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Sample records for glycerol monolaurate prevents

  1. Glycerol Monolaurate Inhibits Lipase Production by Clinical Ocular Isolates Without Affecting Bacterial Cell Viability.

    Science.gov (United States)

    Flanagan, Judith Louise; Khandekar, Neeta; Zhu, Hua; Watanabe, Keizo; Markoulli, Maria; Flanagan, John Terence; Papas, Eric

    2016-02-01

    We sought to determine the relative lipase production of a range of ocular bacterial isolates and to assess the efficacy of glycerol monolaurate (GML) in inhibiting this lipase production in high lipase-producing bacteria without affecting bacterial cell growth. Staphylococcus aureus,Staphylococcus epidermidis,Propionibacterium acnes, and Corynebacterium spp. were inoculated at a density of 10(6)/mL in varying concentrations of GML up to 25 μg/mL for 24 hours at 37 °C with constant shaking. Bacterial suspensions were centrifuged, bacterial cell density was determined, and production of bacterial lipase was quantified using a commercial lipase assay kit. Staphylococcus spp. produced high levels of lipase activity compared with P. acnes and Corynebacterium spp. GML inhibited lipase production by Staphylococcal spp. in a dose-dependent manner, with S. epidermidis lipase production consistently more sensitive to GML than S. aureus. Glycerol monolaurate showed significant (P < 0.05) lipase inhibition above concentrations of 15 μg/mL in S. aureus and was not cytotoxic up to 25 μg/mL. For S. epidermidis, GML showed significant (P < 0.05) lipase inhibition above 7.5 μg/mL. Lipase activity varied between species and between strains. Staphylococcal spp. produced higher lipase activity compared with P. acnes and Corynebacterium spp. Glycerol monolaurate inhibited lipase production by S. aureus and S. epidermidis at concentrations that did not adversely affect bacterial cell growth. GML can be used to inhibit ocular bacterial lipase production without proving detrimental to commensal bacteria viability.

  2. The shelf life extension of refrigerated grass carp (Ctenopharyngodon idellus) fillets by chitosan coating combined with glycerol monolaurate.

    Science.gov (United States)

    Yu, Dawei; Jiang, Qixing; Xu, Yanshun; Xia, Wenshui

    2017-08-01

    A novel chitosan-based coating solution was prepared by combining glycerol monolaurate (GML) for shelf life extension of refrigerated grass carp fillets. The control and coated fillets were analyzed periodically for physicochemical (pH, thiobarbituric acid (TBA) value, total volatile basic nitrogen (TVB-N) value, K value, and shear force), microbiological (total viable counts (TVC), psychrophilic bacteria counts (PTC), Pseudomonads and H 2 S-producing bacteria) and sensorial characteristics. The results showed that chitosan-GML coated samples presented better quality preservation effects than chitosan coating alone. In addition, 2% chitosan enriched with 0.3% GML showed the significant (Pchitosan coating enriched with GML was a promising method to extend the shelf life of refrigerated fillets. Copyright © 2017. Published by Elsevier B.V.

  3. Evaluation of antimicrobial activity of glycerol monolaurate nanocapsules against American foulbrood disease agent and toxicity on bees.

    Science.gov (United States)

    Lopes, Leonardo Q S; Santos, Cayane G; de Almeida Vaucher, Rodrigo; Gende, Liesel; Raffin, Renata P; Santos, Roberto C V

    2016-08-01

    The American Foulbrood Disease (AFB) is a fatal larval bee infection. The etiologic agent is the bacterium Paenibacillus larvae. The treatment involves incineration of all contaminated materials, leading to high losses. The Glycerol Monolaurate (GML) is a known antimicrobial potential compound, however its use is reduced due to its low solubility in water and high melting point. The nanoencapsulation of some drugs offers several advantages like improved stability and solubility in water. The present study aimed to evaluate the antimicrobial activity against P. larvae and the toxicity in bees of GML nanoparticles. The nanocapsules were produced and presented mean diameter of 210 nm, polydispersity index of 0.044, and zeta potential of -23.4 mV demonstrating the acceptable values to predict a stable system. The microdilution assay showed that it is necessary 142 and 285 μg/mL of GML nanocapsules to obtain a bacteriostatic and bactericidal effect respectively. The time-kill curve showed the controlled release of compound, exterminating the microorganism after 24 h. The GML nanocapsules were able to kill the spore form of Paenibacillus larvae while the GML do not cause any effect. The assay in bees showed that the GML has a high toxicity while the GML nanoparticles showed a decrease on toxic effects. Concluding, the formulation shows positive results in the action to combat AFB besides not causing damage to bees. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Evaluation of Vaginal Drug Levels and Safety of a Locally Administered Glycerol Monolaurate Cream in Rhesus Macaques.

    Science.gov (United States)

    Kirtane, Ameya R; Rothenberger, Meghan K; Frieberg, Abby; Nephew, Karla; Schultz-Darken, Nancy; Schmidt, Thomas; Reimann, Thomas; Haase, Ashley T; Panyam, Jayanth

    2017-07-01

    The human immunodeficiency virus epidemic affects millions of people worldwide. As women are more vulnerable to infection, female-controlled interventions can help control the spread of the disease significantly. Glycerol monolaurate (GML), an inexpensive and safe compound, has been shown to protect against simian immunodeficiency virus infection when applied vaginally. However, on account of its low aqueous solubility, fabrication of high-dose formulations of GML has proven difficult. We describe the development of a vaginal cream that could be loaded with up to 35% GML. Vaginal drug levels and safety of 3 formulations containing increasing concentrations of GML (5%w/w, 15%w/w, and 35%w/w) were tested in rhesus macaques after vaginal administration. GML concentration in the vaginal tissue increased as the drug concentration in the cream increased, with 35% GML cream resulting in tissue concentration of ∼0.5 mg/g, albeit with high interindividual variability. Compared with the vehicle control, none of the GML creams had any significant effect on the vaginal flora and cytokine (macrophage inflammatory protein 3α and interleukin 8) levels, suggesting that high-dose GML formulations do not induce local adverse effects. In summary, we describe the development of a highly loaded vaginal cream of GML, and vaginal drug levels and safety after local administration in macaques. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  5. Glycerol monolaurate and dodecylglycerol effects on Staphylococcus aureus and toxic shock syndrome toxin-1 in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Ying-Chi Lin

    2009-10-01

    Full Text Available Glycerol monolaurate (GML, a 12 carbon fatty acid monoester, inhibits Staphylococcus aureus growth and exotoxin production, but is degraded by S. aureus lipase. Therefore, dodecylglycerol (DDG, a 12 carbon fatty acid monoether, was compared in vitro and in vivo to GML for its effects on S. aureus growth, exotoxin production, and stability.Antimicrobial effects of GML and DDG (0 to 500 microg/ml on 54 clinical isolates of S. aureus, including pulsed-field gel electrophoresis (PFGE types USA200, USA300, and USA400, were determined in vitro. A rabbit Wiffle ball infection model assessed GML and DDG (1 mg/ml instilled into the Wiffle ball every other day effects on S. aureus (MN8 growth (inoculum 3x10(8 CFU/ml, toxic shock syndrome toxin-1 (TSST-1 production, tumor necrosis factor-alpha (TNF-alpha concentrations and mortality over 7 days. DDG (50 and 100 microg/ml inhibited S. aureus growth in vitro more effectively than GML (p<0.01 and was stable to lipase degradation. Unlike GML, DDG inhibition of TSST-1 was dependent on S. aureus growth. GML-treated (4 of 5; 80% and DDG-treated rabbits (2 of 5; 40% survived after 7 days. Control rabbits (5 of 5; 100% succumbed by day 4. GML suppressed TNF-alpha at the infection site on day 7; however, DDG did not (<10 ng/ml versus 80 ng/ml, respectively.These data suggest that DDG was stable to S. aureus lipase and inhibited S. aureus growth at lower concentrations than GML in vitro. However, in vivo GML was more effective than DDG by reducing mortality, and suppressing TNF-alpha, S. aureus growth and exotoxin production, which may reduce toxic shock syndrome. GML is proposed as a more effective anti-staphylococcal topical anti-infective candidate than DDG, despite its potential degradation by S. aureus lipase.

  6. Detecting the quality of glycerol monolaurate: a method for using Fourier transform infrared spectroscopy with wavelet transform and modified uninformative variable elimination.

    Science.gov (United States)

    Chen, Xiaojing; Wu, Di; He, Yong; Liu, Shou

    2009-04-06

    Glycerol monolaurate (GML) products contain many impurities, such as lauric acid and glucerol. The GML content is an important quality indicator for GML production. A hybrid variable selection algorithm, which is a combination of wavelet transform (WT) technology and modified uninformative variable eliminate (MUVE) method, was proposed to extract useful information from Fourier transform infrared (FT-IR) transmission spectroscopy for the determination of GML content. FT-IR spectra data were compressed by WT first; the irrelevant variables in the compressed wavelet coefficients were eliminated by MUVE. In the MUVE process, simulated annealing (SA) algorithm was employed to search the optimal cutoff threshold. After the WT-MUVE process, variables for the calibration model were reduced from 7366 to 163. Finally, the retained variables were employed as inputs of partial least squares (PLS) model to build the calibration model. For the prediction set, the correlation coefficient (r) of 0.9910 and root mean square error of prediction (RMSEP) of 4.8617 were obtained. The prediction result was better than the PLS model with full-spectra data. It was indicated that proposed WT-MUVE method could not only make the prediction more accurate, but also make the calibration model more parsimonious. Furthermore, the reconstructed spectra represented the projection of the selected wavelet coefficients into the original domain, affording the chemical interpretation of the predicted results. It is concluded that the FT-IR transmission spectroscopy technique with the proposed method is promising for the fast detection of GML content.

  7. The Preventive Role of Pioglitazone in Glycerol-Induced Acute Kidney Injury in Rats during Two Different Treatment Periods

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    Rama Mousleh

    2018-03-01

    Full Text Available Background: Acute kidney injury is the most life-threatening complication of rhabdomyolysis. Glycerol is commonly used to induce this injury. The aim was to investigate the renoprotective effects of pioglitazone and the possible advantage of administering the drug for a longer period. Methods: Twenty-four male Albino Wistar rats were randomly divided into 4 groups (n=6/group: (A control, (B glycerol (50%, 10 mL/kg intramuscularly, (C glycerol+pioglitazone (10 mg/kg orally for 3 days, and (D glycerol+pioglitazone (for 6 days. Serum urea and creatinine levels were measured to assess the renal function. Reduced glutathione (GSH levels and histological alterations were also measured. Statistical analysis was performed using Prism (version 6. The numerical data were evaluated by ANOVA, followed by the Tukey tests. The categorical data were evaluated by the Mann–Whitney test and the Fisher exact tests. P<0.05 was considered significant. Results: In the glycerol-injected rats, the serum urea and creatinine levels were increased (P<0.001, while the GSH levels were decreased (P<0.001 compared to Group A. The nephrotoxicity showed significant tubular (P=0.01 and glomerular (P=0.02 injuries. In the pioglitazone-treated rats, the changes in the serum biomarkers and in the GSH levels were reversed in Group C (P=0.01 and in Group D (P=0.01. The microscopic examinations of the kidneys also showed some improvement. No obvious statistically significant difference was found between these 2 preventive groups in most studied features. Conclusion: These results indicate that pioglitazone might have nephroprotective effects in this injury model. Pioglitazone succeeded in producing this effect within 3 days. Doubling the drug administration period did not produce any significant superior benefit.

  8. Influence of Surfactant Sorbitan Monolaurate to Suspension Polymerization of Polyacrylic Acid Super absorbent

    International Nuclear Information System (INIS)

    Dewi Sondari; Nuri Astrini; Lik Anah; Agus Haryono

    2008-01-01

    A super absorbent polymer has been prepared by suspension polymerization reaction using acrylic acid, sodium hydroxide, cyclohexane, potassium persulfate as initiator and sorbitan monolaurate as surfactant. The effect of different weight ratio of acrylic acid/sorbitan monolaurate 20/1, 20/2 and 20/3 were investigated based on its swelling properties, chemical structure by using Fourier Transform-Infra Red (FTIR) Spectroscopy and the surface morphology by scanning electron microscopy (SEM). The molecular weight of polyacrylic acid super absorbent was determinate by intrinsic viscosity measurements in 2 M aqueous sodium hydroxide at 25 o C. The study showed sample with weight ratio of acrylic acid/sorbitan monolaurate = 20/2 have best swelling properties. (author)

  9. 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.

  10. Structural investigation of diglycerol monolaurate reverse micelles in nonpolar oils cyclohexane and octane

    International Nuclear Information System (INIS)

    Shrestha, Lok Kumar; Aramaki, Kenji

    2009-01-01

    Structure of diglycerol monolaurate (abbreviated as C 12 G 2 ) micelles in nonpolar oils cyclohexane and n-octane as a function of compositions, temperatures, and surfactant chain length has been investigated by small-angle X-ray scattering (SAXS). The SAXS data were evaluated by the generalized indirect Fourier transformation (GIFT) method and real-space structural information of particles was achieved. Conventional poly(oxyethylene) type nonionic surfactants do not form reverse micelles in oils unless a trace water is added. However, present surfactant C 12 G 2 formed reverse micelle (RM) in cyclohexane and n-octane without addition of water at normal room temperature. A clear signature of one dimensional (1-D) micellar growth was found with increasing C 12 G 2 concentration. On the other hand, increasing temperature or hydrocarbon chain length of surfactant shorten the length of RM, which is essentially a cylinder-to-sphere type transition in the aggregate structure. Drastic changes in the structure of RM, namely, transition of ellipsoidal prolate to long rod-like micelles was observed upon changing oil from cyclohexane to octane. All the microstructural transitions were explained in terms of critical packing parameter. (author)

  11. 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.

  12. Glycerol tertiary butyl ethers via etherification of glycerol with isobutene

    Energy Technology Data Exchange (ETDEWEB)

    Behr, A. [Dortmund Univ. (Germany). Chair of Chemical Process Development/Technical Chemistry A

    2007-07-01

    Glycerol and isobutene can react to a mixture of glycerol tertiary butyl ethers (GTBE) which can be used as additives for gasoline, diesel or biodiesel. This reaction was investigated in lab scale yielding a proposal for a process flow diagram containing reaction, extraction, flash and rectification units. This process has the advantages that only the suitable higher ethers are formed and that both glycerol and isobutene are fully converted. The homogeneous acid catalyst is low-priced and can be completely recycled. (orig.)

  13. Calibrating the glycerol dialkyl glycerol tetraether temperature signalin speleothems

    NARCIS (Netherlands)

    Blyth, A.J.; Schouten, S.

    2013-01-01

    Palaeotemperature proxies based on glycerol dialkyl glycerol tetraethers (GDGTs) lipids have been established for marine and lacustrine environments, but there has been relatively little study of their application in speleothems. In this study we analyse the GDGT content of 33 speleothem samples

  14. Calibrating the glycerol dialkyl glycerol tetraether temperature signal in speleothems

    NARCIS (Netherlands)

    Blyth, A.J.; Schouten, S.|info:eu-repo/dai/nl/137124929

    2013-01-01

    Palaeotemperature proxies based on glycerol dialkyl glycerol tetraethers (GDGTs) lipids have been established for marine and lacustrine environments, but there has been relatively little study of their application in speleothems. In this study we analyse the GDGT content of 33 speleothem samples

  15. Prevention of Flares in Children with Atopic Dermatitis with Regular Use of an Emollient Containing Glycerol and Paraffin: A Randomized Controlled Study.

    Science.gov (United States)

    Tiplica, George Sorin; Kaszuba, Andrzej; Malinauskienė, Laura; Konno, Pille; Boralevi, Franck; Garrigue, Eric; Saint-Aroman, Markéta; Delarue, Alain

    2017-05-01

    Emollients are part of the standard treatment for atopic dermatitis (AD), although there is limited evidence that regular use of emollients as management therapy reduces the frequency of flares and corticosteroid consumption. The objective of this study was to evaluate the benefit of emollient use in the management of mild to moderate AD in children by assessing the ability of two different emollients (particularly V0034CR) to prevent flares and to reduce the use of corticosteroids. In this randomized, open-label study, patients with a current flare were treated with a potent topical corticosteroid. After flare resolution, patients were centrally randomized to V0034CR emollient, reference emollient, or no emollient (1:1:1 ratio) for 12 weeks. New flares were medically assessed before being treated with a moderately potent corticosteroid. A total of 335 children 2 to 6 years of age were randomized. At 12 weeks, the percentage of patients with one or more flares was statistically significantly lower with V0034CR (35.1%) than without emollient (67.6%; p < 0.001). Fewer patients treated with V0034CR required any corticosteroids or immunosuppressants (23.6%) than patients with no emollient (43.3%) at 12 weeks. The difference was significant at all time points (p = 0.002). Patients treated with emollients had a longer time to first flare, fewer flares, higher complete remission rates, less corticosteroid consumption, lower Investigator Global Assessment scores, and lower Scoring Atopic Dermatitis scores than those who were not. V0034CR was well tolerated, with no specific safety concerns. Regular emollient use in children with mild to moderate AD reduces flares and corticosteroid consumption. © 2017 Wiley Periodicals, Inc.

  16. Quantitative analysis of glycerol accumulation, glycolysis and growth under hyper osmotic stress.

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    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

  17. Biohydrogen Production from Glycerol using Thermotoga spp

    NARCIS (Netherlands)

    Maru, B.T.; Bielen, A.A.M.; Kengen, S.W.M.; Constantini, M.; Medina, F.

    2012-01-01

    Given the highly reduced state of carbon in glycerol and its availability as a substantial byproduct of biodiesel production, glycerol is of special interest for sustainable biofuel production. Glycerol was used as a substrate for biohydrogen production using the hyperthermophilic bacterium,

  18. Glycerol metabolism of Lactobacillus rhamnosus ATCC 7469: cloning and expression of two glycerol kinase genes.

    Science.gov (United States)

    Alvarez, María de Fátima; Medina, Roxana; Pasteris, Sergio E; Strasser de Saad, Ana M; Sesma, Fernando

    2004-01-01

    Lactobacillus rhamnosus ATCC 7469 was able to grow in glycerol as the sole source of energy in aerobic conditions, producing lactate, acetate, and diacetyl. A biphasic growth was observed in the presence of glucose. In this condition, glycerol consumption began after glucose was exhausted from the culture medium. Glycerol kinase activity was detected in L. rhamnosus ATCC 7469, a characteristic of microorganisms which catabolize glycerol in aerobic conditions. Genetic analysis revealed that this strain possesses two glycerol kinase genes: gykA and glpK, that encode for two different glycerol kinases GykA and GlpK, respectively. The glpK geneis associated in an operon with alpha-glycerophosphate oxidase (glpO) and glycerol facilitator (glpF) genes. Transcriptional analysis revealed that only glpK is expressed when L. rhamnosus was grown on glycerol. Copyright 2004 S. Karger AG, Basel

  19. 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

  20. Enhanced transdermal delivery with less irritation by magainin pore-forming peptide with a N-lauroylsarcosine and sorbitan monolaurate mixture.

    Science.gov (United States)

    Lee, Haerin; Park, Juhyun; Kim, Yeu-Chun

    2018-02-01

    Transdermal drug delivery is advantageous over other conventional drug administration routes. However, it can be inefficient because of the natural barrier of the stratum corneum which is the uppermost layer of the skin. A previous study verified that the treatment of magainin pore-forming peptide with N-lauroylsarcosine (NLS) on human skin can increase skin permeability by 47-fold. However, NLS is well known as a potential skin irritant. The irritation potential of NLS is known to decrease when mixed with sorbitan monolaurate (S20). Encouraged by these results, we combined S20 with magainin-NLS to enhance transdermal drug transport with less skin irritation. In this study, nine groups with magainin and NLS:S20 mixtures at different concentrations and weight fractions were screened to maximize their synergistic effect. To quantify the efficacy to toxicity ratio of each formulation, we defined the ratio as the "enhancement ratio/irritation potential (ER/IP)." The ER was observed by Franz cell diffusion of the target drug fluorescein, and the IP was measured by the cytotoxicity of the NIH/3T3 mouse fibroblast cell line. As a result, the magainin with the NLS:S20 mixture increased the permeability of porcine skin as well as decreased the toxicity. Among the various combinations, a formulation of 2% (w/v) NLS:S20 with a weight fraction of 0.6:0.4 had the largest ER/IP. ATR-FTIR spectroscopy of the formulations and skin was done to analyze the interactions in the formulations themselves and between the formulations and the skin. Both the intercellular lipidic route and transcellular route through the stratum corneum protein were involved in the delivery of fluorescein. This study turned pore-forming peptides into an efficient and safe penetration enhancer by combining them with other chemical penetration enhancers. Moreover, this discovery could be a possible method for enabling the transdermal delivery of macromolecules.

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

    Directory of Open Access Journals (Sweden)

    Mathias Klein

    2016-12-01

    Full Text Available 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 gDW/gglycerol 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. Keywords: Yeast, Saccharomyces cerevisiae, Glycerol, Transport, Glycerol facilitator, Fps1, Stl1

  2. The Lubricity of Glycerol and its Solutions

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Jakobsen, J.

    2016-01-01

    Glycerol has been recognised as an excellent diesel fuel and lubricant. It is a liquid that can originate from the transesterification of plant oil that also results in plant oil metyl (or ethyl) ester (biodiesel). Machine elements lubricated by glycerol show very low friction, in fact lower than...

  3. Synthesis and applications of 13C glycerol

    International Nuclear Information System (INIS)

    Stocking, E.; Khalsa, O.; Martinez, R.A.; Silks, L.A. III

    1994-01-01

    Due in part to the use of labeled glycerol for the 13 C enrichment of biomolecules, we are currently developing new synthetic routes to various isotopomers of glycerol. Judging from our experience, traditional methods of glycerol synthesis are not easily adapted for isotopic enrichment and/or have poor overall yields (12 to 15%). Furthermore, the use of glycerol for enrichment can be prohibitively expensive and its availability is limited by the level of demand. We are presently developing a short de novo synthesis of glycerol from carbon dioxide (∼53% overall yield for four steps) and are examining the feasibility of synthesizing site-specific 13 C-labeled glycerol and dihydroxyacetone (DHA) from labeled methanol and carbon dioxide. One application of 13 C glycerol we have examined is enzymatic conversion of glycerol to glyceraldehyde-3-monophosphate or dihydroxyacetone monophosphate (DHAP) with yields ranging from 25 to 50% (as determined by NMR spectroscopy). We are also pursuing the chemical conversion of 13 C-labeled DHA to DHAP. We are especially interested in 13 C-labeled DHAP because we are investigating its use as a chemo-enzymatic precursor for both labeled 2-deoxyribose and 2-deoxyribonucleic acids

  4. Distribution of glycerol dialkyl glycerol tetraethers in Tibetan hot springs

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    Liu He

    2012-05-01

    Full Text Available Isoprenoidal glycerol dialkyl glycerol tetraethers (iGDGTs from the Gulu hot springs (23–83.6 °C, pH > 7 and Yangbajing hot springs (80–128 °C, pH > 7 were analyzed in order to investigate the distribution of archaeal lipids among different hot springs in Tibet. A soil sample from Gulu was incubated at different temperatures and analyzed for changes in iGDGTs to help evaluate whether surrounding soil may contribute to the iGDGTs in hot springs. The sources of bacterial GDGTs (bGDGTs in these hot springs were also investigated. The results revealed different profiles of iGDGTs between Gulu and Yangbajing hot springs. Core iGDGTs and polar iGDGTs also presented different patterns in each hot spring. The PCA analysis showed that the structure of polar iGDGTs can be explained by three factors and suggested multiple sources of these compounds. Bivariate correlation analysis showed significant positive correlations between polar and core bGDGTs, suggesting the in situ production of bGDGTs in the hot springs. Furthermore, in the soil incubation experiment, temperature had the most significant influence on concentration of bGDGTs rather than iGDGTs, and polar bGDGTs had greater variability than core bGDGTs with changing temperature. Our results indicated that soil input had little influence on the composition of GDGTs in Tibetan hot springs. On the other hand, ring index and TEX86 values were both positively correlated with incubation temperature, suggesting that the structure of archaeal lipids changed in response to varying temperature during incubation.

  5. 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.

  6. Synthesis and applications of 13C glycerol

    International Nuclear Information System (INIS)

    Stocking, E.; Khalsa, O.; Martinez, R.; Silks, L.A. III

    1994-01-01

    The authors are currently developing new synthetic routes to the various isotopomers of glycerol. Labeled glycerol is useful for 13 C enrichment of biomolecules. However, traditional methods of glycerol synthesis are not easily adapted for isotopic enrichment or have poor overall yields (12-15%). In addition, the use of glycerol for enrichment can be prohibitively expensive and its availability depends on the level of demand. The authors have developed a short de novo synthesis of [U- 13 C]glycerol from carbon dioxide (∼53% overall yield for four steps) and are currently examining the feasibility of synthesizing site-specific 13 C labeled glycerol and dihydroxyacetone (DHA) from methanol and carbon dioxide. The authors have examined the enzymatic conversion of [U- 13 C]glycerol to glyceraldehyde-3-monophosphate or dihydroxyacetone monophosphate (DHAP) with yields ranging from 25-50% (as determined by NMR spectroscopy). The authors are also pursuing the chemical conversion of 13 C labeled DHA to DHAP and the results are presented. Labeled DHAP is a possible enzymatic precursor for both labeled 2-deoxyribose and 2-deoxyribonucleic acids

  7. Glycerol production by fermenting yeast cells is essential for optimal bread dough fermentation.

    Directory of Open Access Journals (Sweden)

    Elham Aslankoohi

    Full Text Available Glycerol is the main compatible solute in yeast Saccharomyces cerevisiae. When faced with osmotic stress, for example during semi-solid state bread dough fermentation, yeast cells produce and accumulate glycerol in order to prevent dehydration by balancing the intracellular osmolarity with that of the environment. However, increased glycerol production also results in decreased CO2 production, which may reduce dough leavening. We investigated the effect of yeast glycerol production level on bread dough fermentation capacity of a commercial bakery strain and a laboratory strain. We find that Δgpd1 mutants that show decreased glycerol production show impaired dough fermentation. In contrast, overexpression of GPD1 in the laboratory strain results in increased fermentation rates in high-sugar dough and improved gas retention in the fermenting bread dough. Together, our results reveal the crucial role of glycerol production level by fermenting yeast cells in dough fermentation efficiency as well as gas retention in dough, thereby opening up new routes for the selection of improved commercial bakery yeasts.

  8. Glycerol production by fermenting yeast cells is essential for optimal bread dough fermentation.

    Science.gov (United States)

    Aslankoohi, Elham; Rezaei, Mohammad Naser; Vervoort, Yannick; Courtin, Christophe M; Verstrepen, Kevin J

    2015-01-01

    Glycerol is the main compatible solute in yeast Saccharomyces cerevisiae. When faced with osmotic stress, for example during semi-solid state bread dough fermentation, yeast cells produce and accumulate glycerol in order to prevent dehydration by balancing the intracellular osmolarity with that of the environment. However, increased glycerol production also results in decreased CO2 production, which may reduce dough leavening. We investigated the effect of yeast glycerol production level on bread dough fermentation capacity of a commercial bakery strain and a laboratory strain. We find that Δgpd1 mutants that show decreased glycerol production show impaired dough fermentation. In contrast, overexpression of GPD1 in the laboratory strain results in increased fermentation rates in high-sugar dough and improved gas retention in the fermenting bread dough. Together, our results reveal the crucial role of glycerol production level by fermenting yeast cells in dough fermentation efficiency as well as gas retention in dough, thereby opening up new routes for the selection of improved commercial bakery yeasts.

  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. Electrochemical Oxidation of Glycerol Using Gold Electrode

    International Nuclear Information System (INIS)

    Mohamed Rozali Othman; Amirah Ahmad

    2015-01-01

    Cyclic voltammetry, potential linear V and chronocuolometry methods were carried out to gain electrochemical behavior of glycerol at a gold electrode. Potassium hydroxide and sulfuric acid were chosen to be the electrolyte for the electro-oxidation of this organic compound. Besides gold plate electrode, gold composite electrode (Au-PVC) was also used as the working electrode. The Au-PVC composite electrode was characterized by Scanning Electron Microscopy (SEM) to determine its morphological aspects before and after used in electrochemical oxidation of glycerol. In alkaline solution, the adsorption of hydroxide species onto the surface of both gold plate and composite Au-PVC electrodes occurs at potential around 500 mV vs SCE. However, at gold plate electrode, there was a small, broad peak before the drastic escalation of current densities which indicates the charge transfer of the chemisorbed OH - anion. In acidic media, the gold oxide was formed after potential 1.0 V. From the cyclic voltammogram glycerol undergo oxidation twice in potassium hydroxide at gold plate and Au-PVC composite electrodes, while in sulfuric acid, oxidation reaction happened once for glycerol on the gold plate electrode. Overall, electrochemical oxidation of glycerol was more effective in alkaline media. Tafel graph which plotted from potential linear V method shows that Au-PVC composite electrode is better than gold plate electrode for the electro-oxidation of glycerol in alkaline solution. Electrochemical oxidation of glycerol products as analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) produced several carboxylic acids and phenolic compounds. (author)

  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. 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%

  13. Catalytic glycerol steam reforming for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Dan, Monica, E-mail: monica.dan@itim-cj.ro; Mihet, Maria, E-mail: maria.mihet@itim-cj.ro; Lazar, Mihaela D., E-mail: diana.lazar@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat Street, 400293 Cluj Napoca (Romania)

    2015-12-23

    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{sub 2}. In this work we present the results obtained in the process of steam reforming of glycerol on Ni/Al{sub 2}O{sub 3}. The catalyst was prepared by wet impregnation method and characterized through different methods: N{sub 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{sub 2}, CH{sub 4}, CO, CO{sub 2}. The optimum reaction conditions as resulted from this study are: temperature 550°C, Gly:H{sub 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%.

  14. 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.

  15. Design and analysis of fuel ethanol production from raw glycerol

    International Nuclear Information System (INIS)

    Posada, J.A.; Cardona, C.A.

    2010-01-01

    Three configurations for fuel ethanol production from raw glycerol using Escherichia coli were simulated and economically assessed using Aspen Plus and Aspen Icarus, respectively. These assessments considered raw glycerol (60 wt%) purification to both crude glycerol (88 wt%) and pure glycerol (98 wt%). The highest purification cost (PC) was obtained using pure glycerol due to its higher energy consumption in the distillation stage. In addition, the remaining methanol in the raw glycerol stream was recovered and recycled, decreasing the purification costs. The E. coli strain is able to convert crude glycerol (at 10 g/L or 20 g/L), or pure glycerol (at 10 g/L) to ethanol. Among these three glycerol concentrations, the lowest bioconversion cost was obtained when crude glycerol was diluted at 20 g/L. Purification and global production costs were compared with the commercial prices of glycerol and fuel ethanol from corn and sugarcane. Purification costs of raw glycerol were lower than previously reported values due to the methanol recovery. Global production costs for fuel ethanol from glycerol were lower than the reported values for corn-based production and higher than those for cane-based production. (author)

  16. 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 c...... hyperglycemia, GIP increases femoral artery blood flow with no effect on glucose metabolism, whereas GLP-1 increases glucose disposal, potentially, however, due to increased insulin levels....... 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 (Plevels, no differences between trials were seen for GIR or glucose Rd. Besides...

  17. 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…

  18. 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

  19. 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.

  20. 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

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

    DEFF Research Database (Denmark)

    Holm, Anders Koefoed

    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...... already present in L. lactis. The construction and verification of a strain with increased glycerol kinase activity was not fully completed and is still ongoing. Similarly the construction of mutants expressing a heterologous pathway for glycerol dissimilation is also an ongoing task. An artificial...... effects and improve the growth rate, though not completely to the level of the reference strain. The fact that this effect was predominantly observed while utilizing xylose implicates the involvement of the pentose phosphate pathway. A possible mechanism underlying the observed growth characteristics...

  2. 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

  3. 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)

  4. Rapid monitoring of glycerol in fermentation growth media: Facilitating crude glycerol bioprocess development.

    Science.gov (United States)

    Abad, Sergi; Pérez, Xavier; Planas, Antoni; Turon, Xavier

    2014-04-01

    Recently, the need for crude glycerol valorisation from the biodiesel industry has generated many studies for practical and economic applications. Amongst them, fermentations based on glycerol media for the production of high value metabolites are prominent applications. This has generated a need to develop analytical techniques which allow fast and simple glycerol monitoring during fermentation. The methodology should be fast and inexpensive to be adopted in research, as well as in industrial applications. In this study three different methods were analysed and compared: two common methodologies based on liquid chromatography and enzymatic kits, and the new method based on a DotBlot assay coupled with image analysis. The new methodology is faster and cheaper than the other conventional methods, with comparable performance. Good linearity, precision and accuracy were achieved in the lower range (10 or 15 g/L to depletion), the most common range of glycerol concentrations to monitor fermentations in terms of growth kinetics. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Anti-irritant and anti-inflammatory effects of glycerol and xylitol in sodium lauryl sulphate-induced acute irritation.

    Science.gov (United States)

    Szél, E; Polyánka, H; Szabó, K; Hartmann, P; Degovics, D; Balázs, B; Németh, I B; Korponyai, C; Csányi, E; Kaszaki, J; Dikstein, S; Nagy, K; Kemény, L; Erős, G

    2015-12-01

    Glycerol is known to possess anti-irritant and hydrating properties and previous studies suggested that xylitol may also have similar effects. Our aim was to study whether different concentrations of these polyols restore skin barrier function and soothe inflammation in sodium lauryl sulphate (SLS)-induced acute irritation. The experiments were performed on male SKH-1 hairless mice. The skin of the dorsal region was exposed to SLS (5%) for 3 h alone or together with 5% or 10% of glycerol respectively. Further two groups received xylitol solutions (8.26% and 16.52% respectively) using the same osmolarities, which were equivalent to those of the glycerol treatments. The control group was treated with purified water. Transepidermal water loss (TEWL) and skin hydration were determined. Microcirculatory parameters of inflammation were observed by means of intravital videomicroscopy (IVM). Furthermore, accumulation of neutrophil granulocytes and lymphocytes, the expression of inflammatory cytokines and SLS penetration were assessed, as well. Treatment with the 10% of glycerol and both concentrations of xylitol inhibited the SLS-induced elevation of TEWL and moderated the irritant-induced increase in dermal blood flow and in the number of leucocyte-endothelial interactions. All concentrations of the applied polyols improved hydration and prevented the accumulation of lymphocytes near the treatment site. At the mRNA level, neither glycerol nor xylitol influenced the expression of interleukin-1 alpha. However, expression of interleukin-1 beta was significantly decreased by the 10% glycerol treatment, while expression of tumour necrosis factor-alpha decreased upon the same treatment, as well as in response to xylitol. Higher polyol treatments decreased the SLS penetration to the deeper layers of the stratum corneum. Both of the analysed polyols exert considerable anti-irritant and anti-inflammatory properties, but the effective concentration of xylitol is lower than that of

  6. 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

  7. 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...

  8. Synthesis and applications of {sup 13}C glycerol

    Energy Technology Data Exchange (ETDEWEB)

    Stocking, E.; Khalsa, O.; Martinez, R.A.; Silks, L.A. III [Los Alamos National Laboratory, NM (United States)

    1994-12-01

    Due in part to the use of labeled glycerol for the {sup 13}C enrichment of biomolecules, we are currently developing new synthetic routes to various isotopomers of glycerol. Judging from our experience, traditional methods of glycerol synthesis are not easily adapted for isotopic enrichment and/or have poor overall yields (12 to 15%). Furthermore, the use of glycerol for enrichment can be prohibitively expensive and its availability is limited by the level of demand. We are presently developing a short de novo synthesis of glycerol from carbon dioxide ({approximately}53% overall yield for four steps) and are examining the feasibility of synthesizing site-specific {sup 13}C-labeled glycerol and dihydroxyacetone (DHA) from labeled methanol and carbon dioxide. One application of {sup 13}C glycerol we have examined is enzymatic conversion of glycerol to glyceraldehyde-3-monophosphate or dihydroxyacetone monophosphate (DHAP) with yields ranging from 25 to 50% (as determined by NMR spectroscopy). We are also pursuing the chemical conversion of {sup 13}C-labeled DHA to DHAP. We are especially interested in {sup 13}C-labeled DHAP because we are investigating its use as a chemo-enzymatic precursor for both labeled 2-deoxyribose and 2-deoxyribonucleic acids.

  9. 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...... 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...... 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...

  10. 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

  11. Industrial-scale application of Lactobacillus reuteri coupled with glycerol as a biopreservation system for inhibiting Clostridium tyrobutyricum in semi-hard ewe milk cheese.

    Science.gov (United States)

    Ávila, Marta; Gómez-Torres, Natalia; Delgado, David; Gaya, Pilar; Garde, Sonia

    2017-09-01

    The suitability of the biopreservation system formed by reuterin-producing L. reuteri INIA P572 and glycerol (required for reuterin production) to prevent late blowing defect (LBD) was evaluated in industrial sized semi-hard ewe milk cheese contaminated with Clostridium tyrobutyricum INIA 68, a wild strain isolated from a LBD cheese. For this purpose, six batches of cheese were made (three with and three without clostridial spores): control cheeses with lactococci starter, cheeses with L. reuteri as adjunct, and cheeses with L. reuteri and 30 mM glycerol. Spores of C. tyrobutyricum INIA 68 germinated during pressing of cheese curd, causing butyric acid fermentation in cheese after 30 d of ripening. The addition of L. reuteri, without glycerol, enhanced the symptoms and the formation of volatile compounds associated with LBD. When glycerol was added to cheese milk contaminated with C. tyrobutyricum, L. reuteri was able to produce reuterin in cheese resulting in cheeses with a uniform cheese matrix and a volatile profile similar to cheese made with L. reuteri and glycerol (without spores). Accordingly, L. reuteri INIA P572 coupled with glycerol seems a novel biopreservation system to inhibit Clostridium growth and prevent LBD by means of in situ reuterin production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. 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"2"1–5.66 × 10"2"1/m"3, 0.92–1.07 nm and 1.00 × 10"−"1"1–1.79 × 10"−"1"1 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.

  13. 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.

  14. Glycerol acetals, kinetic study of the reaction between glycerol and formaldehyde

    International Nuclear Information System (INIS)

    Agirre, I.; Garcia, I.; Requies, J.; Barrio, V.L.; Gueemez, M.B.; Cambra, J.F.; Arias, P.L.

    2011-01-01

    The acetalization reaction between glycerol and formaldehyde using Amberlyst 47 acidic ion exchange resin was studied. These acetals can be obtained from renewable sources (bioalcohols and bioalcohol derived aldehydes) and seem to be good candidates for different applications such as oxygenated diesel additives. A preliminary kinetic study was performed in a batch stirred tank reactor studying the influence of different process parameters like temperature, feed composition and the stirring speed. A pseudo homogenous kinetic model able to explain the reaction mechanism was adjusted. Thus, the corresponding order of reaction was determined. Amberlyst 47 acidic ion exchange resin showed a fairly good behavior allowing 100% of selectivity towards acetals formation. However, the studied acetalization reaction showed high thermodynamic limitations achieving glycerol conversions around 50% using a stoichiometric feed ratio at 353 K. The product is a mixture of two isomers (1,3-Dioxan-5-ol and 1,3-dioxolane-4-methanol) and the conversion of 1,3-dioxolane-4-methanol into 1,3-Dioxan-5-ol was also observed. -- Highlights: → The reaction between glycerol and acetaldehyde shows thermodynamic limitations. → Amberlyst 47 ion exchange resins show 100% of selectivity. → A pseudo-homogeneous kinetic model is able to predict the reaction progress. → Isomerization reactions were observed from dioxalanes to dioxanes.

  15. Halophilic biohydrogen and 1,3-propanediol production from raw glycerol: A genomic perspective

    Energy Technology Data Exchange (ETDEWEB)

    Kivisto, A.

    2013-11-01

    Glycerol is produced in large amounts as a by-product in biodiesel industry (10 kg per 100 kg biodiesel). By-products and waste materials are typically economical substrates for bioprocesses. Furthermore, microorganisms are able to combine the degradation of organic material with production of a wide range of metabolites and other cellular products. The current biotechnological interest of industrial glycerol lies on bioprocesses yielding environmentally friendly energy carrier molecules (hydrogen, methane, ethanol, butanol) and reduced chemicals (1,3-propanediol, dihydroxyacetone). Industrial glycerol also called as raw or crude glycerol, however, is a challenging substrate for microorganisms due to its impurities including alcohol, soaps, salts and metals. Halophiles (the salt-loving microorganisms) require salt for growth and heavy metal resistances have been characterized for numerous halophiles. Therefore, halophiles are potentially useful for the utilization of raw glycerol from biodiesel waste streams without pre-processing. Another challenge for large-scale microbial bioprocesses is a potential contamination with unfavorable microorganisms. For example, H{sub 2}-producing systems tend to get contaminated with H{sub 2}-consuming microorganisms. Extremophiles are organisms that have been adapted for life under extreme conditions, such as high salinity, high or low temperature, asidic or basic pH, dryness or high pressure. For extremophilic pure cultures contamination and thus the need to ensure a sterile environment might not be a problem due to the extreme process conditions that efficiently prevent the growth of most other bacteria. In addition, hypersaline environments (above 12 % NaCl) do not support the growth of H{sub 2} utilizing methanogens due to bioenergetic reasons. Halophilic fermentative H{sub 2} producers, on the other hand, have been shown to be active up to near salt saturation. The aims of the present study can be divided into two categories

  16. Prevention

    DEFF Research Database (Denmark)

    Halken, S; Høst, A

    2001-01-01

    , breastfeeding should be encouraged for 4-6 months. In high-risk infants a documented extensively hydrolysed formula is recommended if exclusive breastfeeding is not possible for the first 4 months of life. There is no evidence for preventive dietary intervention neither during pregnancy nor lactation...... populations. These theories remain to be documented in proper, controlled and prospective studies. Breastfeeding and the late introduction of solid foods (>4 months) is associated with a reduced risk of food allergy, atopic dermatitis, and recurrent wheezing and asthma in early childhood. In all infants....... Preventive dietary restrictions after the age of 4-6 months are not scientifically documented....

  17. [Effects of glycerol on the spectral properties of sodium caseinate].

    Science.gov (United States)

    Li, Yan; Chang, Fen-fen; Gao, Huan-yuan; Cao, Qing; Jin, Li-e

    2015-01-01

    Although the immigration of water molecule, and diffusion and traversing of oxygen can be prevented by the edible film prepared through sodium caseinate, which plays a good protection role for the food, the strong hydrophilicity makes its watertightness and mechanical properties become inferior. Because the toughness and water resistance of SC films can be enhanced by glycerol (G) as an additive, it is necessary to elucidate the interaction between G and SC through the spectral characteristics such as fluorescence spectra, infrared spectra and UV spectra. The results show that the fluorescence intensity of SC decreases due to the addition of G. The binding constant obtained by the double logarithmic regression curve analysis is 1. 127 x 10(3) L . mol-1 and the number of binding sites reaches 1. 161. It indicates that the weak chemical bond is primary between G and SC molecules; From IR the absorption peaks of SC are almost the same before and after adding G. However, there is a certain difference among their absorption intensities. It reveals that the secondary structure of SC is affected, β folding length decreases, α helix, random coil structure, β angle structure increases, and the intermolecular hydrogen bond is strengthened; From UV the peptide bond structure of SC is not changed after the addition of G, but the polymer with larger molecular weight, which is formed by non-covalent bond, makes the peak intensity decrease. The research gives the mode of G and SC from the molecular level.

  18. 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.

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

    African Journals Online (AJOL)

    Tuoyo Aghomotsegin

    2016-10-12

    Oct 12, 2016 ... glycerol waste by mutant Enterobacter aerogenes ... wild type strain was altered for enhancing ethanol production using UV irradiation and chemical method. .... microbial medium analytical methods were of laboratory and.

  20. 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.

  1. Enhancement of glycerol production by zygosaccharomyces ruxii using strawberry wastes

    International Nuclear Information System (INIS)

    Meleigy, S.A; Taha, S.M.A.

    2010-01-01

    Glycerol is important industrial product that can be produced using osmophilic yeasts. In this study a local isolate of osmophilic yeast, zygosaccharomyces ruxii, was used for glycerol production from strawberry waste. The effects of some important parameters including glucose and urea concentrations, incubation temperature, initial ph and gamma irradiation were investigated. The optimum conditions for maximum glycerol production (126.8 g/l)by z. ruxii were occurred at 31 degree C and initial ph 5 in the presence of 250 g/l glucose and 3 g/l urea in the production medium . Under these optimizing fermentation parameters, enhancement of glycerol production (130 g/l) were recorded when the inoculum of z. ruxii was exposed to 0.25 kGy. also, the present results showed reduction in BOD 5 levels of fermented strawberry waste.

  2. Crude glycerol combustion: Particulate, acrolein, and other volatile organic emissions

    KAUST Repository

    Steinmetz, Scott; Herrington, Jason S.; Winterrowd, Chris K.; Roberts, William L.; Wendt, Jost O L; Linak, William P.

    2013-01-01

    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

  3. 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

  4. 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...

  5. Synthesis and characterization of poly(glycerol citrate/sebacate)

    International Nuclear Information System (INIS)

    Brioude, Michel M.; Guimaraes, Danilo H.; Fiuza, Raigenis P.; Boaventura, Jaime S.; Jose, Nadia M.

    2011-01-01

    In this work were prepared and characterized the poly(glycerol citrate/sebacate) in three different ratios between acids. The polymers were prepared by a polycondensation reaction between glycerol and citric/sebacic acids and characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning differential calorimetry (DSC), scanning electron microscopy (SEM). The results showed that the polymers are polyesters and its crystallinity, thermal and morphological properties were modified by sebacic acid adding. (author)

  6. Efficient synthetic protocols in glycerol under heterogeneous catalysis.

    Science.gov (United States)

    Cravotto, Giancarlo; Orio, Laura; Gaudino, Emanuela Calcio; Martina, Katia; Tavor, Dorith; Wolfson, Adi

    2011-08-22

    The massive increase in glycerol production from the transesterification of vegetable oils has stimulated a large effort to find novel uses for this compound. Hence, the use of glycerol as a solvent for organic synthesis has drawn particular interest. Drawbacks of this green and renewable solvent are a low solubility of highly hydrophobic molecules and a high viscosity, which often requires the use of a fluidifying co-solvent. These limitations can be easily overcome by performing reactions under high-intensity ultrasound and microwaves in a stand-alone or combined manner. These non-conventional techniques facilitate and widen the use of glycerol as a solvent in organic synthesis. Glycerol allows excellent acoustic cavitation even at high temperatures (70-100 °C), which is otherwise negligible in water. Herein, we describe three different types of applications: 1) the catalytic transfer hydrogenation of benzaldehyde to benzyl alcohol in which glycerol plays the dual role of the solvent and hydrogen donor; 2) the palladium-catalyzed Suzuki cross-coupling; and (3) the Barbier reaction. In all cases glycerol proved to be a greener, less expensive, and safer alternative to the classic volatile organic solvents. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. 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.

  8. Utilization of Crude Glycerol as a Substrate for the Production of Rhamnolipid by Pseudomonas aeruginosa

    OpenAIRE

    Eraqi, Walaa A.; Yassin, Aymen S.; Ali, Amal E.; Amin, Magdy A.

    2016-01-01

    Biosurfactants are produced by bacteria or yeast utilizing different substrates as sugars, glycerol, or oils. They have important applications in the detergent, oil, and pharmaceutical industries. Glycerol is the product of biodiesel industry and the existing glycerol market cannot accommodate the excess amounts generated; consequently, new markets for refined glycerol need to be developed. The aim of present work is to optimize the production of microbial rhamnolipid using waste glycerol. We...

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

    OpenAIRE

    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...

  10. 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.

  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. 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)

  14. Assessing an effective feeding strategy to optimize crude glycerol utilization as sustainable carbon source for lipid accumulation in oleaginous yeasts.

    Science.gov (United States)

    Signori, Lorenzo; Ami, Diletta; Posteri, Riccardo; Giuzzi, Andrea; Mereghetti, Paolo; Porro, Danilo; Branduardi, Paola

    2016-05-05

    Microbial lipids can represent a valuable alternative feedstock for biodiesel production in the context of a viable bio-based economy. This production can be driven by cultivating some oleaginous microorganisms on crude-glycerol, a 10% (w/w) by-product produced during the transesterification process from oils into biodiesel. Despite attractive, the perspective is still economically unsustainable, mainly because impurities in crude glycerol can negatively affect microbial performances. In this view, the selection of the best cell factory, together with the development of a robust and effective production process are primary requirements. The present work compared crude versus pure glycerol as carbon sources for lipid production by three different oleaginous yeasts: Rhodosporidium toruloides (DSM 4444), Lipomyces starkeyi (DSM 70295) and Cryptococcus curvatus (DSM 70022). An efficient yet simple feeding strategy for avoiding the lag phase caused by growth on crude glycerol was developed, leading to high biomass and lipid production for all the tested yeasts. Flow-cytometry and fourier transform infrared (FTIR) microspectroscopy, supported by principal component analysis (PCA), were used as non-invasive and quick techniques to monitor, compare and analyze the lipid production over time. Gas chromatography (GC) analysis completed the quali-quantitative description. Under these operative conditions, the highest lipid content (up to 60.9% wt/wt) was measured in R. toruloides, while L. starkeyi showed the fastest glycerol consumption rate (1.05 g L(-1) h(-1)). Being productivity the most industrially relevant feature to be pursued, under the presented optimized conditions R. toruloides showed the best lipid productivity (0.13 and 0.15 g L(-1) h(-1) on pure and crude glycerol, respectively). Here we demonstrated that the development of an efficient feeding strategy is sufficient in preventing the inhibitory effect of crude glycerol, and robust enough to ensure high lipid

  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. Effect of laser peening with glycerol as plasma confinement layer

    Science.gov (United States)

    Tsuyama, Miho; Ehara, Naoya; Yamashita, Kazuma; Heya, Manabu; Nakano, Hitoshi

    2018-03-01

    The effects of controlling the plasma confinement layer on laser peening were investigated by measuring the hardness and residual stress of laser-peened stainless steels. The plasma confinement layer contributes to increasing the pressure of shock waves by suppressing the expansion of the laser-produced plasma. Most previous studies on laser peening have employed water as the plasma confinement layer. In this study, a glycerol solution is used in the context of a large acoustic impedance. It is found that this glycerol solution is superior to water in its ability to confine plasma and that suitable conditions exist for the glycerol solution to act as a plasma confinement layer to achieve efficient laser peening.

