01-01

    Roč. 41, č. 12 (2008), s. 4305-4312 ISSN 0024-9297 R&D Projects: GA ČR GA203/05/0425 Grant - others:Ministry of Education, Culture, Sports , Science and Technology (JP) MEXT Institutional research plan: CEZ:AV0Z40500505 Keywords : poly(3-hydroxyvalerate) * poly(3-hydroxybutyrate) * infrared spectroscopy Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.407, year: 2008

  7. Establishment of a two-dimensional chiral HPLC system for the simultaneous detection of lactate and 3-hydroxybutyrate enantiomers in human clinical samples.

    Science.gov (United States)

    Liu, Shu-Ling; Oyama, Tsubasa; Miyoshi, Yurika; Sheu, Shiow-Yunn; Mita, Masashi; Ide, Tomomi; Lindner, Wolfgang; Hamase, Kenji; Lee, Jen-Ai

    2015-12-10

    A two-dimensional chiral high-performance liquid chromatography system was established for simultaneous detection of lactate (LA) and 3-hydroxybutyrate (3HB) enantiomers in human clinical samples. d-LA is increased upon kidney damage but 3HB protected against kidney injury. Therefore, determining the concentrations of D,L-LA and D,L-3HB simultaneously would be useful for evaluating pathological conditions. LA and 3HB were pre-column-derivatized with the fluorescent reagent 4-(N-chloroformylmethyl-N-methylamino)-7-nitro-2,1,3-benzoxadiazole (NBD-COCl) at 60 °C for 15 min and separated in the first dimension with a capillary monolithic octadecylsilane column. The mobile phase consisted of 13% acetonitrile and 0.05% tirfluoroacetic acid in water. Chiralpak QD-AX and KSAACSP-001S enantioselective columns were used in the second dimension to separate LA and 3HB enantiomers, respectively. Mobile phases were mixed solutions of methanol and acetonitrile containing formic acid. The separation factors were 1.14 and 1.08, respectively. The detection limit of LA and 3HB enantiomers was 10 fmol/injection. This method was applied to human clinical samples; intra- and inter-day relative standard deviations of LA and 3HB enantiomers were, respectively, 1.04-3.25% and 1.61-5.12% in plasma, 9.19-11.2% and 4.60-5.89% in urine, and 7.12-8.90% and 2.86-6.97% in saliva. This novel analytical method is a powerful tool for investigating variations in LA and 3HB enantiomers under disease conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Identification and Characterization of a Novel Class of Extracellular Poly(3-Hydroxybutyrate) Depolymerase from Bacillus sp. Strain NRRL B-14911▿

    Science.gov (United States)

    Ma, Wan-Ting; Lin, Ju-Hui; Chen, Hui-Ju; Chen, Syuan-Yi; Shaw, Gwo-Chyuan

    2011-01-01

    The catalytic, linker, and denatured poly(3-hydroxybutyrate) (dPHB)-binding domains of bacterial extracellular PHB depolymerases (PhaZs) are classified into several different types. We now report a novel class of extracellular PHB depolymerase from Bacillus sp. strain NRRL B-14911. Its catalytic domain belongs to type 1, whereas its putative linker region neither possesses the sequence features of the three known types of linker domains nor exhibits significant amino acid sequence similarity to them. Instead, this putative linker region can be divided into two distinct linker domains of novel types: LD1 and LD2. LD1 shows significant amino acid sequence similarity to certain regions of a large group of PHB depolymerase-unrelated proteins. LD2 and its homologs are present in a small group of PhaZs. The remaining C-terminal portion of this PhaZ can be further divided into two distinct domains: SBD1 and SBD2. Each domain showed strong binding to dPHB, and there is no significant sequence similarity between them. Each domain neither possesses the sequence features of the two known types of dPHB-binding domains nor shows significant amino acid sequence similarity to them. These unique features indicate the presence of two novel and distinct types of dPHB-binding domains. Homologs of these novel domains also are present in the extracellular PhaZ of Bacillus megaterium and the putative extracellular PhaZs of Bacillus pseudofirmus and Bacillus sp. strain SG-1. The Bacillus sp. NRRL B-14911 PhaZ appears to be a representative of a novel class of extracellular PHB depolymerases. PMID:21948827

  9. Poly(3-hydroxybutyrate)/caffeic acid electrospun fibrous materials coated with polyelectrolyte complex and their antibacterial activity and in vitro antitumor effect against HeLa cells

    Energy Technology Data Exchange (ETDEWEB)

    Ignatova, Milena G. [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St, Bl. 103A, BG-1113 Sofia (Bulgaria); Manolova, Nevena E., E-mail: manolova@polymer.bas.bg [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St, Bl. 103A, BG-1113 Sofia (Bulgaria); Rashkov, Iliya B. [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St, Bl. 103A, BG-1113 Sofia (Bulgaria); Markova, Nadya D. [Institute of Microbiology, Bulgarian Academy of Sciences, Acad. G. Bonchev Bl. 26, BG-1113 Sofia (Bulgaria); Toshkova, Reneta A.; Georgieva, Ani K.; Nikolova, Elena B. [Institute of Experimental Morphology, Pathology and Anthropology with Museum, Bulgarian Academy of Sciences, Acad. G. Bonchev St, bl. 25, BG-1113 Sofia (Bulgaria)

    2016-08-01

    The purpose of this work was to investigate the possibility for the preparation of new poly(3-hydroxybutyrate) (PHB)/poly(ethylene glycol) (PEG)-based fibrous materials containing natural phenolic compound caffeic acid (CA) of diverse architectures, as well as to study the impact of the fiber composition on the in vitro CA release profile and on the biological properties of the fibrous materials. The application of the one-pot electrospinning enabled the fabrication of nanofibrous materials from PHB and PEG loaded with the CA. Materials with targeted design were obtained by coating with polyelectrolyte complex of alginate (Alg) and N,N,N-trimethylchitosan (TMCh). Three different processing paths were used to obtain coated mats: (i) with CA incorporated in the PHB/PEG core; (ii) with CA embedded in the Alg layer; and (iii) with CA included in the TMCh layer. The in vitro release of CA was modulated by controlling the composition and the architecture of the nanofibrous mats. The performed microbiological screening and MTT cell viability studies revealed that in contrast to the bare mats, the CA-containing nanofibrous materials were effective in suppressing the growth of the Gram-positive bacteria Staphylococcus aureus and the Gram-negative bacteria Escherichia coli and displayed good cytotoxicity against human cervical HeLa tumor cells. In addition, the proliferation of murine spleen lymphocytes and peritoneal macrophages was increased by the prepared CA-containing nanofibrous materials. The obtained materials are promising for antibacterial wound dressing applications as well as for application in local treatment of cervical tumors. - Highlights: • New caffeic acid-loaded materials from PHB and PEG were prepared by electrospinning. • Different design is achieved by coating and formation of polyelectrolyte complexes. • The control on the architecture of the mats enables modulating caffeic acid release. • The caffeic acid-loaded mats suppress the growth of

  10. Biocomposite scaffolds for bone regeneration: Role of chitosan and hydroxyapatite within poly-3-hydroxybutyrate-co-3-hydroxyvalerate on mechanical properties and in vitro evaluation.

    Science.gov (United States)

    Zhang, Sai; Prabhakaran, Molamma P; Qin, Xiaohong; Ramakrishna, Seeram

    2015-11-01

    Bio-engineered scaffolds for bone tissue regeneration is an exploding area of research mainly because they can satisfy the essential demands and current challenges in bone replacement therapies, by imitating the extracellular matrix (ECM) of the native bone. We fabricated bio-composite nanofibrous scaffolds with a blend of poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV), chitosan (CTS) and hydroxyapatite (HA) during this study. Morphological evaluation confirmed the fiber diameters of PHBV, PHBV/CTS (90:10), PHBV/CTS/HA4 (85.5:9.5:5) and PHBV/CTS/HA8 (81:9:10) as 405 ± 74 nm, 334 ± 82 nm, 316 ± 103 nm and 256 ± 110 nm, respectively. The PHBV/CTS/HA4 and PHBV/CTS/HA8 scaffolds were capable of enduring the long term culture of human fetal osteoblasts (hFOB) with ultimate tensile strength of 3.55 ± 0.22 MPa and 4.19 ± 0.19 MPa, respectively. The proliferation of osteoblasts on PHBV/CTS/HA8 scaffold was found 34.10% higher than that on PHBV scaffold on day 20. Cell maturation identified by alkaline phosphatase activity on day 20 was significantly higher on PHBV/CTS/HA8 scaffold than that on PHBV scaffold. The cells on PHBV/CTS/HA8 scaffold also acquired higher mineral deposition (25.79%) than the mineral deposition on PHBV scaffold by day 20, confirmed by EDX analysis. Based on the results, we concluded that the electrospun PHBV/CTS/HA8 scaffolds hold great potential to promote the regeneration of bone tissue due to the synergistic effect of chitosan and HA, whereby chitosan provided cell recognition sites while HA acted as a chelating agent for organizing the apatite-like mineralization. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. A fed-batch strategy to produce high poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxybutyrate) terpolymer yield with enhanced mechanical properties in bioreactor.

    Science.gov (United States)

    Aziz, Nursolehah Abd; Huong, Kai-Hee; Sipaut, Coswald Stephen; Amirul, A A

    2017-11-01

    This study reports an efficient fed-batch strategy to improve poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-4-hydroxybutyrate) [P(3HB-co-3HV-co-4HB)] terpolymer production by Cupriavidus sp. USMAA2-4 with enhanced mechanical properties in bioreactor. The cultivations have been performed by combining oleic acid with γ-butyrolactone at different concentration ratios with 1-pentanol at a fixed concentration. The batch and fed-batch fermentations have resulted in P(3HB-co-3HV-co-4HB) with compositions of 9-35 mol% 3HV and 4-24 mol% 4HB monomers. The DO-stat fed-batch fermentation strategies have significantly improved the production with a maximum 4.4-fold increment of cell dry weight (CDW). Besides, appropriate feeding of the substrates has resulted in an increment of terpolymer productivity from 0.086-0.347 g/L/h, with a significantly shortened cultivation time. The bacterial growth and terpolymer formation have been found to be affected by the concentration of carbon sources supplied. Characterization of P(3HB-co-3HV-co-4HB) has demonstrated that incorporation of 3HV and 4HB monomer has significantly improved the physical and thermodynamic properties of the polymers, by reducing the polymer's crystallinity. The tensile strength, Young's modulus of the terpolymer has been discovered to increase with the increase of M w . The fed-batch fermentation strategies employed in this study have resulted in terpolymers with a range of flexible materials having improved tensile strength and Young's modulus as compared to the terpolymer produced from batch fermentation. Possession of lower melting temperature indicates an enhanced thermal stability which broadens the polymer processing window.

  12. Control of glycerol production by rainbow smelt (Osmerus mordax) to provide freeze resistance and allow foraging at low winter temperatures.

    Science.gov (United States)

    Driedzic, William R; Ewart, K Vanya

    2004-11-01

    The rainbow smelt (Osmerus mordax) is a small anadromous fish that actively feeds under the ice at temperatures as low as the freeze point of seawater. Freezing is avoided through the production of both non-colligative antifreeze protein (AFP) and glycerol that acts in a colligative manner. Glycerol is constantly lost across the gills and skin, thus glycerol production must continue on a sustained basis at low winter temperatures. AFP begins to accumulate in early fall while water temperatures are still high. Glycerol production is triggered when water temperatures decrease to about 5 degrees C. Glycerol levels rapidly increase with carbon flow from dihydroxyacetone phosphate (DHAP) to glycerol 3-phosphate (G3P) to glycerol. Glucose/glycogen serves as the initial carbon source for glycerol accumulation with amino acids contributing thereafter. The period of glycerol accumulation is associated with increases in GPDH mRNA and PEPCK mRNA followed by elevations in protein synthesis and enzyme activities. Plasma glycerol levels may reach in excess of 500 mM in winter. The high freeze resistance allows rainbow smelt to invade water of low temperature and forage for food. The lower the temperature, the higher the glycerol must be, and the higher the glycerol the greater the loss to the environment through diffusion. During the winter, rainbow smelt feed upon protein rich invertebrates with glycerol production being fueled in part by dietary amino acids via the gluconeogenic pathway. At winter temperatures, glycerol is quantitatively more important than AFP in providing freeze resistance of blood; however, the importance of AFPs to other tissues is yet to be assessed. Glycerol levels rapidly plummet in the spring when water temperature is still close to 0 degrees C. During this period, freeze resistance must be provided by AFP alone. Overall, the phenomenon of glycerol production by rainbow smelt reveals an elegant connection of biochemistry to ecology that allows this

  13. Efficacy Study of Carrageenan as an Alternative Infused Material (Filler in Poly(3-hydroxybutyrate-co-3-hydroxyvalerate Porous 3D Scaffold

    Directory of Open Access Journals (Sweden)

    Nor Syamimi Che Johari

    2017-01-01

    Full Text Available Polymeric porous 3D scaffold plays an important role in culturing mammalian cells as ex vivo model. However, the scaffold used is ineffective due to its structural and cell acceptability weaknesses. Therefore, this research attempts to overcome the weaknesses by using carrageenan from red seaweed Kappaphycus alvarezii as an alternative infused material (filler of poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV porous 3D scaffold. The 3D scaffold was conventionally fabricated using the solvent-casting particulate-leaching (SCPL method. Carrageenan was later infused into 3D porous scaffolds under vacuum pressure and freeze-drying process. Five carrageenan concentrations were prepared and its physicochemical properties such as pH and viscosity were carried out on each concentration to determine the best solutions to produce a new composite 3D structure. The preliminary result shows that carrageenan concentrations of 2, 4, and 6% (w/v were considered the best solutions for the infusion process due to its stable rheology properties. The pH and viscosity profiles of three selected carrageenan solutions were exhibited in the range of 9.00–9.20 and 0.047–1.144 Pa·s, respectively. Moreover, the incorporated carrageenan gel fraction was in the range of 4.30% to 14.95% (w/w which was determined by gravimetric analysis and dye staining method (visual assessment. The well-infused carrageenan 3D scaffold was further characterized based on its internal morphology and degradability study. The vertical cross-sections of the scaffolds revealed homogeneous accumulation of dried gelatinous carrageenan which was covered throughout its pores wall. The degradation rate (K of the carrageenan infused 3D scaffold was between 0.01±1.66 (mg/day and 0.03±3.23 (mg/day. The higher the carrageenan concentration used, the faster the degradation rate occurring (p2 weeks. In conclusion, the usage of carrageenan as a composite material exhibits its great potential to be

  14. Glycerol carbonate as green solvent for pretreatment of sugarcane bagasse

    Science.gov (United States)

    2013-01-01

    Background Pretreatment of lignocellulosic biomass is a prerequisite for effective saccharification to produce fermentable sugars. In this study, “green” solvent systems based on acidified mixtures of glycerol carbonate (GC) and glycerol were used to treat sugarcane bagasse and the roles of each solvent in deconstructing biomass were determined. Results Pretreatment of sugarcane bagasse at 90°C for only 30 min with acidified GC produced a solid residue having a glucan digestibility of 90% and a glucose yield of 80%, which were significantly higher than a glucan digestibility of 16% and a glucose yield of 15% obtained for bagasse pretreated with acidified ethylene carbonate (EC). Biomass compositional analyses showed that GC pretreatment removed more lignin than EC pretreatment (84% vs 54%). Scanning electron microscopy (SEM) showed that fluffy and size-reduced fibres were produced from GC pretreatment whereas EC pretreatment produced compact particles of reduced size. The maximal glucan digestibility and glucose yield of GC/glycerol systems were about 7% lower than those of EC/ethylene glycol (EG) systems. Replacing up to 50 wt% of GC with glycerol did not negatively affect glucan digestibility and glucose yield. The results from pretreatment of microcrystalline cellulose (MCC) showed that (1) pretreatment with acidified alkylene glycol (AG) alone increased enzymatic digestibility compared to pretreatments with acidified alkylene carbonate (AC) alone and acidified mixtures of AC and AG, (2) pretreatment with acidified GC alone slightly increased, but with acidified EC alone significantly decreased, enzymatic digestibility compared to untreated MCC, and (3) there was a good positive linear correlation of enzymatic digestibility of treated and untreated MCC samples with congo red (CR) adsorption capacity. Conclusions Acidified GC alone was a more effective solvent for pretreatment of sugarcane bagasse than acidified EC alone. The higher glucose yield obtained

  15. A review of metabolism of labeled glucoses for use in measuring glucose recycling

    International Nuclear Information System (INIS)

    Russell, R.W.; Young, J.W.

    1990-01-01

    The fate of tritium from each carbon of D-glucose and the metabolism of L-glucose and 2-deoxy-D-glucose are known. Differences in metabolism of labeled glucoses can be used to quantify physical and chemical recycling of glucose. Only physical recycling is measured by [1- 3 H]-L-glucose, whereas [U- 14 C]-D-glucose measures total recycling. The difference between [1- 3 H]-L-glucose and [U- 14 C]-D-glucose, therefore, is chemical recycling. Recycling from extracellular binding sites and hepatic glucose 6-phosphate can be measured by difference between [1,2- 3 H]-2-deoxy-D-glucose and [1- 3 H]-L-glucose, and the difference in irreversible loss of the two will measure extrahepatic uptake of D-glucose. Recycling via Cori-alanine cycle plus CO 2 is the difference in irreversible loss measured by using [6- 3 H]-glucose and [U- 14 C]-D-glucose. Recycling via the hexose monophosphate pathway can be determined by difference in irreversible loss between [1- 3 H]-D-glucose and [6- 3 H]-D-glucose. Recycling via CO 2 and glycerol must be measured directly with [U- 14 C]glucose, bicarbonate, and glycerol. Recycling via hepatic glycogen can be estimated by subtracting all other measured chemical recycling from total chemical recycling. This review describes means to quantify glucose recycling in vivo, enabling studies of mechanisms for conservation and utilization of glucose. 54 references

  16. The effects of peroral glycerol on plasma osmolarity in diabetic patients and healthy individuals

    DEFF Research Database (Denmark)

    Thornit, Dorte Nellemann; Sander, Birgit; la Cour, Morten

    2009-01-01

    Glycerol is used as a peroral treatment of increased intraocular and intracranial pressure due to its osmotic effect despite the potential increase in blood pressure and blood glucose. We examined the effects of peroral glycerol in diabetic patients and healthy individuals on blood pressure......, capillary glucose, and plasma osmolarity. On two separate days, 15 diabetic patients ingested glycerol in doses of 855 and 1710 mg/kg body weight in a randomised, unmasked sequence. Five healthy individuals ingested a dose of 1710 mg/kg body weight. Mean arterial blood pressure (MAP), capillary glucose (CG......, non-significant increase occurred in blood pressure. Maximal DeltaCG was approximately 1 mM irrespective of the dose and presence of diabetes (p > 0.1). The pOSM response was analysed with a kinetic model and found independent of the presence of diabetes (p = 0.6). The maximal fitted DeltapOSM was 12...

  17. The Lubricity of Glycerol and its Solutions

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Jakobsen, J.

    2016-01-01

    the one predicted by hydrodynamic lubrication calculations. Addition of water to glycerol lowers the friction but increases the wear. In the present paper the lubricity (boundary lubrication performance) of glycerol and its solutions with water, ethanol and methanol is investigated. Dilution of glycerol...... up to 15% shows no wear in a standard wear test. Decrease in the glycerol content below 85% reveals significant wear and solutions with less than 15% glycerol show nearly the same wear as the solvent itself. The conclusion is that glycerol may be an excellent lubricant in hydrodynamics but when...

  18. Characterization of a Bio-Based, Biodegradable Class of Copolymers, Poly[(R)-3-Hydroxybutyrate-Co-(R)-3- Hydroxyhexanoate], and Application Development

    Science.gov (United States)

    Sobieski, Brian

    As modern society begins to focus on sustainability and renewable resources there is a growing need for the polymer industry to develop more environmentally friendly materials and practices. Part of this movement can be seen in the use of recycled materials in new products and in the development of bio-based, biodegradable polymers. Bio-based, biodegradable polymers are produced from renewable carbon sources, such as vegetable oils, typically polymerized using fermentation reactions via bacteria, and are able to be consumed by bacteria in landfills to completely convert the polymers to water and CO2. One class of such polymers are poly(hydroxyalkanoate)'s (PHAs), which are chiral, aliphatic polyesters. Within this class of polyesters are poly(hydroxybutyrate) (PHB) and the copolymer poly[(R)-3-hydroxybutyrate- co-(R)-3-hydroxyhexanoate] (PHBHx), which have received extensive study due to their material properties as thermoplastics. Although the properties of PHB have been widely explored, much still remains to be understood about these promising biodegradable polymers. Specifically, PHB and its copolymers exhibit physical gelation in most solvents, yet the origin and mechanism of gelation and the properties of the resulting gel state are unknown. This research effort was primarily focused on investigating the physical gel state of PHBHx. Five goals were laid out and completed: determining the origin of gelation, the mechanism of gelation, the structure of the gel state, the properties of the gel state, and the effects of gelation on electrospun fibers of PHBHx. These goals were achieved through material characterization of the gel state utilizing infrared spectroscopy/two-dimensional correlation spectroscopy, differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, and many other analysis methods. Crystallization of the polymer in solution was found to cause gelation in PHBHx solutions, where the polymer crystals act as tie points forming

  19. Palatability, digestibility, and metabolizable energy of dietary glycerol in adult cats.

    Science.gov (United States)

    Machado, G S; Pezzali, J G; Marx, F R; Kessler, A M; Trevizan, L

    2017-02-01

    Glycerol is a humectant, which reduces water activity when added to the diet. This property seems to offer dietary benefits, specifically in high-moisture diets for cats, where some humectants cannot be used. According to the U.S. Food and Drug Administration, glycerol is generally recognized as sustenance safe (GRAS). It is suggested that cats are able to metabolize glycerol and use it as an energy source without compromising health. Three experiments were conducted to evaluate the following characteristics of glycerol in the diet for cats: 1) a preference test, 2) digestibility, ME, and fecal and urinary characteristics, and 3) postprandial plasma glycemia. Twelve healthy adult female cats were randomly distributed among 4 treatments consisting of a basal diet (4,090 kcal ME/kg DM, 32% CP, 11% fat, 2.3% crude fiber, and 7.0% ash) and 3 diets with varying percentages of glycerol, made by replacing the basal diet with 2.5, 5.0, and 10.0% purified glycerol (99.5%). The inclusion of glycerol proportionally reduced ( Cats did not show a preference for any diet in particular ( > 0.05). The digestibility assays showed that increasing dietary glycerol levels did not affect food intake or the apparent total tract digestibility of macronutrients and energy ( > 0.05). The inclusion of glycerol in the diets did not alter the stool moisture, fecal score, or urine volume. However, glycerol was detected in urine when it was incorporated into the diet at 10%. Glycemia increased up to 900 min following the first meal after the fasting period with no difference between treatments, even when the means were adjusted for food intake. The blood glucose area under the curve also showed no significant difference between treatments ( > 0.05). Cats accepted glycerol under the conditions of the study, and its nutritional value was determined as it has been done for other species. The ME of glycerol for adult cats was estimated to be 3,185 kcal/kg DM. Supplementing the diets of the cats

  20. Preparation of silver powder through glycerol process

    Indian Academy of Sciences (India)

    High purity fine silver powder with uniform particle morphology was prepared through glycerol process. The process involves reduction of silver nitrate by glycerol under atmospheric conditions at a temperature below 175°C. Glycerol, in this process, acts as a solvent as well as a reducing agent. The powders prepared ...

  1. Preparation of silver powder through glycerol process

    Indian Academy of Sciences (India)

    Unknown

    Abstract. High purity fine silver powder with uniform particle morphology was prepared through glycerol process. The process involves reduction of silver nitrate by glycerol under atmospheric conditions at a tem- perature below 175°C. Glycerol, in this process, acts as a solvent as well as a reducing agent. The powders.

  2. Metabolic effects of glycerol supplementation and aerobic physical training on Wistar rats.

    Science.gov (United States)

    Andrade, Eric Francelino; Lobato, Raquel Vieira; Araújo, Ticiana Vasques; Orlando, Débora Ribeiro; Gomes, Núbia Ferreira; Alvarenga, Renata Ribeiro; Rogatto, Gustavo Puggina; Zangeronimo, Márcio Gilberto; Pereira, Luciano José

    2014-09-01

    We evaluated the effects of oral glycerol supplementation on trained rats fed a normal diet. Wistar rats were distributed among 6 groups in a completely randomized 2 × 3 factorial design. The animals were subjected to 6 weeks of aerobic training. In the last 4 weeks, the animals' diet was supplemented with saline, glucose, or glycerol. Data were subjected to one-way analysis of variance (ANOVA) followed by a Student-Newmann-Keuls test, with values for P < 0.05 considered statistically significant. The change in body mass was lower in the trained groups, and their food and water consumption were higher. Glycerol supplementation resulted in an increase in the levels of triacylglycerol (TAG) and total cholesterol, as well as in the area and diameter of adipocytes. When associated with training, these parameters were similar to those of other trained groups. Levels of low-density lipoprotein + very-low-density lipoprotein cholesterol decreased in the trained animals that received glycerol compared with the non-trained ones. Glycerol consumption caused a reduction in food intake and increased the villous:crypt (V:C) ratio. No changes in glycemia, high density lipoproteins, or density of adipocytes were observed. Supplementation with glycerol together with aerobic physical training promoted beneficial metabolic effects. However, in non-trained rats glycerol increased the diameter and area of adipocytes, as well as the levels of TAG and total cholesterol.

  3. Síntese e caracterização do copolímero poli(3-hidroxibutirato-co-ε-caprolactona a partir de poli (3-hidroxibutirato e poli(ε-caprolactona Synthesis and characterization of the copolymer poly(3-poly(3-hydroxybutyrate-co-ε-caprolactone from poly(3-hydroxybutyrate and poly(ε-caprolactone

    Directory of Open Access Journals (Sweden)

    Juan P. B. Roa

    2010-09-01

    Full Text Available O copolímero poli(3-hidroxibutirato-co-ε-caprolactona foi sintetizado por transesterificação, a partir dos homopolímeros PHB e PCL, usando acetilacetonato de zircônio(IV, como catalisador, nas concentrações de 20, 50 e 80% de PHB em massa. Os copolímeros foram caracterizados por GPC, métodos espectroscópicos (RMN-¹H, RMN-13C e IV-FT e métodos térmicos (TG e DSC. A rota de síntese utilizada mostrou-se eficaz na síntese dos copolímeros P(HB-co-CL, os quais mostraram diminuição das cadeias poliméricas, apresentando Mw inferior a 24.000Daltons. Todos os copolímeros obtidos são termicamente mais estáveis que o PHB e com menor cristalinidade que os homopolímeros de partida. Esses materiais são bons candidatos para utilização como biomateriais em matrizes para liberação controlada de fármacos ou mesmo como compatibilizante em blendas PHB/PCL.In the present work, the copolymer poly(3-hydroxybutyrate-co-ε-caprolactone, P(HB-co-CL, was prepared by transesterification reaction from PHB and PCL. Zirconium (IV acetylacetonate was used as catalyst and the copolymers were obtained in a wide range of compositions of PHB/PCL (20/80, 50/50, 80/20. These copolymers were characterized by GPC, FT-IR, ¹H-NMR, 13C-NMR, TG, and DSC. The copolymers had weight average molecular weight less than 24.000 Daltons. All the systems were thermally more stable than PHB, showing lower crystallinity than the homopolymers. These materials are good candidates to be used as biomaterials, in drug release matrices, or even as PHB/PCL blends compatibilizers.

  4. Uncovering transcriptional regulation of glycerol metabolism in Aspergilli through genome-wide gene expression data anlysis

    DEFF Research Database (Denmark)

    Salazar, Margarita Pena; Vongsangnak, Wanwipa; Panagiotou, Gianni

    2009-01-01

    Glycerol is catabolized by a wide range of microorganisms including Aspergillus species. To identify the transcriptional regulation of glycerol metabolism in Aspergillus, we analyzed data from triplicate batch fermentations of three different Aspergilli (Aspergillus nidulans, Aspergillus oryzae...... and Aspergillus niger) with glucose and glycerol as carbon sources. Protein comparisons and cross-analysis with gene expression data of all three species resulted in the identification of 88 genes having a conserved response across the three Aspergilli. A promoter analysis of the up-regulated genes led....... niger. Our transcriptome analysis indicated that genes involved in ethanol, glycerol, fatty acid, amino acids and formate utilization are putatively regulated by Adr1 in Aspergilli as in Saccharomyces cerevisiae and this transcription factor therefore is likely to be cross-species conserved among...

  5. Processing and characterization of biocomposites Poly (3-hydroxybutyrate) / hydroxyapatite for temporary support in bone regeneration; Processamento e caracterizacao de biocompositos Poli (3-hidroxibutirato) / hidroxiapatita para suporte temporario na regeneracao ossea

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Cyntia Esteves; Ferreira, Willian Hermogenes; Andrade, Cristina Tristao [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Centro de Tecnologia. Instituto de Macromoleculas Professora Eloisa Mano

    2011-07-01

    Composite materials like biopolymer / hydroxyapatite (HA) has been attracting the interest of researchers because of its applications in medicine. These materials have been used as temporary supports during the regeneration of bone tissue. In this work, poly (3-hydroxybutyrate) (PHB) was chosen as matrix because it has good processability and biocompatibility. The HA was obtained by precipitation from calcium hydroxide and phosphoric acid, varying the speed of dripping, the synthesis temperature and time of calcination. The techniques of infrared absorption spectroscopy and X-ray diffraction (XRD) were used to characterize the samples synthesized HA. The biocomposites were prepared in an internal mixer, with compositions PHB / HA varied. After processing, the biocomposites were ground, characterized by XRD analysis and the crystallinity index. The aim of this study was to examine the variables during the synthesis of HA and its thermal treatment in order to obtain a powder of HA using a simple technique and accessible, creating good properties for the biocomposites prepared. (author)

  6. Synthesis, Characterization and Biocompatibility of Biodegradable Elastomeric Poly(ether-ester urethane)s Based on Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) and Poly(ethylene glycol) via Melting Polymerization

    DEFF Research Database (Denmark)

    Li, Zibiao; Yang, Xiaodi; Wu, Linping

    2009-01-01

    contact angle measurements revealed that surface hydrophilicity of the PUs was enhanced by incorporating the PEG segment into PHBHHx polymer backbone. The mechanical properties assessment of the PUs recorded an improved and adjustable ductility and toughness than pure PHBHHx while preserving the tensile......Poly(ether-ester urethane)s (PUs) multiblock co-polymers were synthesized from telechelic hydroxylated poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) and poly(ethylene glycol) (PEG) via a melting polymerization (MP) process using 1,6-hexamethylene diisocyanate (HDI) as a non-toxic coupling...... transform infrared spectroscopy (FT-IR). The PU produced via the MP method showed a higher molecular weight than those resulting from the solvent polymerization (SP) reported previously. Thermal properties showed enhanced thermal stability with semi-crystalline morphology via incorporation of PEG...

  7. Effect of Organo-Modified Nanoclay on the Thermal and Bulk Structural Properties of Poly(3-hydroxybutyrate-Epoxidized Natural Rubber Blends: Formation of Multi-Components Biobased Nanohybrids

    Directory of Open Access Journals (Sweden)

    Ali Salehabadi

    2014-06-01

    Full Text Available Multi-component nanohybrids comprising of organo-modified montmorillonite (MMT and immiscible biopolymer blends of poly(3-hydroxybutyrate (PHB and epoxidized natural rubber (ENR-50 were prepared by solvent casting technique. The one and three dimensional morphology of PHB/ENR-50/MMT systems were studied using Polarizing Optical Microscopy (POM and Scanning Electron Microscopy (SEM. Differential scanning calorimetry (DSC technique was used to evaluate the thermal properties of the nanohybrids. The melting temperature (Tm and enthalpy of melting (ΔHm of PHB decrease with respect to the increase in ENR-50 as well as MMT content. The non-isothermal decomposition of the nanohybrids was studied using thermogravimetric (TG-DTG analysis. FTIR-ATR spectra supported ring opening of the epoxide group via reaction with carboxyl group of PHB and amines of organic modifier. The reaction mechanism towards the formation of the nanohybrids is proposed.

  8. The expression of glycerol facilitators from various yeast species improves growth on glycerol of Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Klein, Mathias; Islam, Zia ul; Knudsen, Peter Boldsen

    2016-01-01

    Glycerol is an abundant by-product during biodiesel production and additionally has several assets compared to sugars when used as a carbon source for growing microorganisms in the context of biotechnological applications. However, most strains of the platform production organism Saccharomyces...... cerevisiae grow poorly in synthetic glycerol medium. It has been hypothesized that the uptake of glycerol could be a major bottleneck for the utilization of glycerol in S. cerevisiae. This species exclusively relies on an active transport system for glycerol uptake. This work demonstrates that the expression...... of predicted glycerol facilitators (Fps1 homologues) from superior glycerol-utilizing yeast species such as Pachysolen tannophilus, Komagataella pastoris, Yarrowia lipolytica and Cyberlindnera jadinii significantly improves the growth performance on glycerol of the previously selected glycerol-consuming S...

  9. The absorption and distribution of 1- 14 C-glycerol and D-5 3 H ...

    African Journals Online (AJOL)

    The absorption and distribution of 1-14C-glycerol and D-53H-glucose from the reproductive tracts of female mice. W.J. Neville. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO USE AJOL.

  10. Hyperhydrating with glycerol: implications for athletic performance.

    Science.gov (United States)

    Wagner, D R

    1999-02-01

    Small decreases in hydration status can result in a dramatic decrement in athletic performance and greatly increase the risk of thermal injury. Because of its osmotic properties, which enable greater fluid retention than the ingestion of water alone, glycerol has been proposed as a hyperhydrating agent. In fact, glycerol is now commercially available and marketed as a sport supplement to be ingested with water or sport drinks; thus, dietitians need to be cognizant of this new addition to the sports nutrition table. The results of glycerol-induced hyperhydration research have been equivocal, most likely because of methodologic differences between studies, such as variations in the intensity of exercise, environmental conditions, and concentration or dose of glycerol administered. Although the suggested dosage of glycerol depends on body size and varies between manufacturers, 1 g/kg body weight with an additional 1.5 L fluid taken 60 to 120 minutes before competition is standard. Some test subjects reported feeling bloated or nauseated after ingesting glycerol. This review examines glycerol-induced hyperhydration research and the safety of ingesting glycerol, discusses commercial availability of glycerol, and makes recommendations for glycerol-induced hyperhydration research.

  11. Glycerol as a carbon source for xantan production by Xanthomonas campestris isolates

    Directory of Open Access Journals (Sweden)

    Bajić Bojana Ž.

    2015-01-01

    Full Text Available The success of xanthan biosynthesis depends on several factors, most importantly the genetic potential of the production microorganism and cultivation media composition. Cultivation media composition affects the yield and quality of the desired product as well as production costs. This is why many studies focus on finding cheap alternative raw materials, especially carbon sources, to replace commercially used glucose and sucrose. In addition to the Xanthomonas campestris ATCC 13951 which is the primary industrial production microorganism, other Xanthomonas strains can produce xanthan as well. Under the same conditions, different strains produce different amounts of the biopolymer of varying quality. The aim of this paper is to compare producibility of phytopathogenic X. campestris strains, isolated from the environment with the reference X. campestris ATCC 13951 strain and to estimate the possibility of xanthan production using alternative glycerol-based media than the synthetic glucose-based media. Submerged cultivation on the medium based on glucose or glycerol (2.0 %w/v was performed using the reference strain and eight isolated X. campestris strains. In order to assess the success of biosynthesis, xanthan yield and rheological properties were determined. Strains isolated from the environment produced yields between 2.98 g/L and 12.17 g/L on the glucose-based medium and 1.68 g/L and 6.31 g/L on the glycerol-based medium. Additionally, X. campestris ATCC 13951 provided the highest yield when using glucose (13.24 g/L, as well as glycerol-based medium (7.44 g/L. The obtained results indicate that in the applied experimental conditions and using all tested strains, glycerol is viable as a carbon source for the production of xanthan.

  12. Anaerobic pathways of glycerol dissimilation by Enterobacter agglomerans CNCM 1210: limitations and regulations.

    Science.gov (United States)

    Barbirato, F; Astruc, S; Soucaille, P; Camarasa, C; Salmon, J M; Bories, A

    1997-07-01

    Continuous cultures of Enterobacter agglomerans CNCM 1210 were performed under regulated pH conditions (pH 7.0) with glycerol or glucose (20 g l-1) as carbon source. Cultures grown on glucose produced mainly acetate, ethanol and formate. In contrast, 1,3-propanediol (PPD) was the main product with glycerol. The carbon flow distribution at branching metabolic points was investigated. Higher PPD yields with increased dilution rate were correlated with an important increase in the relative ratio of glycerol dehydratase to glycerol dehydrogenase. Determination of intracellular triose-phosphate and fructose 1,6-biphosphate concentrations demonstrated that glyceraldehyde-3-phosphate dehydrogenase is the limiting step in glycerol dissimilation. At the pyruvate branching point, pyruvate dehydrogenase (PDH) activity was systematically detected. The pyruvate flow shifted to PDH is suspected to represent up to 22% of the acetyl-CoA formed. In addition, this enzyme pattern combined with the enhanced in vivo lactate dehydrogenase activity at high growth rates, was correlated with a decrease in the pyruvate formate-lyase activity. A regulation of this latter enzyme by the accumulation of triose-phosphate is suspected.

  13. Seasonal variability of branched glycerol dialkyl glycerol tetraethers (brGDGTs) in a temperate lake system

    NARCIS (Netherlands)

    Loomis, S.E.; Russell, J.M.; Heureux, A.M.; D'Andrea, W.J.; Sinninghe Damsté, J.S.

    2014-01-01

    Quantitative climate reconstructions are crucial for understanding the magnitude of and mechanisms behind natural and anthropogenic climate change, yet there are few proxies that can reliably reconstruct terrestrial temperature. Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial

  14. Efficient green methanol synthesis from glycerol

    OpenAIRE

    Haider, Muhammad H.; Dummer, Nicholas F.; Knight, David W.; Jenkins, Robert L.; Howard, Mark; Moulijn, Jacob; Taylor, Stuart H.; Hutchings, Graham J.