  17. 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

  18. A review on the performance of glycerol carbonate production via catalytic transesterification: Effects of influencing parameters

    International Nuclear Information System (INIS)

    Teng, Wai Keng; Ngoh, Gek Cheng; Yusoff, Rozita; Aroua, Mohamed Kheireddine

    2014-01-01

    Highlights: • Utilization of glycerol to synthesize glycerol carbonate through various routes. • Different types of carbonates and catalysts used for glycerol carbonate production via transesterification are elucidated. • Important factors influencing glycerol carbonate production performances are detailed. • Future research needs of glycerol carbonate production are proposed. - Abstract: Driven by high energy demand and environmental concerns, biodiesel as a substitute for fossil fuels is recognized to be promising renewable and clean energy. The increase in the biodiesel plant dramatically leads to the oversupply of its by-product glycerol in the biodiesel industries. Developing new industrial uses for glycerol is essential to increase the net energy and sustainability of biodiesel. Moreover, glycerol has great potential to be converted into marketable and valuable chemicals. The conversion of glycerol to glycerol carbonate (GC) has been extensively studied and transesterification of glycerol to GC has been proven to be the most promising route. Aimed to reveal the underlying mechanism of this successful conversion path, this paper reviews the chemo- and biocatalytic transesterification of glycerol with different carbonates sources. Also, a detail elucidation of the influence of the catalysts and operating conditions on the GC yield is included to provide an insight into the process. In addition, the future direction of glycerol carbonate production via catalytic transesterification is provided in this review

  19. 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.

  20. On the pressure dependence of the fragility of glycerol

    Energy Technology Data Exchange (ETDEWEB)

    Pawlus, S; Paluch, M; Ziolo, J [Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland); Roland, C M [Naval Research Laboratory, Chemistry Division, Code 6120, Washington, DC 20375-5342 (United States)

    2009-08-19

    This work was motivated by ostensibly contradictory results from different groups regarding the effect of pressure on the fragility of glycerol. We present new experimental data for an intermediate pressure regime showing that the fragility increases with pressure up to about 1.8 GPa, becoming invariant at higher pressures. There is no discrepancy among the various literature data taken in toto. The behavior of glycerol is quite distinct from that of normal liquids, a result of its substantial hydrogen bonding. (fast track communication)

  1. Novel high dielectric constant hybrid elastomers based on glycerol-insilicone emulsions

    DEFF Research Database (Denmark)

    Mazurek, Piotr Stanislaw; Skov, Anne Ladegaard

    2016-01-01

    Novel hybrid elastomers were prepared by speedmixing of two virtually immiscible liquids – glycerol and polydimethylsiloxane (PDMS) prepolymer. Upon crosslinking ofthe PDMS phase of the resulting glycerol-in-silicone emulsion freestanding films were obtained. In this way glycerol became uniformly...... elastomeractuators. Conductivities of samples based on various PDMS compositions with different loadings of embedded glycerol were thoroughly investigated providing useful information about the dielectric behavior....

  2. 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

  3. 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, ...

  4. 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.

  5. 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 ...

  6. Influence of hyperosmotic agent (glycerol) in contrast enhancement

    International Nuclear Information System (INIS)

    Moriyama, Takashi; Suzuki, Shigeharu; Nakaoka, Tsutomu

    1981-01-01

    For getting a better contrast enhancement (CE) of computed tomography (CT) in brain tumors, we tried to increase the extravascular iodine concentration. A vailing ourselves of the period of returning water following intravenously administered glycerol, a drip injection of the contrast medium gave a better CE effect than the usual CE. In two benign gliomas, CE with glycerol was much better than CE without glycerol, and in two malignant gliomas and two metastatic tumors, CE with glycerol was better, but not so much better as with the benign tumors. In general, the CE effect in primary brain tumors showed a decreasing pattern, whereas in metastatic brain tumors the best time was 60 minutes after the injection of the contrast material (increasing and decreasing pattern), suggesting an increase in the extravascular iodine and a severe failure of the blood brain barrier. Two cystic malignant gliomas allowed the intravenously injected contrast medium to enter the cysts. It appears that the contrast medium passes through and/or is secreted from the wall of the cyst. (author)

  7. Toxicity of palmitoyl glycerol to mice: depression of thyroid function

    International Nuclear Information System (INIS)

    Trumbo, P.R.; Meuten, D.J.; King, M.W.; Tove, S.B.

    1987-01-01

    Mice given propylthiouracil, a thyroid inhibitor, and fed a diet containing a nontoxic level of rac-1(3)-palmitoyl glycerol showed the hypothermia and mortality expected for a toxic dose, but did not show these signs when linoleate or oleate was added to the diet. Loss of radioiodine from the whole animal and thyroid gland was slower when mice were fed the toxic palmitoyl glycerol diet than when fed the same diet containing 4% safflower oil. However, mice fed the two diets did not differ in the extent of the incorporation of radioiodine, and essentially all was bound to protein in each case. Follicular thyroid cells from mice fed the potentially toxic diet that contained unsaturated fat were normal in appearance. Conversely, cells from mice fed the toxic diet were smaller and more densely stained, showing evidence of glycoprotein inside the cell. These findings show that the thyroid gland is affected by the palmitoyl glycerol diet. However, the thyroid is not the only organ affected, because giving either thyroxine or triiodothyronine had no effect on the toxicity of palmitoyl glycerol

  8. Isolation and chemical characterization of phosphatidyl glycerol from spinach leaves

    NARCIS (Netherlands)

    Haverkate, E.; Deenen, L.L.M. van

    1965-01-01

    Pure phosphatidyl glycerol was obtained from spinach leaves after repeated chromatography on silica columns. Ascertainment of the configuration of the hydrolysis products formed by the action of phospholipases C (EC 3.1.4.3) and D (EC 3.1.4.4) demonstrated that this phospholipid is identical with

  9. 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.

  10. [Long-term storage of obligate anaerobic microorganisms in glycerol].

    Science.gov (United States)

    Briukhanov, A I; Netrusov, A I

    2006-01-01

    We evaluated the possibility of storing the cultures of obligate anaerobic microorganisms (clostridia. acetogenic and sulfate-reducing bacteria, and methanogenic archaea) in 25% glycerol at -70 degrees C for a long time (up to 3 years). This method of storage is adequate to preserve cell viability in most obligate anaerobes.

  11. Liquid phase conversion of Glycerol to Propanediol over highly ...

    Indian Academy of Sciences (India)

    characterization results showed that the copper metal was well-dispersed over MgO support and a new phase. Cu-MgO was ... Currently propanediols are produced from petroleum derivatives .... of MgO.15 Barret-Joyner-Halenda (BJH) method is applied to ..... number of available Cu sites with respect to glycerol as. 0.8. 1.0.

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

    KAUST Repository

    Selembo, Priscilla A.; Perez, Joe M.; Lloyd, Wallis A.; Logan, Bruce E.

    2009-01-01

    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

  13. 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

  14. Efficient utilization of crude glycerol as fermentation substrate in the synthesis of poly(3-hydroxybutyrate) biopolymers

    Science.gov (United States)

    One refined and 2 crude glycerol samples were utilized to produce poly(3-hydroxybutyrate) (PHB) by Pseudomonas oleovorans NRRL B-14682. Fermentation conditions were determined to efficiently utilize glycerol while maintaining PHB yields. A batch culture protocol including 1% glycerol and an aerati...

  15. 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.

  16. 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.

  17. 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.

  18. Glycerol (byproduct of biodiesel production) as a source of fuels and chemicals : mini review

    Energy Technology Data Exchange (ETDEWEB)

    Fan, X.; Burton, R. [Piedmont Biofuels Industrial, Pittsboro, NC (United States); Zhou, Y. [Yonezawa Hamari Chemical, Ltd., Yonezawa, Yamagata (Japan)

    2010-07-01

    Glycerol, a byproduct of biodiesel production, is a potential renewable feedstock for the production of functional chemicals. This paper reviewed recent developments in the conversion of glycerol into value-added products, including citric acid, lactic acid, 1,3-dihydroxyacetone (DHA), 1,3-propanediol (1,3-PD), dichloro-2-propanol (DCP), acrolein, hydrogen, and ethanol. The new applications of glycerol will improve the economic viability of the biodiesel industry and capitalize on the oversupply of crude glycerol that the biodiesel industry has produced. Increasing abundance and attractive pricing make glycerol an attractive feedstock for deriving value-added chemical compounds. The processes turn glycerol into chemicals, materials, and fuels and fuel additives. Whereas glycerol from first-generation biodiesel production has low purity, glycerol from second-generation biodiesel production, which uses non-edible oil as a feedstock, produces a higher purity glycerol, minimizing the related impurity problem and potentially increasing the applications of glycerol. Glycerol is also being looked at as a carbon source for algal biomass fermentation. 36 refs.

  19. Bovine oocytes and early embryos express mRNA encoding glycerol kinase but addition of glycerol to the culture media interferes with oocyte maturation.

    Science.gov (United States)

    Okawara, Sumika; Hamano, Seizo; Tetsuka, Masafumi

    2009-04-01

    Glycerol plays multi-functional roles in cellular physiology. Other than forming the backbone molecule for glycerophospholipid and triglyceride (TG), glycerol acts as an energy substrate for glycolysis. Spermatozoa are known to utilize glycerol for energy production, but there are no reports of this in oocytes. In this study, the value of glycerol as an energy substrate for bovine oocyte maturation (Exp. 1) and the gene expression of glycerol kinase (GK), an enzyme crucial for cellular glycerol utilization, in bovine oocytes and early embryos (Exp. 2) were examined. In Exp. 1, in vitro maturation (IVM) was conducted using synthetic oviduct fluid supplemented with/without glucose (1.5 mM) and/or glycerol (1.0 mM), and maturation rate, degree of cumulus expansion, glucose consumption and lactate production by cumulus-oocyte complexes (COC) were examined. In Exp. 2, to examine the developmental expression of GK mRNA, cumulus cells, oocytes and embryos at the 2-, 8- and 16-cell, morula, expanded blastocyst and hatched blastocyst stages were obtained in separate experiments, and the expression of GK mRNA was quantified using a real-time PCR. Glycerol did not support oocyte maturation or cumulus expansion. Addition of glycerol to glucose-supplemented media significantly decreased the maturation rate. Expression of GK mRNA was very low in cumulus cells, whereas an appreciable level of the transcript was observed in the oocytes. GK mRNA was detected in embryos at all the stages examined, and its expression significantly increased at the morula stage. These results indicate that glycerol, at least at the present concentration, is not beneficial as a constituent of the medium for bovine oocyte maturation. However, the appreciable levels of GK mRNA found in the oocyte and embryo imply a physiological role for glycerol in bovine oocyte maturation and embryo development.

  20. 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%.

  1. 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.

  2. 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....

  3. Glycerol and microwave preservation of annual statice (Limonium sinuatum Mill.)

    International Nuclear Information System (INIS)

    Paparozzi, E.T.; McCallister, D.E.

    1988-01-01

    Stems of annual statice (Limonium sinuatum Mill.) were harvested from the field in 1982 and soaked in varying concentrations of glycerol: water solutions for 24 and 48 h and then microwaved for 0, 1, 3 or 5 min. Half of the branch stems were measured for flexibility, with the remainder being assessed 1 year later. Stems harvested in 1983 were wet- and dry-stored at 3°C for varying lengths of time and then preserved. Preservation was best when statice was preserved immediately. Cold storage decreased preserved statice flexibility, but was better than air-drying. Fresh cut statice stems, up to 34 cm long, should be preserved by soaking in a 1:2 or 1:3 glycerol: water solution for 48 h followed by microwaving for 1 min at medium-high (34°C)

  4. Modified silica-based heterogeneous catalysts for etherification of glycerol

    International Nuclear Information System (INIS)

    Gholami, Zahra; Abdullah, Ahmad Zuhairi; Gholami, Fatemeh; Vakili, Mohammadtaghi

    2015-01-01

    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 1.6 La 0.6 /MCM-41 catalyst resulted in the highest glycerol conversion of 91% and diglycerol yield of 43%

  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. 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...

  7. 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

  8. Provenance of tetraether membrane lipids in a large temperate lake (Loch Lomond, UK): implications for glycerol dialkyl glycerol tetraether (GDGT)-based palaeothermometry

    NARCIS (Netherlands)

    Buckles, L.K.; Weijers, J.W.H.; Tran, X.-M.; Waldron, S.; Sinninghe Damsté, J.S.

    2014-01-01

    The application of glycerol dialkyl glycerol tetraether (GDGT)-based palaeoenvironmental proxies, such as the branched vs. isoprenoidal tetratether (BIT) index, TEX86 and the MBT–CBT palaeothermometer, has lately been expanded to lacustrine sediments. Given recent research identifying the production

  9. Provenance of tetraether membrane lipids in a large temperate lake (Loch Lomond, UK) : Implications for glycerol dialkyl glycerol tetraether (GDGT)-based palaeothermometry

    NARCIS (Netherlands)

    Buckles, L. K.; Weijers, J. W H; Tran, X.-M.; Waldron, S.; Sinninghe Damsté, J. S.

    2014-01-01

    The application of glycerol dialkyl glycerol tetraether (GDGT)-based palaeoenvironmental proxies, such as the branched vs. isoprenoidal tetratether (BIT) index, TEX86 and the MBT-CBT palaeothermometer, has lately been expanded to lacustrine sediments. Given recent research identifying the production

  10. 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

  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. 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

  13. 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.

  14. A specific glycerol kinase induces rapid cold hardening of the diamondback moth, Plutella xylostella.

    Science.gov (United States)

    Park, Youngjin; Kim, Yonggyun

    2014-08-01

    Insects in temperate zones survive low temperatures by migrating or tolerating the cold. The diamondback moth, Plutella xylostella, is a serious insect pest on cabbage and other cruciferous crops worldwide. We showed that P. xylostella became cold-tolerant by expressing rapid cold hardiness (RCH) in response to a brief exposure to moderately low temperature (4°C) for 7h along with glycerol accumulation in hemolymph. Glycerol played a crucial role in the cold-hardening process because exogenously supplying glycerol significantly increased the cold tolerance of P. xylostella larvae without cold acclimation. To determine the genetic factor(s) responsible for RCH and the increase of glycerol, four glycerol kinases (GKs), and glycerol-3-phosphate dehydrogenase (PxGPDH) were predicted from the whole P. xylostella genome and analyzed for their function associated with glycerol biosynthesis. All predicted genes were expressed, but differed in their expression during different developmental stages and in different tissues. Expression of the predicted genes was individually suppressed by RNA interference (RNAi) using double-stranded RNAs specific to target genes. RNAi of PxGPDH expression significantly suppressed RCH and glycerol accumulation. Only PxGK1 among the four GKs was responsible for RCH and glycerol accumulation. Furthermore, PxGK1 expression was significantly enhanced during RCH. These results indicate that a specific GK, the terminal enzyme to produce glycerol, is specifically inducible during RCH to accumulate the main cryoprotectant. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Molecular packing, hydrogen bonding, and fast dynamics in lysozyme/trehalose/glycerol and trehalose/glycerol glasses at low hydration

    OpenAIRE

    Lerbret, Adrien; Affouard, Frédéric

    2017-01-01

    Water and glycerol are well-known to facilitate the structural relaxation of amorphous protein matrices. However, several studies evidenced that they may also limit fast ($\\sim$ pico-nanosecond, ps-ns) and small-amplitude ($\\sim$ \\AA ) motions of proteins, which govern their stability in freeze-dried sugar mixtures. To determine how they interact with proteins and sugars in glassy matrices and, thereby, modulate their fast dynamics, we performed molecular dynamics (MD) simulations of lysozyme...

  16. 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

    dehydrogenase encoding region of the bacterium, or is inserted into a phosphotransacetylase encoding region of the bacterium, or is inserted into an acetate kinase encoding region of the bacterium. It is operably linked to an inducible, a regulated or a constitutive promoter. The up-regulated glycerol......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...... glycerol dehydrogenase; and/or (ii) up-regulating a native gene encoding glycerol dehydrogenase; and (b) obtaining the recombinant bacterium. Preferred Bacterium: In the recombinant bacterium above, the inserted heterologous gene and/or the up-regulated native gene is encoding a glycerol dehydrogenase...

  17. Impact of impurities in biodiesel-derived crude glycerol on the fermentation by Clostridium pasteurianum ATCC 6013

    Energy Technology Data Exchange (ETDEWEB)

    Venkataramanan, Keerthi P.; Boatman, Judy J.; Taconi, Katherine A. [Alabama Univ., Huntsville, AL (United States). Dept. of Chemical and Materials Engineering; Kurniawan, Yogi; Bothun, Geoffrey D. [Rhode Island Univ., Kingston, RI (United States). Dept. of Chemical Engineering; Scholz, Carmen [Alabama Univ., Huntsville, AL (United States). Dept. of Chemistry

    2012-02-15

    During the production of biodiesel, crude glycerol is produced as a byproduct at 10% (w/w). Clostridium pasteurianum has the inherent potential to grow on glycerol and produce 1,3-propanediol and butanol as the major products. Growth and product yields on crude glycerol were reported to be slower and lower, respectively, in comparison to the results obtained from pure glycerol. In this study, we analyzed the effect of each impurity present in the biodiesel-derived crude glycerol on the growth and metabolism of glycerol by C. pasteurianum. The crude glycerol contains methanol, salts (in the form of potassium chloride or sulfate), and fatty acids that were not transesterified. Salt and methanol were found to have no negative effects on the growth and metabolism of the bacteria on glycerol. The fatty acid with a higher degree of unsaturation, linoleic acid, was found to have strong inhibitory effect on the utilization of glycerol by the bacteria. The fatty acid with lower or no degrees of unsaturation such as stearic and oleic acid were found to be less detrimental to substrate utilization. The removal of fatty acids from crude glycerol by acid precipitation resulted in a fermentation behavior that is comparable to the one on pure glycerol. These results show that the fatty acids in the crude glycerol have a negative effect by directly affecting the utilization of glycerol as the carbon source, and hence their removal from crude glycerol is an essential step towards the utilization of crude glycerol. (orig.)

  18. Cellulose-glycerol-polyvinyl alcohol composite films for food packaging: Evaluation of water adsorption, mechanical properties, light-barrier properties and transparency.

    Science.gov (United States)

    Cazón, Patricia; Vázquez, Manuel; Velazquez, Gonzalo

    2018-09-01

    Nowadays consumers are aware of environmental problems. As an alternative to petrochemical polymers for food packaging, researchers have been focused on biopolymeric materials as raw material. The aim of this study was to evaluate mechanical properties (toughness, burst strength and distance to burst), water adsorption, light-barrier properties and transparency of composite films based on cellulose, glycerol and polyvinyl alcohol. Scanning electron microscopy, spectral analysis (FT-IR and UV-VIS-NIR) and differential scanning calorimetry were performed to explain the morphology, structural and thermal properties of the films. Results showed that polyvinyl alcohol enhances the toughness of films up to 44.30 MJ/m 3 . However, toughness decreases when glycerol concentration is increased (from 23.41 to 10.55 MJ/m 3 ). Water adsorption increased with increasing polyvinyl alcohol concentration up to 222%. Polyvinyl alcohol increased the film thickness. The films showed higher burst strength (up to 12014 g) than other biodegradable films. The films obtained have optimal values of transparency like those values of synthetic polymers. Glycerol produced a UV protective effect in the films, an important effect for food packaging to prevent lipid oxidative deterioration. Results showed that it is feasible to obtain cellulose-glycerol-polyvinyl alcohol composite films with improved properties. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. Engineering an Obligate Photoautotrophic Cyanobacterium to Utilize Glycerol for Growth and Chemical Production.

    Science.gov (United States)

    Kanno, Masahiro; Atsumi, Shota

    2017-01-20

    Cyanobacteria have attracted much attention as a means to directly recycle carbon dioxide into valuable chemicals that are currently produced from petroleum. However, the titers and productivities achieved are still far below the level required in industry. To make a more industrially applicable production scheme, glycerol, a byproduct of biodiesel production, can be used as an additional carbon source for photomixotrophic chemical production. Glycerol is an ideal candidate due to its availability and low cost. In this study, we found that a heterologous glycerol respiratory pathway enabled Synechococcus elongatus PCC 7942 to utilize extracellular glycerol. The engineered strain produced 761 mg/L of 2,3-butanediol in 48 h with a 290% increase over the control strain under continuous light conditions. Glycerol supplementation also allowed for continuous cell growth and 2,3-butanediol production in diurnal light conditions. These results highlight the potential of glycerol as an additional carbon source for photomixotrophic chemical production in cyanobacteria.

  20. 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

    glycerol uptake was observed, which was substantially higher during exercise. Total body skeletal muscle FA and glycerol uptake/release was estimated to account for 18-25 % of whole body R(d) or R(a). In conclusion: (1) skeletal muscle FA and glycerol metabolism, using the leg arterial-venous difference......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...

  1. Valorization of glycerol through the production of biopolymers: the PHB case using Bacillus megaterium.

    Science.gov (United States)

    Naranjo, Javier M; Posada, John A; Higuita, Juan C; Cardona, Carlos A

    2013-04-01

    In this work technical and economic analyses were performed to evaluate the glycerol transformation into Polyhydroxybutyrate using Bacillus megaterium. The production of PHB was compared using glycerol or glucose as substrates and similar yields were obtained. The total production costs for PHB generation with both substrates were estimated at an industrial scale. Compared to glucose, glycerol showed a 10% and 20% decrease in the PHB production costs using two different separation schemes respectively. Moreover, a 20% profit margin in the PHB sales price using glycerol as substrate resulted in a 166% valorization of crude glycerol. In this work, the feasibility of glycerol as feedstock for the production of PHB at laboratory (up to 60% PHB accumulation) and industrial (2.6US$/kgPHB) scales is demonstrated. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Bioconversion of glycerol for bioethanol production using isolated Escherichia coli SS1

    Directory of Open Access Journals (Sweden)

    Sheril Norliana Suhaimi

    2012-06-01

    Full Text Available Bioconverting glycerol into various valuable products is one of glycerol's promising applications due to its high availability at low cost and the existence of many glycerol-utilizing microorganisms. Bioethanol and biohydrogen, which are types of renewable fuels, are two examples of bioconverted products. The objectives of this study were to evaluate ethanol production from different media by local microorganism isolates and compare the ethanol fermentation profile of the selected strains to use of glucose or glycerol as sole carbon sources. The ethanol fermentations by six isolates were evaluated after a preliminary screening process. Strain named SS1 produced the highest ethanol yield of 1.0 mol: 1.0 mol glycerol and was identified as Escherichia coli SS1 Also, this isolated strain showed a higher affinity to glycerol than glucose for bioethanol production.

  3. 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.

  4. 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....

  5. 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.

  6. Dietary Tools To Modulate Glycogen Storage in Gilthead Seabream Muscle: Glycerol Supplementation

    DEFF Research Database (Denmark)

    Silva, Tomé S.; Matos, Elisabete; Cordeiro, Odete D.

    2012-01-01

    The quality and shelf life of fish meat products depend on the skeletal muscle’s energetic state at slaughter, as meat decomposition processes can be exacerbated by energy depletion. In this study, we tested dietary glycerol as a way of replenishing muscle glycogen reserves of farmed gilthead......, and organoleptic properties (aroma and color). Proteomic analysis showed a low impact of glycerol-supplementation on muscle metabolism, with most changes probably reflecting increased stress coping capacity in glycerol-fed fish. This suggests inclusion of crude glycerol in gilthead seabream diets (particularly...

  7. Engineering of the glycerol decomposition pathway and cofactor regulation in an industrial yeast improves ethanol production.

    Science.gov (United States)

    Zhang, Liang; Tang, Yan; Guo, Zhongpeng; Shi, Guiyang

    2013-10-01

    Glycerol is a major by-product of industrial ethanol production and its formation consumes up to 4 % of the sugar substrate. This study modified the glycerol decomposition pathway of an industrial strain of Saccharomyces cerevisiae to optimize the consumption of substrate and yield of ethanol. This study is the first to couple glycerol degradation with ethanol formation, to the best of our knowledge. The recombinant strain overexpressing GCY1 and DAK1, encoding glycerol dehydrogenase and dihydroxyacetone kinase, respectively, in glycerol degradation pathway, exhibited a moderate increase in ethanol yield (2.9 %) and decrease in glycerol yield (24.9 %) compared to the wild type with the initial glucose concentration of 15 % under anaerobic conditions. However, when the mhpF gene, encoding acetylating NAD⁺-dependent acetaldehyde dehydrogenase from Escherichia coli, was co-expressed in the aforementioned recombinant strain, a further increase in ethanol yield by 5.5 % and decrease in glycerol yield by 48 % were observed for the resultant recombinant strain GDMS1 when acetic acid was added into the medium prior to inoculation compared to the wild type. The process outlined in this study which enhances glycerol consumption and cofactor regulation in an industrial yeast is a promising metabolic engineering strategy to increase ethanol production by reducing the formation of glycerol.

  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...... 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...

  9. Ammonia control and neurocognitive outcome among urea cycle disorder patients treated with glycerol phenylbutyrate.

    Science.gov (United States)

    Diaz, George A; Krivitzky, Lauren S; Mokhtarani, Masoud; Rhead, William; Bartley, James; Feigenbaum, Annette; Longo, Nicola; Berquist, William; Berry, Susan A; Gallagher, Renata; Lichter-Konecki, Uta; Bartholomew, Dennis; Harding, Cary O; Cederbaum, Stephen; McCandless, Shawn E; Smith, Wendy; Vockley, Gerald; Bart, Stephen A; Korson, Mark S; Kronn, David; Zori, Roberto; Merritt, J Lawrence; C S Nagamani, Sandesh; Mauney, Joseph; Lemons, Cynthia; Dickinson, Klara; Moors, Tristen L; Coakley, Dion F; Scharschmidt, Bruce F; Lee, Brendan

    2013-06-01

    Glycerol phenylbutyrate is under development for treatment of urea cycle disorders (UCDs), rare inherited metabolic disorders manifested by hyperammonemia and neurological impairment. We report the results of a pivotal Phase 3, randomized, double-blind, crossover trial comparing ammonia control, assessed as 24-hour area under the curve (NH3 -AUC0-24hr ), and pharmacokinetics during treatment with glycerol phenylbutyrate versus sodium phenylbutyrate (NaPBA) in adult UCD patients and the combined results of four studies involving short- and long-term glycerol phenylbutyrate treatment of UCD patients ages 6 and above. Glycerol phenylbutyrate was noninferior to NaPBA with respect to ammonia control in the pivotal study, with mean (standard deviation, SD) NH3 -AUC0-24hr of 866 (661) versus 977 (865) μmol·h/L for glycerol phenylbutyrate and NaPBA, respectively. Among 65 adult and pediatric patients completing three similarly designed short-term comparisons of glycerol phenylbutyrate versus NaPBA, NH3 -AUC0-24hr was directionally lower on glycerol phenylbutyrate in each study, similar among all subgroups, and significantly lower (P < 0.05) in the pooled analysis, as was plasma glutamine. The 24-hour ammonia profiles were consistent with the slow-release behavior of glycerol phenylbutyrate and better overnight ammonia control. During 12 months of open-label glycerol phenylbutyrate treatment, average ammonia was normal in adult and pediatric patients and executive function among pediatric patients, including behavioral regulation, goal setting, planning, and self-monitoring, was significantly improved. Glycerol phenylbutyrate exhibits favorable pharmacokinetics and ammonia control relative to NaPBA in UCD patients, and long-term glycerol phenylbutyrate treatment in pediatric UCD patients was associated with improved executive function (ClinicalTrials.gov NCT00551200, NCT00947544, NCT00992459, NCT00947297). (HEPATOLOGY 2012). Copyright © 2012 American Association for the

  10. 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

  11. 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.

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

    KAUST Repository

    Selembo, Priscilla A.; Perez, Joe M.; Lloyd, Wallis A.; Logan, Bruce E.

    2009-01-01

    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

  13. 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

  14. 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.

  15. Co-digestion of sewage sludge with glycerol to boost biogas production

    International Nuclear Information System (INIS)

    Fountoulakis, M.S.; Petousi, I.; Manios, T.

    2010-01-01

    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 o 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 (μ 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.

  16. Conversion of the biodiesel by-product glycerol by the non-conventional yeast Pachysolen tannophilus

    DEFF Research Database (Denmark)

    Liu, Xiaoying

    production process. Since the volume of the glycerol by-product has exceeded the current market need, biodiesel producers are looking for new methods for sustainable glycerol management and improving the competitiveness of the biodiesel industries. The EU Commission funded GLYFINERY project is one initiative...

  17. Microstructure and molecular interaction in glycerol plasticized chitosan/poly(vinyl alcohol) blending films

    Science.gov (United States)

    Poly (vinyl alcohol) (PVA)/chitosan (CS) blended films plasticized by glycerol were investigated using mechanical testing, atomic force microscopy (AFM), differential scanning calorimetry (DSC) and FTIR spectroscopy, with primary emphasis on the effects of the glycerol content and the molecular weig...

  18. Utilization of Crude Glycerol as a Substrate for the Production of Rhamnolipid by Pseudomonas aeruginosa.

    Science.gov (United States)

    Eraqi, Walaa A; Yassin, Aymen S; Ali, Amal E; Amin, Magdy A

    2016-01-01

    Biosurfactants are produced by bacteria or yeast utilizing different substrates as sugars, glycerol, or oils. They have important applications in the detergent, oil, and pharmaceutical industries. Glycerol is the product of biodiesel industry and the existing glycerol market cannot accommodate the excess amounts generated; consequently, new markets for refined glycerol need to be developed. The aim of present work is to optimize the production of microbial rhamnolipid using waste glycerol. We have developed a process for the production of rhamnolipid biosurfactants using glycerol as the sole carbon source by a local Pseudomonas aeruginosa isolate that was obtained from an extensive screening program. A factorial design was applied with the goal of optimizing the rhamnolipid production. The highest production yield was obtained after 2 days when cells were grown in minimal salt media at pH 6, containing 1% (v/v) glycerol and 2% (w/v) sodium nitrate as nitrogen source, at 37°C and at 180 rpm, and reached 2.164 g/L after 54 hours (0.04 g/L h). Analysis of the produced rhamnolipids by TLC, HPLC, and FTIR confirmed the nature of the biosurfactant as monorhamnolipid. Glycerol can serve as a source for the production of rhamnolipid from microbial isolates providing a cheap and reliable substrate.

  19. 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

  20. 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

  1. 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...

  2. 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

  3. Upgrading Fast Pyrolysis Oil via Hydrodeoxygenation and Thermal Treatment: Effects of Catalytic Glycerol Pretreatment

    NARCIS (Netherlands)

    Reyhanitash, Ehsan; Tymchyshyn, M.; Yuan, Zhongshun; Albion, K.; van Rossum, G.; Xu, C.

    2014-01-01

    The effects of stabilizing fast pyrolysis oil (PO) with glycerol via catalytic glycerol pretreatment on upgrading via hydrodeoxygenation (HDO) or thermal treatment (TT) were studied. Nonstabilized (original) fast pyrolysis oil was also upgraded via HDO or TT to obtain benchmarks. Generally, HDO

  4. 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...

  5. Sequential spectrofluorimetric determination of free and total glycerol in biodiesel in a multicommuted flow system

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Sidnei G. [Universidade de Sao Paulo, Instituto de Quimica, Sao Paulo (Brazil); Morales-Rubio, Angel; Guardia, Miguel de la [Universidad de Valencia, Department of Analytical Chemistry, Burjassot, Valencia (Spain); Rocha, Fabio R.P. [Universidade de Sao Paulo, Centro de Energia Nuclear na Agricultura, Piracicaba (Brazil)

    2011-07-15

    A new procedure for spectrofluorimetric determination of free and total glycerol in biodiesel samples is presented. It is based on the oxidation of glycerol by periodate, forming formaldehyde, which reacts with acetylacetone, producing the luminescent 3,5-diacetyl-1,4-dihydrolutidine. A flow system with solenoid micro-pumps is proposed for solution handling. Free glycerol was extracted off-line from biodiesel samples with water, and total glycerol was converted to free glycerol by saponification with sodium ethylate under sonication. For free glycerol, a linear response was observed from 5 to 70 mg L{sup -1} with a detection limit of 0.5 mg L{sup -1}, which corresponds to 2 mg kg{sup -1} in biodiesel. The coefficient of variation was 0.9% (20 mg L{sup -1}, n = 10). For total glycerol, samples were diluted on-line, and the linear response range was 25 to 300 mg L{sup -1}. The detection limit was 1.4 mg L{sup -1} (2.8 mg kg{sup -1} in biodiesel) with a coefficient of variation of 1.4% (200 mg L{sup -1}, n = 10). The sampling rate was ca. 35 samples h{sup -1} and the procedure was applied to determination of free and total glycerol in biodiesel samples from soybean, cottonseed, and castor beans. (orig.)

  6. 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

  7. Ethanol production from biodiesel-derived crude glycerol by newly isolated Kluyvera cryocrescens

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Won Jae; Hartono, Maria Regina; Chan, Weng Heng; Yeo, Suan Siong [Agency for Science, Technology and Research (A*STAR), Jurong Island (Singapore). Inst. of Chemical and Engineering Sciences

    2011-02-15

    The rapidly expanding market for biodiesel has increased the supply and reduced the cost of glycerol, making it an attractive sustainable feed stock for the fuel and chemical industry. Glycerol-based biorefinery is the microbial fermentation of crude glycerol to produce fuels and chemicals. A major challenge is to obtain microbes tolerant to inhibitors such as salts and organic solvents present in crude glycerol. Microbial screening was attempted to isolate novel strain capable of growing on crude glycerol as a sole carbon source. The newly isolated bacteria, identified as nonpathogenic Kluyvera cryocrescens S26 could convert biodiesel-derived crude glycerol to ethanol with high yield and productivity. The supplementation of nutrients such as yeast extract resulted in distinguished enhancement in cell growth as well as ethanol productivity under anaerobic condition. When glycerol fermentation is performed under microaerobic condition, there is also a remarkable improvement in cell growth, ethanol productivity and yield, compared with those under strict anaerobic condition. In batch fermentation under microaerobic condition, K. cryocrescens S26 produced 27 g/l of ethanol from crude glycerol with high molar yield of 80% and productivity of 0.61 g/l/h. (orig.)

  8. 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...

  9. Inhibitory Effect Evaluation of Glycerol-Iron Oxide Thin Films on Methicillin-Resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    C. L. Popa

    2015-01-01

    Full Text Available The main purpose of this study was to evaluate the inhibitory effect of glycerol- iron oxide thin films on Methicillin-Resistant Staphylococcus aureus (MRSA. Our results suggest that glycerol-iron oxide thin films could be used in the future for various biomedical and pharmaceutical applications. The glycerol-iron oxide thin films have been deposited by spin coating method on a silicon (111 substrate. The structural properties have been studied by X-ray diffraction (XRD and scanning electron spectroscopy (SEM. The XRD investigations of the prepared thin films demonstrate that the crystal structure of glycerol-iron oxide nanoparticles was not changed after spin coating deposition. On the other hand, the SEM micrographs suggest that the size of the glycerol-iron oxide microspheres increased with the increase of glycerol exhibiting narrow size distributions. The qualitative depth profile of glycerol-iron oxide thin films was identified by glow discharge optical emission spectroscopy (GDOES. The GDOES spectra revealed the presence of the main elements: Fe, O, C, H, and Si. The antimicrobial activity of glycerol-iron oxide thin films was evaluated by measuring the zone of inhibition. After 18 hours of incubation at 37°C, the diameters of the zones of complete inhibition have been measured obtaining values around 25 mm.

  10. Glycerol metabolism induces Listeria monocytogenes biofilm formation at the air-liquid interface.

    Science.gov (United States)

    Crespo Tapia, Natalia; den Besten, Heidy M W; Abee, Tjakko

    2018-05-20

    Listeria monocytogenes is a food-borne pathogen that can grow as a biofilm on surfaces. Biofilm formation in food-processing environments is a big concern for food safety, as it can cause product contamination through the food-processing line. Although motile aerobic bacteria have been described to form biofilms at the air-liquid interface of cell cultures, to our knowledge, this type of biofilm has not been described in L. monocytogenes before. In this study we report L. monocytogenes biofilm formation at the air-liquid interface of aerobically grown cultures, and that this phenotype is specifically induced when the media is supplemented with glycerol as a carbon and energy source. Planktonic growth, metabolic activity assays and HPLC measurements of glycerol consumption over time showed that glycerol utilization in L. monocytogenes is restricted to growth under aerobic conditions. Gene expression analysis showed that genes encoding the glycerol transporter GlpF, the glycerol kinase GlpK and the glycerol 3-phosphate dehydrogenase GlpD were upregulated in the presence of oxygen, and downregulated in absence of oxygen. Additionally, motility assays revealed the induction of aerotaxis in the presence of glycerol. Our results demonstrate that the formation of biofilms at the air-liquid interface is dependent on glycerol-induced aerotaxis towards the surface of the culture, where L. monocytogenes has access to higher concentrations of oxygen, and is therefore able to utilize this compound as a carbon source. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. 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...

  12. Flow cytometric viability assessment and transmission electron microscopic morphological study of Bacteria in Glycerol

    NARCIS (Netherlands)

    Saegeman, V.S.M.; Vos, de R.; Tebaldi, N.D.; Wolf, van der J.M.; Bergervoet, J.H.W.; Verhaegen, J.; Lismont, D.; Verduyckt, B.; Ectors, N.L.

    2007-01-01

    Human cadaveric skin allografts are used in the treatment of burns and can be preserved in glycerol at high concentrations. Previously, glycerol has been attributed some antimicrobial effect. In an experimental set-up, we aimed at investigating this effect of prolonged incubation of bacteria in 85%

  13. 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 ...

  14. 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.

  15. 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.

  16. 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

  17. Modeling, Simulation and Optimization of Hydrogen Production Process from Glycerol using Steam Reforming

    International Nuclear Information System (INIS)

    Park, Jeongpil; Cho, Sunghyun; Kim, Tae-Ok; Shin, Dongil; Lee, Seunghwan; Moon, Dong Ju

    2014-01-01

    For improved sustainability of the biorefinery industry, biorefinery-byproduct glycerol is being investigated as an alternate source for hydrogen production. This research designs and optimizes a hydrogen-production process for small hydrogen stations using steam reforming of purified glycerol as the main reaction, replacing existing processes relying on steam methane reforming. Modeling, simulation and optimization using a commercial process simulator are performed for the proposed hydrogen production process from glycerol. The mixture of glycerol and steam are used for making syngas in the reforming process. Then hydrogen are produced from carbon monoxide and steam through the water-gas shift reaction. Finally, hydrogen is separated from carbon dioxide using PSA. This study shows higher yield than former U.S.. DOE and Linde studies. Economic evaluations are performed for optimal planning of constructing domestic hydrogen energy infrastructure based on the proposed glycerol-based hydrogen station

  18. Influence of crude glycerol on the biomass and lipid content of microalgae

    International Nuclear Information System (INIS)

    Choi, Hee-Jeong; Yu, Sung-Whan

    2015-01-01

    The growth of the algae Chlorella vulgaris, Botryococcus braunii and Scenedesmus sp. under mixotrophic conditions in the presence of different concentrations of crude glycerol was evaluated with the objective of increasing the biomass growth and algal oil content. A high biomass concentration was characteristic of these strains when grown on crude glycerol compared to autotrophic growth, and 5 g/L glycerol yielded the highest biomass concentration for these strains. Mixotrophic conditions improved both the growth of the microalgae and the accumulation of triacylglycerols (TAGs). The maximum amount of TAGs in the algae biomass was obtained in the 5 g/L glycerol growth medium. The fatty acid profiles of the oil for the cultures met the necessary requirements and the strains are promising resources for biofuel production. Keywords: biomass; glycerol; microalgae; mixotrophic; oil content

  19. 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)

  20. 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.

  1. 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)

  2. 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 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.

  3. Glycerol as Precursor of Organoselanyl and Organotellanyl Alkynes.

    Science.gov (United States)

    Lenardão, Eder J; Borges, Elton L; Stach, Guilherme; Soares, Liane K; Alves, Diego; Schumacher, Ricardo F; Bagnoli, Luana; Marini, Francesca; Perin, Gelson

    2017-03-02

    Herein we describe the synthesis of organoselanyl and organotellanyl alkynes by the addition of lithium alkynylchalcogenolate (Se and Te) to tosyl solketal, easily obtained from glycerol. The alkynylchalcogenolate anions were generated in situ and added to tosyl solketal in short reaction times, furnishing in all cases the respective products of substitution in good yields. Some of the prepared compounds were deprotected using an acidic resin to afford new water-soluble 3-organotellanylpropane-1,2-diols. The synthetic versatility of the new chalcogenyl alkynes was demonstrated in the iodocyclization of 2,2-dimethyl-1,3-dioxolanylmethyl(2-methoxyphenylethynyl)selane 3f , which afforded 3-iodo-2-(2,2-dimethyl-1,3-dioxolanylmethyl) selenanylbenzo[ b ]furan in 85% yield, opening a new way to access water-soluble Se-functionalized benzo[ b ]furanes.

  4. Molecular dynamics simulations of glycerol glass-forming liquid

    International Nuclear Information System (INIS)

    Blieck, J.; Affouard, F.; Bordat, P.; Lerbret, A.; Descamps, M.

    2005-01-01

    Structural and dynamical properties of liquid glycerol have been investigated by Molecular Dynamics simulations. An improved model based on a slight reparametrisation of the all-atoms AMBER force field used in [R. Chelli, P. Procacci, G. Cardini, R.G.D. Valle, S. Califano, Phys. Chem. Chem. Phys. 1 (1999) 871] is presented. The structure remains satisfactory, qualitatively similar to that obtained from the original model. This new model is also found to reproduce significantly better the diffusion coefficient and the correlations times as they can be deduced from neutron spin echo (NSE) experiments. Structural heterogeneities revealed as a pre-peak of the static structure factor S(Q) close to Q ∼ 0.6 A -1 are observed. Our results are also found compatible with predictions of the Mode Coupling Theory

  5. Suppression of NaNO3 crystal nucleation by glycerol: micro-Raman observation on the efflorescence process of mixed glycerol/NaNO3/water droplets.

    Science.gov (United States)

    Yu, Jun-Ying; Zhang, Yun; Zeng, Guang; Zheng, Chuan-Ming; Liu, Yong; Zhang, Yun-Hong

    2012-02-09

    Although the hygroscopicity of a NaNO(3)/water microdroplet and a polyalcohol/water microdroplet, two of the most important aerosols in atmosphere, has been widely studied, little is known about the relationship between the hygroscopic behavior of mixed NaNO(3)/polyalcohol/water droplets and their structures on the molecular level. In this study, the hygroscopicity of mixed glycerol/NaNO(3)/water droplets deposited on a hydrophobic substrate was studied by micro-Raman spectroscopy with organic-to-inorganic molar ratios (OIRs) of 0.5, 1, and 2. In the mixed glycerol/NaNO(3)/water droplets, glycerol molecules tended to combine with Na(+) and NO(3)(-) ions by electrostatic interaction and hydrogen bonding, respectively. On the basis of the analyses of the changes of symmetric stretching (v(s)-CH(2)), asymmetric stretching (v(a)-CH(2)), their area ratio (Av(a)-CH(2)/Av(s)-CH(2)) of glycerol, and symmetric stretching band of NO(3)(-) (ν(1)-NO(3)(-)) with relative humidity (RH), it was found that the conformation of glycerol was transformed from αα mainly to γγ and partly to αγ with a decreasing RH in the mixed droplets, contrary to the case in the glycerol/water droplet. In addition, the glycerol with γγ and αγ conformation had strong interaction with Na(+) and NO(3)(-) respectively, which suppressed the formation of contact of ions and delayed the efflorescence relative humidity (ERH) for the mixed droplets compared to the NaNO(3)/water droplet. © 2012 American Chemical Society

  6. Bio-hydrogen production from glycerol by a strain of Enterobacter aerogenes

    Energy Technology Data Exchange (ETDEWEB)

    Marques, P.A.S.S; Bartolomeu, M.L.; Tome, M.M.; Rosa, M.F. [INETI, Unit of Biomass/Renewable Energy Department, Estrada do Paco do Lumiar, 22, 1649-038 Lisboa (Portugal)

    2008-07-01

    The goal of this work was to evaluate the H2 production from glycerol-containing byproducts obtained from biodiesel industrial production, using Enterobacter aerogenes ATCC 13048 Sputum. H2 production using as substrate pure glycerol and glycerol-containing biodiesel byproducts was compared. The effect of parameters such as initial substrate concentration and sodium chloride addition on the bio-hydrogen production efficiency was also investigated. The results showed that using 10 g/L of pure glycerol or biodiesel residues, containing the same concentration of glycerol as substrate, lead to similar bio-hydrogen productions (3.46 LH2/L and 3.28 LH2/L fermentation medium, respectively). This indicates that the performance of the E. aerogenes strain used was not influenced by the presence of other components than glycerol in biodiesel residues, at least for the tested waste concentration range. When sodium chloride was added to the fermentation medium with pure 10 g/L glycerol, H2 production was not affected (3.34 LH2/L fermentation medium), showing that metabolism of the E. aerogenes strain was not inhibited by this biodiesel waste component up to 4 g/L chloride concentration. Biodiesel residues used without sterilization provided a higher H2 production (1.03 L) than the ones submitted to previous sterilization in autoclave (0.89 L).

  7. 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.

  8. Systematic Engineering of Escherichia coli for d-Lactate Production from Crude Glycerol.

    Science.gov (United States)

    Wang, Zei Wen; Saini, Mukesh; Lin, Li-Jen; Chiang, Chung-Jen; Chao, Yun-Peng

    2015-11-04

    Crude glycerol resulting from biodiesel production is an abundant and renewable resource. However, the impurities in crude glycerol usually make microbial fermentation problematic. This issue was addressed by systematic engineering of Escherichia coli for the production of d-lactate from crude glycerol. First, mgsA and the synthetic pathways of undesired products were eliminated in E. coli, rendering the strain capable of homofermentative production of optically pure d-lactate. To direct carbon flux toward d-lactate, the resulting strain was endowed with an enhanced expression of glpD-glpK in the glycerol catabolism and of a heterologous gene encoding d-lactate dehydrogenase. Moreover, the strain was evolved to improve its utilization of cruder glycerol and subsequently equipped with the FocA channel to export intracellular d-lactate. Finally, the fed-batch fermentation with two-phase culturing was carried out with a bioreactor. As a result, the engineered strain enabled production of 105 g/L d-lactate (99.9% optical purity) from 121 g/L crude glycerol at 40 h. The result indicates the feasibility of our approach to engineering E. coli for the crude glycerol-based fermentation.

  9. A population study of urine glycerol concentrations in elite athletes competing in North America.

    Science.gov (United States)

    Kelly, Brian N; Madsen, Myke; Sharpe, Ken; Nair, Vinod; Eichner, Daniel

    2013-01-01

    Glycerol is an endogenous substance that is on the World Anti-Doping Agency's list of prohibited threshold substances due to its potential use as a plasma volume expansion agent. The WADA has set the threshold for urine glycerol, including measurement uncertainty, at 1.3 mg/mL. Glycerol in circulation largely comes from metabolism of triglycerides in order to meet energy requirements and when the renal threshold is eclipsed, glycerol is excreted into urine. In part due to ethnic differences in postprandial triglyceride concentrations, we investigated urine glycerol concentrations in a population of elite athletes competing in North America and compared the results to those of athletes competing in Europe. 959 urine samples from elite athletes competing in North America collected for anti-doping purposes were analyzed for urine glycerol concentrations by a gas chromatography mass-spectrometry method. Samples were divided into groups according to: Timing (in- or out-of-competition), Class (strength, game, or endurance sports) and Gender. 333 (34.7%) samples had undetectable amounts of glycerol (sport classes. Copyright © 2013 John Wiley & Sons, Ltd.

  10. Application of Glycerol for Induced Powdery Mildew Resistance in Triticum aestivum L.

    Science.gov (United States)

    Li, Yinghui; Song, Na; Zhao, Chuanzhi; Li, Feng; Geng, Miaomiao; Wang, Yuhui; Liu, Wanhui; Xie, Chaojie; Sun, Qixin

    2016-01-01

    Previous work has demonstrated that glycerol-3-phosphate (G3P) and oleic acid (18:1) are two important signal molecules associated with plant resistance to fungi. In this article, we provide evidence that a 3% glycerol spray application 1-2 days before powdery mildew infection and subsequent applications once every 4 days was sufficient to stimulate the plant defense responses without causing any significant damage to wheat leaves. We found that G3P and oleic acid levels were markedly induced by powdery mildew infection. In addition, TaGLI1 (encoding a glycerol kinase) and TaSSI2 (encoding a stearoylacyl carrier protein fatty acid desaturase), two genes associated with the glycerol and fatty acid (FA) pathways, respectively, were induced by powdery mildew infection, and their promoter regions contain some fungal response elements. Moreover, exogenous application of glycerol increased the G3P level and decreased the level of oleic acid (18:1). Glycerol application induced the expression of pathogenesis-related ( PR ) genes ( TaPR-1, TaPR-2, TaPR-3, TaPR-4 , and TaPR-5 ), induced the generation of reactive oxygen species (ROS) before powdery mildew infection, and induced salicylic acid (SA) accumulation in wheat leaves. Further, we sprayed glycerol in a wheat field and found that it significantly ( p powdery mildew disease and lessened disease-associated kernel weight loss, all without causing any noticeable degradation in wheat seed quality.

  11. Glycerol positive promoters for tailored metabolic engineering of the yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Ho, Ping-Wei; Klein, Mathias; Futschik, Matthias; Nevoigt, Elke

    2018-05-01

    Glycerol offers several advantages as a substrate for biotechnological applications. An important step toward using the popular production host Saccharomyces cerevisiae for glycerol-based bioprocesses has been the fact that in recent studies commonly used S. cerevisiae strains were engineered to grow in synthetic medium containing glycerol as the sole carbon source. For metabolic engineering projects of S. cerevisiae growing on glycerol, characterized promoters are missing. In the current study, we used transcriptome analysis and a yECitrine-based fluorescence reporter assay to select and characterize 25 useful promoters. The promoters of the genes ALD4 and ADH2 showed 4.2-fold and 3-fold higher activities compared to the well-known strong TEF1 promoter. Moreover, the collection contains promoters with graded activities in synthetic glycerol medium and different degrees of glucose repression. To demonstrate the general applicability of the promoter collection, we successfully used a subset of the characterized promoters with graded activities in order to optimize growth on glycerol in an engineered derivative of CEN.PK, in which glycerol catabolism exclusively occurs via a non-native DHA pathway.

  12. Modifying the properties of whey protein isolate edible film by incorporating palm oil and glycerol

    Directory of Open Access Journals (Sweden)

    Vachiraya Liaotrakoon

    2018-02-01

    Full Text Available This study aimed to improve the properties of whey protein isolate (WPI films by incorporating palm oil (6, 7, and 8% w/w and glycerol (40, 50 and 60% w/w. The lightness of the films increased as glycerol levels increased, but the redness increased with the increased amount of oil content. Increasing the amounts of palm oil and glycerol improved flexibility (P<0.05, but reduced the strength of the film (P<0.05. Films with higher levels of palm oil and lower amounts of glycerol were less permeable to water vapor and oxygen, but more thermally stable. The size of particles and air bubbles in the films reduced with increased palm oil content, regardless of glycerol level. Among all formulae, the film prepared with 8% palm oil and 40% glycerol showed the best overall results. Modifying WPI films with palm oil and glycerol offers a simple technique for producing packaging with better environmental barrier properties.

  13. Trehalose in glycerol-free freezing extender enhances post-thaw survival of boar spermatozoa

    Science.gov (United States)

    ATHURUPANA, Rukmali; TAKAHASHI, Daisen; IOKI, Sumire; FUNAHASHI, Hiroaki

    2015-01-01

    Cryopreservation of boar semen is still considered suboptimal due to lower fertility as compared with fresh samples when glycerol, a permeating cryoprotectant, is used. Trehalose is a non-permeable cryoprotectant and nonreducing disaccharide known to stabilize proteins and biologic membranes. The aim of this study was to evaluate the cryosurvival and in vitro penetrability of boar spermatozoa when glycerol was replaced with trehalose in a freezing extender. Ejaculated Berkshire semen samples were diluted in egg yolk-based freezing extender containing glycerol (100 mM) or trehalose (0, 50, 100, 150, 200 and 250 mM) and cryopreserved using a straw freezing procedure. Thawed samples were analyzed for motility, viability, mitochondrial membrane potential (MMP), and acrosome integrity. In experiment 2, penetrability of spermatozoa cryopreserved with 100 mM glycerol or trehalose was examined. Replacement of cryoprotectant glycerol (100 mM) with trehalose had no effect on sperm viability, but replacing it with 100 mM trehalose improved motility, MMP and acrosome integrity significantly. Sperm motility and MMP were considerably higher in 100 mM trehalose, whereas the acrosome integrity was substantially higher in 100–250 mM trehalose. The in vitro penetration rate was also significantly higher in spermatozoa cryopreserved with trehalose (61.3%) than in those cryopreserved with glycerol (43.6%). In conclusion, 100 mM non-permeable trehalose can be used to replace glycerol, a permeating cryoprotectant, for maintenance of better post-thaw quality of boar spermatozoa. PMID:25754239

  14. Development of a Regional Glycerol Dialkyl Glycerol Tetraether (GDGT) - Temperature Calibration for Antarctic and sub-Antarctic Lakes

    Science.gov (United States)

    Roberts, S. J.; Foster, L. C.; Pearson, E. J.; Steve, J.; Hodgson, D.; Saunders, K. M.; Verleyen, E.

    2016-12-01

    Temperature calibration models based on the relative abundances of sedimentary glycerol dialkyl glycerol tetraethers (GDGTs) have been used to reconstruct past temperatures in both marine and terrestrial environments, but have not been widely applied in high latitude environments. This is mainly because the performance of GDGT-temperature calibrations at lower temperatures and GDGT provenance in many lacustrine settings remains uncertain. To address these issues, we examined surface sediments from 32 Antarctic, sub-Antarctic and Southern Chilean lakes. First, we quantified GDGT compositions present and then investigated modern-day environmental controls on GDGT composition. GDGTs were found in all 32 lakes studied. Branched GDGTs (brGDGTs) were dominant in 31 lakes and statistical analyses showed that their composition was strongly correlated with mean summer air temperature (MSAT) rather than pH, conductivity or water depth. Second, we developed the first regional brGDGT-temperature calibration for Antarctic and sub-Antarctic lakes based on four brGDGT compounds (GDGT-Ib, GDGT-II, GDGT-III and GDGT-IIIb). Of these, GDGT-IIIb proved particularly important in cold lacustrine environments. Our brGDGT-Antarctic temperature calibration dataset has an improved statistical performance at low temperatures compared to previous global calibrations (r2=0.83, RMSE=1.45°C, RMSEP-LOO=1.68°C, n=36 samples), highlighting the importance of basing palaeotemperature reconstructions on regional GDGT-temperature calibrations, especially if specific compounds lead to improved model performance. Finally, we applied the new Antarctic brGDGT-temperature calibration to two key lake records from the Antarctic Peninsula and South Georgia. In both, downcore temperature reconstructions show similarities to known Holocene warm periods, providing proof of concept for the new Antarctic calibration model.

  15. In situ crystallization and transformation kinetics of polymorphic forms of saturated-unsaturated-unsaturated triacylglycerols: 1-palmitoyl-2,3-dioleoyl glycerol, 1-stearoyl-2,3-dioleoyl glycerol, and 1-palmitoyl-2-oleoyl-3-linoleoyl glycerol.

    Science.gov (United States)

    Bayés-García, L; Calvet, T; Cuevas-Diarte, M A; Ueno, S

    2016-07-01

    We examined the influence of dynamic thermal treatment (variation of cooling/heating rates) on the polymorphic crystallization and transformation pathways of 1-palmitoyl-2,3-dioleoyl glycerol (POO), 1-stearoyl-2,3-dioleoyl glycerol (SOO), and 1-palmitoyl-2-oleoyl-3-linoleoyl glycerol (POL), which are major saturated-unsaturated-unsaturated (SUU) triacylglycerols (TAGs) of vegetable oils and animal fats (e.g., palm oil, olive oil, and Iberian ham fat). Using mainly a combination of differential scanning calorimetry (DSC) and synchrotron radiation X-ray diffraction (SR-XRD), we analyzed the polymorphic behavior of TAGs when high (15°Cmin -1 ), intermediate (2°Cmin -1 ), and low (0.5°Cmin -1 ) cooling and heating rates were applied. Multiple polymorphic forms were detected in POO, SOO, and POL (sub-α, α, β' 2 , and β' 1 ). Transient disordered phases, defined as kinetic liquid crystal (KLC) phases, were determined in POO and SOO for the first time. The results demonstrated that more stable forms were directly obtained from the melt by decreasing the cooling rates, whereas less stable forms predominated at high cooling rates, as confirmed in our previous work. Regarding heating rate variation, we confirmed that the nature of the polymorphic transformations observed (solid-state, transformation through KLC phase, or melt-mediation) depended largely on the heating rate. These results were discussed considering the activation energies involved in each process and compared with previous studies on TAGs with different saturated-unsaturated structures (1,3-dioleoyl-2-palmitoylglycerol, 1,3-dipalmitoyl-2-oleoyl-glycerol, trioleoyl glycerol, and 1,2-dioleoyl-3-linoleoyl glycerol). Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Reaction pathways for catalytic gas-phase oxidation of glycerol over mixed metal oxides

    Energy Technology Data Exchange (ETDEWEB)

    Suprun, W.; Glaeser, R.; Papp, H. [Leipzig Univ. (Germany). Inst. of Chemical Technology

    2011-07-01

    Glycerol as a main by-product from bio-diesel manufacture is a cheap raw material with large potential for chemical or biochemical transformations to value-added C3-chemicals. One possible way of glycerol utilization involves its catalytic oxidation to acrylic acid as an alternative to petrochemical routes. However, this catalytic conversion exhibits various problems such as harsh reaction conditions, severe catalyst coking and large amounts of undesired by-products. In this study, the reaction pathways for gas-phase conversion of glycerol over transition metal oxides (Mo, V und W) supported on TiO{sub 2} and SiO{sub 2} were investigated by two methods: (i) steady state experiments of glycerol oxidation and possible reactions intermediates, i.e., acrolein, 3-hydroxy propionaldehyde and acetaldehyde, and (ii) temperature-programmed surface reaction (TPSR) studies of glycerol conversion in the presence and in the absence of gas-phase oxygen. It is shown that the supported W-, V and Mo-oxides possess an ability to catalyze the oxidation of glycerol to acrylic acid. These investigations allowed us to gain a deeper insight into the reaction mechanism. Thus, based on the obtained results, three possible reactions pathways for the selective oxidation of glycerol to acrylic acid on the transition metal-containing catalysts are proposed. The major pathways in presence of molecular oxygen are a fast successive destructive oxidation of glycerol to CO{sub x} and the dehydration of glycerol to acrolein which is a rate-limiting step. (orig.)

  17. 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.

  18. Mechanical suitability of glycerol-preserved human dura mater for construction of prosthetic cardiac valves.

    Science.gov (United States)

    McGarvey, K A; Lee, J M; Boughner, D R

    1984-03-01

    We have examined the tensile viscoelastic properties of fresh and glycerol-preserved human dura mater, and correlated the results with structural information from the scanning electron microscope. The interwoven laminar structure of dura produces rather high flexural stiffness, while the crossed-fibrillar laminae produce planar mechanical isotropy. Glycerol storage shifts the stress-strain curve to lower strain, reduces stress relaxation and creep, and lowers the ultimate tensile strength and strain at fracture. These changes may be due to glyceraldehyde crosslinking, or to increased interfibrillar friction. The latter hypothesis suggests that glycerol storage may reduce the fatigue lifetime of the tissue.

  19. Acrolein Production by Gas-Phase Glycerol Dehydration Using PO₄/Nb₂O5 Catalysts.

    Science.gov (United States)

    Lee, Kyu Am; Ryoo, HeeKyoung; Ma, Byung Chol; Kim, Youngchul

    2018-02-01

    In this study, modified niobium oxide were prepared to study the addictive effects on the catalytic performance for gas-phase glycerol dehydration. The catalysts were characterized by N2 adsorption/desorption, XRD, NH3-TPD, FT-IR. The amount of phosphoric acid was up to 50 wt% in niobium. As a result, the highest glycerol conversion was achieved over 20 wt% PO4/Nb2O5. It indicates that the optimal amount of phosphoric acid leads the catalyst to have appropriate acidity which is an important factor for gas-phase glycerol dehydration.

  20. Synthesis and characterization of polyesters derived from glycerol and phthalic acid

    Directory of Open Access Journals (Sweden)

    Danilo Hansen Guimarães

    2007-09-01

    Full Text Available The production of polyester via polycondensation between glycerol and phthalic acid using dibutyltin dilaurate is reported. Three glycerol:phthalic acid molar ratio used for the bulk polymerization were: 2:2; 2:3 and 2:4. FTIR confirmed the esterification of glycerol by the acid for all the polymers. DSC indicated no crystallinity, although the XRD plots indicate a very incipient crystallinity for the polymers containing higher amounts of phthalic anhydride. Scanning electron microscopy results indicates high homogeneity for all the polymers prepared.

  1. Microbial Conversion of Waste Glycerol from Biodiesel Production into Value-Added Products

    Directory of Open Access Journals (Sweden)

    Hong Liu

    2013-09-01

    Full Text Available Biodiesel has gained a significant amount of attention over the past decade as an environmentally friendly fuel that is capable of being utilized by a conventional diesel engine. However, the biodiesel production process generates glycerol-containing waste streams which have become a disposal issue for biodiesel plants and generated a surplus of glycerol. A value-added opportunity is needed in order to compensate for disposal-associated costs. Microbial conversions from glycerol to valuable chemicals performed by various bacteria, yeast, fungi, and microalgae are discussed in this review paper, as well as the possibility of extending these conversions to microbial electrochemical technologies.

  2. A comparative evaluation of plasma glycerol and free fatty acids in patients with ischaemic heart disease

    Directory of Open Access Journals (Sweden)

    Singh V

    1979-01-01

    Full Text Available Plasma glycerol concentration was determined in 158 patients admitted to the hospital with acute chest pain. The patients were retrospectively divided into five groups according to their diagnosis, taking into account the presence or absence of myocardial infarc-tion and complicating arrythmias, The plasma glycerol concentra-tion was significantly higher in the group with complicating arrhythmias, irrespective of whether infarction was present or not. Therefore it is proposed that elevation of plasma glycerol may provide an important clue to determine those myocardial ischaemia cases who may develop cardiac arrythmias at a later stage.

  3. Preparation of polymer blends from glycerol, fumaric acid and of poly(ethylene terephthalate) (PET) recycled

    International Nuclear Information System (INIS)

    Medeiros, Marina A.O.; Guimaraes, Danilo H.; Brioude, Michel M.; Jose, Nadia M.; Prado, Luis A.S. de A.

    2011-01-01

    Polymer blends based on recycled poly(ethylene terephthalate) (PET) and poly(glycerol fumarate) polyesters were prepared in different PET concentrations. The PET powder was dispersed during the poly(glycerol fumarate) synthesis at 260 deg C. The resulting blends were characterized by X-ray diffraction. The thermal stability of the materials was evaluated by thermogravimetric analysis and differential scanning calorimetry. The morphology was studies by scanning electron microscopy. The blends were clearly immiscible. The possibility of (interfacial) compatibilization of the PET domains, caused by transesterification reactions between PET and glycerol were discussed. (author)

  4. The fate of 14C-glycerol in the rice stem borer, Chilo suppressalis Walker (Lepidoptera : Pyralidae)

    International Nuclear Information System (INIS)

    Tsumuki, Hisaaki; Kanehisa, Katsuo

    1981-01-01

    The interconversion between glycogen and glycerol was examined during diapausing and post-diapausing stages by injecting 14 C-glycerol. Radioactive glycerol injected was rapidly incorporated into glycogen in diapausing larvae at 25 0 C even during increase of glycerol, showing that the interconversion between glycogen and glycerol may easily occur on warmer days in winter. However, this interconversion proceeded in the direction of glycerol synthesis at such low temperature as 4 0 C. The isotope injected was incorporated into various tissues to varying degrees, especially it was found predominantly in fat body glycogen. The degradation rate of 14 C-glycerol in diapausing larvae was lower than in post-diapausing larvae. On the other hand, in non-diapausing larvae which were shown to contain no glycerol, 14 C-glycerol was rapidly degraded in comparison with hibernating larvae. A cause of no glycerol accumulation in non-diapausing larvae may be attributed to such high activity of glycerol degradation. (author)

  5. 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

  6. The role of genotype in protection against gamma-radiation of E. coli cells by glycerol

    International Nuclear Information System (INIS)

    Amirtaev, K.G.; Krasavin, E.A.; Kozubek, S.; Tokarova, B.; Nyamsambuu, A.

    1984-01-01

    The protective effect of glycerol and anoxia on the survival of γ-irradiated E.coli cells of wild type, recA - , polA - mutants has been investigated. The protection by glycerol increases from recA - mutant to wild type and polA - mutant with dose modifying factors (DMF) being 2.03+-0.12, 2.52+-0.25, and 2.80+-0.26. Analogically the protection by hypoxia is genetically determined, too. The value of oxygen effect increases from 1.77+-0.23 for recA - mutant to 3.38+-0.29 for wild type cells and 4.66+-0.41 for polA - -mutant. The oxygen independent component of glycerol protection is geltically independent (DMF=2). Possible mechanisms of genetic determination of the protection by glycerol and anoxia are discussed

  7. Ultrafine ferromagnetic iron oxide nanoparticles: Facile synthesis by low temperature decomposition of iron glycerolate

    Energy Technology Data Exchange (ETDEWEB)

    Bartůněk, Vilém, E-mail: vilem.bartunek@vscht.cz [Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technická 5, 166 28 Prague 6 (Czech Republic); Průcha, David [Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technická 5, 166 28 Prague 6 (Czech Republic); Švecová, Marie [Department of Analytical Chemistry, Faculty of Chemical Engineering, University of Chemistry and Technology, Technická 5, 166 28 Prague 6 (Czech Republic); Ulbrich, Pavel [Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology, Technická 3, 166 28 Prague 6 (Czech Republic); Huber, Štěpán; Sedmidubský, David; Jankovský, Ondřej [Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technická 5, 166 28 Prague 6 (Czech Republic)

    2016-09-01

    We synthesized dark colored ultrafine – sub 10 nm iron oxide nanoparticles by a facile and low temperature process based on thermal decomposition of an affordable precursor – iron glycerolate. Simultaneous thermal analysis (STA) was used to study the thermal behaviour during the decomposition. The iron glycerolate was thoroughly analysed by various methods. The size of the iron nanoparticles was determined from XRD patterns and by transmission electron microscopy (TEM) and their composition has been confirmed by XPS. Magnetic properties of the nanoparticles were studied by vibrating sample magnetometry. The prepared single phase material exhibiting ferromagnetic properties is usable in a wide range of applications and may be suitable even for large scale industrial applications. - Highlights: • Iron glycerolate prepared and characterised. • Iron oxide nanoparticles prepared by thermal decomposition of iron glycerolate. • STA used to study the decomposition. • Products characterised by XRD, XPS, FT-IR, SEM and TEM. • Magnetic behaviour of monophasic samples determined.

  8. Green silicone elastomer obtained from a counterintuitively stable mixture of glycerol and PDMS

    DEFF Research Database (Denmark)

    Mazurek, P.; Hvilsted, S.; Skov, A. L.

    2016-01-01

    A green and cheap silicone-based elastomer has been developed. Through the simple mixing-in of biodiesel-originating glycerol into commercially available polydimethylsiloxane (PDMS) pre-polymer, a glycerol-in-PDMS emulsion was produced. This counterintuitively stable mixture became a basis...... for obtaining elastomeric composites with uniformly distributed glycerol droplets. Various compositions, containing from 0 to 140 parts of glycerol per 100 parts of PDMS by weight, were prepared and investigated in terms of ATR-FTIR, broadband dielectric spectroscopy, mechanical properties as well as optical......, even in the presence of very high loadings. The conducted experiments highlight the great potential of this new type of elastomer and reveal some possible applications....

  9. 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

    . 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......Yarrowia lipolytica is an attractive host for sustainable bioprocesses due to its ability to utilize a variety of carbon substrates and convert them to a range of different product types (including lipids, organic acids and polyols) under specific conditions. Despite an increasing number...... 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...

  10. Synthesis and characterization of unsatured polyesters from the reaction of glycerol with fumaric acid

    International Nuclear Information System (INIS)

    Medeiros, Marina A.O.; Brioude, Michel M.; Agrela, Sara P.; Rosa, Leandro O.S.; Jose, Nadia M.; Prado, Luis A.S.A.

    2009-01-01

    The biodiesel production from vegetable oils has been encouraged by the Brazilian Federal Government, since biodiesel is a renewable fuel. The utilization of glycerol (by-product of biodiesel production) has gained importance, since it corresponds to 30 wt-% of the produced biodiesel. In this context, the present work aims at preparing and characterizing polymers based on glycerol, which could have an application. In this way, the production of biodiesel could be further stimulated. Unsaturated polyesters were preparing by esterification of glycerol with fumaric acid. The reaction mixture was heated up to 240 deg C. After the polymerization was complete, the material was cast onto Teflon molds. The materials were characterized by Infrared Spectroscopy, X-ray diffraction. The thermal stability was evaluated by thermogravimetric analysis and differential scanning calorimetry. The materials showed thermal stability comparable to alkyd thermoset derived from maleic anhydride and glycerol. (author)

  11. Thermal Processing of Low-Grade Glycerol to Alcohols for Biodiesel Fuel Production, Phase II

    Science.gov (United States)

    2010-01-01

    Conversion of crude glycerol to value added products can broaden its use and ultimately reduce the cost of biodiesel production. During the second year of the project, results from previous experiments were used to comprehensively investigate the the...

  12. Synthesis of high purity monoglycerides from crude glycerol and palm stearin

    Directory of Open Access Journals (Sweden)

    Pakamas Chetpattananondh

    2008-07-01

    Full Text Available The optimum conditions for the glycerolysis of palm stearin and crude glycerol derived from biodiesel process werefound to be a reaction temperature of 200oC with a molar ratio of crude glycerol to palm stearin of 2.5:1, and a reaction timeof 20 minutes. The yield and purity of monoglycerides obtained under these conditions was satisfactory as compared withthe glycerolysis of pure glycerol. To increase the purity of monoglycerides a two-step process, removal of residual glyceroland crystallization, was proposed instead of either vacuum or molecular distillation. Residual glycerol was removed byadding hydrochloric acid followed by washing with hot water. Optimum conditions for crystallization were achieved byusing isooctane as a solvent and a turbine impeller speed of 200 rpm at a crystallization temperature of 35oC. A purity notexceeding 99 percent of monoglycerides was obtained with monopalmitin as the major product.

  13. Kinetic analysis of dihydroxyacetone production from crude glycerol by immobilized cells of Gluconobacter oxydans MTCC 904.

    Science.gov (United States)

    Dikshit, Pritam Kumar; Moholkar, Vijayanand S

    2016-09-01

    The present study has investigated kinetic features of bioconversion of biodiesel-derived crude glycerol to dihydroxyacetone with immobilized Gluconobacter oxydans cells using modified Haldane substrate-inhibition model. The results have been compared against free cells and pure glycerol. Relative variations in the kinetic parameters KS, KI, Vmax, n and X reveal that immobilized G. oxydans cells (on PU foam substrate) with crude glycerol as substrate give higher order of inhibition (n) and lower maximum reaction velocities (Vmax). These results are essentially implications of substrate transport restrictions across immobilization matrix, which causes retention of substrate in the matrix and reduction in fractional available substrate (X) for the cells. This causes reduction in both KS (substrate concentration at Vmax/2) and KI (inhibition constant) as compared to free cells. For immobilized cells, substrate concentration (Smax) corresponding to Vmax is practically same for both pure and crude glycerol as substrate. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Glass polymorphism in glycerol-water mixtures: I. A computer simulation study.

    Science.gov (United States)

    Jahn, David A; Wong, Jessina; Bachler, Johannes; Loerting, Thomas; Giovambattista, Nicolas

    2016-04-28

    We perform out-of-equilibrium molecular dynamics (MD) simulations of water-glycerol mixtures in the glass state. Specifically, we study the transformations between low-density (LDA) and high-density amorphous (HDA) forms of these mixtures induced by compression/decompression at constant temperature. Our MD simulations reproduce qualitatively the density changes observed in experiments. Specifically, the LDA-HDA transformation becomes (i) smoother and (ii) the hysteresis in a compression/decompression cycle decreases as T and/or glycerol content increase. This is surprising given the fast compression/decompression rates (relative to experiments) accessible in MD simulations. We study mixtures with glycerol molar concentration χ(g) = 0-13% and find that, for the present mixture models and rates, the LDA-HDA transformation is detectable up to χ(g) ≈ 5%. As the concentration increases, the density of the starting glass (i.e., LDA at approximately χ(g) ≤ 5%) rapidly increases while, instead, the density of HDA remains practically constant. Accordingly, the LDA state and hence glass polymorphism become inaccessible for glassy mixtures with approximately χ(g) > 5%. We present an analysis of the molecular-level changes underlying the LDA-HDA transformation. As observed in pure glassy water, during the LDA-to-HDA transformation, water molecules within the mixture approach each other, moving from the second to the first hydration shell and filling the first interstitial shell of water molecules. Interestingly, similar changes also occur around glycerol OH groups. It follows that glycerol OH groups contribute to the density increase during the LDA-HDA transformation. An analysis of the hydrogen bond (HB)-network of the mixtures shows that the LDA-HDA transformation is accompanied by minor changes in the number of HBs of water and glycerol. Instead, large changes in glycerol and water coordination numbers occur. We also perform a detailed analysis of the effects that

  15. Functional relevance of water and glycerol channels in Saccharomyces cerevisiae.

    Science.gov (United States)

    Sabir, Farzana; Loureiro-Dias, Maria C; Soveral, Graça; Prista, Catarina

    2017-05-01

    Our understanding of the functional relevance of orthodox aquaporins and aquaglyceroporins in Saccharomyces cerevisiae is essentially based on phenotypic variations obtained by expression/overexpression/deletion of these major intrinsic proteins in selected strains. These water/glycerol channels are considered crucial during various life-cycle phases, such as sporulation and mating and in some life processes such as rapid freeze-thaw tolerance, osmoregulation and phenomena associated with cell surface. Despite their putative functional roles not only as channels but also as sensors, their underlying mechanisms and their regulation are still poorly understood. In the present review, we summarize and discuss the physiological relevance of S. cerevisiae aquaporins (Aqy1 and Aqy2) and aquaglyceroporins (Fps1 and Yfl054c). In particular, the fact that most S. cerevisiae laboratory strains harbor genes coding for non-functional aquaporins, while wild and industrial strains possess at least one functional aquaporin, suggests that aquaporin activity is required for cell survival under more harsh conditions. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Mutations and phenotype in isolated glycerol kinase deficiency

    Energy Technology Data Exchange (ETDEWEB)

    Walker, A.P.; Muscatelli, F.; Stafford, A.N.; Monaco, A.P. [Inst. of Molecular Medicine, Oxford (United Kingdom)] [and others

    1996-06-01

    We demonstrate that isolated glycerol kinase (GK) deficiency in three families results from mutation of the Xp21 GK gene. GK mutations were detected in four patients with widely differing phenotypes. Patient 1 had a splice-site mutation causing premature termination. His general health was good despite absent GK activity, indicating that isolated GK deficiency can be silent. Patient 2 had GK deficiency and a severe phenotype involving psychomotor retardation and growth delay, bone dysplasia, and seizures, similar to the severe phenotype of one of the first described cases of GK deficiency. His younger brother, patient 3, also had GK deficiency, but so far his development has been normal. GK exon 17 was deleted in both brothers, implicating additional factors in causation of the severe phenotype of patient 2. Patient 4 had both GK deficiency with mental retardation and a GK missense mutation (D440V). Possible explanations for the phenotypic variation of these four patients include ascertainment bias; metabolic or environmental stress as a precipitating factor in revealing GK-related changes, as has previously been described in juvenile GK deficiency; and interactions with functional polymorphisms in other genes that alter the effect of GK deficiency on normal development. 36 refs., 4 figs., 1 tab.

  17. Penggunaan H-Zeolit dan Tawas dalam Pemurnian Crude Glycerol dengan Proses Adsorpsi dan Koagulasi

    OpenAIRE

    Isalmi Aziz, M.T; Nur Hijjah Bayani Fadhilah; Hendrawati Hendrawati

    2017-01-01

    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...

  18. Penggunaan H-Zeolit Dan Tawas Dalam Pemurnian Crude Glycerol Dengan Proses Adsorpsi Dan Koagulasi

    OpenAIRE

    Aziz, M.T, Isalmi; Fadhilah, Nur Hijjah Bayani; Hendrawati, Hendrawati

    2017-01-01

    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...

  19. Effects of copper, organic mercury and a mixture of the two on glycerol lysis of erythrocytes.

    OpenAIRE

    宮地,芳之

    1987-01-01

    The effects of copper, organic mercury and a mixture of the two on glycerol lysis of erythrocytes were examined. Copper ion and organic mercury (EMP; ethylmercury phosphate, and PCMB; sodium p-chloromercuricbenzoate) inhibited glycerol lysis of erythrocytes. The inhibitory effects was dependent on the incubation period. An equimolor solution of copper ion and EMP showed between copper ion and EMP. Similar results were obtained with copper and PCMB.

  20. Continuous fed-batch vacuum fermentation system for glycerol from molasses by the sulfite process

    Energy Technology Data Exchange (ETDEWEB)

    Kalle, G.P.; Naik, S.C.

    1985-01-01

    A continuous fed-batch vacuum fermentation system has been described for the production of glycerol from cane molasses (and juice) by a conventional sulfite process. A glycerol concentration of 80 g/l was achieved with a productivity of 30 g/l/day at a dilution rate of 0.4/day which is twice that from a vacuum batch process (15 g/l/day) or four times that obtained without vacuum (8 g/l/day). 8 references.

  1. Platinum–Rhenium synergy on reducible oxide supports in aqueous-phase glycerol reforming

    NARCIS (Netherlands)

    Ciftci, A.; Eren, S.; Ligthart, D.A.J.M.; Hensen, E.J.M.

    2014-01-01

    A significant support effect was observed for the aqueous-phase reforming (APR) of glycerol over a series of Pt- and PtRe-loaded ceria-, ceria–zirconia-, zirconia-, and titania-supported catalysts. Glycerol conversion rates decreased in the order Pt/TiO2>Pt/ZrO2>Pt/CeZrO2>Pt/CeO2. Upon addition of

  2. Enhanced enzymatic activity of glycerol-3-phosphate dehydrogenase from the cryophilic Saccharomyces kudriavzevii.

    Science.gov (United States)

    Oliveira, Bruno M; Barrio, Eladio; Querol, Amparo; Pérez-Torrado, Roberto

    2014-01-01

    During the evolution of the different species classified within the Saccharomyces genus, each one has adapted to live in different environments. One of the most important parameters that have influenced the evolution of Saccharomyces species is the temperature. Here we have focused on the study of the ability of certain species as Saccharomyces kudriavzevii to grow at low temperatures, in contrast to Saccharomyces cerevisiae. We observed that S. kudriavzevii strains isolated from several regions are able to synthesize higher amounts of glycerol, a molecule that has been shown to accumulate in response to freeze and cold stress. To explain this observation at the molecular level we studied the expression of glycerol biosynthetic pathway genes and we observed a higher expression of GPD1 gene in S. kudriavzevii compared to S. cerevisiae in micro-vinification conditions. We observed higher enzymatic activity of Gpd1p in S. kudriavzevii in response to osmotic and cold stress. Also, we determined that S. kudriavzevii Gpd1p enzyme presents increased catalytic properties that will contribute to increase glycerol production. Finally, we evaluated the glycerol production with S. cerevisiae, S. kudriavzevii or a recombinant Gpd1p variant in the same background and observed that the S. kudriavzevii enzyme produced increased glycerol levels at 12 or 28°C. This suggests that glycerol is increased in S. kudriavzevii mainly due to increased V max of the Gpd1p enzyme. All these differences indicate that S. kudriavzevii has changed the metabolism to promote the branch of the glycolytic pathway involved in glycerol production to adapt to low temperature environments and maintain the NAD(+)/NADH ratio in alcoholic fermentations. This knowledge is industrially relevant due to the potential use, for example, of S. cerevisiae-S. kudriavzevii hybrids in the wine industry where glycerol content is an important quality parameter.

  3. Influence of palm oil and glycerol on properties of fish skin gelatin-based films.

    Science.gov (United States)

    Nilsuwan, Krisana; Benjakul, Soottawat; Prodpran, Thummanoon

    2016-06-01

    Properties of fish skin gelatin film incorporated with palm oil at 50 and 75 % (w/w) as affected by glycerol at 0-30 % (w/w) were investigated. Increases in water vapour permeability and elongation at break along with decrease in tensile strength were noticed when levels of glycerol were increased (p fish skin gelatin films without drastic alteration of mechanical properties.

  4. Aqueous-phase reforming of crude glycerol : effect of impurities on hydrogen production

    NARCIS (Netherlands)

    Boga, Dilek A.; Liu, Fang; Bruijnincx, Pieter C. A.; Weckhuysen, Bert M.

    2016-01-01

    The aqueous-phase reforming (APR) of a crude glycerol that originates from an industrial process and the effect of the individual components of crude glycerol on APR activity have been studied over 1 wt% Pt/Mg-Al) O, 1 wt% Pt/Al2O3, 5 wt% Pt/Al2O3 and 5 wt% Pt/C catalysts at 29 bar and 225 degrees

  5. Room temperature synthesis of glycerol carbonate catalyzed by spray dried sodium aluminate microspheres

    OpenAIRE

    Sreerangappa, Ramesh; Debecker, Damien P.; 13th European Congress on Catalysis – EuropaCat 2017

    2017-01-01

    Nanostructured NaAlO2 microspheres are produced by one-pot spray dried route, and are characterized by various physico-chemical methods. The obtained solids are composed of spherical aggregates of sodium aluminate with small crystallite size and strong surface basicity. This makes them highly active catalysts in the base-catalyzed synthesis of glycerol carbonate from glycerol and dimethyl carbonate. The catalyst does not leach and showed good reusability up to three cycles.

  6. Physical-chemical basis of the protection of slowly frozen human erythrocytes by glycerol

    Energy Technology Data Exchange (ETDEWEB)

    Rall, W.F.; Mazur, P.; Souzu, H.

    1978-07-01

    One theory of freezing damage suggests that slowly cooled cells are killed by being exposed to increasing concentrations of electrolytes as the suspending medium freezes. A corollary to this view is that protective additives such as glycerol protect cells by acting colligatively to reduce the electrolyte concentration at any subzero temperature. Recently published phase-diagram data for the ternary system glycerol-NaCl-water by M.L. Shepard et al. (Cryobiology, 13: 9-23, 1976), in combination with the data on human red cell survival vs. subzero temperature presented here and in the companion study of Souzu and Mazur (Biophys. J., 23: 89-100), permit a precise test of this theory. Appropriate liquidus phase-diagram information for the solutions used in the red cell freezing experiments was obtained by interpolation of liquidus data of Shepard and his co-workers. The results of phase-diagram analysis of red cell survival indicate that the correlation between the temperature that yields 50% hemolysis (LT/sub 50/) and the electrolyte concentration attained at that temperature in various concentrations of glycerol is poor. With increasing concentrations of glycerol, the cells were killed at progressively lower concentrations of NaCl. For example, the LT/sub 50/ for cells frozen in the absence of glycerol corresponds to a NaCl concentration of 12 weight percent (2.4 molal), while for cells frozen in 1.75 M glycerol in buffered saline the LT/sub 50/ corresponds to 3.0 weight percent NaCl (1.3 molal). The data, in combination with other findings, lead to two conclusions: (a) The protection from glycerol is due to its colligative ability to reduce the concentration of sodium chloride in the external medium, but (b) the protection is less than that expected from colligative effects; apparently glycerol itself can also be a source of damage, probably because it renders the red cells susceptible to osmotic shock during thawing.

  7. Wide distribution of autochthonous branched glycerol dialkyl glycerol tetraethers (bGDGTs) in U.S. Great Basin hot springs

    Science.gov (United States)

    Hedlund, Brian P.; Paraiso, Julienne J.; Williams, Amanda J.; Huang, Qiuyuan; Wei, Yuli; Dijkstra, Paul; Hungate, Bruce A.; Dong, Hailiang; Zhang, Chuanlun L.

    2013-01-01

    Branched glycerol dialkyl glycerol tetraethers (bGDGTs) are membrane-spanning lipids that likely stabilize membranes of some bacteria. Although bGDGTs have been reported previously in certain geothermal environments, it has been suggested that they may derive from surrounding soils since bGDGTs are known to be produced by soil bacteria. To test the hypothesis that bGDGTs can be produced by thermophiles in geothermal environments, we examined the distribution and abundance of bGDGTs, along with extensive geochemical data, in 40 sediment and mat samples collected from geothermal systems in the U.S. Great Basin (temperature: 31–95°C; pH: 6.8–10.7). bGDGTs were found in 38 out of 40 samples at concentrations up to 824 ng/g sample dry mass and comprised up to 99.5% of total GDGTs (branched plus isoprenoidal). The wide distribution of bGDGTs in hot springs, strong correlation between core and polar lipid abundances, distinctness of bGDGT profiles compared to nearby soils, and higher concentration of bGDGTs in hot springs compared to nearby soils provided evidence of in situ production, particularly for the minimally methylated bGDGTs I, Ib, and Ic. Polar bGDGTs were found almost exclusively in samples ≤70°C and the absolute abundance of polar bGDGTs correlated negatively with properties of chemically reduced, high temperature spring sources (temperature, H2S/HS−) and positively with properties of oxygenated, low temperature sites (O2, NO−3). Two-way cluster analysis and nonmetric multidimensional scaling based on relative abundance of polar bGDGTs supported these relationships and showed a negative relationship between the degree of methylation and temperature, suggesting a higher abundance for minimally methylated bGDGTs at high temperature. This study presents evidence of the widespread production of bGDGTs in mats and sediments of natural geothermal springs in the U.S. Great Basin, especially in oxygenated, low-temperature sites (≤70°C). PMID:23964271

  8. Wide distribution of autochthonous branched glycerol dialkyl glycerol tetraethers (bGDGTs in U.S. Great Basin hot springs

    Directory of Open Access Journals (Sweden)

    Brian P. Hedlund

    2013-08-01

    Full Text Available Branched glycerol dialkyl glycerol tetraethers (bGDGTs are membrane-spanning lipids that likely stabilize membranes of some bacteria. Although bGDGTs have been reported previously in certain geothermal environments, it has been suggested that they may derive from surrounding soils since bGDGTs are known to be produced by soil bacteria. To test the hypothesis that bGDGTs can be produced by thermophiles in geothermal environments, we examined the distribution and abundance of bGDGTs, along with extensive geochemical data, in 40 sediment and mat samples collected from geothermal systems in the U.S. Great Basin (temperature: 31-95°C; pH: 6.8-10.7. bGDGTs were found in 38 out of 40 samples at concentrations up to 824 ng/g sample dry mass and comprised up to 99.5% of total GDGTs (branched plus isoprenoidal. The wide distribution of bGDGTs in hot springs, strong correlation between core and polar lipid abundances, distinctness of bGDGT profiles compared to nearby soils, and higher concentration of bGDGTs in hot springs compared to nearby soils provided evidence of in situ production, particularly for the minimally methylated bGDGTs I, Ib, and Ic. Polar bGDGTs were found almost exclusively in samples ≤ 70°C and the absolute abundance of polar bGDGTs correlated negatively with properties of chemically reduced, high temperature spring sources (temperature, H2S/HS- and positively with properties of oxygenated, low temperature sites (O2, NO3-. Two-way cluster analysis and nonmetric multidimensional scaling based on relative abundance of polar bGDGTs supported these relationships and showed a negative relationship between the degree of methylation and temperature, suggesting a higher abundance for minimally methylated bGDGTs at high temperature. This study presents evidence of the widespread production of bGDGTs in mats and sediments of natural geothermal springs in the U.S. Great Basin, especially in oxygenated, low-temperature sites (≤ 70°C.

  9. Malic acid production by chemically induced Aspergillus niger MTCC 281 mutant from crude glycerol.

    Science.gov (United States)

    Iyyappan, J; Bharathiraja, B; Baskar, G; Jayamuthunagai, J; Barathkumar, S; Anna Shiny, R

    2018-03-01

    In the present investigation, crude glycerol derived from transesterification process was utilized to produce the commercially-valuable malic acid. A combined resistant on methanol and malic acid strain of Aspergillus niger MTCC 281 mutant was generated in solid medium containing methanol (1-5%) and malic acid (40-80 g/L) by the adaptation process for 22 weeks. The ability of induced Aspergillus niger MTCC 281 mutant to utilize crude glycerol and pure glycerol to produce malic acid was studied. The yield of malic acid was increased with 4.45 folds compared with that of parent strain from crude glycerol. The highest concentration of malic acid from crude glycerol by using beneficial mutant was found to be 77.38 ± 0.51 g/L after 192 h at 25 °C. This present study specified that crude glycerol by-product from biodiesel production could be used for producing high amount of malic acid without any pretreatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Integral process of obtaining glycerol as a by-product of biodiesel production from castor oil

    Directory of Open Access Journals (Sweden)

    Leonel Romero

    2012-12-01

    Full Text Available The biodiesel is obtained from about 10 years ago in Europe, and now that it has taken hold as fuel for diesel engines, it is expected a clear increase in the production of this class of fuels in a the near future. The biodiesel is derived from the transesterification reaction of castor oil with methanol, which is the main by-product the glycerol with an approximate content of 10%. Besides catalyst residuals, soaps, methanol traces, mono and diglycerides in small percentages are presented. This study proposes the separation, purification and characterization of the glycerol obtained from the transesterificación reaction of the castor oil, in order to be able to market it in the national or international market, so that it fulfills the standards of quality, which means getting a pure glycerol and the appropriate physico-chemical characteristics and techniques. The glycerin-methyl esters separation is carried out by decantation being obtained a percentage of around 70% glycerol. This percentage is subsequently increased through the purification process, using hydrochloric acid. Glycerol characterization was carried out by physicochemical and organoleptic tests. The purification process allowed us to obtain a glycerol with a percentage of purity close to 98%. It was also tested by comparison with theoretical data that remnants influenced in the physiochemical properties

  11. Pathway Construction in Corynebacterium glutamicum and Strain Engineering To Produce Rare Sugars from Glycerol.

    Science.gov (United States)

    Yang, Jiangang; Zhu, Yueming; Men, Yan; Sun, Shangshang; Zeng, Yan; Zhang, Ying; Sun, Yuanxia; Ma, Yanhe

    2016-12-21

    Rare sugars are valuable natural products widely used in pharmaceutical and food industries. In this study, we expected to synthesize rare ketoses from abundant glycerol using dihydroxyacetone phosphate (DHAP)-dependent aldolases. First, a new glycerol assimilation pathway was constructed to synthesize DHAP. The enzymes which convert glycerol to 3-hydroxypropionaldehyde and l-glyceraldehyde were selected, and their corresponding aldehyde synthesis pathways were constructed in vivo. Four aldol pathways based on different aldolases and phosphorylase were gathered. Next, three pathways were assembled and the resulting strains synthesized 5-deoxypsicose, 5-deoxysorbose, and 5-deoxyfructose from glucose and glycerol and produce l-fructose, l-tagatose, l-sorbose, and l-psicose with glycerol as the only carbon source. To achieve higher product titer and yield, the recombinant strains were further engineered and fermentation conditions were optimized. Fed-batch culture of engineered strains obtained 38.1 g/L 5-deoxypsicose with a yield of 0.91 ± 0.04 mol product per mol of glycerol and synthesized 20.8 g/L l-fructose, 10.3 g/L l-tagatose, 1.2 g/L l-sorbose, and 0.95 g/L l-psicose.

  12. Biodiesel biorefinery: opportunities and challenges for microbial production of fuels and chemicals from glycerol waste.

    Science.gov (United States)

    Almeida, João R M; Fávaro, Léia C L; Quirino, Betania F

    2012-07-18

    The considerable increase in biodiesel production worldwide in the last 5 years resulted in a stoichiometric increased coproduction of crude glycerol. As an excess of crude glycerol has been produced, its value on market was reduced and it is becoming a "waste-stream" instead of a valuable "coproduct". The development of biorefineries, i.e. production of chemicals and power integrated with conversion processes of biomass into biofuels, has been singled out as a way to achieve economically viable production chains, valorize residues and coproducts, and reduce industrial waste disposal. In this sense, several alternatives aimed at the use of crude glycerol to produce fuels and chemicals by microbial fermentation have been evaluated. This review summarizes different strategies employed to produce biofuels and chemicals (1,3-propanediol, 2,3-butanediol, ethanol, n-butanol, organic acids, polyols and others) by microbial fermentation of glycerol. Initially, the industrial use of each chemical is briefly presented; then we systematically summarize and discuss the different strategies to produce each chemical, including selection and genetic engineering of producers, and optimization of process conditions to improve yield and productivity. Finally, the impact of the developments obtained until now are placed in perspective and opportunities and challenges for using crude glycerol to the development of biodiesel-based biorefineries are considered. In conclusion, the microbial fermentation of glycerol represents a remarkable alternative to add value to the biodiesel production chain helping the development of biorefineries, which will allow this biofuel to be more competitive.

  13. 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.

  14. Effective Removal of Heavy Metal Ions Using Glycerol and Starch Xanthate

    Directory of Open Access Journals (Sweden)

    Aliyu Mohammed

    2017-09-01

    Full Text Available Glycerol and insoluble starch xanthates were synthesised and effectively used in the removal of Pb, Cd and Cu from aqueous solutions. The insoluble metal complex formed between the sulphur atoms in the xanthates and the heavy metals were easily separated. Lower dosage of glycerol xanthate was required in each case, with the optimum molar ratio (M2+/GX of 2. Moreover, the use of glycerol xanthate required no pH adjustments to give a 100 % heavy metal removal within the range of the detection limit. As for the ISX, there was a remarkable metal scavenging activity when the ISX contained high amount of Sulphur per molecule (10.12% S and when the pH was adjusted to 6. Butyl xanthate was also synthesised to make a good comparison with the glycerol and insoluble starch xanthate. The xanthates from these two sustainable materials (Starch and glycerol are proven to be more effective in metal scavenging activity. FTIR and CHNS elemental analyses were used to prove the evidence of xanthation, in addition, 13C NMR was used to characterise the glycerol xanthate.

  15. Lack of Aquaporin 3 in bovine erythrocyte membranes correlates with low glycerol permeation.

    Science.gov (United States)

    Campos, Elisa; Moura, Teresa F; Oliva, Abel; Leandro, Paula; Soveral, Graça

    2011-05-13

    In general, erythrocytes are highly permeable to water, urea and glycerol. However, expression of aquaporin isoforms in erythrocytes appears to be species characteristic. In the present study, human (hRBC) and bovine (bRBC) erythrocytes were chosen for comparative studies due to their significant difference in membrane glycerol permeability. Osmotic water permeability (P(f)) at 23°C was (2.89 ± 0.37) × 10(-2) and (5.12 ± 0.61) × 10(-2)cms(-1) for human and bovine cells, respectively, with similar activation energies for water transport. Glycerol permeability (P(gly)) for human ((1.37 ± 0.26) × 10(-5)cms(-1)) differed in three orders of magnitude from bovine erythrocytes ((5.82 ± 0.37) × 10(-8)cms(-1)) that also showed higher activation energy for glycerol transport. When compared to human, bovine erythrocytes showed a similar expression pattern of AQP1 glycosylated forms on immunoblot analysis, though in slight higher levels, which could be correlated with the 1.5-fold larger P(f) found. However, AQP3 expression was not detectable. Immunofluorescence analysis confirmed the absence of AQP3 expression in bovine erythrocyte membranes. In conclusion, lack of AQP3 in bovine erythrocytes points to the lipid pathway as responsible for glycerol permeation and explains the low glycerol permeability and high E(a) for transport observed in ruminants. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Swelling and tensile properties of starch glycerol system with various crosslinking agents

    Science.gov (United States)

    Mohamed, R.; Mohd, N.; Nurazzi, N.; Siti Aisyah, M. I.; Fauzi, F. Mohd

    2017-07-01

    Brittle properties of starch had been overcome by the modification process. In this work, sago starch is being modified with variable amount of plasticiser, namely glycerol at 20 and 40% and crosslinking agent had been added to the system. The film of the modification and characterizations of the starch glycerol system with various crosslinking systems were produced by casting method. The film properties of the starch glycerol system were then characterized by tensile strength (mechanical properties) and swelling (physical properties). The modification of the starch glycerol had improved that system by increasing the tensile strength, modulus however lowering its elongation. The increasing in percentage of the water absorption and also swelling are due to the intrinsic hydroxyl groups presence from the starch and glycerol itself that can attract more water to the system. Upon crosslinking, films casted with chemicals namely, glyoxal, malonic acid, borax, PEG were characterised. It was found that, all the film of sago starch crosslinked and undergoing easy film formation. From this modification, borax and malonic acid crosslinking agent had been determined as the best crosslinking agent to the starch glycerol system.