    2015-01-01

    The production of biodiesel from the transesterification of plant-derived triglycerides with methanol has been commercialized extensively. Impure glycerol is obtained as a by-product at roughly one-tenth the mass of the biodiesel. Utilization of this crude glycerol is important in improving the viability of the overall process. Here we show that crude glycerol can be reacted with water over very simple basic or redox oxide catalysts to produce methanol in high yields, together with other usef...

  15. Inhibition of cell proliferation by glycerol

    International Nuclear Information System (INIS)

    Wiebe, J.P.; Dinsdale, C.J.

    1991-01-01

    The effect of glycerol on proliferation of BHK, CHO, HBL, MCF-7, and human glioma cells was studied. Cell proliferation was significantly decreased in all the cell lines at glycerol concentrations of 2-4% in the culture medium. The inhibition was dose-dependent, complete suppression of proliferation occurring at a glycerol concentration of 4% for the MCF-7 cell line and 6-8% for the BHK, CHO and human glioma cells. Studies on [ 3 H]thymidine incorporation correlate with the effect on cell proliferation. The viability of the cells was not significantly affected until higher concentrations of glycerol were present. Recovery studies with BHK cells indicated that replacement of the glycerol medium with glycerol-free medium resulted in full recovery following exposure to 4% glycerol and only partial recovery of proliferation rate following exposure to 10-12% glycerol. It is concluded that glycerol, a substance that is normally present in tissues, can serve as a potent inhibitor of cell proliferation

  16. Subcloning, expression, purification, and characterization of Haemophilus influenzae glycerol kinase.

    Science.gov (United States)

    Pawlyk, A C; Pettigrew, D W

    2001-06-01

    Glycerol kinase (EC 2.7.1.30) is a bacterial sugar kinase and a member of the sugar kinase/actin/hsc-70 superfamily of enzymes. The enzyme from Escherichia coli is an allosteric regulatory enzyme whose activity is inhibited by fructose 1,6-bisphosphate (FBP) and the glucose-specific phosphocarrier of the phosphoenolpyruvate:glycose phosphotransferase system, IIA(Glc) (previously termed III(Glc)). Comparison of its primary structure with that of the highly similar Haemophilus influenzae glycerol kinase reveals that the amino acid sequence for the binding site for FBP is conserved while the amino acid sequence for the binding site for IIA(Glc) contains differences that are predicted to prevent its inhibition. To test this hypothesis, the H. influenzae glpK gene was assembled from DNA library fragments and subcloned into pUC18. The enzyme is expressed at high levels in E. coli. It was purified to greater than 90% homogeneity by taking advantage of its solubility behavior in a procedure that requires no column chromatography. The initial-velocity kinetic parameters of the purified enzyme are similar to those of the E. coli glycerol kinase. The H. influenzae glycerol kinase is inhibited by FBP but not by IIA(Glc), in agreement with the prediction based on sequence comparison. Sedimentation velocity experiments reveal that inhibition of HiGK by FBP is associated with oligomerization, behavior which is similar to EcGK. The possibility of utilizing mutagenesis studies to exploit the high degree of similarity of these two enzymes to elucidate the mechanism of allosteric regulation by IIA(Glc) is discussed. Copyright 2001 Academic Press.

  17. Lipolytic response to glucose infusion in human subjects

    International Nuclear Information System (INIS)

    Wolfe, R.R.; Peters, E.J.

    1987-01-01

    The authors have determined the effect of various rates of glucose infusion on the rates of release of glycerol (R/sub a/ glycerol), free fatty acids (R/sub a/ FFA), and on energy metabolism in normal human volunteers. Plasma kinetics were determined with use of the stable isotopic tracers D-5-glycerol and [1- 13 C]palmitate, and energy metabolism was determined by indirect calorimetry. The effect of glucose infusion on R/sub a/ glycerol and R/sub a/ FFA was dose-dependent. At 4 mg x kg -1 x min -1 , both R/sub a/ glycerol and R/sub a/ FFA were suppressed; at 8 mg x kg -1 x min -1 , R/sub a/ FFA was even more depressed, but R/sub a/ glycerol was similar to the value during the 4 mg x kg -1 x min -1 infusion. At all infusion rates tested, the amount of potential energy available from the sum of the glucose infusion and endogenously mobilized fat was always greater than when no glucose was infused. Glucose decreased fat mobilization by both inhibiting lipolysis and stimulating reesterification, thus causing a significant increase in triglyceride-fatty acid substrate cycling within the adipose tissue. Plasma insulin was determined by radioimmunoassay

  18. Production of dihydroxyacetone from glycerol by engineered ...

    African Journals Online (AJOL)

    ... the whole-cell biotransformation process. These results should be useful for the development of advanced bioprocess in terms of glycerol utilization. Keywords: Dihydroxyacetone, Glycerol dehydrogenase, NAD+, whole-cell biotransformation, Escherichia coli. African Journal of Biotechnology Vol. 12(27), pp. 4387-4392 ...

  19. Production of dihydroxyacetone from glycerol by engineered ...

    African Journals Online (AJOL)

    zino

    2013-07-03

    Jul 3, 2013 ... (Accession No. CP000948) in E. coli, catalyzes reversible reactions for the interconversion of glycerol and DHA. In the forward reaction, glycerol is oxidized to DHA at the expense of a stoichiometric amount of the cofactor NAD+. Therefore, NAD+ supply and recycling is essential to drive the forward reaction ...

  20. Biosynthesis of glycerol carbonate from glycerol by lipase in dimethyl carbonate as the solvent.

    Science.gov (United States)

    Lee, Kyung Hwa; Park, Chang-Ho; Lee, Eun Yeol

    2010-11-01

    Glycerol carbonate was synthesized from renewable glycerol and dimethyl carbonate using lipase in solvent-free reaction system in which excess dimethyl carbonate played as the reaction medium. A variety of lipases have been tested for their abilities to catalyze transesterification reaction, and Candida antartica lipase B and Novozyme 435 exhibited higher catalytic activities. The silica-coated glycerol with a 1:1 ratio was supplied to prevent two-phase formation between hydrophobic dimethyl carbonate and hydrophilic glycerol. Glycerol carbonate was successfully synthesized with more than 90% conversion from dimethyl carbonate and glycerol with a molar ratio of 10 using Novozyme 435-catalyzed transesterification at 70 °C. The Novozyme 435 [5% (w/w) and 20% (w/w)] and silica gel were more than four times recycled with good stability in a repeated batch operation for the solvent-free synthesis of glycerol carbonate.

  1. Enhanced glucose cycling and suppressed de novo synthesis of glucose-6-phosphate result in a net unchanged hepatic glucose output in ob/ob mice

    NARCIS (Netherlands)

    Bandsma, RHJ; Grefhorst, A; van Dijk, TH; van der Sluijs, FH; Hammer, A; Reijngoud, DJ; Kuipers, F

    2004-01-01

    Aims/hypothesis. Leptin-deficient ob/ob mice are hyperinsulinaemic and hyperglycaemic; however, the cause of hyperglycaemia remains largely unknown. Methods. Glucose metabolism in vivo in 9-h fasted ob/ob mice and lean littermates was studied by infusing [U-C-13]-glucose, [2-C-13]-glycerol,

  2. Green Nanotechnology for Synthesis and characterization of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) nanoparticles for sustained bortezomib release using supercritical CO2 assisted particle formation combined with electrodeposition.

    Science.gov (United States)

    Demirdöğen, Ruken Esra; Emen, Fatih Mehmet; Ocakoglu, Kasim; Murugan, Paramasivam; Sudesh, Kumar; Avşar, Göktürk

    2018-02-01

    Carbon dioxide assisted particle formation combined with electrospraying using supercritical CO 2 (scCO 2 ) as an aid (Carbon Dioxide Assisted Nebulization-Electrodeposition, CAN-ED) was used to produce Bortezomib loaded poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) P(3HB-co-3HHx) nanoparticles for sustained release. The morphology and structure of the prepared nanoparticles were investigated by SEM, TEM and FT-IR spectroscopy. Average diameter of particles obtained was 155nm and the average core sizes of P(3HB-co-3HHx) nanoparticles were between 6 and 13nm. The drug loading capacity, drug release and stability of Bortezomib loaded P(3HB-co-3HHx) nanoparticles were analyzed. The maximum loading capacity was achieved at pH=6.0 in phosphate buffer (K 2 HPO 4 /KH 2 PO 4 ). It was found that temperature did not affect the stability of Bortezomib loaded nanoparticles and it was good both at 37°C and 4°C. This study pointed out that CAN-ED is a green method to produce P(3HB-co-3HHx) nanoparticles for pH responsive targeting of Bortezomib especially to parts of the body where size exclusion is not crucial. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Dexamethasone-loaded poly(3-hydroxybutyrate-co-3-hydroxyvalerate) microparticles for controlled release;Microparticulas de poli(3-hidroxibutirato-co-3-hidroxivalerato) para a liberacao modificada da dexametasona

    Energy Technology Data Exchange (ETDEWEB)

    Riekes, Manoela Klueppel; Paula, Josiane Padilha de; Farago, Paulo Vitor, E-mail: pvfarago@uepg.b [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil); Zawadzki, Sonia Faria [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Quimica

    2009-07-01

    Dexamethasone (DEX) has been widely used for the treatment of ulcerative colitis. The aim of the present study was to obtain DEX-loaded poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV) microparticles prepared by simple emulsion/solvent evaporation method. The drug loading and the encapsulation efficiency were determined by a previously validated UV method at 233 nm. Morphological, spectroscopical and dissolution analyses were also performed. The microparticles (formulation F no. 0, F no. 1 and F no. 2) were successfully obtained as off-white powders. A drug loading of 92.27 mg.g {sup -1} and 218.54 mg.g{sup -1} and an encapsulation efficiency of 93.96 % and 87.43 % were respectively observed for F no. 1 and F no. 2. Particles showed spherical and rough aspect by SEM. X-ray diffraction analysis demonstrated that the encapsulation reduced the drug crystallinity. FTIR spectra showed that no chemical bonding occurred between PHBV and DEX. Drug-loaded microparticles revealed controlled release profiles compared to pure DEX. (author)

  4. Ecotoxicology of Glycerol Monolaurate nanocapsules.

    Science.gov (United States)

    Lopes, Leonardo Q S; Santos, Cayane G; de Almeida Vaucher, Rodrigo; Raffin, Renata P; da Silva, Aleksandro S; Baretta, Dilmar; Maccari, Ana Paula; Giombelli, Laura Caroline D D; Volpato, Andreia; Arruda, Jessyka; de Ávila Scheeren, Cecília; Baldisserotto, Bernardo; Santos, Roberto C V

    2017-05-01

    Glycerol Monolaurate (GML) is a compound with known antimicrobial potential, however it is not much used due to its low solubility in water and high melting point. The nanoencapsulation of some drugs offers several advantages such as improved stability and solubility in water. The present study aimed to produce, characterize, and evaluate the ecotoxicity of GML nanocapsules. The nanocapsules were produced and presented a mean diameter of 210nm, polydispersity index of 0.044, and zeta potential of -23.4mV. The electron microscopy images showed the nanometric size and spherical shape. The assay in soil showed that GML has a high toxicity while the GML nanocapsules showed decreased toxic effects. Nanostructuration also protected the Rhamdia quelen against the toxic effects of GML. Concluding, the formulation shows positive results and is useful to predict the success of development besides not damaging the soil. Copyright © 2017. Published by Elsevier Inc.

  5. Improved 1,3-Propanediol Synthesis from Glycerol by the Robust Lactobacillus reuteri Strain DSM 20016.

    Science.gov (United States)

    Ricci, Maria Antonietta; Russo, Annamaria; Pisano, Isabella; Palmieri, Luigi; de Angelis, Maria; Agrimi, Gennaro

    2015-06-01

    Various Lactobacillus reuteri strains were screened for the ability to convert glycerol to 1,3- propanediol (1,3-PDO) in a glycerol-glucose co-fermentation. Only L. reuteri DSM 20016, a well-known probiotic, was able to efficiently carry out this bioconversion. Several process strategies were employed to improve this process. CO(2+) addition to the fermentation medium, led to a high product titer (46 g/l) of 1,3-PDO and to improved biomass synthesis. L. reuteri DSM 20016 produced also ca. 3 μg/g of cell dry weight of vitamin B12, conferring an economic value to the biomass produced in the process. Incidentally, we found that L. reuteri displays the highest resistance to CO(2+) ions ever reported for a microorganism. Two waste materials (crude glycerol from biodiesel industry and spruce hydrolysate from paper industry) alone or in combination were used as feedstocks for the production of 1,3-PDO by L. reuteri DSM 20016. Crude glycerol was efficiently converted into 1,3-PDO although with a lower titer than pure glycerol (-18%). Compared with the fermentation carried out with pure substrates, the 1,3- PDO produced was significantly lower (40.7 vs. 24.2 g/l) using cellulosic hydrolysate and crude glycerol, but strong increases of the maximal biomass produced (+27%) and of the glucose consumption rate (+46%) were found. The results of this study lay the foundation for further investigations to exploit the biotechnological potential of L. reuteri DSM 20016 to produce 1,3-PDO and vitamin B12 using industry byproducts.

  6. Esters of oligo-(glycerol carbonate-glycerol): New biobased oligomeric surfactants.

    Science.gov (United States)

    Holmiere, Sébastien; Valentin, Romain; Maréchal, Philippe; Mouloungui, Zéphirin

    2017-02-01

    Glycerol carbonate is one of the most potentially multifunction glycerol-derived compounds. Glycerol is an important by-product of the oleochemical industry. The oligomerization of glycerol carbonate, assisted by the glycerol, results in the production of polyhydroxylated oligomers rich in linear carbonate groups. The polar moieties of these oligomers (M w ethylene oxide as in most commercial surfactants. The insertion of linear carbonate groups into the glycerol-based skeleton rendered the oligomers amphiphilic, resulting in a decrease in air/water surface tension to 57mN/m. We improved the physical and chemical properties of the oligomers, by altering the type of acylation reaction and the nature of the acyl donor. The polar head is constituted of homo-oligomers and hetero-oligomers. Homo-oligomers are oligoglycerol and/or oligocarbonate, hetero-oligomers are oligo(glycerol-glycerol carbonate). Coprah oligoesters had the best surfactant properties (CMCethylene glycol monododecyl ether, glycol ethers and fatty acid esters of sorbitan polyethoxylates. The self-assembling properties of oligocarbonate esters were highlighted by their ability to stabilize inverse and multiple emulsions. The oligo-(glycerol carbonate-glycerol ether) with relatively low molecular weights showed properties of relatively high-molecular weight molecules, and constitute a viable "green" alternative to ethoxylated surfactants. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Effects of feeding dry glycerol on milk production, nutrients digestibility and blood components in primiparous Holstein dairy cows during the early postpartum period

    Energy Technology Data Exchange (ETDEWEB)

    Kafilzadeh, F.; Piri, V.; Karami-Shabankareh, H.

    2015-07-01

    The aim of this study was to evaluate the glucogenic property of glycerol supplementation in the dairy cow’s diet. Sixty primiparous cows (control, n=30, and glycerol supplemented, n=30) were used to measure milk yield and components, blood hormone and metabolite profiles, and body condition score. Feed intake and apparent total-tract digestibility were also measured using 10 primiparous cows (control, n=5, and glycerol supplemented, n=5). Dry glycerol was top dressed at 250 g/day/cow from parturition to 21 days postpartum. Average feed intake, milk yield and components were not affected by glycerol supplementation. Apparent total–tract digestibility of organic matter and neutral detergent fibre were not influenced by dry glycerol supplementation, but lipid digestibility was greater (p=0.01) in cows fed glycerol. The serum concentration of glucose and insulin tended to be higher in dry glycerol-supplemented cows (p=0.1; p=0.06, respectively). While, serum concentrations of nonesterified fatty acids and β-hydroxybutyrate were not affected. Supplemented cows had lower body condition loss during weeks 1 to 5 after calving (p=0.09). The glucogenic effect of glycerol did not affect milk yield during the first 3 weeks of lactation. However, daily milk yield during the 13 weeks recording period was higher in the glycerol-supplemented cows (28.5 vs. 30.3 kg, p<0.001). Percentages of cows cycling at the planned breeding date was greater (p=0.01) for cows fed dry glycerol. The results demonstrated that feeding dry glycerol as a glucogenic supply could be useful in saving body reserves and improving energy balance of primiparous Holstein dairy cows during the early postpartum period. (Author)

  8. Effect of crude glycerol from South African biodiesel production on ...

    African Journals Online (AJOL)

    A study was carried out to evaluate the effects of dietary inclusion of crude glycerol as a partial replacement of maize at 50 g/kg and 100 g/kg in pig grower diets. Three experimental diets were formulated, a control (CN) and two diets containing 50 g/kg (low glycerol (LG)) and 100 g/kg (high glycerol (HG)) glycerol.

  9. Valorization of crude glycerol from biodiesel production

    Directory of Open Access Journals (Sweden)

    Konstantinović Sandra S.

    2016-01-01

    Full Text Available The increased production of biodiesel as an alternative fuel involves the simultaneous growth in production of crude glycerol as its main by-product. Therefore, the feasibility and sustainability of biodiesel production requires the effective utilization of crude glycerol. This review describes various uses of crude glycerol as a potential green solvent for chemical reactions, a starting raw material for chemical and biochemical conversions into value-added chemicals, a substrate or co-substrate in microbial fermentations for synthesis of valuable chemicals and production of biogas and biohydrogen as well as a feedstuff for animal feed. A special attention is paid to various uses of crude glycerol in biodiesel production. [Projekat Ministarstva nauke Republike Srbije, br. III 45001

  10. Efficient green methanol synthesis from glycerol.

    Science.gov (United States)

    Haider, Muhammad H; Dummer, Nicholas F; Knight, David W; Jenkins, Robert L; Howard, Mark; Moulijn, Jacob; Taylor, Stuart H; Hutchings, Graham J

    2015-12-01

    The production of biodiesel from the transesterification of plant-derived triglycerides with methanol has been commercialized extensively. Impure glycerol is obtained as a by-product at roughly one-tenth the mass of the biodiesel. Utilization of this crude glycerol is important in improving the viability of the overall process. Here we show that crude glycerol can be reacted with water over very simple basic or redox oxide catalysts to produce methanol in high yields, together with other useful chemicals, in a one-step low-pressure process. Our discovery opens up the possibility of recycling the crude glycerol produced during biodiesel manufacture. Furthermore, we show that molecules containing at least two hydroxyl groups can be converted into methanol, which demonstrates some aspects of the generality of this new chemistry.

  11. Enhanced enzymatic saccharification of pretreated biomass using glycerol thermal processing (GTP).

    Science.gov (United States)

    Zhang, Wei; Sathitsuksanoh, Noppadon; Barone, Justin R; Renneckar, Scott

    2016-01-01

    Biomass was heated (200-240°C) in the presence of glycerol, for 4-12 min, under shear to disrupt the native cell wall architecture. The impact of this method, named glycerol thermal processing (GTP), on saccharification efficiency of the hardwood Liquidambar styraciflua, and a control cellulose sample was studied as a function of treatment severity. Furthermore, the enzymatic conversion of samples with varying compositions was studied after extraction of the structural polymers. Interestingly, the sweet gum processed materials crystallinity index increased by 10% of the initial value. The experiments revealed that the residual lignin was not a barrier to limiting the digestibility of cellulose after pretreatment yielding up to 70% glucose based on the starting wood material. Further xylan removal greatly improved the cellulose hydrolysis rate, converting nearly 70% of the cellulose into glucose within 24h, and reaching 78% of ultimate glucan digestibility after 72 h. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Monitoring of monosaccharides, oligosaccharides, ethanol and glycerol during wort fermentation by biosensors, HPLC and spectrophotometry.

    Science.gov (United States)

    Monošík, Rastislav; Magdolen, Peter; Stredanský, Miroslav; Šturdík, Ernest

    2013-05-01

    The aim of the present study was to analyze sugar levels (namely maltose, maltotriose, glucose and fructose) and alcohols (ethanol and glycerol) during the fermentation process in wort samples by amperometric enzymatic biosensors developed by our research group for industrial application, HPLC and spectrophotometry, and to compare the suitability of the presented methods for determination of individual analytes. We can conclude that for the specific monitoring of maltose or maltotriose only the HPLC method was suitable. On the other hand, biosensors and spectrophotometry reflected a decrease in total sugar concentration better and were able to detect both glucose and fructose in the later stages of fermentation, while HPLC was not. This can be attributed to the low detection limits and good sensitivity of the proposed methods. For the ethanol and glycerol analysis all methods proved to be suitable. However, concerning the cost expenses and time analysis, biosensors represented the best option. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Liquid dynamics in partially crystalline glycerol

    DEFF Research Database (Denmark)

    Sanz, Alejandro; Niss, Kristine

    2017-01-01

    influences the liquid dynamics visibly. For one of the samples studied, a tiny fraction of glycerol remained in the disordered state after the end of the transition. We examined the nature of the relaxation in this frustrated crystal and find that it is virtually identical to the bulk dynamics. In addition......, we have found no evidence that supercooled glycerol transforms into a peculiar phase in which either a new solid amorphous state or nano-crystals dispersed in a liquid matrix are formed....

  14. Poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) scaffolds coated with PhaP-RGD fusion protein promotes the proliferation and chondrogenic differentiation of human umbilical cord mesenchymal stem cells in vitro.

    Science.gov (United States)

    Li, Xiaoli; Chang, Huimin; Luo, Huanan; Wang, Zhenghui; Zheng, Guoxi; Lu, Xiaoyun; He, Xijing; Chen, Fang; Wang, Ting; Liang, Jianmin; Xu, Min

    2015-03-01

    Human umbilical cord blood-derived mesenchymal stem cells (hUC-MSCs) have been widely used in tissue engineering. The aim of this study is to evaluate the ability of poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) scaffolds coated with polyhydroxyalkanoate binding protein fused with arginyl-glycyl-aspartic acid (PhaP-RGD) to promote the proliferation and chondrogenic differentiation of hUC-MSCs seeded on them. The PhaP-RGD fusion protein was expressed by Escherichia coli. PHBHHx films were coated with PhaP-RGD fusion protein and the physiochemical properties were examined. hUC-MSCs were seeded on PHBHHx films with or without PhaP-RGD precoating and tested for changes in morphology, viability, and chondrogenic differentiation. We found that PhaP-RGD-coated PHBHHx films had similar surface morphology to uncoated PHBHHx. The water contact angle of the coated PHBHHx surface was lower than that of the uncoated surface (10.63° vs. 98.69°). At 7 and 14 days after seeding, the PhaP-RGD-coated PHBHHx group showed greater numbers of viable cells compared to the uncoated PHBHHx group. The expression levels of aggrecan and collagen II were enhanced in the PhaP-RGD-coated PHBHHx group relative to the uncoated PHBHHx group. Histological analysis using toluidine blue staining showed elevated formation of proteoglycan producing chondrocytes in the PhaP-RGD-coated PHBHHx group. Additionally, the synthesis of proteoglycan and collagen was significantly enhanced within the PhaP-RGD constructs. Taken together, PhaP-RGD coating promotes the proliferation and chondrogenic differentiation of hUC-MSCs seeded on PHBHHx films. PhaP-RGD-coated PHBHHx may be a useful scaffold for cartilage tissue engineering. © 2014 Wiley Periodicals, Inc.

  15. Integration of poly-3-(hydroxybutyrate-co-hydroxyvalerate) production by Haloferax mediterranei through utilization of stillage from rice-based ethanol manufacture in India and its techno-economic analysis.

    Science.gov (United States)

    Bhattacharyya, Anirban; Jana, Kuntal; Haldar, Saubhik; Bhowmic, Asit; Mukhopadhyay, Ujjal Kumar; De, Sudipta; Mukherjee, Joydeep

    2015-05-01

    Haloferax mediterranei has potential for economical industrial-scale production of polyhydroxyalkanoate (PHA) as it can utilize cheap carbon sources, has capacity for nonsterile cultivation and allows simple product recovery. Molasses-based Indian distilleries are converting themselves to cereal-based distilleries. Waste stillage (14 l) of rice-based ethanol industry was used for the production of PHA by H. mediterranei in the simple plug-flow reactor configuration of the activated sludge process. Cells utilized stillage and accumulated 63 ± 3 % PHA of dry cell weight and produced 13.12 ± 0.05 g PHA/l. The product yield coefficient was 0.27 while 0.14 g/l h volumetric productivity was reached. Simultaneous lowering of 5-day biochemical oxygen demand and chemical oxygen demand values of stillage by 82 % was attained. The biopolymer was characterized as poly-3-(hydroxybutyrate-co-17.9 mol%-hydroxyvalerate) (PHBV). Directional properties of decanoic acid jointly with temperature-dependent water solubility in decanoic acid were employed for two-step desalination of the spent stillage medium in a cylindrical baffled-tank with an immersed heater and a stirrer holding axial and radial impellers. 99.3 % of the medium salts were recovered and re-used for PHA production. The cost of PHBV was estimated as US$2.05/kg when the annual production was simulated as 1890 tons. Desalination contributed maximally to the overall cost. Technology and cost-analysis demonstrate that PHA production integrated with ethanol manufacture is feasible in India. This study could be the basis for construction of a pilot plant.

  16. Searching for branched glycerol dialkyl glycerol tetraether membrane lipid producing bacteria in soil

    NARCIS (Netherlands)

    Aydin, R.

    2012-01-01

    KEYWORDS:Branched GDGTs, proxy, pH, temperature, Acidobacteria, methylotrophy, high-throughput techniques

    Bacteria present in soil and peat bog environments were previously found to produce branched glycerol dialkyl glycerol

  17. Searching for branched glycerol dialkyl glycerol tetraether membrane lipid producing bacteria in soil

    NARCIS (Netherlands)

    Aydin, R.

    2012-01-01

    KEYWORDS:Branched GDGTs, proxy, pH, temperature, Acidobacteria, methylotrophy, high-throughput techniques Bacteria present in soil and peat bog environments were previously found to produce branched glycerol dialkyl glycerol tetraether membrane

  18. Effects of Paljeongsan-gamibang on the damage of Rat Kidney induced by Glycerol

    OpenAIRE

    Wang-Su Yun; Kyung-Son Soh; Chan-Gil Jeong

    2007-01-01

    Objective : We performed this study in order to investigate the effects of Paljeongsan-gamibang(八正散加味方) on the renal failure. Methods : We injected 8ml/kg of 50% glycerol on the rats. And then administered Paljeongsan-gamibang extract ; 209mg/200g/day to sample group during 3 days and observed the body temperature, urine volume, stool volume and the levels of creatinine, glucose, inorganic phosphorus, Na+, K+, Cl-, threonine, tyrosine in blood and creatinine, glucose, threonine, tyrosine i...

  19. Glycerol as a Cheaper Carbon Source in Bacterial Cellulose (BC) Production by Gluconacetobacter Xylinus DSM46604 in Batch Fermentation System

    International Nuclear Information System (INIS)

    Azila Adnan; Nair, G.R.; Roslan Umar; Roslan Umar

    2015-01-01

    Bacterial cellulose (BC) is a polymer of glucose monomers, which has unique properties including high crystallinity and high strength. It has potential to be used in biomedical applications such as making artificial blood vessel, wound dressings, and in the paper making industry. Extensive study on BC aimed to improve BC production such as by using glycerol as a cheaper carbon source. BC was produced in shake flask culture using five different concentrations of glycerol (10, 20, 30, 40 and 50 g/ L). Using concentration of glycerol above 20 g/ L inhibited culture growth and BC production. Further experiments were performed in batch culture (3-L bioreactor) using 20 g/ L glycerol. It produced yield and productivity of 0.15 g/ g and 0.29 g/ L/ day BC, respectively. This is compared with the control medium, 50 g/ L glucose, which only gave yield and productivity of 0.05 g/ g and 0.23 g/ L/ day, respectively. Twenty g/ L of glycerol enhanced BC production by Gluconacetobacter xylinus DSM46604 in batch fermentation system. (author)

  20. Minimization of glycerol synthesis in industrial ethanol yeast without influencing its fermentation performance.

    Science.gov (United States)

    Guo, Zhong-peng; Zhang, Liang; Ding, Zhong-yang; Shi, Gui-yang

    2011-01-01

    To synthesize glycerol, a major by-product during anaerobic production of ethanol, the yeast Saccharomyces cerevisiae would consume up to 4% of the sugar feedstock in typical industrial ethanol processes. The present study was dedicated to decreasing the glycerol production mostly in industrial ethanol producing yeast without affecting its desirable fermentation properties including high osmotic and ethanol tolerance, natural robustness in industrial processes. In the present study, the GPD1 gene, encoding NAD+-dependent glycerol-3-phosphate dehydrogenase in an industrial ethanol producing strain of S. cerevisiae, was deleted. Simultaneously, a non-phosphorylating NADP+-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPN) from Bacillus cereus was expressed in the mutant deletion of GPD1. Although the resultant strain AG1A (gpd1△ P(PGK)-gapN) exhibited a 48.7±0.3% (relative to the amount of substrate consumed) lower glycerol yield and a 7.6±0.1% (relative to the amount of substrate consumed) higher ethanol yield compared to the wild-type strain, it was sensitive to osmotic stress and failed to ferment on 25% glucose. However, when trehalose synthesis genes TPS1 and TPS2 were over-expressed in the above recombinant strain AG1A, its high osmotic stress tolerance was not only restored but also improved. In addition, this new recombinant yeast strain displayed further reduced glycerol yield, indistinguishable maximum specific growth rate (μ(max)) and fermentation ability compared to the wild type in anaerobic batch fermentations. This study provides a promising strategy to improve ethanol yields by minimization of glycerol production. © 2010 Elsevier Inc. All rights reserved.

  1. Catalytic glycerol steam reforming for hydrogen production

    International Nuclear Information System (INIS)

    Dan, Monica; Mihet, Maria; Lazar, Mihaela D.

    2015-01-01

    Hydrogen production from glycerol by steam reforming combine two major advantages: (i) using glycerol as raw material add value to this by product of bio-diesel production which is obtained in large quantities around the world and have a very limited utilization now, and (ii) by implication of water molecules in the reaction the efficiency of hydrogen generation is increased as each mol of glycerol produces 7 mol of H 2 . In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al 2 O 3 . The catalyst was prepared by wet impregnation method and characterized through different methods: N 2 adsorption-desorption, XRD, TPR. The catalytic study was performed in a stainless steel tubular reactor at atmospheric pressure by varying the reaction conditions: steam/carbon ratio (1-9), gas flow (35 ml/min -133 ml/min), temperature (450-650°C). The gaseous fraction of the reaction products contain: H 2 , CH 4 , CO, CO 2 . The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H 2 O ratio 9:1 and Ar flow 133 ml/min. In these conditions the glycerol conversion to gaseous products was 43% and the hydrogen yield was 30%

  2. Potential of a newly developed high-speed near-infrared (NIR) camera (Compovision) in polymer industrial analyses: monitoring crystallinity and crystal evolution of polylactic acid (PLA) and concentration of PLA in PLA/Poly-(R)-3-hydroxybutyrate (PHB) blends.

    Science.gov (United States)

    Ishikawa, Daitaro; Nishii, Takashi; Mizuno, Fumiaki; Sato, Harumi; Kazarian, Sergei G; Ozaki, Yukihiro

    2013-12-01

    This study was carried out to evaluate a new high-speed hyperspectral near-infrared (NIR) camera named Compovision. Quantitative analyses of the crystallinity and crystal evolution of biodegradable polymer, polylactic acid (PLA), and its concentration in PLA/poly-(R)-3-hydroxybutyrate (PHB) blends were investigated using near-infrared (NIR) imaging. This NIR camera can measure two-dimensional NIR spectral data in the 1000-2350 nm region obtaining images with wide field of view of 150 × 250 mm(2) (approximately 100  000 pixels) at high speeds (in less than 5 s). PLA with differing crystallinities between 0 and 50% blended samples with PHB in ratios of 80/20, 60/40, 40/60, 20/80, and pure films of 100% PLA and PHB were prepared. Compovision was used to collect respective NIR spectra in the 1000-2350 nm region and investigate the crystallinity of PLA and its concentration in the blends. The partial least squares (PLS) regression models for the crystallinity of PLA were developed using absorbance, second derivative, and standard normal variate (SNV) spectra from the most informative region of the spectra, between 1600 and 2000 nm. The predicted results of PLS models achieved using the absorbance and second derivative spectra were fairly good with a root mean square error (RMSE) of less than 6.1% and a determination of coefficient (R(2)) of more than 0.88 for PLS factor 1. The results obtained using the SNV spectra yielded the best prediction with the smallest RMSE of 2.93% and the highest R(2) of 0.976. Moreover, PLS models developed for estimating the concentration of PLA in the blend polymers using SNV spectra gave good predicted results where the RMSE was 4.94% and R(2) was 0.98. The SNV-based models provided the best-predicted results, since it can reduce the effects of the spectral changes induced by the inhomogeneity and the thickness of the samples. Wide area crystal evolution of PLA on a plate where a temperature slope of 70-105 °C had occurred was also

  3. Vascular Endothelial Growth Factor Improves Physico-Mechanical Properties and Enhances Endothelialization of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/Poly(ε-caprolactone) Small-Diameter Vascular Grafts In vivo.

    Science.gov (United States)

    Antonova, Larisa V; Sevostyanova, Victoria V; Kutikhin, Anton G; Mironov, Andrey V; Krivkina, Evgeniya O; Shabaev, Amin R; Matveeva, Vera G; Velikanova, Elena A; Sergeeva, Evgeniya A; Burago, Andrey Y; Vasyukov, Georgiy Y; Glushkova, Tatiana V; Kudryavtseva, Yuliya A; Barbarash, Olga L; Barbarash, Leonid S

    2016-01-01

    The combination of a natural polymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and a synthetic hydrophobic polymer poly(ε-caprolactone) (PCL) is promising for the preparation of biodegradable and biocompatible small-diameter vascular grafts for bypass surgery. However, physico-mechanical properties and endothelialization rate of PHBV/PCL grafts are poor. We suggested that incorporation of vascular endothelial growth factor (VEGF) into PHBV/PCL grafts may improve their physico-mechanical properties and enhance endothelialization. Here we compared morphology, physico-mechanical properties, and in vivo performance of electrospun small-diameter vascular grafts prepared from PHBV/PCL with and without VEGF. Structure of the graft surface and physico-mechanical properties were examined by scanning electron microscopy and universal testing machine, respectively. Grafts were implanted into rat abdominal aorta for 1, 3, and 6 months with the further histological, immunohistochemical, and immunofluorescence examination. PHBV/PCL grafts with and without VEGF were highly porous and consisted mostly of nanoscale and microscale fibers, respectively. Mean pore diameter and mean pore area were significantly lower in PHBV/PCL/VEGF compared to PHBV/PCL grafts (1.47 μm and 10.05 μm(2); 2.63 μm and 47.13 μm(2), respectively). Durability, elasticity, and stiffness of PHBV/PCL grafts with VEGF were more similar to internal mammary artery compared to those without, particularly 6 months postimplantation. Both qualitative examination and quantitative image analysis showed that three-fourths of PHBV/PCL grafts with VEGF were patent and had many CD31-, CD34-, and vWF-positive cells at their inner surface. However, all PHBV/PCL grafts without VEGF were occluded and had no or a few CD31-positive cells at the inner surface. Therefore, VEGF enhanced endothelialization and improved graft patency at all the time points in a rat abdominal aorta replacement model. In conclusion, PHBV

  4. From Symmetric Glycerol Derivatives to Dissymmetric Chlorohydrins

    Directory of Open Access Journals (Sweden)

    Gemma Villorbina

    2011-03-01

    Full Text Available The anticipated worldwide increase in biodiesel production will result in an accumulation of glycerol for which there are insufficient conventional uses. The surplus of this by-product has increased rapidly during the last decade, prompting a search for new glycerol applications. We describe here the synthesis of dissymmetric chlorohydrin esters from symmetric 1,3-dichloro-2-propyl esters obtained from glycerol. We studied the influence of two solvents: 1,4-dioxane and 1-butanol and two bases: sodium carbonate and 1-butylimidazole, on the synthesis of dissymmetric chlorohydrin esters. In addition, we studied the influence of other bases (potassium and lithium carbonates in the reaction using 1,4-dioxane as the solvent. The highest yield was obtained using 1,4-dioxane and sodium carbonate.

  5. Metabolic and regulatory rearrangements underlying glycerol metabolism in Pseudomonas putida KT2440.

    Science.gov (United States)

    Nikel, Pablo I; Kim, Juhyun; de Lorenzo, Víctor

    2014-01-01

    While the natural niches of the soil bacterium Pseudomonas putida are unlikely to include significant amounts of free glycerol as a growth substrate, this bacterium is genetically equipped with the functions required for its metabolism. We have resorted to deep sequencing of the transcripts in glycerol-grown P. putida KT2440 cells to gain an insight into the biochemical and regulatory components involved in the shift between customary C sources (e.g. glucose or succinate) to the polyol. Transcriptomic results were contrasted with key enzymatic activities under the same culture conditions. Cognate expression profiles revealed that genes encoding enzymes of the Entner-Doudoroff route and other catabolic pathways, e.g. the gluconate and 2-ketogluconate loops, were significantly downregulated on glycerol. Yet, the compound simultaneously elicited a gluconeogenic response that indicated an efficient channelling of C skeletons back to biomass build-up through the glyoxylate shunt rather than energization of the cells through downwards pathways, i.e. tricarboxylic acid cycle and oxidative phosphorylation. The simultaneous glycolytic and gluconeogenic metabolic regimes on glycerol, paradoxical as they seem, make sense from an ecological point of view by favouring prevalence versus exploration. This metabolic situation was accompanied by a considerably low expression of stress markers as compared with other C sources. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. Tandem transformation of glycerol to esters.