  17. Communication: Contrasting effects of glycerol and DMSO on lipid membrane surface hydration dynamics and forces

    Energy Technology Data Exchange (ETDEWEB)

    Schrader, Alex M. [Department of Chemical Engineering, University of California, Santa Barbara, California 93106 (United States); Cheng, Chi-Yuan [Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106 (United States); Israelachvili, Jacob N. [Department of Chemical Engineering, University of California, Santa Barbara, California 93106 (United States); Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106 (United States); Materials Department, University of California, Santa Barbara, California 93106 (United States); Han, Songi [Department of Chemical Engineering, University of California, Santa Barbara, California 93106 (United States); Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106 (United States)

    2016-07-28

    Glycerol and dimethyl sulfoxide (DMSO) are commonly used cryoprotectants in cellular systems, but due to the challenges of measuring the properties of surface-bound solvent, fundamental questions remain regarding the concentration, interactions, and conformation of these solutes at lipid membrane surfaces. We measured the surface water diffusivity at gel-phase dipalmitoylphosphatidylcholine (DPPC) bilayer surfaces in aqueous solutions containing ≤7.5 mol. % of DMSO or glycerol using Overhauser dynamic nuclear polarization. We found that glycerol similarly affects the diffusivity of water near the bilayer surface and that in the bulk solution (within 20%), while DMSO substantially increases the diffusivity of surface water relative to bulk water. We compare these measurements of water dynamics with those of equilibrium forces between DPPC bilayers in the same solvent mixtures. DMSO greatly decreases the range and magnitude of the repulsive forces between the bilayers, whereas glycerol increases it. We propose that the differences in hydrogen bonding capability of the two solutes leads DMSO to dehydrate the lipid head groups, while glycerol affects surface hydration only as much as it affects the bulk water properties. The results suggest that the mechanism of the two most common cryoprotectants must be fundamentally different: in the case of DMSO by decoupling the solvent from the lipid surface, and in the case of glycerol by altering the hydrogen bond structure and intermolecular cohesion of the global solvent, as manifested by increased solvent viscosity.

  18. Boar spermatozoa cryopreservation in low glycerol/trehalose enriched freezing media improves cellular integrity.

    Science.gov (United States)

    Gutiérrez-Pérez, Oscar; Juárez-Mosqueda, María de Lourdes; Carvajal, Salvador Uribe; Ortega, María Elena Trujillo

    2009-06-01

    The use of glycerol for boar semen cryopreservation results in low fertility, possibly due to toxicity. This has led to recommend the use of solutions with less than 4% glycerol. Trehalose is a disaccharide known to stabilize proteins and biologic membranes during processes such as cryopreservation. Thus, it was decided to evaluate the cryoprotective effect of glycerol/trehalose mixtures. Effects on motility (M), viability (Vb) and acrosomal integrity (nA) were evaluated. Sperm samples were frozen in three different extenders: G4 contained 4% glycerol; T1 contained 1% glycerol plus 250 mM trehalose and T0.5 was constituted by 0.5% glycerol plus 250 mM trehalose. All extenders yielded similar post-freezing/thawing motility rates. Viability was diminished in T0.5 as compared to the others. In regard to acrosome integrity, it was twice as high (Pextender. Thus, T1 twice as many spermatozoa were alive, motile and intact, than in either T0.5 or G4, i.e. during freeze/thawing the use of T1 resulted in twice as many fertile cells as when using the other extenders. During our study, we noted that there were wide individual variations both in sperm viability and in motility.

  19. Dimethylformamide is not better than glycerol for cryopreservation of boar semen.

    Science.gov (United States)

    Malo, C; Gil, L; Cano, R; Martínez, F; García, A; Jerez, R A

    2012-05-01

    To improve the boar sperm cryopreservation process, the influence of the sugar (lactose, trehalose) source and the cryoprotectant [glycerol, dimethylformamide (DMF)] on the success of freezing was investigated. Sperm samples were frozen in one of six extenders: lactose plus 3% glycerol (LG); lactose plus 1.5% glycerol and 1.5% DMF (LGD); lactose plus 3% DMF (LD); trehalose plus 3% glycerol (TG); trehalose plus 1.5% glycerol and 1.5% DMF (TGD); trehalose plus 3% DMF (TD). Effects on motility, viability, acrosome integrity and hypoosmotic test (HOST) were measured. The results showed that extender containing 3% glycerol retained the highest motility percentages. In regard to viability and acrosome integrity, all extenders yielded similar rates except for the decreasing values of TD. Endosmosis was diminished in TD and LD at 2 h (P = 0.0018), as compared with the others. The results of the study demonstrated that the use of DMF as a cryoprotectant adversely affected boar sperm quality after cryopreservation. © 2011 Blackwell Verlag GmbH.

  20. On the role of the activation procedure of supported hydrotalcites for base catalyzed reactions: Glycerol to glycerol carbonate and self-condensation of acetone

    NARCIS (Netherlands)

    Alvarez, M.G.; Frey, A.M.; Bitter, J.H.; Segarra, A.M.; Jong, de K.P.; Medina, F.

    2013-01-01

    Bulk and carbon nanofiber supported MgAl hydrotalcites have been investigated as solid base catalysts for the synthesis of glycerol carbonate and dicarbonate and for the self-condensation of acetone. The supported materials exhibited a 300 times higher activity compared to bulk activated

  1. Blood-retinal barrier glycerol permeability in diabetic macular edema and healthy eyes: estimations from macular volume changes after peroral glycerol

    DEFF Research Database (Denmark)

    Thornit, Dorte Nellemann; Vinten, Carl Martin; Sander, Birgit

    2010-01-01

    PURPOSE: To compare the changes in macular volume (MV) between healthy subjects and patients with diabetic macular edema (DME) after an osmotic load and to determine the glycerol permeability (P(gly)) of the blood-retinal barrier (BRB). METHODS: In this unmasked study, 13 patients with DME and 5...

  2. Use of glycerol-preserved corneas for corneal transplants

    Directory of Open Access Journals (Sweden)

    Neeti Gupta

    2017-01-01

    Full Text Available Purpose: This study was carried out to see the results of glycerol-preserved cornea (GPC in emergency situation when fresh corneal tissue was not available. The aim was to study the outcome of corneal transplantation using GPC. Methods: This was a retrospective study. The medical records of all the patients were reviewed, who underwent keratoplasty using “GPC” during the period from October 2011 to December 2015. The indication of keratoplasty, duration of preservation of the GPC, and its outcome were analyzed. Descriptive statistics were applied. Results: Out of the 222 penetrating keratoplasty (PKP performed over the study period, the GPC was used in 34 patients (males = 31, 91.2% aged 15–74 years. Therapeutic keratoplasty was performed in all cases in this cohort except one in which tectonic keratoplasty was done. The primary indication of PKP (91.2% was infectious keratitis. Of these, 20 (64.5% patients presented with perforated corneal ulcers. Post-PKP, ocular anatomy was preserved in 91.2%, and visual acuity of perception of light positive and accurate projection of rays in all the quadrants was obtained in 76.5% cases. Complications included glaucoma (n = 12, 35.1%, phthisis bulbi (n = 2, 5.9%, and graft reinfection and endophthalmitis after PKP (n = 1, 2.9%. The secondary procedure post-GPC and PKP were trabeculectomy with mitomycin C (n = 7, 58.3% in patients not controlled on topical antiglaucoma medication. Optical keratoplasty was performed in (n = 3 8.8% patients and triple procedure in (n = 2 5.8% patients with good visual acuity postprocedure. Conclusions: Acellular GPCs are useful in emergency keratoplasty to avoid loss of vision and can save the eye.

  3. Studies on distribution and excretion of 14C-glycerol in rats, rabbits and mice

    International Nuclear Information System (INIS)

    Takanashi, Shigeru; Kamiyama, Hiroshi; Suzuki, Hidetaka; Tohira, Yasuo; Ogawa, Machiko

    1978-01-01

    Tissue distribution and excretion of uniformly labeled 14 C-glycerol were investigated using rats, rabbits and mice. Blood disappearance half life of 14 W/V% 14 C-glycerol in mice (1 ml/head), rats (1 ml/head) and rabbits (2 ml/head) given intravenously was 0.4, 1.8 and 2.4 hours, respectively. When 14 W/V% 14 C-glycerol was injected in rats (1 ml/head) and rabbits (2 ml/head), 65% of administered radioactivity was excreted in to expired air within 48 hrs. This suggests that glycerol is mostly metabolised via the Embden-Meyehof pathway and the TCA cycle, and finally converted to CO 2 and H 2 O. At a low dose, the conversion ratio to CO 2 was greater than the case of a high dose, and a inverse relationship was observed between the CO 2 -conversion ratio and the dose. At levels above 1 ml of 56 W/V% glycerol, an approximately constant portion of the administered dose appeared to be oxidized. The results of the whole body autoradiogram showed the distribution of the radioactivity throughout the body. Disappearance of radioactivity from liver and blood was rapid, but transport to brain, excretion to the salivary gland, and secretion to Harder's gland were slow. The distribution in tissues showed that the highest distribution of 14 C-glycerol was found in the carcass; liver showed the next highest distribution; high distribution was also found initially in the kidneys; brain, heart, lung and spleen showed low distribution, but they decreased with time elapsed. Disappearance of radioactivity from the brain was relatively slower than the liver. Besides, another result indicated that in pregnant mice 14 C-glycerol did not cross the placenta very quickly. The fact that the apparent disappearance rate from the foetuses does not seem to parallel that of the placenta is suggestive of selective accumulation in foetal tissues. (auth.)

  4. Aquaglyceroporin-null trypanosomes display glycerol transport defects and respiratory-inhibitor sensitivity.

    Directory of Open Access Journals (Sweden)

    Laura Jeacock

    2017-03-01

    Full Text Available Aquaglyceroporins (AQPs transport water and glycerol and play important roles in drug-uptake in pathogenic trypanosomatids. For example, AQP2 in the human-infectious African trypanosome, Trypanosoma brucei gambiense, is responsible for melarsoprol and pentamidine-uptake, and melarsoprol treatment-failure has been found to be due to AQP2-defects in these parasites. To further probe the roles of these transporters, we assembled a T. b. brucei strain lacking all three AQP-genes. Triple-null aqp1-2-3 T. b. brucei displayed only a very moderate growth defect in vitro, established infections in mice and recovered effectively from hypotonic-shock. The aqp1-2-3 trypanosomes did, however, display glycerol uptake and efflux defects. They failed to accumulate glycerol or to utilise glycerol as a carbon-source and displayed increased sensitivity to salicylhydroxamic acid (SHAM, octyl gallate or propyl gallate; these inhibitors of trypanosome alternative oxidase (TAO can increase intracellular glycerol to toxic levels. Notably, disruption of AQP2 alone generated cells with glycerol transport defects. Consistent with these findings, AQP2-defective, melarsoprol-resistant clinical isolates were sensitive to the TAO inhibitors, SHAM, propyl gallate and ascofuranone, relative to melarsoprol-sensitive reference strains. We conclude that African trypanosome AQPs are dispensable for viability and osmoregulation but they make important contributions to drug-uptake, glycerol-transport and respiratory-inhibitor sensitivity. We also discuss how the AQP-dependent inverse sensitivity to melarsoprol and respiratory inhibitors described here might be exploited.

  5. Integrated multienzyme electrochemical biosensors for the determination of glycerol in wines.

    Science.gov (United States)

    Gamella, M; Campuzano, S; Reviejo, A J; Pingarrón, J M

    2008-02-25

    The construction and performance of integrated amperometric biosensors for the determination of glycerol are reported. Two different biosensor configurations have been evaluated: one based on the glycerol dehydrogenase/diaphorase (GDH/DP) bienzyme system, and another using glycerol kinase/glycerol-3-phosphate oxidase/peroxidase (GK/GPOx/HRP). Both enzyme systems were immobilized together with the mediator tetrathiafulvalene (TTF) on a 3-mercaptopropionic acid (MPA) self-assembled monolayer (SAM)-modified gold electrode by using a dialysis membrane. The electrochemical oxidation of TTF at +150mV (vs. Ag/AgCl), and the reduction of TTF(+) at 0mV were used for the monitoring of the enzyme reactions for the bienzyme and trienzyme configurations, respectively. Experimental variables concerning both the biosensors composition and the working conditions were optimized for each configuration. A good repeatability of the measurements with no need of cleaning or pretreatment of the biosensors was obtained in both cases. After 51 days of use, the GDH/DP biosensor still exhibited 87% of the original sensitivity, while the GK/GPOx/HRP biosensor yielded a 46% of the original response after 8 days. Calibration graphs for glycerol with linear ranges of 1.0x10(-6) to 2.0x10(-5) or 1.0x10(-6) to 1.0x10(-5)M glycerol and sensitivities of 1214+/-21 or 1460+/-34microAM(-1) were obtained with GDH/DP and GK/GPOx/HRP biosensors, respectively. The calculated detection limits were 4.0x10(-7) and 3.1x10(-7)M, respectively. The biosensors exhibited a great sensitivity with no significant interferences in the analysis of wines. The biosensors were applied to the determination of glycerol in 12 different wines and the results advantageously compared with those provided by a commercial enzyme kit.

  6. 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

    that popular wild-type laboratory yeast strains, commonly applied in metabolic engineering studies, did not grow or grew very slowly in glycerol medium.In this work, an adaptive laboratory evolution approach to obtain S. cerevisiae strains with an improved ability to grow on glycerol was applied. A broad array...... of evolved strains, which exhibited a significant increase in the specific growth rate and a higher glycerol consumption rate, were isolated. The best performing strains were further analyzed by classical genetics and whole genome re-sequencing in order to understand the molecular basis of glycerol...

  7. Anchor-dependent lipofection with non-glycerol based cytofectins containing single 2-hydroxyethyl head groups.

    Science.gov (United States)

    Venkata Srilakshmi, Gollapudi; Sen, Joyeeta; Chaudhuri, Arabinda; Ramadas, Yerramsetti; Madhusudhana Rao, Nalam

    2002-02-15

    Detailed structure-activity investigations aimed at probing the anchor chain length dependency for glycerol-based lipofectins have been reported previously. Herein, we report on the first detailed investigation on the anchor-dependent transfection biology of non-glycerol based simple monocationic cytofectins containing single 2-hydroxyethyl head group functionality using 11 new structural analogs of our previously published first generation of non-glycerol based transfection lipids (lipids 1-11). The C-14 and C-16 analogs of DOMHAC (lipids 4 and 5, respectively) were found to be remarkably efficient in transfecting COS-1 cells. In addition, the present anchor-dependency investigation also revealed that the C-14 analog of DOHEMAB (lipid 10) is significantly efficient in transfecting both COS-1 and NIH3T3 cells. Our results also indicate that too strong lipid-DNA interactions might result in weaker transfection for non-glycerol based cationic lipids. In summary, the anchor-dependence investigations presented here convincingly demonstrate that non-glycerol based cationic lipids containing a single hydroxyethyl head group and hydrophobic C-14 or C-16 anchors are promising non-toxic cationic transfection lipids for future use in liposomal gene delivery.

  8. Effect of Glycerol, as Cryoprotectant in the Encapsulation and Freeze Drying of Microspheres Containing Probiotic Cells

    Directory of Open Access Journals (Sweden)

    Oana Lelia Pop

    2015-05-01

    Full Text Available It is reported that probiotics provide several health benefits as they help in maintaining a good balance and composition of intestinal flora, and increase the resistance against invasion of pathogens. Ensuring adequate dosages of probiotics at the time of consumption is a challenge, because several factors during processing and storage affect the viability of probiotic organisms. Major emphasis has been given to protect the microorganisms with the help of encapsulation technique, by addition of different protectants. In this study, probiotic cells (Bifidobacterium lactis 300B were entrapped in alginate/pullulan microspheres. In the encapsulation formula glycerol was used as cryoprotectant in the freeze drying process for long time storage. It was observed that the survival of Bifidobacterium lactis 300B when encapsulated without cryoprotectant was higher than the formula with glycerol in the fresh obtained microspheres. The addition of glycerol was in order to reduce the deep freezing and freeze drying damages. In the chosen formulations, glycerol did not proved protection for the entrapped probiotic cells in the freeze drying process, for which the use of glycerol as cryoprotectant for alginate/pullulan Bifidobacterium lactis 300B entrapment is not recommended.

  9. Purification of crude glycerol from transesterification reaction of palm oil using direct method and multistep method

    Science.gov (United States)

    Nasir, N. F.; Mirus, M. F.; Ismail, M.

    2017-09-01

    Crude glycerol which produced from transesterification reaction has limited usage if it does not undergo purification process. It also contains excess methanol, catalyst and soap. Conventionally, purification method of the crude glycerol involves high cost and complex processes. This study aimed to determine the effects of using different purification methods which are direct method (comprises of ion exchange and methanol removal steps) and multistep method (comprises of neutralization, filtration, ion exchange and methanol removal steps). Two crude glycerol samples were investigated; the self-produced sample through the transesterification process of palm oil and the sample obtained from biodiesel plant. Samples were analysed using Fourier Transform Infrared Spectroscopy, Gas Chromatography and High Performance Liquid Chromatography. The results of this study for both samples after purification have showed that the pure glycerol was successfully produced and fatty acid salts were eliminated. Also, the results indicated the absence of methanol in both samples after purification process. In short, the combination of 4 purification steps has contributed to a higher quality of glycerol. Multistep purification method gave a better result compared to the direct method as neutralization and filtration steps helped in removing most excess salt, fatty acid and catalyst.

  10. Conversion of Crude Glycerol to 1, 3-Propanediol by Newly Isolated Kluyvera Cryocrescens

    International Nuclear Information System (INIS)

    Loh, S.K.; Stasha Eleanor Rosland Abel

    2016-01-01

    Bio diesel, an environmental-friendly and renewable fuel, has gained market share and popularity as an alternative to fossil fuel. While expanding its production globally to meet the demand, the production of its principal co-product, crude glycerol which is surplus and under utilised, has affected both the economic and environment. Crude glycerol has limited usage due to the impurities present. It cannot be disposed naturally in the environment and its storage and processing are very costly. Glycerol with its triglyceride backbone serves as a natural metabolite susceptible to microbial degradation into high value-added compounds. In this study, a novel 1,3-PD producing bacterial strain isolated from palm oil mill effluent was used in microbial fermentation of crude glycerol. The strain, identified as Kluyvera cryocrescens NBRC 102467 based on its 16S ribosomal ribonucleic acid sequences, was capable of producing 1,3-PD (5.28 g litre -1 ) along with by-products, butanol (0.34 g litre -1 ) and acetone (0.31 g litre -1 ) after an optimum 48 hour of incubation at 30 degree Celsius in agitated medium enriched with crude glycerol at 150 revolutions per minute. Interestingly, its productivity peaked at the 6 hour reaching 0.28 g litre -1 hour -1 and declined thereafter. In future, this strain has potential to be used in the bioprocess of interest. (author)

  11. Biotechnological conversion of glycerol from biofuels to 1,3-propanediol using Escherichia coli.

    Science.gov (United States)

    Przystałowska, Hanna; Lipiński, Daniel; Słomski, Ryszard

    2015-01-01

    In the face of shortage of fossil fuel supplies and climate warming triggered by excessive carbon dioxide emission, alternative resources for chemical industry have gained considerable attention. Renewable resources and their derivatives are of particular interest. Glycerol, which constitutes one of the by-products during biodiesel production, is such a substrate. Thus, generated excess glycerol may become an environmental problem, since it cannot be disposed of in the environment. The most promising products obtained from glycerol are polyols, including 1,3-propanediol, an important substrate in the production of synthetic materials, e.g. polyurethanes, unsaturated polyesters, and epoxy resins. Glycerol can be used as a carbon and energy source for microbial growth in industrial microbiology to produce 1,3-propanediol. This paper is a review of metabolic pathways of native producers and E. coli with the acquired ability to produce the diol via genetic manipulations. Culture conditions during 1,3-PDO production and genetic modifications of E. coli used in order to increase efficiency of glycerol bioconversion are also described in this paper.

  12. Conformational Preferences of Glycerol in the Gas Phase and in Water

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Keun Hong [Korea Military Academy, Seoul (Korea, Republic of); Byun, Byung Jin; Kang, Young Kee [Chungbuk National University, Cheongju (Korea, Republic of)

    2012-03-15

    The conformational study of glycerol has been carried out using the M06-2X/cc-pVTZ level of theory in the gas phase and the SMD M06-2X/cc-pVTZ level of theory in water in order to understand its conformational preferences and solvation effects. Most of the preferred conformers of glycerol have two C{sub 5} hydrogen bonds in the gas phase, as found by the analysis of calorimetric data. It has been known that the solvation drove the hydrogen bonds of glycerol to be weaker and its potential surface to be fatter and that glycerol exists as an ensemble of many feasible local minima in water. The calculated populations of glycerol in the gas phase and in water are consistent with the observed values, which are better than the previously calculated ones at the G2(MP2), CBS-QB3, and SM5.42 HF/6-31G(d) levels of theory

  13. Comparison of glycerol, lactamide, acetamide and dimethylsulfoxide as cryoprotectants of Japanese white rabbit spermatozoa.

    Science.gov (United States)

    Kashiwazaki, Naomi; Okuda, Yasushi; Seita, Yasunari; Hisamatsu, Shin; Sonoki, Shigenori; Shino, Masao; Masaoka, Toshio; Inomata, Tomo

    2006-08-01

    The rabbit is considered to be a valuable laboratory animal. We compared glycerol, lactamide, acetamide, and dimethylsulfoxide (DMSO) as cryoprotectants in egg-yolk diluent of ejaculated Japanese white rabbit spermatozoa for improvement of sperm cryopreservation methods. Rabbit semen was frozen with 1.0 M glycerol, lactamide, acetamide, or DMSO in plastic straws. Forward progressive motility and plasma membrane integrity of the post-thaw spermatozoa were examined. The rate of forward progressive motile spermatozoa in lactamide (37.8 +/- 3.0%) was significantly (P<0.05) higher than in glycerol (17.0 +/- 3.3%). In addition, the rates of sperm plasma membrane integrity in lactamide and acetamide (35.9 +/- 3.3% and 30.2 +/- 3.0%, respectively) were significantly (P<0.05) higher than in glycerol (17.0 +/- 2.6%). The results indicate that 1.0 M lactamide and acetamide have higher cryoprotective effects than 1.0 M glycerol for cryopreservation of Japanese white rabbit spermatozoa.

  14. Changes in rat respiratory system produced by exposure to exhaust gases of combustion of glycerol.

    Science.gov (United States)

    Serra, Daniel Silveira; Evangelista, Janaína Serra Azul Monteiro; Zin, Walter Araujo; Leal-Cardoso, José Henrique; Cavalcante, Francisco Sales Ávila

    2017-08-01

    The combustion of residual glycerol to generate heat in industrial processes has been suggested as a cost-effective solution for disposal of this environmental liability. Thus, we investigated the effects of exposure to the exhaust gases of glycerol combustion in the rat respiratory system. We used 2 rats groups, one exposed to the exhaust gases from glycerol combustion (Glycerol), and the other exposed to ambient air (Control). Exposure occurred 5h a day, 5days a week for 13 weeks. We observed statistically changes in all parameters of respiratory system mechanics in vivo. This results was supported by histological analysis and morphometric data, confirming narrower airways and lung parenchimal changes. Variables related to airway resistance (ΔR N ) and elastic properties of the tissue (ΔH), increased after challenge with methacholine. Finally, analysis of lung tissue micromechanics showed statistically increases in all parameters (R, E and hysteresivity). In conclusion, exhaust gases from glycerol combustion were harmful to the respiratory system. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Glycerol transesterification with ethyl acetate to synthesize acetins using ethyl acetate as reactant and entrainer

    Directory of Open Access Journals (Sweden)

    Amin Shafiei

    2017-03-01

    Full Text Available Transesterification of glycerol with ethyl acetate was performed over acidic catalysts in the batch and semi-batch systems. Ethyl acetate was used as reactant and entrainer to remove the produced ethanol during the reaction, through azeotrope formation. Since the azeotrope of ethyl acetate and ethanol forms at 70 oC, all the experiments were performed at this temperature. Para-toluene sulfonic acid, sulfuric acid, and Amberlyst 36 were used as catalyst. The effect of process parameters including ethyl acetate to glycerol molar ratio (6-12, reaction time (3-9 h, and the catalyst to glycerol weight (2.5-9.0%, on the conversion and products selectivities were investigated. Under reflux conditions, 100% glycerol conversion was obtained with 45%, 44%, and 11% selectivity to monoacetin, diacetin, and triacetin, respectively. Azeotropic reactive distillation led to 100% conversion of glycerol with selectivities of 3%, 48% and 49% for monoacetin, diacetin, and triacetin. During the azeotropic reactive distillation, it was possible to remove ethanol to shift the equilibrium towards diacetin and triacetin. Therefore, the total selectivity to diacetin and triacetin was increased from 55% to 97% through azeotropic distillation.

  16. Glycerol-plasticised silk membranes made using formic acid are ductile, transparent and degradation-resistant.

    Science.gov (United States)

    Allardyce, Benjamin J; Rajkhowa, Rangam; Dilley, Rodney J; Redmond, Sharon L; Atlas, Marcus D; Wang, Xungai

    2017-11-01

    Regenerated silk fibroin membranes tend to be brittle when dry. The use of plasticisers such as glycerol improve membrane ductility, but, when combined with aqueous processing, can lead to a higher degradation rate than solvent-annealed membranes. This study investigated the use of formic acid as the solvent with glycerol to make deformable yet degradation-resistant silk membranes. Here we show that membranes cast using formic acid had low light scattering, with a diffuse transmittance of less than 5% over the visible wavelengths, significantly lower than the 20% transmittance of aqueous derived silk/glycerol membranes. They had 64% β-sheet content and lost just 30% of the initial silk weight over 6h when tested with an accelerated enzymatic degradation assay, in comparison the aqueous membranes completely degraded within this timeframe. The addition of glycerol also improved the maximum elongation of formic acid derived membranes from under 3% to over 100%. They also showed good cytocompatibility and supported the adhesion and migration of human tympanic membrane keratinocytes. Formic acid based, silk/glycerol membranes may be of great use in medical applications such as repair of tympanic membrane perforation or ocular applications where transparency and resistance to enzymatic degradation are important. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Efficient production of succinic acid in immobilized fermentation with crude glycerol from Escherichia coli

    Directory of Open Access Journals (Sweden)

    Nik Nor Aziati, A.A.

    2017-10-01

    Full Text Available The increase in the price of commercial succinic acid has necessitated the need for its synthesis from waste materials such as glycerol. Glycerol residue is a waste product of Oleochemical production which is cheaply available and a very good source of carbon. The use of immobilized cells can further reduce the overall cost of the production process. This study primarily aims to produce succinic acid from glycerol residue through the use of immobilized Escherichia coli in a batch fermentation process. The parameters which affect bacterial fermentation process such as the mass substrate, temperature, inoculum size and duration of fermentation were screened using One-Factor-At-a-Time (OFAT method. The result of the screening process shows that a substrate (glycerol concentration of 30 g, inoculum size 20% v/v, and time 4 h produced the maximum succinic acid concentration of 117.99 g/L. The immobilized cells were found to be stable as well as retain their fermentative ability up to the 6th cycle of recycling, thereby presenting as an advantage over the free cell system. Therefore, conclude that using immobilized cells can contribute immensely to the cost-effective production of succinic acid from glycerol residue.

  18. Pharmacological investigations of Punica granatum in glycerol-induced acute renal failure in rats.

    Science.gov (United States)

    Singh, Amrit Pal; Singh, Amteshwar Jaggi; Singh, Nirmal

    2011-09-01

    The present study was designed to investigate the ameliorative potential and possible mechanism of hydroalcoholic extract of flowers of P. granatum in glycerol-induced acute renal failure (ARF) in rats. The rats were subjected to rhabdomyolytic ARF by single intramuscular injection of hypertonic glycerol (50% v/v; 8 ml/kg) and the animals were sacrificed after 24 hours of glycerol injection. The plasma creatinine, blood urea nitrogen, creatinine clearance, and histopathological studies were performed to assess the degree of renal injury. Pretreatment with hydroalcoholic extract of flowers of P. granatum (125 and 250 mg/kg p.o. twice daily for 3 days) significantly attenuated hypertonic glycerol-induced renal dysfunction in a dose-dependent manner. BADGE (Bisphenol-A-diglycidyl ether) (30 mg/kg), a peroxisome proliferator-activated receptor (PPAR)-γ antagonist, and N(omega)-nitro-l-arginine-methyl ester (L-NAME) (10, 20, and 40 mg/kg), nitric oxide synthase inhibitor, were employed to explore the mechanism of renoprotective effects of Punica granatum. Administration of BADGE (30 mg/kg) and L-NAME (40 mg/kg) abolished the beneficial effects of P. granatum in glycerol-induced renal dysfunction. Hydroalcoholic extract of flowers of P. granatum has ameliorative potential in attenuating myoglobinuric renal failure and its renoprotective effects involve activation of PPAR-γ and nitric oxide-dependent signaling pathway.

  19. Glycerol and urea can be used to increase skin permeability in reduced hydration conditions.

    Science.gov (United States)

    Björklund, Sebastian; Engblom, Johan; Thuresson, Krister; Sparr, Emma

    2013-12-18

    The natural moisturizing factor (NMF) is a group of hygroscopic molecules that is naturally present in skin and protects from severe drying. Glycerol and urea are two examples of NMF components that are also used in skin care applications. In the present study, we investigate the influence of glycerol and urea on the permeability of a model drug (metronidazole, Mz) across excised pig skin membranes at different hydrating conditions. The degree of skin hydration is regulated by the gradient in water activity across the membrane, which in turn depends on the water activity of the formulation in contact with the skin membrane. Here, we determine the water activity of all formulations employed using an isothermal calorimetric method. Thus, the gradient in water activity is controlled by a novel experimental set-up with well-defined boundary conditions on both sides of the skin membrane. The results demonstrate that glycerol and urea can retain high steady state flux of Mz across skin membranes at dehydrating conditions, which otherwise would decrease the permeability due to dehydration. X-ray diffraction measurements are performed to give insight into the effects of glycerol and urea on SC molecular organization. The novel steady state flux results can be related to the observation that water, glycerol, and urea all affect the structural features of the SC molecular components in a similar manner. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  20. Potential of glycerol and soybean oil for bioremediation of weathered oily-sludge contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, T.C.F.; Franca, F.P. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica], E-mail: fpfranca@eq.ufrj.br; Oliveira, F.J.S. [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil)

    2012-04-15

    The bioremediation of petroleum-contaminated soil was investigated on laboratory scale. This work evaluated the effect of co-substrate addition in tropical climate soil highly contaminated with oily residue. Glycerol and soybean oil were used as auxiliary co-substrates for contaminant degradation. Three different concentrations of co-substrate were tested, and the experiments were carried out over 60 days. The following parameters were monitored: humidity, pH, total heterotrophic bacteria, total fungi, total petroleum hydrocarbons (TPH), and the concentrations of benzo[a]pyrene and chrysene. The soil supplementation with renewable co-substrates improved the efficiency of the biodegradation TPH, with removals of 85% and 83% for glycerol and soybean oil, respectively, compared to a 55% removal yielded by the biodegradation process without supplementation. The use of glycerol increased Chrysene and Benzo[a]pyrene biodegradation by 50%, while soybean oil supplementation increased their removal by 36%. (author)

  1. Design and Control of Glycerol-tert-Butyl Alcohol Etherification Process

    Directory of Open Access Journals (Sweden)

    Elena Vlad

    2012-01-01

    Full Text Available Design, economics, and plantwide control of a glycerol-tert-butyl alcohol (TBA etherification plant are presented. The reaction takes place in liquid phase, in a plug flow reactor, using Amberlyst 15 as a catalyst. The products' separation is achieved by two distillation columns where high-purity ethers are obtained and a section involving extractive distillation with 1,4-butanediol as solvent, which separates TBA from the TBA/water azeotrope. Details of design performed in AspenPlus and an economic evaluation of the process are given. Three plantwide control structures are examined using a mass balance model of the plant. The preferred control structure fixes the fresh glycerol flow rate and the ratio glycerol + monoether : TBA at reactor-inlet. The stability and robustness in the operation are checked by rigorous dynamic simulation in AspenDynamics.

  2. High-pressure cloud point data for the system glycerol + olive oil + n-butane + AOT

    Directory of Open Access Journals (Sweden)

    J. P. Bender

    2008-09-01

    Full Text Available This work reports high-pressure cloud point data for the quaternary system glycerol + olive oil + n-butane + AOT surfactant. The static synthetic method, using a variable-volume view cell, was employed for obtaining the experimental data at pressures up to 27 MPa. The effects of glycerol/olive oil concentration and surfactant addition on the pressure transition values were evaluated in the temperature range from 303 K to 343 K. For the system investigated, vapor-liquid (VLE, liquid-liquid (LLE and vapor-liquid-liquid (VLLE equilibrium were recorded. It was experimentally observed that, at a given temperature and surfactant content, an increase in the concentration of glycerol/oil ratio led to a pronounced increase in the slope of the liquid-liquid coexistence curve. A comparison with results reported for the same system but using propane as solvent showed that much lower pressure transition values are obtained when using n-butane.

  3. Biodiesel Reactor Design with Glycerol Separation to Increase Biodiesel Production Yield

    Directory of Open Access Journals (Sweden)

    Budy Rahmat

    2013-09-01

    Full Text Available The study consisted of reactor design used for transesterification process, effect of glycerol separation ontransesterification reaction, determination of biodiesel quality, and mass balance analysis. The reactor was designed byintegrating circulated pump/stirrer, static mixer, and sprayer that intensify the reaction in the outer tank reactor. The objective was to reduce the use of methanol in excess and to shorten the processing time. The results showed that thereactor that applied the glycerol separation was able to compensate for the decreased use of the reactant methanol from 6:1 to 5:1 molar ratio, and changed the mass balance in the product, including: (i the increase of biodiesel productionfrom 42.37% to 49.34%, and (ii the reduction of methanol in excess from 42.37% to 32.89%. The results suggested that the efficiency of biodiesel production could be increased with the glycerol separation engineering.

  4. Effects of a physiological GH pulse on interstitial glycerol in abdominal and femoral adipose tissue

    DEFF Research Database (Denmark)

    Gravhølt, C H; Schmitz, Ole; Simonsen, L

    1999-01-01

    .0005). Administration of GH induced an increase in interstitial glycerol in both abdominal and femoral adipose tissue (ANOVA: abdominal, P = 0. 04; femoral, P = 0.03). There was no overall difference in the response to GH in the two regions during the study period as a whole (ANOVA: P = 0.5), but during peak...... stimulation of lipolysis abdominal adipose tissue was, in absolute but not in relative terms, stimulated more markedly than femoral adipose tissue (ANOVA: P = 0. 03 from 45 to 225 min). Peak interstitial glycerol values of 253 +/- 37 and 336 +/- 74 micromol/l were seen after 135 and 165 min in femoral...... and abdominal adipose tissue, respectively. ATBF was not statistically different in the two situations (ANOVA: P = 0.7). In conclusion, we have shown that a physiological pulse of GH increases interstitial glycerol concentrations in both femoral and abdominal adipose tissue, indicating activated lipolysis...

  5. Effect of pressure on the α relaxation in glycerol and xylitol

    Science.gov (United States)

    Paluch, M.; Casalini, R.; Hensel-Bielowka, S.; Roland, C. M.

    2002-06-01

    The effect of pressure on the dielectric relaxation of two polyhydroxy alcohols is examined by analysis of existing data on glycerol, together with new measurements on xylitol. The fragility, or Tg-normalized temperature dependence, changes with pressure for low pressures, but becomes invariant above 1 GPa. When compared at temperatures for which the α-relaxation times are equal, there is no effect of pressure (xylitol show an excess intensity at higher frequencies. For xylitol, unlike for glycerol, at lower temperatures this wing disjoins to form a separate peak. For both glass formers, elevated pressure causes the excess wing to become more separated from the peak maximum; that is, the properties of the primary and excess intensities are not correlated. This implies that the excess wing in glycerol is also a distinct secondary process, although it cannot be resolved from the primary peak.

  6. Supply Chain Optimization of Integrated Glycerol Biorefinery: GlyThink Model Development and Application

    DEFF Research Database (Denmark)

    Loureiro da Costa Lira Gargalo, Carina; Carvalho, Ana; Gernaey, Krist

    2017-01-01

    To further advance the development and implementation of glycerol-based biorefinery concepts, it is critical to analyze the glycerol conversion into high value-added products in a holistic manner, considering both production as well as the logistics aspects related to the supply chain structure...... is able to identify operational decisions, including locations, capacity levels, technologies, and product portfolio, as well as strategic decisions such as inventory levels, production amounts, and transportation to the final markets. Several technologies are considered for the glycerol valorization...... to high value-added products. Existing countries with major production and consumption of biodiesel in Europe are considered as candidates for the facility sites and demand markets, and their spatial distribution is also carefully studied. The results showed that (i) the optimal solution that provides...

  7. 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...

  8. Modelling of pyrolysis and combustion of gluten-glycerol-based bioplastics.

    Science.gov (United States)

    Gómez-Martínez, D; Barneto, A G; Martínez, I; Partal, P

    2011-05-01

    Non-isothermal thermogravimetric analysis, under nitrogen and air atmospheres, has been applied to study the thermal degradation of wheat gluten and gluten-glycerol-based bioplastics. In order to explain experimental data, thermal degradation has been simulated using the so-called pseudo-components, which are related to protein fraction (mainly gliadin and glutenin), residual starch and plasticiser. Thus, the proposed models have been used to shed some light on the thermal decomposition of these materials, which have been found affected by their compositions and microstructures. Modelling confirms the experimental bioplastic and gluten isolate compositions, e.g. bioplastic moisture content, starch concentration and the expected gliadin/glutenin ratio. According to the simulation, the glycerol volatilisation is affected by bioplastic moisture content and hindered by the protein matrix. A fact pointing out that glycerol/water blend plays relevant plasticizing roles in the protein matrix through diverse physicochemical interactions. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Differences in [14C]glycerol utilization in normal and familial hypercholesterolemic fibroblasts

    International Nuclear Information System (INIS)

    Shireman, R.B.; Durieux, J.

    1991-01-01

    It is known that cultured fibroblasts from familial hypercholesterolemia (FH) patients lack the normal cell receptor for low density lipoprotein (LDL) and that the absence of receptor-mediated transport of LDL cholesterol into these cells results in increased cellular synthesis of cholesterol. After 20 h perincubation in lipid-free medium, cultured FH fibroblasts incorporated significantly greater amounts of [ 14 C]glycerol into cellular lipids than did normal fibroblasts. Relative to the control medium which contained only bovine serum albumin (BSA), preincubation with 5% fetal bovine serum or 50 micrograms LDL/ml decreased [ 14 C]glycerol incorporation by both cell types. FH cells utilized more [ 14 C]glycerol for phospholipid synthesis and less for triglyceride synthesis than normal cells. This study indicates that LDL may be important in the transport of glycerides, as well as cholesterol, to cells

  10. Potential of Diverse Prokaryotic Organisms for Glycerol-based Polyhydroxyalkanoate Production

    Directory of Open Access Journals (Sweden)

    Martin Koller

    2015-06-01

    Full Text Available The potential and performance of various Gram-negative, Gram-positive and archaeal wild type microorganisms, and bacterial mixed cultures, as well as the application of genetically engineered strains as whole-cell biocatalysts for glycerol-based polyhydroxyalkanoate production are analyzed and assessed. This encompasses the comparison of growth and polyhydroxyalkanoate accumulation kinetics, thermo-mechanical properties of isolated glycerol-based polyhydroxyalkanoate of different composition on the monomeric level, and the presentation of mathematical models developed to describe glycerol-based polyhydroxyalkanoate production processes. For all these aspects, the article provides a detailed compilation of the contemporary state of knowledge, and gives an outlook to expected future developments.

  11. Comparison of chromatographic methods for the determination of bound glycerol in biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Foglia, T.A.; Jones, K.C.; Nunez, A.; Phillips, J.G. [U.S. Dept. of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, PA (United States); Mittelbach, M. [Inst. for Chemistry, Univ. of Graz, Graz (Austria)

    2004-09-01

    An important fuel criterion for biodiesel is bound glycerol, which is a function of the residual amount of triglycerides and partial glycerides in the biodiesel. Either high-temperature gas chromatography or high performance liquid chromatography can be used for determining these minor but important components in biodiesel. In this paper we have conducted a statistical study on the accuracy of the two methods for ascertaining the bound glycerol in biodiesel fuels obtained from different feedstocks. Analysis of variance showed that with one exception, namely diacylglycerols in some soy oil based biodiesel, there was no statistical difference in bound glycerol for the biodiesel samples analyzed or a difference between methods. Operationally, the high performance liquid chromatographic method is superior to the high temperature gas chromatographic method in that it requires no sample derivatization, has shorter analysis times, and is directly applicable to most biodiesel fuels. (orig.)

  12. 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...... to the identification of a conserved binding site for a putative regulator to be 5′-TGCGGGGA-3′, a binding site that is similar to the binding site for Adr1 in yeast and humans. We show that this Adr1 consensus binding sequence was over-represented on promoter regions of several genes in A. nidulans, A. oryzae and A...

  13. Crude Glycerol as Cost-Effective Fuel for Combined Heat and Power to Replace Fossil Fuels, Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, William L

    2012-10-31

    The primary objectives of this work can be summed into two major categories. Firstly, the fundamentals of the combustion of glycerol (in both a refined and unrefined form) were to be investigated, with emphasis of the development of a system capable of reliably and repeatedly combusting glycerol as well as an analysis of the emissions produced during glycerol combustion. Focus was placed on quantifying common emissions in comparison to more traditional fuels and this work showed that the burner developed was able to completely combust glycerol within a relatively wide range of operating conditions. Additionally, focus was placed on examining specific emissions in more detail, namely interesting NOx emissions observed in initial trials, acrolein and other volatile organic emissions, and particulate and ash emissions. This work showed that the combustion of crude glycerol could result in significantly reduced NOx emissions as a function of the high fuel bound oxygen content within the glycerol fuel. It also showed that when burned properly, the combustion of crude glycerol did not result in excessive emissions of acrolein or any other VOC compared to the combustion from more traditional fuels. Lastly however, this work has shown that in any practical application in which glycerol is being burned, it will be necessary to explore ash mitigation techniques due to the very high particulate matter concentrations produced during glycerol combustion. These emissions are comparable to unfiltered coal combustion and are directly tied to the biodiesel production method. The second focus of this work was directed to developing a commercialization strategy for the use of glycerol as a fuel replacement. This strategy has identified a 30 month plan for the scaling up of the laboratory scale burner into a pre-pilot scale system. Additionally, financing options were explored and an assessment was made of the economics of replacing a traditional fuel (namely natural gas) with crude

  14. Biohydrogen production by dark fermentation of glycerol using Enterobacter and Citrobacter Sp.

    Science.gov (United States)

    Maru, Biniam T; Constanti, Magda; Stchigel, Alberto M; Medina, Francesc; Sueiras, Jesus E

    2013-01-01

    Glycerol is an attractive substrate for biohydrogen production because, in theory, it can produce 3 mol of hydrogen per mol of glycerol. Moreover, glycerol is produced in substantial amounts as a byproduct of producing biodiesel, the demand for which has increased in recent years. Therefore, hydrogen production from glycerol was studied by dark fermentation using three strains of bacteria: namely, Enterobacter spH1, Enterobacter spH2, and Citrobacter freundii H3 and a mixture thereof (1:1:1). It was found that, when an initial concentration of 20 g/L of glycerol was used, all three strains and their mixture produced substantial amounts of hydrogen ranging from 2400 to 3500 mL/L, being highest for C. freundii H3 (3547 mL/L) and Enterobacter spH1 (3506 mL/L). The main nongaseous fermentation products were ethanol and acetate, albeit in different ratios. For Enterobacter spH1, Enterobacter spH2, C. freundii H3, and the mixture (1:1:1), the ethanol yields (in mol EtOH/mol glycerol consumed) were 0.96, 0.67, 0.31, and 0.66, respectively. Compared to the individual strains, the mixture (1:1:1) did not show a significantly higher hydrogen level, indicating that there was no synergistic effect. Enterobacter spH1 was selected for further investigation because of its higher yield of hydrogen and ethanol. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

  15. Ultraviolet stimulated melanogenesis by human melanocytes is augmented by di-acyl glycerol but not TPA

    International Nuclear Information System (INIS)

    Friedmann, P.S.; Wren, F.E.; Matthews, J.N.

    1990-01-01

    Epidermal melanocytes (MC) synthesize melanin in response to ultraviolet radiation (UVR). The mechanisms mediating the UV-induced activation of melanogenesis are unknown but since UVR induces turnover of membrane phospholipids generating prostaglandins (PGs) and other products, it is possible that one of these might provide the activating signal. We have examined the effects of prostaglandins (PGs) E1, E2, D2, F2 alpha, and di-acyl glycerol upon the UV-induced responses of cultured human MC and the Cloudman S91 melanoma cell line. The PGs had little effect on unirradiated cells and did not alter the response to UVR in either human MC or S91 melanoma cells. However, a synthetic analogue of di-acyl glycerol, 1-oleyl 2-acetyl glycerol (OAG), caused a significant (P less than 0.0001), dose-related augmentation of melanin content both in human MC (seven-fold) and S91 cells (three-fold). UVR caused a significant augmentation of the OAG-induced melanogenesis of both human MC and S91 cells. Since OAG is known to activate protein kinase C, it was possible that the observed modulation of the UVR signal could be via that pathway. Di-octanoyl glycerol, another di-acyl glycerol, which activates kinase C, caused a small (70%) increase in melanogenesis in MC which was not altered by UVR. However, 12-0 tetradecanoyl phorbol 13-acetate (TPA), a potent activator of protein kinase C, had no significant effect on either basal or UV-induced melanin synthesis in either cell type. These data suggest that the UV-induced signal activating melanogenesis could be mediated by di-acyl glycerol. Furthermore, they imply that the signal is transduced via an alternative, pathway that might be independent of protein kinase C

  16. Characterization of starch-based bioplastics from jackfruit seed plasticized with glycerol.

    Science.gov (United States)

    Santana, Renata Ferreira; Bonomo, Renata Cristina Ferreira; Gandolfi, Olga Reinert Ramos; Rodrigues, Luciano Brito; Santos, Leandro Soares; Dos Santos Pires, Ana Clarissa; de Oliveira, Cristiane Patrícia; da Costa Ilhéu Fontan, Rafael; Veloso, Cristiane Martins

    2018-01-01

    Biodegradable films based on starches from different botanical sources exhibited physicochemical and functional properties which were related with the starch characteristics. However, had inadequate mechanical properties and were hard and brittle. In this research, jackfruit seed starch plasticized with glycerol were developed and characterized. The starch and glycerol concentrations ranged from 2 to 6% w/w and 20 to 60 g/100 g starch, respectively. Bioplastics were obtained by the casting method and characterized in terms of color, mechanical properties, solubility, water vapor permeability ( WVP ), morphology and free energy of the hydrophobic interaction. Electronic micrographics showed the presence of some intact starch granules. The bioplastics were hydrophilic and those of 6% starch and 40% glycerol were the most hydrophilic ([Formula: see text] = 41.35 mJ m -1 ). The solubility of the films presented a direct relationship with the starch concentration ranging from 16.42 to 23.26%. Increased opacity and color difference were observed with increasing starch concentration. The WVP ranged from 1.374 × 10 -3 to 3.07 × 10 -4  g m/day m 2 which was positively related with the concentration of starch and glycerol. Tensile strength, percent elongation and Young's Modulus indicated that the jackfruit starch and glycerol provided a film with good mechanical properties. The results replaced that jackfruit starch can be used to develop films, with low opacity, moderate WVP and relatively high mechanical stability, by using glycerol in the gelatinized starch dispersions.

  17. 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.

  18. Biodiesel biorefinery: opportunities and challenges for microbial production of fuels and chemicals from glycerol waste

    Directory of Open Access Journals (Sweden)

    Almeida João R M

    2012-07-01

    Full Text Available Abstract The considerable increase in biodiesel production worldwide in the last 5 years resulted in a stoichiometric increased coproduction of crude glycerol. As an excess of crude glycerol has been produced, its value on market was reduced and it is becoming a “waste-stream” instead of a valuable “coproduct”. The development of biorefineries, i.e. production of chemicals and power integrated with conversion processes of biomass into biofuels, has been singled out as a way to achieve economically viable production chains, valorize residues and coproducts, and reduce industrial waste disposal. In this sense, several alternatives aimed at the use of crude glycerol to produce fuels and chemicals by microbial fermentation have been evaluated. This review summarizes different strategies employed to produce biofuels and chemicals (1,3-propanediol, 2,3-butanediol, ethanol, n-butanol, organic acids, polyols and others by microbial fermentation of glycerol. Initially, the industrial use of each chemical is briefly presented; then we systematically summarize and discuss the different strategies to produce each chemical, including selection and genetic engineering of producers, and optimization of process conditions to improve yield and productivity. Finally, the impact of the developments obtained until now are placed in perspective and opportunities and challenges for using crude glycerol to the development of biodiesel-based biorefineries are considered. In conclusion, the microbial fermentation of glycerol represents a remarkable alternative to add value to the biodiesel production chain helping the development of biorefineries, which will allow this biofuel to be more competitive.