    Science.gov (United States)

    Sotenko, Maria V; Rebroš, Martin; Sans, Victor S; Loponov, Konstantin N; Davidson, Matthew G; Stephens, Gill; Lapkin, Alexei A

    2012-12-31

    Tandem transformation of glycerol via microbial fermentation and enzymatic esterification is presented. The reaction can be performed with purified waste glycerol from biodiesel production in a continuous mode, combining continuous fermentation with membrane-supported enzymatic esterification. Continuous anaerobic fermentation was optimized resulting in the productivity of 2.4 g L⁻¹ h⁻¹ of 1,3-propanediol. Biphasic esterification of 1,3-propanediol was optimized to achieve ester yield of up to 75%. A hollow fibre membrane contactor with immobilized Rhizomucor miehei lipase was demonstrated for the continuous tandem fermentation-esterification process. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. New insights into Escherichia coli metabolism: carbon scavenging, acetate metabolism and carbon recycling responses during growth on glycerol

    Directory of Open Access Journals (Sweden)

    Martínez-Gómez Karla

    2012-07-01

    Full Text Available Abstract Background Glycerol has enhanced its biotechnological importance since it is a byproduct of biodiesel synthesis. A study of Escherichia coli physiology during growth on glycerol was performed combining transcriptional-proteomic analysis as well as kinetic and stoichiometric evaluations in the strain JM101 and certain derivatives with important inactivated genes. Results Transcriptional and proteomic analysis of metabolic central genes of strain JM101 growing on glycerol, revealed important changes not only in the synthesis of MglB, LamB and MalE proteins, but also in the overexpression of carbon scavenging genes: lamB, malE, mglB, mglC, galP and glk and some members of the RpoS regulon (pfkA, pfkB, fbaA, fbaB, pgi, poxB, acs, actP and acnA. Inactivation of rpoS had an important effect on stoichiometric parameters and growth adaptation on glycerol. The observed overexpression of poxB, pta, acs genes, glyoxylate shunt genes (aceA, aceB, glcB and glcC and actP, suggested a possible carbon flux deviation into the PoxB, Acs and glyoxylate shunt. In this scenario acetate synthesized from pyruvate with PoxB was apparently reutilized via Acs and the glyoxylate shunt enzymes. In agreement, no acetate was detected when growing on glycerol, this strain was also capable of glycerol and acetate coutilization when growing in mineral media and derivatives carrying inactivated poxB or pckA genes, accumulated acetate. Tryptophanase A (TnaA was synthesized at high levels and indole was produced by this enzyme, in strain JM101 growing on glycerol. Additionally, in the isogenic derivative with the inactivated tnaA gene, no indole was detected and acetate and lactate were accumulated. A high efficiency aromatic compounds production capability was detected in JM101 carrying pJLBaroGfbrtktA, when growing on glycerol, as compared to glucose. Conclusions The overexpression of several carbon scavenging, acetate metabolism genes and the absence of acetate

  8. Investigation of glycerol assimilation and cofactor metabolism in Lactococcus lactis

    DEFF Research Database (Denmark)

    Holm, Anders Koefoed

    : anaerobic, aerobic and respiration permissive growth in combination with either glycerol as a sole substrate or with co-metabolization of glycerol with common sugar substrates. Although no growth on glycerol was seen, both positive and detrimental effects were observed from cultures with glycerol...... itself under both anaerobic and respiration permissive conditions, but was not found to have the same profound effect on other sugar substrates such as galactose or ribose. Supplementation of nucleosides to the growth medium or increased substrate concentration were found to counteract the inhibitory...... of glycerol kinase from L. lactis, introduction of a heterologous glycerol assimilation pathway and construction of a library of NADH oxidase activity. Based on a preliminary analysis of transcription level data, an attempt was made to stimulate glycerol assimilation by overexpressing the glycerol kinase...

  9. Insulin regulation of renal glucose metabolism in conscious dogs.

    Science.gov (United States)

    Cersosimo, E; Judd, R L; Miles, J M

    1994-01-01

    Previous studies indicating that postabsorptive renal glucose production is negligible used the net balance technique, which cannot partition simultaneous renal glucose production and glucose uptake. 10 d after surgical placement of sampling catheters in the left renal vein and femoral artery and a nonobstructive infusion catheter in the left renal artery of dogs, systemic and renal glucose and glycerol kinetics were measured with peripheral infusions of [3-3H]glucose and [2-14C]glycerol. After baseline measurements, animals received a 2-h intrarenal infusion of either insulin (n = 6) or saline (n = 6). Left renal vein insulin concentration increased from 41 +/- 8 to 92 +/- 23 pmol/l (P gluconeogenesis from glycerol decreased from 0.23 +/- 0.06 to 0.17 +/- 0.04 mumol.kg-1.min-1 (P dogs. Physiological hyperinsulinemia suppresses renal glucose production and stimulates renal glucose uptake by approximately 75%. We conclude that the kidney makes a major contribution to systemic glucose metabolism in the postabsorptive state. PMID:8200996

  10. Glycerol hypersensitivity in a Drosophila model for glycerol kinase deficiency is affected by mutations in eye pigmentation genes.

    Directory of Open Access Journals (Sweden)

    Patrick J Wightman

    Full Text Available Glycerol kinase plays a critical role in metabolism by converting glycerol to glycerol 3-phosphate in an ATP dependent reaction. In humans, glycerol kinase deficiency results in a wide range of phenotypic variability; patients can have severe metabolic and CNS abnormalities, while others possess hyperglycerolemia and glyceroluria with no other apparent phenotype. In an effort to help understand the pathogenic mechanisms underlying the phenotypic variation, we have created a Drosophila model for glycerol kinase deficiency by RNAi targeting of dGyk (CG18374 and dGK (CG7995. As expected, RNAi flies have reduced glycerol kinase RNA expression, reduced phosphorylation activity and elevated glycerol levels. Further investigation revealed these flies to be hypersensitive to fly food supplemented with glycerol. Due to the hygroscopic nature of glycerol, we predict glycerol hypersensitivity is a result of greater susceptibility to desiccation, suggesting glycerol kinase to play an important role in desiccation resistance in insects. To evaluate a role for genetic modifier loci in determining severity of the glycerol hypersensitivity observed in knockdown flies, we performed a preliminary screen of lethal transposon insertion mutant flies using a glycerol hypersensitive survivorship assay. We demonstrate that this type of screen can identify both enhancer and suppressor genetic loci of glycerol hypersensitivity. Furthermore, we found that the glycerol hypersensitivity phenotype can be enhanced or suppressed by null mutations in eye pigmentation genes. Taken together, our data suggest proteins encoded by eye pigmentation genes play an important role in desiccation resistance and that eye pigmentation genes are strong modifiers of the glycerol hypersensitive phenotype identified in our Drosophila model for glycerol kinase deficiency.

  11. Glycerol Hypersensitivity in a Drosophila Model for Glycerol Kinase Deficiency Is Affected by Mutations in Eye Pigmentation Genes

    Science.gov (United States)

    Wightman, Patrick J.; Jackson, George R.; Dipple, Katrina M.

    2012-01-01

    Glycerol kinase plays a critical role in metabolism by converting glycerol to glycerol 3-phosphate in an ATP dependent reaction. In humans, glycerol kinase deficiency results in a wide range of phenotypic variability; patients can have severe metabolic and CNS abnormalities, while others possess hyperglycerolemia and glyceroluria with no other apparent phenotype. In an effort to help understand the pathogenic mechanisms underlying the phenotypic variation, we have created a Drosophila model for glycerol kinase deficiency by RNAi targeting of dGyk (CG18374) and dGK (CG7995). As expected, RNAi flies have reduced glycerol kinase RNA expression, reduced phosphorylation activity and elevated glycerol levels. Further investigation revealed these flies to be hypersensitive to fly food supplemented with glycerol. Due to the hygroscopic nature of glycerol, we predict glycerol hypersensitivity is a result of greater susceptibility to desiccation, suggesting glycerol kinase to play an important role in desiccation resistance in insects. To evaluate a role for genetic modifier loci in determining severity of the glycerol hypersensitivity observed in knockdown flies, we performed a preliminary screen of lethal transposon insertion mutant flies using a glycerol hypersensitive survivorship assay. We demonstrate that this type of screen can identify both enhancer and suppressor genetic loci of glycerol hypersensitivity. Furthermore, we found that the glycerol hypersensitivity phenotype can be enhanced or suppressed by null mutations in eye pigmentation genes. Taken together, our data suggest proteins encoded by eye pigmentation genes play an important role in desiccation resistance and that eye pigmentation genes are strong modifiers of the glycerol hypersensitive phenotype identified in our Drosophila model for glycerol kinase deficiency. PMID:22427807

  12. Preparation of silver powder through glycerol process

    Indian Academy of Sciences (India)

    Unknown

    These in- clude reduction of silver salts by NaBH4, HCHO/NaOH/ ... solid inorganic/organic salt of metal is suspended in a liquid polyol, the suspension is stirred and heated to a given temperature. The reduction of metallic salt by polyol quantitatively ... Though the solubility of silver nitrate in glycerol at room temperature is ...

  13. Conversion of glycerol to hydrogen rich gas.

    Science.gov (United States)

    Tran, Nguyen H; Kannangara, G S Kamali

    2013-12-21

    Presently there is a glut of glycerol as the by-product of biofuel production and it will grow as production increases. The conundrum is how we can consume this material and convert it into a more useful product. One potential route is to reform glycerol to hydrogen rich gas including synthesis gas (CO + H2) and hydrogen. However, there is recent literature on various reforming techniques which may have a bearing on the efficiency of such a process. Hence in this review reforming of glycerol at room temperature (normally photo-catalytic), catalysis at moderate and high temperature and a non-catalytic pyrolysis process are presented. The high temperature processes allow the generation of synthesis gas with the hydrogen to carbon monoxide ratios being suitable for synthesis of dimethyl ether, methanol and for the Fischer-Tropsch process using established catalysts. Efficient conversion of synthesis gas to hydrogen involves additional catalysts that assist the water gas shift reaction, or involves in situ capture of carbon dioxide and hydrogen. Reforming at reduced temperatures including photo-reforming offers the opportunity of producing synthesis gas or hydrogen using single catalysts. Together, these processes will assist in overcoming the worldwide glut of glycerol, increasing the competitiveness of the biofuel production and reducing our dependency on the fossil based, hydrogen rich gas.

  14. Synthesis of prebiotic glycerol in interstellar ices.

    Science.gov (United States)

    Kaiser, Ralf I; Maity, Surajit; Jones, Brant M

    2015-01-02

    Contemporary mechanisms for the spontaneous formation of glycerol have not been able to explain its existence on early Earth. The exogenous origin and delivery of organic molecules to early Earth presents an alternative route to their terrestrial in situ formation since biorelevant molecules like amino acids, carboxylic acids, and alkylphosphonic acids have been recovered from carbonaceous chondrites. Reported herein is the first in situ identification of glycerol, the key building block of all cellular membranes, formed by exposure of methanol-based - interstellar model ices to ionizing radiation in the form of energetic electrons. These results provide compelling evidence that the radiation-induced formation of glycerol in low-temperature interstellar model ices is facile. Synthesized on interstellar grains and eventually incorporated into the "building material" of solar systems, biorelevant molecules such as glycerol could have been dispensed to habitable planets such as early Earth by comets and meteorites. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. METHYLENE BLUE ADSORPTION FROM GLYCEROL SOLUTION ...

    African Journals Online (AJOL)

    Preferred Customer

    ABSTRACT. The mechanism of methylene blue adsorption onto the surface of synthetic acicular habit of α- goethite from glycerol solution has been studied through batch experiment at 25, 30 and 35 0C in a glass cell of minimal dead volume. To describe the adsorption results, an attempt was made to fit the data to the ...

  16. Determining Atmospheric Pressure with a Eudiometer and Glycerol

    Science.gov (United States)

    Brody, Jed; Rohald, Kate; Sutton, Atasha

    2010-01-01

    We consider a volume of air trapped over a glycerol column in a eudiometer. We demonstrate that there is an approximately linear relationship between the volume of trapped air and the height of the glycerol column. Simply by moving the eudiometer up and down, we cause the glycerol-column height and trapped-air volume to vary. The plot of volume…

  17. Synthesis of glycerol mono-laurate from lauric acid and glycerol for food antibacterial additive

    Science.gov (United States)

    Setianto, W. B.; Wibowo, T. Y.; Yohanes, H.; Illaningtyas, F.; Anggoro, D. D.

    2017-05-01

    Synthesis of glycerol mono-laurate (GML) has been performed using esterification reaction of glycerol and lauric acid. The reaction was performed at the condition of temperature of 120-140 °C within 7 hour, variation of molar ratio of glycerol - lauric acid, and was using heterogeneous catalyst of zeolist Y. Without catalyst dealumination the maximum acid conversion was 78%, with GML contained in the sample was 38.6%, and it was obtained at the reaction condition of 140 oC, 15wt% catalyst, and 8:1 molar ratio of glycerol - lauric acid. At the same condition, using dealuminated catalyst, the maximum acid conversion was increased up to 98%, with GML contained in the sample was 50.4%. The GML antibacterial activity was examined. It was observed that the GML has antibacterial activity against gram positive bacterial such as B. cereus and S. aureus.

  18. Clinical heterogeneity and novel mutations in the glycerol kinase gene in three families with isolated glycerol kinase deficiency

    NARCIS (Netherlands)

    Sjarif, D. R.; Sinke, R. J.; Duran, M.; Beemer, F. A.; Kleijer, W. J.; Ploos van Amstel, J. K.; Poll-The, B. T.

    1998-01-01

    Isolated glycerol kinase deficiency (GKD) is an X linked recessive disorder. The clinical and biochemical picture may vary from a childhood metabolic crisis to asymptomatic adult "pseudohypertriglyceridaemia", the result of hyperglycerolaemia. We performed glycerol kinase (GK) gene analysis to study

  19. Glycerol dialkyl glycerol tetraether membrane lipids in lacustrine environments and their application as proxies for palaeoclimate reconstructions. Geologica Ultraiectina (322)

    NARCIS (Netherlands)

    Blaga, C.I.

    2010-01-01

    Lacustrine sediments often contain relatively high amounts of organic matter because of limited bottom water oxygenation and relatively high sedimentation rates. The membrane lipids of Crenarchaeota, a major group of the domain Archaea, consist of isoprenoid glycerol dialkyl glycerol tetraether

  20. Glucose Sensing

    CERN Document Server

    Geddes, Chris D

    2006-01-01

    Topics in Fluorescence Spectroscopy, Glucose Sensing is the eleventh volume in the popular series Topics in Fluorescence Spectroscopy, edited by Drs. Chris D. Geddes and Joseph R. Lakowicz. This volume incorporates authoritative analytical fluorescence-based glucose sensing reviews specialized enough to be attractive to professional researchers, yet also appealing to the wider audience of scientists in related disciplines of fluorescence. Glucose Sensing is an essential reference for any lab working in the analytical fluorescence glucose sensing field. All academics, bench scientists, and industry professionals wishing to take advantage of the latest and greatest in the continuously emerging field of glucose sensing, and diabetes care & management, will find this volume an invaluable resource. Topics in Fluorescence Spectroscopy Volume 11, Glucose Sensing Chapters include: Implantable Sensors for Interstitial Fluid Smart Tattoo Glucose Sensors Optical Enzyme-based Glucose Biosensors Plasmonic Glucose Sens...

  1. The solvent-tolerant Pseudomonas putida S12 as host for the production of cinnamic acid from glucose

    NARCIS (Netherlands)

    Nijkamp, K.; Luijk, N. van; Bont, J.A.M. de; Wery, J.

    2005-01-01

    A Pseudomonas putida S12 strain was constructed that efficiently produced thefine chemical cinnamic acid from glucose or glycerol via the central metabolite phenylalanine. The gene encoding phenylalanine ammonia lyase from the yeast Rhodosporidium toruloides was introduced. Phenylalanine

  2. Beneficial Effect of Paljeong-san Pharmacopuncture Treatment Combined with Peritoneal Injection on Glycerol-Induced Acute Renal Failure in Rabbits

    Directory of Open Access Journals (Sweden)

    Chi-Yeon Lim

    2010-09-01

    Full Text Available Purpose: The present study was carried out to determine if Paljeong-san extract (PJS treatment exerts beneficial effect against the glycerol-induced acute renal failure in rabbits. Material and Method: PJS was selected in the basis of invigorating kidney which can eliminate pathogens. Rabbits were treated with PJS pharmacopuncture on Shin-shu (BL23 point for 5 days right after the injection of 50% concentration of glycerol (5㎖/㎏ body weight. Results and Conclusions: Glycerol injection caused an increase in serum creatinine and BUN level and urine glucose secretion, which were accompanied by a reduction in GFR. PJS Pharmacopuncture treatment combined with peritoneal injection showed beneficial effect on glycerol-induced acute renal failure by inhibition of serum creatinine increase and GFR decrease.

  3. Production of Microbial Transglutaminase on Media Made from Sugar Cane Molasses and Glycerol

    Directory of Open Access Journals (Sweden)

    Manuel Vázquez

    2009-01-01

    Full Text Available Transglutaminase is an enzyme that catalyses an acyl transfer reaction between γ-carboxamide groups of glutaminyl residues and lysine residues in proteins. Due to this property, this enzyme is used for enhancing textural properties of protein-rich food. The transglutaminase used as food additive is obtained by microorganisms, mainly by Streptoverticillium ladakanum. On the other hand, sugar cane molasses is a viscous liquid rich in noncrystallized carbohydrates (saccharose, glucose and fructose. In this work, the feasibility of using sugar cane molasses as a carbon source for the production of microbial transglutaminase by Streptoverticillium ladakanum NRRL 3191 has been studied. Carbon sources including sugar cane molasses (60 g of total sugars per L, glycerol (60 g/L and their mixture in a ratio of 1:1 (30 g/L of each were evaluated. Time course of microbial growth, transglutaminase activity and carbon source consumption were determined every 24 h during 120 h of fermentations at three agitation speeds (200, 300 or 400 rpm. The results showed that with the increase in agitation speed, the biomass concentration increased up to 8.39 g/L in the medium containing sugar cane molasses alone or the mixture of molasses and glycerol. The highest transglutaminase activity was obtained at 400 rpm in the medium containing a mixture of molasses and glycerol, reaching 0.460 U/mL, while in the medium containing sugar cane molasses alone, the activity was 0.240 U/mL, and using glycerol alone it was 0.250 U/mL. These results show that sugar cane molasses is a suitable medium for transglutaminase production when it is combined with glycerol.

  4. Glycerol from biodiesel production: the new corn for dairy cattle

    Directory of Open Access Journals (Sweden)

    Shawn S Donkin

    2008-07-01

    Full Text Available Glycerol, also known as glycerin, is a colorless, odorless, hygroscopic, and sweet-tasting viscous liquid. It is a sugar alcohol with high solubility index in water and has a wide range of applications in the food, pharmaceutical, and cosmetic industries. The use of glycerol in diets for dairy cattle is not novel; however, this interest has been renewed due to the increased availability and favorable pricing of glycerol as a consequence of recent growth in the biofuels industry. Experimental evidence supports the use of glycerol as a transition cow therapy but feeding rates are low, ranging from 5 to 8 % of the diet DM. There is a paucity of research that examines the use of glycerol as a macro-ingredient in rations for lactating dairy cows. Most reports indicate a lack of effect of addition of glycerol to the diet when it replaces corn or corn starch. Recent feeding experiments with lactating dairy cows indicate replacing corn with glycerol to a level of 15% of the ration DM does not adversely effect milk production or composition. Milk production was 37.0, 36.9, 37.3, 36.4 ± 0.6 kg/d and feed intake was 24.0, 24.5, 24.6, 24.1 ± 0.5 kg/d for 0, 5, 10 and 15% glycerol treatments respectively and did not differ (P > 0.05 except for a modest reduction in feed intake during the first 7 days for the 15% glycerol treatment. Glycerol fed to dairy cattle is fermented to volatile fatty acids in the rumen and early reports indicated that glycerol is almost entirely fermented to propionate. In vitro data indicates glycerol fermentation increases the production of propionate and butyrate at the expense of acetate. Rumen microbes appear to adapt to glycerol feeding and consequently, cows fed glycerol also require an adaptation period to glycerol inclusion. Debate exists regarding the fate of glycerol in the rumen and although most reports suggest that glycerol is largely fermented in the rumen, the extent of rumen digestion may depend on level of

  5. Glycerol stress in Saccharomyces cerevisiae: Cellular responses and evolved adaptations.

    Science.gov (United States)

    Mattenberger, Florian; Sabater-Muñoz, Beatriz; Hallsworth, John E; Fares, Mario A

    2017-03-01

    Glycerol synthesis is key to central metabolism and stress biology in Saccharomyces cerevisiae, yet the cellular adjustments needed to respond and adapt to glycerol stress are little understood. Here, we determined impacts of acute and chronic exposures to glycerol stress in S. cerevisiae. Glycerol stress can result from an increase of glycerol concentration in the medium due to the S. cerevisiae fermenting activity or other metabolic activities. Acute glycerol-stress led to a 50% decline in growth rate and altered transcription of more than 40% of genes. The increased genetic diversity in S. cerevisiae population, which had evolved in the standard nutrient medium for hundreds of generations, led to an increase in growth rate and altered transcriptome when such population was transferred to stressful media containing a high concentration of glycerol; 0.41 M (0.990 water activity). Evolution of S. cerevisiae populations during a 10-day period in the glycerol-containing medium led to transcriptome changes and readjustments to improve control of glycerol flux across the membrane, regulation of cell cycle, and more robust stress response; and a remarkable increase of growth rate under glycerol stress. Most of the observed regulatory changes arose in duplicated genes. These findings elucidate the physiological mechanisms, which underlie glycerol-stress response, and longer-term adaptations, in S. cerevisiae; they also have implications for enigmatic aspects of the ecology of this otherwise well-characterized yeast. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. The expression of glycerol facilitators from various yeast species improves growth on glycerol ofSaccharomyces cerevisiae.

    Science.gov (United States)

    Klein, Mathias; Islam, Zia-Ul; Knudsen, Peter Boldsen; Carrillo, Martina; Swinnen, Steve; Workman, Mhairi; Nevoigt, Elke

    2016-12-01

    Glycerol is an abundant by-product during biodiesel production and additionally has several assets compared to sugars when used as a carbon source for growing microorganisms in the context of biotechnological applications. However, most strains of the platform production organism Saccharomyces cerevisiae grow poorly in synthetic glycerol medium. It has been hypothesized that the uptake of glycerol could be a major bottleneck for the utilization of glycerol in S. cerevisiae . This species exclusively relies on an active transport system for glycerol uptake. This work demonstrates that the expression of predicted glycerol facilitators (Fps1 homologues) from superior glycerol-utilizing yeast species such as Pachysolen tannophilus , Komagataella pastoris , Yarrowia lipolytica and Cyberlindnera jadinii significantly improves the growth performance on glycerol of the previously selected glycerol-consuming S. cerevisiae wild-type strain (CBS 6412-13A). The maximum specific growth rate increased from 0.13 up to 0.18 h -1 and a biomass yield coefficient of 0.56 g DW /g glycerol was observed. These results pave the way for exploiting the assets of glycerol in the production of fuels, chemicals and pharmaceuticals based on baker's yeast.

  7. Effects of Paljeongsan-gamibang on the damage of Rat Kidney induced by Glycerol

    Directory of Open Access Journals (Sweden)

    Wang-Su Yun

    2007-02-01

    Full Text Available Objective : We performed this study in order to investigate the effects of Paljeongsan-gamibang(八正散加味方 on the renal failure. Methods : We injected 8ml/kg of 50% glycerol on the rats. And then administered Paljeongsan-gamibang extract ; 209mg/200g/day to sample group during 3 days and observed the body temperature, urine volume, stool volume and the levels of creatinine, glucose, inorganic phosphorus, Na+, K+, Cl-, threonine, tyrosine in blood and creatinine, glucose, threonine, tyrosine in urine. Results : 1, The sample group administered Paljeongsan-gamibang showed a suppressive effect of body temperature, an improving effect in capability of concentrating urine at convoluted tubule and showed an increasing effect of stool volume. 2. The sample group administered Paljeongsan-gamibang showed a lowering effect in creatinine level in blood and showed an increasing effect in the levels of inorganic phosphorus, Na+, K+, Cl-, threonine and tyrosine in blood. 3. The sample group administered Paljeongsan-gamibang showed an increasing effect in creatinine level in urine and showed a lowering effect in the levels of glucose, inorganic phosphorus, threonine and tyrosine in urine. Conclusions : Conclusively, Paljeongsan-gamibang was recognized to have a curative effect against the damage of rat kidney induced by 50% glycerol, especially to improve the capability of reabsorption in proximal convoluted tubule.

  8. Regulation of glucose utilization and lipogenesis in adipose tissue ...

    Indian Academy of Sciences (India)

    Unknown

    In order to evaluate the modulatory effects of manganese, high fat diet fed and alloxan diabetic rats were taken and the changes in the glucose oxidation, glycerol release and effects of manganese on these parameters were measured from adipose tissue. An insulin-mimetic effect of manganese was observed in the adipose ...

  9. Alteration of de novo glucose production contributes to fasting hypoglycaemia in Fyn deficient mice.

    Directory of Open Access Journals (Sweden)

    Yingjuan Yang

    Full Text Available Previous studies have demonstrated that glucose disposal is increased in the Fyn knockout (FynKO mice due to increased insulin sensitivity. FynKO mice also display fasting hypoglycaemia despite decreased insulin levels, which suggested that hepatic glucose production was unable to compensate for the increased basal glucose utilization. The present study investigates the basis for the reduction in plasma glucose levels and the reduced ability for the liver to produce glucose in response to gluconeogenic substrates. FynKO mice had a 5-fold reduction in phosphoenolpyruvate carboxykinase (PEPCK gene and protein expression and a marked reduction in pyruvate, pyruvate/lactate-stimulated glucose output. Remarkably, de novo glucose production was also blunted using gluconeogenic substrates that bypass the PEPCK step. Impaired conversion of glycerol to glucose was observed in both glycerol tolerance test and determination of the conversion of (13C-glycerol to glucose in the fasted state. α-glycerol phosphate levels were reduced but glycerol kinase protein expression levels were not changed. Fructose-driven glucose production was also diminished without alteration of fructokinase expression levels. The normal levels of dihydroxyacetone phosphate and glyceraldehyde-3-phosphate observed in the FynKO liver extracts suggested normal triose kinase function. Fructose-bisphosphate aldolase (aldolase mRNA or protein levels were normal in the Fyn-deficient livers, however, there was a large reduction in liver fructose-6-phosphate (30-fold and fructose-1,6-bisphosphate (7-fold levels as well as a reduction in glucose-6-phosphate (2-fold levels. These data suggest a mechanistic defect in the allosteric regulation of aldolase activity.

  10. Biological Conversion of Glycerol to Ethanol by Enterobacter aerogenes

    Science.gov (United States)

    Nwachukwu, Raymond E. S.

    In a search to turn the economically and environmentally non-valuable "waste" streams of biodiesel production into a profitable byproduct, a mutant strain of Enterobacter aerogenes ATCC 13048 was developed by six-tube subculturing technique. This technique is based on the principle of adaptive evolution, and involved subculturing the bacterium in a tryptic soy broth without dextrose (TSB) containing specific glycerol and ethanol concentration for six consecutive times. Then, the six consecutive subculturing was repeated in a fresh TSB of higher glycerol and ethanol concentrations. A new mutant strain, E. aerogenes S012, which could withstand a combination of 200 g/l glycerol and 30 g/l ethanol concentrations, was developed. The wild and mutant strains were used for the fermentation of pure (P-) and recovered (R-) glycerol. Taguchi and full factorial methods of design of experiments were used to screen and optimize the important process factors that influence the microbial production of ethanol. A statistically sound regression model was used to establish the mathematical relationship between the process variables and ethanol production. Temperature of 38°C, agitation speed of 200 rpm, pH of 6.3-6.6, and microaerobic condition were the optimum process conditions. Different pretreatment methods to recover glycerol from the crude glycerol and the subsequent fermentation method showed that direct acidification using 85% H3PO4 was the best. The R-glycerol contained 51% pure glycerol and 21% methanol. The wild strain, E. aerogenes ATCC 13048, produced only 12 g/l and 12.8 g/l ethanol from 20 g/l P- and R-glycerol respectively, and could not utilize higher glycerol concentrations. The mutant, E. aerogenes S012, produced ethanol amount and yield of 43 g/l and 1.12 mol/mol-glycerol from P-glycerol, respectively within 96 h. It also produced ethanol amount and yield of 26.8 g/l and 1.07 mol/mol-glycerol, respectively, from R-glycerol within the same duration. In a

  11. Xylitol production by genetically modified industrial strain of Saccharomyces cerevisiae using glycerol as co-substrate.

    Science.gov (United States)

    Kogje, Anushree B; Ghosalkar, Anand

    2017-06-01

    Xylitol is commercially used in chewing gum and dental care products as a low calorie sweetener having medicinal properties. Industrial yeast strain of S. cerevisiae was genetically modified to overexpress an endogenous aldose reductase gene GRE3 and a xylose transporter gene SUT1 for the production of xylitol. The recombinant strain (XP-RTK) carried the expression cassettes of both the genes and the G418 resistance marker cassette KanMX integrated into the genome of S. cerevisiae. Short segments from the 5' and 3' delta regions of the Ty1 retrotransposons were used as homology regions for integration of the cassettes. Xylitol production by the industrial recombinant strain was evaluated using hemicellulosic hydrolysate of the corn cob with glucose as the cosubstrate. The recombinant strain XP-RTK showed significantly higher xylitol productivity (212 mg L -1  h -1 ) over the control strain XP (81 mg L -1  h -1 ). Glucose was successfully replaced by glycerol as a co-substrate for xylitol production by S. cerevisiae. Strain XP-RTK showed the highest xylitol productivity of 318.6 mg L -1  h -1 and titre of 47 g L -1 of xylitol at 12 g L -1 initial DCW using glycerol as cosubstrate. The amount of glycerol consumed per amount of xylitol produced (0.47 mol mol -1 ) was significantly lower than glucose (23.7 mol mol -1 ). Fermentation strategies such as cell recycle and use of the industrial nitrogen sources were demonstrated using hemicellulosic hydrolysate for xylitol production.

  12. Overexpression of the truncated version of ILV2 enhances glycerol production in Saccharomyces cerevisiae.

    Science.gov (United States)

    Murashchenko, Lidiia; Abbas, Charles; Dmytruk, Kostyantyn; Sibirny, Andriy

    2016-08-01

    Acetolactate synthase is a mitochondrial enzyme that catalyses the conversion of two pyruvate molecules to an acetolactate molecule with release of carbon dioxide. The overexpression of the truncated version of the corresponding gene, ILV2, that codes for presumably cytosolic acetolactate synthase in the yeast Saccharomyces cerevisiae, led to a decrease in intracellular pyruvate concentration. This recombinant strain was also characterized by a four-fold increase in glycerol production, with a concomitant 1.8-fold reduction in ethanol production, when compared to that of the wild-type strain under anaerobic conditions in a glucose alcoholic fermentation. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Discovery of the beta-form crystal structure in electrospun nanofibers of bio-based poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] and its implication on properties

    Science.gov (United States)

    Gong, Liang

    Bacterially produced poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] (PHBHx) is a new type of bioplastic which not only inherits the excellent biodegradability and biocompatibility of its parent homopolymer, polyhydroxybutyrate (PHB), but also overcomes PHB’s brittleness and stiffness with the incorporation of 3-hydroxyhexanoate (Hx) comonomer units with medium-chain-length (mcl) side chains. The tough and ductile PHBHx, with a much lower crystallinity and melting temperature, is well-suited for many practical applications. Efforts have been made to broaden the application range of PHBHx by introducing the beta-form crystalline structure, where the molecular chains adopt a planar zig-zag conformation. However, it is extremely difficult to produce this beta-form in PHBHx due to its much lower crystallinity and much more flexible molecular chains. In this study, we report an approach using the technique of electrospinning. The strain-induced metastable β-form crystalline structure was successfully introduced in PHBHx by collecting the macroscopically aligned electrospun PHBHx nanofibers across the air gap on a piece of aluminum foil and on the tapered edge of a high-speed rotary disk. The presence of the β-form crystal structure in electrospun fiber mats was confirmed by wide-angle X-ray diffraction (WAXD) and Fourier transform infrared spectroscopy (FTIR), with molecular orientation of the polymer chains along the fiber axis revealed by polarized FTIR. Selected area electron diffraction (SAED) and AFM-IR were utilized to investigate the morphological and structural details of individual PHBHx nanofibers. The results demonstrated a coexistence of the thermodynamically stable α-form crystalline structure, where molecular chains adopt a left-handed 21 helical conformation, and the β-form in single fibers. The molecular orientation level and the relative amounts of the two crystalline polymorphs were found to be highly dependent on fiber collection methods

  14. Isothermal Vapor-Liquid Equilibrium of Methanol + Glycerol and 1-Propanol + Glycerol

    Directory of Open Access Journals (Sweden)

    Annas Wiguno

    2016-03-01

    Full Text Available Isothermal vapor-liquid equilibrium (VLE data for two binary mixtures of methanol + glycerol and 1-propanol + glycerol were determined at the temperature range from (313.15 to 363.15 K using a simple quasi-static ebulliometer. All systems showed that the vapor pressures increased with increasing alcohols (methanol or 1-propanol concentrations at corresponding system. The Wilson, Non-Random Two-Liquid (NRTL and Universal Quasi-Chemical (UNIQUAC activity coefficient models were used to correlate the experimental data. Both systems showed slightly deviations from the ideal liquid phase behavior.

  15. Enhancement of transdermal delivery of glycerol by micro-needling method combined with sonophoresis

    Science.gov (United States)

    Yoon, Jinhee; Park, Donghee; Son, Taeyoon; Seo, Jongbum; Jung, Byungjo

    2009-02-01

    The light does not penetrate deeply into the skin tissue because of tissue turbidity. Light penetration depth in skin tissue can be increased by using optical clearing agents such as glycerol, glucose and dimethyl sulfoxide(DMSO). The stratum corneum prevents most optical skin clearing agent from diffusing into the tissue. Previous studies demonstrated the optical tissue clearing effect using optical clearing agents and presented several physical methods to improve transdermal delivery of optical clearing agents. In previous study, we introduced a micro-needling method to enhance optical clearing efficacy against skin barrier and suggested quantitative analysis method to evaluate the optical tissue clearing efficacy. In this study, we present a new physical micro-needling method combined with sonophoresis to further enhance the optical tissue clearing efficacy. The optical tissue clearing effect was quantitatively evaluated with a modulation transfer function target placed under ex-vivo porcine skin samples. To improve transdermal delivery of glycerol, 70% glycerol solution as optimal concentration was topically applied. In conclusion, the samples treated with micro-needling method and sonophoresis resulted in noticeable optical tissue clearing effect.

  16. Intercalation compounds of vanadium(5) phosphates with glycerol

    International Nuclear Information System (INIS)

    Yakovleva, T.N.; Vykhodtseva, K.I.; Tarasova, D.V.; Soderzhinova, M.M.

    1997-01-01

    Interaction products of glycerol aqueous solutions with vanadium(5) phosphates were investigated by the methods of ESR, X-ray phase and thermal analyses. It is shown that glycerol molecules enter the interlayer space of VOPO 4 · 2H 2 O lattice with formation of disordered intercalated compounds with glycerol on the basis of partially reduced vanadium phosphate form when using α-VOPO 4 . 16 refs., 4 figs., 1 tab

  17. Glycerol and environmental factors: effects on 1,3-propanediol production and NAD(+) regeneration in Lactobacillus panis PM1.

    Science.gov (United States)

    Kang, T S; Korber, D R; Tanaka, T

    2013-10-01

    This study was conducted to understand the influences of fermentation factors in NADH recycling and mechanisms of 1,3-propanediol (1,3-PDO) production in Lactobacillus panis PM1. We conducted metabolite analyses, qRT-PCR of the glycerol reductive pathway [glycerol dehydratase (DhaB) and 1,3-PDO dehydrogenase (DhaT)] and DhaT activity assays at different pH, temperature and initial glycerol concentrations. The supplementation of 150 mmol l(-1) glycerol caused a shift in NADH flux from ethanol to 1,3-PDO production, whereas 300 mol l(-1) glycerol negatively affected the regeneration of NAD(+) via 1,3-PDO production. This retardation decreased transcription levels and specific activities of DhaT. The decreased DhaT activity eventually caused the shutdown of 1,3-PDO production. Temperature and pH did not significantly affect the specific activity of DhaT, whereas expression of genes for DhaB and DhaT was activated under acidic conditions. Moreover, fresh glucose addition after its depletion could not restart the glycerol reduction, but increased ethanol production. Those environmental factors affect 1,3-PDO production in different ways through changing the expression level of enzymes and shifting the NAD(+) regeneration pathways. Our findings elucidated a key element to optimize 1,3-PDO production by Lact. panis PM1, which potentially improves 1,3-PDO manufacturing efficiencies. © 2013 The Society for Applied Microbiology.

  18. Rebound phenomenon complicating cerebral dehydration with glycerol. Case report.

    Science.gov (United States)

    Guisado, R; Tourtellotte, W W; Arieff, A I; Tomiyasu, U; Mishra, S K; Schotz, M C

    1975-02-01

    A patient with glioblastoma multiforme of the brain was treated with both intravenous and oral glycerol as well as intravenous mannitol in an attempt to reduce increased intracranial pressure. After an initial lowering of the cerebrospinal fluid (CSF) pressure to near normal values during continuous glycerol administration, a secondary rise in CSF pressure above the initial level occurred despite a persistent elevation of plasma osmolality (315 mOsm/kg) and glycerol level (30 mmole/l). Similarly, 4 hours after the administration of a single oral dose of glycerol, CSF pressure increased to levels higher (700 mm H2O) than the original baseline (400 mm H2O).

  19. Apposite of pig skin preserved in glycerol

    International Nuclear Information System (INIS)

    Reyes F, M.L.; Gonzalez V, C.; Salinas A, M.

    2007-01-01

    In the Radio sterilized Tissue Bank (BTR) of the ININ apposite of pig skin are processed and preserved to low temperature (-80 C), which are sterilized by irradiation and transported to the hospitals in dry ice to avoid its unfreezing. With the purpose of making more simple the manipulation of the apposite it was carried out this work that consisted on developing the processing of the pig skin using glycerol like preservation medium, since this way the irradiation, the storage and transport of the apposite is carried out at refrigeration temperature, that makes its manage more simple. (Author)

  20. The quantification of gluconeogenesis in healthy men by (2)H2O and [2-(13)C]glycerol yields different results: rates of gluconeogenesis in healthy men measured with (2)H2O are higher than those measured with [2-(13)C]glycerol

    NARCIS (Netherlands)

    Ackermans, M. T.; Pereira Arias, A. M.; Bisschop, P. H.; Endert, E.; Sauerwein, H. P.; Romijn, J. A.

    2001-01-01

    The quantification of gluconeogenesis (GNG) by (2)H2O and [2-(13)C]glycerol and the mass isotopomer dilution analysis of glucose does not involve assumptions regarding the enrichment of the oxaloacetate precursor pool. To compare these two methods we measured GNG in six healthy postabsorptive males

  1. Glucose allostasis

    DEFF Research Database (Denmark)

    Stumvoll, Michael; Tataranni, P Antonio; Stefan, Norbert

    2003-01-01

    In many organisms, normoglycemia is achieved by a tight coupling of nutrient-stimulated insulin secretion in the pancreatic beta-cell (acute insulin response [AIR]) and the metabolic action of insulin to stimulate glucose disposal (insulin action [M]). It is widely accepted that in healthy...... individuals with normal glucose tolerance, normoglycemia can always be maintained by compensatorily increasing AIR in response to decreasing M (and vice versa). This has been mathematically described by the hyperbolic relationship between AIR and M and referred to as glucose homeostasis, with glucose...... concentration assumed to remain constant along the hyperbola. Conceivably, glucose is one of the signals stimulating AIR in response to decreasing M. Hypothetically, as with any normally functioning feed-forward system, AIR should not fully compensate for worsening M, since this would remove the stimulus...

  2. Effects of glycerol on enzymatic hydrolysis and ethanol production using sugarcane bagasse pretreated by acidified glycerol solution.

    Science.gov (United States)

    Zhang, Zhanying; Wong, Heng H; Albertson, Peter L; Harrison, Mark D; Doherty, William O S; O'Hara, Ian M

    2015-09-01

    In this study, for the first time the effects of glycerol on enzymatic hydrolysis and ethanol fermentation were investigated. Enzymatic hydrolysis was inhibited slightly with 2.0 wt% glycerol, leading to reduction in glucan digestibility from 84.9% without glycerol to 82.9% (72 h). With 5.0 wt% and 10.0 wt% glycerol, glucan digestibility was reduced by 4.5% and 11.0%, respectively. However, glycerol did not irreversibly inhibit cellulase enzymes. Ethanol fermentation was not affected by glycerol up to 5.0 wt%, but was inhibited slightly at 10.0 wt% glycerol, resulting in reduction in ethanol yield from 86.0% in the absence of glycerol to 83.7% (20 h). Based on the results of laboratory and pilot-scale experiments, it was estimated that 0.142 kg ethanol can be produced from 1.0 kg dry bagasse (a glucan content of 38.0%) after pretreatment with acidified glycerol solution. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. The effect of hepatectomy on glucose homeostasis in pig and in man

    DEFF Research Database (Denmark)

    Lauritsen, Torsten Leif Bunk; Grunnet, Niels; Rasmussen, Allan

    2002-01-01

    , blood glucose decreased with a halflife of about 26 min and blood lactate increased. Kidney gluconeogenesis was 0.116+/-0.016 mmol min(-1). Fifty percent of kidney glucose output could be accounted for by lactate- and glycerol uptake. CONCLUSIONS: The results show that in humans extra hepatic...... gluconeogenesis is sufficient to maintain normal blood glucose in the anhepatic phase of orthotopic liver transplantation, while in the pig this was not the case....

  4. Renoprotective effect of low-molecular-weight sulfated polysaccharide from the seaweed Laminaria japonica on glycerol-induced acute kidney injury in rats.

    Science.gov (United States)

    Li, Xinpeng; Wang, Jing; Zhang, Hong; Zhang, Quanbin

    2017-02-01

    We investigated the renal protective effect of low-molecular-weight sulfated polysaccharide (LMWSP) fractions extracted from Laminaria japonica on glycerol-induced acute kidney injury (AKI) in rats. Glycerol treatment significantly increased serum creatinine (SCr) and blood urea nitrogen (BUN) levels. Intraperitoneal injection of LMWSP fractions markedly decreased SCr and BUN levels and reduced renal swelling. The fraction of 1.0M NaCl displayed the best renal protective effect of all fractions in attenuating AKI and maintaining blood glucose. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Poly(3-hydroxybutyrate) and Eudragit E microparticles: a release system to enhance the aqueous solubility of felodipine and simvastatin;Microparticulas de poli(3-hidroxibutirato) e Eudragit E como sistema de liberacao para melhorar a solubilidade aquosa do felodipino e da sinvastatina

    Energy Technology Data Exchange (ETDEWEB)

    Bazzo, Giovana C.; Pezzini, Bianca R.; Zetola, Melissa; Wagner, Theodoro M.; Caetano, Daniela B.; Boch, Maura; Schmucker, Iara C.; Schucko, Sacha K., E-mail: gbazzo@uol.com.b [Universidade da Regiao de Joinville (UNIVILLE), SC (Brazil). Dept. de Farmacia

    2009-07-01

    Poor water-soluble drugs are a problem for the development of oral solid dosage forms, since it has great potential for low bioavailability. Thus, release systems that promote the increase of aqueous solubility of these drugs are advantageous. This study aimed to evaluate the feasibility of incorporation of felodipine and simvastatin in polymeric microparticles, to improve the aqueous solubility of the drugs. Microparticles of poly(3-hydroxybutyrate) [PHB] and Eudragit E was prepared by emulsion - solvent evaporation technique and characterized as to morphology and encapsulation efficiency of the drugs. Particles with spherical shapes and high levels of drug encapsulated were obtained. There was a significant increase in aqueous solubility of felodipine and simvastatin after its incorporation into the polymeric microparticles. X-ray diffraction analysis showed the conversion of both drugs to amorphous form, which may have contributed to increased the solubility. (author)

  6. Produção de poli(3-hidroxibutirato por Cupriavidus Necator em meio hidrolisado de amido de arroz com suplementação de óleo de soja em diferentes temperaturas Production of poly(3-hydroxybutyrate by Cupriavidus Necator in hydrolyzed rice starch medium with soybean oil supplementation at different temperatures

    Directory of Open Access Journals (Sweden)

    Francieli Dalcanton

    2010-01-01

    Full Text Available Poly (3-hydroxybutyrate (P(3HB is a biopolymer, completely biodegradable, which has similar properties to fuel-based polymers. However to make it economically competitive it is necessary the study of cheap sources of substrate. The influence of hydrolyzed rice starch supplemented with soybean oil at different temperatures (30, 35 and 40 °C was studied in the production of P(3HB by C. necator. The percentage of P(3HB produced in the cultures at 30, 35 °C was 30, 39% and 35, 43% without and with supplementation of oil, respectively. The culture at 40 °C showed no production phase due to a possible oxygen limitation. These results demonstrate that hydrolyzed rice starch supplemented with soybean oil increases the yield of P(3HB and temperature of 35 ºC is the most favorable for biopolymer production.

  7. Changes in the microbial community during the acclimation stages of the methane fermentation for the treatment of glycerol

    International Nuclear Information System (INIS)

    Dinh, Nga Thi; Hatta, Kohei; Kwon, Sang Hagk; Rollon, Analiza P.; Nakasaki, Kiyohiko

    2014-01-01

    Granular sludge from a full-scale methane reactor treating brewery wastewater was used as a seed for the treatment of glycerol in a laboratory-scale repeated-batch methane reactor, and the change in the microbial community during the acclimation stages was examined. Two types of substrate solutions, a glucose, sodium acetate, and lactic acid mixture, as well as glycerol, were prepared and fed by mixing the two solutions to increase the ratio, in a stepwise manner, of glycerol from 0% to 100%, while keeping a loading of COD at 2.5 kg m −3  d −1 throughout the fermentation process. Vigorous methane gas production, approximately 580 dm 3  m −3  d −1 , was observed during the acclimation stages. Microbial analysis revealed that both bacterial and archaeal communities changed significantly; bacteria (genus Trichococcus and family Syntrophomonadaceae) became dominant rapidly after the start of acclimation, and archaea belonging to the hydrogenotrophic methanogens (genera Methanobacterium and Methanospirillum), increased gradually with the progress of acclimation. - Highlights: • Acclimation stages to the methane fermentation of glycerol were examined. • Vigorous methane gas production, approximately 580 dm 3  m −3  d −1 , was observed. • Both bacteria and archaea, changed significantly during the acclimation stages. • Bacteria belonging to genus Trichococcus and Syntrophomonadaceae became dominant. • Archaea belonging to the hydrogenotrophic methanogens increased gradually

  8. The role of glycerol-3-phosphate dehydrogenase 1 in the progression of fatty liver after acute ethanol administration in mice

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Tomoki, E-mail: s13220@u-shizuoka-ken.ac.jp [Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526 (Japan); Morita, Akihito, E-mail: moritaa@u-shizuoka-ken.ac.jp [Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526 (Japan); Mori, Nobuko, E-mail: morin@b.s.osakafu-u.ac.jp [Department of Biological Science, Graduate School of Science, Osaka Prefecture University, 1-2 Gakuen-cho, Naka-ku, Sakai 599-8570 (Japan); Miura, Shinji, E-mail: miura@u-shizuoka-ken.ac.jp [Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, 52-1 Yada, Suruga-ku, Shizuoka 422-8526 (Japan)

    2014-02-21

    Highlights: • Ethanol administration increased GPD1 mRNA expression. • Ethanol administration increased glucose incorporation into TG glycerol moieties. • No increase in hepatic TG levels was observed in ethanol-injected GPD1 null mice. • We propose that GPD1 is required for ethanol-induced TG accumulation in the liver. - Abstract: Acute ethanol consumption leads to the accumulation of triglycerides (TGs) in hepatocytes. The increase in lipogenesis and reduction of fatty acid oxidation are implicated as the mechanisms underlying ethanol-induced hepatic TG accumulation. Although glycerol-3-phosphate (Gro3P), formed by glycerol kinase (GYK) or glycerol-3-phosphate dehydrogenase 1 (GPD1), is also required for TG synthesis, the roles of GYK and GPD1 have been the subject of some debate. In this study, we examine (1) the expression of genes involved in Gro3P production in the liver of C57BL/6J mice in the context of hepatic TG accumulation after acute ethanol intake, and (2) the role of GPD1 in the progression of ethanol-induced fatty liver using GPD1 null mice. As a result, in C57BL/6J mice, ethanol-induced hepatic TG accumulation began within 2 h and was 1.7-fold greater than that observed in the control group after 6 h. The up-regulation of GPD1 began 2 h after administering ethanol, and significantly increased 6 h later with the concomitant escalation in the glycolytic gene expression. The incorporation of {sup 14}C-labelled glucose into TG glycerol moieties increased during the same period. On the other hand, in GPD1 null mice carrying normal GYK activity, no significant increase in hepatic TG level was observed after acute ethanol intake. In conclusion, GPD1 and glycolytic gene expression is up-regulated by ethanol, and GPD1-mediated incorporation of glucose into TG glycerol moieties together with increased lipogenesis, is suggested to play an important role in ethanol-induced hepatic TG accumulation.

  9. Microbial community engineering for biopolymer production from glycerol

    NARCIS (Netherlands)

    Moralejo-Gárate, H.; Mar'atusalihat, E.; Kleerebezem, R.; Van Loosdrecht, M.C.M.

    2011-01-01

    In this work, the potential of using microbial community engineering for production of polyhydroxyalkanoates (PHA) from glycerol was explored. Crude glycerol is a by-product of the biofuel (biodiesel and bioethanol) industry and potentially a good substrate for bioplastic production. A PHA-producing

  10. The Acrylation of Glycerol: a Precursor to Functionalized Lipids

    Science.gov (United States)

    Didecanoylacryloylglycerol was synthesized from decanoic and acrylic acids and glycerol using K2O as catalyst. This reaction was carried out in hexane in a closed stainless steel reactor at 200°C for 5h. The reactants were added in a 1:3:4 glycerol:decanoic acid:acrylic acid molar ratio. The resu...

  11. Slow rheological mode in glycerol and glycerol–water mixtures

    DEFF Research Database (Denmark)

    Jensen, Mikkel Hartmann; Gainaru, Catalin; Alba-Simionesco, Christiane

    2018-01-01

    Glycerol–water mixtures were studied at molar concentrations ranging from xgly = 1 (neat glycerol) to xgly = 0.3 using shear mechanical spectroscopy. We observed a low frequency mode in neat glycerol, similar to what has been reported for monohydroxy alcohols. This mode has no dielectric...

  12. Glycerol reforming in supercritical water : a short review

    NARCIS (Netherlands)

    Markocic, Elena; Kramberger, Boris; van Bennekom, Joost G.; Heeres, Hero Jan; Vos, John; Knez, Zeljko; Markočič, Elena; Knez, Željko

    Due to the rise in global biodiesel production, the amount of crude glycerol, the main byproduct, has increased steadily. Identification of high value added outlets for crude glycerol has been explored in detail to increase the overall economics of the biodiesel process. Examples are the use of

  13. Development of ethanol production from cooking oil glycerol waste ...

    African Journals Online (AJOL)

    Tuoyo Aghomotsegin

    2016-10-12

    Oct 12, 2016 ... toiletries, plastics, leather, and textile. Glycerol, a major by-product in biodiesel manufacturing process, ..... Purification of crud glycerol from waste cooking oil based biodiesel production by orthogonal test method. China Pet. Process. Petrochem. Technol. 15:48-53. Volker FW, Steffen NL, Tobias MM (2011).

  14. On the amino acid esters of phosphatidyl glycerol from bacteria

    NARCIS (Netherlands)

    Houtsmuller, U.M.T.; Deenen, L.L.M. van

    1965-01-01

    1. 1. The phospholipids of Staphylococcus aureus were fractionated on silicic acid columns. The major compounds all appeared to be polyglycerol lipids. Diphosphatidyl glycerol and phosphatidyl glycerol were identified by comparison with the synthetic phospholipids. 2. 2. An amino acid derivative

  15. Effect of crude glycerol from South African biodiesel production on ...

    African Journals Online (AJOL)

    OlivierR

    2013-06-13

    Jun 13, 2013 ... growth, carcass characteristics and pork quality of pigs. E.K. Chiloane. 2 ... A study was carried out to evaluate the effects of dietary inclusion of crude glycerol as a partial replacement of ... that crude glycerol can be included up to 100 g/kg in grower pig diets without any negative effects on pig performance.

  16. Studi Awal Proses Pembuatan Glycerol Tribenzoat Dari Gliserol Dan Asam Benzoat Dengan Menggunakan Katalis Asam Klorida

    OpenAIRE

    Abdurrakhman, A; Rifianto, Yanuar; Widayat, W

    2013-01-01

    Glycerol esterification process is one method that is widely in the conversion of glycerol. The product of conversion glycerol is environmentally friendly and renewable because it is not derived from petroleum. The products of the conversion of glycerol is commonly used in the food industry, cosmetics industry, polymer industry and can also be used as an additive for biodiesel which is also the compound before the glycerol formed. This study aims to examine the reaction of glycerol and benzoi...

  17. Bioconversion of crude glycerol feedstocks into ethanol by Pachysolen tannophilus

    DEFF Research Database (Denmark)

    Liu, Xiaoying; Jensen, Peter Ruhdal; Workman, Mhairi

    2012-01-01

    Glycerol, the by-product of biodiesel production, is considered as a waste by biodiesel producers. This study demonstrated the potential of utilising the glycerol surplus through conversion to ethanol by the yeast Pachysolen tannophilus (CBS4044). This study demonstrates a robust bioprocess which...... glycerol, corresponding to 56% of the theoretical yield. A staged batch process achieved 28.1 g/L ethanol, the maximum achieved so far for conversion of glycerol to ethanol in a microbial bioprocess. The fermentation physiology has been investigated as a means to designing a competitive bioethanol...... was not sensitive to the batch variability in crude glycerol dependent on raw materials used for biodiesel production. The oxygen transfer rate (OTR) was a key factor for ethanol production, with lower OTR having a positive effect on ethanol production. The highest ethanol production was 17.5 g/L on 5% (v/v) crude...

  18. Conserved family of glycerol kinase loci in Drosophila melanogaster

    Science.gov (United States)

    Martinez Agosto, Julian A.; McCabe, Edward R.B.

    2009-01-01

    Glycerol kinase (GK) is an enzyme that catalyzes the formation of glycerol 3-phosphate from ATP and glycerol, the rate-limiting step in glycerol utilization. We analyzed the genome of the model organism Drosophila melanogaster and identified five GK orthologs, including two loci with sequence homology to the mammalian Xp21 GK protein. Using a combination of sequence analysis and evolutionary comparisons of orthologs between species, we characterized functional domains in the protein required for GK activity. Our findings include additional conserved domains that suggest novel nuclear and mitochondrial functions for glycerol kinase in apoptosis and transcriptional regulation. Investigation of GK function in Drosophila will inform us about the role of this enzyme in development and will provide us with a tool to examine genetic modifiers of human metabolic disorders. PMID:16545593

  19. Branched glycerol dialkyl glycerol tetraethers and crenarchaeol record post-glacial sea level rise in the Kara Sea (Arctic Ocean)

    NARCIS (Netherlands)

    De Jonge, C.; Stadnitskaia, A.N.; Cherkashov, Georgy; Sinninghe Damsté, J.S.

    This study evaluates the glycerol dialkyl glycerol tetraether (GDGT) distribution and provenance in sediments (spanning a minimum of 13.3 ka) from the St. Anna Trough (Northern Kara Sea). The site has experienced extensive fluctuation in the delivery of river-derived organic matter (OM), caused by a

  20. Microemulsion based hybrid biofuels using glycerol monooleate

    International Nuclear Information System (INIS)

    Bora, Plaban; Konwar, Lakhya Jyoti; Deka, Dhanapati

    2016-01-01

    Highlights: • Fuel quality of GMO based MHBFs. • Effect of externally added monoglyceride surfactant (GMO) on fuel characteristics of MHBF. • Structural and dynamic behaviors of GMO based MHBFs. • Can offer strong candidature for future biofuel industry. - Abstract: The present investigation aims to highlighten the effect of monoglyceride surfactant (GMO) on structure and dynamic behavior and other fuel characteristics of microemulsion based hybrid biofuels (MHBFs). Fuel quality of MHBFs formulated using purified GMO (>90%), which was prepared by esterification of glycerol, was investigated in the study. Phase behaviors, droplet size distribution, number of droplets present in the system, average droplet size and average length of surface active agents were studied as a part of structural investigations of the GMO based MHBFs. Diffusion coefficient, energy barrier to droplet coalescence and rate of coalescence of droplets were also investigated for the formulated MHBFs. The number of droplets, length of surface active agent and the diffusion co-efficient were in the ranges of 1.87 × 10 21 –5.66 × 10 21 /m 3 , 0.92–1.07 nm and 1.00 × 10 −11 –1.79 × 10 −11 m 2 /s, respectively. The rate of droplet coalescence was obtained in the range 2.77 × 10 −4 –8.78 × 10 −4 times the collision factor. MHBFs incorporating the glycerol derived bio-based nonionic surfactant GMO exhibited viscosity of 4.12 mm 2 /s (at 40 °C), gross calorific value (GCV) of 39.17 MJ/kg and pour point of −7 °C.

  1. Development Of An Efficient Glycerol Utilizing Saccharomyces Cerevisiae Strain Via Adaptive Laboratory Evolution

    DEFF Research Database (Denmark)

    Strucko, Tomas; Zirngibl, Katharina; Tharwat Tolba Mohamed, Elsayed

    2015-01-01

    catabolism in yeast. The knowledge acquired in this study may be further applied for rational S. cerevisiae strain improvement for using glycerol as a carbon source in industrial biotechnology processes. This work is a part of the DeYeastLibrary consortium financed by ERA-IB DeYeastLibrary - Designer yeast......With increasing interest in biosustainable technologies, the need for converting available non-saccharide carbon sources most efficiently is emerging. Highly abundant crude glycerol, a major waste residue in biodiesel production, has attracted attention as a cheap carbon source for microbial...... fermentation processes. The most commonly known microbial cell factory, the yeast Saccharomyces cerevisiae, has been extensively applied for the production of a wide range of scientifically and industrially relevant products using saccharides (mainly glucose) as carbon source. However, it was shown...

  2. Effects of glycerol administration on experimental brain edema.

    Science.gov (United States)

    Guisado, R; Arieff, A I; Massry, S G

    1976-01-01

    The effects of glycerol on brain water and solute distribution in cerebral edema are not well known. In brail edema induced in dogs by focal freezing, tissue underlying the necrotic lesion had an elevated water content but the remainder of the brain was unaltered. Administration of glycerol to maintain plasma glycerol at about 35 mM dehydrated normal white matter, but water and solute contents of the edematous white matter were not changed. During the initial 3 hours of glycerol infusion, CSF pressure fell, but when the infusion was continued for 6 hours or more, a gradual rise in CSF pressure was observed. In three animals, the final CSF pressure was higher than preinfusion values. At this time, brain water content was significantly less than normal, but both CSF osmolality and glycerol concentration were higher than plasma. The data show that glycerol infusion can decrease intracranial volume towards normal by dehydration of normal, but not damaged, brain tissue. The rebound rise in CSF pressure observed during the continuous administration of glycerol cannot be explained by rehydration of brain tissue but may be related to alterations in CSF dynamics.

  3. Reduced hepatic aquaporin-9 and glycerol permeability are related to insulin resistance in non-alcoholic fatty liver disease.

    Science.gov (United States)

    Rodríguez, A; Gena, P; Méndez-Giménez, L; Rosito, A; Valentí, V; Rotellar, F; Sola, I; Moncada, R; Silva, C; Svelto, M; Salvador, J; Calamita, G; Frühbeck, G

    2014-09-01

    Glycerol represents an important metabolite for the control of lipid accumulation and hepatic gluconeogenesis. We investigated whether hepatic expression and functionality of aquaporin-9 (AQP9), a channel mediating glycerol influx into hepatocytes, is impaired in non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) in the context of insulin resistance. Liver biopsies were obtained from 66 morbid obese patients undergoing bariatric surgery (66% women, mean body mass index (BMI) 46.1±1.0 kg m(-2)) with available liver echography and pathology analysis of the biopsies in this cross-sectional study. Subjects were classified according to normoglycemia (NG), impaired glucose tolerance (IGT) or type 2 diabetes (T2D). Hepatic expression of AQP9 was analyzed by real-time PCR, western blotting and immunohistochemistry, while glycerol permeability (P(gly)) was measured by stopped-flow light scattering. AQP9 was the most abundantly (PAQP3>AQP7>AQP10). Obese patients with T2D showed increased plasma glycerol as well as lower P(gly) and hepatic AQP9 expression. The prevalence of NAFLD and NASH in T2D patients was 100 and 65%, respectively. Interestingly, AQP9 expression was decreased in patients with NAFLD and NASH as compared with those without hepatosteatosis, in direct relation to the degree of steatosis and lobular inflammation, being further reduced in insulin-resistant individuals. The association of AQP9 with insulin sensitivity was independent of BMI and age. Consistent with these data, fasting insulin and C-reactive protein contributed independently to 33.1% of the hepatic AQP9 mRNA expression variance after controlling for the effects of age and BMI. AQP9 downregulation together with the subsequent reduction in hepatic glycerol permeability in insulin-resistant states emerges as a compensatory mechanism whereby the liver counteracts further triacylglycerol accumulation within its parenchyma as well as reduces hepatic gluconeogenesis in patients

  4. Effects of supplementing glycerol and soybean oil in drinking water on feed and water intake, energy balance, and production performance of periparturient dairy cows.

    Science.gov (United States)

    Osborne, V R; Odongo, N E; Cant, J P; Swanson, K C; McBride, B W

    2009-02-01

    The objective of this study was to determine the effects of supplementing glycerol and soybean oil in drinking water on feed and water intake, calculated energy balance, and production performance of periparturient dairy cows. Ninety multiparous Holstein dairy cows were randomly assigned to 1 of 3 treatments: 1) no nutrients supplemented in the drinking water (control); 2) 20 g/L of glycerin supplemented in the drinking water (glycerol); and 3) 10 g/L of soybean oil supplemented in the drinking water (SBO). The trial lasted from 7 d prepartum to 7 d postpartum. Cows were offered a close-up and milking cow TMR for ad libitum intake, pre- and postpartum, respectively. The dry matter intake of cows supplemented with glycerol and SBO was lower than for the control cows throughout the experimental period but not different from each other. Water intake for the control cows was greater than the average for the glycerol and SBO cows prepartum, and greater than for SBO cows but similar to that of glycerol cows postpartum. Glycerol cows consumed more water than SBO cows. There were no differences in energy intake and energy balance of the cows pre- and postpartum. Serum triacylglycerol concentration for glycerol cows was lower than for the control and SBO cows prepartum and was lower than for the SBO cows postpartum. There were no differences in the serum nonesterified fatty acids and glucose concentrations throughout the experiment. There were no differences in the serum beta-hydroxybutyrate (BHBA) concentrations at parturition, but serum BHBA concentration of the glycerol cows was greater than for control and SBO cows during the prepartum period. However, during the postpartum period, serum BHBA concentrations of the control cows were greater than for glycerol and SBO cows. There were no differences in calf birth weights or milk yield and composition. Although the glucogenic property of glycerol supplemented in the drinking water at 20 g/L may not have been sufficient to

  5. Metabolic fate of glucose and candidate signaling and excess-fuel detoxification pathways in pancreatic β-cells.

    Science.gov (United States)

    Mugabo, Yves; Zhao, Shangang; Lamontagne, Julien; Al-Mass, Anfal; Peyot, Marie-Line; Corkey, Barbara E; Joly, Erik; Madiraju, S R Murthy; Prentki, Marc

    2017-05-05

    Glucose metabolism promotes insulin secretion in β-cells via metabolic coupling factors that are incompletely defined. Moreover, chronically elevated glucose causes β-cell dysfunction, but little is known about how cells handle excess fuels to avoid toxicity. Here we sought to determine which among the candidate pathways and coupling factors best correlates with glucose-stimulated insulin secretion (GSIS), define the fate of glucose in the β-cell, and identify pathways possibly involved in excess-fuel detoxification. We exposed isolated rat islets for 1 h to increasing glucose concentrations and measured various pathways and metabolites. Glucose oxidation, oxygen consumption, and ATP production correlated well with GSIS and saturated at 16 mm glucose. However, glucose utilization, glycerol release, triglyceride and glycogen contents, free fatty acid (FFA) content and release, and cholesterol and cholesterol esters increased linearly up to 25 mm glucose. Besides being oxidized, glucose was mainly metabolized via glycerol production and release and lipid synthesis (particularly FFA, triglycerides, and cholesterol), whereas glycogen production was comparatively low. Using targeted metabolomics in INS-1(832/13) cells, we found that several metabolites correlated well with GSIS, in particular some Krebs cycle intermediates, malonyl-CoA, and lower ADP levels. Glucose dose-dependently increased the dihydroxyacetone phosphate/glycerol 3-phosphate ratio in INS-1(832/13) cells, indicating a more oxidized state of NAD in the cytosol upon glucose stimulation. Overall, the data support a role for accelerated oxidative mitochondrial metabolism, anaplerosis, and malonyl-CoA/lipid signaling in β-cell metabolic signaling and suggest that a decrease in ADP levels is important in GSIS. The results also suggest that excess-fuel detoxification pathways in β-cells possibly comprise glycerol and FFA formation and release extracellularly and the diversion of glucose carbons to

  6. Vanadium-Catalyzed Deoxydehydration of Glycerol Without an External Reductant

    DEFF Research Database (Denmark)

    Petersen, Allan Robertson; Nielsen, Lasse Bo; Dethlefsen, Johannes Rytter

    2018-01-01

    A vanadium‐catalysed deoxydehydration (DODH) of neat glycerol has been developed. Cheap and readily available ammonium metavanadate (NH4VO3) affords higher yields of allyl alcohol than the well‐established catalyst methyltrioxorhenium. A study in which deuterium‐labelled glycerol was used was und...... was undertaken to further elucidate the dual role of glycerol as both an oxidant and reductant. This study led to the proposal of a metal‐catalysed DODH mechanism for the production of allyl alcohol and a deeper understanding of the formation of the byproducts acrolein and propanal....

  7. Slow rheological mode in glycerol and glycerol–water mixtures

    DEFF Research Database (Denmark)

    Jensen, Mikkel Hartmann; Gainaru, Catalin; Alba-Simionesco, Christiane

    2018-01-01

    counterpart and disappears with increased water concentration. We propose that the hydrogen-bonded network formed between glycerol molecules is responsible for the observed slow mode and that water acts as a plasticizer for the overall dynamics and as a lubricant softening the hydrogen-bonding contribution......Glycerol–water mixtures were studied at molar concentrations ranging from xgly = 1 (neat glycerol) to xgly = 0.3 using shear mechanical spectroscopy. We observed a low frequency mode in neat glycerol, similar to what has been reported for monohydroxy alcohols. This mode has no dielectric...

  8. Glucose allostasis

    DEFF Research Database (Denmark)

    Stumvoll, Michael; Tataranni, P Antonio; Stefan, Norbert

    2003-01-01

    (insulin resistance), we propose to use the term "glucose allostasis." Allostasis (stability through change) ensures the continued homeostatic response (stability through staying the same) to acute stress at some cumulative costs to the system. With increasing severity and over time, the allostatic load......In many organisms, normoglycemia is achieved by a tight coupling of nutrient-stimulated insulin secretion in the pancreatic beta-cell (acute insulin response [AIR]) and the metabolic action of insulin to stimulate glucose disposal (insulin action [M]). It is widely accepted that in healthy...

  9. Evidence that glucose is the major transferred metabolite in dinoflagellate–cnidarian symbiosis

    Science.gov (United States)

    Burriesci, Matthew S.; Raab, Theodore K.; Pringle, John R.

    2012-01-01

    SUMMARY Reef-building corals and many other cnidarians are symbiotic with dinoflagellates of the genus Symbiodinium. It has long been known that the endosymbiotic algae transfer much of their photosynthetically fixed carbon to the host and that this can provide much of the host's total energy. However, it has remained unclear which metabolite(s) are directly translocated from the algae into the host tissue. We reexamined this question in the small sea anemone Aiptasia using labeling of intact animals in the light with 13C-bicarbonate, rapid homogenization and separation of animal and algal fractions, and analysis of metabolite labeling by gas chromatography-mass spectrometry. We found labeled glucose in the animal fraction within 2 min of exposure to 13C-bicarbonate, whereas no significant labeling of other compounds was observed within the first 10 min. Although considerable previous evidence has suggested that glycerol might be a major translocated metabolite, we saw no significant labeling of glycerol within the first hour, and incubation of intact animals with 13C-labeled glycerol did not result in a rapid production of 13C-glucose. In contrast, when Symbiodinium cells freshly isolated from host tissue were exposed to light and 13C-bicarbonate in the presence of host homogenate, labeled glycerol, but not glucose, was detected in the medium. We also observed early production of labeled glucose, but not glycerol, in three coral species. Taken together, the results suggest that glucose is the major translocated metabolite in dinoflagellate–cnidarian symbiosis and that the release of glycerol from isolated algae may be part of a stress response. PMID:22956249

  10. Glycerol metabolism in the methylotrophic yeast Hansenula polymorpha : phosphorylation as the initial step

    NARCIS (Netherlands)

    Koning, W. de; Harder, W.; Dijkhuizen, L.

    1987-01-01

    In Hansenula polymorpha glycerol is metabolized via glycerol kinase and NAD(P)-independent glycerol-3-phosphate (G3P) dehydrogenase, enzymes which hitherto were reported to be absent in this methylotrophic yeast. Activity of glycerol kinase was readily detectable when cell-free extracts were

  11. Recent Advances in Glycerol Polymers: Chemistry and Biomedical Applications

    Science.gov (United States)

    Zhang, Heng

    2015-01-01

    Glycerol polymers are attracting increased attention due to the diversity of polymer compositions and architectures available. This article provides a brief chronological review on the current status of these polymers along with representative examples of their use for biomedical applications. First, we describe the underlying chemistry of glycerol, which provides access to a range of monomers for subsequent polymerizations. We then review the various synthetic methodologies to prepare glycerol-based polymers including polyethers, polycarbonates, polyesters, and so forth. Next, we describe several biomedical applications where glycerol polymers are being investigated including carriers for drug delivery, sealants or coatings for tissue repair, and agents possessing antibacterial activity. Fourth, we describe the growing market opportunity for the use of polymers in medicine. Finally we conclude and summarize the findings, as well as discuss potential opportunities for continued research efforts. PMID:25308354

  12. Supercritical water reformation of crude glycerol solution for hydrogen production.

    Science.gov (United States)

    2009-12-01

    Glycerol, also known as glycerin, is a less desirable byproduct formed in the production of biodiesel via the transesterification otriglycerides and presents a nontrivial issue in terms of developing other beneficial end uses. With an inflated glycer...

  13. Recent advances in glycerol polymers: chemistry and biomedical applications.

    Science.gov (United States)

    Zhang, Heng; Grinstaff, Mark W

    2014-11-01

    Glycerol polymers are attracting increased attention due to the diversity of polymer compositions and architectures available. This article provides a brief chronological review on the current status of these polymers along with representative examples of their use for biomedical applications. First, the underlying chemistry of glycerol that provides access to a range of monomers for subsequent polymerizations is described. Then, the various synthetic methodologies to prepare glycerol-based polymers including polyethers, polycarbonates, polyesters, and so forth are reviewed. Next, several biomedical applications where glycerol polymers are being investigated including carriers for drug delivery, sealants or coatings for tissue repair, and agents possessing antibacterial activity are described. Fourth, the growing market opportunity for the use of polymers in medicine is described. Finally, the findings are concluded and summarized, as well as the potential opportunities for continued research efforts are discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Glycerol extracting dealcoholization for the biodiesel separation process.

    Science.gov (United States)

    Ye, Jianchu; Sha, Yong; Zhang, Yun; Yuan, Yunlong; Wu, Housheng

    2011-04-01

    By means of utilizing sunflower oil and Jatropha oil as raw oil respectively, the biodiesel transesterification production and the multi-stage extracting separation were carried out experimentally. Results indicate that dealcoholized crude glycerol can be utilized as the extracting agent to achieve effective separation of methanol from the methyl ester phase, and the glycerol content in the dealcoholized methyl esters is as low as 0.02 wt.%. For the biodiesel separation process utilizing glycerol extracting dealcoholization, its technical and equipment information were acquired through the rigorous process simulation in contrast to the traditional biodiesel distillation separation process, and results show that its energy consumption decrease about 35% in contrast to that of the distillation separation process. The glycerol extracting dealcoholization has sufficient feasibility and superiority for the biodiesel separation process. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Quantitative evaluation of yeast's requirement for glycerol formation in very high ethanol performance fed-batch process

    Directory of Open Access Journals (Sweden)

    Nevoigt Elke

    2010-05-01

    Full Text Available Abstract Background Glycerol is the major by-product accounting for up to 5% of the carbon in Saccharomyces cerevisiae ethanolic fermentation. Decreasing glycerol formation may redirect part of the carbon toward ethanol production. However, abolishment of glycerol formation strongly affects yeast's robustness towards different types of stress occurring in an industrial process. In order to assess whether glycerol production can be reduced to a certain extent without jeopardising growth and stress tolerance, the yeast's capacity to synthesize glycerol was adjusted by fine-tuning the activity of the rate-controlling enzyme glycerol 3-phosphate dehydrogenase (GPDH. Two engineered strains whose specific GPDH activity was significantly reduced by two different degrees were comprehensively characterized in a previously developed Very High Ethanol Performance (VHEP fed-batch process. Results The prototrophic strain CEN.PK113-7D was chosen for decreasing glycerol formation capacity. The fine-tuned reduction of specific GPDH activity was achieved by replacing the native GPD1 promoter in the yeast genome by previously generated well-characterized TEF promoter mutant versions in a gpd2Δ background. Two TEF promoter mutant versions were selected for this study, resulting in a residual GPDH activity of 55 and 6%, respectively. The corresponding strains were referred to here as TEFmut7 and TEFmut2. The genetic modifications were accompanied to a strong reduction in glycerol yield on glucose; the level of reduction compared to the wild-type was 61% in TEFmut7 and 88% in TEFmut2. The overall ethanol production yield on glucose was improved from 0.43 g g-1 in the wild type to 0.44 g g-1 measured in TEFmut7 and 0.45 g g-1 in TEFmut2. Although maximal growth rate in the engineered strains was reduced by 20 and 30%, for TEFmut7 and TEFmut2 respectively, strains' ethanol stress robustness was hardly affected; i.e. values for final ethanol concentration (117 ± 4 g

  16. Effects of glucose availability on expression of the key genes involved in synthesis of milk fat, lactose and glucose metabolism in bovine mammary epithelial cells.

    Directory of Open Access Journals (Sweden)

    Hongyun Liu

    Full Text Available As the main precursor for lactose synthesis, large amounts of glucose are required by lactating dairy cows. Milk yield greatly depends on mammary lactose synthesis due to its osmoregulatory property for mammary uptake of water. Thus, glucose availability to the mammary gland could be a potential regulator of milk production. In the present study, the effect of glucose availability on expression of the key genes involved in synthesis of milk fat, lactose and glucose metabolism in vitro was investigated. Bovine mammary epithelial cells (BMEC were treated for 12 h with various concentrations of glucose (2.5, 5, 10 or 20 mmol/L. The higher concentrations of glucose (10-20 mmol/L did not affect the mRNA expression of acetyl-CoA carboxylase, diacyl glycerol acyl transferase, glycerol-3 phosphate acyl transferase and α-lactalbumin, whereas fatty acid synthase, sterol regulatory element binding protein-1 and beta-1, 4-galactosyl transferase mRNA expression increased at 10 mmol/L and then decreased at 20 mmol/L. The content of lactose synthase increased with increasing concentration of glucose, with addition of highest value at 20 mmol/L of glucose. Moreover, the increased glucose concentration stimulated the activities of pyruvate kinase and glucose-6-phosphate dehydrogenase, and elevated the energy status of the BMEC. Therefore, it was deduced that after increasing glucose availability, the extra absorbed glucose was partitioned to entering the synthesis of milk fat and lactose by the regulation of the mRNA expression of key genes, promoting glucose metabolism by glycolysis and pentose phosphate pathway as well as energy status. These results indicated that the sufficient availability of glucose in BMEC may promote glucose metabolism, and affect the synthesis of milk composition.