  19. Partition and metabolic fate of dietary glycerol in muscles and liver of juvenile tilapia.

    Science.gov (United States)

    da Costa, Diego Vicente; Dias, Jorge; Colen, Rita; Rosa, Priscila Vieira; Engrola, Sofia

    2017-04-01

    This study investigated the effect of dietary glycerol on the metabolism of juvenile tilapia (Oreochromis mossambicus) and to determine its metabolic fate. The experimental diets contained 0% (Group CON), 5% (Group G5) and 15% glycerol (Group G15) and were fed for 40 d to apparent satiation, three times a day. For the metabolism trials, six fish from each treatment were randomly chosen and tube-fed with five pellets labelled with 14 C-glycerol [ 14 C(U)] in order to evaluate the absorption, catabolism, retention and partition of glycerol in muscle and liver. Group G5 presented the highest 14 C-glycerol retention and the lowest catabolism, with no significant differences between Groups CON and G15. In Group CON, the highest percentage of 14 C was incorporated in muscle lipids; with no significant differences between Groups G5 and G15. Furthermore, no treatment effects were found for hepatic 14 C-lipid and for 14 C in hepatic and muscle non-lipid extract. In the non-lipid and non-protein fraction, the highest radioactivity was measured in livers of Group G5, however no significant differences were found for this fraction between Groups CON and G15 in liver and for all treatments in muscle. The results of the present study can have practical implications in diet formulations for tilapia and for other aquaculture species with similar feeding pattern since juvenile tilapia are able to metabolise dietary glycerol into lipids, protein and/or carbohydrates and to use it as energy source.

  20. Temperature-Dependent Alkyl Glycerol Ether Lipid Composition of Mesophilic and Thermophilic Sulfate-Reducing Bacteria

    Directory of Open Access Journals (Sweden)

    Arnauld Vinçon-Laugier

    2017-08-01

    Full Text Available The occurrence of non-isoprenoid alkyl glycerol ether lipids in Bacteria and natural environments is increasingly being reported and the specificity and diagenetic stability of these lipids make them powerful biomarkers for biogeochemical and environmental studies. Yet the environmental controls on the biosynthesis of these peculiar membrane lipids remain poorly documented. Here, the lipid content of two mesophilic (Desulfatibacillum aliphaticivorans and Desulfatibacillum alkenivorans and one thermophilic (Thermodesulfobacterium commune sulfate-reducing bacteria—whose membranes are mostly composed of ether lipids—was investigated as a function of growth temperature (20–40°C and 54–84°C, respectively. For all strains, the cellular lipid content was lower at sub- or supra-optimal growth temperature, but the relative proportions of dialkyl glycerols, monoalkyl glycerols and fatty acids remained remarkably stable whatever the growth temperature. Rather than changing the proportions of the different lipid classes, the three strains responded to temperature changes by modifying the average structural composition of the alkyl and acyl chains constitutive of their membrane lipids. Major adaptive mechanisms concerned modifications of the level of branching and of the proportions of the different methyl branched lipids. Specifically, an increase in temperature induced mesophilic strains to produce less dimethyl branched dialkyl glycerols and 10-methyl branched lipids relative to linear structures, and the thermophilic strain to decrease the proportion of anteiso relative to iso methyl branched compounds. These modifications were in agreement with a regulation of the membrane fluidity. In one mesophilic and the thermophilic strains, a modification of the growth temperature further induced changes in the relative proportions of sn-2 vs sn-1 monoalkyl glycerols, suggesting an unprecedented mechanism of homeoviscous adaptation in Bacteria. Strong

  1. Glycerol Salicylate-based Pulp-Capping Material Containing Portland Cement.

    Science.gov (United States)

    Portella, Fernando Freitas; Collares, Fabrício Mezzomo; Santos, Paula Dapper; Sartori, Cláudia; Wegner, Everton; Leitune, Vicente Castelo Branco; Samuel, Susana Maria Werner

    2015-01-01

    The purpose of this study was to evaluate the water sorption, solubility, pH and ability to diffuse into dentin of a glycerol salicylate-based, pulp-capping cement in comparison to a conventional calcium hydroxide-based pulp capping material (Hydcal). An experimental cement was developed containing 60% glycerol salicylate resin, 10% methyl salicylate, 25% calcium hydroxide and 5% Portland cement. Water sorption and solubility were determined based on mass changes in the samples before and after the immersion in distilled water for 7 days. Material discs were stored in distilled water for 24 h, 7 days and 28 days, and a digital pHmeter was used to measure the pH of water. The cement's ability to diffuse into bovine dentin was assessed by Raman spectroscopy. The glycerol salicylate-based cement presented higher water sorption and lower solubility than Hydcal. The pH of water used to store the samples increased for both cements, reaching 12.59 ± 0.06 and 12.54 ± 0.05 after 7 days, for Hydcal and glycerol salicylate-based cements, respectively. Both cements were able to turn alkaline the medium at 24 h and sustain its alkalinity after 28 days. Hydcal exhibited an intense diffusion into dentin up to 40 µm deep, and the glycerol salicylate-based cement penetrated 20 µm. The experimental glycerol salicylate-based cement presents good sorption, solubility, ability to alkalize the surrounding tissues and diffusion into dentin to be used as pulp capping material.

  2. Effects of 2-deoxy-D-glucose, oligomycin and theophylline on in vitro glycerol metabolism in rat adipose tissue: response to insulin and epinephrine

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez, M C; Herrera, E [Barcelona Univ. (Spain). Catedra de Fisiologia General

    1976-01-01

    The effects of 2-deoxy-D-glucose (2DG), oligomycin and theophylline on the in vitro production and metabolism of glycerol and its response to insulin and epinephrine were studied in epididymal fat pads from fed rats. 2-DG failed to affect basic or epinephrine-stimulated glycerol production but decreased the uptake of 1-/sup 14/C-glycerol by the tissue and its conversion to glyceride-glycerol. Oligomycin also failed to affect the basic production of glycerol, but it inhibited the affect of epinephrine on this parameter as well as the uptake and utilization of 1-/sup 14/C-glycerol. Theophylline enhanced the production of glycerol by the tissue, and this effect was not further augmented by epinephrine. Theophylline also inhibited the uptake and utilization of 1-/sup 14/C-glycerol; the most pronounced effect of theophylline was observed in the formation of /sup 14/C-fatty acids from 1-/sup 14/C-glycerol in the presence of glucose. Insulin, but not epinephrine, decreased the inhibitory effect of theophylline on glycerol utilization. It is concluded that these compounds affect the ability of adipose tissue to metabolize glycerol more intensely than the ability to release it through lipolysis. The pathway for glycerol utilization in adipose tissue appears to be more sensitive to changes in the availability of ATP than the mechanisms for the release of glycerol from the tissue.

  3. 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...

  4. Thermal Reshaping of Gold Nanorods in Micellar Solution of Water/Glycerol Mixtures

    Directory of Open Access Journals (Sweden)

    Al Sayed A. Al-Sherbini

    2010-01-01

    Full Text Available Gold nanorods (Nds with aspect ratios of 4, 3.5, and 2.8 were prepared by the electrochemical method. The nanorods were thermally studied in binary solvents of aqueous glycerol at different ratios (25%–75%. The results illustrated that the longitudinal surface plasmon resonance (SPL is strongly dependent on the dielectric constant. The maximum absorption is red shifted with increasing the glycerol/water ratio. This was attributed to the decreasing value of the dielectric constant of the binary solvents. Moreover, by increasing the temperatures, the results showed relative instability of the gold nanorods. This attributed to the relative instability of the micelle capping the nanorods.

  5. High-pressure cloud point data for the system glycerol + olive oil + n-butane + AOT

    OpenAIRE

    Bender,J. P.; Junges,A.; Franceschi,E.; Corazza,F. C.; Dariva,C.; Oliveira,J. Vladimir; Corazza,M. L.

    2008-01-01

    This work reports high-pressure cloud point data for the quaternary system glycerol + olive oil + n-butane + AOT surfactant. The static synthetic method, using a variable-volume view cell, was employed for obtaining the experimental data at pressures up to 27 MPa. The effects of glycerol/olive oil concentration and surfactant addition on the pressure transition values were evaluated in the temperature range from 303 K to 343 K. For the system investigated, vapor-liquid (VLE), liquid-liquid (L...

  6. Formation and release of cellulolytic enzymes during growth of Trichoderma reesei on cellobiose and glycerol

    Energy Technology Data Exchange (ETDEWEB)

    Vaheri, M.P.; Vaheri, M.E.O.; Kaupinen, V.S.

    1979-01-01

    Production and release of cellulolytic enzymes by T. reesei QM 9414 were studied under induced and non-induced conditions and glycerol, respectively, as the only C source. There was a base level of cell debris-bound hydrolytic activity against filter paper and p-nitrophenyl glycoside even in T. reesei grown non-induced on glycerol. T. reesei grown on cellobiose was induced to produce large amounts of extracellular filter paper- and CMC-hydrolyzing enzymes, which were actively released even in the early stages of cultivation. Beta-Glucosidase was mainly detected in the cell debris and was not released unless the cells were autolyzing.

  7. A physicochemical study of sugar palm (Arenga Pinnata) starch films plasticized by glycerol and sorbitol

    Science.gov (United States)

    Poeloengasih, Crescentiana D.; Pranoto, Yudi; Hayati, Septi Nur; Hernawan, Rosyida, Vita T.; Prasetyo, Dwi J.; Jatmiko, Tri H.; Apriyana, Wuri; Suwanto, Andri

    2016-02-01

    The present work explores the physicochemical characteristics of sugar palm starch film for a potential hard capsule purpose. Sugar palm (Arenga pinnata) starch films were plasticized with glycerol or sorbitol in various concentrations (30% up to 50% w/w starch). Their effects on physicochemical properties of the films were investigated. The results showed that sugar palm starch was successfully developed as the main material of film using casting method. Incorporation of both glycerol or sorbitol affected the properties of films in different ways. It was found that thickness and solubility increased as plasticizer concentration increased, whereas retraction ratio, swelling degree and swelling thickness decreased with the increased plasticizer concentration.

  8. 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...... of variation were 2.0% and 9.7%, respectively. After derivatization, plasma samples were stable for at least 14 days. In conclusion, we have developed and validated a novel, accurate, and sensitive high-throughput liquid chromatography tandem mass spectrometry method for simultaneous determination of glucose...

  9. Room temperature synthesis of glycerol carbonate catalyzed by spray dried sodium aluminate microspheres

    OpenAIRE

    Sreerangappa, Ramesh; Debecker, Damien P.

    2017-01-01

    Nanostructured NaAlO2 microspheres are produced from an aqueous solution, by a one-pot spray drying route. The obtained solids are composed of spherical aggregates of sodium aluminate with small crystallite size and strong surface basicity. This makes them highly active catalysts in the base-catalyzed synthesis of glycerol carbonate from glycerol and dimethyl carbonate. The new catalyst does not leach and is recyclable. NaAlO2 microspheres outcompete commercially available NaAlO2 as well as o...

  10. Flow within an evaporating glycerol-water binary droplet: Segregation by gravitational effects

    Science.gov (United States)

    Li, Yaxing; Lv, Pengyu; Diddens, Christian; Wijshoff, Herman; Versluis, Michel; Lohse, Detlef

    2017-11-01

    The flow within an evaporating glycerol-water binary droplet with Bond number Bo PIV for both sessile and pendant droplets during evaporation process, which surprisingly show opposite radial flow directions - inward and outward, respectively. This observation clearly reveals that gravitational effects play a crucial role in controlling flow fields within the evaporating droplets. We theoretically analyse that this gravity-driven effect is caused by density gradients due to the local concentration difference of glycerol within the droplet triggered by different volatilities of the two components during evaporation. Finally, for confirmation, we numerically simulate the process, revealing a good agreement with experimental results.

  11. Study of the correlation between the temperature dependence of viscosity and excess quantities in glycerol

    International Nuclear Information System (INIS)

    Magazu, Salvatore; Migliardo, Federica

    2008-01-01

    The aim of the present paper is to investigate the behaviour of the kinematic viscosity, mean-square displacement and free volume of glycerol in order to theoretically and experimentally evaluate the fragility degree. Starting from the dependence of viscosity on temperature, the behaviour of the mean-square displacement and free volume of glycerol is analysed in order to point out the linear relationships between the logarithm of viscosity and the excess mean-square displacement and the excess free volume. As a conclusion, two fragility definitions, based on the observed links, are discussed

  12. Chemoselective Oxidation of Bio-Glycerol with Nano-Sized Metal Catalysts

    DEFF Research Database (Denmark)

    Li, Hu; Kotni, Ramakrishna; Zhang, Qiuyun

    2015-01-01

    to selectively oxidize glycerol and yield products with good selectivity is the use of nano-sized metal particles as heterogeneous catalysts. In this short review, recent developments in chemoselective oxidation of glycerol to specific products over nano-sized metal catalysts are described. Attention is drawn...... to various reaction parameters such as the type of the support, the size of the metal particles, and the acid/base properties of the reaction medium which were illustrated to largely influence the activity of the nanocatalyst and selectivity to the target product. - See more at: http...

  13. Application of glycerol as a foliar spray activates the defence response and enhances disease resistance of Theobroma cacao.

    Science.gov (United States)

    Zhang, Yufan; Smith, Philip; Maximova, Siela N; Guiltinan, Mark J

    2015-01-01

    Previous work has implicated glycerol-3-phosphate (G3P) as a mobile inducer of systemic immunity in plants. We tested the hypothesis that the exogenous application of glycerol as a foliar spray might enhance the disease resistance of Theobroma cacao through the modulation of endogenous G3P levels. We found that exogenous application of glycerol to cacao leaves over a period of 4 days increased the endogenous level of G3P and decreased the level of oleic acid (18:1). Reactive oxygen species (ROS) were produced (a marker of defence activation) and the expression of many pathogenesis-related genes was induced. Notably, the effects of glycerol application on G3P and 18:1 fatty acid content, and gene expression levels, in cacao leaves were dosage dependent. A 100 mm glycerol spray application was sufficient to stimulate the defence response without causing any observable damage, and resulted in a significantly decreased lesion formation by the cacao pathogen Phytophthora capsici; however, a 500 mm glycerol treatment led to chlorosis and cell death. The effects of glycerol treatment on the level of 18:1 and ROS were constrained to the locally treated leaves without affecting distal tissues. The mechanism of the glycerol-mediated defence response in cacao and its potential use as part of a sustainable farming system are discussed. © 2014 BSPP AND JOHN WILEY & SONS LTD.

  14. Glycerol-based deep eutectic solvents as extractants for the separation of MEK and ethanol via liquid-liquid extraction

    NARCIS (Netherlands)

    Rodriguez, N.R.; Ferré Güell, J.; Kroon, M.C.

    2016-01-01

    Four different glycerol-based deep eutectic solvents (DESs) were tested as extracting agents for the separation of the azeotropic mixture {methyl ethyl ketone + ethanol} via liquid-liquid extraction. The selected DESs for this work were: glycerol/choline chloride with molar ratios (4:1) and (2:1),

  15. Effect of fermentation parameters on bio-alcohols production from glycerol using immobilized Clostridium pasteurianum: an optimization study.

    Science.gov (United States)

    Khanna, Swati; Goyal, Arun; Moholkar, Vijayanand S

    2013-01-01

    This article addresses the issue of effect of fermentation parameters for conversion of glycerol (in both pure and crude form) into three value-added products, namely, ethanol, butanol, and 1,3-propanediol (1,3-PDO), by immobilized Clostridium pasteurianum and thereby addresses the statistical optimization of this process. The analysis of effect of different process parameters such as agitation rate, fermentation temperature, medium pH, and initial glycerol concentration indicated that medium pH was the most critical factor for total alcohols production in case of pure glycerol as fermentation substrate. On the other hand, initial glycerol concentration was the most significant factor for fermentation with crude glycerol. An interesting observation was that the optimized set of fermentation parameters was found to be independent of the type of glycerol (either pure or crude) used. At optimum conditions of agitation rate (200 rpm), initial glycerol concentration (25 g/L), fermentation temperature (30°C), and medium pH (7.0), the total alcohols production was almost equal in anaerobic shake flasks and 2-L bioreactor. This essentially means that at optimum process parameters, the scale of operation does not affect the output of the process. The immobilized cells could be reused for multiple cycles for both pure and crude glycerol fermentation.

  16. CHANGES OF GLYCEROL CONTENT IN DIAPAUSE LARVAEOF THE ORANGE WHEAT BLOSSOM MIDGE, SITODIPLOSIS MOSELLANA (GEHIN) IN VARIOUS SEASONS

    Institute of Scientific and Technical Information of China (English)

    Jun-xiangWu; FengYuan

    2004-01-01

    The glycerol contents in diapause larvae of the orange wheat blossom midge, Sitodiplosis mosellana (Gehin), collected from various seasons, were measured. The results showed that there was less glycerol content in larvae during living on the wheat head. Content of glycerol began to increase significantly when the larvae left the wheat head and entered the soil. A change trend of upper- lower- upper- lower in larvae glycerol contents during diapause in soil was observed from June to April of next year. More glycerol could be examined in larvae collected in summer and winter than in spring and autumn. There was not more glycerol in cocooned larvae than that in non-cocooned larvae during various seasons from the point of statistics. Comparing the glycerol content of larvae being diapause in the first year with that of larvae in the second year, there was yet no obvious difference when larvae were collected in the same season belonged to different years. Therefore, it is shown that the content of glycerol in larvae of the wheat midge in diapause is affected mainly by the seasons or diapause intensity.

  17. Synthesis of bio-additives: transesterification of ethyl acetate with glycerol using homogeneous or heterogeneous acid catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Meireles, Bruno A.; Pereira, Vera Lucia P., E-mail: patrocinio@nppn.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Centro de Ciencias da Saude. Nucleo de Pesquisas de Produtos Naturais

    2013-01-15

    A new catalytic route with potential practical interest to sustainable production of bioadditives from glycerol is described. Ethyl acetate was transesterified with glycerol, in the ratio glycerol:EtOAc 1:10, at 25 or 90 deg C using 0.1 equiv.of H{sub 2}SO{sub 4} or TsOH, as homogeneous catalysts. H{sub 2}SO{sub 4} led to the total glycerol consumption in 2 h. In the equilibrium, attained in 9 h, 100% yield of a diacetin:triacetin (55:45) mixture was formed. Using Amberlyst Registered-Sign 15 dry and Amberlyst Registered-Sign 16 wet in 1:30 glycerol:EtOAc ratio and reflux at 90 Degree-Sign C the total glycerol consumption was achieved in 2 and 10h, respectively. The lower reactivity of Amberlyst-16 wet was explained in terms of deactivation of acid sites and decrease in glycerol diffusion to the inner resin pores, both factors caused by adsorbed water. The kinetics of glycerol transformation and product distribution in the equilibrium in relation to the H{sub 2}SO{sub 4}, Amberlyst-15 (dry) and Amberlyst-16 (wet) catalyzed reactions were measured. (author)

  18. A new continuous-flow process for catalytic conversion of glycerol to oxygenated fuel additive: Catalyst screening

    International Nuclear Information System (INIS)

    Nanda, Malaya R.; Yuan, Zhongshun; Qin, Wensheng; Ghaziaskar, Hassan S.; Poirier, Marc-Andre; Xu, Chunbao

    2014-01-01

    Highlights: • A continuous-flow process for catalytic synthesis of solketal from glycerol. • Six different heterogeneous acid catalysts were studied in the process. • Glycerol conversion and solketal yield of 90% and 88% respectively were achieved. • The process has the potential to be scaled-up for industrial applications. - Abstract: A new continuous-flow reactor was designed for the conversion of glycerol to solketal, an oxygenated fuel additive, through ketalization with acetone. Six heterogeneous catalysts were investigated with respect to their catalytic activity and stability in a flow reactor. The acidity of the catalysts positively influences the catalyst’s activity. Among all the solid acid catalysts tested, the maximum solketal yield from experiments at 40 °C, 600 psi and WHSV of 4 h −1 attained 73% and 88% at the acetone/glycerol molar ratio of 2.0 and 6.0, respectively, with Amberlyst Wet. Based on the solketal yield and glycerol conversion results, the activity of all catalysts tested follows the following order of sequence: Amberlyst Wet ≈ Zeolite ≈ Amberlyst Dry > Zirconium Sulfate > Montmorillonite > Polymax. An increase in acetone/glycerol molar ratio or a decrease in WHSV enhanced the glycerol conversion as expected. This process offers an attractive route for converting glycerol, the main by-product of biodiesel, to solketal – a value-added green product with potential industrial applications as a valuable fuel additive or combustion promoter for gasoline engines

  19. Determination of steady state and nonsteady-state glycerol kinetics in humans using deuterium-labeled tracer

    International Nuclear Information System (INIS)

    Beylot, M.; Martin, C.; Beaufrere, B.; Riou, J.P.; Mornex, R.

    1987-01-01

    Using deuterium-labeled glycerol as tracer and gas-liquid chromatography-mass spectrometry techniques for the determination of isotopic enrichment, we have developed a simple and ethically acceptable method of determining glycerol appearance rate in humans under steady-state and nonsteady-state conditions. In normal subjects, the appearance rate of glycerol in the post-absorptive state was 2.22 +/- 0.20 mumol X kg-1 X min-1, a value in agreement with those reported in studies with radioactively labeled tracers. The ratio nonesterified fatty acid (NEFA) appearance rate/glycerol appearance rate ranged from 1.95 to 3.40. In insulin-dependent diabetic patients with a mild degree of metabolic control, the appearance rate of glycerol was 2.48 +/- 0.29 mumol X kg-1 X min-1. The volume of distribution of glycerol, determined by the bolus injection technique, was (mean) 0.306 l X kg-1 in normal subjects and 0.308 l X kg-1 in insulin-independent diabetic patients. To evaluate the usefulness of the method for determination of glycerol kinetics in nonsteady-state conditions, we infused six normal subjects with natural glycerol and calculated the isotopically determined glycerol appearance rate using a single compartment model (volume of distribution 0.31 l X kg-1). During these tests, the expected glycerol appearance rates were successively 5.03 +/- 0.33, 7.48 +/- 0.39, 9.94 +/- 0.34, 7.48 +/- 0.39, and 5.03 +/- 0.33 mumol +/- kg-1 X min-1, whereas the corresponding isotopically determined appearance rates were 4.62 +/- 0.45, 6.95 +/- 0.56, 10.85 +/- 0.51, 7.35 +/- 0.34, and 5.28 +/- 0.12 mumol X kg-1 X min-1

  20. Upgrading of glycerol from biodiesel synthesis with dimethyl carbonate on reusable Sr–Al mixed oxide catalysts

    International Nuclear Information System (INIS)

    Algoufi, Y.T.; Akpan, U.G.; Kabir, G.; Asif, M.; Hameed, B.H.

    2017-01-01

    Highlights: • Catalytic transesterification with dimethyl carbonate (DMC) converts glycerol into glycerol carbonate (GLC). • DMC and Sr_x–Al catalysts affect the reaction mechanisms that convert glycerol into GLC. • The morphology and textural structure of Sr_x–Al catalysts perpetuate catalytic activity. • The atomic ratio of Sr/Al has a unique effect on Sr–Al catalytic activity. • Sr_0_._5–Al catalyst exhibits limited leaching after five reaction cycles. - Abstract: The high demand for renewable energy has led to the upsurge of methanol-assisted biodiesel synthesis. Therefore, glycerol as a byproduct entered the waste stream given the oversupply of biodiesel to the market. The dimethyl carbonate (DMC)-assisted transesterification of glycerol on a catalyst has been a popular approach for converting glycerol into valuable glycerol carbonate (GLC). The synthesis of GLC from the DMC-assisted transesterification of glycerol on mixed oxide catalysts (Sr_x–Al) with different Sr/Al ratios was examined in this study. A glycerol conversion of 99.4% and a GLC yield of 100% were achieved in a catalyst with Sr/Al = 0.5 (Sr_0_._5–Al). Both values are higher than those in catalysts synthesized with Sr/Al = 0.25 and 0.75. The Sr_0_._5–Al catalyst withstood five transesterification reaction cycles without a serious deactivation induced by the leaching of active SrO. Therefore, the Sr_0_._5–Al catalyst is suitable for consecutive uses in the DMC-assisted transesterification of glycerol with DMC into GLC.

  1. Oxidation of Glycerol and Propanediols in Methanol over Heterogeneous Gold Catalysts

    DEFF Research Database (Denmark)

    Taarning, Esben; Madsen, Anders Theilgaard; Marchetti, Jorge

    2008-01-01

    Aerobic oxidation of glycerol over metal oxide supported gold nanoparticles in methanol results in the formation of dimethyl mesoxalate in selectivities up to 89% at full conversion. The oxidative esterification takes place in methanol, acting both as solvent and reactant, and in the presence of ...

  2. Glycerol production by Oenococcus oeni during sequential and simultaneous cultures with wine yeast strains.

    Science.gov (United States)

    Ale, Cesar E; Farías, Marta E; Strasser de Saad, Ana M; Pasteris, Sergio E

    2014-07-01

    Growth and fermentation patterns of Saccharomyces cerevisiae, Kloeckera apiculata, and Oenococcus oeni strains cultured in grape juice medium were studied. In pure, sequential and simultaneous cultures, the strains reached the stationary growth phase between 2 and 3 days. Pure and mixed K. apiculata and S. cerevisiae cultures used mainly glucose, producing ethanol, organic acids, and 4.0 and 0.1 mM glycerol, respectively. In sequential cultures, O. oeni achieved about 1 log unit at 3 days using mainly fructose and L-malic acid. Highest sugars consumption was detected in K. apiculata supernatants, lactic acid being the major end-product. 8.0 mM glycerol was found in 6-day culture supernatants. In simultaneous cultures, total sugars and L-malic acid were used at 3 days and 98% of ethanol and glycerol were detected. This study represents the first report of the population dynamics and metabolic behavior of yeasts and O. oeni in sequential and simultaneous cultures and contributes to the selection of indigenous strains to design starter cultures for winemaking, also considering the inclusion of K. apiculata. The sequential inoculation of yeasts and O. oeni would enhance glycerol production, which confers desirable organoleptic characteristics to wines, while organic acids levels would not affect their sensory profile. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Simultaneous production of hydrogen and ethanol from waste glycerol by Enterobacter aerogenes KKU-S1

    DEFF Research Database (Denmark)

    Reungsang, Alissara; Sittijunda, Sureewan; Angelidaki, Irini

    2013-01-01

    Factors affecting simultaneous hydrogen and ethanol production from waste glycerol by a newly isolated bacterium Enterobacter aerogenes KKU-S1 were investigated employing response surface methodology (RSM) with central composite design (CCD). The Plackett-Burman design was first used to screen...

  4. Production of Transglutaminase by Streptoverticillium ladakanum NRRL-3191 Using Glycerol as Carbon Source

    Directory of Open Access Journals (Sweden)

    Simón J. Téllez-Luis

    2004-01-01

    Full Text Available The enzyme transglutaminase (TG catalyses the formation of covalent bonds between adjacent proteins, thereby improving the gel structure of proteins and has important applications for the food industry. The aims of this work were: (i to elucidate the effect of agitation speed during the biotechnological production of TG by Streptoverticillium ladakanum NRRL-3191 using glycerol as carbon source; and (ii to improve TG production by optimising the composition of media based on glycerol, xylose and casein. An agitation speed of 250 rpm and a fermentation time of 72 h resulted in the optimal enzymatic activity (0.628 U/mL with a productivity of 0.087 U/(mL·h. The composition of media with glycerol, xylose and casein were optimised using an experimental design to improve TG production. The model predicts that the maximum TG activity (0.725 U/mL can be obtained using glycerol 50.5 g/L and casein 20 g/L without the addition of xylose.

  5. Superlubricity mechanism of diamond-like carbon with glycerol. Coupling of experimental and simulation studies

    International Nuclear Information System (INIS)

    Bouchet, M I De Barros; Matta, C; Le-Mogne, Th; Martin, J Michel; Zhang, Q; III, W Goddard; Kano, M; Mabuchi, Y; Ye, J

    2007-01-01

    We report a unique tribological system that produces superlubricity under boundary lubrication conditions with extremely little wear. This system is a thin coating of hydrogen-free amorphous Diamond-Like-Carbon (denoted as ta-C) at 353 K in a ta-C/ta-C friction pair lubricated with pure glycerol. To understand the mechanism of friction vanishing we performed ToF-SIMS experiments using deuterated glycerol and 13 C glycerol. This was complemented by first-principles-based computer simulations using the ReaxFF reactive force field to create an atomistic model of ta-C. These simulations show that DLC with the experimental density of 3.24 g/cc leads to an atomistic structure consisting of a 3D percolating network of tetrahedral (sp 3 ) carbons accounting for 71.5% of the total, in excellent agreement with the 70% deduced from our Auger spectroscopy and XANES experiments. The simulations show that the remaining carbons (with sp 2 and sp 1 character) attach in short chains of length 1 to 7. In sliding simulations including glycerol molecules, the surface atoms react readily to form a very smooth carbon surface containing OH-terminated groups. This agrees with our SIMS experiments. The simulations find that the OH atoms are mostly bound to surface sp 1 atoms leading to very flexible elastic response to sliding. Both simulations and experiments suggest that the origin of the superlubricity arises from the formation of this OH-terminated surface

  6. Geochemical and microbial community determinants of reductive dechlorination at a site biostimulated with glycerol

    NARCIS (Netherlands)

    Atashgahi, Siavash; Lu, Yue; Zheng, Ying; Saccenti, Edoardo; Suarez-Diez, Maria; Ramiro-Garcia, Javier; Eisenmann, Heinrich; Elsner, Martin; J.M. Stams, Alfons; Springael, Dirk; Dejonghe, Winnie; Smidt, Hauke

    2017-01-01

    Biostimulation is widely used to enhance reductive dechlorination of chlorinated ethenes in contaminated aquifers. However, the knowledge on corresponding biogeochemical responses is limited. In this study, glycerol was injected in an aquifer contaminated with cis-dichloroethene (cDCE), and

  7. Glycerol valorization: dehydration to acrolein over silica-supported niobia catalysts

    NARCIS (Netherlands)

    Shiju, N.R.; Brown, D.R.; Wilson, K.; Rothenberg, G.

    2010-01-01

    The catalytic dehydration of glycerol to acrolein is investigated over silica-supported niobia catalysts in a continuous fixed-bed gas-phase reactor. Various supported niobia catalysts are prepared and characterized using surface analysis and spectroscopic methods (XRD, UV-Vis, XPS, N2 adsorption),

  8. Synthesis of Acrolein from Glycerol Using FePO4 Catalyst in Liquid Phase Dehydration

    Directory of Open Access Journals (Sweden)

    Akhmad Zainal Abidin

    2016-02-01

    Full Text Available 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. The catalyst was prepared by three different methods: hydrothermal (catalyst A, deposition at Fe/P = 1.15 (catalyst B, and deposition at Fe/P = 1.20 (catalyst C. The experimental reaction temperature was varied at 220, 240 and 260 °C under constant atmospheric pressure. The results showed that catalyst C provided the best yield (91%, followed by catalyst A (90% and catalyst B (82%. The increasing reaction temperature showed a tendency to increase the yield of acrolein, while the presence of oxygen reduced the yield of acrolein and allowed the reaction to produce more side products such as glycerol propanal, acetaldehyde, and propionate. Catalyst reuse without any regeneration resulted in a yield profile of acrolein that continued to decline.

  9. Improvement in solvent tolerance by exogenous glycerol in Pseudomonas sp. BCNU 106.

    Science.gov (United States)

    Choi, H J; Lim, B R; Park, Y J; Joo, W H

    2017-08-01

    Solvent hypertolerant Pseudomonas sp. BCNU 106 still has some underlying growth limitation in solvents. Therefore, efficient mass cultivation methods are needed to pursue its applications in biotechnology. Pseudomonas sp. BCNU 106 was cultured in a medium supplemented with 0·05 mol l -1 glycerol and cell survival was monitored during its cultivation in the presence of 1% (v/v) toluene. Exogenously supplemented glycerol provided more protection against damage caused by toluene stress and conferred higher solvent tolerance of Pseudomonas sp. BCNU 106 to toluene compared to control Pseudomonas sp. BCNU 106 without the supplementation of glycerol. This low-cost mass cultivation method can be used to efficiently apply solvent-tolerant bacteria in biotransformation and biodegradation. Protection against toluene and improvement in bacterial cell growth by supplementation of glycerol in the presence of toluene are demonstrated in this study. This result can be used to solve growth-related hindrances of solvent-tolerant bacteria and establish their low-cost mass cultivation, thereby broadening their industrial and environmental applications. © 2017 The Society for Applied Microbiology.

  10. Non-Oberbeck-Boussinesq effects in two-dimensional Rayleigh-Bénard convection in glycerol

    NARCIS (Netherlands)

    Sugiyama, K.; Calzavarini, E.; Grossmann, S.; Lohse, Detlef

    2007-01-01

    We numerically analyze Non-Oberbeck-Boussinesq (NOB) effects in two-dimensional Rayleigh-Benard flow in glycerol, which shows a dramatic change in the viscosity with temperature. The results are presented both as functions of the Rayleigh number Ra up to 108 (for fixed temperature difference �

  11. Enhanced cellulase production by Trichoderma harzianum by cultivation on glycerol followed by induction on cellulosic substrates.

    Science.gov (United States)

    Delabona, Priscila da Silva; Lima, Deise Juliana; Robl, Diogo; Rabelo, Sarita Cândida; Farinas, Cristiane Sanchez; Pradella, José Geraldo da Cruz

    2016-05-01

    The use of glycerol obtained as an intermediate of the biodiesel manufacturing process as carbon source for microbial growth is a potential alternative strategy for the production of enzymes and other high-value bioproducts. This work evaluates the production of cellulase enzymes using glycerol for high cell density growth of Trichoderma harzianum followed by induction with a cellulosic material. Firstly, the influence of the carbon source used in the pre-culture step was investigated in terms of total protein secretion and fungal morphology. Enzymatic productivity was then determined for cultivation strategies using different types and concentrations of carbon source, as well as different feeding procedures (batch and fed-batch). The best strategy for cellulase production was then further studied on a larger scale using a stirred tank bioreactor. The proposed strategy for cellulase production, using glycerol to achieve high cell density growth followed by induction with pretreated sugarcane bagasse, achieved enzymatic activities up to 2.27 ± 0.37 FPU/mL, 106.40 ± 8.87 IU/mL, and 9.04 ± 0.39 IU/mL of cellulase, xylanase, and β-glucosidase, respectively. These values were 2 times higher when compared to the control experiments using glucose instead of glycerol. This novel strategy proved to be a promising approach for improving cellulolytic enzymes production, and could potentially contribute to adding value to biomass within the biofuels sector.

  12. ETHANOL DEHYDRATION IN PACKED DISTILLATION COLUMN USING GLYCEROL AS ENTRAINER: EXPERIMENTS AND HETP EVALUATION

    Directory of Open Access Journals (Sweden)

    W. L. R. Souza

    Full Text Available Abstract The ethanol-water separation is very important because ethanol is widely applied in the chemical industry and its use as a fuel can reduce the pollution emitted to the air. However, anhydrous ethanol production using conventional distillation is impossible, at atmospheric pressure, due to the presence of an azeotrope. In the present work, experimental tests were carried out in order to evaluate the use of glycerol as an entrainer, in substitution of ethylene glycol in an extractive distillation. The use of glycerol is motivated by the biodiesel production units, due to the fact that it is the main byproduct and a new market is necessary to consume its overproduction. The experiments were carried out in a distillation column packed with Raschig rings, varying the glycerol/feed (ethanol and water ratio, S/F, from 0.5 to 0.9. The samples were analyzed using a digital densimeter. The results showed that glycerol was effective to promote ethanol dehydration and the presence of an azeotrope was not observed using a solvent to feed ratio (S/F equal to 0.9. Some empirical correlations were investigated to evaluate the HETP (Height Equivalent to a Theoretical Plate, and the results provided a useful tool for designing a packed bed column for ethanol-water separation.

  13. Wet oxidation of glycerol into fine organic acids: catalyst selection and kinetic evaluation

    Directory of Open Access Journals (Sweden)

    J. E. N. Brainer

    2014-12-01

    Full Text Available The liquid phase oxidation of glycerol was performed producing fine organic acids. Catalysts based on Pt, Pd and Bi supported on activated carbon were employed to perform the conversion of glycerol into organic acids at 313 K, 323 K and 333 K, under atmospheric pressure (1.0 bar, in a mechanically agitated slurry reactor (MASR. The experimental results indicated glycerol conversions of 98% with production of glyceric, tartronic and glycolic acids, and dihydroxyacetone. A yield of glyceric acid of 69.8%, and a selectivity of this compound of 70.6% were reached after 4 h of operation. Surface mechanisms were proposed and rate equations were formulated to represent the kinetic behavior of the process. Selective formation of glyceric acid was observed, and the kinetic parameter values indicated the lowest activation energy (38.5 kJ/mol for its production reaction step, and the highest value of the adsorption equilibrium constant of the reactant glycerol (10-4 dm³/mol.

  14. Alternative Glycerol Balance Strategies among Saccharomyces Species in Response to Winemaking Stress

    Czech Academy of Sciences Publication Activity Database

    Pérez-Torrado, R.; Oliveira, B. M.; Zemančíková, Jana; Sychrová, Hana; Querol, A.

    2016-01-01

    Roč. 7, Mar 31 (2016), s. 435 ISSN 1664-302X R&D Projects: GA ČR(CZ) GA15-03708S EU Projects: European Commission(XE) 264717 - CORNUCOPIA Institutional support: RVO:67985823 Keywords : Saccharomyces * stress tolerance * glycerol * gene expression Subject RIV: EE - Microbiology, Virology Impact factor: 4.076, year: 2016

  15. An improved synthesis of 14C labelled glycerol using sodium borohydride

    International Nuclear Information System (INIS)

    Chander, H.; Ramamurthy, T.V.; Viswanathan, K.V.

    1987-01-01

    [1- 14 C]Glyceric acid has been reduced to [1(3)- 14 C]glycerol in high yields via the methyl ester of [1- 14 C]glyceric acid by sodium borohydride in the presence of t-butyl alcohol and methanol. The importance of the procedure is highlighted in relation to other procedures involving lithium aluminium hydride reduction. (author)

  16. Catalytic reforming of glycerol in supercritical water over bimetallic Pt-Ni catalyst

    NARCIS (Netherlands)

    Chakinala, A.G.; van Swaaij, Willibrordus Petrus Maria; Kersten, Sascha R.A.; de Vlieger, Dennis; Seshan, Kulathuiyer; Brilman, Derk Willem Frederik

    2013-01-01

    Catalytic reforming of pure glycerol for the production of hydrogen at low temperature and short residence times in supercritical water was investigated using a bimetallic Pt–Ni catalyst supported on alumina. Initial tests were carried out to study the reforming activity of bimetallic Pt–Ni

  17. Chiral gas chromatography for the determination of 1,2-O-isopropylidene-sn-glycerol stereoisomers

    NARCIS (Netherlands)

    Dröge, M.J; Bos, R.; Woerdenbag, H.J.; Quax, Wim; Droge, MJ

    2003-01-01

    A stereospecific gas chromatography (GC) method using a (6-O-tButyldimethylsilyl-2,3-di-O-methyl)-beta-cyclodextrin as the chiral stationary phase has been developed and validated for the determination of the enantiomers of 1,2-O-isopropylidene-sn-glycerol (IPG), an important chiral synthon, in

  18. Synergetic hydrothermal co-liquefaction of crude glycerol and aspen wood

    DEFF Research Database (Denmark)

    Pedersen, Thomas Helmer; Jasiunas, Lukas; Casamassima, Luca

    2015-01-01

    quality were all invariant to the reaction temperature. By increasing the crude glycerol to aspen wood mass ratio from 0:1 to 3:1, char yield was decreased from 18.3% (only aspen wood) to 3.4%. Furthermore, the biocrude quality in terms of the effective hydrogen-to-carbon ratio (H/Ceff) was significantly...

  19. Ice Recrystallization Inhibiting Polymers Enable Glycerol-Free Cryopreservation of Micro-organisms.

    Science.gov (United States)

    Hasan, Muhammad; Fayter, Alice E R; Gibson, Matthew I

    2018-06-22

    All modern molecular biology and microbiology is underpinned not only by the tools to handle and manipulate microorganisms, but also those to store, bank and transport them. Glycerol is the current gold-standard cryoprotectant but it is intrinsically toxic to most micro-organisms: only a fraction of cells survive freezing and the presence of glycerol can impact down-stream applications and assays. Extremophile organisms survive repeated freeze/thaw cycles by producing antifreeze proteins which are potent ice recrystallization inhibitors. Here we introduce a new concept for the storage/transport of micro-organisms by using ice recrystallization inhibiting poly(vinyl alcohol) in tandem with poly(ethylene glycol). This cryopreserving formulation is shown to result in a 4-fold increase in E. coli yield post-thaw, compared to glycerol, utilizing lower concentrations, with successful cryopreservation at just 1.1 weight percent of additive. The mechanism of protection is demonstrated to be linked to inhibiting ice recrystallization (by comparison to a recombinant antifreeze protein) but also to the significantly lower toxicity of the polymers compared to glycerol. Optimized formulations are presented and shown to be broadly applicable to the cryopreservation of a panel of Gram negative, Gram positive and Mycobacteria strains. This represents a step-change in how micro-organisms will be stored by the design of new macromolecular ice growth inhibitors; it should enable a transition from traditional solvent-based to macromolecular microbiology storage methods.

  20. Synthesis of substituted 1,3-diesters of glycerol using wittig chemistry.

    Science.gov (United States)

    Lowe, Henry I C; Toyang, Ngeh J; Watson, Charah T; Bryant, Joseph

    2014-05-01

    1,3-di-O-Cinnamoyl-glycerol is a natural compound isolated from a Jamaican medicinal plant commonly referred to as Ball moss (Tillandsia recurvata). The synthesis of this compound was achieved via a Wittig chemistry process. The synthetic approach started with acylation of a di-protected glycerol with cinnamoyl chloride, deprotection of the glycerol moiety, reaction of the primary alcohol with bromo acetylbromide followed by treatment with triphenyl phosphine to give the corresponding phosphonium bromide. The phosphonium bromide was then converted in situ to the Wittig reagent which is the basis for a novel route to 1,3-di-O-cinnamoyl glycerol. Four analogs were also synthesized, three of which are new and are being reported in this article for the first time. The new compounds include 3-(3,4-diemthoxy-phenyl)-acrylic acid 2-hydroxy-3-(3-ptolyl-acryloyloxy)-propyl ester (3), 2-acetoxy-5-((E)-3-(3-((E)-3-(3,4-dimethoxyphenyl)acryloyloxy)-2-hydropropoxy)-3-oxoprop- 1-enyl)benzoic acid (4) and 4-((E)-3-(3-((E)-3-(3,4-dimethoxyphenyl)acryloyloxy)-2-hydropropoxy)-3-oxoprop-1-enyl)benzoic acid (5). The compounds showed no activity in our anticancer assay.

  1. Inhibition of mitochondrial glycerol-3-phosphate dehydrogenase by alpha-tocopheryl succinate

    Czech Academy of Sciences Publication Activity Database

    Rauchová, Hana; Vokurková, Martina; Drahota, Zdeněk

    2014-01-01

    Roč. 53, AUG (2014), s. 409-413 ISSN 1357-2725 R&D Projects: GA ČR(CZ) GAP304/12/0259 Institutional support: RVO:67985823 Keywords : brown adipose tissue mitochondria * oxygen consumption * glycerol-3-phosphate * succinate * reactive oxygen species Subject RIV: ED - Physiology Impact factor: 4.046, year: 2014

  2. Coupling of glycerol processing with Fischer-Tropsch synthesis for production of liquid fuels

    DEFF Research Database (Denmark)

    Simonetti, D.A.; Rass-Hansen, Jeppe; Kunkes, E.L.

    2007-01-01

    Liquid alkanes can be produced directly from glycerol by an integrated process involving catalytic conversion to H-2/CO gas mixtures (synthesis gas) combined with Fischer-Tropsch synthesis. Synthesis gas can be produced at high rates and selectivities suitable for Fischer-Tropsch synthesis (H-2/CO...... between 1.0 and 1.6) from concentrated glycerol feed solutions at low temperatures (548 K) and high pressures (1-17 bar) over a 10 wt% Pt-Re/C catalyst with an atomic Pt : Re ratio of 1 : 1. The primary oxygenated hydrocarbon intermediates formed during conversion of glycerol to synthesis gas are ethanol...... in the liquid organic effluent stream and increasing the selectivity to C5+ alkanes by a factor of 2 ( from 0.30 to 0.60). Catalytic conversion of glycerol and Fischer-Tropsch synthesis were coupled in a two-bed reactor system consisting of a Pt-Re/C catalyst bed followed by a Ru/TiO2 catalyst bed...

  3. Edible Film from the Pectin of Papaya Skin (The Study of Cassava Starch and Glycerol Addition)

    Science.gov (United States)

    Rosida; Sudaryati; Yahya, A. M.

    2018-01-01

    The production of edible cooking made from the pectin of papaya skin with cassava starch and glycerol adition had been studied. The usage of pectin of papaya skin was one way to use papaya skin waste in order to raise its economic value. The aim of this study was to study the effect of cassava starch and glycerol concentration on the product qualities and to determine the the best treatment in making a good quality adible film and acceptable by the consumer. This research used completely randomized design in factorial patern with two factors. The first factor was cassava starch concentration (25%, 35% and 45%) and the second factor was glycerol concentration (20 %, 15% and 10). The data were analyzed by Analysis of Variance (Anova) and Duncan’s Multiple Range Test to detect the difference between the treatment. The best treatment was 25% cassava starch addition and 10% glycerol concentration which produced edible film which had moisture content of 21.16%, thickness of 0.023 mm, tensile strength of 1.900 N, elasticity of 14.223%, and vapor transmission rate of 116.963 g/m2/24 hours. So the production of edible film from papaya skin pectin was potential to be developed.

  4. Effect of Coconut, Sisal and Jute Fibers on the Properties of Starch/Gluten/Glycerol Matrix

    Science.gov (United States)

    Coconut, sisal and jute fibers were added as reinforcement materials in a biodegradable polymer matrix comprised of starch/gluten/glycerol. The content of fibers used in the composites varied from 5% to 30% by weight of the total polymers (starch and gluten). Materials were processed in a Haake torq...

  5. The role of glycerol transporters in yeast cells in various physiological and stress conditions

    Czech Academy of Sciences Publication Activity Database

    Dušková, Michala; Borovikova, D.; Herynková, Pavla; Rapoport, A.; Sychrová, Hana

    2015-01-01

    Roč. 362, č. 3 (2015), s. 1-8 ISSN 0378-1097 R&D Projects: GA ČR(CZ) GAP503/10/0307 Institutional support: RVO:67985823 Keywords : Saccharomyces cerevisiae * glycerol transport * desiccation * osmotic stress Subject RIV: EE - Microbiology, Virology Impact factor: 1.858, year: 2015

  6. Liquefaction behaviors of bamboo residues in a glycerol-based solvent using microwave energy

    Science.gov (United States)

    Jiulong Xie; Chung-Yun Hse; Todd F. Shupe; Jinqiu Qi; Hui Pan

    2014-01-01

    Liquefaction of bamboo was performed in glycerol–methanol as co-solvent using microwave energy and was evaluated by characterizing the liquefied residues. High efficiency conversion of bamboo was achieved under mild reaction conditions. Liquefaction temperature and time interacted to affect the liquefaction reaction. Fourier transform infrared analyzes of the residues...

  7. Glycerol as high-permittivity liquid filler in dielectric silicone elastomers

    DEFF Research Database (Denmark)

    Mazurek, Piotr Stanislaw; Yu, Liyun; Gerhard, R.

    2016-01-01

    A recently reported novel class of elastomers was tested with respect to its dielectric properties. The new elastomer materialis based on a commercially available poly(dimethylsiloxane) composition, which has been modified by embedding glycerol droplets intoits matrix. The approach has two major ......, and the applicability ofthe models is discussed. VC 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44153....

  8. The effect of glycerol on regional cerebral blood flow, blood volume and oxygen metabolism

    International Nuclear Information System (INIS)

    Ishikawa, Masatsune; Kikuchi, Haruhiko; Nagata, Izumi; Yamagata, Sen; Taki, Waro; Kobayashi, Akira; Yonekura, Yoshiharu; Nishizawa, Sadahiko.