  17. Evaluation of propylene glycol and glycerol infusions as treatments for ketosis in dairy cows.

    Science.gov (United States)

    Piantoni, P; Allen, M S

    2015-08-01

    To evaluate propylene glycol (PG) and glycerol (G) as potential treatments for ketosis, we conducted 2 experiments lasting 4 d each in which cows received one bolus infusion per day. Blood was collected before infusion, over 240min postinfusion, as well as 24 h postinfusion. Experiment 1 used 6 ruminally cannulated cows (26±7 d in milk) randomly assigned to 300-mL infusions of PG or G (both ≥99.5% pure) in a crossover design experiment with 2 periods. Within each period, cows were assigned randomly to infusion site sequence: abomasum (A)-cranial reticulorumen (R) or the reverse, R-A. Glucose precursors were infused into the R to simulate drenching and the A to prevent metabolism by ruminal microbes. Glycerol infused in the A increased plasma glucose concentration the most (15.8mg/dL), followed by PG infused in the R (12.6mg/dL), PG infused in the A (9.11mg/dL), and G infused in the R (7.3mg/dL). Infusion of PG into the R increased plasma insulin and insulin area under the curve (AUC) the most compared with all other treatments (7.88 vs. 2.13μIU/mL and 321 vs. 31.9min×μIU/mL, respectively). Overall, PG decreased plasma BHBA concentration after infusion (-6.46 vs. -4.55mg/dL) and increased BHBA AUC (-1,055 vs. -558min ×mg/dL) compared with G. Plasma NEFA responses were not different among treatments. Experiment 2 used 8 ruminally cannulated cows (22±5 d in milk) randomly assigned to treatment sequence in a Latin square design experiment balanced for carryover effects. Treatments were 300mL of PG, 300mL of G, 600mL of G (2G), and 300mL of PG + 300mL of G (GPG), all infused into the R. Treatment contrasts compared PG with each treatment containing glycerol (G, 2G, and GPG). Propylene glycol increased plasma glucose (14.0 vs. 5.35mg/dL) and insulin (7.59 vs. 1.11μIU/mL) concentrations compared with G, but only tended to increase glucose and insulin concentrations compared with 2G. Propylene glycol increased AUC for glucose (1,444 vs. 94.3mg/dL) and insulin (326

  18. Hydrogen generation from glycerol in batch fermentation process

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, K.; Waligorska, M.; Wojtowski, M.; Laniecki, M. [Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznan (Poland)

    2009-05-15

    The influence of concentration of glycerol, inoculum and total nitrogen on hydrogen generation, in batch dark fermentation process in the presence of digested sludge (at 37 C and at initial pH = 6) was studied. Changes in substrate and products concentrations were modeled with modified Gompertz equations (correlation coefficient R{sup 2} = 0.9015). The 1,3-propandiol, butyric acid, acetic acid, lactic acid and ethanol were found as the main liquid metabolites. Maximal substrate yield for hydrogen was 0.41 mol H{sub 2}/mol glycerol and was obtained for medium containing 10 g/l of glycerol with the lowest amount of inoculum - 1.16 g volatile suspended solid (VSS)/l. Increase of glycerol concentration from 5 to 30 g/l resulted in much better hydrogen generation, namely from 0.345 to 0.715 l H{sub 2}/l. Further increase of glycerol concentration did not cause any changes. The H{sub 2}:CO{sub 2} ratio in biogas in system with the highest substrate yield was always 1. The initial concentration of glycerol does not influence the rate of hydrogen generation. The increase of initial concentration of inoculum from 1.2 to 11.6 g VSS/l results in the decrease of specific hydrogen yield. Nitrogen concentration in medium does not influence the hydrogen production. (author)

  19. Baker's yeast catalyzed asymmetric reduction of methyl acetoacetate in glycerol containing systems

    Directory of Open Access Journals (Sweden)

    Adi Wolfson

    2008-09-01

    Full Text Available The asymmetric hydrogenation of methyl acetoacetate was successfully performed with baker's yeast in pure glycerol and mixtures of glycerol and water. Though yeast viability was very low after exposure to glycerol, the enzymatic activity in pure glycerol was preserved for some days. In addition, a mixture of glycerol and water combined the advantageous of each individual solvent and resulted in high catalytic performance and efficient product extraction yield

  20. Processes and systems for the production of propylene glycol from glycerol

    Energy Technology Data Exchange (ETDEWEB)

    Frye, John G; Oberg, Aaron A; Zacher, Alan H

    2015-01-20

    Processes and systems for converting glycerol to propylene glycol are disclosed. The glycerol feed is diluted with propylene glycol as the primary solvent, rather than water which is typically used. The diluted glycerol feed is sent to a reactor where the glycerol is converted to propylene glycol (as well as other byproducts) in the presence of a catalyst. The propylene glycol-containing product from the reactor is recycled as a solvent for the glycerol feed.

  1. Impact of Glycerol as Carbon Source onto Specific Sugar and Inducer Uptake Rates and Inclusion Body Productivity in E. coli BL21(DE3

    Directory of Open Access Journals (Sweden)

    Julian Kopp

    2017-12-01

    Full Text Available The Gram-negative bacterium E. coli is the host of choice for a multitude of used recombinant proteins. Generally, cultivation is easy, media are cheap, and a high product titer can be obtained. However, harsh induction procedures using isopropyl β-d-1 thiogalactopyranoside as inducer are often referred to cause stress reactions, leading to a phenomenon known as “metabolic” or “product burden”. These high expressions of recombinant proteins mainly result in decreased growth rates and cell lysis at elevated induction times. Therefore, approaches tend to use “soft” or “tunable” induction with lactose and reduce the stress level of the production host. The usage of glucose as energy source in combination with lactose as induction reagent causes catabolite repression effects on lactose uptake kinetics and as a consequence reduced product titer. Glycerol—as an alternative carbon source—is already known to have positive impact on product formation when coupled with glucose and lactose in auto-induction systems, and has been referred to show no signs of repression when cultivated with lactose concomitantly. In recent research activities, the impact of different products on the lactose uptake using glucose as carbon source was highlighted, and a mechanistic model for glucose-lactose induction systems showed correlations between specific substrate uptake rate for glucose or glycerol (qs,C and the maximum specific lactose uptake rate (qs,lac,max. In this study, we investigated the mechanistic of glycerol uptake when using the inducer lactose. We were able to show that a product-producing strain has significantly higher inducer uptake rates when being compared to a non-producer strain. Additionally, it was shown that glycerol has beneficial effects on viability of cells and on productivity of the recombinant protein compared to glucose.

  2. Combinations of glycerol percent, glycerol equilibration time, and thawing rate upon freezability of bull spermatozoa in plastic straws.

    Science.gov (United States)

    Wiggin, H B; Almquist, J O

    1975-03-01

    Twelve ejaculates were used in a central composite experiment to test 15 combinations of glycerol (7, 9, 11, 13, or 15%), glycerol equilibration times (1, 2, 4, 8, or 16 h) and thawing rates (water at 35 C for 15 s, 50 C for 13 s, 65 C for 11 s, 80 C for 9 s, or 95 C for 7 s). Semen was diluted in heated skim milk-glycerol, packaged in .3-ml. Continental U.S. straws and frozen in liquid nitrogen vapor. Based on post-thaw progressive sperm motility after storage at -196 C for 9 to 11 days, estimated optima from multiple regression were 10.7% for glycerol, 2.0 h for glycerol equilibration time, and 76 C for thawing bath temperature. Only the linear effect for each variable was significant. Much faster thawing rates and shorter glycerol equilibration times than those for freezing bull spermatozoa in glass ampules should be used for maximum post-thaw sperm motility in straws.

  3. Activation of glycerol metabolic pathway by evolutionary engineering of Rhizopus oryzae to strengthen the fumaric acid biosynthesis from crude glycerol.

    Science.gov (United States)

    Huang, Di; Wang, Ru; Du, Wenjie; Wang, Guanyi; Xia, Menglei

    2015-11-01

    Rhizopus oryzae is strictly inhibited by biodiesel-based by-product crude glycerol, which results in low fumaric acid production. In this study, evolutionary engineering was employed to activate the glycerol utilization pathway for fumaric acid production. An evolved strain G80 was selected, which could tolerate and utilize high concentrations of crude glycerol to produce 14.9g/L fumaric acid with a yield of 0.248g/g glycerol. Key enzymes activity analysis revealed that the evolved strain displayed a significant upregulation in glycerol dissimilation, pyruvate consumption and reductive tricarboxylic acid pathways, compared with the parent strain. Subsequently, intracellular metabolic profiling analysis showed that amino acid biosynthesis, tricarboxylic acid cycle, fatty acid and stress response metabolites accounted for metabolic difference between two strains. Moreover, a glycerol fed-batch strategy was optimized to obtain the highest fumaric acid production of 25.5g/L, significantly increased by 20.9-fold than that of the parent strain of 1.2g/L. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Triacylglycerol secretion in rats: validation of a tracer method employing radioactive glycerol

    International Nuclear Information System (INIS)

    Bird, M.; Williams, M.A.; Baker, N.

    1984-01-01

    A two-compartment model was developed to analyze the temporal changes in plasma triacylglycerol (TG)-specific radioactivity after injection of [2- 3 H]glycerol into rats. The analysis, which yielded fractional rate constants of TG secretion, was tested in rats fed diets either adequate or deficient in essential fatty acids (EFA) and containing either glucose, fructose or sucrose as the dietary carbohydrate. The method of analysis appeared valid, first, because of a close agreement between experimental and computer-fitted TG-specific radioactivity curves, and second, because the fractional rate constants obtained were quite similar to fractional rate constants determined previously by the Triton WR-1339 technique in rats maintained on identical diets. The results show that EFA deficiency increased the fractional rate constant of TG secretion 1.7-, 1.8- and 3.3-fold and the rate of TG secretion 1.8-, 1.6- and 1.4-fold when the dietary carbohydrate was glucose, sucrose and fructose, respectively, in comparison with control rats fed diets supplying these same carbohydrates but adequate in EFA. In the latter groups, the rates of plasma TG secretion were in the range of 0.14-0.17 mg/min per 100 g body weight, and the rate of secretion in the fructose-fed rats was only 20% higher than in the glucose-fed rats

  5. Engineering the productivity of recombinant Escherichia coli for limonene formation from glycerol in minimal media.

    Science.gov (United States)

    Willrodt, Christian; David, Christian; Cornelissen, Sjef; Bühler, Bruno; Julsing, Mattijs K; Schmid, Andreas

    2014-08-01

    The efficiency and productivity of cellular biocatalysts play a key role in the industrial synthesis of fine and bulk chemicals. This study focuses on optimizing the synthesis of (S)-limonene from glycerol and glucose as carbon sources using recombinant Escherichia coli. The cyclic monoterpene limonene is extensively used in the fragrance, food, and cosmetic industries. Recently, limonene also gained interest as alternative jet fuel of biological origin. Key parameters that limit the (S)-limonene yield, related to genetics, physiology, and reaction engineering, were identified. The growth-dependent production of (S)-limonene was shown for the first time in minimal media. E. coli BL21 (DE3) was chosen as the preferred host strain, as it showed low acetate formation, fast growth, and high productivity. A two-liquid phase fed-batch fermentation with glucose as the sole carbon and energy source resulted in the formation of 700 mg L(org) (-1) (S)-limonene. Specific activities of 75 mU g(cdw) (-1) were reached, but decreased relatively quickly. The use of glycerol as a carbon source resulted in a prolonged growth and production phase (specific activities of ≥50 mU g(cdw) (-1) ) leading to a final (S)-limonene concentration of 2,700 mg L(org) (-1) . Although geranyl diphosphate (GPP) synthase had a low solubility, its availability appeared not to limit (S)-limonene formation in vivo under the conditions investigated. GPP rerouting towards endogenous farnesyl diphosphate (FPP) formation also did not limit (S)-limonene production. The two-liquid phase fed-batch setup led to the highest monoterpene concentration obtained with a recombinant microbial biocatalyst to date. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Progressive alterations in lipid and glucose metabolism during short-term fasting in young adult men

    NARCIS (Netherlands)

    Klein, S.; Sakurai, Y.; Romijn, J. A.; Carroll, R. M.

    1993-01-01

    Stable isotope tracers and indirect calorimetry were used to evaluate the progressive alterations in lipid and glucose metabolism after 12, 18, 24, 30, 42, 54, and 72 h of fasting in six healthy male volunteers. The rates of appearance (Ra) of glycerol and palmitic acid in plasma doubled from 2.08

  7. High Protein Diet Maintains Glucose Production During Exercise-Induced Energy Deficit: A Controlled Trial

    Science.gov (United States)

    2011-04-28

    watching TV , playing video games, reading) on days 1, 5, and 8. Isotope-Infusion Protocol Endogenous rate of glucose production and the...responsiveness in normal and obese human subjects. Am J Physiol 1987, 252:E189-E196. 24. Bortz WM, Paul P, Haff AC, Holmes WL: Glycerol turnover

  8. Neuroscience of glucose homeostasis

    NARCIS (Netherlands)

    La Fleur, S E; Fliers, E; Kalsbeek, A

    2014-01-01

    Plasma glucose concentrations are homeostatically regulated and maintained within strict boundaries. Several mechanisms are in place to increase glucose output when glucose levels in the circulation drop as a result of glucose utilization, or to decrease glucose output and increase tissue glucose

  9. Effect of shortening the prefreezing equilibration time with glycerol on the quality of chamois (Rupicapra pyrenaica), ibex (Capra pyrenaica), mouflon (Ovis musimon) and aoudad (Ammotragus lervia) ejaculates.

    Science.gov (United States)

    Pradiee, J; O'Brien, E; Esteso, M C; Castaño, C; Toledano-Díaz, A; Lopez-Sebastián, A; Marcos-Beltrán, J L; Vega, R S; Guillamón, F G; Martínez-Nevado, E; Guerra, R; Santiago-Moreno, J

    2016-08-01

    The present study reports the effect of shortening the prefreezing equilibration time with glycerol on the quality of frozen-thawed ejaculated sperm from four Mediterranean mountain ungulates: Cantabrian chamois (Rupicapra pyrenaica), Iberian ibex (Capra pyrenaica), mouflon (Ovis musimon) and aoudad (Ammotragus lervia). Ejaculated sperm from these species were divided into two aliquots. One was diluted with either a Tris-citric acid-glucose based medium (TCG-glycerol; for chamois and ibex sperm) or a Tris-TES-glucose-based medium (TTG-glycerol; for mouflon and aoudad sperm), and maintained at 5°C for 3h prior to freezing. The other aliquot was diluted with either TCG (chamois and ibex sperm) or TTG (mouflon and aoudad sperm) and maintained at 5°C for 1h before adding glycerol (final concentration 5%). After a 15min equilibration period in the presence of glycerol, the samples were frozen. For the ibex, there was enhanced (P<0.05) sperm viability and acrosome integrity after the 3h as compared with the 15min equilibration time. For the chamois, subjective sperm motility and cell membrane functional integrity were less (P<0.05) following 15min of equilibration. In the mouflon, progressive sperm motility and acrosome integrity was less (P<0.05) when the equilibration time was reduced to 15min. For the aoudad, the majority of sperm variables measured were more desirable after the 3h equilibration time. The freezing-thawing processes reduced the sperm head size in all the species studied; however, the equilibration time further affected the frozen-thawed sperm head variables in a species-dependent fashion. While the equilibration time for chamois sperm might be shortened, this appears not to be the case for all ungulates. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Characterization of Carrageenan Edible films Plasticized with Glycerol

    Directory of Open Access Journals (Sweden)

    Arham Rusli

    2017-08-01

    Full Text Available Concentration of base materials and plasticizers used in the formulation of edible film was believed to affect physical characteristics of the film. The objectives of this study were to evaluate the effects of base material (carrageenan and plasticiser (glycerol concentrations on the characteristics of edible films produced and to determine the best concentrations of these two components based on the physical characteristics of the films. The experiment was conducted using a completely randomized factorial design with triplicated. The treatments applied were the concentrations of carrageenan (1%, 2%, and 3% (w/v and glycerol (5%, 10%, and 15% (w/w. The results showed that carrageenan and glycerol concentrations used in the formulation of edible film affect the edible film characteristics. Film thickness and moisture content were significantly influenced by carrageenan and glycerol concentrations, while film elongation was only affected by carrageenan concentration. The best physical characteristic of the edible films was obtained when carrageenan and glycerol concentrations were 3% and 10% respectively.

  11. Digestible energy of crude glycerol for pacu and silver catfish

    Directory of Open Access Journals (Sweden)

    Rafael Ernesto Balen

    2014-01-01

    Full Text Available The increase in global biodiesel production is originating a glycerol surplus, which has no defined destination. An alternative to overcome this problem is its use as energy source in animal feeding. In Brazil, Pacu (Piaractus mesopotamicus is one of the most farmed native fish species, whereas Silver catfish (Rhamdia quelen is suitable for production in subtropical region. Considering little knowledge about crude glycerol utilization in feeds for Neotropical fish species, it was evaluated the apparent digestibility coefficients (ADCs for energy of crude glycerol for P. mesopotamicus and R. quelen. The digestibility and digestible energy content of crude glycerol can be considered excellent even when compared to energy of common ingredients such as maize and wheat, presenting 0.97 and 0.89 of energy ADCs, and 15.2 and 13.95MJ kg-1 of digestible energy for Pacu and Silver catfish, respectively. In conclusion, crude glycerol is an energetic ingredient with good potential in Brazilian native fish diets.

  12. An experimental and kinetic modeling study of glycerol pyrolysis

    International Nuclear Information System (INIS)

    Fantozzi, F.; Frassoldati, A.; Bartocci, P.; Cinti, G.; Quagliarini, F.; Bidini, G.; Ranzi, E.M.

    2016-01-01

    Highlights: • Glycerol pyrolysis can produce about 44–48%v hydrogen at 750–800 °C. • A simplified 452 reactions kinetic model of glycerol pyrolysis has been developed. • The model has good agreement with experimental data. • Non condensable gas yields can reach 70%. - Abstract: Pyrolysis of glycerol, a by-product of the biodiesel industry, is an important potential source of hydrogen. The obtained high calorific value gas can be used either as a fuel for combined heat and power (CHP) generation or as a transportation fuel (for example hydrogen to be used in fuel cells). Optimal process conditions can improve glycerol pyrolysis by increasing gas yield and hydrogen concentration. A detailed kinetic mechanism of glycerol pyrolysis, which involves 137 species and more than 4500 reactions, was drastically simplified and reduced to a new skeletal kinetic scheme of 44 species, involved in 452 reactions. An experimental campaign with a batch pyrolysis reactor was properly designed to further validate the original and the skeletal mechanisms. The comparisons between model predictions and experimental data strongly suggest the presence of a catalytic process promoting steam reforming of methane. High pyrolysis temperatures (750–800 °C) improve process performances and non-condensable gas yields of 70%w can be achieved. Hydrogen mole fraction in pyrolysis gas is about 44–48%v. The skeletal mechanism developed can be easily used in Computational Fluid Dynamic software, reducing the simulation time.

  13. Crude glycerol as glycogenic precursor in feed; effects on milk coagulation properties and metabolic profiles of dairy cows.

    Science.gov (United States)

    Harzia, Hedi; Kilk, Kalle; Ariko, Tiia; Kass, Marko; Soomets, Ursel; Jõudu, Ivi; Kaart, Tanel; Arney, David; Kärt, Olav; Ots, Meelis

    2013-05-01

    As grain prices rise, the search for alternative glycogenic precursors in animal feed becomes increasingly important, and this study was conducted to determine if the replacement of starch with glycerol, as an alternative glycogenic precursor, affects the milk metabolic profile and milk coagulation ability, and therefore the quality of the milk. Eight primiparous mid-lactation Holstein cows were fed during a replicated 4 × 4 Latin square trial with four different isoenergetic rations: (1) control (T0) fed a total mixed ration (TMR) with barley meal; (2) group T1, decreased barley content, replaced isoenergetically with 1 kg crude glycerol; (3) group T2, the barley meal was replaced with 2 kg of crude glycerol; and (4) group T3 the barley meal was replaced with 3 kg of crude glycerol. Rumen, blood and milk samples were collected at the end of every 21-d treatment period. Rumen samples were analysed for proportion of total volatile fatty acid (VFA), blood samples for insulin and glucose, and milk for metabolites (e.g. citric-acid cycle compounds). The change in glycogenic precursors had a positive effect on rumen VFA proportions; the proportion of propionic acid increased (P Milk protein (P milk protein concentration may have been due to an increase in microbial protein. Regarding the milk metabolic profiles, different signals were positively associated with coagulation ability and change in the diet. Based on this study, changing the glycogenic precursor in animal diet in this way is possible, and may have no immediate deleterious consequences on milk quality or cow health. Indeed, there is evidence for benefits from this substitution.

  14. Effects of addition glycerol co-product of biodiesel in the thermophysical properties of water-glycerol solution applied as secondary coolant

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Pedro Samuel Gomes; Barbosa, Cleiton Rubens Formiga; Fontes, Francisco de Assis Oliveira [Federal University of Rio Grande do Norte, Natal, RN (Brazil). Energy Laboratory. Thermal Systems Studies Group], e-mail: cleiton@ufrnet.br

    2010-07-01

    This paper evaluates the effects of glycerol concentration on thermophysical properties of water-glycerol solution applied as a secondary coolant in refrigeration systems by expansion-indirect. The processing of triglycerides for biodiesel production generates glycerol as co-product and there are concerns of environmental and economic order on the surplus of glycerol. The addition of glycerol in water alters the colligative and thermophysical properties (melting point, mass, specific heat, thermal conductivity and dynamic viscosity). There are studies that prove the feasibility of using glycerol as an additive and this paper has the goal to verify the changes on properties compared with pure water. This comparison was made from data obtained by the software simulation and they analyzed using graphs and tables. It was shown that glycerol increases the density and dynamic viscosity, and reduces the specific heat and thermal conductivity. This behavior of water-glycerol solution is proportional to the mass concentration of glycerol and it is justified because the glycerol has low values of specific heat, thermal conductivity and high viscosity when compared with water. Despite the losses in the thermophysical properties, glycerol shows its potential application, because of the cryoscopic effect and it is a non-toxic substance at low cost. (author)

  15. Towards the sustainable production of acrolein by glycerol dehydration.

    Science.gov (United States)

    Katryniok, Benjamin; Paul, Sébastien; Capron, Mickaël; Dumeignil, Franck

    2009-01-01

    The massive increase in biodiesel production by transesterification of vegatable oils goes hand-in-hand with the availability of a large volume of glycerol, which must be valorized. Glycerol dehydration to acrolein over acid catalysts is one of the most promising ways of valorization, because this compound is an important chemical intermediate used in, for example, the DL-methionine synthesis. In this Minireview, we give a detailed critical view of the state-of-the-art of this dehydration reaction. The processes developed in both the liquid and the gas phases are detailed and the best catalytic results obtained so far are reported as a benchmark for future developments. The advances on the understanding of the reaction mechanism are also discussed and we further focus particularly on the main obstacles for an immediate industrial application of this technology, namely catalyst coking and crude glycerol direct-use issues.

  16. Studies on the dehydration of glycerol over niobium catalysts.

    Science.gov (United States)

    Lee, Young Yi; Moon, Dong Ju; Kim, Jong Ho; Park, Nam Cook; Kim, Young Chul

    2011-08-01

    The dehydration of glycerol over nanosize niobium catalysts was conducted in a stainless steel autoclave reactor. The catalysts were prepared by the calcination of niobium oxalate between 200 and 700 degrees C. Catalysts were characterized by N2 Physisorption, XRD and TPD of ammonia to investigate the effect of the calcination temperature and water on catalytic performance, catalysts' structures and acidity. Acrolein was mainly produced about 51-71% with useful by-products such as acetaldehyde and methanol. Amorphous Nb2O5 catalysts calcined at 200-400 degrees C significantly showed higher conversion of glycerol than the crystallized Nb2O5 catalyst calcined at 500-700 degrees C. Also the conversion of glycerol and selectivity of acrolein was increased with increasing the acidity of catalyst, which can be controlled by calcination temperature.

  17. Ru/FTO: Heterogeneous catalyst for glycerol hydrogenolysis

    Science.gov (United States)

    Samad, Wan Zurina; Isahak, Wan Nor Roslam Wan; Liew, Kin Hong; Nordin, Norazzizi; Yarmo, Mohd Ambar; Yusop, Muhammad Rahimi

    2014-09-01

    An introduction of Fluorine-doped tin oxide (FTO) as new catalyst support with Ru metal had enhanced the conversion and selectivity for glycerol hydrogenolysis. A small cluster of Ru were highly dispersed and intercalated over FTO via simple chemical mixture and reduction method. In comparison with various metal (Pd, Os, Cu), Ru/FTO catalyst showed the highest conversion (100%) and highly selectivity of 1,2-propanediol (94%) in the hydrogenolysis of glycerol. The reaction was optimally conducted at 150 °C, 20 bar of H2 pressure and at 8 hours. Ru/FTO catalyst was ascribed as active catalyst due to the amphoteric sites of FTO and small size of Ru metal. This provides high surface concentration of reduction process that involves the chemical bond dissociation in the glycerol hydrogenolysis.

  18. Crude glycerol combustion: Particulate, acrolein, and other volatile organic emissions

    KAUST Repository

    Steinmetz, Scott

    2013-01-01

    Crude glycerol is an abundant by-product of biodiesel production. As volumes of this potential waste grow, there is increasing interest in developing new value added uses. One possible use, as a boiler fuel for process heating, offers added advantages of energy integration and fossil fuel substitution. However, challenges to the use of crude glycerol as a boiler fuel include its low energy density, high viscosity, and high autoignition temperature. We have previously shown that a refractory-lined, high swirl burner can overcome challenges related to flame ignition and stability. However, critical issues related to ash behavior and the possible formation of acrolein remained. The work presented here indicates that the presence of dissolved catalysts used during the esterification and transesterification processes results in extremely large amounts of inorganic species in the crude glycerol. For the fuels examined here, the result is a submicron fly ash comprised primarily of sodium carbonates, phosphates, and sulfates. These particles report to a well-developed accumulation mode (0.3-0.7 μm diameter), indicating extensive ash vaporization and particle formation via nucleation, condensation, and coagulation. Particle mass emissions were between 2 and 4 g/m3. These results indicate that glycerol containing soluble catalyst is not suitable as a boiler fuel. Fortunately, process improvements are currently addressing this issue. Additionally, acrolein is of concern due to its toxicity, and is known to be formed from the low temperature thermal decomposition of glycerol. Currently, there is no known reliable method for measuring acrolein in sources. Acrolein and emissions of other volatile organic compounds were characterized through the use of a SUMMA canister-based sampling method followed by GC-MS analysis designed for ambient measurements. Results indicate crude glycerol combustion produces relatively small amounts of acrolein (∼15 ppbv) and other volatile organic

  19. Chemical and biological conversion of crude glycerol derived from waste cooking oil to biodiesel.

    Science.gov (United States)

    Chen, Jiaxin; Yan, Song; Zhang, Xiaolei; Tyagi, Rajeshwar Dayal; Surampalli, Rao Y; Valéro, J R

    2018-01-01

    In this study, crude, purified, and pure glycerol were used to cultivate Trichosporon oleaginosus for lipid production which was then used as feedstock of biodiesel production. The purified glycerol was obtained from crude glycerol by removing soap with addition of H 3 PO 4 which converted soap to free fatty acids and then separated from the solution. The results showed that purified glycerol provided similar performance as pure glycerol in lipid accumulation; however, crude glycerol as carbon source had negatively impacted the lipid production of T. oleaginosus. Purified glycerol was later used to determine the optimal glycerol concentration for lipid production. The highest lipid yield 0.19g/g glycerol was obtained at 50g/L purified glycerol in which the biomass concentration and lipid content were 10.75g/L and 47% w/w, respectively. An energy gain of 4150.51MJ could be obtained with 1tonne of the crude glycerol employed for biodiesel production through the process proposed in this study. The biodiesel production cost estimated was 6.32US$/gal. Fatty acid profiles revealed that C16:0 and C18:1 were the major compounds of the biodiesel from the lipid produced by T. oleaginosus cultivated with crude and purified glycerol. The study found that purified glycerol was promising carbon source for biodiesel production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Use of an osmotically sensitive mutant of Propionibacterium freudenreichii subspp. shermanii for the simultaneous productions of organic acids and trehalose from biodiesel waste based crude glycerol.

    Science.gov (United States)

    Ruhal, Rohit; Choudhury, Bijan

    2012-04-01

    Recently suitability of crude glycerol for trehalose and propionic acid productions was reported using Propionibacterium freudenreichii subspp. shermanii and it was concluded that presence of KCl in crude glycerol was the probable reason for higher trehalose accumulation with crude glycerol medium. To further improve trehalose production, an osmotic sensitive mutant of this strain (non-viable in medium with 3% NaCl) with higher trehalose yield was isolated. In mutant, trehalose yields achieved with respect to biomass and substrate consumed (391 mg/g of biomass, 90 mg/g of substrate consumed) were three and four times higher, respectively as compared to parent strain when crude glycerol was used as a carbon source. Other major fermentation products obtained were propionic acid (0.42 g/g of substrate consumed) and lactic acid (0.3g/g of substrate consumed). It was also observed that in mutant higher activity of ADP-glucose pyrophosphorylase was probably responsible for higher trehalose accumulation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Propylene from renewable resources: catalytic conversion of glycerol into propylene.

    Science.gov (United States)

    Yu, Lei; Yuan, Jing; Zhang, Qi; Liu, Yong-Mei; He, He-Yong; Fan, Kang-Nian; Cao, Yong

    2014-03-01

    Propylene, one of the most demanded commodity chemicals, is obtained overwhelmingly from fossil resources. In view of the diminishing fossil resources and the ongoing climate change, the identification of new efficient and alternative routes for the large-scale production of propylene from biorenewable resources has become essential. Herein, a new selective route for the synthesis of propylene from bio-derived glycerol is demonstrated. The route consists of the formation of 1-propanol (a versatile bulk chemical) as intermediate through hydrogenolysis of glycerol at a high selectivity. A subsequent dehydration produces propylene. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Redução da massa molecular e funcionalização do poli(3-hidroxibutirato-co-3-hidroxivalerato (PHBHV via hidrólise ácida e transesterificação com glicóis Reduction of molecular weight and functionalization of poly(3-hydroxybutyrate-co-3-hidroxyvalerate (PHBHV by acid hydrolysis and transesterification with glycols

    Directory of Open Access Journals (Sweden)

    Sérgio R. Montoro

    2011-01-01

    Full Text Available Neste trabalho foi realizado um estudo da redução da massa molecular do poli (3-hidroxibutirato-co-3-hidroxivalerato (PHBHV usando duas metodologias: hidrólise ácida com ácido clorídrico e transesterificação com etilenoglicol e hexilenoglicol. Foram investigados os parâmetros do processo: tempo, temperatura e concentração de catalisadores. Todas as metodologias estudadas geraram biopolímeros com massa molecular reduzida e funcionalizados com grupos hidroxila e carboxila terminais. Foram comparadas as metodologias estudadas, onde foi possível determinar a metodologia mais eficaz na funcionalização do PHBHV. A redução da massa molecular, associada a estratégias de funcionalização, é extremamente útil para promover alterações na taxa de degradação do PHBHV, ampliando assim as suas aplicações como biomateriais.In this work we investigated the reduction in molecular weight of poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBHV with two methods: by acid hydrolysis and transesterification with ethylene and hexyleneglycol. The processing parameters studied were time, temperature and concentration of catalysts. Both methodologies resulted in functionalized biopolymers with hydroxyl and carboxyl end-groups and reduced molecular weight. A comparison of the methodologies allowed us to determine which one was more efficient for the functionalization of PHBHV. The reduction in molecular weight associated with functionalization strategies is extremely useful to induce changes in the degradation rate of materials, thus broadening their applications as biomaterials.

  3. Freeze resistance in rainbow smelt (Osmerus mordax): seasonal pattern of glycerol and antifreeze protein levels and liver enzyme activity associated with glycerol production.

    Science.gov (United States)

    Lewis, Johanne M; Ewart, K Vanya; Driedzic, William R

    2004-01-01

    Rainbow smelt (Osmerus mordax) inhabit inshore waters along the North American Atlantic coast. During the winter, these waters are frequently ice covered and can reach temperatures as low as -1.9 degrees C. To prevent freezing, smelt accumulate high levels of glycerol, which lower the freezing point via colligative means, and antifreeze proteins (AFP). The up-regulation of the antifreeze response (both glycerol and AFP) occurs in early fall, when water temperatures are 5 degrees -6 degrees C. The accumulation of glycerol appears to be the main mechanism of freeze resistance in smelt because it contributes more to the lowering of the body's freezing point than the activity of the AFP (0.5 degrees C vs. 0.25 degrees C for glycerol and AFP, respectively) at a water temperature of -1.5 degrees C. Moreover, AFP in smelt appears to be a safeguard mechanism to prevent freezing when glycerol levels are low. Significant increases in activities of the liver enzymes glycerol 3-phosphate dehydrogenase (GPDH), alanine aminotransferase (AlaAT), and phosphoenolpyruvate carboxykinase (PEPCK) during the initiation of glycerol production and significant correlations between enzyme activities and plasma glycerol levels suggest that these enzymes are closely associated with the synthesis and maintenance of elevated glycerol levels for use as an antifreeze. These findings add further support to the concept that carbon for glycerol is derived from amino acids.

  4. Glucose and cardiovascular risk

    NARCIS (Netherlands)

    Fuchs, M.; Hoekstra, J. B. L.; Mudde, A. H.

    2002-01-01

    The American Diabetes Association and the World Health Organisation have recently redefined the spectrum of abnormal glucose tolerance. The criteria for diabetes mellitus were sharpened and impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) were classified as intermediate stages

  5. Synthesis of High-Molecular-Weight Multifunctional Glycerol Polyhydroxyurethanes PHUs

    Directory of Open Access Journals (Sweden)

    Bassam Nohra

    2016-09-01

    Full Text Available Glycerol carbonate acrylate is a 5-membered cyclic carbonate synthesized from glycerol that is used as a chemical coupling agent and has proven highly suitable for use in the synthesis of multifunctional polyhydroxyurethanes (PHUs. The multifunctionality of the structure of PHUs is determined by the density of the carbon-amine groups generated by the Aza-Michael reaction and that of the urethane groups and adjacent primary and secondary hydroxyl groups generated by aminolysis. Glycerol carbonate acrylate is polymerized with polyfunctional mono-, di-, tri, and tetra-amines, by type-AB polyaddition, either in bulk or in solution, through stepwise or one-pot reaction strategies in the absence of added catalysts. These approaches result in the generation of linear, interchain, and crosslinked structures, through the polyaddition of linear and branched amines to the ethylene and cyclic carbonate sites of glycerol carbonate acrylate. The resulting collection of organic molecules gives rise to polyethylene amino ester PHUs with a high molar mass, exceeding 20,000 g·mol−1, with uniform dispersity.

  6. Production of glycerol from palm kernel oil | Antia | Nigerian Journal ...

    African Journals Online (AJOL)

    Glycerol production using Palm Kernel Oil (PKO) as a potential raw material was investigated. PKO was optimally hydrolyzed at 268 °C and 500psi (34 atm) pressure using only water. A 96.85 percent maximum yield of the extent of hydrolysis at 61.86 percent water and 38.14 percent oil was achieved The percentage Df ...

  7. Genetic determinants for enhanced glycerol growth of Saccharomyces cerevisiae.

    Science.gov (United States)

    Swinnen, Steve; Ho, Ping-Wei; Klein, Mathias; Nevoigt, Elke

    2016-07-01

    The yeast Saccharomyces cerevisiae generally shows a low natural capability to utilize glycerol as the sole source of carbon, particularly when synthetic medium is used and complex supplements are omitted. Nevertheless, wild type isolates have been identified that show a moderate growth under these conditions. In the current study we made use of intraspecies diversity to identify targets suitable for reverse metabolic engineering of the non-growing laboratory strain CEN.PK113-1A. A genome-wide genetic mapping experiment using pooled-segregant whole-genome sequence analysis was conducted, and one major and several minor genetic loci were identified responsible for the superior glycerol growth phenotype of the previously selected S. cerevisiae strain CBS 6412-13A. Downscaling of the major locus by fine-mapping and reciprocal hemizygosity analysis allowed the parallel identification of two superior alleles (UBR2CBS 6412-13A and SSK1CBS 6412-13A). These alleles together with the previously identified GUT1CBS 6412-13A allele were used to replace the corresponding alleles in the strain CEN.PK113-1A. In this way, glycerol growth could be established reaching a maximum specific growth rate of 0.08h(-1). Further improvement to a maximum specific growth rate of 0.11h(-1) could be achieved by heterologous expression of the glycerol facilitator FPS1 from Cyberlindnera jadinii. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  8. EFFECT OF GLYCEROL SEPARATION ON PALM OIL TRANSESTERIFICATION

    Directory of Open Access Journals (Sweden)

    Budy Rahmat

    2012-12-01

    Full Text Available This research was aimed to study the effect of glycerol separation on palm oil transesterification. Objectives of this study were to suppress the use of excess methanol and shorten the processing time. This research consisted of: design-build reactor, the effect of the glycerol separation on the transesterification reaction, characterization of biodiesel, and mass balance analysis. The reactor was designed by integrating circulate stirrer pump, static mixer, and sprayer that will bring out the intense reaction in the outer tank reactor. The experiment in this research was the treatment of decreasing the quantity of methanol to 5:1 molar ratio and reducing of processing time to 20 min, which was arranged in a completely randomized factorial design. The result showed that, (i the stirring system was effectively worked outside the reactor tank, and in its reactor tank occurred glycerol separation during the process; (ii the rate of glycerol during the process followed the inverse regression equation of Ŷ = 66.44-351.17 X-1; (iii the decrease in the level of methanol to 5:1 molar ratio and the reduction of processing time to 20 min in this engineering did not influence the biodiesel yield and quality that met the SNI 04-7182-2006 standard.

  9. Development of ethanol production from cooking oil glycerol waste ...

    African Journals Online (AJOL)

    Bacterial strains, capable of producing ethanol by using cooking oil glycerol waste (derived from biodiesel production) as sole C-source were screened from soil samples. Based on 16S rRNA sequence, the selected strain was identified as Enterobacter aerogenes G2WG. The sequence was submitted to GenBank and the ...

  10. Crude glycerol combustion: particulate, acrolein, and other volatile organic emissions

    Science.gov (United States)

    Crude glycerol is an abundant by-product of biodiesel production. As volumes of this potential waste grow, there is increasing interest in developing new value added uses. One possible use, as a boiler fuel for process heating, offers added advantages of energy integration and ...

  11. Investigation of glycerol polymerization in the clinker grinding process

    NARCIS (Netherlands)

    Parvulescu, A.N.; Rossi, M.; Della Pina, C.; Ciriminna, R.; Pagliaro, M.