    1989-01-01

    Using positron emission tomography with 15 O-labelled CO 2 , O 2 and CO gases, the effects of glycerol on regional cerebral blood flow (CBF), blood volume (CBV) and oxygen metabolism (CMRO 2 ) were investigated in 6 patients with meningioma accompanying peritumoral brain edema. The same study was done in 5 normal volunteers. The changes of blood gases, hematocrit and hemoglobin were also examined. After a drip infusion of glycerol, the regional CBF increased not only in the peritumoral cortex and white matter but also in the intact cortex and white matter on the contralateral side. The increase of CBF was extensive and substantially there were no regional differences. In contrast, the changes of CMRO 2 were not significant. This was derived from the increase in oxygen extraction fraction throughout extensive areas including the peritumoral area. There were no changes in CBV. Hematocrit and hemoglobin decreased to a small degree. In the normal volunteers, the same findings were noted. Thus, glycerol increases the functional reserve for cerebral oxygen metabolism, not only in the peritumoral regions but also in the intact regions. The effects of glycerol on hemodynamics and metabolism were discussed with reference to some differences from mannitol. (author)

  9. Mathematical modeling and experimental validation of Phaeodactylum tricornutum microalgae growth rate with glycerol addition

    Energy Technology Data Exchange (ETDEWEB)

    Morais, Keli Cristiane Correia; Ribeiro, Robert Luis Lara; Santos, Kassiana Ribeiro dos; Mariano, Andre Bellin [Mariano Center for Research and Development of Sustainable Energy (NPDEAS), Curitiba, PR (Brazil); Vargas, Jose Viriato Coelho [Departament of Mechanical Engineering, Federal University of Parana (UFPR) Curitiba, PR (Brazil)

    2010-07-01

    The Brazilian National Program for Bio fuel Production has been encouraging diversification of feedstock for biofuel production. One of the most promising alternatives is the use of microalgae biomass for biofuel production. The cultivation of microalgae is conducted in aquatic systems, therefore microalgae oil production does not compete with agricultural land. Microalgae have greater photosynthetic efficiency than higher plants and are efficient fixing CO{sub 2}. The challenge is to reduce production costs, which can be minimized by increasing productivity and oil biomass. Aiming to increase the production of microalgae biomass, mixotrophic cultivation, with the addition of glycerol has been shown to be very promising. During the production of biodiesel from microalgae there is availability of glycerol as a side product of the transesterification reaction, which could be used as organic carbon source for microalgae mixotrophic growth, resulting in increased biomass productivity. In this paper, to study the effect of glycerol in experimental conditions, the batch culture of the diatom Phaeodactylum tricornutum was performed in a 2-liter flask in a temperature and light intensity controlled room. During 16 days of cultivation, the number of cells per ml was counted periodically in a Neubauer chamber. The calculation of dry biomass in the control experiment (without glycerol) was performed every two days by vacuum filtration. In the dry biomass mixotrophic experiment with glycerol concentration of 1.5 M, the number of cells was assessed similarly in the 10{sup th} and 14{sup th} days of cultivation. Through a volume element methodology, a mathematical model was written to calculate the microalgae growth rate. It was used an equation that describes the influence of irradiation and concentration of nutrients in the growth of microalgae. A simulation time of 16 days was used in the computations, with initial concentration of 0.1 g l{sup -1}. In order to compare

  10. 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.

  11. Criteria for Quick and Consistent Synthesis of Poly(glycerol sebacate) for Tailored Mechanical Properties.

    Science.gov (United States)

    Li, Xinda; Hong, Albert T-L; Naskar, Nilanjon; Chung, Hyun-Joong

    2015-05-11

    Poly(glycerol sebacate) (PGS) and its derivatives make up an attractive class of biomaterial owing to their tunable mechanical properties with programmable biodegradability. In practice, however, the application of PGS is often hampered by frequent inconsistency in reproducing process conditions. The inconsistency stems from the volatile nature of glycerol during the esterification process. In this study, we suggest that the degree of esterification (DE) can be used to predict precisely the physical status, the mechanical properties, and the degradation of the PGS materials. Young's modulus is shown to linearly increase with DE, which is in agreement with an entropic spring theory of rubbers. To provide a processing guideline for researchers, we also provide a physical status map as a function of curing temperature and time. The amount of glycerol loss, obtainable by monitoring the evolution of the total mass loss and the DE during synthesis, is shown to make the predictions even more precise. We expect that these strategies can be applicable to different categories of polymers that involve condensation polymerization with the volatility of the reactants. In addition, we demonstrate that microwave-assisted prepolymerization is a time- and energy-efficient pathway to obtain PGS. For example, 15 min of microwave time is shown to be as efficient as prepolymerization in nitrogen atmosphere for 6 h at 130 °C. The quick synthesis method, however, causes a severe evaporation of glycerol, resulting in a large distortion in the monomer ratio between glycerol and sebacic acid. Consequently, more rigid PGS is produced under a similar curing condition compared to the conventional prepolymerization method. Finally, we demonstrate that the addition of molecularly rigid cross-linking agents and network-structured inorganic nanoparticles are also effective in enhancing the mechanical properties of the PGS-derived materials.

  12. Life cycle assessment of hydrogen and power production by supercritical water reforming of glycerol

    International Nuclear Information System (INIS)

    Galera, S.; Gutiérrez Ortiz, F.J.

    2015-01-01

    Highlights: • The environmental performance of the supercritical water reforming (SCWR) of glycerol was assessed. • Biogenic CO 2 emissions allowed quantifying a realistic GHG inventory of 3.8 kg CO 2 -eq/kg H 2 . • The environmental profile of SCWR process was compared to those of other technologies. • A good environmental performance of H 2 and power production by SCWR of glycerol was obtained. - Abstract: The environmental performance of hydrogen and electricity production by supercritical water reforming (SCWR) of glycerol was evaluated following a Life Cycle Assessment (LCA) approach. The heat-integrated process was designed to be energy self-sufficient. Mass and energy balances needed for the study were performed using Aspen Plus 8.4, and the environmental assessment was carried out through SimaPro 8.0. CML 2000 was selected as the life cycle impact assessment method, considering as impact categories the global warming, ozone layer depletion, abiotic depletion, photochemical oxidant formation, eutrophication, acidification, and cumulative energy demand. A distinction between biogenic and fossil CO 2 emissions was done to quantify a more realistic GHG inventory of 3.77 kg CO 2 -eq per kg H 2 produced. Additionally, the environmental profile of SCWR process was compared to other H 2 production technologies such as steam methane reforming, carbon gasification, water electrolysis and dark fermentation among others. This way, it is shown that SCWR of glycerol allows reducing greenhouse gas emissions and obtaining a favorable positive life cycle energy balance, achieving a good environmental performance of H 2 and power production by SCWR of glycerol

  13. Structure of glycerol-3-phosphate dehydrogenase, an essential monotopic membrane enzyme involved in respiration and metabolism

    International Nuclear Information System (INIS)

    Yeh, Joanne I.; Chinte, Unmesh; Du, Shoucheng

    2008-01-01

    Sn-glycerol-3-phosphate dehydrogenase (GlpD) is an essential membrane enzyme, functioning at the central junction of respiration, glycolysis, and phospholipid biosynthesis. Its critical role is indicated by the multitiered regulatory mechanisms that stringently controls its expression and function. Once expressed, GlpD activity is regulated through lipid-enzyme interactions in Escherichia coli. Here, we report seven previously undescribed structures of the fully active E. coli GlpD, up to 1.75 (angstrom) resolution. In addition to elucidating the structure of the native enzyme, we have determined the structures of GlpD complexed with substrate analogues phosphoenolpyruvate, glyceric acid 2-phosphate, glyceraldehyde-3-phosphate, and product, dihydroxyacetone phosphate. These structural results reveal conformational states of the enzyme, delineating the residues involved in substrate binding and catalysis at the glycerol-3-phosphate site. Two probable mechanisms for catalyzing the dehydrogenation of glycerol-3-phosphate are envisioned, based on the conformational states of the complexes. To further correlate catalytic dehydrogenation to respiration, we have additionally determined the structures of GlpD bound with ubiquinone analogues menadione and 2-n-heptyl-4-hydroxyquinoline N-oxide, identifying a hydrophobic plateau that is likely the ubiquinone-binding site. These structures illuminate probable mechanisms of catalysis and suggest how GlpD shuttles electrons into the respiratory pathway. Glycerol metabolism has been implicated in insulin signaling and perturbations in glycerol uptake and catabolism are linked to obesity in humans. Homologs of GlpD are found in practically all organisms, from prokaryotes to humans, with >45% consensus protein sequences, signifying that these structural results on the prokaryotic enzyme may be readily applied to the eukaryotic GlpD enzymes.

  14. Study of Catalyst Variation Effect in Glycerol Conversion Process to Hydrogen Gas by Steam Reforming

    Science.gov (United States)

    Widayat; Hartono, R.; Elizabeth, E.; Annisa, A. N.

    2018-04-01

    Along with the economic development, needs of energy being increase too. Hydrogen as alternative energy has many usages. Besides that, hydrogen is one source of energy that is a clean fuel, but process production of hydrogen from natural gas as a raw material has been used for a long time. Therefore, there is need new invention to produce hydrogen from the others raw material. Glycerol, a byproduct of biodiesel production, is a compound which can be used as a raw material for hydrogen production. By using glycerol as a raw material of hydrogen production, we can get added value of glycerol as well as an energy source solution. The process production of hydrogen by steam reforming is a thermochemical process with efficiency 70%. This process needs contribution of catalyst to improve its efficiency and selectivity of the process. In this study will be examined the effect variation of catalyst for glycerol conversion process to hydrogen by steam reforming. The method for catalyst preparation was variation of catalyst impregnation composition, catalyst calcined with difference concentration of hydrochloric acid and calcined with difference hydrochloric acid ratio. After that, all of catalyst which have been prepared, used for steam reforming process for hydrogen production from glycerol as a raw material. From the study, the highest yield of hydrogen gas showed in the process production by natural zeolite catalyst with 1:15 Hydrochloric acid ratio was 42.28%. Hydrogen yield for 2M calcined natural zeolite catalyst was 38.37%, for ZSM-5 catalyst was 15.83%, for 0.5M calcined natural zeolite was 13.09% and for ultrasonic natural zeolite was 11.43%. The lowest yield of hydrogen gas showed in catalyst 2Zn/ZSM-5 with 11.22%. This result showed that hydrogen yield product was affected by catalyst variation because of the catalyst has difference characteristic and difference catalytic activity after the catalyst preparation process.

  15. Borrelia burgdorferi requires glycerol for maximum fitness during the tick phase of the enzootic cycle.

    Directory of Open Access Journals (Sweden)

    Christopher J Pappas

    2011-07-01

    Full Text Available Borrelia burgdorferi, the spirochetal agent of Lyme disease, is a vector-borne pathogen that cycles between a mammalian host and tick vector. This complex life cycle requires that the spirochete modulate its gene expression program to facilitate growth and maintenance in these diverse milieus. B. burgdorferi contains an operon that is predicted to encode proteins that would mediate the uptake and conversion of glycerol to dihydroxyacetone phosphate. Previous studies indicated that expression of the operon is elevated at 23°C and is repressed in the presence of the alternative sigma factor RpoS, suggesting that glycerol utilization may play an important role during the tick phase. This possibility was further explored in the current study by expression analysis and mutagenesis of glpD, a gene predicted to encode glycerol 3-phosphate dehydrogenase. Transcript levels for glpD were significantly lower in mouse joints relative to their levels in ticks. Expression of GlpD protein was repressed in an RpoS-dependent manner during growth of spirochetes within dialysis membrane chambers implanted in rat peritoneal cavities. In medium supplemented with glycerol as the principal carbohydrate, wild-type B. burgdorferi grew to a significantly higher cell density than glpD mutant spirochetes during growth in vitro at 25°C. glpD mutant spirochetes were fully infectious in mice by either needle or tick inoculation. In contrast, glpD mutants grew to significantly lower densities than wild-type B. burgdorferi in nymphal ticks and displayed a replication defect in feeding nymphs. The findings suggest that B. burgdorferi undergoes a switch in carbohydrate utilization during the mammal to tick transition. Further, the results demonstrate that the ability to utilize glycerol as a carbohydrate source for glycolysis during the tick phase of the infectious cycle is critical for maximal B. burgdorferi fitness.

  16. Synthesis of biodegradable plastic from tapioca with N-Isopropylacrylamid and chitosan using glycerol as plasticizer

    Science.gov (United States)

    Syaubari; Safwani, S.; Riza, M.

    2018-04-01

    One of natural polymers that can be used as raw material in the manufacture of biodegradable plastic is tapioca and chitosan. The addition of other compounds such as glycerol as plasticizer is to improve the characteristics of the plastic that already produced. N- Isopropylacrylamid (NIPAm) is an organic compound that can be synthesized into a polymer or polymer grafting which also biodegradable too. This research aims tostudy the synthesis of biodegradable plastics from tapioca with the addition of chitosan, NIPAm, poly(NIPAm) and analyze the characteristics of biodegradable plastics that already produced. This research was done in three stages, there are (1) polymerization NIPAm, (2) the grafting of chitosan-poly NIPAm and (3) the synthesis of biodegradable plastics from starch mixture with variation of addition chitosan, NIPAm, poly(NIPAm), chitosan-graft-poly(NIPAm) and also variations of glycerol as plasticizer. The results of this research is a thin sheet of plastic which is will get analyzed for the characteristics of functional groups, mechanical, morphological and its biodegradability. FTIR spectra showed the grafting process with the new group formation of CO single-bond at 850 cm-1. Plastic with the addition of NIPAm and 1 ml glycerol has the highest tensile strength value about 31.1 MPa. Plastic with poly(NIPAm) and 4 ml glycerol produces the highest elongation value about 153.72%. Plastic with Chitosan-graft-poly(NIPAm) with 1 ml glycerol has the longest biodegradation because of the small mass-loss for six weeks which is about 6.6%.

  17. 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.

  18. Using crude glycerol and thin stillage for the production of microbial lipids through the cultivation of Rhodotorula glutinis.

    Science.gov (United States)

    Yen, Hong-Wei; Yang, Ya-Chun; Yu, Yi-Huan

    2012-10-01

    Single cell oils (SCO) produced from oleaginous microorganisms are a potential alternative oil feedstock for biodiesel production. The worldwide production of glycerol, a 10% (w/w) byproduct produced in the transesterfication process of oils converted to biodiesel, is increasing as more biodiesel is being produced. For the purposes of cost reduction, crude glycerol was regarded as a suitable carbon source for the cultivation of Rhodotorula glutinis. In addition to using renewable crude glycerol, waste solution collected from the brewing company (called thin stillage) was adopted as a substitute to replace a costly nitrogen source used in the medium. The results of using mixture of crude glycerol and thin stillage indicated about a 27% increase in total biomass as compared to that of using crude glycerol with a standard medium. Using glycerol instead of glucose as the carbon source could also alter the lipid profile, resulting in an increase in linolenic acid (C18:2) to comprise over 20% of the total lipid. Successfully using renewable crude glycerol and thin stillage for the cultivation of oleaginous microorganisms could greatly enhance the economic competition of biodiesel produced from SCO. Copyright © 2012 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  19. Preliminary Evaluation of Glyceric Acid-producing Ability of Acidomonas methanolica NBRC104435 from Glycerol Containing Methanol.

    Science.gov (United States)

    Sato, Shun; Kitamoto, Dai; Habe, Hiroshi

    2017-06-01

    Some acetic acid bacteria produce large amounts of glyceric acid (GA) from glycerol in culture broth. However, methanol, which is a major contaminant of raw glycerol derived from the biodiesel fuel industry, sharply decreases cell growth and GA production [AMB Express, 3, 20, 2013]. Thus, we evaluated the methylotrophic acetic acid bacterium Acidomonas methanolica NBRC104435 for its ability to produce GA from glycerol containing methanol. This strain accumulated GA in its culture broth when 1-3 wt% glycerol was available as a carbon source. We observed improved cell growth and GA accumulation when 1 vol% methanol was added to the 3-5 wt% glycerol medium. The maximum concentration of GA was 12.8 g/L in medium containing 3 wt% glycerol plus 1 vol% methanol. In addition, the enantiomeric excess (ee) of the GA produced was revealed to be 44%, indicating that this strain converted glycerol to d-GA with a lower enantioselectivity than other acetic acid bacteria, which had 70-99% ee.

  20. Biohydrogen and Bioethanol Production from Biodiesel-Based Glycerol by Enterobacter aerogenes in a Continuous Stir Tank Reactor

    Directory of Open Access Journals (Sweden)

    Rujira Jitrwung

    2015-05-01

    Full Text Available Crude glycerol from the biodiesel manufacturing process is being produced in increasing quantities due to the expanding number of biodiesel plants. It has been previously shown that, in batch mode, semi-anaerobic fermentation of crude glycerol by Enterobacter aerogenes can produce biohydrogen and bioethanol simultaneously. The present study demonstrated the possible scaling-up of this process from small batches performed in small bottles to a 3.6-L continuous stir tank reactor (CSTR. Fresh feed rate, liquid recycling, pH, mixing speed, glycerol concentration, and waste recycling were optimized for biohydrogen and bioethanol production. Results confirmed that E. aerogenes uses small amounts of oxygen under semi-anaerobic conditions for growth before using oxygen from decomposable salts, mainly NH4NO3, under anaerobic condition to produce hydrogen and ethanol. The optimal conditions were determined to be 500 rpm, pH 6.4, 18.5 g/L crude glycerol (15 g/L glycerol and 33% liquid recycling for a fresh feed rate of 0.44 mL/min. Using these optimized conditions, the process ran at a lower media cost than previous studies, was stable after 7 days without further inoculation and resulted in yields of 0.86 mol H2/mol glycerol and 0.75 mol ethanol/mole glycerol.

  1. Biohydrogen and Bioethanol Production from Biodiesel-Based Glycerol by Enterobacter aerogenes in a Continuous Stir Tank Reactor

    Science.gov (United States)

    Jitrwung, Rujira; Yargeau, Viviane

    2015-01-01

    Crude glycerol from the biodiesel manufacturing process is being produced in increasing quantities due to the expanding number of biodiesel plants. It has been previously shown that, in batch mode, semi-anaerobic fermentation of crude glycerol by Enterobacter aerogenes can produce biohydrogen and bioethanol simultaneously. The present study demonstrated the possible scaling-up of this process from small batches performed in small bottles to a 3.6-L continuous stir tank reactor (CSTR). Fresh feed rate, liquid recycling, pH, mixing speed, glycerol concentration, and waste recycling were optimized for biohydrogen and bioethanol production. Results confirmed that E. aerogenes uses small amounts of oxygen under semi-anaerobic conditions for growth before using oxygen from decomposable salts, mainly NH4NO3, under anaerobic condition to produce hydrogen and ethanol. The optimal conditions were determined to be 500 rpm, pH 6.4, 18.5 g/L crude glycerol (15 g/L glycerol) and 33% liquid recycling for a fresh feed rate of 0.44 mL/min. Using these optimized conditions, the process ran at a lower media cost than previous studies, was stable after 7 days without further inoculation and resulted in yields of 0.86 mol H2/mol glycerol and 0.75 mol ethanol/mole glycerol. PMID:25970750

  2. Effect of sorbitol and glycerol on the stability of trypsin and difference between their stabilization effects in the various solvents.

    Science.gov (United States)

    Pazhang, Mohammad; Mehrnejad, Faramarz; Pazhang, Yaghub; Falahati, Hanieh; Chaparzadeh, Nader

    2016-01-01

    The effect of glycerol and sorbitol on the stability of porcine pancreas trypsin was investigated in this work. Molecular dynamics simulation and thermostability results showed that trypsin has two flexible regions, and polyols (sorbitol and glycerol) stabilize the enzyme by decreasing the flexibility of these regions. Radial distribution function results exhibited that sorbitol and glycerol were excluded from the first water layer of the enzyme, therefore decrease the flexibility of the regions by preferential exclusion. Also, results showed that the stabilization effect of sorbitol is more than glycerol. This observation could be because of the larger decrease in the fluctuations of trypsin in the presence of sorbitol. We also examined the role of solvent's hydrophobicity in enzyme stabilization by sorbitol and glycerol. To do so, the thermostability of trypsin was evaluated in the presence of solvents with different hydrophobicity (methanol, ethanol, isopropanol and n-propanol) in addition to the polyols. Our results depicted that glycerol is a better stabilizer than sorbitol in the presence of hydrophobic solvents (n-propanol), whereas sorbitol is a better stabilizer than glycerol in the presence of hydrophilic solvents (methanol). © 2015 International Union of Biochemistry and Molecular Biology, Inc.

  3. Design and development of low cost polyurethane biopolymer based on castor oil and glycerol for biomedical applications.

    Science.gov (United States)

    Tan, A C W; Polo-Cambronell, B J; Provaggi, E; Ardila-Suárez, C; Ramirez-Caballero, G E; Baldovino-Medrano, V G; Kalaskar, D M

    2018-02-01

    In the current study, we present the synthesis of novel low cost bio-polyurethane compositions with variable mechanical properties based on castor oil and glycerol for biomedical applications. A detailed investigation of the physicochemical properties of the polymer was carried out by using mechanical testing, ATR-FTIR, and X-ray photoelectron spectroscopy (XPS). Polymers were also tested in short term in-vitro cell culture with human mesenchymal stem cells to evaluate their biocompatibility for potential applications as biomaterial. FTIR analysis confirmed the synthesis of castor oil and glycerol based PU polymers. FTIR also showed that the addition of glycerol as co-polyol increases crosslinking within the polymer backbone hence enhancing the bulk mechanical properties of the polymer. XPS data showed that glycerol incorporation leads to an enrichment of oxidized organic species on the surface of the polymers. Preliminary investigation into in vitro biocompatibility showed that serum protein adsorption can be controlled by varying the glycerol content with polymer backbone. An alamar blue assay looking at the metabolic activity of the cells indicated that castor oil based PU and its variants containing glycerol are non-toxic to the cells. This study opens an avenue for using low cost bio-polyurethane based on castor oil and glycerol for biomedical applications. © 2017 The Authors Biopolymers Published by Wiley Periodicals, Inc.

  4. Construction of an alternative glycerol-utilization pathway for improved β-carotene production in Escherichia coli.

    Science.gov (United States)

    Guo, Jin-Ying; Hu, Kun-Le; Bi, Chang-Hao; Li, Qing-Yan; Zhang, Xue-Li

    2018-05-11

    Glycerol, which is an inevitable by-product of biodiesel production, is an ideal carbon source for the production of carotenoids due to its low price, good availability and chemically reduced status, which results in a low requirement for additional reducing equivalents. In this study, an alternative carbon-utilization pathway was constructed in Escherichia coli to enable more efficient β-carotene production from glycerol. An aldehyde reductase gene (alrd) and an aldehyde dehydrogenase gene (aldH) from Ralstonia eutropha H16 were integrated into the E. coli chromosome to form a novel glycerol-utilization pathway. The β-carotene specific production value was increased by 50% after the introduction of alrd and aldH. It was found that the glycerol kinase gene (garK), alrd and aldH were the bottleneck of the alternative glycerol metabolic pathway, and modulation of garK gene with an mRS library further increased the β-carotene specific production value by 13%. Finally, co-modulation of genes in the introduced aldH-alrd operon led to 86% more of β-carotene specific production value than that of the strain without the alternative glycerol-utilization pathway and the glycerol-utilization rate was also increased. In this work, β-carotene production of E. coli was significantly improved by constructing and optimizing an alternative glycerol-utilization pathway. This strategy can potentially be used to improve the production of other isoprenoids using glycerol as a cheap and abundant substrate, and therefore has industrial relevance.

  5. Valorisation of crude glycerol through biological conversion into bioplastics and biofuels in the frame of an FP7 project

    DEFF Research Database (Denmark)

    Varrone, Cristiano; Gavala, Hariklia N.

    a very low value, due to the impurities and contaminants, and the purification of glycerol is not a viable option for the biodiesel industry anymore. In fact, crude glycerol is usually contaminated with water, methanol, soap, oil, and other compounds deriving from the transesterification process....... Therefore, the purification cost is high when converting crude glycerol by traditional chemistry methods. Setting up of biorefineries, that co-produce high-value compounds, has been considered a concrete solution to enhance economic viability of biodiesel production. The project: the overall aim...

  6. Glycerol: a brief history and their application in stereoselective syntheses; Glicerol: um breve historico e aplicacao em sinteses estereosseletivas

    Energy Technology Data Exchange (ETDEWEB)

    Beatriz, Adilson; Araujo, Yara J.K.; Lima, Denis Pires de, E-mail: adilson.beatriz@ufms.b [Universidade Federal de Mato Grosso do Sul (DQ/UFMS), Campo Grande, MS (Brazil). Dept. de Quimica

    2011-07-01

    Presently glycerol is considered a co-product of biodiesel industry. As the biodiesel production is exponentially increasing, glycerol generated from the transesterification of vegetable oils and fats is also being produced on a large scale, and turned out to be essential seeking for novel alternatives to the consumption of the extra volume, in crude and/or as derivatives high added value. This review mainly deals with chemical and enzymatic transformations of glycerol to obtain chiral building blocks for synthesis of pharmaceuticals and natural products. (author)

  7. 13C-NMR reveals glycerol as an unexpected major metabolite of the protozoan parasite Trichomonas vaginalis

    International Nuclear Information System (INIS)

    Chapman, A.; Lloyd, D.; Linstead, D.J.; Williams, J.

    1985-01-01

    13 C-NMR has been used to study the kinetics of the formation of metabolites from [l- 13 C]glucose in intact cells of Trichomonas vaginalis during anaerobic incubation. As well as the expected metabolites lactate and acetate, this technique revealed glycerol as an additional major product, present in amounts equimolar with acetate. The formation of glycerol is readily explained in terms of the need to maintain redox balance. This protozoan now joins the small group of organisms which are known to produce glycerol as a result of normal metabolic activities. (Auth.)

  8. Effects of Exercise Induced Dehydration and Glycerol Rehydration on Anaerobic Power in Male Collegiate Wrestlers.

    Science.gov (United States)

    McKenna, Zachary J; Gillum, Trevor L

    2017-11-01

    McKenna, ZJ and Gillum, TL. Effects of exercise induced dehydration and glycerol rehydration on anaerobic power in male collegiate wrestlers. J Strength Cond Res 31(11): 2965-2968, 2017-Wrestlers attempting to reach a specific weight class often use rapid weight loss (RWL). Rapid weight loss is associated with high levels of dehydration, which may hinder athletic performance. Thus, there is a need for wrestlers to optimize rehydration after achieving a specific weight. We sought to observe the effects of RWL on anaerobic power and the impact of glycerol on rehydration and power in male collegiate wrestlers (n = 7, 19.75 ± 1.67 years, 76.8 ± 4.32 kg, 11.6 ± 4.32% body fat, 59.9 ± 6.42 ml·kg·min). Subjects were assessed for body mass (BM), hydration, and mean power output (Wmean) before exercise (pre), immediately after exercise (3% dehydrated), and 60 minutes after exercise (rehydrated). Participants ran at 70% of V[Combining Dot Above]O2max in a heated room (30° C) until 3% BM loss (BML). Subjects rehydrated drinking either 26 ml·kg of water (control) or a 3% glycerol (treatment) solution containing 26 ml·kg of water and 1 g·kg of glycerol. Participants lost 3.00 ± 0.31% (control) and 2.89 ± 0.26% (treatment) of their BM from the pre- to dehydrated conditions. Wmean (control: 659.29 ± 79.12, 651.43 ± 70.71, 659.71 ± 82.78; treatment: 647.71 ± 110.64, 644.57 ± 118.15, 638.14 ± 100.71) did not differ across time (p = 0.87) nor condition (p = 0.80). In addition, glycerol had no significant impact on acute hydration (control: urine-specific gravity [SG] = 1.019 ± 0.010; treatment: SG = 1.017 ± 0.017). These data show that 3% BML did not impair anaerobic performance, and furthermore that glycerol proved ineffective for rehydration in a match like scenario for the competing wrestler.

  9. Stress corrosion cracking of austenitic stainless steel in glycerol solution and chloride solution at elevated temperature

    International Nuclear Information System (INIS)

    Haftirman; Maruhum Tua Lubis

    2009-01-01

    Stress Corrosion Cracking (SCC) is an environmentally assisted failure caused by exposure to a corrodant while under a sustained tensile stress. SCC is most often rapid, unpredictable and catastrophic. Failure can occur in as little as a few hours or take years to happen. Most alloys are susceptible to SCC in one or more environments requiring careful consideration of alloy type in component design. In aqueous chloride environments austenitic stainless steels and many nickel based alloys are known to perform poorly. One of products Oleo chemical is glycerol solution. Glycerol solution contains chloride with concentration 50 ppm - 150 ppm. Austenitic stainless steel is usually used in distillation construction tank and pipe line of glycerol. Material AISI 304 will be failure in this glycerol solution with this concentration in 5 years. In production process, concentration of chloride in glycerol becomes more than 150 ppm at temperature 150 degree Celsius. The reason is that the experiment I conducted in high chloride with concentration such as 6000 ppm, 9000 ppm, and 12000 ppm. The stress corrosion cracking of the austenitic stainless steels of types AISI 304, 316 and 316L in glycerol solution at elevated temperature 150 degree Celsius is investigated as a function variation of chloride concentration, namely 50, 6000, 9000 and 12000 ppm using a constant load method with two kinds of initial tensile stress as 50 % and 70 % yield strength. The experiment uses a spring loaded fixture type and is based on ASTM G49 for experiment method, and E292 for geometry of specimen. Pitting corrosion occurs on the surface specimen until the stress level reaches the ultimate strength. Pitting corrosion attack and depletion occur on the surface as initiation of SCC failure as the stress reaches the ultimate strength. Failure has occurred in catastrophic brittle fracture type of transgranular. AISI 304 was more susceptible for all conditions. In chloride solution with concentration of

  10. Hydrogen Production via Glycerol Dry Reforming over La-Ni/Al2O3 Catalyst

    Directory of Open Access Journals (Sweden)

    Kah Weng Siew

    2013-12-01

    Full Text Available Glycerol (a bio-waste generated from biodiesel production has been touted as a promising bio-syngas precursor via reforming route. Previous studies have indicated that carbon deposition is the major performance-limiting factor for nickel (Ni catalyst during glycerol steam reforming. In the current paper, dry (CO2-reforming of glycerol, a new reforming route was carried out over alumina (Al2O3-supported non-promoted and lanthanum-promoted Ni catalysts. Both sets of catalysts were synthesized via wet co-impregnation procedure. The physicochemical characterization of the catalyst showed that the promoted catalyst possessed smaller metal crystallite size, hence higher metal dispersion compared to the virgin Ni/Al2O3 catalyst. This was also corroborated by the surface images captured by the FESEM analysis. In addition, BET surface area measurement gave 92.05m²/g for non-promoted Ni catalyst whilst promoted catalysts showed an average of 1 to 6% improvement depending on the La loading. Reaction studies at 873 K showed that glycerol dry reforming successfully produced H2 with glycerol conversion and H2 yield that peaked at 9.7% and 25% respectively over 2wt% La content. The optimum catalytic performance by 2%La-Ni/Al2O3 can be attributed to the larger BET surface area and smaller crystallite size that ensured accessibility of active catalytic sites.  © 2013 BCREC UNDIP. All rights reservedReceived: 12nd May 2013; Revised: 7th October 2013; Accepted: 16th October 2013[How to Cite: Siew, K.W., Lee, H.C., Gimbun, J., Cheng, C.K. (2013. Hydrogen Production via Glycerol Dry Reforming over La-Ni/Al2O3 Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (2: 160-166. (doi:10.9767/bcrec.8.2.4874.160-166][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.2.4874.160-166

  11. Effect of mode of operation on hydrogen production from glycerol at thermal neutral conditions: Thermodynamic analysis

    Energy Technology Data Exchange (ETDEWEB)

    Pairojpiriyakul, Thirasak; Soottitantawat, Apinan; Arpornwichanop, Amornchai; Assabumrungrat, Suttichai [Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University (Thailand); Kiatkittipong, Worapon [Department of Chemical Engineering, Faculty of Engineering and Industrial Technology, Silpakorn University (Thailand); Wiyaratn, Wisitsree [Department of Production Technology Education, Faculty of Industrial Education and Technology, King Mongkut' s University of Technology Thonburi (Thailand); Laosiripojana, Navadol [The Joint Graduate School of Energy and Environment, King Mongkut' s University of Technology Thonburi (Thailand); Croiset, Eric [Department of Chemical Engineering, University of Waterloo (Canada)

    2010-10-15

    Thermodynamic analysis of hydrogen production from glycerol under thermal neutral conditions is studied in this work. Heat requirement from the process can be achieved from the exothermic reaction of glycerol with oxygen in air fed to the system. Two modes of operation for air feeding are considered including (i) Single-feed mode in which air is fed in combination with water and glycerol to the reformer, and (ii) Split-feed mode in which air and part of glycerol is fed to a combustor in order to generate heat. The thermal neutral conditions are considered for two levels including Reformer and System levels. It was found that the H{sub 2} yield from both modes is not significantly different at the Reformer level. In contrast, the difference becomes more pronounced at the System level. Single-feed and Split-feed modes offer high H{sub 2} yield in low (600-900 K) and high (900-1200 K) temperature ranges, respectively. The maximum H{sub 2} yields are 5.67 (water to glycerol ratio, WGR = 12, oxygen to glycerol ratio, OGR = 0.37, T = 900 K, Split-feed mode), and 3.28 (WGR = 3, OGR = 1.40, T = 900 K, Single-feed mode), for the Reformer and System levels, respectively. The difference between H{sub 2} yields in both levels mainly arises from the huge heat demand for preheating feeds in the System level, and therefore, a higher amount of air is needed to achieve the thermal neutral condition. Split-feed mode is a favorable choice in term of H{sub 2} purity because the gas product is not diluted with N{sub 2} from the air. The use of pure O{sub 2} and afterburner products (ABP) stream were also considered at the System level. The maximum H{sub 2} yield becomes 3.75 (WGR = 5.21, OGR = 1.28, T = 900 K, Split-feed mode) at thermal neutral condition when utilizing heat from the ABP stream. Finally comparisons between the different modes and levels are addressed in terms of yield of by-products, and carbon formation. (author)

  12. Chitosan-glycerol phosphate/blood implants improve hyaline cartilage repair in ovine microfracture defects.

    Science.gov (United States)

    Hoemann, Caroline D; Hurtig, Mark; Rossomacha, Evgeny; Sun, Jun; Chevrier, Anik; Shive, Matthew S; Buschmann, Michael D

    2005-12-01

    Microfracture is a surgical procedure that is used to treat focal articular cartilage defects. Although joint function improves following microfracture, the procedure elicits incomplete repair. As blood clot formation in the microfracture defect is an essential initiating event in microfracture therapy, we hypothesized that the repair would be improved if the microfracture defect were filled with a blood clot that was stabilized by the incorporation of a thrombogenic and adhesive polymer, specifically, chitosan. The objectives of the present study were to evaluate (1) blood clot adhesion in fresh microfracture defects and (2) the quality of the repair, at six months postoperatively, of microfracture defects that had been treated with or without chitosan-glycerol phosphate/blood clot implants, using a sheep model. In eighteen sheep, two 1-cm2 full-thickness chondral defects were created in the distal part of the femur and treated with microfracture; one defect was made in the medial femoral condyle, and the other defect was made in the trochlea. In four sheep, microfracture defects were created bilaterally; the microfracture defects in one knee received no further treatment, and the microfracture defects in the contralateral knee were filled with chitosan-glycerol phosphate/autologous whole blood and the implants were allowed to solidify. Fresh defects in these four sheep were collected at one hour postoperatively to compare the retention of the chitosan-glycerol phosphate/blood clot with that of the normal clot and to define the histologic characteristics of these fresh defects. In the other fourteen sheep, microfracture defects were made in only one knee and either were left untreated (control group; six sheep) or were treated with chitosan-glycerol phosphate/blood implant (treatment group; eight sheep), and the quality of repair was assessed histologically, histomorphometrically, and biochemically at six months postoperatively. In the defects that were examined

  13. Biomechanical assays amniotic membrane preserved in glycerol correlating with optical coherence tomography (OCT) and thermal gravimetric analysis (TG)

    International Nuclear Information System (INIS)

    Soares, Fernando Augusto N.; Santin, Stefany P.; Martino Junior, Antonio C.; Machado, Luci Diva B.; Freitas, Anderson Z.; Mathor, Monica B.

    2013-01-01

    Amnion or amniotic membranes (AM) are interchangeable terms used in the literature being internal part of the fetal membranes, non-vascular and multicellular tissue. The amnion has been widely used as a graft ophthalmic surgical as well as carrier substrate stem cell tissue equivalent for ocular surface reconstruction. The AM reduces scar formation and inflammation on the ocular surface, promotes epithelization also been used as a biological bandage covering the wound or burns, reducing dehydration and allowing regeneration of these areas. The amnion has usually 0.02 to 0.5 mm thick and consists of five subsequent layers: epithelium, basement membrane, compact layer, fibroblast layer and spongy layer. The mechanical strength from the membrane structure as well as the elasticity are factors attractive to the use of amnion as a surgical graft. Higher levels of rigidity and strength may improve the graft resistance necessary to resist the stress induced during growth of the new tissue formed. The amniotic membrane is obtained at elective caesarean section and subsequently, under sterile conditions, sectioned and separated from chorion and placenta, and free blood clots. The serological tests are done at the time of collection of tissue and 6 months after delivery to confirm the results. There are different methods for storing MA in tissue banks as fresh, high concentrations of glycerol, among others. The use of fresh membrane has some limitations due to the need to rapid use and high risk of contamination, however the amniotic membrane in glycerol has antiviral and antibacterial property which is dependent on the concentration, time and temperature. The AM used in transplants must be sterile to prevent the transmission of any disease. Although sterilization by radiation is an effective procedure, it can interfere on the membrane structure. Thus, verification of potential changes caused by ionizing radiation in amnion was made using the tensile test by calculating the

  14. Biomechanical assays amniotic membrane preserved in glycerol correlating with optical coherence tomography (OCT) and thermal gravimetric analysis (TG)

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Fernando Augusto N.; Santin, Stefany P.; Martino Junior, Antonio C.; Machado, Luci Diva B.; Freitas, Anderson Z.; Mathor, Monica B., E-mail: fernandonevessoares@yahoo.com.br [Instituto de Pesquisas Energetias Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Amnion or amniotic membranes (AM) are interchangeable terms used in the literature being internal part of the fetal membranes, non-vascular and multicellular tissue. The amnion has been widely used as a graft ophthalmic surgical as well as carrier substrate stem cell tissue equivalent for ocular surface reconstruction. The AM reduces scar formation and inflammation on the ocular surface, promotes epithelization also been used as a biological bandage covering the wound or burns, reducing dehydration and allowing regeneration of these areas. The amnion has usually 0.02 to 0.5 mm thick and consists of five subsequent layers: epithelium, basement membrane, compact layer, fibroblast layer and spongy layer. The mechanical strength from the membrane structure as well as the elasticity are factors attractive to the use of amnion as a surgical graft. Higher levels of rigidity and strength may improve the graft resistance necessary to resist the stress induced during growth of the new tissue formed. The amniotic membrane is obtained at elective caesarean section and subsequently, under sterile conditions, sectioned and separated from chorion and placenta, and free blood clots. The serological tests are done at the time of collection of tissue and 6 months after delivery to confirm the results. There are different methods for storing MA in tissue banks as fresh, high concentrations of glycerol, among others. The use of fresh membrane has some limitations due to the need to rapid use and high risk of contamination, however the amniotic membrane in glycerol has antiviral and antibacterial property which is dependent on the concentration, time and temperature. The AM used in transplants must be sterile to prevent the transmission of any disease. Although sterilization by radiation is an effective procedure, it can interfere on the membrane structure. Thus, verification of potential changes caused by ionizing radiation in amnion was made using the tensile test by calculating the

  15. Poly(glycerol adipate)-fatty acid esters as versatile nanocarriers

    DEFF Research Database (Denmark)

    Weiss, Verena M; Naolou, Toufik; Hause, Gerd

    2012-01-01

    Poly(glycerol adipate) (PGA) is a biodegradable polymer with promising features for nanoparticulate drug carrier systems. By acylation of PGA with fatty acids, composite systems with amphiphilic properties can be obtained. Variation of the fatty acid (laurate, stearate and behenate) and their sub...... and the nanoparticles. With their diverse particle shapes and internal structures as well as their different thermal behavior, aggregate states and polarities, the systems offer promising possibilities as delivery systems for lipophilic, amphiphilic and water soluble drugs.......Poly(glycerol adipate) (PGA) is a biodegradable polymer with promising features for nanoparticulate drug carrier systems. By acylation of PGA with fatty acids, composite systems with amphiphilic properties can be obtained. Variation of the fatty acid (laurate, stearate and behenate...

  16. 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.

  17. A Biodegradable Thermoset Polymer Made by Esterification of Citric Acid and Glycerol

    Science.gov (United States)

    Halpern, Jeffrey M.; Urbanski, Richard; Weinstock, Allison K.; Iwig, David F.; Mathers, Robert T.; von Recum, Horst

    2014-01-01

    A new biomaterial, a degradable thermoset polymer, was made from simple, economical, biocompatable monomers without the need for a catalyst. Glycerol and citric acid, non-toxic and renewable reagents, were crosslinked by a melt polymerization reaction at temperatures from 90-150°C. Consistent with a condensation reaction, water was determined to be the primary byproduct. The amount of crosslinking was controlled by the reaction conditions, including temperature, reaction time, and ratio between glycerol and citric acid. Also, the amount of crosslinking was inversely proportional to the rate of degradation. As a proof-of-principle for drug delivery applications, gentamicin, an antibiotic, was incorporated into the polymer with preliminary evaluations of antimicrobial activity. The polymers incorporating gentamicin had significantly better bacteria clearing of Staphylococcus aureus compared to non-gentamicin gels for up to nine days. PMID:23737239

  18. Crude glycerol from biodiesel industry as substrate for biosurfactant production by Bacillus subtilis ATCC 6633

    Directory of Open Access Journals (Sweden)

    Marylane de Sousa

    2014-04-01

    Full Text Available Glycerol, a co-product of the biodiesel industry, may be a suitable raw material for the production of high added-value compounds by the microorganisms. This study aimed to use the glycerol obtained from the biodiesel production process as the main carbon source for biosurfactant production by Bacillus subtilis ATCC 6633. Results indicated that the strain lowered the surface tension of the cell-free fermented broth to 31.5 ± 1.6 mN/m, indicating the production of biosurfactant. The critical micelle concentration (CMC = 33.6 mN/m obtained was similar to the previously reported for biossurfactants isolated from other Bacillus. The produced biosurfactant was able to emulsify n-hexadecane and soybean oil.

  19. Glycerol etherification with TBA: high yield to poly-ethers using a membrane assisted batch reactor.

    Science.gov (United States)

    Cannilla, Catia; Bonura, Giuseppe; Frusteri, Leone; Frusteri, Francesco

    2014-05-20

    In this work, a novel approach to obtain high yield to poly-tert-butylglycerolethers by glycerol etherification reaction with tert-butyl alcohol (TBA) is proposed. The limit of this reaction is the production of poly-ethers, which inhibits the formation of poly-ethers potentially usable in the blend with conventional diesel for transportation. The results herein reported demonstrate that the use of a water permselective membrane offers the possibility to shift the equilibrium toward the formation of poly-ethers since the water formed during reaction is continuously and selectively removed from the reaction medium by the recirculation of the gas phase. Using a proper catalyst and optimizing the reaction conditions, in a single experiment, a total glycerol conversion can be reached with a yield to poly-ethers close to 70%, which represents data never before reached using TBA as reactant. The approach here proposed could open up new opportunities for all catalytic reactions affected by water formation.

  20. Oxidative dehydration of glycerol to acrylic acid over vanadium-impregnated zeolite beta

    Energy Technology Data Exchange (ETDEWEB)

    Pestana, Carolina F.M.; Guerra, Antonio C.O.; Turci, Cassia C. [Universidade Federal do Rio de Janeiro, RJ (Brazil). Inst. de Quimica; Ferreira, Glaucio B. [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Inst. de Quimica; Mota, Claudio J.A., E-mail: cmota@iq.ufrj.br [INCT Energia e Ambiente, Universidade Federal do Rio de Janeiro, RJ (Brazil)

    2013-01-15

    The oxidative dehydration of glycerol to acrylic acid was studied over vanadium-impregnated zeolite Beta. Catalysts were prepared by wet impregnation of ammonium metavanadate over ammonium-exchanged zeolite Beta, followed by air calcination at 823 K. Impregnation reduced the specific surface area, but did not significantly affected the acidity (Bronsted and Lewis) of the zeolites. The catalytic evaluation was carried out in a fixed bed flow reactor using air as the carrier and injecting glycerol by means of a syringe pump. Acrolein was the main product, with acetaldehyde and hydroxy-acetone (acetol) being also formed. Acrylic acid was formed with approximately 25% selectivity at 548 K over the impregnated zeolites. The result can be explained by XPS (X-ray photoelectron spectroscopy) measurements, which indicated a good dispersion of the vanadium inside the pores. (author)

  1. Data on glycerol/tartaric acid-based copolymer containing ciprofloxacin for wound healing applications

    Directory of Open Access Journals (Sweden)

    E. De Giglio

    2016-06-01

    Full Text Available This data article is related to our recently published research paper “Exploiting a new glycerol-based copolymer as a route to wound healing: synthesis, characterization and biocompatibility assessment", De Giglio et al. (Colloids and Surfaces B: Biointerfaces 136 (2015 600–611 [1]. The latter described a new copolymer derived from glycerol and tartaric acid (PGT. Herein, an investigation about the PGT-ciprofloxacin (CIP interactions by means of Fourier Transform Infrared Spectroscopy (FT-IR acquired in Attenuated Total Reflectance (ATR mode and Differential Scanning Calorimetry (DSC was reported. Moreover, CIP release experiments on CIP-PGT patches were performed by High Performance Liquid Chromatography (HPLC at different pH values.

  2. Chemical characterization of composites developed from glycerol and dicarboxylic acids rein forced with piassava fiber

    International Nuclear Information System (INIS)

    Miranda, Cleidiene S.; Oliveira, Jamerson C.; Guimaraes, Danilo H.; Jose, Nadia M.; Carvalho, Ricardo F.

    2011-01-01

    In search of alternative technologies that enable the use of products with lower environmental impact, This study aims to develop a composite polymer-based piassava fiber. The sludge, waste and byproduct of commercial uses currently being used as reinforcement in polymer matrices, due to presence of lignocellulosic materials. The matrix polymer used was synthesized from glycerol with dicarboxylic acids, in order to open future perspectives on the use of glycerin generated from purified biodiesel production plastics. Composites with 2, 5, 10 wt% of piassava fiber cut into 5 mm raw and treated were obtained a mixture of solution. The materials were characterized by TGA, DSC, XRD and SEM. It was observed that the material under study is promising for the industrial market, because it has good compatibility with natural fibers allowing wider application of fiber natural and glycerol, producing semicrystalline composites and with good thermal properties. (author)

  3. Oxidative dehydration of glycerol to acrylic acid over vanadium-impregnated zeolite beta

    International Nuclear Information System (INIS)

    Pestana, Carolina F.M.; Guerra, Antonio C.O.; Turci, Cassia C.

    2013-01-01

    The oxidative dehydration of glycerol to acrylic acid was studied over vanadium-impregnated zeolite Beta. Catalysts were prepared by wet impregnation of ammonium metavanadate over ammonium-exchanged zeolite Beta, followed by air calcination at 823 K. Impregnation reduced the specific surface area, but did not significantly affected the acidity (Bronsted and Lewis) of the zeolites. The catalytic evaluation was carried out in a fixed bed flow reactor using air as the carrier and injecting glycerol by means of a syringe pump. Acrolein was the main product, with acetaldehyde and hydroxy-acetone (acetol) being also formed. Acrylic acid was formed with approximately 25% selectivity at 548 K over the impregnated zeolites. The result can be explained by XPS (X-ray photoelectron spectroscopy) measurements, which indicated a good dispersion of the vanadium inside the pores. (author)

  4. Effect of nitrogen regime on microalgal lipid production during mixotrophic growth with glycerol.

    Science.gov (United States)

    Paranjape, Kiran; Leite, Gustavo B; Hallenbeck, Patrick C

    2016-08-01

    Mixotrophic growth of microalgae to boost lipid production is currently under active investigation. Such a process could be of practical importance if a cheap source of organic carbon, such as waste glycerol from biodiesel production, could be used. Several previous studies have already demonstrated that this carbon source can be used by different indigenous strains of microalgae. In this study it is shown that different nitrogen limitation strategies can be applied to further increase lipid production during growth with glycerol. In one strategy, cultures were grown in nitrogen replete medium and then resuspended in nitrogen free medium. In a second strategy, cultures were grown with different initial concentrations of nitrate. Lipid production by the two microalgal strains used, Chlorella sorokiniana (PCH02) and Chlorella vulgaris (PCH05), was shown to be boosted by strategies of nitrogen limitation, but they responded differently to how nitrogen limitation was imposed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Electrochemical method for producing a biodiesel mixture comprising fatty acid alkyl esters and glycerol

    Science.gov (United States)

    Lin, YuPo J; St. Martin, Edward J

    2013-08-13

    The present invention relates to an integrated method and system for the simultaneous production of biodiesel from free fatty acids (via esterification) and from triglycerides (via transesterification) within the same reaction chamber. More specifically, one preferred embodiment of the invention relates to a method and system for the production of biodiesel using an electrodeionization stack, wherein an ion exchange resin matrix acts as a heterogeneous catalyst for simultaneous esterification and transesterification reactions between a feedstock and a lower alcohol to produce biodiesel, wherein the feedstock contains significant levels of free fatty acid. In addition, because of the use of a heterogeneous catalyst, the glycerol and biodiesel have much lower salt concentrations than raw biodiesel produced by conventional transesterification processes. The present invention makes it much easier to purify glycerol and biodiesel.