    2011-01-01

    Concrete production is a large scale process that involves high energy consumption. In order to increase the sustainability of this process, the reduction of energy input is necessary. Bio-glycerol was demonstrated to be a highly efficient renewable-based additive in the grinding process for

  12. Novel inhibitors of mitochondrial sn-glycerol 3-phosphate dehydrogenase.

    Directory of Open Access Journals (Sweden)

    Adam L Orr

    Full Text Available Mitochondrial sn-glycerol 3-phosphate dehydrogenase (mGPDH is a ubiquinone-linked enzyme in the mitochondrial inner membrane best characterized as part of the glycerol phosphate shuttle that transfers reducing equivalents from cytosolic NADH into the mitochondrial electron transport chain. Despite the widespread expression of mGPDH and the availability of mGPDH-null mice, the physiological role of this enzyme remains poorly defined in many tissues, likely because of compensatory pathways for cytosolic regeneration of NAD⁺ and mechanisms for glycerol phosphate metabolism. Here we describe a novel class of cell-permeant small-molecule inhibitors of mGPDH (iGP discovered through small-molecule screening. Structure-activity analysis identified a core benzimidazole-phenyl-succinamide structure as being essential to inhibition of mGPDH while modifications to the benzimidazole ring system modulated both potency and off-target effects. Live-cell imaging provided evidence that iGPs penetrate cellular membranes. Two compounds (iGP-1 and iGP-5 were characterized further to determine potency and selectivity and found to be mixed inhibitors with IC₅₀ and K(i values between ∼1-15 µM. These novel mGPDH inhibitors are unique tools to investigate the role of glycerol 3-phosphate metabolism in both isolated and intact systems.

  13. Dark fermentative bioconversion of glycerol to hydrogen by Bacillus thuringiensis.

    Science.gov (United States)

    Kumar, Prasun; Sharma, Rishi; Ray, Subhasree; Mehariya, Sanjeet; Patel, Sanjay K S; Lee, Jung-Kul; Kalia, Vipin C

    2015-04-01

    Biodiesel manufacturing units discharge effluents rich in glycerol. The need is to convert crude glycerol (CG) into useful products such as hydrogen (H2). Under batch culture, Bacillusthuringiensis EGU45 adapted on pure glycerol (PG, 2% v/v) resulted in an H2 yield of 0.646 mol/mol glycerol consumed on minimal media (250 mL) supplemented with 1% ammonium nitrate at 37°C over 4 days. Here, H2 constituted 67% of the total biogas. Under continuous culture, at 2 days of hydraulic retention time, B. thuringiensis immobilized on ligno-cellulosic materials (banana leaves - BL, 10% v/v) resulted in a H2 yield of 0.386 mol/mol PG consumed. On CG, the maximal H2 yield of 0.393 mol/mol feed consumed was recorded. In brief, B. thuringiensis could transform CG, on limited resources - minimal medium with sodium nitrate, by immobilizing them on cheap and easily available biowaste, which makes it a suitable candidate for H2 production on a large scale. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Fluorescence anisotropy of acridinedione dyes in glycerol: Prolate ...

    Indian Academy of Sciences (India)

    Time-dependent reorientations of resorcinol-based acridinidione (ADR) dyes in glycerol were studied using steady-state and time-resolved fluorescence studies. The difference between fluorescence anisotropy decays recorded at 460 nm when exciting at 250 nm and those obtained when exciting at 394 nm are reported.

  15. Isolated and contiguous glycerol kinase gene disorders: a review

    NARCIS (Netherlands)

    Sjarif, D. R.; Ploos van Amstel, J. K.; Duran, M.; Beemer, F. A.; Poll-The, B. T.

    2000-01-01

    Glycerol kinase deficiency (GKD) is an X-linked recessive disorder. There are two types. an isolated form and a complex form. We review the clinical, biochemical and molecular genetic features of GKD. The clinical and biochemical phenotype of isolated GKD may vary from a life-threatening childhood

  16. Methylene blue adsorption from glycerol solution onto the acicular ...

    African Journals Online (AJOL)

    The mechanism of methylene blue adsorption onto the surface of synthetic acicular habit of α-goethite from glycerol solution has been studied through batch experiment at 25, 30 and 35 0C in a glass cell of minimal dead volume. To describe the adsorption results, an attempt was made to fit the data to the Langmuir, ...

  17. Production of 1,3-propanediol from glycerol by engineered ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-19

    propanediol ... 1,3-Propanediol (1,3-PD) is one of the most interested ..... containing 40 g/L glycerol. The values showed were averaged from two independent triplicate experiments with means less than 5%. 1 2 M 3 4. kDa. 116.0.

  18. Elastic neutron scattering study of proton dynamics in glycerol

    Science.gov (United States)

    Cornicchi, Elena; Cinelli, Stefania; Natali, Francesca; Onori, Giuseppe; Paciaroni, Alessandro

    2004-07-01

    A recent neutron scattering investigation on lysozyme embedded in glycerol-water mixtures has shown that solvent dynamics is crucial in determining the dynamical properties of the biomolecule itself (Biophys. J. 83 (2002) 1157). To better understand the role played by solvent, we have performed an elastic incoherent neutron scattering (INS) experiment as a function of the temperature on pure glycerol. To directly compare the dynamics of the solvated protein and that of the pure solvent, we settled the same experimental conditions and applied the same data analysis procedure as in Paciaroni et al. (Biophys. J. 83 (2002) 1157). By using a double-well model and taking into account for the global molecular diffusion, we exploited the measured intensity to estimate the mean square displacements (MSD) of glycerol hydrogen atoms. We found that the total MSD deviate from the low-temperature vibrational harmonic trend at approximately T=235K, consistent with the value of the critical temperature reported in literature (Phys. Rev. E 55 (1997) 3183). The present investigation suggests that the internal dynamics of glycerol molecules, i.e. the vibrations and reorientations of hydrogen atoms relative to the molecular centre of mass (c.o.m.), can be put in relationship with the protein dynamics.

  19. Elastic neutron scattering study of proton dynamics in glycerol

    International Nuclear Information System (INIS)

    Cornicchi, Elena; Cinelli, Stefania; Natali, Francesca; Onori, Giuseppe; Paciaroni, Alessandro

    2004-01-01

    A recent neutron scattering investigation on lysozyme embedded in glycerol-water mixtures has shown that solvent dynamics is crucial in determining the dynamical properties of the biomolecule itself (Biophys. J. 83 (2002) 1157). To better understand the role played by solvent, we have performed an elastic incoherent neutron scattering (INS) experiment as a function of the temperature on pure glycerol. To directly compare the dynamics of the solvated protein and that of the pure solvent, we settled the same experimental conditions and applied the same data analysis procedure as in Paciaroni et al. (Biophys. J. 83 (2002) 1157). By using a double-well model and taking into account for the global molecular diffusion, we exploited the measured intensity to estimate the mean square displacements (MSD) of glycerol hydrogen atoms. We found that the total MSD deviate from the low-temperature vibrational harmonic trend at approximately T=235 K, consistent with the value of the critical temperature reported in literature (Phys. Rev. E 55 (1997) 3183). The present investigation suggests that the internal dynamics of glycerol molecules, i.e. the vibrations and reorientations of hydrogen atoms relative to the molecular centre of mass (c.o.m.), can be put in relationship with the protein dynamics

  20. (glycerol-phthalate) based alkyd coating exposed to outdoor weather

    African Journals Online (AJOL)

    The effects of weathering on poly(glycerol-phthalate) based alkyd coatings of the unstabilised and stabilised samples using varying amounts of dibutyltin distearate have been studied. The weathering and stabilization processes were monitored using infrared spectroscopy,gel formation, colour development, tensile strength ...

  1. Liquid phase conversion of Glycerol to Propanediol over highly ...

    Indian Academy of Sciences (India)

    high acidic strength. Further, the effects of temperature, hydrogen pressure, catalyst loading and glycerol con- centration were studied over 25Cu/MgO catalyst for optimization of reaction parameters. Kinetic .... ous sodium hydrogen carbonate solution until the pH ... Temperature programmed reduction experiments with.

  2. Utilization of a waste glycerol fraction using and reusing immobilized Gluconobacter oxydans ATCC 621 cell extract

    Directory of Open Access Journals (Sweden)

    Lidia Stasiak-Różańska

    2017-05-01

    Conclusions: The method proposed in this work is based on the conversion of waste glycerol to dihydroxyacetone in a reaction catalyzed by immobilized Gluconobacter oxydans cell extract with glycerol dehydrogenase activity, and it could be an effective way to convert waste glycerol into a valuable product.

  3. Glycerol reforming and methanol synthesis for the production of renewable methanol

    NARCIS (Netherlands)

    van Bennekom, Joost Gerardus

    2013-01-01

    De productie van biodiesel is flink toegenomen in het eerste decennium van de 21ste eeuw. Bij de productie van 100 kg biodiesel komt ongeveer 10 kg aan glycerol vrij, wat heeft geleid tot een sterk gestegen glycerol aanbod. Een mogelijkheid om wat met de glycerol te doen, is het omzetten van

  4. Glycerol fermentation to hydrogen by Thermotoga maritima: Proposed pathway and bioenergetic considerations

    NARCIS (Netherlands)

    Maru, B.T.; Bielen, A.A.M.; Constanti, M.; Medina, F.; Kengen, S.W.M.

    2013-01-01

    The production of biohydrogen from glycerol, by the hyperthermophilic bacterium Thermotoga maritima DSM 3109, was investigated in batch and chemostat systems. T. maritima converted glycerol to mainly acetate, CO2 and H2. Maximal hydrogen yields of 2.84 and 2.41 hydrogen per glycerol were observed

  5. Recovery and characterization of poly(3-Hydroxybutyric acid ...

    African Journals Online (AJOL)

    Darshan

    0.71 and finally IR spectrum of the compounds showed characteristics bands for the groups CH, C=O and C-O, indicating the presence of PHB in the ... that plant oils are desirable feed stocks for PHA production because they are also ... Characterization of PHB. The chemical structure and the thermal properties of PHB were ...

  6. Recovery and characterization of poly(3-Hydroxybutyric acid ...

    African Journals Online (AJOL)

    Darshan

    Recovered PHB sample was estimated by UV spectrophotometer. PHB from S. epidermidis was characterized and by these findings, we examined purified PHB by differential scanning calorimeter (DSC), a thermo gravimetric analyzer. (TGA), thin layer chromatography (TLC) and infrared spectroscopy (IR). The results of our ...

  7. Recovery and characterization of poly(3-Hydroxybutyric acid ...

    African Journals Online (AJOL)

    Recovered PHB sample was estimated by UV spectrophotometer. PHB from S. epidermidis was characterized and by these findings, we examined purified PHB by differential scanning calorimeter (DSC), a thermo gravimetric analyzer (TGA), thin layer chromatography (TLC) and infrared spectroscopy (IR). The results of our ...

  8. Microbial synthesis of poly(3-hydroxybutyrate-co-4- hydroxybutyrate ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-09-01

    Certomat R and H, B. Braun, Germany) at 30°C and 200 rpm. Two replicates were prepared for each culture medium. Analytical procedures. PHA content and composition in the lyophilized cell material were determined using gas ...

  9. Glycolysis of poly (3-hydroxybutyrate) catalyzed by an enzyme system

    International Nuclear Information System (INIS)

    Campos, T.F.; Mano, V.

    2010-01-01

    In this work we report the studies of PHB glycolysis catalyzed by lipase Amano PS (Pseudomonas cepacia) in the presence of 1,2-ethanediol (ethylene glycol). The reactions were performed in toluene:dichloroethane 3:1 (v/v) at 60 deg C, varying reaction time and concentration of ethylene glycol. PHB and the products of glycolysis (polyols) were characterized by FTIR, 1 H-NMR, and TG. The FTIR spectra of polyols showed no significant change compared to the spectrum of PHB. The 1 H-NMR spectra of the products of glycolysis showed signs of interest between 3 and 4.7 ppm, related to the ethylene glycol protons inserted in the polymer chain. By analyzing the thermograms we observed that the polyols are more thermally stable than PHB. (author)

  10. Microbial synthesis of poly(3-hydroxybutyrate-co-4- hydroxybutyrate ...

    African Journals Online (AJOL)

    hydroxybutyrate) [P(3HB-co-4HB)] in a two step cultivation process on a medium containing g-butyrolactone as the carbon source. A high fraction of 4HB monomer unit was obtained by manipulating the cell concentration, types of carbon sources ...

  11. The effect of hepatectomy on glucose homeostasis in pig and in man

    DEFF Research Database (Denmark)

    Lauritsen, Torsten Leif Bunk; Grunnet, Niels; Rasmussen, Allan

    2002-01-01

    BACKGROUND/AIMS: The liver is regarded the most important source of glucose production and it is common practice to administer glucose during human liver transplantations to avoid hypoglycaemia. The purpose of this study was to evaluate the importance of extra-hepatic contribution (kidney, gut......, glycerol, alanine and free fatty acids were measured over kidney, gut and hind leg in 18 pigs made anhepatic. RESULTS: Blood glucose did not change significantly and blood lactate increased only marginally during the anhepatic phase of human orthotopic liver transplantation. In the anhepatic pig, however...

  12. Transcriptome profiling of brown adipose tissue during cold exposure reveals extensive regulation of glucose metabolism

    DEFF Research Database (Denmark)

    Hao, Qin; Yadav, Rachita; Basse, Astrid L.

    2015-01-01

    We applied digital gene expression profiling to determine the transcriptome of brown and white adipose tissues (BAT and WAT, respectively) during cold exposure. Male C57BL/6J mice were exposed to cold for 2 or 4 days. A notable induction of genes related to glucose uptake, glycolysis, glycogen...... exposure, we propose a model for the intermediary glucose metabolism in activated BAT: 1) fluxes through glycolysis and the pentose phosphate pathway are induced, the latter providing reducing equivalents for de novo fatty acid synthesis; 2) glycerol synthesis from glucose is increased, facilitating...

  13. Determination of glycerol concentrations and glycerol isotopic enrichments in human plasma by gas chromatography/mass spectrometry

    NARCIS (Netherlands)

    Ackermans, M. T.; Ruiter, A. F.; Endert, E.

    1998-01-01

    An analytical method is presented to determine glycerol concentrations and stable isotope tracer enrichments in human plasma after intravenous tracer infusion in a single analytical run, using gas chromatography coupled to mass spectrometry. The method uses an internal standard, which is also a

  14. Crystallization and transformation of polymorphic forms of trioleoyl glycerol and 1,2-dioleoyl-3-rac-linoleoyl glycerol.

    Science.gov (United States)

    Bayés-García, Laura; Calvet, Teresa; Cuevas-Diarte, Miquel Àngel; Ueno, Satoru; Sato, Kiyotaka

    2013-08-08

    This study examined the influence of different thermal treatments on the crystallization and transformation of trioleoyl glycerol (OOO) and 1,2-dioleoyl-3-rac-linoleoyl glycerol (OOL). Two triacylglycerol (TAG) samples were cooled at 0.5-15 °C·min(-1) and heated at 2 and 15 °C·min(-1). The polymorphic characteristics of the two TAGs were analyzed in situ using differential scanning calorimetry, Raman spectroscopy, and synchrotron radiation X-ray diffraction. Multiple polymorphic forms were identified in OOO (α, β'2, β'1, β2, and β1) and OOL (α, β'2, and β'1). Larger quantities of more stable forms (e.g., β2 and β1 of OOO and β'1 of OOL) were obtained when the samples were slowly cooled and heated. In contrast, less stable polymorphs were obtained with increased cooling and heating rates. Polymorphic transformations occurred in either solid-state or melt-mediation and were influenced by heating rates. The results were analyzed by considering the activation energies for crystallization and transformation of stable and less stable polymorphic forms in comparison with previous studies on 1,3-dipalmitoyl-2-oleoyl-glycerol and 1, 3-dioleoyl-2-palmitoyl-glycerol.

  15. Value-added uses for crude glycerol--a byproduct of biodiesel production

    Directory of Open Access Journals (Sweden)

    Yang Fangxia

    2012-03-01

    Full Text Available Abstract Biodiesel is a promising alternative, and renewable, fuel. As its production increases, so does production of the principle co-product, crude glycerol. The effective utilization of crude glycerol will contribute to the viability of biodiesel. In this review, composition and quality factors of crude glycerol are discussed. The value-added utilization opportunities of crude glycerol are reviewed. The majority of crude glycerol is used as feedstock for production of other value-added chemicals, followed by animal feeds.

  16. Glycerol as source of energy in broiler chicken fattening

    Directory of Open Access Journals (Sweden)

    Leo Kroupa

    2011-01-01

    Full Text Available The objective of this study was to verify the possibility of replacing soybean oil in a diet with glycerol, and investigate the effect of glycerol on performance indicators and health in broiler chickens. The experiment was performed on 122 one-day-old chickens that were divided based on sex into two control groups (30 females and 31 males and two experimental groups (30 females and 31 males. Half (50% of the soybean oil in diets used in the experimental groups was replaced with glycerol at a ratio of 1:2. On 15, 32 and 38 day of age chickens of both sexes in the experimental group that were fed with diets containing glycerol showed significantly higher (p ≤ 0.01 mean body weight compared to the control group. At the end of the experiment, the mean weight of chickens in the control group was 2.078 kg, whereas the mean weight of chickens in the experimental group was 2.341 kg. In females, the overall consumption of diets within 38 days of fattening was 3.588 kg in the control group and 4.011 kg in the experimental group, in males, it was 3.915 kg in the control group and 4.366 kg in the experimental group, i.e. it was higher in experimental chickens. Feed conversion in chickens in experimental groups was better, being 1.84 kg in the control group and 1.81 kg in the experimental group in females, and 1.73 kg in the control group and 1.72 kg in the experimental group in males. It follows from our results that the optimum amount of glycerol in feed for poultry is 5%.This study presents an original solution to optimize feed formula by replacing plant oil with glycerol. The results of the study can improve production indicators and economy in broiler fattening.

  17. CSF glucose test

    Science.gov (United States)

    Glucose test - CSF; Cerebrospinal fluid glucose test ... The glucose level in the CSF should be 50 to 80 mg/100 mL (or greater than 2/3 ... Abnormal results include higher and lower glucose levels. Abnormal ... or fungus) Inflammation of the central nervous system Tumor

  18. Experimentally Induced Bleaching in the Sea Anemone Exaiptasia Supports Glucose as a Main Metabolite Associated with Its Symbiosis

    Directory of Open Access Journals (Sweden)

    Víctor Hugo Molina

    2017-01-01

    Full Text Available Our current understanding of carbon exchange between partners in the Symbiodinium-cnidarian symbioses is still limited, even though studies employing carbon isotopes have made us aware of the metabolic complexity of this exchange. We examined glycerol and glucose metabolism to better understand how photosynthates are exchanged between host and symbiont. The levels of these metabolites were compared between symbiotic and bleached Exaiptasia pallida anemones, assaying enzymes directly involved in their metabolism. We measured a significant decrease of glucose levels in bleached animals but a significant increase in glycerol and G3P pools, suggesting that bleached animals degrade lipids to compensate for the loss of symbionts and seem to rely on symbiotic glucose. The lower glycerol 3-phosphate dehydrogenase but higher glucose 6-phosphate dehydrogenase specific activities measured in bleached animals agree with a metabolic deficit mainly due to the loss of glucose from the ruptured symbiosis. These results corroborate previous observations on carbon translocation from symbiont to host in the sea anemone Exaiptasia, where glucose was proposed as a main translocated metabolite. To better understand photosynthate translocation and its regulation, additional research with other symbiotic cnidarians is needed, in particular, those with calcium carbonate skeletons.

  19. Microbial conversion of glycerol into glycolipid biosurfactants, mannosylerythritol lipids, by a basidiomycete yeast, Pseudozyma antarctica JCM 10317(T).

    Science.gov (United States)

    Morita, Tomotake; Konishi, Masaaki; Fukuoka, Tokuma; Imura, Tomohiro; Kitamoto, Dai

    2007-07-01

    Microbial conversion of glycerol into functional bio-based materials was investigated, aiming to facilitate the utilization of waste glycerol. A basidiomycete yeast, Pseudozyma antarctica JCM 10317, efficiently produced mannosylerythritol lipids (MELs) as glycolipid biosurfactants from glycerol. The amount of MEL yield reached 16.3 g l(-1) by intermittent feeding of glycerol.

  20. Preparo e caracterização de micropartículas de acetobutirato de celulose e poli(3-hidroxibutirato contendo piroxicam - DOI: 10.4025/actascihealthsci.v31i1.4428 Preparation and characterization of cellulose acetate butyrate and poly(3-hydroxybutyrate microparticles containing piroxicam - DOI: 10.4025/actascihealthsci.v31i1.4428

    Directory of Open Access Journals (Sweden)

    Melissa Zétola

    2009-05-01

    Full Text Available O objetivo deste trabalho foi avaliar a influência da massa molar do acetobutirato de celulose (ABC e da adição de poli(3-hidroxibutirato [PHB] sobre a morfologia das micropartículas, a eficiência de encapsulação e os perfis de liberação do piroxicam. As micropartículas foram preparadas por meio da técnica de emulsão/evaporação do solvente O/A e caracterizadas quanto à morfologia por microscopia eletrônica de varredura. O teor de fármaco nas micropartículas foi determinado utilizando o método de espectrofotometria de absorção na região do ultravioleta; os ensaios de liberação realizados, utilizando tampão fosfato pH 6,8. As micropartículas obtidas apresentaram formas irregulares, e aquelas preparadas a partir do ABC com maior massa molar apresentaram maior tamanho. Mediante planejamento fatorial, observou-se que as variáveis analisadas (massa molar do ABC e adição de PHB não influenciaram a eficiência de encapsulação do piroxicam, mas exerceram influência sobre a quantidade inicial de piroxicam liberada a partir das micropartículas.This work aims to evaluate the influence of the cellulose acetate butyrate (CAB molar weight and the addition of poly(3-hydroxybutyrate [PHB] on microparticle morphology, encapsulation efficiency and release profile of piroxicam. The microparticles were prepared using the O/W emulsion/solvent evaporation technique and characterized according to the morphology using scanning electron microscopy. The drug content in the microparticles was determined through UV spectrophotometry and a dissolution assay was conducted using phosphate buffer pH 6.8. The obtained microparticles presented irregular shape; the ones prepared with CAB with large molar weight presented a larger size. Through a factorial design, it was observed that the analyzed variables (CAB molar weight and PHB addition did not influence the encapsulation efficiency, but did influence the initial release of piroxicam from the

  1. Sodahvede og glycerol til malkekøer

    DEFF Research Database (Denmark)

    Hvelplund, Torben; Weisbjerg, Martin Riis

    2011-01-01

    Et fodringsforsøg på Kvægbrugets Forsøgscenter har vist, at glycerol kan anvendes som et alternativt fodermiddel til højtydende malkekøer. De anvendte mængder gav dog en lavere EKM ydelse end sodahvede, men øgede samtidigt mælkens proteinindhold.......Et fodringsforsøg på Kvægbrugets Forsøgscenter har vist, at glycerol kan anvendes som et alternativt fodermiddel til højtydende malkekøer. De anvendte mængder gav dog en lavere EKM ydelse end sodahvede, men øgede samtidigt mælkens proteinindhold....

  2. Modified silica-based heterogeneous catalysts for etherification of glycerol

    Energy Technology Data Exchange (ETDEWEB)

    Gholami, Zahra, E-mail: zahra.gholami@petronas.com.my [Centralized Analytical Laboratory, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Abdullah, Ahmad Zuhairi, E-mail: chzuhairi@usm.my; Gholami, Fatemeh, E-mail: fgholami59@gmail.com [School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus,14300 Nibong Tebal, Penang (Malaysia); Vakili, Mohammadtaghi, E-mail: farshid3601@gmail.com [School of Industrial Technology, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2015-07-22

    The advent of mesoporous silicas such as MCM-41 has provided new opportunities for research into supported metal catalysis. The loading of metals into framework structures and particularly into the pores of porous molecular sieves, has long been of interest because of their potential catalytic activity. Stable heterogeneous mesoporous basic catalysts were synthesized by wet impregnation of MCM-41 with calcium nitrate and lanthanum nitrate. The surface and structural properties of the prepared catalysts were characterized using BET surface analysis, SEM and TEM. MCM-41 and modified MCM-41 were used in the solventless etherification of glycerol to produce diglycerol as the desired product. The reaction was performed at 250 °C for 8 h, and catalyst activity was evaluated. Catalytic etherification over the 20%Ca{sub 1.6}La{sub 0.6}/MCM-41 catalyst resulted in the highest glycerol conversion of 91% and diglycerol yield of 43%.

  3. Gut Microbial Glycerol Metabolism as an Endogenous Acrolein Source

    Directory of Open Access Journals (Sweden)

    Jianbo Zhang

    2018-01-01

    Full Text Available Acrolein is a highly reactive electrophile causing toxic effects, such as DNA and protein adduction, oxidative stress, endoplasmic reticulum stress, immune dysfunction, and membrane damage. This Opinion/Hypothesis provides an overview of endogenous and exogenous acrolein sources, acrolein’s mode of action, and its metabolic fate. Recent reports underpin the finding that gut microbial glycerol metabolism leading to the formation of reuterin is an additional source of endogenous acrolein. Reuterin is an antimicrobial multicomponent system consisting of 3-hydroxypropionaldehyde, its dimer and hydrate, and also acrolein. The major conclusion is that gut microbes can metabolize glycerol to reuterin and that this transformation occurs in vivo. Given the known toxicity of acrolein, the observation that acrolein is formed in the gut necessitates further investigations on functional relevance for gut microbiota and the host.

  4. Gut Microbial Glycerol Metabolism as an Endogenous Acrolein Source

    OpenAIRE

    Zhang, Jianbo; Sturla, Shana; Lacroix, Christophe; Schwab, Clarissa

    2018-01-01

    ABSTRACT Acrolein is a highly reactive electrophile causing toxic effects, such as DNA and protein adduction, oxidative stress, endoplasmic reticulum stress, immune dysfunction, and membrane damage. This Opinion/Hypothesis provides an overview of endogenous and exogenous acrolein sources, acrolein’s mode of action, and its metabolic fate. Recent reports underpin the finding that gut microbial glycerol metabolism leading to the formation of reuterin is an additional source of endogenous acrole...

  5. Antibacterial effect of glycerol as preservative on donor skin

    International Nuclear Information System (INIS)

    Van Baare, J.; Ligtvoet, E.E.J.; Middelkoop, E.

    1999-01-01

    Glycerolised cadavetic allografts have been used widely since 1984 in the treatment of bum wounds. Rejections reaction to glycerolised skin were reported to be attenuated. Structural integrity of the skin was maintained and antiviral and antibacterial effects were noted. The Euro Skin Bank has gathered approximately 2000 data since 1987 concerning bacteriology cultures of glycerolised skin. These data are presented. Bacteriological data from skin donors were examined from 1987 till 1995 (1927 data). Donor skin sent to the laboratory and found to be positive for bacteria was quarantined and another container with skin samples was sent to the laboratory at a later time point. This was repeated until all cultures were negative. In 1987, 25 donors were processed without using antibiotics. These results were compared with donor skin treated with antibiotics. The average day for first culture was 19.7 ? 17.2. The average percentage of contaminated skin was 10.1? 3.7%. Antibiotics reduced contamination of glycerolised skin from 80% to 10.1%. Glycerol treatment also showed an antibacterial effect as all contaminated skin eventually became negative. Of the contaminated skin Staphylococcus epidermidis was found most frequently: in 70.7 ? 10.8% of the cases. Not all bacteria are equally sensitive to glycerol: Staphylococcus epidennidis contaminated skin became sterile after 48?24 days, whereas for Bacillus species it took 195? 1 37.9 days. We show that glycerol preservation of donor skin has important advantages over conservative methods such as cryopreservation. Initial contamination of the skin is no longer a reason to discard the material. Prolonged storage in glycerol will eliminate bacterial contamination. This allows an increase in yield of at least 10%

  6. Bio-Propane from glycerol for biogas addition

    Energy Technology Data Exchange (ETDEWEB)

    Brandin, Jan; Hulteberg, Christian; Liljegren Nilsson, Andreas (Biofuel-Solution AB, Malmoe (Sweden))

    2008-11-15

    In this report, the technical and economical feasibility to produce higher alkanes from bioglycerol has been investigated. The main purpose of producing this kind of chemicals would be to replace the fossil LPG used in upgraded biogas production. When producing biogas and exporting it to the natural gas grid, the Wobbe index and heating value does not match the existing natural gas. Therefore, the upgraded biogas that is put into the natural gas grid in Sweden today contains 8-10 vol-% of LPG. The experimental work performed in association to this report has shown that it is possible to produce propane from glycerol. However, the production of ethane from glycerol may be even more advantageous. The experimental work has included developing and testing catalysts for several intermediate reactions. The work was performed using different micro-scale reactors with a liquid feed rate of 18 g/h. The first reaction, independent on if propane or ethane is to be produced, is dehydration of glycerol to acrolein. This was showed during 60 h on an acidic catalyst with a yield of 90%. The production of propanol, the second intermediate to producing propane, was shown as well. Propanol was produced both using acrolein as the starting material as well as glycerol (combining the first and second step) with yields of 70-80% in the first case and 65-70% in the second case. The propanol produced was investigated for its dehydration to propene, with a yield of 70-75%. By using a proprietary, purposely developed catalyst the propene was hydrogenated to propane, with a yield of 85% from propanol. The formation of propane from glycerol was finally investigated, with an overall yield of 55%. The second part of the experimental work performed investigated the possibilities of decarbonylating acrolein to form ethane. This was made possible by the development of a proprietary catalyst which combines decarbonylation and water-gas shift functionality. By combining these two functionalities, no

  7. Methanol-dependent production of dihydroxyacetone and glycerol by mutants of the methylotrophic yeast Hansenula polymorpha blocked in dihydroxyacetone kinase and glycerol kinase

    NARCIS (Netherlands)

    Koning, W. de; Weusthuis, R.A.; Harder, W.; Dijkhuizen, L.

    Various factors controlling dihydroxyacetone (DHA) and glycerol production from methanol by resting cell suspensions of a mutant of Hansenula polymorpha, blocked in DHA kinase and glycerol kinase, were investigated. The presence of methanol (250 mM) and an additional substrate (0.5%, w/v) to

  8. A thermodynamic study of 1-propanol-glycerol-H2O at 25 degrees C: Effect of glycerol on molecular organization of H2O

    DEFF Research Database (Denmark)

    Parsons, M.T.; Westh, Peter; Davies, J.V.

    2001-01-01

    The excess chemical potential, partial molar enthalpy, and volume of 1-propanol were determined in ternary mixtures of 1-propanol-glycerol-H2O at 25degreesC. The mole fraction dependence of all these thermodynamic functions was used to elucidate the effect of glycerol on the molecular organization...

  9. Influence of lake water pH and alkalinity on the distribution of coreand intact polar branched glycerol dialkyl glycerol tetraethers (GDGTs) in lakes

    NARCIS (Netherlands)

    Schoon, P.L.; de Kluijver, A.; Middelburg, J.J.; Downing, J.A.; Sinninghe Damsté, J.S.; Schouten, S.

    2013-01-01

    Branched glycerol dialkyl glycerol tetraethers (GDGTs) are bacterial membrane lipids, ubiquitously present in soils and peat bogs, as well as in rivers, lakes and lake sediments. Their distribution in soil is controlled mainly by pH and mean annual air temperature, but the controls on their

  10. Seasonal changes in glycerol dialkyl glycerol tetraether concentrations and fluxes in a perialpine lake: Implications for the use of the TEX

    NARCIS (Netherlands)

    Blaga, C.I.; Reichart, G.J.; Vissers, E.W.; Lotter, A.F.; Anselmetti, F.S.; Sinninghe Damsté, J.S.; Sinninghe Damsté, J.S.

    2011-01-01

    To determine where and when glycerol dialkyl glycerol tetraether (GDGT) membrane lipids in lakes are produced, we collected descending particles in Lake Lucerne (Switzerland) using two sediment traps (at 42 and 72 m water depth) with a monthly resolution from January 2008 to late March 2009.

  11. Influence of lake water pH and alkalinity on the distribution of core and intact polar branched glycerol dialkyl glycerol tetraethers (GDGTs) in lakes

    NARCIS (Netherlands)

    Schoon, P.L.; de Kluijver, A.; Middelburg, J.J.; Downing, J.A.; Sinninghe Damsté, J.S.; Schouten, S.

    2013-01-01

    Branched glycerol dialkyl glycerol tetraethers (GDGTs) are bacterial membrane lipids, ubiquitously present in soils and peat bogs, as well as in rivers, lakes and lake sediments. Their distribution in soil is controlled mainly by pH and mean annual air temperature, but the controls on their

  12. Impact of riverine suspended particulate matter on the branched glycerol dialkyl glycerol tetraether composition of lakes: The outflow of the Selenga River in Lake Baikal (Russia)

    NARCIS (Netherlands)

    De Jonge, C.; Stadnitskaia, A.; Fedotov, A.; Sinninghe Damsté, J.S.

    2015-01-01

    Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids found in several environments, including soils, rivers and lakes, whose distribution varies with temperature and pH, although this dependence is apparently not the same for the different environments. Mixing of

  13. Flavor impacts of glycerol in the processing of yeast fermented beverages: a review.

    Science.gov (United States)

    Zhao, Xiangdong; Procopio, Susanne; Becker, Thomas

    2015-12-01

    Glycerol contributes to the beverage body and fullness. Moreover, it also influences the flavor intensity. As a major byproduct, glycerol not only serves critical roles in yeast osmoregulation and redox balancing, but also acts as the carbon competitor against ethanol in alcoholic fermentation. Therefore, increasing glycerol yield benefits both the flavor and ethanol reduction for the fermented beverages. Glycerol yield has been elevated either by fermentation optimization or by yeast genetic modification. The fermentation optimizations reached maximum 14 g/L glycerol through screening yeast strains and optimizing fermentation parameters. Meanwhile the yeast overexpressing GPD1 (encoding glycerol-3-phosphate dehydrogenase) produced up to 6 folds more glycerol for beer and wine. Except for glycerol improvement, the genetically modified yeasts accumulated dramatically undesirable compounds such as acetaldehyde, acetate and acetoin which are detrimental for beverage flavor. In comparison, the natural high glycerol producers showed strain-specific manner on the yeast-derived aroma compounds like volatile acids, fusel alcohols, esters, and aldehydes. Temperature, sugar concentration, nitrogen composition, oxygen and pH-value, which influence glycerol biosynthesis, also obtained various effects on the production of aromatic compounds. In the current review, we firstly deliberate the organoleptic contributions of glycerol for fermented beverages. Furthermore, glycerol optimization strategies are discussed regarding to the yield improvement, the genes expressions, the overall flavor impacts and the feasibilities in beverage applications. Lastly, for improving beverage flavor by glycerol optimization, a high-throughput platform is proposed to increase the screening capacity of yeast strains and parameters in the processing of fermented beverages.

  14. A thermodynamic study of 1-propanol-glycerol-H2O at 25 degrees C: Effect of glycerol on molecular organization of H2O

    DEFF Research Database (Denmark)

    Parsons, M.T.; Westh, Peter; Davies, J.V.

    2001-01-01

    The excess chemical potential, partial molar enthalpy, and volume of 1-propanol were determined in ternary mixtures of 1-propanol-glycerol-H2O at 25degreesC. The mole fraction dependence of all these thermodynamic functions was used to elucidate the effect of glycerol on the molecular organization...... of H2O. The glycerol molecules do not exert a hydrophobic effect on H2O. Rather, the hydroxyl groups of glycerol, perhaps by forming clusters via its alkyl backbone with hydroxyl groups pointing outward, interact with H2O so as to reduce the characteristics of liquid H2O. The global hydrogen bond...... probability and, hence, the percolation nature of the hydrogen bond network is reduced. In addition, the degree of fluctuation inherent in liquid H2O is reduced by glycerol perhaps by participating in the hydrogen bond network via OH groups. At infinite dilution, the pair interaction coefficients in enthalpy...

  15. Four grams of glucose

    OpenAIRE

    Wasserman, David H.

    2008-01-01

    Four grams of glucose circulates in the blood of a person weighing 70 kg. This glucose is critical for normal function in many cell types. In accordance with the importance of these 4 g of glucose, a sophisticated control system is in place to maintain blood glucose constant. Our focus has been on the mechanisms by which the flux of glucose from liver to blood and from blood to skeletal muscle is regulated. The body has a remarkable capacity to satisfy the nutritional need for glucose, while ...

  16. Lactose autoinduction with enzymatic glucose release: characterization of the cultivation system in bioreactor.

    Science.gov (United States)

    Mayer, Sonja; Junne, Stefan; Ukkonen, Kaisa; Glazyrina, Julia; Glauche, Florian; Neubauer, Peter; Vasala, Antti

    2014-02-01

    The lactose autoinduction system for recombinant protein production was combined with enzymatic glucose release as a method to provide a constant feed of glucose instead of using glycerol as a carbon substrate. Bioreactor cultivation confirmed that the slow glucose feed does not prevent the induction by lactose. HPLC studies showed that with successful recombinant protein production only a very low amount of lactose was metabolized during glucose-limited fed-batch conditions by the Escherichia coli strain BL21(DE3)pLysS in well-aerated conditions, which are problematic for glycerol-based autoinduction systems. We propose that slow enzymatic glucose feed does not cause a full activation of the lactose operon. However recombinant PDI-A protein (A-domain of human disulfide isomerase) was steadily produced until the end of the cultivation. The results of the cultivations confirmed our earlier observations with shaken cultures showing that lactose autoinduction cultures based on enzymatic glucose feed have good scalability, and that this system can be applied also to bioreactor cultivations. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Value-added processing of crude glycerol into chemicals and polymers.

    Science.gov (United States)

    Luo, Xiaolan; Ge, Xumeng; Cui, Shaoqing; Li, Yebo

    2016-09-01

    Crude glycerol is a low-value byproduct which is primarily obtained from the biodiesel production process. Its composition is significantly different from that of pure glycerol. Crude glycerol usually contains various impurities, such as water, methanol, soap, fatty acids, and fatty acid methyl esters. Considerable efforts have been devoted to finding applications for converting crude glycerol into high-value products, such as biofuels, chemicals, polymers, and animal feed, to improve the economic viability of the biodiesel industry and overcome environmental challenges associated with crude glycerol disposal. This article reviews recent advances of biological and chemical technologies for value-added processing of crude glycerol into chemicals and polymers, and provides strategies for addressing production challenges. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Español Hyperglycemia (High Blood Glucose) Hyperglycemia is the technical term for high blood glucose (blood sugar). High ... We Are Research Leaders We Support Your Doctor Student Resources Patient Access to Research Research Resources Practice ...