  6. Selective Hydrogenolysis of Glycerol and Crude Glycerol (a By-Product or Waste Stream from the Biodiesel Industry to 1,2-Propanediol over B2O3 Promoted Cu/Al2O3 Catalysts

    Directory of Open Access Journals (Sweden)

    Malaya R. Nanda

    2017-06-01

    Full Text Available The performance of boron oxide (B2O3-promoted Cu/Al2O3 catalyst in the selective hydrogenolysis of glycerol and crude glycerol (a by-product or waste stream from the biodiesel industry to produce 1,2-propanediol (1,2-PDO was investigated. The catalysts were characterized using N2-adsorption-desorption isotherm, Inductively coupled plasma atomic emission spectroscopy (ICP-AES, X-ray diffraction (XRD, ammonia temperature programmed desorption (NH3-TPD, thermogravimetric analysis (TGA, temperature programmed reduction (TPR, and transmission electron microscopy (TEM. Incorporation of B2O3 to Cu/Al2O3 was found to enhance the catalytic activity. At the optimum condition (250 °C, 6 MPa H2 pressure, 0.1 h−1 WHSV (weight hourly space velocity, and 5Cu-B/Al2O3 catalyst, 10 wt% aqueous solution of glycerol was converted into 1,2-PDO at 98 ± 2% glycerol conversion and 98 ± 2% selectivity. The effects of temperature, pressure, boron addition amount, and liquid hourly space velocity were studied. Different grades of glycerol (pharmaceutical, technical, or crude glycerol were used in the process to investigate the stability and resistance to deactivation of the selected 5Cu-B/Al2O3 catalyst.

  7. Ammonia control in children with urea cycle disorders (UCDs); Phase 2 comparison of sodium phenylbutyrate and glycerol phenylbutyrate☆

    OpenAIRE

    Lichter-Konecki, Uta; Diaz, G.A.; Merritt, J.L.; Feigenbaum, A.; Jomphe, C.; Marier, J.F.; Beliveau, M.; Mauney, J.; Dickinson, K.; Martinez, A.; Mokhtarani, M.; Scharschmidt, B.; Rhead, W.

    2011-01-01

    Twenty four hour ammonia profiles and correlates of drug effect were examined in a phase 2 comparison of sodium phenylbutyrate (NaPBA) and glycerol phenylbutyrate (GPB or HPN-100), an investigational drug being developed for urea cycle disorders (UCDs).

  8. Ethylene glycol, but not DMSO, could replace glycerol inclusion in soybean lecithin-based extenders in ram sperm cryopreservation.

    Science.gov (United States)

    Najafi, Abouzar; Daghigh-Kia, Hossein; Dodaran, Hossein Vaseghi; Mehdipour, Mahdieh; Alvarez-Rodriguez, Manuel

    2017-02-01

    The aim of this study was to evaluate the effects of glycerol, ethylene glycol or DMSO in a soybean lecithin extender for freezing ram semen. In this study, 20 ejaculates were collected from four Ghezel rams and diluted with soybean lecithin extender with glycerol (7%), ethylene glycol (3%, 5% and 7%) or DMSO (3%, 5% and 7%). Sperm motility (CASA), membrane integrity (HOS test), viability, total abnormality, mitochondrial activity (Rhodamine 123) and apoptotic features (Annexin V/Propidium iodide) were assessed after thawing. There was no significant difference between glycerol and ethylene glycol at different concentrations (3% and 5%) regarding sperm total and progressive motility, viability, and membrane integrity. The least percentages of mitochondrial functionality were observed in samples frozen with all different DMSO concentrations tested (Plecithin extender. We propose that glycerol in a soybean lecithin based extender could be replaced by ethylene glycol at 3% or 5% concentrations. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Seasonal shifts in accumulation of glycerol biosynthetic gene transcripts in mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae, larvae

    Directory of Open Access Journals (Sweden)

    Jordie D. Fraser

    2017-06-01

    Full Text Available Winter mortality is a major factor regulating population size of the mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae. Glycerol is the major cryoprotectant in this freeze intolerant insect. We report findings from a gene expression study on an overwintering mountain pine beetle population over the course of 35 weeks. mRNA transcript levels suggest glycerol production in the mountain pine beetle occurs through glycogenolytic, gluconeogenic and potentially glyceroneogenic pathways, but not from metabolism of lipids. A two-week lag period between fall glycogen phosphorylase transcript and phosphoenolpyruvate carboxykinase transcript up-regulation suggests that gluconeogenesis serves as a secondary glycerol-production process, subsequent to exhaustion of the primary glycogenolytic source. These results provide a first look at the details of seasonal gene expression related to the production of glycerol in the mountain pine beetle.

  10. Improved glycerol production from cane molasses by the sulfite process with vacuum or continuous carbon dioxide sparging during fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Kalle, G.P.; Naik, S.C.; Lashkari, B.Z.

    1985-01-01

    The conventional sulfite process for glycerol production from molasses using Saccharomyces cerevisiae var. Hansen was modified to obtain product concentrations of up to 230 g/l and productivity of 15 g/l.d by fermenting under vacuum (80 mm) or with continuous sparging of CO2 (0.4 vvm). Under these conditions the requirement of sulfite for optimum production of glycerol was reduced by two thirds (20 g/l), the ethanol concentration in the medium was kept below 30 g/l and the competence of yeast cells to ferment was conserved throughout the fermentation period for up to 20 days. In addition to the above, the rate of incorporation of sulfite had a significant effect on glucose fermentation and glycerol yields. There was an optimal relationship between glycerol yields and the molar ratio of sulfite to glucose consumed, which for cane molasses was 0.67. This ratio was characteristic of the medium composition.

  11. Technological processes for obtaining ß-carotene and glycerol from Dunaliella sp. at 'Las Cumaraguas' Saltworks

    International Nuclear Information System (INIS)

    Acacio-ChirinoI, Noel José; Zumalacárregui-de Cárdenas, Lourdes Margarita

    2017-01-01

    Technological processes were developed for ß-carotene and glycerol extraction from Dunaliella sp. at 'Las Cumaraguas' Saltworks. Dunaliella sp. microalgae was characterize. It was established the technological flow of the process from laboratory data; energy balances and necessary energetic calculations were done, in order to select and size the required equipment for a pilot plant scale to produce one ton of ß-carotene. Two possibilities were evaluated: extraction with organic solvents and extraction with supercritical fluids. The procedure showed that ß-carotene and glycerol extractions are possible by means of the presented technological diagram, with 15,4 % of biomass ß-carotene yield and 5 % of biomass glycerol yield, for a conventional extraction and a yield of 70 % for ß-carotene from pigments and 5 % of biomass glycerol yield, for extraction with supercritical fluid. (author)

  12. Radioprotective action of glycerol and cysteamine on inactivation and mutagenesis in Salmonella tester strains after gamma and heavy ion irradiation

    International Nuclear Information System (INIS)

    Basha, S.G.; Krasavin, E.A.; Kozubek, S.

    1991-01-01

    Inactivation and mutagenesis were studied in Salmonella tester strains after γ-irradiation and after heavy ion irradiation in the presence of glycerol and cysteamine. Bacterial cells were irradiated at Dubna, JINR. Ions from deuterons to carbon were used with residual energies 2-9 MeV/u. The protective effect of glycerol was found both for γ-radiation and for heavy ions up to 50 keV/μm for both cell inactivation and mutagenesis in Salmonella tester strains with different mutation events. Cell sensitivity slightly increased with LET before falling down. The maximum was shifted in the presence of glycerol to the left and was less pronounced. The radioprotective effect of glycerol diminished gradually with LET from 2.0 for γ-radiation to 1.1 for carbon ions. Mutagenesis increases with LET in TA100 strain; in TA98 strain no marked increase could be detected. 13 refs.; 4 figs.; 5 tabs

  13. Validated ¹H and 13C Nuclear Magnetic Resonance Methods for the Quantitative Determination of Glycerol in Drug Injections.

    Science.gov (United States)

    Lu, Jiaxi; Wang, Pengli; Wang, Qiuying; Wang, Yanan; Jiang, Miaomiao

    2018-05-15

    In the current study, we employed high-resolution proton and carbon nuclear magnetic resonance spectroscopy (¹H and 13 C NMR) for quantitative analysis of glycerol in drug injections without any complex pre-treatment or derivatization on samples. The established methods were validated with good specificity, linearity, accuracy, precision, stability, and repeatability. Our results revealed that the contents of glycerol were convenient to calculate directly via the integration ratios of peak areas with an internal standard in ¹H NMR spectra, while the integration of peak heights were proper for 13 C NMR in combination with an external calibration of glycerol. The developed methods were both successfully applied in drug injections. Quantitative NMR methods showed an extensive prospect for glycerol determination in various liquid samples.

  14. Effects of Locally Applied Glycerol and Xylitol on the Hydration, Barrier Function and Morphological Parameters of the Skin.

    Science.gov (United States)

    Korponyai, Csilla; Szél, Edit; Behány, Zoltán; Varga, Erika; Mohos, Gábor; Dura, Ágnes; Dikstein, Shabtay; Kemény, Lajos; Erős, Gábor

    2017-02-08

    Glycerol and xylitol hydrate the skin and improve its barrier function over a short period. We studied the effects of glycerol and xylitol on the physiological properties and morphology of the skin after longer-term application. Twelve volunteers with dry skin were examined. Three areas on the arms were determined. Area 1 served as untreated control. The vehicle was applied to area 2, while area 3 was treated twice daily with a formulation containing glycerol (5%) and xylitol (5%) for 14 days. Transepidermal water loss (TEWL), hydration and biomechanical properties of the skin were monitored. Biopsies were taken for routine histology and immunohistochemistry for filaggrin and matrix metalloproteinase-1 (MMP-1). The polyols increased the skin hydration and protein quantity of filaggrin, elevated the interdigitation index, decreased the TEWL and improved the biomechanical properties of the skin, but did not change the protein expression of MMP-1. A combination of glycerol and xylitol can be useful additional therapy for dry skin.

  15. A comparative study on glycerol metabolism to erythritol and citric acid in Yarrowia lipolytica yeast cells.

    Science.gov (United States)

    Tomaszewska, Ludwika; Rakicka, Magdalena; Rymowicz, Waldemar; Rywińska, Anita

    2014-09-01

    Citric acid and erythritol biosynthesis from pure and crude glycerol by three acetate-negative mutants of Yarrowia lipolytica yeast was investigated in batch cultures in a wide pH range (3.0-6.5). Citric acid biosynthesis was the most effective at pH 5.0-5.5 in the case of Wratislavia 1.31 and Wratislavia AWG7. With a decreasing pH value, the direction of biosynthesis changed into erythritol synthesis accompanied by low production of citric acid. Pathways of glycerol conversion into erythritol and citric acid were investigated in Wratislavia K1 cells. Enzymatic activity was compared in cultures run at pH 3.0 and 4.5, that is, under conditions promoting the production of erythritol and citric acid, respectively. The effect of pH value (3.0 and 4.5) and NaCl presence on the extracellular production and intracellular accumulation of citric acid and erythritol was compared as well. Low pH and NaCl resulted in diminished activity of glycerol kinase, whereas such conditions stimulated the activity of glycerol-3-phosphate dehydrogenase. The presence of NaCl strongly influenced enzymes activity - the effective erythritol production was correlated with a high activity of transketolase and erythrose reductase. Therefore, presented results confirmed that transketolase and erythrose reductase are involved in the overproduction of erythritol in the cells of Y. lipolytica yeast. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  16. 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

  17. Skin-specific regulation of SREBP processing and lipid biosynthesis by glycerol kinase 5

    OpenAIRE

    Zhang, Duanwu; Tomisato, Wataru; Su, Lijing; Sun, Lei; Choi, Jin Huk; Zhang, Zhao; Wang, Kuan-wen; Zhan, Xiaoming; Choi, Mihwa; Li, Xiaohong; Tang, Miao; Castro-Perez, Jose M.; Hildebrand, Sara; Murray, Anne R.; Moresco, Eva Marie Y.

    2017-01-01

    We discovered a previously unrecognized regulator of cholesterol biosynthesis, glycerol kinase 5 (GK5), which functions exclusively in the skin independently of cholesterol regulation in other tissues. GK5 negatively regulates the processing and nuclear localization of sterol regulatory element binding proteins, transcription factors that control expression of virtually all cholesterol synthesis enzymes. Excessive amounts of cholesterol, triglycerides, and ceramides were found in the skin of ...

  18. Evaluation of additive effects of hydrolyzed jojoba (Simmondsia chinensis) esters and glycerol: a preliminary study.

    Science.gov (United States)

    Meyer, Jaimi; Marshall, Brooke; Gacula, Maximo; Rheins, Lawrence

    2008-12-01

    Glycerol has long served the topical prescriptive and personal care industry as a versatile and functional active and inactive ingredient. In skin care products, it acts primarily as an emollient, softening the skin through robust humectant hydration action. Hydrolyzed Jojoba Esters K-20W (K-20W) have been shown to increase skin hydration and improve sensory skin "feel" when included in a variety of skin, hair, and nail care cosmetic/personal care formulations. The addition of glycerol and hydrolyzed jojoba esters provides a substantial long-acting 24 h (moisturizing) skin hydration effect for topical products. A small pilot study was conducted to support the "proof of concept" that an enhanced, additive role exists between these two ingredients resulting in a long-term (24 h) skin moisturization effect. Topical treatments were applied to the skin (lower leg) of subjects, and evaluations were made at baseline and 8- to 24-h post-application. Skin hydration data were obtained via bio-instrumental transepidermal water loss (TEWL) measurements and expert clinical skin grading, including standardized digital clinical photography. Clinical skin grading evaluations and TEWL measurements found that significantly lower evaporative (P jojoba esters) than with glycerol alone in a standard base skin care lotion at 8 and 24 h posttreatment. This preliminary data "proof of concept" supports the position that glycerol and hydrolyzed jojoba esters work in tandem to enhance skin moisturization for at least 24 h. This unique moisturizing potential may prove valuable in the future development of cosmetic and over-the-counter/prescriptive topical products, including new medicaments containing botanicals. This fact is further reinforced with the recent greater commercial use and demand for defined safe botanicals in cosmetic as well as pharmaceutical topical formulations. Additional mechanistic studies are underway.

  19. 1,3-Propanediol production from crude glycerol by Clostridium butyricum DSP1 in repeated batch

    Directory of Open Access Journals (Sweden)

    Daria Szymanowska-Powałowska

    2014-11-01

    Conclusions: The experiments proved that by using a portion of metabolically active biomass as inoculum for another fermentation formula it is possible to eliminate the stage of inoculum growth and thereby reduce the length of the whole operation. Additionally, that strategy avoids the phase of microbial adaptation to a different source of carbon such as crude glycerol, which is more difficult to utilize, thus improving the kinetic parameters of 1,3-PD production.

  20. ETHANOL DEHYDRATION IN PACKED DISTILLATION COLUMN USING GLYCEROL AS ENTRAINER: EXPERIMENTS AND HETP EVALUATION

    OpenAIRE

    Souza,W. L. R.; Silva,C. S.; Meleiro,L. A. C.; Mendes,M. F.

    2016-01-01

    Abstract The ethanol-water separation is very important because ethanol is widely applied in the chemical industry and its use as a fuel can reduce the pollution emitted to the air. However, anhydrous ethanol production using conventional distillation is impossible, at atmospheric pressure, due to the presence of an azeotrope. In the present work, experimental tests were carried out in order to evaluate the use of glycerol as an entrainer, in substitution of ethylene glycol in an extractive d...

  1. Microwave-assisted and carbonaceous catalytic pyrolysis of crude glycerol from biodiesel waste for energy production

    International Nuclear Information System (INIS)

    Ng, Jo-Han; Leong, Swee Kim; Lam, Su Shiung; Ani, Farid Nasir; Chong, Cheng Tung

    2017-01-01

    Highlights: • Crude glycerol is pyrolysed catalytically via microwave irradiation to produce bioenergy. • Carbonaceous catalyst elevates pyrolysis temperature and promotes selectivity towards H_2 production. • Synthesis gas consisting of mainly H_2 and CH_4 was predominantly produced at long residence time and high temperature. • Production of bio-oil consisting of oxygenated compounds peaks at intermediate carrier gas flow rate. • Energy profit analysis shows positive energy gained with increasing residence time and decreasing reaction temperature. - Abstract: Biodiesel proliferation as a sustainable fuel has led to a glut of crude glycerol as co-product. This scenario made a previously lucrative co-product in the food and pharmaceutical sectors into a bioresource waste. The present study investigates the utilisation of a microwave-assisted pyrolysis technique to convert crude glycerol from biodiesel waste into usable bioenergy source. Operating conditions ranged from a temperature of 300–800 °C at carrier gas flow rates of 100–2000 mL/min, with the effects of carbonaceous catalyst on the selectivity of reaction pathway being investigated. Within the aforementioned conditions, the proportion of products phases is mainly dependent on the residence time inside the quartz reactor, followed by the reaction temperature. This is due to the combined factors of the reaction sequence and provision of activation energy to change product phases. The third factor of carbonaceous catalyst shows a predisposition towards hydrogen gas selectivity, leading to a lower overall gaseous product mass when factoring in products from all phases. An analysis of the energy content revealed that overall energy profit increases with decreasing temperature and increasing residence time. This concurs with solid energy content increasing in the same conditions, while it increases for liquid and gaseous products with decreasing temperature and flow rate, respectively. The

  2. Production and characterization of polyhydroxybutyrate from Vibrio harveyi MCCB 284 utilizing glycerol as carbon source.

    Science.gov (United States)

    Mohandas, S P; Balan, L; Lekshmi, N; Cubelio, S S; Philip, R; Bright Singh, I S

    2017-03-01

    Production and characterization of polyhydroxybutyrate (PHB) from moderately halophilic bacterium Vibrio harveyi MCCB 284 isolated from tunicate Phallusia nigra. Twenty-five bacterial isolates were obtained from tunicate samples and three among them exhibited an orange fluorescence in Nile red staining indicating the presence of PHB. One of the isolates, MCCB 284, which showed rapid growth and good polymer yield, was identified as V. harveyi. The optimum conditions of the isolate for the PHB production were pH 8·0, sodium chloride concentration 20 g l -1 , inoculum size 0·5% (v/v), glycerol 20 g l -1 and 72 h of incubation at 30°C. Cell dry weight (CDW) of 3·2 g l -1 , PHB content of 2·3 g l -1 and final PHB yield of 1·2 g l -1 were achieved. The extracted PHB was characterized by FTIR, NMR and DSC-TGA techniques. An isolate of V. harveyi that could effectively utilize glycerol for growth and PHB accumulation was obtained from tunicate P. nigra. PHB produced was up to 72% based on CDW. This is the first report of an isolate of V. harveyi which utilizes glycerol as the sole carbon source for PHB production with high biomass yield. This isolate could be of use as candidate species for commercial PHB production using glycerol as the feed stock or as source of genes for recombinant PHB production or for synthetic biology. © 2016 The Society for Applied Microbiology.

  3. ROS generation and multiple forms of mammalian mitochondrial glycerol-3-phosphate dehydrogenase

    Czech Academy of Sciences Publication Activity Database

    Mráček, Tomáš; Holzerová, Eliška; Drahota, Zdeněk; Kovářová, Nikola; Vrbacký, Marek; Ješina, Pavel; Houštěk, Josef

    2014-01-01

    Roč. 1837, č. 1 (2014), s. 98-111 ISSN 0005-2728 R&D Projects: GA ČR(CZ) GPP303/10/P227; GA MŠk(CZ) LL1204 Grant - others:Univerzita Karlova(CZ) 750213 Institutional support: RVO:67985823 Keywords : mitochondrial glycerol-3-phosphate dehydrogenase * ROS production * supercomplex * in-gel ROS detection Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.353, year: 2014

  4. Silicon-zinc-glycerol hydrogel, a potential immunotropic agent for topical application.

    Science.gov (United States)

    Khonina, Tat'yana G; Ivanenko, Maria V; Chupakhin, Oleg N; Safronov, Alexander P; Bogdanova, Ekaterina A; Karabanalov, Maxim S; Permikin, Vasily V; Larionov, Leonid P; Drozdova, Lyudmila I

    2017-09-30

    Nanoparticles synthesized using sol-gel method are promising agents for biomedical applications, in particular for the therapy and diagnosis of various diseases. Using silicon and zinc glycerolates as biocompatible precursors we synthesized by the sol-gel method a new bioactive silicon-zinc-containing glycerohydrogel combining the positive pharmacological properties of the precursors. In the present work the structural features of silicon-zinc-containing glycerohydrogel and its immunotropic properties were studied. The advanced physical methods, including XRD, TEM, dynamic and electrophoretic light scattering, were used for studying the structural features of the gel. Hydrolysis of zinc monoglycerolate was investigated under gelation conditions. Evaluation of the efficiency of silicon-zinc-containing glycerohydrogel in providing immune functions was carried out using a model of the complicated wound process behind immunosuppression induced by hydrocortisone administration in the Wistar rats. It has been shown that zinc monoglycerolate exists in the state of amorphous nanoparticles in the cells of 3D-network formed due to incomplete hydrolysis of silicon glycerolates and subsequent silanol condensation. Zinc monoglycerolate is not hydrolyzed and does not enter 3D-network of the gel with the formation of Zn-O-Si groups, but it forms a separate phase. Immunotropic action of silicon-zinc-containing glycerohydrogel was revealed by the histology and immunohistochemistry methods. Amorphous nanoparticles of zinc monoglycerolate, water-soluble silicon glycerolates, and products of their hydrolytic transformations, which are present in a aqueous-glycerol medium, are in the first place responsible for the pharmacological activity of hydrogel. The results obtained allow us to consider silicon-zinc-containing glycerohydrogel as a promising immunotropic agent for topical application. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Monitoring the process of purification of crude glycerol derived from biodiesel production: a method based on fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, Keurison F.; Caires, Anderson R.L. [Universidade Federal da Grande Dourados, MS (Brazil). Grupo de Optica Aplicada; Oliveira, Samuel L. [Universidade Federal de Mato Grosso do Sul (UFMS), MS (Brazil). Grupo de Optica e Fotonica

    2011-07-01

    Full text. The use of biodiesel has increased worldwide. The biodiesel production on an industrial scale has been based on the transesterification of vegetable oils and fats with methanol in the presence of an alkaline catalyst. During the transesterification, one molecule of triglyceride reacts with three molecules of alcohol to produce glycerol and molecules of alkyl esters (biodiesel). As a result, an increase in biodiesel production also enhances the availability of glycerol on the market. However, crude glycerin has about 30% of impurities which are inherent to biodiesel production such as catalyst, alcohol and fatty acids. The present study evaluated the usefulness of the fluorescence spectroscopy as a tool to monitor the glycerol purification process. Glycerol samples were obtained from transesterification of soybean, canola, and sunflower oils in the presence of NaOH. After stirring time, the solutions were let to stand in separating funnels, then two phases were observed: one containing mainly biodiesel and other consisting of glycol. Then, the respective glycerol samples were collected, henceforth called G1. After that, it was added H2SO4 (20%) in the crude glycerol samples to reduce their pH to 4 in order to remove fatty acids. The solutions were stored for 24 hours in separating funnels. The glycerol (heavy phase), hereafter named G2, was then separated and filtered. To remove other impurities from G2 samples by means of ionic exchange columns, the samples were neutralized and diluted using Milli-Q water (G3 samples). Aliquots of 20 mL were then passed through cationic and anionic resins (G4 and G5 samples, respectively). Emission and excitation spectra of the G1-G5 samples as well as of the glycerol PA-ACS (reference) were recorded at room temperature using a spectrofluorimeter. The emission spectra were obtained setting the excitation at 325nm and monitoring the emission in the 330-800nm range. Fluorimetric maps were also achieved by pumping the

  6. Composite glycerol/graphite/aromatic acid matrices for thin-layer chromatography/matrix-assisted laser desorption/ionization mass spectrometry of heterocyclic compounds.

    Science.gov (United States)

    Esparza, Cesar; Borisov, R S; Varlamov, A V; Zaikin, V G

    2016-10-28

    New composite matrices have been suggested for the analysis of mixtures of different synthetic organic compounds (N-containing heterocycles and erectile dysfunction drugs) by thin layer chromatography/matrix-assisted laser desorption ionization time-of-flight mass spectrometry (TLC/MALDI-TOF). Different mixtures of classical MALDI matrices and graphite particles dispersed in glycerol were used for the registration of MALDI mass spectra directly from TLC plates after analytes separation. In most of cases, the mass spectra possessed [M+H] + ions; however, for some analytes only [M+Na] + and [M+K] + ions were observed. These ions have been used to generate visualized TLC chromatograms. The described approach increases the desorption/ionization efficiencies of analytes separated by TLC, prevent spot blurring, simplifies and decrease time for sample preparation. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Tartronate semialdehyde reductase defines a novel rate-limiting step in assimilation and bioconversion of glycerol in Ustilago maydis.

    Directory of Open Access Journals (Sweden)

    Yanbin Liu

    Full Text Available BACKGROUND: Glycerol is a by-product of biodiesel production. Currently, it has limited applications with low bioconversion efficiency to most metabolites reported. This is partly attributed to the poor knowledge on the glycerol metabolic pathway in bacteria and fungi. METHODOLOGY/PRINCIPAL FINDINGS: We have established a fast screening method for identification of genes that improve glycerol utilization in Ustilago maydis. This was done by comparing the growth rates of T-DNA tagged mutant colonies on solid medium using glycerol as the sole carbon source. We present a detailed characterization of one of the mutants, GUM1, which contains a T-DNA element inserted into the promoter region of UM02592 locus (MIPS Ustilago maydis database, MUMDB, leading to enhanced and constitutive expression of its mRNA. We have demonstrated that um02592 encodes a functional tartronate semialdehyde reductase (Tsr1, which showed dual specificity to cofactors NAD(+ and NADP(+ and strong substrate specificity and enantioselectivity for D-glycerate. Improved glycerol assimilation in GUM1 was associated with elevated expression of tsr1 mRNA and this could be phenocopied by over-expression of the gene. Glycolipid accumulation was reduced by 45.2% in the knockout mutant whereas introduction of an extra copy of tsr1 driven by the glyceraldehyde phosphate dehydrogenase promoter increased it by 40.4%. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that tartronate semialdehyde reductase (TSR plays an important role in glycerol assimilation in U. maydis and defines a novel target in genetic engineering for improved conversion of glycerol to higher value products. Our results add significant depth to the understanding of the glycerol metabolic pathway in fungi. We have demonstrated, for the first time, a biological role of a eukaryotic TSR.

  8. Synthesis and characterization of poly(glycerol citrate/sebacate); Preparacao de caracterizacao do poli(glicerol citrato/sebacato)

    Energy Technology Data Exchange (ETDEWEB)

    Brioude, Michel M.; Guimaraes, Danilo H.; Fiuza, Raigenis P.; Boaventura, Jaime S.; Jose, Nadia M., E-mail: mbrioude@gmail.com [Universidade Federal da Bahia - UFBA, Instituto de Quimica, Salvador, BA (Brazil)

    2011-07-01

    In this work were prepared and characterized the poly(glycerol citrate/sebacate) in three different ratios between acids. The polymers were prepared by a polycondensation reaction between glycerol and citric/sebacic acids and characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning differential calorimetry (DSC), scanning electron microscopy (SEM). The results showed that the polymers are polyesters and its crystallinity, thermal and morphological properties were modified by sebacic acid adding. (author)

  9. Sustainable production of hydrogen and chemical commodities from biodiesel waste crude glycerol and cellulose by biological and catalytic processes

    OpenAIRE

    Maru, Biniam Taddele

    2013-01-01

    Hydrogen has a significant potential as clean and ‘green’ fuel of the future. Accordingly, this thesis investigated how to generate a sustainable production of hydrogen and other chemical commodities through study of: 1) Fermentative behavior of anaerobichydrogen producing microorganisms from pure glycerol and biodiesel waste crude glycerol; 2) The advantage of using a solid supportimmobilisationof microorganisms 3) The integration of the dark fermentative system with the catalytic hydrolysi...

  10. Impact of glycerol and nitrogen concentration on Enterobacter A47 growth and exopolysaccharide production.

    Science.gov (United States)

    Torres, Cristiana A V; Marques, Rodolfo; Ferreira, Ana R V; Antunes, Sílvia; Grandfils, Christian; Freitas, Filomena; Reis, Maria A M

    2014-11-01

    Enterobacter A47 produces a fucose-containing exopolysaccharide (EPS) by cultivation in mineral medium supplemented with glycerol. EPS synthesis by Enterobacter A47 was shown to be influenced by both the initial glycerol and nitrogen concentrations and by the nutrients' feeding rate during the fed-batch phase. Initial nitrogen concentrations above 1.05g/L were detrimental for EPS synthesis: the productivity was reduced to 0.35-0.62g/Ld (compared to 1.89-2.04g/Ld under lower nitrogen concentrations) and the polymer had lower fucose content (14-17%mol, compared to 36-38%mol under lower nitrogen concentrations). On the other hand, EPS productivity was improved to 5.66g/Ld by increasing the glycerol and nitrogen feeding rates during the fed-batch phase. However, the EPS thus obtained had lower fucose (26%mol) and higher galactose (34%mol) contents, as well as lower average molecular weight (7.2×10(5)). The ability of Enterobacter A47 to synthesize EPS with different physico-chemical characteristics may be useful for the generation of biopolymers with distinct functional properties suitable for different applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Biosurfactants production by yeasts using soybean oil and glycerol as low cost substrate.

    Science.gov (United States)

    Accorsini, Fábio Raphael; Mutton, Márcia Justino Rossini; Lemos, Eliana Gertrudes Macedo; Benincasa, Maria

    2012-01-01

    Biosurfactants are bioactive agents that can be produced by many different microorganisms. Among those, special attention is given to yeasts, since they can produce many types of biosurfactants in large scale, using several kinds of substrates, justifying its use for industrial production of those products. For this production to be economically viable, the use of residual carbon sources is recommended. The present study isolated yeasts from soil contaminated with petroleum oil hydrocarbons and assessed their capacity for producing biosurfactants in low cost substrates. From a microbial consortium enriched, seven yeasts were isolated, all showing potential for producing biosurfactants in soybean oil. The isolate LBPF 3, characterized as Candida antarctica, obtained the highest levels of production - with a final production of 13.86 g/L. The isolate LBPF 9, using glycerol carbon source, obtained the highest reduction in surface tension in the growth medium: approximately 43% of reduction after 24 hours of incubation. The products obtained by the isolates presented surfactant activity, which reduced water surface tension to values that varied from 34 mN/m, obtained from the product of isolates LBPF 3 and 16 LBPF 7 (respectively characterized as Candida antarctica and Candida albicans) to 43 mN/m from the isolate LPPF 9, using glycerol as substrate. The assessed isolates all showed potential for the production of biosurfactants in conventional sources of carbon as well as in agroindustrial residue, especially in glycerol.

  12. Biosurfactants production by yeasts using soybean oil and glycerol as low cost substrate

    Directory of Open Access Journals (Sweden)

    Fábio Raphael Accorsini

    2012-03-01

    Full Text Available Biosurfactants are bioactive agents that can be produced by many different microorganisms. Among those, special attention is given to yeasts, since they can produce many types of biosurfactants in large scale, using several kinds of substrates, justifying its use for industrial production of those products. For this production to be economically viable, the use of residual carbon sources is recommended. The present study isolated yeasts from soil contaminated with petroleum oil hydrocarbons and assessed their capacity for producing biosurfactants in low cost substrates. From a microbial consortium enriched, seven yeasts were isolated, all showing potential for producing biosurfactants in soybean oil. The isolate LBPF 3, characterized as Candida antarctica, obtained the highest levels of production - with a final production of 13.86 g/L. The isolate LBPF 9, using glycerol carbon source, obtained the highest reduction in surface tension in the growth medium: approximately 43% of reduction after 24 hours of incubation. The products obtained by the isolates presented surfactant activity, which reduced water surface tension to values that varied from 34 mN/m, obtained from the product of isolates LBPF 3 and 16 LBPF 7 (respectively characterized as Candida antarctica and Candida albicans to 43 mN/m from the isolate LPPF 9, using glycerol as substrate. The assessed isolates all showed potential for the production of biosurfactants in conventional sources of carbon as well as in agroindustrial residue, especially in glycerol.

  13. The effect of mixing on fermentation of primary solids, glycerol, and biodiesel waste.

    Science.gov (United States)

    Ghasemi, Marzieh; Randall, Andrew A

    2018-03-01

    In this study, the effect of mixing on volatile fatty acid (VFA) production and composition was investigated through running five identical bench-scale reactors that were filled with primary solid and dosed with either pure glycerol or biodiesel waste. Experimental results revealed that there was an inverse correlation between the mixing intensity and the VFA production. The total VFA production in the un-mixed reactor was 9,787 ± 3,601 mg COD/L, whereas in the reactor mixed at 100 rpm this dropped to 3,927 ± 1,175 mg COD/L, while both types of reactor were dosed with pure glycerol at the beginning of each cycle to reach the initial concentration of 1,000 mg/L (1,217 mg COD/L). Propionic acid was the dominant VFA in all the reactors except the reactor mixed at 30 rpm. It is hypothesized that low mixing facilitated hydrogen transfer between obligate hydrogen producing acetogens (OHPA) and hydrogen consuming acidogens in these non-methanogenic reactors. Also, in a narrower range of mixing (0 or 7 rpm), the total VFA production in biodiesel waste-fed reactors was considerably higher than that of pure glycerol-fed reactors.

  14. Producing fuel alcohol by extractive distillation: Simulating the process with glycerol

    Directory of Open Access Journals (Sweden)

    Ana María Uyazán

    2006-01-01

    Full Text Available Downstream separation processes in biotechnology form part of the stages having most impact on a product’s final cost. The tendency throughout the world today is to replace fossil fuels with those having a renewable origin such as ethanol; this, in turn, produces a demand for the same and the need for optimising fermentation, treating vinazas and dehydration processes. The present work approaches the problem of dehydration through simulating azeotropic ethanol extractive distillation using glycerol as separation agent. Simulations were done on an Aspen Plus process simulator (Aspen Tech version 11.1. The simulated process involves two distillation columns, a dehydrator and a glycerol recuperation column. Simulation restrictions were ethanol’s molar composition in dehydrator column distillate and the process’s energy consumption. The effect of molar reflux ratio, solvent-feed ratio, solvent entry and feed stage and solvent entry temperature were evaluated on the chosen restrictions. The results showed that the ethanol-water mixture dehydration with glycerol as separation agent is efficient from the energy point of view.

  15. From crude glycerol to carotenoids by using a Rhodotorula glutinis mutant.

    Science.gov (United States)

    Cutzu, Raffaela; Coi, Annalisa; Rosso, Fulvia; Bardi, Laura; Ciani, Maurizio; Budroni, Marilena; Zara, Giacomo; Zara, Severino; Mannazzu, Ilaria

    2013-06-01

    In this work eighteen red yeasts were screened for carotenoids production on glycerol containing medium. Strain C2.5t1 of Rhodotorula glutinis, that showed the highest productivity, was UV mutagenized. Mutant 400A15, that exhibited a 280 % increase in β-carotene production in respect to the parental strain, was selected. A central composite design was applied to 400A15 to optimize carotenoids and biomass productions. Regression analyses of the quadratic polynomial equations obtained (R(2) = 0.87 and 0.94, for carotenoids and biomass, respectively) suggest that the models are reliable and significant (P < 0.0001) in the prediction of carotenoids and biomass productions on the basis of the concentrations of crude glycerol, yeast extract and peptone. Accordingly, total carotenoids production achieved (14.07 ± 1.45 mg l(-1)) under optimized growth conditions was not statistically different from the maximal predicted (14.64 ± 1.57 mg l(-1)) (P < 0.05), and it was about 100 % higher than that obtained under un-optimized conditions. Therefore mutant 400A15 may represent a biocatalyst of choice for the bioconversion of crude glycerol into value-added metabolites, and a tool for the valorization of this by-product of the biodiesel industry.

  16. Optimization of catalytic glycerol steam reforming to light olefins using Cu/ZSM-5 catalyst

    International Nuclear Information System (INIS)

    Zakaria, Z.Y.; Amin, N.A.S.; Linnekoski, J.

    2014-01-01

    Highlights: • Glycerol steam reforming to light olefin using Cu/ZSM-5 process was optimized. • Response surface methodology and multi-objective genetic algorithm were employed. • Second order polynomial model produced adequately fitted experimental data. • Thermodynamic study inferred high temperature requirement for ethylene formation. • Turn-over-frequency at optimized responses is higher than the non-optimized process. - Abstract: Response surface methodology (RSM) and multi-objective genetic algorithm was employed to optimize the process parameters for catalytic conversion of glycerol, a byproduct from biodiesel production, to light olefins using Cu/ZSM-5 catalyst. The effects of operating temperature, weight hourly space velocity (WHSV) and glycerol concentration on light olefins selectivity and yield were observed. Experimental results revealed the data adequately fitted into a second-order polynomial model. The linear temperature and quadratic WHSV terms gave significant effect on both responses. Optimization of both the responses indicated that temperature favouring high light olefin formation lied beyond the experimental design range. The trend in the temperature profile concurred commensurately with the thermodynamic analysis. Multi-objective genetic algorithm was performed to attain a single set of processing parameters that could produce both the highest light olefin selectivity and yield. The turn-over-frequency (TOF) of the optimized responses demonstrated a slightly higher value than the one which was not optimized. Combination of RSM, multi-objective response and thermodynamic is useful to determine the process optimal operating conditions for industrial applications

  17. Recovery of Glycerol from Spent Soap LyeBy - Product of Soap Manufacture

    Directory of Open Access Journals (Sweden)

    A. U. Israel

    2008-01-01

    Full Text Available Three samples of spent lye from soap manufacturing companies namely Paterson Zochonis Industries (PZ, International Equitable Association (IEA, Kitchen Soap Industries (KSI all in Aba, Abia State of Nigeria and one laboratory simulated sample (SSL were analyzed for the amount of glycerol and residual salts. The amount of glycerol in all the samples increases in the order bleached glycerin > crude glycerin > semi-crude glycerin > treated lye > spent soap lye while the reverse is the order for the amount of residual salts. For the SSL, PZ, IEA and KSL samples, the percentage of recovered glycerol were 91.00, 83.20, 82.80 and 81.40 while the residual salt content (% were 9.80, 6.00, 7.08 and 8.03 respectively. These values compare well with international standards. The results show that the amount of the recovered glycerin and residual salts depend on the quality of the spent lye and the technology employed in the recovery treatment used.

  18. Biopolymer production using fungus Mucor racemosus Fresenius and glycerol as substrate

    Directory of Open Access Journals (Sweden)

    Thaíssa Rodrigues Araújo

    Full Text Available Abstract This study evaluated extracellular production of biopolymer using fungus Mucor racemosus Fresenius and glycerol as a carbon source. Initially employing conical flasks of 500 mL containing 100 mL of cultive medium with 0.18 ± 0.03 g.L–1 of microorganisms, the results showed that the best conditions of the variables studied were: initial concentration of glycerol 50 g.L–1, fermentation time of 96 h, inoculum cultivation time of 120 h, and aeration in two stages–the first 24 hours without aeration and 72 hours fermentation with aeration of 2 vvm and 2 g.L–1 of yeast extract. The experiments conducted in a Biostat B fermenter with a 2.0 L capacity that contained 1.0 L of medium showed production of 16.35 g.L–1 gum formed and 75% glycerol consumption. These conditions produced a biopolymer with the molecular weight and total sugar content of 4.607×106 g.mol–1 (Da and 89.5%, respectively.

  19. Lipid and carotenoid synthesis by Rhodosporidium diobovatum, grown on glucose versus glycerol, and its biodiesel properties.

    Science.gov (United States)

    Nasirian, Nima; Mirzaie, Maryam; Cicek, Nazim; Levin, David B

    2018-04-01

    Relationships between lipid and carotenoid synthesis by Rhodosporidium diobovatum were investigated for cell cultures in nitrogen-limited medium (GMY) containing equimolar amounts of carbon of glucose or glycerol. The cultures were also supplemented with additional substrate at 120 h postinoculation (pi) and during a fed-batch experiment. Growth of R. diobovatum on glucose resulted in higher yields of triacyglycerides (TAGs) and carotenoid than when grown on glycerol, even though the cultures contained equimolar amounts of carbon. After the addition of fresh substrate at 120 h pi, total carotenoid concentrations were significantly different from the concentrations measured at 120 h pi in both glucose and glycerol cultures, with no concomitant increase in lipid concentrations, suggesting that carotenoid synthesis is linked to exponential-phase growth, while lipid synthesis is linked to stationary phase. We also compared the calculated properties of biodiesel that could be made with TAGs derived from R. diobovatum with properties of biodiesel made from TAGs of other oleaginous yeasts, microalgae, vegetable oils, and animal fats. This study shows that R. diobovatum can be an effective strain for production of neutral lipids containing high percentages of oleic acid, palmitic acid, and linoleic acid, as well as carotenoids.

  20. Interfacial reaction using particle-immobilized reagents in a fluidized reactor. Determination of glycerol in biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Shishov, Andrey, E-mail: andrey.shishov.rus@gmail.com [Institute of Chemistry, Saint Petersburg State University, RU–198504 Saint Petersburg (Russian Federation); Zabrodin, Andrey; Moskvin, Leonid [Institute of Chemistry, Saint Petersburg State University, RU–198504 Saint Petersburg (Russian Federation); Andruch, Vasil [Department of Analytical Chemistry, University of P.J. Šafárik, SK-04154 Košice (Slovakia); Bulatov, Andrey [Institute of Chemistry, Saint Petersburg State University, RU–198504 Saint Petersburg (Russian Federation)

    2016-03-31

    A novel fluidized beads strategy for utilization of particle-immobilized reagents in flow analysis was developed in this study. The performance of the suggested strategy was demonstrated by the determination of glycerol in biodiesel. This analytical task was used as a proof-of-concept example. The method is based on on-line extraction of glycerol from biodiesel into aqueous stationary phase of extraction-chromatographic column, followed by elution and spectrophotometric determination in the form of copper glycerate formed in a fluidized reactor of stepwise injection system. The floating of cation exchange resin Dowex{sup ®} 50WX4, saturated with Cu(II) ions in liquid phase, was accomplished by air-bubbling. The linear range was from 100 to 1000 mg kg{sup −1}, and the limit of detection, calculated as 3s of a blank test (n = 5), was found to be 30 mg kg{sup −1}. The method was successfully applied to the analysis of biodiesel and biodiesel-blend (B 20) samples. - Highlights: • Novel fluidized beds strategy for utilization of particle-immobilized reagents. • First application of fluidized beds condition in SWIA. • Novel approach based on interfacial formation of copper glycerate. • Automated method for glycerol determination in biodiesel.

  1. 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.

  2. Reexamination of the evolution of the dynamic susceptibility of the glass former glycerol.

    Science.gov (United States)

    Adichtchev, S; Blochowicz, T; Tschirwitz, C; Novikov, V N; Rössler, E A

    2003-07-01

    The dielectric data of glycerol compiled by Lunkenheimer et al. [Contemp. Phys. 41, 15 (2000)] are reanalyzed within a phenomenological approach on the one hand, and within mode coupling theory (MCT), on the other. We present a complete interpolation of the dielectric data covering 17 decades in frequencies. The crossover temperature extracted from the phenomenological analysis of the slow response at low temperatures and defined by the emergence of the excess wing upon cooling agrees well with the critical temperature extracted from a MCT analysis of the dynamics at high temperatures including data that were not used in the first MCT analysis of glycerol by Lunkenheimer et al. [Phys. Rev. Lett. 77, 318 (1996)]. The crossover temperature is found to be T(c)=288+/-3 K, which is significantly higher than previously reported. Extracting the nonergodicity parameter f, the characteristic anomaly is only found when 1-f is inspected, since f is very close to 1. No difference for the evolution of the dynamic susceptibility is observed for the nonfragile system glycerol with respect to fragile glass formers provided that the evolution of the dynamics is studied as a function of the correlation time tau(alpha).

  3. Investigation of the kinetics and mechanism of the glycerol chlorination reaction using gas chromatography–mass spectrometry

    Directory of Open Access Journals (Sweden)

    JUN WANG

    2010-01-01

    Full Text Available As a primary by-product in biodiesel production, glycerol can be used to prepare an important fine chemical, epichlorohydrin, by the glycerol chlorination reaction. Although this process has been applied in industrial production, unfortunately, less attention has been paid to the analysis and separation of the compounds in the glycerol chlorination products. In this study, a convenient and accurate method to determine the products in glycerol chlorination reaction was established and based on the results the kinetic mechanism of the reaction was investigated. The structure of main products, including 1,3--dichloropropan-2-ol, 2,3-dichloropropan-1-ol, 3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol and glycerol was ascertained by gas chromatography–mass spectrometry and the isomers of the products were distinguished. Apidic acid was considered as the best catalyst because of its excellent catalytic effect and high boiling point. The mechanism of the glycerol chlorination reaction was proposed and a new kinetic model was developed. Kinetic equations of the process in the experimental range were obtained by data fitting and the activation energies of each tandem reaction were 30.7, 41.8, 29.4 and 49.5 kJ mol-1, respectively. This study revealed the process and mechanism of the kinetics and provides the theoretical basis for engineering problems.

  4. Conversion of 1-alkyl-2-acetyl-sn-glycerols to platelet activating factor and related phospholipids by rabbit platelets

    International Nuclear Information System (INIS)

    Blank, M.L.; Lee, T.; Cress, E.A.; Malone, B.; Fitzgerald, V.; Snyder, F.

    1984-01-01

    The metabolic pathway for 1-alkyl-2-acetyl-sn-glycerols, a recently discovered biologically active neutral lipid class, was elucidated in experiments conducted with rabbit platelets. The total lipid extract obtained from platelets incubated with 1-[1-,2- 3 H]alkyl-2-acetyl-sn-glycerols or 1-alkyl-2-[ 3 H]acetyl-sn-glycerols contained at least six metabolic products. The six metabolites, identified on the basis of chemical and enzymatic reactions combined with thin-layer or high-performance liquid chromatographic analyses, corresponded to 1-alkyl-sn-glycerols, 1-alkyl-2-acetyl-sn-glycero-3-phosphates, 1-alkyl-2-acyl(long-chain)-sn-glycero-3-phosphoethanolamines, 1-alkyl-2-acetyl-sn-glycero-3-phosphoethanolamines, 1-alkyl-2-acyl(long-chain)-sn-glycero-3-phosphocholines, and 1-alkyl-2-actyl-sn-glycero-3-phosphocholines (platelet activating factor). These results indicate that the metabolic pathway for alkylacetylglycerols involves reaction steps catalyzed by the following enzymatic activities: choline- and ethanolamine- phosphotransferases, acetyl-hydrolase, an acyltransferase, and a phosphotransferase. The step responsible for the biosynthesis of platelet activating factor would appear to be the most important reaction in this pathway and this product could explain the hypotensive activities previously described for alkylacetyl-(or propionyl)-glycerols. Of particular interest was the preference exhibited for the utilization of the 1-hexadecyl-2-acetyl-sn-glycerol species in the formation of platelet activating factor

  5. Non-Catalytic and MgSO4 - Catalyst based Degradation of Glycerol in Subcritical and Supercritical Water Media

    Directory of Open Access Journals (Sweden)

    Mahfud Mahfud

    2011-02-01

    Full Text Available This research aims to study the glycerol degradation reaction in subcritical and supercritical water media. The degradation of glycerol into other products was performed both with sulphate salt catalysts and without catalyst. The reactant was made from glycerol and water with the mass ratio of 1:10. The experiments were carried out using a batch reactor at a constant pressure of 250 kgf/cm2, with the temperature range of 200-400oC, reaction time of 30 minutes, and catalyst mol ratio in glycerol of 1:10 and 1:8. The products of the non-catalytic glycerol degradation were acetaldehyde, methanol, and ethanol. The use of sulphate salt as catalyst has high selectivity to acetaldehyde and still allows the formation alcohol product in small quantities. The mechanism of ionic reaction and free radical reaction can occur at lower temperature in hydrothermal area or subcritical water. Conversion of glycerol on catalytic reaction showed a higher yield when compared with the reaction performed without catalyst

  6. THE DEPENDENCE OF GLYCEROL ACCUMULATION AND STARCH HYDROLYZATES FERMENTATION FROM WORT CONCENTRATION

    Directory of Open Access Journals (Sweden)

    Оliynichuk S. Т.

    2015-08-01

    Full Text Available The purpose of this work is to study the dependence of ethanol accumulation by-products and secondary products (glycerol and propionic acid during the fermentation in the case of increasing the wort concentration from 12 to 21% by weight of sugar as an example of commonly used in the alcohol industry the commercial dry yeast company “Danisco” and experimental osmophilic strain Saccharomyces cerevisiae DS-02-E, isolated from a concentrated (80% DM of rye malt wort which spontaneously fermented. The enzyme preparations “AMYLEX 4T”, “ALPHALASE AFP” and “DIAZYME SSF” were used for the liquefaction and saccharification of starch wort. The finished industrial of both yeast strains were added to the fermentation flasks in an amount of 10% by volume of the primary wort. In the mature brew the unfermented carbohydrates content was determined by colorimetric method with anthrone reagent, alcohol — by glass areometer-alcoholometer, acidity — potentiometrically, the concentration of dry matter — by areometer, glycerol content — by photocolorimetry method. In the brew distillate a volatile impurities content, namely propionic acid, was determined using gas chromatography. Statistical processing of the results of three series of experiments were carried out by calculating the arithmetical mean value of 5 measurements, their standard deviations and errors. To determine the probable differences between the mean values were used Student’s t test. Differences were considered statistically significant at P < 0.05. Reduction for accumulation of glycerol (between 38 till 53% at higher concentrations of nutrient medium in the case of the yeast Saccharomyces cerevisiae DS-02-E as compared with commercial dry yeast, reduction the formation of unwanted by-product of fermentation — propionic acid (up to 34%, a better ability of the experimental strain to accumulate sugar of wort and to accumulate ethanol (up to 0.1–0.25% vol. were shown. It

  7. Biodiesel production using heterogeneous catalysts including wood ash and the importance of enhancing byproduct glycerol purity

    International Nuclear Information System (INIS)

    Uprety, Bijaya K.; Chaiwong, Wittavat; Ewelike, Chinomnso; Rakshit, Sudip K.