  19. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Español Hyperglycemia (High Blood Glucose) Hyperglycemia is the technical term for high blood glucose (blood sugar). High ... Type 2 Diabetes program to get help and support during your first year. Featured Book Type 2 ...

  20. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... and eAG Hypoglycemia (Low blood glucose) Hyperglycemia (High blood glucose) Dawn Phenomenon Checking for Ketones Tight Diabetes Control donate en -- A Future Without Diabetes - a-future- ...

  1. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Blood Pressure Physical Activity High Blood Glucose My Health Advisor Tools To Know Your Risk Alert Day ... DKA (Ketoacidosis) & Ketones Kidney Disease (Nephropathy) Gastroparesis Mental Health Step On Up Treatment & Care Blood Glucose Testing ...

  2. Glucose-6-phosphate dehydrogenase

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003671.htm Glucose-6-phosphate dehydrogenase test To use the sharing features on this page, please enable JavaScript. Glucose-6-phosphate dehydrogenase (G6PD) is a protein that ...

  3. Glucose test (image)

    Science.gov (United States)

    ... person with diabetes constantly manages their blood's sugar (glucose) levels. After a blood sample is taken and tested, it is determined whether the glucose levels are low or high. Following your health ...

  4. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... symptoms include the following: High blood glucose High levels of sugar in the urine Frequent urination Increased ... you should check and what your blood glucose levels should be. Checking your blood and then treating ...

  5. Synthesis of Acrolein From Glycerol Using FePO4 Catalyst in Liquid Phase Dehydration

    OpenAIRE

    Abidin, Akhmad Zainal; Afandi, Rani Guslianti; Graha, Hafis Pratama Rendra

    2016-01-01

    Acrolein is currently produced using propylene from crude oil while its price and scarcity are increasing. A renewable material such as glycerol is an attractive alternative for acrolein production. It can be obtained from crude palm oil (CPO) and is a byproduct of biodiesel production. Besides being able to compete economically, glycerol is an environmentally friendly material. The purpose of this study is to synthesize acrolein from glycerol using FePO4 catalyst in liquid phase dehydration....

  6. Quantitative analysis of glycerol accumulation, glycolysis and growth under hyper osmotic stress.

    Directory of Open Access Journals (Sweden)

    Elzbieta Petelenz-Kurdziel

    Full Text Available We provide an integrated dynamic view on a eukaryotic osmolyte system, linking signaling with regulation of gene expression, metabolic control and growth. Adaptation to osmotic changes enables cells to adjust cellular activity and turgor pressure to an altered environment. The yeast Saccharomyces cerevisiae adapts to hyperosmotic stress by activating the HOG signaling cascade, which controls glycerol accumulation. The Hog1 kinase stimulates transcription of genes encoding enzymes required for glycerol production (Gpd1, Gpp2 and glycerol import (Stl1 and activates a regulatory enzyme in glycolysis (Pfk26/27. In addition, glycerol outflow is prevented by closure of the Fps1 glycerol facilitator. In order to better understand the contributions to glycerol accumulation of these different mechanisms and how redox and energy metabolism as well as biomass production are maintained under such conditions we collected an extensive dataset. Over a period of 180 min after hyperosmotic shock we monitored in wild type and different mutant cells the concentrations of key metabolites and proteins relevant for osmoadaptation. The dataset was used to parameterize an ODE model that reproduces the generated data very well. A detailed computational analysis using time-dependent response coefficients showed that Pfk26/27 contributes to rerouting glycolytic flux towards lower glycolysis. The transient growth arrest following hyperosmotic shock further adds to redirecting almost all glycolytic flux from biomass towards glycerol production. Osmoadaptation is robust to loss of individual adaptation pathways because of the existence and upregulation of alternative routes of glycerol accumulation. For instance, the Stl1 glycerol importer contributes to glycerol accumulation in a mutant with diminished glycerol production capacity. In addition, our observations suggest a role for trehalose accumulation in osmoadaptation and that Hog1 probably directly contributes to the

  7. Effects of sorbitol and glycerol on the structure, dynamics, and stability of Mycobacterium tuberculosis pyrazinamidase

    Directory of Open Access Journals (Sweden)

    Mehrnoosh Khajehzadeh

    2016-01-01

    Conclusion: It can be concluded that the native conformation of the enzyme was stabilized in the sorbitol and glycerol and tend to exclude from the PZase surface, forcing the enzyme to keep it in the compactly folded conformation. The glycerol molecules stabilized PZase by decreasing the loops flexibility and then compacting the enzyme structure. It appears that more stability of PZase in glycerol solution correlates with its amphiphilic orientation, which decreases the unfavorable interactions of hydrophobic regions.

  8. [Blood glucose self monitoring].

    Science.gov (United States)

    Wascher, Thomas C; Stechemesser, Lars

    2016-04-01

    Self monitoring of blood glucose contributes to the integrated management of diabetes mellitus. It, thus, should be available for all patients with diabetes mellitus type-1 and type-2. Self monitoring of blood glucose improves patients safety, quality of life and glucose control. The current article represents the recommendations of the Austrian Diabetes Association for the use of blood glucose self monitoring according to current scientific evidence.

  9. Effects of ambient temperature and dietary glycerol addition on growth performance, blood parameters and immune cell populations of Korean cattle steers

    Directory of Open Access Journals (Sweden)

    Hyeok Joong Kang

    2017-04-01

    Full Text Available Objective This study was performed to evaluate whether ambient temperature and dietary glycerol addition affect growth performance, and blood metabolic and immunological parameters, in beef cattle. Methods Twenty Korean cattle steers (405.1±7.11 kg of body weight [BW], 14.2±0.15 months of age were divided into a conventional control diet group (n = 10 and a 2% glycerol- added group (n = 10. Steers were fed 1.6% BW of a concentrate diet and 0.75% BW of a timothy hay diet for 8 weeks (4 weeks from July 28th to August 26th and 4 weeks from August 27th to September 26th. Blood was collected four times on July 28th, August 11th, August 27th, and September 26th. Results The maximum indoor ambient temperature-humidity index in August (75.8 was higher (p<0.001 than that in September (70.0, and in August was within the mild heat stress (HS category range previously reported for dairy cattle. The average daily gain (ADG; p = 0.03 and feed efficiency (p<0.001 were higher in hotter August than in September. Glycerol addition did not affect ADG and feed efficiency. Neither month nor glycerol addition affected blood concentrations of cortisol, triglyceride, or non-esterified fatty acid. Blood concentrations of cholesterol, low-density lipoprotein, high-density lipoprotein, glucose, and albumin were lower (p<0.05 on August 27th than on September 26 th, and blood phosphorus, calcium and magnesium concentrations were also lower on August 27th than on September 27th. Glycerol addition did not affect these blood parameters. Percentages of CD4+ T cells and CD8+ T cells were higher (p<0.05 on July 28th than on August 27th and September 26th. The blood CD8+ T cell population was lower in the glycerol supplemented-group compared to the control group on July 28th and August 27th. Conclusion Korean cattle may not be significantly affected by mild HS, considering that growth performance of cattle was better in hotter conditions, although some changes in blood metabolic

  10. Expression and functional studies of genes involved in transport and metabolism of glycerol in Pachysolen tannophilus

    DEFF Research Database (Denmark)

    Liu, Xiaoying; Mortensen, Uffe Hasbro; Workman, Mhairi

    2013-01-01

    P. tannophilus has characteristics relevant for a microbial cell factory to be applied in a biorefinery setting, i.e. its ability to utilise the carbon sources such as xylose and glycerol. However, the strain is not currently amenable to genetic modification and transformation. Heterologous...... expression of the glycerol transporters from P. tannophilus, which has a relatively high growth rate on glycerol, could be used as an approach for improving the efficiency of glycerol assimilation in other well characterized and applied cell factories such as S. cerevisiae....

  11. Etherification of Glycerol with Propylene or 1-Butene for Fuel Additives

    Directory of Open Access Journals (Sweden)

    Chakrapong Saengarun

    2017-01-01

    Full Text Available The etherification of glycerol with propylene over acidic heterogeneous catalysts, Amberlyst-15, S100, and S200 resins, produced mono-propyl glycerol ethers (MPGEs, 1,3-di- and 1,2-di-propyl glycerol ethers (DPGEs, and tri-propyl glycerol ether (TPGE. The propylation of glycerol over Amberlyst-15 yielded only TPGE. The glycerol etherification with 1-butene over Amberlyst-15 and S200 resins produced 1-mono-, 2-mono-, 1,2-di-, and 1,3-di-butyl glycerol ethers (1-MBGE, 2-MBGE, 1,2-DBGE, and 1,3-DBGE. The use of Amberlyst-15 resulted in the propylation and butylation of glycerol with higher yields than those obtained from the S100 and S200 resins. The PGEs, TPGE, and BGEs were evaluated as cold flow improvers and octane boosters. These alkyl glycerol ethers can reduce the cloud point of blended palm biodiesels with diesel. They can increase the research octane number and the motor octane number of gasoline.

  12. Physical, Physicochemical, Mechanical, and Structural Characterization of Films Based on Gelatin/Glycerol and Carbon Nanotubes

    OpenAIRE

    Israel Sifuentes-Nieves; Rodolfo Rendón-Villalobos; Antonio Jiménez-Aparicio; Brenda Hildeliza Camacho-Díaz; Gustavo Fidel Gutiérrez López; Javier Solorza-Feria

    2015-01-01

    A new method to prepare glycerol/gelatin based films, by doping the film with carbon nanotubes (CNTs) and sodium dodecyl sulfate (SDS), was proposed. SDS was used to disperse CNTs in gelatin/glycerol films as follows: gelatin/glycerol (GG) incubated with equal concentrations of CNT and SDS; GG with 0.001% w/w CNT/SDS; GG with 0.002% CNT/SDS and GG with 0.004% CNT/SDS. Diffractograms of CNT/SDS /glycerol films showed an amorphous structure, being consistent with thermograms involving temperatu...

  13. Separation of oily sludge and glycerol from biodiesel processing waste by coagulation

    OpenAIRE

    Qiao-guang Xie1,; Wirach Taweepreda 2,; Charongpun Musikavong1*; Chaisri Suksaroj 1*

    2011-01-01

    Raw waste glycerol is a by-product of biodiesel production from transesterification, which is high in salt, and has a highpH value (more than 9.6). The purpose of this research is to reduce the water pollution from waste glycerol by using acoagulation process and discussing the possibility of waste glycerol reuse. The commercial coagulant (2% by weight), whichwas composed by cationic polyamine (PA) 6% and poly-aluminium chloride (PACl) 94% (w/w), was used as coagulant totreat waste glycerol. ...

  14. Dynamic shear modulus of glycerol: Corrections due to instrument compliance

    Science.gov (United States)

    Schröter, K.; Hutcheson, S. A.; Shi, X.; Mandanici, A.; McKenna, G. B.

    2006-12-01

    A recent article by Shi et al. [J. Chem. Phys.123, 174507 (2005)] reports results from mechanical measurements on three simple inorganic glass formers: glycerol, m-toluidine, and sucrose benzoate. The experiments carried out were stress relaxation, aging, and dynamic (all in shear) using a torsional rheometer, an advanced rheometric expansion system (TA Instruments). The original force rebalance transducer (2KFRT) supplied with the system was replaced with a custom-made load cell (Sensotec) that had a capacity of 20000gcm in torque and 5000g in normal force. The replacement of the load cell was done due to the belief that the main source of compliance in this instrument was from the 2KFRT. With this assumption, the authors published their results for the three materials of interest and compared their results with the techniques of Schröter and Donth [J. Chem. Phys.113, 9101 (2000)] for the measurements on glycerol and reported important differences. These differences were disputed by one of the present authors (Schröter), and the present report shows that the results from Schröter and Donth are correct. We show that the reasons have to do with the instrument compliance being greater than originally thought by Shi et al. Here we examine the effects of platen diameter/geometry on the glycerol dynamic moduli, describe a means to correct dynamic data, present a revised comparison of the corrected data with that of Schröter and Donth, and provide a discussion of future work and conclusions.

  15. Some experience of trigeminal neuralgia treatment by glycerol rhizolysis

    Directory of Open Access Journals (Sweden)

    А. В. Семенов

    2016-11-01

    Full Text Available Aim. The study was to evaluate the advantages and disadvantages of trigeminal neuralgia treatment by Hakanson S. glycerol rhizolysis method. Methods. The results of glycerol rhizolysis treatment were retrospectively evaluated in 96 patients with trigeminal neuralgia, who had been operated at Neurosurgical Department of Irkutsk City Hospital over a period from 2009 to 2016. To study the prospective follow-up, 53 patients operated during 2009 – 2014 were surveyed over the phone. The comparison of our long-term results and the results of other authors from literature sources was then performed.Results. The median of follow-up period was 43 months. The pain recurrence (III-V rate of Barrow Neurological Institute score for trigeminal neuralgia was observed in 30.2 % of patients, with the mean rate of the visual analogue scale amounting to 1.96. Complications included aseptic meningitis in 3.1 % cases, intracerebral hematoma – 1.04 %, hyperesthesia in appropriate trigeminal region – 3.8%, labial herpes – 40.7 %, temporary anesthesia in appropriate trigeminal region – 30.2%, temporary decrease of corneal reflex sensitivity – 41.5 %. There was no postoperative mortality.Conclusion. Glycerol rhizolysis is an effective method of trigeminal neuralgia treatment and its results are comparable with those of other surgical methods. Strict adherence to all surgical steps and contrast cistenography is the key to success of intervention. The method is minimally invasive, applicable for anesthesia and particularly promising for patients over 70 years old.Received 25 May 2016. Accepted 14 September 2016.Funding: The study had no sponsorship. Conflict of interest: The authors declare no conflict of interest.

  16. Pre-exercise glycerol hydration improves cycling endurance time

    Science.gov (United States)

    Montner, P.; Stark, D. M.; Riedesel, M. L.; Murata, G.; Robergs, R.; Timms, M.; Chick, T. W.

    1996-01-01

    The effects of glycerol ingestion (GEH) on hydration and subsequent cycle ergometer submaximal load exercise were examined in well conditioned subjects. We hypothesized that GEH would reduce physiologic strain and increase endurance. The purpose of Study I (n = 11) was to determine if pre-exercise GEH (1.2 gm/kg glycerol in 26 ml/kg solution) compared to pre-exercise placebo hydration (PH) (26 ml/kg of aspartame flavored water) lowered heart rate (HR), lowered rectal temperature (Tc), and prolonged endurance time (ET) during submaximal load cycle ergometry. The purpose of Study II (n = 7) was to determine if the same pre-exercise regimen followed by carbohydrate oral replacement solution (ORS) during exercise also lowered HR, Tc, and prolonged ET. Both studies were double-blind, randomized, crossover trials, performed at an ambient temperature of 23.5-24.5 degrees C, and humidity of 25-27%. Mean HR was lower by 2.8 +/- 0.4 beats/min (p = 0.05) after GEH in Study I and by 4.4 +/- 1.1 beats/min (p = 0.01) in Study II. Endurance time was prolonged after GEH in Study I (93.8 +/- 14 min vs. 77.4 +/- 9 min, p = 0.049) and in Study II (123.4 +/- 17 min vs. 99.0 +/- 11 min, p = 0.03). Rectal temperature did not differ between hydration regimens in both Study I and Study II. Thus, pre-exercise glycerol-enhanced hyperhydration lowers HR and prolongs ET even when combined with ORS during exercise. The regimens tested in this study could potentially be adapted for endurance activities.

  17. Synthesis and characterization of sulfonated polyesters derived from glycerol

    International Nuclear Information System (INIS)

    Fiuza, R.A.; Jose, N.M.; Boaventura, J.S.; Fiuza, R.P.

    2010-01-01

    In this work were synthesized polyesters from glycerol and acid sulfonated phthalic previously. The materials were characterized by DSC, TGA, FTIR, SEM, XRD and XRF. The results showed effective sulfonation of phthalic acid. The presence of sulfonic groups promoted strong changes in the crystallinity of the new material makes the lens. The polyesters made from phthalic acid sulfonated combine characteristics such as heat resistance and groups that drivers potentiate the electrolyte for application in fuel cells proton exchange membrane and also for gas separation. (author)

  18. Isolation of a solventogenic Clostridium sp. strain: fermentation of glycerol to n-butanol, analysis of the bcs operon region and its potential regulatory elements.

    Science.gov (United States)

    Panitz, J C; Zverlov, V V; Pham, V T T; Stürzl, S; Schieder, D; Schwarz, W H

    2014-02-01

    A new solventogenic bacterium, strain GT6, was isolated from standing water sediment. 16S-rRNA gene analysis revealed that GT6 belongs to the heterogeneous Clostridium tetanomorphum group of bacteria exhibiting 99% sequence identity with C. tetanomorphum 4474(T). GT6 can utilize a wide range of carbohydrate substrates including glucose, fructose, maltose, xylose and glycerol to produce mainly n-butanol without any acetone. Additional products of GT6 metabolism were ethanol, butyric acid, acetic acid, and trace amounts of 1,3-propanediol. Medium and substrate composition, and culture conditions such as pH and temperature influenced product formation. The major fermentation product from glycerol was n-butanol with a final concentration of up to 11.5 g/L. 3% (v/v) glycerol lead to a total solvent concentration of 14 g/L within 72 h. Growth was not inhibited by glycerol concentrations as high as 15% (v/v). The solventogenesis genes crt, bcd, etfA/B and hbd composing the bcs (butyryl-CoA synthesis) operon of C. tetanomorphum GT6 were sequenced. They occur in a genomic arrangement identical to those in other solventogenic clostridia. Furthermore, the sequence of a potential regulator gene highly similar to that of the NADH-sensing Rex family of regulatory genes was found upstream of the bcs operon. Potential binding sites for Rex have been identified in the promoter region of the bcs operon of solvent producing clostridia as well as upstream of other genes involved in NADH oxidation. This indicates a fundamental role of Rex in the regulation of fermentation products in anaerobic, and especially in solventogenic bacteria. Copyright © 2013 Elsevier GmbH. All rights reserved.

  19. Glucose screening tests during pregnancy

    Science.gov (United States)

    Oral glucose tolerance test - pregnancy; OGTT - pregnancy; Glucose challenge test - pregnancy; Gestational diabetes - glucose screening ... During the first step, you will have a glucose screening test: You DO NOT need to prepare ...

  20. Supplemental feeding with glycerol or propylene glycol of dairy cows in early lactation - Effects on metabolic status, body condition, and milk yield

    DEFF Research Database (Denmark)

    Lomander, H; Frössling, J; Ingvartsen, Klaus Lønne

    2012-01-01

    The objective of this field study was to evaluate the effect of supplemental feeding with glycerol or propylene glycol to dairy cows in early lactation on metabolic status, body condition and milk yield. In total, 673 newly calved cows from 12 commercial Swedish dairy herds were randomized to daily...... score (BCS) and heart girth (HG) were obtained at approximately 2 and 5 wk pp and at time of first insemination. The effects of supplemental feeding with GLY or PG on the plasma concentrations of glucose, NEFA, BHBA, insulin, and IGF-1, and BCS, HG, and occurrence of disease were analyzed....... No differences in BCS or HG or in plasma concentrations of glucose, BHBA, NEFA, or IGF-1 were found between the control group and any of the treatment groups. Cows in the GLY group had lower plasma insulin concentrations during DIM 0 to 63 compared with group CON, but no difference in insulin was found between...

  1. Penggunaan H-Zeolit dan Tawas dalam Pemurnian Crude Glycerol dengan Proses Adsorpsi dan Koagulasi

    Directory of Open Access Journals (Sweden)

    Isalmi Aziz, M.T

    2017-05-01

    Full Text Available Production of biodiesel from used cooking oil byproducts such as crude glycerol with low purity. The crude glycerol containing compounds impurities such as free fatty acids, alcohol, soap, catalyst and water. Compound adsorption of impurities can be done with the H-zeolite as adsorbent, but the resulting quality is still not good. To improve its quality, this research was added alum (coagulation process so that the adsorption of colloidal-sized compound impurities which can be separated from the glycerol. The purpose of this research is determine optimal condition of adsorption and coagulation impurity compounds of crude glycerol by using H-zeolite and  alum and  also determine quality of glycerol  was obtained. First, crude glycerol acidified by phosphoric acid 85% (pure analysis until desired pH ±2.5. It was obtained purity of glycerol 72.797%. The next process is adsorption with activated H-zeolite and it obtained purity of glycerol 77.079%. The last process in this research is adsorption and coagulation by using H-zeolite and alum. The highest purity glycerol 93.803% was obtained from condition of adsorption and coagulation for 75 minutes; alum’s concentration 80 ppm; and temperature 60 ºC. The glycerol discharged from adsorption and coagulation process by using H-zeolite and alum is qualify Indonesia National Standard number 06-1564-1995 with 3.512% water content; 2.438% ash content; 0.247% MONG content; has no sugar; 1.259 g/mL density of glycerol; 0.2356% potassium content and 0.0410% aluminium content; and brighter color.DOI: http://dx.doi.org/10.15408/jkv.v0i0.5143

  2. Sustaining Biodiesel Production via Value-Added Applications of Glycerol

    Directory of Open Access Journals (Sweden)

    Omotola Babajide

    2013-01-01

    Full Text Available The production of biofuels worldwide has been significant lately due to the shift from obtaining energy from nonrenewable energy (fossil fuels to renewable sources (biofuels. This energy shift arose as a result of the disturbing crude petroleum price fluctuations, uncertainties about fossil fuel reserves, and greenhouse gas (GHG concerns. With the production of biofuels increasing considerably and the current global biodiesel production from different feedstock, reaching about 6 billion liters per year, biodiesel production costs have been highly dependent on feedstock prices, ranging from 70 to 25; of total production costs, and in comparison with the conventional diesel fuel, the biodiesel is currently noncompetitive. An efficient production process is, therefore, crucial to lowering biodiesel production costs. The question of sustainability, however, arises, taking into account the African diverse conditions and how vital concerns need to be addressed. The major concern about biodiesel production costs can be reduced by finding value-added applications for its glycerol byproduct. This paper, thus, provides an overview of current research trends that could overcome the major hurdles towards profitable commercialization of biodiesel and also proposes areas of opportunity probable to capitalize the surplus glycerol obtained, for numerous applications.

  3. Crystal structure of substrate free form of glycerol dehydratase

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Der-Ing; Dotson, Garry; Turner, Jr., Ivan; Reiss, Lisa; Emptage, Mark (Du Pont)

    2010-03-08

    Glycerol dehydratase (GDH) and diol dehydratase (DDH) are highly homologous isofunctional enzymes that catalyze the elimination of water from glycerol and 1,2-propanediol (1,2-PD) to the corresponding aldehyde via a coenzyme B{sub 12}-dependent radical mechanism. The crystal structure of substrate free form of GDH in complex with cobalamin and K{sup +} has been determined at 2.5 {angstrom} resolution. Its overall fold and the subunit assembly closely resemble those of DDH. Comparison of this structure and the DDH structure, available only in substrate bound form, shows the expected change of the coordination of the essential K{sup +} from hexacoordinate to heptacoordinate with the displacement of a single coordinated water by the substrate diol. In addition, there appears to be an increase in the rigidity of the K{sup +} coordination (as measured by lower B values) upon the binding of the substrate. Structural analysis of the locations of conserved residues among various GDH and DDH sequences has aided in identification of residues potentially important for substrate preference or specificity of protein-protein interactions.

  4. Glycerol Production and Transformation: A Critical Review with Particular Emphasis on Glycerol Reforming Reaction for Producing Hydrogen in Conventional and Membrane Reactors.

    Science.gov (United States)

    Bagnato, Giuseppe; Iulianelli, Adolfo; Sanna, Aimaro; Basile, Angelo

    2017-03-23

    Glycerol represents an emerging renewable bio-derived feedstock, which could be used as a source for producing hydrogen through steam reforming reaction. In this review, the state-of-the-art about glycerol production processes is reviewed, with particular focus on glycerol reforming reactions and on the main catalysts under development. Furthermore, the use of membrane catalytic reactors instead of conventional reactors for steam reforming is discussed. Finally, the review describes the utilization of the Pd-based membrane reactor technology, pointing out the ability of these alternative fuel processors to simultaneously extract high purity hydrogen and enhance the whole performances of the reaction system in terms of glycerol conversion and hydrogen yield.

  5. New recombinant bacterium comprises a heterologous gene encoding glycerol dehydrogenase and/or an up-regulated native gene encoding glycerol dehydrogenase, useful for producing ethanol

    DEFF Research Database (Denmark)

    2010-01-01

    TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preparation (claimed): Producing recombinant bacterium having enhanced ethanol production characteristics when cultivated in growth medium comprising glycerol comprises: (a) transforming a parental bacterium by (i) the insertion of a heterologous gene encoding...

  6. Trace glucose and lipid metabolism in high androgen and high-fat diet induced polycystic ovary syndrome rats

    Directory of Open Access Journals (Sweden)

    Zhai Hua-Ling

    2012-01-01

    Full Text Available Abstract Background There is a high prevalence of diabetes mellitus (DM and dyslipidemia in women with polycystic ovary syndrome (PCOS. The purpose of this study was to investigate the role of different metabolic pathways in the development of diabetes mellitus in high-androgen female mice fed with a high-fat diet. Methods Female Sprague-Dawley rats were divided into 3 groups: the control group(C, n = 10; the andronate-treated group (Andronate, n = 10 (treated with andronate, 1 mg/100 g body weight/day for 8 weeks; and the andronate-treated and high-fat diet group (Andronate+HFD, n = 10. The rate of glucose appearance (Ra of glucose, gluconeogenesis (GNG, and the rate of glycerol appearance (Ra of glycerol were assessed with a stable isotope tracer. The serum sex hormone levels, insulin levels, glucose concentration, and the lipid profile were also measured. Results Compared with control group, both andronate-treated groups exhibited obesity with higher insulin concentrations (P P Conclusions Andronate with HFD rat model showed ovarian and metabolic features of PCOS, significant increase in glucose Ra, GNG, and lipid profiles, as well as normal blood glucose levels. Therefore, aberrant IR, increased glucose Ra, GNG, and lipid metabolism may represent the early-stage of glucose and lipid kinetics disorder, thereby might be used as potential early-stage treatment targets for PCOS.

  7. The new functions of the gut in the control of glucose homeostasis.

    Science.gov (United States)

    Mithieux, Gilles

    2005-07-01

    It has become clear during the past few years that the intestine is more than a digestive tract. In addition to its role as a subtle endocrine organ, its participation in endogenous glucose production, a property so far believed to be restricted to the liver and kidney, has been emphasized. The role of the gut in the regulation of glucose homeostasis has received further experimental accreditation from both animal and human studies. In relation to the molecular mechanisms of control of glucose production the potential regulatory role of glutaminase and glycerokinase has been suggested from studies of fasting, and the transcription of the glucose-6 phosphatase gene has been specified in an intestinal context. Furthermore, two newly described metabolic pathways accounting for the transepithelial transport of glucose have received further support: from the intestinal lumen to inside the enterocyte, involving a translocation of the glucose transporter Glut2 to the apical membrane, and from inside the enterocyte into the blood, involving glucose 6-phosphatase and independent of Glut2. The new knowledge regarding the control of glucose, glutamine, and glycerol metabolisms in the small intestine should be of interest to those who care for diabetic or septic patients, or are involved in nutrition research in humans. They should also be of importance in the knowledge of inherited genetic deficiencies, such as glycogen storage disease type 1 (Von Gierke disease) and the Fanconi-Bickel and glucose-galactose malabsorption syndromes.

  8. Metabolic engineering of a glycerol-oxidative pathway in Lactobacillus panis PM1 for utilization of bioethanol thin stillage: potential to produce platform chemicals from glycerol.

    Science.gov (United States)

    Kang, Tae Sun; Korber, Darren R; Tanaka, Takuji

    2014-12-01

    Lactobacillus panis PM1 has the ability to produce 1,3-propanediol (1,3-PDO) from thin stillage (TS), which is the major waste material after bioethanol production, and is therefore of significance. However, the fact that L. panis PM1 cannot use glycerol as a sole carbon source presents a considerable problem in terms of utilization of this strain in a wide range of industrial applications. Accordingly, L. panis PM1 was genetically engineered to directly utilize TS as a fermentable substrate for the production of valuable platform chemicals without the need for exogenous nutrient supplementation (e.g., sugars and nitrogen sources). An artificial glycerol-oxidative pathway, comprised of glycerol facilitator, glycerol kinase, glycerol 3-phosphate dehydrogenase, triosephosphate isomerase, and NADPH-dependent aldehyde reductase genes of Escherichia coli, was introduced into L. panis PM1 in order to directly utilize glycerol for the production of energy for growth and value-added chemicals. A pH 6.5 culture converted glycerol to mainly lactic acid (85.43 mM), whereas a significant amount of 1,3-propanediol (59.96 mM) was formed at pH 7.5. Regardless of the pH, ethanol (82.16 to 83.22 mM) was produced from TS fermentations, confirming that the artificial pathway metabolized glycerol for energy production and converted it into lactic acid or 1,3-PDO and ethanol in a pH-dependent manner. This study demonstrates the cost-effective conversion of TS to value-added chemicals by the engineered PM1 strain cultured under industrial conditions. Thus, application of this strain or these research findings can contribute to reduced costs of bioethanol production. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  9. Nano-structured Platinum-based Catalysts for the Complete Oxidation of Ethylene Glycol and Glycerol

    Science.gov (United States)

    Falase, Akinbayowa

    Direct alcohol fuel cells are a viable alternative to the traditional hydrogen PEM fuel cell. Fuel versatility, integration with existing distribution networks, and increased safety when handling these fuels increases their appeal for portable power applications. In order to maximize their utility, the liquid fuel must be fully oxidized to CO2 so as to harvest the full amount of energy. Methanol and ethanol are widely researched as potential fuels to power these devices, but methanol is a toxic substance, and ethanol has a much lower energy density than other liquids such as gasoline or glucose. Oxidation of complex fuels is difficult to realize, due to difficulty in breaking carbon-carbon bonding and poisoning of the catalysts by oxidative byproducts. In order to achieve the highest efficiency, an anode needs to be engineered in such a way as to maximize activity while minimizing poisoning effects of reaction byproducts. We have engineered an anode that uses platinum-based catalysts that is capable of completely oxidizing ethylene glycol and glycerol in neutral and alkaline media with little evidence of CO poisoning. We have constructed a hybrid anode consisting of a nano-structured PtRu electrocatayst with an NAD-dependent alcohol dehydrogenase for improved oxidation of complex molecules. A nano-structured PtRu catalyst was used to oxidize ethylene glycol and glycerol in neutral media. In situ infrared spectroscopy was used to verify complete oxidation via CO2 generation. There was no evidence of poisoning by CO species. A pH study was performed to determine the effect of pH on oxidative current. The peak currents did not trend at 60 mV/pH unit as would be expected from the Nernst equation, suggesting that adsorption of fuel to the surface of the electrode is not an electron-transfer step. We synthesized nano-structured PtRu, PtSn, and PtRuSn catalysts for oxidation of ethylene glycol and glycerol in alkaline media. The PtRu electrocatalyst the highest oxidative

  10. Synthesis of biodiesel fuel additives from glycerol using green chemistry and supercritical fluids

    Science.gov (United States)

    For every 3 moles of fatty acid esters produced, 1 mole of glycerol remains, ~11% of the biodiesel volume. One new method of glycerol use could be as a biodiesel fuel additive/extender using eco-friendly heterogeneous catalysts and supercritical fluids (SFs). SFs have advantages such as greater diff...

  11. Preliminary assessment of synthesis gas production via hybrid steam reforming of methane and glycerol

    NARCIS (Netherlands)

    Balegedde Ramachandran, P.; van Rossum, G.; Kersten, Sascha R.A.; van Swaaij, Willibrordus Petrus Maria

    2012-01-01

    In this article, hybrid steam reforming (HSR) of desulphurized methane, together with crude glycerol, in existing commercial steam reformers to produce synthesis gas is proposed. The proposed concept consists of a gasifier to produce vapors, gases, and char from crude glycerol, which is coupled with

  12. Bench scale demonstration of the Supermethanol concept : The synthesis of methanol from glycerol derived syngas

    NARCIS (Netherlands)

    van Bennekom, J. G.; Venderbosch, R. H.; Assink, D.; Lemmens, K. P. J.; Heeres, H. J.

    2012-01-01

    An integrated process for the synthesis of methanol from aqueous glycerol involving reforming of the feed to syngas followed by methanol synthesis is successfully demonstrated in a continuous bench scale unit. Glycerol reforming was carried out at pressures of 24-27 MPa and temperatures of 948-998 K

  13. Probing spatial heterogeneity in supercooled glycerol and temporal heterogeneity with single-molecule FRET in polyprolines

    NARCIS (Netherlands)

    Xia, Ted

    2010-01-01

    This thesis presents two lines of research. On the one hand, we investigate heterogeneity in supercooled glycerol by means of rheometry, small-angle neutron scattering, and fluorescence imaging. We find from the rheological experiments that supercooled glycerol can behave like weak solids at

  14. Biodegradable Composites Based on Starch/EVOH/Glycerol Blends and Coconut Fibers

    Science.gov (United States)

    Unripe coconut fibers were used as fillers in a biodegradable polymer matrix of starch/Ethylene vinyl alcohol (EVOH)/glycerol. The effects of fiber content on the mechanical, thermal and structural properties were evaluated. The addition of coconut fiber into starch/EVOH/glycerol blends reduced the ...

  15. Conversion of Glycerol to 3-Hydroxypropanoic Acid by Genetically Engineered Bacillus subtilis

    DEFF Research Database (Denmark)

    Kalantari, Aida; Chen, Tao; Ji, Boyang

    2017-01-01

    of glycerol into 3-HP. Our recombinant B. subtilis strains overexpress the two-step heterologous pathway containing glycerol dehydratase and aldehyde dehydrogenase from K. pneumoniae. Genetic engineering, driven by in silico optimization, and optimization of cultivation conditions resulted in a 3-HP titer...

  16. Continuous production of glycerol by catalytic high pressure hydrogenolysis of sucrose

    NARCIS (Netherlands)

    van Ling, Gerrit; Driessen, Alfons J.; Piet, Arie C.; Vlugter, Jozef C.

    1970-01-01

    Several continuous reactor systems have been discussed for the catalytic high pressure hydrogenolysis of sucrose to glycerol. Theoretically and actually, continuous reactors lead to lower glycerol yields than in a batch process. Two continuous stirred tank reactors in cascade constitute a reasonable

  17. Bacterial glycerol oxidation coupled to sulfate reduction at neutral and acidic pH.

    Science.gov (United States)

    Santos, Sidnei C; Liebensteiner, Martin G; van Gelder, Antonie H; Dimitrov, Mauricio R; Almeida, Paulo F; Quintella, Cristina M; Stams, Alfons J M; Sánchez-Andrea, Irene

    2018-03-27

    Glycerol is a main co-product of biodiesel production. Crude glycerol may serve as a cheap and attractive substrate in biotechnological applications, e.g. for the production of valuable chemicals or as an electron donor for reduction processes. In this work, sulfate reduction with glycerol was studied at neutral and acidic pH using bioreactor sludge samples and Tinto River sediments as a source of inoculum, respectively. Communities of sulfate-reducing bacteria (SRB) and fermentative bacteria were co-enriched at both pH values. Molecular analyses revealed that sequences belonging to Desulfomicrobium genus were dominant in the cultures enriched at pH 7, while Desulfosporosinus sequences dominated in the culture enriched at pH 4. Glycerol conversion was coupled to sulfate reduction, but the substrate was incompletely oxidized to acetate in the neutrophilic enrichments, and acetate, lactate, and 1,3-propanediol under low pH conditions. Two strains belonging to Desulfomicrobium and Proteiniphilum genera were isolated from the neutrophilic enrichments, but the first isolate was not able to use glycerol, which suggests a syntrophic relationship between glycerol-degrading fermentative bacteria and SRB. A Clostridium strain able to grow with glycerol was isolated from the low pH enrichment. Our data indicate that glycerol promotes the growth of sulfate-reducing communities to form sulfide, which can be used to precipitate and recover heavy metals.

  18. Green synthesis of noble nanometals (Au, Pt, Pd) using glycerol under microwave irradiation conditions

    Science.gov (United States)

    A newer application of glycerol in the field of nanomaterials synthesis has been developed from both the economic and environmental points of view. Glycerol can act as a reducing agent for the fabrication of noble nanometals, such as Au, Pt, and Pd, under microwave irradiation. T...

  19. Degree of branching in hyperbranched poly(glycerol-co-diacid)s synthesized in toluene

    Science.gov (United States)

    Hyperbranched polymers were synthesized by using a Lewis acid (dibutyltin(IV)oxide) to catalyze the polycondensation of glycerol with either succinic acid (n (aliphatic chain length)=2), glutaric acid (n=3) or azelaic acid (n=7) in toluene. These are the first examples of diacid-glycerol hyperbranc...

  20. 21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.

    Science.gov (United States)

    2010-04-01

    ... propylene glycol. 172.850 Section 172.850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH... esters of glycerol and propylene glycol. The food additive lactylated fatty acid esters of glycerol and propylene glycol may be safely used in food in accordance with the following prescribed conditions: (a) The...

  1. Enhancing Biodiesel Production Using Green Glycerol-Enriched Calcium Oxide Catalyst : An Optimization Study

    NARCIS (Netherlands)

    Avhad, Mangesh R.; Gangurde, L.S.; Sánchez, Marcos; Bouaid, Abderrahim; Aracil, José; Martínez, Mercedes; Marchetti, Jorge M.

    2018-01-01

    The present article demonstrates a superior catalytic performance of glycerol-enriched calcium oxide for biodiesel production than other calcium-based counterparts. The proficiency of glycerol-enriched calcium oxide in catalyzing the methanolysis of crude Jatropha curcas oil containing high free

  2. Co-digestion of sewage sludge with glycerol to boost biogas production.

    Science.gov (United States)

    Fountoulakis, M S; Petousi, I; Manios, T

    2010-10-01

    The feasibility of adding crude glycerol from the biodiesel industry to the anaerobic digesters treating sewage sludge in wastewater treatment plants was studied in both batch and continuous experiments at 35 degrees C. Glycerol addition can boost biogas yields, if it does not exceed a limiting 1% (v/v) concentration in the feed. Any further increase of glycerol causes a high imbalance in the anaerobic digestion process. The reactor treating the sewage sludge produced 1106+/-36 ml CH(4)/d before the addition of glycerol and 2353+/-94 ml CH(4)/d after the addition of glycerol (1% v/v in the feed). The extra glycerol-COD added to the feed did not have a negative effect on reactor performance, but seemed to increase the active biomass (volatile solids) concentration in the system. Batch kinetic experiments showed that the maximum specific utilization rate (mu(max)) and the saturation constant (K(S)) of glycerol were 0.149+/-0.015 h(-1) and 0.276+/-0.095 g/l, respectively. Comparing the estimated values with the kinetics constants for propionate reported in the literature, it can be concluded that glycerol uptake is not the rate-limiting step during the process. (c) 2010 Elsevier Ltd. All rights reserved.

  3. Enhancing effect of glycerol on the tensile properties of Bombyx mori cocoon sericin films.

    Science.gov (United States)

    Zhang, Haiping; Deng, Lianxia; Yang, Mingying; Min, Sijia; Yang, Lei; Zhu, Liangjun

    2011-01-01

    An environmental physical method described herein was developed to improve the tensile properties of Bombyx mori cocoon sericin films, by using the plasticizer of glycerol, which has a nontoxic effect compared with other chemical crosslinkers. The changes in the tensile characteristics and the structure of glycerolated (0-40 wt% of glycerol) sericin films were investigated. Sericin films, both in dry and wet states, showed enhanced tensile properties, which might be regulated by the addition of different concentrations of glycerol. The introduction of glycerol results in the higher amorphous structure in sericin films as evidenced by analysis of attenuated total reflection Fourier transform infrared (ATR-FTIR) spectra, thermogravimetry (TGA) and differential scanning calorimetry (DSC) curves. Scanning Electron Microscopy (SEM) observation revealed that glycerol was homogeneously blended with sericin molecules when its content was 10 wt%, while a small amount of redundant glycerol emerged on the surface of sericin films when its content was increased to 20 wt% or higher. Our results suggest that the introduction of glycerol is a novel nontoxic strategy which can improve the mechanical features of sericin-based materials and subsequently promote the feasibility of its application in tissue engineering.

  4. Enhancing Effect of Glycerol on the Tensile Properties of Bombyx mori Cocoon Sericin Films

    Directory of Open Access Journals (Sweden)

    Liangjun Zhu

    2011-05-01

    Full Text Available An environmental physical method described herein was developed to improve the tensile properties of Bombyx mori cocoon sericin films, by using the plasticizer of glycerol, which has a nontoxic effect compared with other chemical crosslinkers. The changes in the tensile characteristics and the structure of glycerolated (0–40 wt% of glycerol sericin films were investigated. Sericin films, both in dry and wet states, showed enhanced tensile properties, which might be regulated by the addition of different concentrations of glycerol. The introduction of glycerol results in the higher amorphous structure in sericin films as evidenced by analysis of attenuated total reflection Fourier transform infrared (ATR-FTIR spectra, thermogravimetry (TGA and differential scanning calorimetry (DSC curves. Scanning Electron Microscopy (SEM observation revealed that glycerol was homogeneously blended with sericin molecules when its content was 10 wt%, while a small amount of redundant glycerol emerged on the surface of sericin films when its content was increased to 20 wt% or higher. Our results suggest that the introduction of glycerol is a novel nontoxic strategy which can improve the mechanical features of sericin-based materials and subsequently promote the feasibility of its application in tissue engineering.

  5. Separation of oily sludge and glycerol from biodiesel processing waste by coagulation

    Directory of Open Access Journals (Sweden)

    Qiao-guang Xie1,

    2011-12-01

    Full Text Available Raw waste glycerol is a by-product of biodiesel production from transesterification, which is high in salt, and has a highpH value (more than 9.6. The purpose of this research is to reduce the water pollution from waste glycerol by using acoagulation process and discussing the possibility of waste glycerol reuse. The commercial coagulant (2% by weight, whichwas composed by cationic polyamine (PA 6% and poly-aluminium chloride (PACl 94% (w/w, was used as coagulant totreat waste glycerol. The results showed that after acidification and coagulation process, most of the chemical oxygen demand(COD, biochemical oxygen demand (BOD5, total suspended solids (TSS, and oily sludge (such as fatty acid, methyl ester,methanol and soap in raw waste glycerol were removed, except glycerol. The removal efficiencies of COD, BOD5, TSS, soapand methanol were 96.2%, 93.3%, 98.1%, 100%, and 85.8%, respectively, but the removal efficiency of glycerol was only65.4%. There was still a certain amount of glycerol (about 147.5g/L in the solution, which is separated from oily sludge.

  6. Optimization for microwave-assisted direct liquefaction of bamboo residue in glycerol/methanol mixtures

    Science.gov (United States)

    Jiulong Xie; Jinqiu Qi; Chungyun Hse; Todd F. Shupe

    2015-01-01

    Bamboo residues were liquefied in a mixture of glycerol and methanol in the presence of sulfuric acid using microwave energy. We investigated the effects of liquefaction conditions, including glycerol/methanol ratio, liquefaction temperature, and reaction time on the conversion yield. The optimal liquefaction conditions were under the temperature of 120

  7. Surface modification of thin film composite reverse osmosis membrane by glycerol assisted oxidation with sodium hypochlorite

    Science.gov (United States)

    Raval, Hiren D.; Samnani, Mohit D.; Gauswami, Maulik V.

    2018-01-01

    Need for improvement in water flux of thin film composite (TFC) RO membrane has been appreciated by researchers world over and surface modification approach is found promising to achieve higher water flux and solute rejection. Thin film composite RO membrane was exposed to 2000 mg/l sodium hypochlorite solution with varying concentrations of glycerol ranging from 1 to 10%. It was found that there was a drop in concentration of sodium hypochlorite after the addition of glycerol because of a new compound resulted from the oxidation of glycerol with sodium hypochlorite. The water flux of the membrane treated with 1% glycerol with 2000 mg/l sodium hypochlorite for 1 h was about 22% more and salt rejection was 1.36% greater than that of only sodium hypochlorite treated membrane for the same concentration and time. There was an increase in salt rejection of membrane with increase in concentration of glycerol from 1% to 5%, however, increasing glycerol concentration further up to 10%, the salt rejection declined. The water flux was found declining from 1% glycerol solution to 10% glycerol solution. The membrane samples were characterized to understand the change in chemical structure and morphology of the membrane.

  8. Effect of Glycerol Pretreatment on Levoglucosan Production from Corncobs by Fast Pyrolysis

    Directory of Open Access Journals (Sweden)

    Liqun Jiang

    2017-11-01

    Full Text Available In this manuscript, glycerol was used in corncobs’ pretreatment to promote levoglucosan production by fast pyrolysis first and then was further utilized as raw material for chemicals production by microbial fermentation. The effects of glycerol pretreatment temperatures (220–240 °C, time (0.5–3 h and solid-to-liquid ratios (5–20% were investigated. Due to the accumulation of crystalline cellulose and the removal of minerals, the levoglucosan yield was as high as 35.8% from corncobs pretreated by glycerol at 240 for 3 h with a 5% solid-to-liquid ratio, which was obviously higher than that of the control (2.2%. After glycerol pretreatment, the fermentability of the recovered glycerol remaining in the liquid stream from glycerol pretreatment was evaluated by Klebsiella pneumoniae. The results showed that the recovered glycerol had no inhibitory effect on the growth and metabolism of the microbe, which was a promising substrate for fermentation. The value-added applications of glycerol could reduce the cost of biomass pretreatment. Correspondingly, this manuscript offers a green, sustainable, efficient and economic strategy for an integrated biorefinery process.

  9. Study of combined effects of glycerol and transglutaminase on properties of gelatin films

    Science.gov (United States)

    Gelatin films plasticized with different glycerol contents (0-40%) were cross-linked using transglutaminase (TGase). Unmodified films were prepared as controls. Cross-linking degree of the films decreased linearly with increasing glycerol content, resulting in an increase in water solubility. Glycer...

  10. Lipopolysaccharide Modifies Glycerol Permeability and Metabolism in 3T3-L1 Adipocytes

    Directory of Open Access Journals (Sweden)

    Jeanne Durendale Chiadak

    2017-11-01

    Full Text Available Aquaglyceroporins—aquaporin membrane channels (AQP that conduct glycerol and other small neutral solutes in addition to water—play major roles in obesity. In adipocytes, aquaglyceroporins mediate glycerol uptake and release across the plasma membrane, which are two key steps for triacylglycerols (TAGs synthesis (lipogenesis and hydrolysis (lipolysis. The aim of this study was to assess both glycerol permeability and metabolism in undifferentiated 3T3-L1 cells (UDCs as well as in untreated (CTL-DCs versus lipopolysaccharide (LPS-DCs-treated differentiated 3T3-L1 adipocytes. Glycerol release, TAGs content and whole membrane glycerol permeability were significantly increased in DCs as compared to UDCs. Moreover, in DCs, LPS treatment significantly increased TAGs content and decreased glycerol permeability. In addition, a significant reduction in whole membrane glycerol permeability was observed in LPS-DCs as compared to CTL-DCs. The relative contributions of AQP3, AQP7 and AQP9 (facilitated diffusion, as well as that of the phospholipid bilayer (simple diffusion, to the whole membrane glycerol permeability, were estimated biophysically in UDCs, CTL-DCs and LPS-DCs, using selective AQP inhibitors. Further studies will be required to determine if modifications in either subcellular localization and/or activity of aquaglyceroporins could account for the data herein. Nevertheless, our findings provide novel insights in understanding the LPS-induced adipocyte hypertrophy that accompanies obesity.

  11. Production of 1,3-propanediol from glycerol by engineered using a ...

    African Journals Online (AJOL)

    1,3-Propanediol (1,3-PD) has versatile applications in polymers, cosmetics, foods and medicines. In order to consolidate the functions of glycerol dehydratase gene dhaB and 1,3-propanediol oxidoreductase gene dhaT and produce 1,3-PD from glycerol, the genes dhaB and dhaT from Klebsiella pneumoniae were inserted ...

  12. Kinetic analysis of a Saccharomyces cerevisiae strain adapted for improved growth on glycerol: Implications for the development of yeast bioprocesses on glycerol.

    Science.gov (United States)

    Ochoa-Estopier, A; Lesage, J; Gorret, N; Guillouet, S E

    2011-01-01

    Glycerol is an agro-industrial residue generated in high amounts during the biodiesel production. The growing production of biodiesel is creating a worldwide glycerol surplus. Therefore, replacing sugar-based feedstock in bioprocesses by glycerol could be potentially attractive. Saccharomyces cerevisiae is one of the most commonly used microorganisms in the agri-food industry and therefore currently produced in large quantities from sugar-based feedstock. Unfortunately, growth of S. cerevisiae strains on glycerol is very low with reported μmax around 0.01 h(-1). This study demonstrates that successive growth of the S. cerevisiae CBS 8066, CEN.PK 113-7 D and Ethanol Red on glycerol as sole carbon source considerably improved the μmax from 0.01 up to 0.2 h(-1). The "adapted strain" CBS 8066-FL20 was kinetically characterized during aerobic and oxygen-limited cultivation in bioreactor and the results discussed in terms of their implication for developing glycerol-based S. cerevisiae bioprocesses. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Distribution of coenzyme B12-dependent diol dehydratase and glycerol dehydratase in selected genera of Enterobacteriaceae and Propionibacteriaceae.

    Science.gov (United States)

    Toraya, T; Kuno, S; Fukui, S

    1980-03-01

    The presence of diol dehydratase and glycerol dehydratase was shown in several bacteria of Enterobacteriaceae grown anaerobically on 1,2-propanediol and on glycerol, respectively. Diol dehydratases of Enterobacteriaceae were immunologically similar, but distinct from that of Propionibacterium freudenreichii.

  14. In situ visualization and effect of glycerol in lipase-catalyzed ethanolysis of rapeseed oil

    DEFF Research Database (Denmark)

    Xu, Yuan; Nordblad, Mathias; Nielsen, Per M.

    2011-01-01

    Immobilized lipases can be used in biodiesel production to overcome many disadvantages of the conventional base-catalyzed process. However, the glycerol by-product poses a potential problem for the biocatalytic process as it is known to inhibit immobilized lipases, most likely by clogging...... of the catalyst particles. In this paper, this negative effect was further investigated and confirmed in ethanolysis of rapeseed oil. A dyeing method was developed for in situ visualization of glycerol in order to study its partitioning and accumulation during the ethanolysis reaction. The method was used...... to illustrate the interaction of glycerol with immobilized lipases and thus provided an aid for screening supports for lipase immobilization according to their interaction with glycerol. Glycerol was found to have great affinity for silica, less for polystyrene and no affinity for supports made from...

  15. Human skeletal muscle fatty acid and glycerol metabolism during rest, exercise and recovery

    DEFF Research Database (Denmark)

    Van Hall, Gerrit; Sacchetti, M; Rådegran, G

    2002-01-01

    This study was conducted to investigate skeletal muscle fatty acid (FA) and glycerol kinetics and to determine the contribution of skeletal muscle to whole body FA and glycerol turnover during rest, 2 h of one-leg knee-extensor exercise at 65 % of maximal leg power output, and 3 h of recovery....... To this aim, the leg femoral arterial-venous difference technique was used in combination with a continuous infusion of [U-(13)C]palmitate and [(2)H(5)]glycerol in five post-absorptive healthy volunteers (22 +/- 3 years). The influence of contamination from non-skeletal muscle tissues, skin and subcutaneous...... adipose tissue, on FA and glycerol kinetics was studied by catheterization of the femoral vein in antegrade and retrograde directions. Substantially higher net leg FA and glycerol uptakes were observed with a retrograde compared to an antegrade catheter position, as a result of a much lower tracer...

  16. Performance of a direct glycerol fuel cell using KOH doped polybenzimidazole as electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Ana P.; Linares, Jose J., E-mail: joselinares@unb.br [Universidade de Brasilia (UnB), Brasilia, DF (Brazil). Instituto de Quimica

    2014-03-15

    This paper studies the influence of the operating variables (glycerol concentration, temperature and feed rate) for a direct glycerol fuel cell fed with glycerol using polybenzimidazole (PBI) impregnated with KOH as electrolyte and Pt/C as catalyst. Temperature displays a beneficial effect up to 75 °C due to the enhanced conductivity and kinetics of the electrochemical reactions. The optimum cell feed corresponds to 1 mol L{sup -1} glycerol and 4 mol L{sup -1} KOH, supplying sufficient quantities of fuel and electrolyte without massive crossover nor mass transfer limitations. The feed rate increases the performance up to a limit of 2 mL min{sup -1}, high enough to guarantee the access of the glycerol and the exit of the products. Finally, the use of binary catalysts (PtRu/C and Pt{sub 3}Sn/C) is beneficial for increasing the cell performance. (author)

  17. Performance of a direct glycerol fuel cell using KOH doped polybenzimidazole as electrolyte

    International Nuclear Information System (INIS)

    Nascimento, Ana P.; Linares, Jose J.

    2014-01-01

    This paper studies the influence of the operating variables (glycerol concentration, temperature and feed rate) for a direct glycerol fuel cell fed with glycerol using polybenzimidazole (PBI) impregnated with KOH as electrolyte and Pt/C as catalyst. Temperature displays a beneficial effect up to 75 °C due to the enhanced conductivity and kinetics of the electrochemical reactions. The optimum cell feed corresponds to 1 mol L -1 glycerol and 4 mol L -1 KOH, supplying sufficient quantities of fuel and electrolyte without massive crossover nor mass transfer limitations. The feed rate increases the performance up to a limit of 2 mL min -1 , high enough to guarantee the access of the glycerol and the exit of the products. Finally, the use of binary catalysts (PtRu/C and Pt 3 Sn/C) is beneficial for increasing the cell performance. (author)

  18. Navigating Glycerol Conversion Roadmap and Heterogeneous Catalyst Selection Aided by Density Functional Theory: A Review

    Directory of Open Access Journals (Sweden)

    Bin Liu

    2018-01-01

    Full Text Available Glycerol has been utilized in an extremely diversified manner throughout human civilization—ranging from food, to various consumer products, to pharmaceuticals, and even explosives. Large surplus in glycerol supply thanks to biodiesel production and biomass processing has created a demand to further boost its utility. One growing area is to expand the use of glycerol as an alternative feedstock to supplement fuels and chemicals production. Various catalytic processes have been developed. This review summarizes catalytic materials for glycerol reforming, hydrodeoxygenation, and oxidation. In particular, rationale for catalyst selection and new catalyst design will be discussed aided by the knowledge of reaction mechanisms. The role of theoretical density functional theory (DFT in elucidating complex glycerol conversion chemistries is particularly emphasized.

  19. Anaerobic and aerobic batch cultivations of Saccharomyces cerevisiae mutants impaired in glycerol synthesis

    DEFF Research Database (Denmark)

    Nissen, Torben Lauesgaard; Hamann, Claus Wendelboe; Kielland-Brandt, M. C.

    2000-01-01

    Glycerol is formed as a by-product in production of ethanol and baker's yeast during fermentation of Saccharomyces cerevisiae under anaerobic and aerobic growth conditions, respectively. One physiological role of glycerol formation by yeast is to reoxidize NADH, formed in synthesis of biomass...... and secondary fermentation products, to NAD(+). The objective of this study was to evaluate whether introduction of a new pathway for reoxidation of NADH, in a yeast strain where glycerol synthesis had been impaired, would result in elimination of glycerol production and lead to increased yields of ethanol...... and biomass under anaerobic and aerobic growth conditions, respectively. This was done by deletion of GPD1 and GPD2, encoding two isoenzymes of glycerol 3-phosphate dehydrogenase, and expression of a cytoplasmic transhydrogenase from Azotobacter vinelandii, encoded by cth. In anaerobic batch fermentations...

  20. Rheological properties of purified illite clays in glycerol/water suspensions

    Science.gov (United States)

    Dusenkova, I.; Malers, J.; Berzina-Cimdina, L.

    2015-04-01

    There are many studies about rheological properties of clay-water suspensions, but no published investigations about clay-glycerol suspensions. In this work apparent viscosity of previously purified illite containing clay fraction acids and other non-clay minerals were almost totally removed by centrifugation. All obtained suspensions behaved as shear-thinning fluids with multiple times higher viscosity than pure glycerol/water solutions. Reduction of clay fraction concentration by 5% decreased the apparent viscosity of 50% glycerol/water suspensions approximately 5 times. There was basically no difference in apparent viscosity between all four 50% glycerol/water suspensions, but in 90% glycerol/water suspensions samples from Iecava deposit showed slightly higher apparent viscosity, which could be affected by the particle size distribution.

  1. Prior ingestion of exogenous ketone monoester attenuates the glycaemic response to an oral glucose tolerance test in healthy young individuals.

    Science.gov (United States)

    Myette-Côté, Étienne; Neudorf, Helena; Rafiei, Hossein; Clarke, Kieran; Little, Jonathan Peter

    2018-02-15

    The recent development of exogenous ketone supplements allows direct testing of the metabolic effects of elevated blood ketones without the confounding influence of widespread changes experienced with ketogenic diets or prolonged fasting. In the present study, we determined the effect of (R)-3-hydroxybutyl (R)-3-hydroxybutyrate ketone monoester on the glycaemic response and insulin sensitivity index during a 2 h oral glucose tolerance test (OGTT) in humans. The results obtained show that consuming a ketone monoester supplement 30 min prior to an OGTT reduced the glycaemic response and markers of insulin sensitivity without affecting insulin secretion. The findings of the present study provides evidence that ketone supplements could have therapeutic potential for future application as a glucose-lowering nutritional supplement. The main objectives of the present study were: (i) to determine whether acute ingestion of ketone monoester (K me ); (R)-3-hydroxybutyl (R)-3-hydroxybutyrate impacts plasma glucose levels during a standardized oral glucose tolerance test (OGTT) and (ii) to compare changes in insulin concentrations and estimates of insulin sensitivity after acute K me supplementation. Twenty healthy participants (n = 10 males/females) aged between 18 and 35 years took part in a randomized cross-over study. After an overnight fast, participants consumed a K me supplement (ΔG®; TΔS Ltd, UK, Oxford, UK; 0.45 ml kg -1 body weight) or placebo (water) 30 min before completing a 75 g OGTT. Blood samples were collected every 15-30 min over 2.5 h. The participants and study personnel performing the laboratory analyses were blinded to the study condition. K me acutely raised blood d-beta-hydroxybutyrate (β-OHB) to 3.2 ± 0.6 mm within 30 min with levels remaining elevated throughout the entire OGTT. Compared to placebo, K me significantly decreased the glucose area under the curve (AUC; -16%, P = 0.001), non-esterified fatty acid AUC (-44%, P < 0

  2. Measuring brain glucose phosphorylation with labeled glucose

    International Nuclear Information System (INIS)

    Brondsted, H.E.; Gjedde, A.

    1988-01-01

    This study tested whether glucose labeled at the C-6 position generates metabolites that leave brain so rapidly that C-6-labeled glucose cannot be used to measure brain glucose phosphorylation (CMRGlc). In pentobarbital-anesthetized rats, the parietal cortex uptake of [ 14 C]glucose labeled in the C-6 position was followed for times ranging from 10 s to 60 min. We subtracted the observed radioactivity from the radioactivity expected with no loss of labeled metabolites from brain by extrapolation of glucose uptake in an initial period when loss was negligible. The observed radioactivity was a monoexponentially declining function of the total radioactivity expected in the absence of metabolite loss. The constant of decline was 0.0077.min-1 for parietal cortex. Metabolites were lost from the beginning of the experiment. However, with correction for the loss of labeled metabolites, it was possible to determine an average CMRGlc between 4 and 60 min of circulation of 64 +/- 4 (SE; n = 49) mumol.hg-1.min-1

  3. Preparation and characterization of zinc glycerolate: UV protection, biological activity and permeation study

    Directory of Open Access Journals (Sweden)

    Mei Yee Cheong

    2017-09-01

    Full Text Available Zinc glycerolate, has been reported to be beneficial in the treatment of many medical ailments but its properties for skincare application are not explored. Zinc glycerolate has been successfully synthesized by heating zinc oxide and glycerol in 240 °C via microwave irradiation. The characterization and properties of zinc glycerolate were discussed including scanning electron microscopy (SEM, laser diffraction particle size analysis, in vitro irritancy potential, UV protection, antibacterial and permeation properties via Franz diffusion cell of the zinc glycerolate. Zinc glycerolate is classified as non-irritant when used in dermal application. It has SPF of 1.007 ± 0.004 and ultraviolet A to B (UVA/UVB ratio of 0.7 ± 0.019 which is considered good for UVA protection under Boot’s star rating. The antimicrobial properties of zinc glycerolate were expressed as the minimum inhibitory concentration (MIC; the minimum bactericidal concentration (MBC and the time needed to eliminate 99.9% of the bacteria population (time-kill. Zinc glycerolate has better bactericidal properties than zinc oxide particularly towards Staphylococcus epidermis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Propionibacterium acnes while no effect was observed for Candida albicans and Aspergillus niger. The concentration of zinc ions that has diffused through polysulfone membrane installed in a vertical diffusion cell was determined through atomic absorption spectroscopy (AAS. The highest concentration of zinc ion diffused was found from incorporation of zinc glycerolate in oil-in-water (O/W cream-based excipient. The obtained results indicated that zinc glycerolate has a good potential for applications in the cosmetics and pharmaceutical products.

  4. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Complications Neuropathy Foot Complications DKA (Ketoacidosis) & Ketones Kidney Disease (Nephropathy) Gastroparesis Mental Health Step On Up Treatment & Care Blood Glucose Testing ...

  5. Biostable glucose permeable polymer

    DEFF Research Database (Denmark)

    2017-01-01

    A new biostable glucose permeable polymer has been developed which is useful, for example, in implantable glucose sensors. This biostable glucose permeable polymer has a number of advantageous characteristics and, for example, does not undergo hydrolytic cleavage and degradation, thereby providing...... a composition that facilitates long term sensor stability in vivo. The versatile characteristics of this polymer allow it to be used in a variety of contexts, for example to form the body of an implantable glucose sensor. The invention includes the polymer composition, sensor systems formed from this polymer...

  6. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Complications Neuropathy Foot Complications DKA (Ketoacidosis) & Ketones Kidney Disease (Nephropathy) Gastroparesis Mental Health Step On Up Treatment & Care Blood Glucose Testing Medication Doctors, Nurses & More ...

  7. Use of biodiesel-derived crude glycerol for producing eicosapentaenoic acid (EPA) by the fungus pythium irregulare

    Science.gov (United States)

    Crude glycerol is a major byproduct for the biodiesel industry. Producing value-added products through microbial fermentation on crude glycerol provides opportunities to utilize a large quantity of this byproduct. The objective of this study is to explore the potential of using crude glycerol for ...

  8. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Your Carbs Count Glycemic Index Low-Calorie Sweeteners Sugar and Desserts Fitness Exercise & Type 1 Diabetes Get Started Safely Get And Stay Fit Types ... the following: High blood glucose High levels of sugar in the ... Part of managing your diabetes is checking your blood glucose often. Ask your ...

  9. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... by Mail Close www.diabetes.org > Living With Diabetes > Treatment and Care > Blood Glucose Testing Share: Print Page ... and-how-tos, . In this section Living With Diabetes Treatment and Care Blood Glucose Testing Checking Your Blood ...

  10. Blood Test: Glucose

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Blood Test: Glucose KidsHealth / For Parents / Blood Test: Glucose What's ... español Análisis de sangre: glucosa What Is a Blood Test? A blood test is when a sample of ...

  11. Studies on the production of glucose isomerase by Bacillus licheniformis

    Directory of Open Access Journals (Sweden)

    Nwokoro Ogbonnaya

    2015-09-01

    Full Text Available This work reports the effects of some culture conditions on the production of glucose isomerase by Bacillus licheniformis. The bacterium was selected based on the release of 3.62 mg/mL fructose from the fermentation of glucose. Enzyme was produced using a variety of carbon substrates but the highest enzyme activity was detected in a medium containing 0.5% xylose and 1% glycerol (specific activity = 6.88 U/mg protein. Media containing only xylose or glucose gave lower enzyme productivies (specific activities= 4.60 and 2.35 U/mg protein respectively. The effects of nitrogen substrates on glucose isomerase production showed that yeast extract supported maximum enzyme activity (specific activity = 5.24 U/mg protein. Lowest enzyme activity was observed with sodium trioxonitrate (specific activity = 2.44 U/mg protein. In general, organic nitrogen substrates supported higher enzyme productivity than inorganic nitrogen substrates. Best enzyme activity was observed in the presence of Mg2+ (specific activity = 6.85 U/mg protein while Hg2+ was inhibitory (specific activity = 1.02 U/mg protein. The optimum pH for best enzyme activity was 6.0 while optimum temperature for enzyme production was 50ºC.

  12. Nanomaterials in glucose sensing

    CERN Document Server

    Burugapalli, Krishna

    2013-01-01

    The smartness of nano-materials is attributed to their nanoscale and subsequently unique physicochemical properties and their use in glucose sensing has been aimed at improving performance, reducing cost and miniaturizing the sensor and its associated instrumentation. So far, portable (handheld) glucose analysers were introduced for hospital wards, emergency rooms and physicians' offices; single-use strip systems achieved nanolitre sampling for painless and accurate home glucose monitoring; advanced continuous monitoring devices having 2 to 7 days operating life are in clinical and home use; and continued research efforts are being made to develop and introduce increasingly advanced glucose monitoring systems for health as well as food, biotechnology, cell and tissue culture industries. Nanomaterials have touched every aspect of biosensor design and this chapter reviews their role in the development of advanced technologies for glucose sensing, and especially for diabetes. Research shows that overall, nanomat...

  13. Brain Glucose Metabolism Controls Hepatic Glucose and Lipid Production

    OpenAIRE

    Lam, Tony K.T.

    2007-01-01

    Brain glucose-sensing mechanisms are implicated in the regulation of feeding behavior and hypoglycemic-induced hormonal counter-regulation. This commentary discusses recent findings indicating that the brain senses glucose to regulate both hepatic glucose and lipid production.

  14. Physiologic Mechanisms Involved in Accumulation of 3-Hydroxypropionaldehyde during Fermentation of Glycerol by Enterobacter agglomerans.

    Science.gov (United States)

    Barbirato, F; Soucaille, P; Bories, A

    1996-12-01

    When grown in 700 mM glycerol within the pH range 6.0 to 7.5, anaerobic pH-regulated cultures of Enterobacter agglomerans exhibited an extracellular accumulation of 3-hydroxypropionaldehyde (3-HPA). This phenomenon, which causes fermentation cessation, occurred earlier when pH was low. In contrast, substrate consumption was complete at pH 8. Levels of glycerol-catabolizing enzymes, i.e., glycerol dehydrogenase and dihydroxyacetone kinase for the oxidative route and glycerol dehydratase and 1,3-propanediol dehydrogenase for the reductive route, as well as the nucleotide pools were determined periodically in the pH 7- and pH 8-regulated cultures. A NAD/NADH ratio of 1.7 was correlated with the beginning of the production of the inhibitory metabolite. Further accumulation was dependent on the ratio of glycerol dehydratase activity to 1,3-propanediol dehydrogenase activity. For a ratio higher than 1, 3-HPA was produced until fermentation ceased, which occurred for the pH 7-regulated culture. At pH 8, a value below 1 was noticed and 3-HPA accumulation was transient, while the NAD/NADH ratio decreased. The low rate of glycerol dissimilation following the appearance of 3-HPA in the culture medium was attributed to the strong inhibitory effect exerted by 3-HPA on glycerol dehydrogenase activity.

  15. Synthesis and Thermal-Stability Study of Polybutylene Itaconate Modified with Divinyl Benzene and Glycerol

    Directory of Open Access Journals (Sweden)

    Atmanto Heru Wibowo

    2014-10-01

    Full Text Available Polybutylene itaconate (PBI for modification with divinyl benzene (DVB and glycerol has been synthesized at 180 °C for 3 h via polycondensation of itaconic acid (IA and butanediols using catalyst of Ti(OBu4. Modification on PBI was done with addition of 15%, 20% and 25% DVB (w/w using benzoyl peroxide. With glycerol, weight variations of glycerol:1,4-butanediol (BDO in the synthesis were 10%, 30%, and 50% (mole/mole. PBI and PBI modified with DVB and glycerol were characterized with FTIR and TG-DTA. PBI showed a wavenumber shift from 1703 cm-1 to 1728 cm-1 of the C=O functional group from acid to esther. The DVB modification on PBI also showed that the intensity decrease of C=C stretching was due to the formation of crosslinking on the double bond. In the modification with glycerol, three dimensional networking on the polyester occurred through bonding between hydroxyl of glycerol and acid group of IA. Constant intensity of C=C stretching on polyester was seen. The thermal stability of PBI modified with DVB increased, accompanied by rigidity change of the structure. The thermal stability of PBI modified with glycerol decreased, caused by the decrease of regularity degree and the elasticity increase of the three dimensional structure of polyester.

  16. Glycerol, trehalose and glycerol–trehalose mixture effects on thermal stabilization of OCT

    Energy Technology Data Exchange (ETDEWEB)

    Barreca, D., E-mail: dbarreca@unime.it [Dipartimento di Scienze Chimiche, Università di Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina (Italy); Laganà, G. [Dipartimento di Scienze Chimiche, Università di Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina (Italy); Magazù, S.; Migliardo, F. [Dipartimento di Fisica, Università di Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina (Italy); Bellocco, E. [Dipartimento di Scienze Chimiche, Università di Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina (Italy)

    2013-10-16

    Highlights: • Trehalose influences both enzymatic activity and conformational changes of enzyme. • The results obtained by INS and QENS show a switching-off of the fast dynamics at very low glycerol content. • The diffusive dynamics is slowing down at very low glycerol concentration. • The mixtures of trehalose/glycerol lose the thermal stabilizing effects of pure compounds. - Abstract: The stabilization effects of trehalose, glycerol and their mixtures on ornithine carbamoyltransferase catalytic activity has been studied as a function of temperature by complementary techniques. The obtained results show that the kinematic viscosities of trehalose (1.0 M) and protein mixture are higher than the one of glycerol plus protein. Changing the trehalose/glycerol ratio, we notice a decrease of the kinematic viscosity values at almost all the analyzed ratio. In particular, the solution composed of 95% trehalose-5% glycerol shows a peculiar behavior. Moreover the trehalose (1.0 M) solution shows the higher OCT thermal stabilization at 343 K, while all the other solutions show minor effects. The smallest stabilizing effect is revealed for the solution that shows the maximum kinematic viscosity. These results support Inelastic Neutron Scattering (INS) and Quasi Elastic Neutron Scattering (QENS) findings, which pointed out a slowing down of the relaxation and diffusive dynamics in some investigated samples.

  17. Glycerol as a chemical chaperone enhances radiation-induced apoptosis in anaplastic thyroid carcinoma cells

    Directory of Open Access Journals (Sweden)

    Emoto Mie

    2002-10-01

    Full Text Available Abstract Introduction Anaplastic thyroid carcinoma, which is one of the most aggressive, malignant tumors in humans, results in an extremely poor prognosis despite chemotherapy and radiotherapy. The present study was designed to evaluate therapeutic effects of radiation by glycerol on p53-mutant anaplastic thyroid carcinoma cells (8305c cells. To examine the effectiveness of glycerol in radiation induced lethality for anaplastic thyroid carcinoma 8305c cells, we performed colony formation assay and apoptosis analysis. Results Apoptosis was analyzed with Hoechst 33342 staining and DNA ladder formation assay. 8305c cells became radiosensitive when glycerol was added to culture medium before X-ray irradiation. Apoptosis was induced by X-rays in the presence of glycerol. However, there was little apoptosis induced by X-ray irradiation or glycerol alone. The binding activity of whole cell extracts to bax promoter region was induced by X-rays in the presence of glycerol but not by X-rays alone. Conclusion These findings suggest that glycerol is effective against radiotherapy of p53-mutant thyroid carcinomas.

  18. Glycerol as a source of designer solvents: physicochemical properties of low melting mixtures containing glycerol ethers and ammonium salts.

    Science.gov (United States)

    Leal-Duaso, Alejandro; Pérez, Pascual; Mayoral, José A; Pires, Elisabet; García, José I

    2017-10-25

    In this work we report the preparation of mixtures of several alkyl glyceryl ethers, as hydrogen bond donor compounds, with two ammonium salts, choline chloride and N,N,N-triethyl-2,3-dihydroxypropan-1-aminium chloride. The stability of the mixtures at different molar ratios and temperatures has been evaluated in order to determine the formation of low melting mixtures. Liquid and stable mixtures have been characterized and their physico-chemical properties such as density, viscosity, refractive index, conductivity and surface tension have been measured in the temperature range of 293.15 K to 343.15 K. Comparison of the mixtures prepared herein with the ones containing glycerol and choline chloride evidences the possibility of tuning the physico-chemical properties by changing the substitution pattern in the hydrogen bond donor compound or in the ammonium salt, thus broadening the scope of application of these mixtures.

  19. Fermentative utilization of glycerol residue for the production of acetic acid

    Science.gov (United States)

    Irvan; Trisakti, B.; Hasibuan, R.; Joli, M.

    2018-02-01

    Glycerol residue, frequently known as pitch, is a waste produced from the downstream product of crude glycerine distillation. With the increasing need of pure glycerine in the world, the glycerol residue produced is also increasing. Glycerol residue is a solid waste at room temperature, highly alkaline (pH > 13), corrosive, and categorized as hazardous and poisonous waste. In this research, acetic acid was produced from glycerol residue through the anaerobic fermentation process by using purple non-sulphur photosynthetic bacteria. The purpose of this study was to find out the influence of concentration change of glycerol residue on time and to find out the possibility of glycerol residue to be utilized as acetic acid. In this research, at first 400 g of glycerol residue was diluted with 200 ml of distilled water to change the glycerine phase, from solid to liquid at room temperature, acidified by using hydrochloric acid until pH 2. The top layer formed was fatty acid and triglycerides that should be removed. Meanwhile, the bottom layer was diluted glycerol residue which was then neutralized with caustic soda. To produce acetic acid, glycerol residue with various concentrations, salt, and purple non-sulphur photosynthetic bacteria were put together into a 100 ml bottle which had been previously sterilized, then incubated for four weeks under the light of 40-watt bulb. The result showed that on the 28th day of fermentation, the produced acetic acid were 0.28, 1.85, and 0.2% (w/w) by using glycerine with the concentration of 0.5, 1.0, and 1.5% (w/w), respectively.

  20. Energy recovery from waste glycerol by utilizing thermal water vapor plasma.

    Science.gov (United States)

    Tamošiūnas, Andrius; Valatkevičius, Pranas; Gimžauskaitė, Dovilė; Jeguirim, Mejdi; Mėčius, Vladas; Aikas, Mindaugas

    2017-04-01

    Glycerol, considered as a waste feedstock resulting from biodiesel production, has received much attention in recent years due to its properties, which offer to recover energy. The aim of this study was to investigate the use of a thermal water vapor plasma for waste (crude) glycerol conversion to synthesis gas, or syngas (H 2  + CO). In parallel of crude glycerol, a pure glycerol (99.5%) was used as a reference material in order to compare the concentrations of the formed product gas. A direct current (DC) arc plasma torch stabilized by a mixture of argon/water vapor was utilized for the effective glycerol conversion to hydrogen-rich synthesis gas. It was found that after waste glycerol treatment, the main reaction products were gases with corresponding concentrations of H 2 50.7%, CO 23.53%, CO 2 11.45%, and CH 4 3.82%, and traces of C 2 H 2 and C 2 H 6 , which concentrations were below 0.5%. The comparable concentrations of the formed gas products were obtained after pure glycerol conversion-H 2 46.4%, CO 26.25%, CO 2 11.3%, and CH 4 4.7%. The use of thermal water vapor plasma producing synthesis gas is an effective method to recover energy from both crude and pure glycerol. The performance of the glycerol conversion system was defined in terms of the produced gas yield, the carbon conversion efficiency, the cold gas efficiency, and the specific energy requirements.