    2016-01-01

    Highlights: • Comparison of biodiesel production using homogeneous and heterogeneous catalysts. • Comparative study of CaO and CaO supported on alumina for biodiesel production. • Tradeoff between biodiesel conversion rate and purity. • Ash from birch bark and wood pellet industry explored as a potential catalyst. - Abstract: Transesterification of vegetable oils or animal fats with methanol in the presence of catalysts produces fatty acid methyl esters (FAME) and glycerol as a co-product. This study was focused on a comparative study of the transesterification of refined, bleached and deodorized palm oil (RBD palm oil) using a heterogeneous catalysts CaO with and without γ-alumina (γ-Al_2O_3) as a support. The results were also compared to that using sodium hydroxide (NaOH), which is a homogenous catalyst. Parameters like the amount of catalyst, the molar ratio of methanol to oil, reaction time and reaction temperature that affect methyl ester and glycerol formation were analyzed and the optimum conditions were determined. The FAME and glycerol content (96.75% and 92.73% respectively) obtained using CaO were lower in purity compared to that using CaO/Al_2O_3 (97.66% and 96.36% respectively). In the second phase of our work, wood ash from two different sources (birch bark & flyash from a biomass based power plant), which were calcined at 800 °C were studied for their potential use as a cheap renewable alternative heterogeneous catalyst. Both the wood ash samples were found to have good potential for use in such production process, but needs to be optimized further to obtain biodiesel which meets fuel biodiesel specifications. Both CaO and CaO supported on alumina produces FAME to levels that meet the fuel specifications required for blending with diesel. However, the latter produces a purer form of byproduct glycerol that can be easily converted to value added products, without the need for purification. On this basis the supported catalyst is

  8. A novel route to synthesis of glycerol dimethyl ether from epichlorohydrin with high selectivity

    International Nuclear Information System (INIS)

    Ding, Xiaoshu; Liu, Hao; Yang, Qiusheng; Li, Naihua; Dong, Xiangmo; Wang, Shufang; Zhao, Xinqiang; Wang, Yanji

    2014-01-01

    The effective utilization of glycerol, a by-product in the production of biodiesel, into useful chemicals is desirable from the viewpoint of green chemistry. With this in mind, a novel and highly selective route to synthesizing glycerol dimethyl ether (2,3-dimethoxy-1-propanol), a potential fuel additive, from glycerol was proposed. This route uses both glycerol and methanol as starting materials, takes epichlorohydrin as an intermediate product, and utilizes HCl as a recycling agent. Hereinto, the key step of this route is the reaction between epichlorohydrin and methanol to produce 2,3-dimethoxy-1-propanol which is identified by GC–MS, ESI-MS, IR and NMR. The thermodynamics of this reaction was analyzed and the result showed that the thermodynamics of a reaction was favorable and a high product yield was expected. The effect of various parameters such as kind of acid catalyst, molar ratio of epichlorohydrin to methanol, reaction temperature and reaction time was studied. Among various acid catalysts investigated, the acidic ionic liquid [HSO 3 -b-N(CH 3 ) 3 ]HSO 4 exhibited the highest activity and selectivity: conversion of epichlorohydrin of 100% and selectivity of 2,3-dimethoxy-1-propanol of 99% at 393 K, 10 h, an initial pressure of 0.1 MPa and a molar ratio of catalyst:ECH:CH 3 OH of 0.01:1:5. After the reaction, [HSO 3 -b-N(CH 3 ) 3 ]HSO 4 was separated by vacuum distillation and then reused for the next cycle directly. The results showed that the product selectivity remained at about 94% but the conversion of epichlorohydrin dropped to 75% after being used five times. Subsequently, a reaction mechanism for the synthesis of 2,3-dimethoxy-1-propanol from epichlorohydrin and methanol was proposed. - Highlights: • Epichlorohydrin was converted effectively into glycerol dimethyl ether used as potential fuel additive. • The selectivity of 99% and the conversion of 100% under the mild reaction condition. • The reaction was high product selectivity and

  9. Quantitative Analysis of Phenylpropanoid Glycerol Glucosides in Different Organs of Easter Lily (Lilium longiflorum Thunb.).

    Science.gov (United States)

    Munafo, John P; Gianfagna, Thomas J

    2015-05-20

    The Easter lily (Lilium longiflorum Thunb.) is esteemed worldwide as an attractive ornamental plant, and the flower buds and bulbs are used for both culinary and medicinal purposes in many parts of the world. L. longiflorum contains significant amounts of phenylpropanoid glycerol glucosides, a group of compounds that may contribute to plant pathogen defense, ultraviolet/high-intensity visible light (UV/high light) protection, and the purported medicinal uses of lilies. To define the natural distribution of these compounds within the plant, a liquid chromatography-mass spectrometry (LC-MS) method performed in selected ion monitoring (SIM) mode was employed for the quantitative analysis of five phenylpropanoid glycerol glucosides, namely, (2S)-1-O-caffeoyl-2-O-β-D-glucopyranosylglycerol, 1; (2R)-1-O-β-D-glucopyranosyl-2-O-p-coumaroylglycerol, 2; (2S)-1-O-p-coumaroyl-2-O-β-D-glucopyranosylglycerol, 3; (2S)-1-O-caffeoyl-2-O-β-D-glucopyranosyl-3-O-acetylglycerol, 4; and (2S)-1-O-p-coumaroyl-2-O-β-D-glucopyranosyl-3-O-acetylglycerol, 5, in the different organs of L. longiflorum. The p-coumaroyl-based 3 and its acetylated derivative 5 were determined to be the most abundant of the phenylpropanoid glycerol glucosides found in Easter lily bulbs, at 776.3 ± 8.4 and 650.7 ± 32.6 μg/g dry weight, respectively. The acetylated p-coumaroyl- and caffeoyl-based derivatives, 5 and 4, accumulated to the highest concentration in the closed flower buds, at 4925.2 ± 512.8 and 3216.8 ± 406.4 μg/g dry weight, respectively. Compound 4, followed by 5 and 1, proved to be the most abundant in the mature flowers, occurring at 6006.2 ± 625.8, 2160.3 ± 556.5, and 1535.8 ± 174.1 μg/g dry weight, respectively. Total concentrations of the phenylpropanoid glycerol glucosides were 10-100-fold higher in the above-ground plant organs as compared to the bulbs and fleshy roots. Two of the five compounds, 1 and 2, were identified in L. longiflorum for the first time. The quantitative

  10. Covalent immobilization of lipase, glycerol kinase, glycerol-3-phosphate oxidase & horseradish peroxidase onto plasticized polyvinyl chloride (PVC strip & its application in serum triglyceride determination

    Directory of Open Access Journals (Sweden)

    Nidhi Chauhan

    2014-01-01

    Full Text Available Background & objectives:Reusable biostrip consisting enzymes immobilized onto alkylamine glass beads affixed on plasticized PVC strip for determination of triglyceride (TG suffers from high cost of beads and their detachments during washings for reuse, leading to loss of activity. The purpose of this study was to develop a cheaper and stable biostrip for investigation of TG levels in serum. Methods: A reusable enzyme-strip was prepared for TG determination by co-immobilizing lipase, glycerol kinase (GK, glycerol-3-phosphate oxidase (GPO and peroxidase (HRP directly onto plasticized polyvinyl chloride (PVC strip through glutaraldehyde coupling. The method was evaluated by studying its recovery, precision and reusability. Results: The enzyme-strip showed optimum activity at pH 7.0, 35 o C and a linear relationship between its activity and triolein concentration in the range 0.1 to 15 mM. The strip was used for determination of serum TG. The detection limit of the method was 0.1 mM. Analytical recovery of added triolein was 96 per cent. Within and between batch coefficients of variation (CV were 2.2 and 3.7 per cent, respectively. A good correlation (r=0.99 was found between TG values by standard enzymic colrimetric method employing free enzymes and the present method. The strip lost 50 per cent of its initial activity after its 200 uses during the span of 100 days, when stored at 4 o C. Interpretation & conclusions: The nitrating acidic treatment of plasticized PVC strip led to glutaraldehyde coupling of four enzymes used for enzymic colourimetric determination of serum TG. The strip provided 200 reuses of enzymes with only 50 per cent loss of its initial activity. The method could be used for preparation of other enzyme strips also.

  11. Insights into the biological source and environmental gradients shaping the distribution of H-shaped glycerol dialkyl glycerol tetraethers in Yellowstone National Park geothermal springs

    Science.gov (United States)

    Jia, C.; Xie, W.; Wang, J.; Boyd, E. S.; Zhang, C.

    2013-12-01

    Archaea are ubiquitous in natural environments. The unique tetraether lipids in archaeal membranes enable the maintenance of ion permeability across broad environmental gradients. H-shaped isoprenoid glycerol dialkyl glycerol tetraethers (H-GDGTs), in which the two biphytanyl carbon skeletons are covalently bound by a carbon-carbon bond, have been recently identified in both marine and geothermal environments. Here we report the core H-GDGTs (C-H-GDGTs) and polar H-GDGTs (P-H-GDGTs) associated with sediments sampled from geothermal springs in Yellowstone National Park and investigate their abundance in relation to environmental gradients. The abundance of C- and P-H-GDGTs exhibit strong and negative correlation with pH (P = 0.007), suggesting that H-shaped GDGTs help to maintain cell membrane fluidity in acidic environments. Reanalysis of archaeal 16S rRNA gene pyrotags published previously from (Boyd E. Hamilton T. L., Wang J., He L., Zhang C. L. 2013. The role of tetraether lipid composition in the adaptation of thermophilic archaea to acidity. Frontiers in Terrestrial Microbiology. 4: doi: 10.3389/fmicb.2013.00062) indicates that these H-GDGTs are associated with environments dominanted by Thermoplasmatales, which are thermoacidiphiles. Two equations were established to define the relationships between the abundance of H-GDGTs, the abundance of archaeal taxa based on 16S rRNA gene phylogenetic affiliations, and pH. Both equations have high predictive capacity in predicting the distribution of archaeal lipids in the geothermal system. These observations provide new insight into the biological source of H-GDGTs and suggest a prominent role for these lipids in the diversification of archaea into or out of acidic high temperature environments.

  12. Distribution of branched glycerol dialkyl glycerol tetraethers in surface soils of the Qinghai–Tibetan Plateau: implications of brGDGTs-based proxies in cold and dry regions

    Directory of Open Access Journals (Sweden)

    S. Ding

    2015-06-01

    Full Text Available The methylation index of branched tetraethers (MBT and cyclization ratio of branched tetraethers (CBT based on the distribution of branched glycerol dialkyl glycerol tetraethers (brGDGT are useful proxies for the reconstruction of mean annual air temperature (MAT and soil pH. Recently, a series of 6-methyl brGDGTs were identified which were previously co-eluted with 5-methyl brGDGTs. However, little is known about 6-methyl brGDGTs in the Qinghai–Tibetan Plateau (QTP, a critical region of the global climate system. Here, we analyze 30 surface soils covering a large area of the QTP, among which 6-methyl brGDGTs were the most abundant components (average 53 ± 17% of total brGDGT. The fractional abundance of 6-methyl brGDGTs showed a good correlation with soil pH, while the global MBT'5ME calibration overestimates MAT in the QTP. We therefore proposed a MBT5/6 index including both 5- and 6-methyl brGDGTs, presenting a strong correlation with MAT in QTP: MAT = −20.14 + 39.51 × MBT5/6 (n = 27, r2 = 0.82; RMSE = 1.3 °C. Another index, namely IBT (isomerization of branched tetraether, based on carbon skeleton isomerization of the 5-methyl to 6-methyl brGDGTs, is dependent on soil pH: pH = 6.77 − 1.56 × IBT (n = 27; r2 = 0.74, RMSE = 0.32. Our study suggests that changing the position of methyl group of brGDGTs may be another mechanism for some soil bacteria to adapt to the ambient pH change in addition to the well-known cyclization.

  13. Synthetic Klebsiella pneumoniae-Shewanella oneidensis Consortium Enables Glycerol-Fed High-Performance Microbial Fuel Cells.

    Science.gov (United States)

    Li, Feng; Yin, Changji; Sun, Liming; Li, Yuanxiu; Guo, Xuewu; Song, Hao

    2018-05-01

    Microbial fuel cell (MFC) is an eco-friendly bio-electrochemical sys-tem that uses microorganism as biocatalyst to convert biomass into electricity. Glycerol, as a waste in the biodiesel refinery processes, is an appealing substrate for MFC. Nevertheless, glycerol cannot be utilized as carbon source by well-known exoelectrogens such as Shewanella oneidensis. Herein, to generate electricity by rapidly harnessing glycerol, the authors rationally constructed a Klebsiella pneumoniae-Shewanella oneidensis microbial consortium to efficiently harvest electricity from glyc-erol, in which K. pneumoniae converted glycerol into lactate, fed to S. oneidensis as carbon source and electron donor. To improve electricity output, the authors systematically engineered the consortium in terms of carbon flux distribution and efficiency of extracellular electron transfer (EET). To direct more carbon flux to lactate biosynthesis in K. pneumoniae, the authors eliminated the ethanol pathway by knocking out the alcohol dehydrogenase gene (adhE), and enhanced lactate biosynthesis by heterologously expressing a lactate dehydrogen-ase gene (ldhD) from Lactobacillus bulgaricus and a lactate transporter gene (lldP) from Escherichia coli. To facilitate EET between S. oneidensis and anode surfaces, a biosynthetic flavins pathway from Bacillus subtilis is introduced into S. oneidensis. The author further optimized the glycerol concentration, thus S. oneidensis could be continuously fed with lactate synthesized from K. pneumoniae at a constant rate. Our glycerol-fed MFC generated a maximum power density of 19.9 mW/m 2 , significantly higher than that of the wild-type consor-tium. This work suggested that engineering microbial consortia is an effi-cient strategy to expand the spectrum of usable carbon sources and promote electricity power production in MFCs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Improved glycerol to ethanol conversion by E. coli using a metagenomic fragment isolated from an anaerobic reactor.

    Science.gov (United States)

    Loaces, Inés; Rodríguez, Cecilia; Amarelle, Vanesa; Fabiano, Elena; Noya, Francisco

    2016-10-01

    Crude glycerol obtained as a by-product of biodiesel production is a reliable feedstock with the potential to be converted into reduced chemicals with high yields. It has been previously shown that ethanol is the primary product of glycerol fermentation by Escherichia coli. However, few efforts were made to enhance this conversion by means of the expression of heterologous genes with the potential to improve glycerol transport or metabolism. In this study, a fosmid-based metagenomic library constructed from an anaerobic reactor purge sludge was screened for genetic elements that promote the use and fermentation of crude glycerol by E. coli. One clone was selected based on its improved growth rate on this feedstock. The corresponding fosmid, named G1, was fully sequenced (41 kbp long) and the gene responsible for the observed phenotype was pinpointed by in vitro insertion mutagenesis. Ethanol production from both pure and crude glycerol was evaluated using the parental G1 clone harboring the ethanologenic plasmid pLOI297 or the industrial strain LY180 complemented with G1. In mineral salts media containing 50 % (v/v) pure glycerol, ethanol concentrations increased two-fold on average when G1 was present in the cells reaching up to 20 g/L after 24 h fermentation. Similar fermentation experiments were done using crude instead of pure glycerol. With an initial OD620 of 8.0, final ethanol concentrations after 24 h were much higher reaching 67 and 75 g/L with LY180 cells carrying the control fosmid or the G1 fosmid, respectively. This translates into a specific ethanol production rate of 0.39 g h(-1) OD(-1) L(-1).

  15. 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)

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

    Directory of Open Access Journals (Sweden)

    Farokh Kafilzadeh

    2015-12-01

    Full Text Available 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.

  17. 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

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

    OpenAIRE

    Hong Yang; Yun-Tao Cao; Hao Song; Shao-Feng Hua; Chun-Gu Xia; Wei-Bao Kong

    2013-01-01

    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 ...

  19. Collagen-chitosan-glycerol bio-composite as artificial tympanic membrane for ruptured inner ear organ

    Science.gov (United States)

    Widiyanti, Prihartini; Setya Angtika, Rara; Githanadi, Brillyana; Hanif Kharisma, Ditya; Asyraf, Tarikh Omar; Wardani, Adita

    2017-05-01

    WHO data in 2012 shows that 5.3% of world population highly suffers from hearing loss and deafness. One of the deafness causes is rupture of tympanic membrane. Tympanic membrane damage which occurs often is perforated tympanic membrane, and it is also commonly known in medical term as tympanic membrane perforation. The causes, for instance, are high frequency of using earphones, traumatic accidents, noise, bacteria, viruses, and infectious microorganism. Tympanoplasty becomes the only treatment that can be widely accepted despite of deficiencies in postoperative complications. Therefore, this research aims to create artificial tympanic membrane made of natural materials such as type I collagen composited with chitosan and made of addition of glycerol to improve its mechanical strength and biodegradability. The method included the process of dissolving acetic acid in distilled water and mixation with chitosan. The solution is next added with glycerol and stirred to be homogeneous. After that, it was minted in petri dish and aerated before characterized. The sample characterization included tensile strength of which tensile test results showed that the value of the elasticity modulus tended to decrease with an increase in collagen concentration. The elasticity modulus values in a row for the variations of 7: 3, 8: 2, and 9: 1 were 35.10 MPa, 54,52MPa, and 47,45MPa respectively. The morphological test with 1000x, 2500x, and 5000x magnification showed their interaction in the formation of pores. Cytotoxicity results, moreover, showed that those samples were non-toxic and safe for the body due to the percentage of living cells. The sound absorption coefficient was between 1000 Hz - 2000 Hz which means that it could use as sound absorbing material. The antibacterial test results showed that all the sample variations were anti-bacterial due to the diameter of the clear zone. In conclusion, collagen and chitosan composite with addition of glycerol could be used for

  20. Catalytic Glycerol Hydrodeoxygenation under Inert Atmosphere: Ethanol as a Hydrogen Donor

    Directory of Open Access Journals (Sweden)

    Efterpi S. Vasiliadou

    2014-12-01

    Full Text Available Glycerol hydrodeoxygenation to 1,2-propanediol (1,2-PDO is a reaction of high interest. However, the need for hydrogen supply is a main drawback of the process. According to the concept investigated here, 1,2-propanediol is efficiently formed using bio-glycerol feedstock with H2 formed in situ via ethanol aqueous phase reforming. Ethanol is thought to be a promising H2 source, as it is alcohol that can be used instead of methanol for transesterification of oils and fats. The H2 generated is consumed in the tandem reaction of glycerol hydrodeoxygenation. The reaction cycle proceeds in liquid phase at 220–250 °C and 1.5–3.5 MPa initial N2 pressure for a 2 and 4-h reaction time. Pt-, Ni- and Cu-based catalysts have been synthesized, characterized and evaluated in the reaction. Among the materials tested, Pt/Fe2O3-Al2O3 exhibited the most promising performance in terms of 1,2-propanediol productivity, while reusability tests showed a stable behavior. Structural integrity and no formation of carbonaceous deposits were verified via Temperature Programmed Desorption of hydrogen (TPD-H2 and thermogravimetric analysis of the fresh and used Pt/FeAl catalyst. A study on the effect of various operating conditions (reaction time, temperature and pressure indicated that in order to maximize 1,2-propanediol productivity and yield, milder reaction conditions should be applied. The highest 1,2-propanediol yield, 53% (1.1 g1,2-PDO gcat−1·h−1, was achieved at a lower reaction temperature of 220 °C.

  1. 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.

  2. Mechanical properties and total hydroxycinnamic derivative release of starch/glycerol/Melissa officinalis extract films

    Directory of Open Access Journals (Sweden)

    Letícia Mello Rechia

    2010-09-01

    Full Text Available The aim of this study was to investigate the mechanical properties of starch/glycerol/Melissa officinalis, a topical drug delivery system for labial herpes treatment. Four films were prepared with different concentrations of starch, glycerol, and Melissa officinalis extract. The results revealed that increasing the glycerol concentration in the film reduced elasticity modulus and tensile strength, exhibiting a plasticizing effect. The increase in free volume resulted in increased release of hydroxycinnamic derivatives expressed as rosmarinic acid.O objetivo deste trabalho foi estudar as propriedades mecânicas e o mecanismo de liberação de um sistema tópico de liberação prolongada para o tratamento do Herpes labial a partir de filmes de amido/glicerol/extrato de Melissa officinalis, planta com comprovada atividade antiviral. Foram obtidos quatro filmes poliméricos com diferentes concentrações de amido, glicerol e extrato de Melissa officinalis os quais foram caracterizados mecanicamente e determinado o perfil de liberação de derivados hidroxicinâmicos. Os resultados demonstraram que o aumento da concentração de glicerol no filme produz uma redução no módulo de elasticidade e na tensão de deformação como conseqüência do efeito plastificante. O aumento no volume livre do polímero resultou em aumento da liberação dos derivados hidroxicinâmicos expressos como ácido rosmarínico.

  3. Effects of Time-Release Caffeine Containing Supplement on Metabolic Rate, Glycerol Concentration and Performance

    Directory of Open Access Journals (Sweden)

    Adam M. Gonzalez, Jay R. Hoffman, Adam J. Wells, Gerald T. Mangine, Jeremy R. Townsend, Adam R. Jajtner, Ran Wang, Amelia A. Miramonti, Gabriel J. Pruna, Michael B. LaMonica, Jonathan D. Bohner, Mattan W. Hoffman, Leonardo P. Oliveira, David H. Fukuda, Maren S. Fragala, Jeffrey R. Stout

    2015-06-01

    Full Text Available This study compared caffeine pharmacokinetics, glycerol concentrations, metabolic rate, and performance measures following ingestion of a time-release caffeine containing supplement (TR-CAF versus a regular caffeine capsule (CAF and a placebo (PL. Following a double-blind, placebo-controlled, randomized, cross-over design, ten males (25.9 ± 3.2 y who regularly consume caffeine ingested capsules containing either TR-CAF, CAF, or PL. Blood draws and performance measures occurred at every hour over an 8-hour period. Plasma caffeine concentrations were significantly greater (p < 0.05 in CAF compared to TR-CAF during hours 2-5 and significantly greater (p = 0.042 in TR-CAF compared to CAF at hour 8. There were no significant differences between trials in glycerol concentrations (p = 0.86 or metabolic measures (p = 0.17-0.91. Physical reaction time was significantly improved for CAF at hour 5 (p=0.01 compared to PL. Average upper body reaction time was significantly improved for CAF and TR-CAF during hours 1-4 (p = 0.04 and p = 0.01, respectively and over the 8-hour period (p = 0.04 and p = 0.001, respectively compared to PL. Average upper body reaction time was also significantly improved for TR-CAF compared to PL during hours 5-8 (p = 0.004. TR-CAF and CAF showed distinct pharmacokinetics yielding modest effects on reaction time, yet did not alter glycerol concentration, metabolic measures, or other performance measures.

  4. Synthesis and characterization of a glycerol salicylate resin for bioactive root canal sealers.

    Science.gov (United States)

    Portella, F F; Santos, P D; Lima, G B; Leitune, V C B; Petzhold, C L; Collares, F M; Samuel, S M W

    2014-04-01

    To develop and characterize a salicylate resin with potential use in bioactive endodontic sealers. Methyl salicylate, glycerol and titanium isopropoxide were added in a closed system for the transesterification reaction. The resin obtained was characterized by proton nuclear magnetic resonance spectroscopy (1H NMR) and size exclusion chromatography (SEC). To verify the applicability of the resin to the development of endodontic sealers, experimental cements were prepared by mixing glycerol salicylate resin, calcium hydroxide and methyl salicylate in the ratios of 2 : 1 : 1, 1 : 2 : 1, 1 : 1 : 2, 1 : 1 : 1, 4 : 1 : 1, 1 : 4 : 1 and 1 : 1 : 4. Setting times were measured according to ISO 6876. Features of the hardening reaction were described by micro-RAMAN spectroscopy. The transesterification reaction had a 72% efficiency. The (1) H NMR analysis revealed the presence of the expected functional groups (hydroxyls and aromatic rings), and the SEC confirmed the molar mass of the resin produced. The setting times of experimental sealers ranged from 70 min (ratio 1 : 1 : 1) to 490 min (ratio 1 : 1 : 4). The conversion of the salicylic groups (1 613 cm(-1) ) to salicylate salt (1 543 cm(-1) ) and the reduction in calcium hydroxide peaks (1084 and 682 cm(-1) ) were confirmed by micro-RAMAN spectroscopy, which showed the calcium chelation by the resin. The new glycerol salicylate resin was successfully synthesized and revealed a potential application in the development of endodontic sealers. © 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  5. Production of gaseous and liquid chemicals by aqueous phase reforming of crude glycerol: Influence of operating conditions on the process

    International Nuclear Information System (INIS)

    Remón, J.; Giménez, J.R.; Valiente, A.; García, L.; Arauzo, J.

    2016-01-01

    Highlights: • Aqueous phase reforming: a tailor-made process for the valorisation of crude glycerol. • In-depth understanding of the effect of the operating conditions on the process. • Process optimisation for the selective production of valuable gas and liquid products. • Low pressure and high temperature and spatial time favour gas production. • High pressure and medium temperature maximise the production of valuable liquids. - Abstract: The present work studies the influence of the temperature (200–240 °C), pressure (38–50 bar), glycerol concentration (10–50 wt.%) and mass of catalyst/ glycerol mass flow rate ratio (W/m_g_l_y_c_e_r_o_l = 10–40 g catalyst min/g glycerol) during the aqueous phase reforming (APR) of a glycerol solution obtained from the production of biodiesel. The operating conditions exerted a statistically significant influence on the reforming results. Specifically, the global glycerol conversion and the carbon converted into gas and liquid products varied as follows: 4–100%, 1–80% and 16–93%, respectively. The gas phase was made up of H_2 (8–55 vol.%), CO_2 (34–66 vol.%), CO (0–4 vol.%) and CH_4 (6–45 vol.%). The liquid phase consisted of a mixture of alcohols (monohydric: methanol and ethanol; and polyhydric: 1,2-propanediol, 1,2-ethanediol, 2,3-butanediol), aldehydes (acetaldehyde), ketones (C3-ketones: acetone and 2-propanone-1-hydroxy; C4-ketones: 2-butanone-3-hydroxy and 2-butanone-1-hydroxy; and cyclic ketones), carboxylic acids (acetic and propionic acids) and esters (1,2,3-propanetriol-monoacetate), together with unreacted glycerol and water. The relative amount (free of water and un-reacted glycerol) of these compounds in the liquid phase was as follows: monohydric alcohols: 4–47%, polyhydric-alcohols: 14–68%, aldehydes: 0–5%, C3-ketones: 2–33%, C4-ketones: 0–10%, ciclo-ketones: 0–6%, carboxylic acids: 2–43%, and esters: 0–46%. This process turned out to be highly customisable for the

  6. The influence of glycerol on γ-induced mutagenesis in Salmonella typhimurium cells

    International Nuclear Information System (INIS)

    Basha, S.G.; Krasavin, E.A.; Kozubek, S.; Amirtaev, K.G.

    1990-01-01

    A study was made of the modifying effect of glycerol on the survival rate and γ-radiation-induced mutagenesis of Salmonella typhimurium cells TA98, TA100 and TA102. The DMF value, with respect to the survival rate, was 2.05-0.20. The dependence of the yield of γ-radiation-induced mutants on radiation dose was described by the curve with a maximum; the mutation frequency M(D) was well described by a gradual function M(D)=kD x . DMF values of the induced mutagenesis amounted to 2 for strains TA100 and TA102, and 1.5 for strain TA98

  7. Techno-economic risk analysis of glycerol biorefinery concepts against market price fluctuation

    DEFF Research Database (Denmark)

    Gargalo, Carina L.; Cheali, Peam; Gernaey, Krist

    . The high-value added bio-products boost profitability, the high-volume fuel helps meet national energy targets, and the power production cuts costs and dodges greenhouse-gas emissions [1] [2] [3]. The increasing amount of biodiesel production worldwide (e.g. from vegetable oils, palm oil, animal fats......) and the associated economic risks against historical market fluctuations when assessing the economics of competing glycerol biorefinery concepts. The aim is to compare the fitness/survival of the biorefinery concepts under extreme market disturbances. To perform this analysis, we used a superstructure based...

  8. Effect of succinic acid concentration in poly(glycerol citrate/succinate) properties

    International Nuclear Information System (INIS)

    Brioude, Michel M.; Guimaraes, Danilo H.; Fiuza, Raigenis P.; Jose, Nadia M.

    2011-01-01

    In this work were prepared and characterized polymer based on glycerol, citric and succinic acid, in three different ratios to evaluate the effect of succinic acid concentration in materials properties. The polymers were obtained by polycondensation reaction between polyol and poly acids, and were characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning differential calorimetry (DSC), scanning electron microscopy (SEM). The materials are amorphous polyesters and its thermal and morphological properties change depending on the succinic acid concentration. (author)

  9. Investigations with tritium-labelled glycerol of the triglyceride metabolism in patients

    International Nuclear Information System (INIS)

    Leonhardt, W.; Julius, U.; Koch, R.; Schulze, J.

    1980-01-01

    Triglycerides, being components of lipoproteins, are secreted by the liver into the blood and climinated from the blood by adipose and muscle tissue. The kinetics of this metabolic pathway were studied after injection of tritium-labelled glycerol which is incorporated into triglycerides by the liver. The serum triglyceride radioactivity-time curve was analysed with a computer. 99 examinations showed a decrease of the fractional turnover rate and an increase of the turnover rate with the triglyceride level. The test enables to decide whether an increased triglyceride concentration is caued by overproduction or by disturbed climination. (author)

  10. Rheological and thermal characteristics of wheat gluten biopolymers plasticized with glycerol

    Directory of Open Access Journals (Sweden)

    Shana Pires Ferreira

    2012-01-01

    Full Text Available The objective this work was to obtain bioplastics from mixtures of wheat gluten and glycerol by two different processes and evaluate their respective rheological properties. The mixtures and their respective bioplastics were obtained through direct batch mixing under approximately adiabatic and isothermal conditions. The bioplastics showed high values for the storage (G' and loss (G" moduli, suggesting a stronger protein network formed in both processes. The temperature onset and the percentage of weight loss to be estimated were found to be near in both bioplastics. The bioplastics have demonstrated to be materials of interesting potential of use as biodegradable barrier materials.

  11. Elastomeric Properties of Poly(glycerol sebacate) (PGS) Based Nanoparticle Composites

    Science.gov (United States)

    Chung, Hyun-Joong; Li, Xinda; Hong, Albert T.-L.

    2014-03-01

    Owing to the unique combination of biocompatible, biodegradable, and elastomeric properties, poly(glycerol sebacate) and their derivatives are an emerging class of biomaterials for soft tissue replacement, drug delivery, tissue adhesive, and hard tissue regeneration. The mechanical properties of the polyester have been tailored to match a wide range of target organs, ranging from cardiac muscle to bones, by manipulating the process parameters to modulate cross-linking density. In the present study, we applied nanoparticles and cross-linking agents to further optimize their elastomeric properties. Especially, the study aims to enhance the practically important, but less studied, property of tear resistance. Microscopic origin of the property enhancement is discussed.

  12. Glycerol oxidehydration into acrolein and acrylic acid over W/V/Nb bronzes with hexagonal structure

    Energy Technology Data Exchange (ETDEWEB)

    Basile, F.; Cavani, F.; Chieregato, A. [Bologna Univ. (Italy). Dipt. di Chimica Industriale e dei Materiali; CIRI Energia e Ambiente, Bologna (Italy); Concepcion, P.; Lopez Nieto, J.M.; Soriano, M.D. [Univ. Politecnica de Valencia (Spain). Inst. de Tecnologia Quimica; Liosi, G.; Trevisanut, C. [Bologna Univ. (Italy). Dipt. di Chimica Industriale e dei Materiali

    2012-07-01

    This paper deals with an investigation of hexagonal W-V-Nb-O and W-V-Mo-O bronzes as catalysts for the one-pot oxidehydration of glycerol into acrylic acid. In a previous work, we reported a study on a bi-component bronze W-V-O that allowed us to obtain a 25% acrylic acid selectivity; in the current work, the incorporation of either Nb or Mo in a tri-component bronze structure allowed us to tune the acid and redox properties of the catalyst, so as to study their influence on the overall reaction scheme. (orig.)

  13. Apposite of pig skin preserved in glycerol; Apositos de piel de cerdo preservados en glicerol

    Energy Technology Data Exchange (ETDEWEB)

    Reyes F, M.L.; Gonzalez V, C.; Salinas A, M. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)

    2007-07-01

    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)

  14. Glycerol carbonate in Ferrier reaction: Access to new enantiopure building blocks to develop glycoglycerolipid analogues.

    Science.gov (United States)

    da Costa, Pollyanna Leite Ferreira; Melo, Valentina Nascimento; Guimarães, Bruna Martins; Schuler, Marie; Pimenta, Vanessa; Rollin, Patrick; Tatibouët, Arnaud; de Oliveira, Ronaldo Nascimento

    2016-12-21

    Glycerol carbonate and tri-O-acetyl-D-glucal were used for the synthesis of glycero-functionalized carbohydrates. Ferrier reaction between the two partners afforded the O-glucoside in 84% yield. Spontaneous crystallization yielded 28% of a pure diastereoisomer with the S configuration as determined by X-ray crystallography. Then, the azido-glycerosugar was prepared in two steps: ring opening of the cyclic carbonate with sodium azide and per-acetylation with an excellent yield of 94%. A library of glycoconjugates were prepared using a 1,3-dipolar cycloaddition in yields ranging from 64 to 99%. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. 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.

  16. 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)

  17. Development of methods for cryopreservation of rooster sperm from the endangered breed "Gallina Valenciana de Chulilla" using low glycerol concentrations.

    Science.gov (United States)

    Blanch, E; Tomás, C; Casares, L; Gómez, E A; Sansano, S; Giménez, I; Mocé, E

    2014-06-01

    Glycerol (11%; v:v) is the cryoprotectant most often used for the cryopreservation of rooster sperm. However, chicken breeds differ in the resistance of their sperm to the cryopreservation process and endangered or local breeds usually present low fertilizing ability when conventional sperm cryopreservation protocols are used. The objective of this study was to optimize the protocol for the cryopreservation of the sperm from the endangered breed "Gallina Valenciana de Chulilla". For this purpose, 10 pools of semen from 43 roosters of this breed were cryopreserved using 8%, 7%, 6%, or 4% glycerol, and the sperm quality was determined immediately after thawing and in the insemination doses. Lohmann Brown Classic laying hens (n = 40) were used for the insemination trials. The sperm quality after cryopreservation progressively decreased as the glycerol concentration was reduced (P roosters frozen using 4% glycerol exhibited lower sperm quality but similar fertilizing ability compared with samples processed using higher glycerol concentrations. These results may provide useful information for developing cryopreservation protocols for other breeds. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. 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.

  19. Tensile and Water Absorption Properties of Biodegradable Composites Derived from Cassava Skin/ Polyvinyl Alcohol with Glycerol as Plasticizer

    International Nuclear Information System (INIS)

    Dayangku Intan Munthoub; Wan Aizan Wan Abdul Rahman

    2011-01-01

    Natural organic and abundant resources biopolymers received more attention due to their low cost, availability and degradability after usage. Cassava skin was used as natural fillers to the polyvinyl alcohol (PVA). Cassava skin/ poly vinyl alcohol blends were compounded using melt extrusion twin screw extruder and test samples were prepared using the compression method. Various ratios of cassava skin and glycerol were investigated to identify suitable composition based on the water absorption and tensile properties. The water absorption of the cassava skins/ PVA samples increased at higher composition of cassava skin due to their hydrophilic properties but decrease with glycerol content. The strength of the cassava skins/ PVA samples increased with the higher composition of cassava skin up to 70 wt % while gradually decreased with the increasing composition of glycerol. The Young modulus increased with glycerol content but decreased with fibre loading up to 70 wt %. Elongation at break decreased with fibre loading and glycerol up to 70 wt % and 30 phr, respectively. (author)

  20. Biosynthesis of Citric Acid from Glycerol by Acetate Mutants of Yarrowia lipolytica in Fed-Batch Fermentation

    Directory of Open Access Journals (Sweden)

    Anita Rywińska

    2009-01-01

    Full Text Available Pure and crude glycerol from biodiesel production have been used as substrates for citric acid production by acetate-negative mutants of Yarrowia lipolytica in fed-batch fermentation. Both the final concentration and the yield of the product were the highest when Y. lipolytica Wratislavia AWG7 strain was used in the culture with pure or crude glycerol. With a medium containing 200 g/L of glycerol, production reached a maximum of citric acid of 139 g/L after 120 h. This high yield of the product (up to 0.69 g of citric acid per gram of glycerol consumed was achieved with both pure and crude glycerol. Lower yield of citric acid in the culture with Y. lipolytica Wratislavia K1 strain (about 0.45 g/g resulted from increased erythritol concentrations (up to 40 g/L, accumulated simultaneously with the citric acid. The concentration of isocitric acid, a by-product in this fermentation, was very low, in the range from 2.6 to 4.6 g/L.

  1. Improvement of ethanol yield from glycerol via conversion of pyruvate to ethanol in metabolically engineered Saccharomyces cerevisiae.

    Science.gov (United States)

    Yu, Kyung Ok; Jung, Ju; Ramzi, Ahmad Bazli; Kim, Seung Wook; Park, Chulhwan; Han, Sung Ok

    2012-02-01

    The conversion of low-priced glycerol to higher value products has been proposed as a way to improve the economic viability of the biofuels industry. In a previous study, the conversion of glycerol to ethanol in a metabolically engineered strain of Saccharomyces cerevisiae was accomplished by minimizing the synthesis of glycerol, the main by-product in ethanol fermentation processing. To further improve ethanol production, overexpression of the native genes involved in conversion of pyruvate to ethanol in S. cerevisiae was successfully accomplished. The overexpression of an alcohol dehydrogenase (adh1) and a pyruvate decarboxylase (pdc1) caused an increase in growth rate and glycerol consumption under fermentative conditions, which led to a slight increase of the final ethanol yield. The overall expression of the adh1 and pdc1 genes in the modified strains, combined with the lack of the fps1 and gpd2 genes, resulted in a 1.4-fold increase (about 5.4 g/L ethanol produced) in fps1Δgpd2Δ (pGcyaDak, pGupCas) (about 4.0 g/L ethanol produced). In summary, it is possible to improve the ethanol yield by overexpression of the genes involved in the conversion of pyruvate to ethanol in engineered S. cerevisiae using glycerol as substrate.

  2. Enterobacter sp. LU1 as a novel succinic acid producer - co-utilization of glycerol and lactose.

    Science.gov (United States)

    Podleśny, Marcin; Jarocki, Piotr; Wyrostek, Jakub; Czernecki, Tomasz; Kucharska, Jagoda; Nowak, Anna; Targoński, Zdzisław

    2017-03-01

    Succinic acid is an important C4-building chemical platform for many applications. A novel succinic acid-producing bacterial strain was isolated from goat rumen. Phylogenetic analysis based on the 16S rRNA sequence and physiological analysis indicated that the strain belongs to the genus Enterobacter. This is the first report of a wild bacterial strain from the genus Enterobacter that is capable of efficient succinic acid production. Co-fermentation of glycerol and lactose significantly improved glycerol utilization under anaerobic conditions, debottlenecking the utilization pathway of this valuable biodiesel waste product. Succinic acid production reached 35 g l -1 when Enterobacter sp. LU1 was cultured in medium containing 50 g l -1 of glycerol and 25 g l -1 of lactose as carbon sources. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  3. Requirements of glycerol and fatty acid for triglyceride synthesis and ketogenesis by hepatocytes from normal and triiodothyronine-treated rats

    International Nuclear Information System (INIS)

    Olubadewo, J.O.; Heimberg, M.

    1985-01-01

    Hepatocytes from T3-treated rats synthesized less triglyceride and more ketone bodies from [1- 14 C]oleate at all concentrations from 0-2 mM, than did hepatocytes from euthyroid animals; addition of 1.0 mM glycerol increased triglyceride synthesis and reduced ketogenesis in hepatocytes from T3-treated rats to the rates observed in euthyroid hepatocytes in the absence of added glycerol. Glycerol did not alter triglyceride synthesis, but reduced ketogenesis genesis by euthyroid hepatocytes. It is probable from these and other data that, in the hyperthyroid rat, glycero-3-P, and not fatty acid, is rate limiting for synthesis of triglyceride, and, secondarily for reducing rates of ketogenesis in the hepatocyte

  4. Radioprotective action of glycerol and cysteamine on inactivation and mutagenesis in Salmonella tester strains after γ- and heavy ion irradiation

    International Nuclear Information System (INIS)

    Basha, S.G.; Krasavin, E.A.; Kozubek, S.

    1992-01-01

    Inactivation and mutagenesis were studied in Salmonella tester strains after γ-irradiation and after heavy ion irradiation in the presence of glycerol and cysteamine. Ions from deuteron to carbon with residual energies of 2-9 MeV/n were used. Cell sensitivity slightly increased with LET before decreasing. In the presence of glycerol the maximum was shifted to higher values of LET. The radioprotective effect of glycerol for cell killing diminished gradually with increasing LET from 2.0 for γ-radiation to 1.1 for carbon ions. Mutagenic effectiveness increased slightly for deuterium and helium ions. The radioprotective effect of cysteamine on mutagenesis was found to be very small in the case of γ-radiation for the three strains examined. (author). 20 refs.; 4 figs.; 5 tabs

  5. Effect of urea and glycerol on the adsorption of ribonuclease A at the air-water interface.

    Science.gov (United States)

    Hüsecken, Anne K; Evers, Florian; Czeslik, Claus; Tolan, Metin

    2010-08-17

    This study reports on the influence of nonionic cosolvents on the interfacial structure of ribonuclease A (RNase) adsorbed at the air-water interface. We applied X-ray reflectometry to obtain detailed volume fraction profiles of the adsorbed layers and to follow the effect of glycerol and urea on the adsorbate structure as a function of cosolvent concentration. Under all conditions studied, the adsorbed RNase layer maintains its compact shape, and the adsorbed RNase molecules adopt a flat-on orientation at the interface. Both kosmotropic glycerol and chaotropic urea exert profound effects on the adsorbate: The surface excess decreases linearly with glycerol content and is also reduced at low urea concentration. However, at high urea concentration, parts of the adsorbed layer are dehydrated and become exposed to air. The electron density and volume fraction profiles of the adsorbed protein provide clear evidence that these effects are ruled by different mechanisms.

  6. Effect of natamycin, nisin and glycerol on the physicochemical properties, roughness and hydrophobicity of tapioca starch edible films.

    Science.gov (United States)

    Ollé Resa, Carolina P; Jagus, Rosa J; Gerschenson, Lía N

    2014-07-01

    In this paper, films based on tapioca starch and containing nisin, natamycin and glycerol were characterized in relation to their physicochemical properties, roughness and hydrophobicity. The content of glycerol affected the mechanical properties of the films studied and the roughness and it was observed an increase in WVP with the increase in glycerol content. The addition of antimicrobials affected the mechanical properties, being nisin the one that produced the greater decrease in the Young modulus. The color was highly affected by the joint presence of natamycin and nisin, which increased the yellow index. The contact angle increased with antimicrobial addition indicating a decrease in hydrophilicity. Nisin also affected the roughness of the films. Water vapor permeability was slightly reduced by the presence of natamycin. It was observed that water vapor permeability and contact angle were correlated with the roughness of the films. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. A high glycerol-containing leave-on scalp care treatment to improve dandruff.

    Science.gov (United States)

    Harding, Clive R; Matheson, Jane R; Hoptroff, Michael; Jones, David A; Luo, Yanjun; Baines, Fiona L; Luo, Shengjun

    2014-01-01

    Dandruff is a common cosmetic condition associated with flaky scalp skin and pruritus. It is generally treated with regular use of antifungal-based shampoos. Research into factors underlying the characteristic skin lesions has revealed perturbations in epidermal differentiation and a dramatic deterioration in the associated process of stratum corneum (SC) maturation. These observations suggest that directly addressing the quality of the SC could have a scalp benefit. In this study, the authors investigated the efficacy of a moisturising leave-on lotion (LOL) containing a high concentration of glycerol (10%) and other known skin benefit agents (saturated fatty acid and sunflower seed oil) to reduce dandruff over an 8-week treatment period with 3 applications per week. Results of expert visual grading and biophysical measurements of SC parameters (transepidermal water loss and hydration) revealed a significant reduction in the dandruffcondition over this period, with significant improvement in both SC water barrier function and hydration. These scalp skin benefits were maintained for up to a week following cessation of the treatment. This study indicates that use of a glycerol-rich substantive LOL, designed to directly improve the quality of the SC barrier can have a significant impact on the dandruff condition.

  8. Poly(glycerol adipate) - indomethacin drug conjugates - synthesis and in vitro characterization.

    Science.gov (United States)

    Wersig, T; Hacker, M C; Kressler, J; Mäder, K

    2017-10-05

    The linear biodegradable polyester poly(glycerol adipate) (PGA) was synthesized via enzymatic polycondensation using lipase B from Candida antarctica (CAL-B). Every monomer unit of PGA possesses a pendant hydroxyl group which is responsible for the hydrophilic character and moisture swelling. These OH groups were esterified to different degrees with the anti-inflammatory drug indomethacin in order to create a prodrug with a pH-sensitive linker for modified drug release. The structure of the conjugates was determined via ATR FT-IR spectroscopy, NMR spectroscopy, GPC and UV/VIS spectroscopy. The physical properties of polymers with different drug load were investigated using DSC, contact angle measurements and oscillatory rheology. Drug release was monitored over one month in vitro. A very slow, but continuous release was observed in PBS. Slightly acidic conditions and lipase activity are accelerating the indomethacin release. Therefore, poly(glycerol adipate) - indomethacin conjugates are promising prodrugs for the local sustained release of indomethacin. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Experimental assessment of toxic phytochemicals in Jatropha curcas: oil, cake, bio-diesel and glycerol.

    Science.gov (United States)

    Pradhan, Subhalaxmi; Naik, S N; Khan, M Ashhar I; Sahoo, P K

    2012-02-01

    Jatropha curcas seed is a rich source of oil; however, it can not be utilised for nutritional purposes due to presence of toxic and anti-nutritive compounds. The main objective of the present study was to quantify the toxic phytochemicals present in Indian J. curcas (oil, cake, bio-diesel and glycerol). The amount of phorbol esters is greater in solvent extracted oil (2.8 g kg⁻¹) than in expeller oil (2.1 g kg⁻¹). Liquid chromatography-mass spectroscopy analysis of the purified compound from an active extract of oil confirmed the presence of phorbol esters. Similarly, the phorbol esters content is greater in solvent extracted cake (1.1 g kg⁻¹) than in cake after being expelled (0.8 g kg⁻¹). The phytate and trypsin inhibitory activity of the cake was found to be 98 g kg⁻¹ and 8347 TIU g⁻¹ of cake, respectively. Identification of curcin was achieved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the concentration of curcin was 0.95 g L⁻¹ of crude concentrate obtained from cake. Higher amounts of phorbol esters are present in oil than cake but bio-diesel and glycerol are free of phorbol esters. The other anti-nutritional components such as trypsin inhibitors, phytates and curcin are present in cake, so the cake should be detoxified before being used for animal feed. Copyright © 2011 Society of Chemical Industry.

  10. Enzymatic primer-extension with glycerol-nucleoside triphosphates on DNA templates.

    Directory of Open Access Journals (Sweden)

    Jesse J Chen

    Full Text Available BACKGROUND: Glycerol nucleic acid (GNA has an acyclic phosphoglycerol backbone repeat-unit, but forms stable duplexes based on Watson-Crick base-pairing. Because of its structural simplicity, GNA is of particular interest with respect to the possibility of evolving functional polymers by in vitro selection. Template-dependent GNA synthesis is essential to any GNA-based selection system. PRINCIPAL FINDINGS: In this study, we investigated the ability of various DNA polymerases to use glycerol-nucleoside triphosphates (gNTPs as substrates for GNA synthesis on DNA templates. Therminator DNA polymerase catalyzes quantitative primer-extension by the incorporation of two glyceronucleotides, with much less efficient extension up to five glyceronucleotides. Steady-state kinetic experiments suggested that GNA synthesis by Therminator was affected by both decreased catalytic rates and weakened substrate binding, especially for pyrimidines. In an attempt to improve pyrimidine incorporation by providing additional stacking interactions, we synthesized two new gNTP analogs with 5-propynyl substituted pyrimidine nucleobases. This led to more efficient incorporation of gC, but not gT. CONCLUSIONS: We suggest that directed evolution of Therminator might lead to mutants with improved substrate binding and catalytic efficiency.

  11. Vapour phase dehydration of glycerol to acrolein over tungstated zirconia catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Rao Ginjupalli, Srinivasa; Mugawar, Sowmya; Rajan, Pethan N.; Kumar Balla, Putra; Chary Komandur, V.R., E-mail: kvrchary@iict.res.in

    2014-08-01

    Tetragonal (TZ) and monoclinic (MZ) polymorphs of zirconia supports were synthesised by sol–gel method followed by variation of the calcination temperature. Tungstated (10 wt% WO{sub 3}) supported on the zirconia polymorphs were prepared by impregnation method by using ammonium metatungstate precursor. The physico-chemical properties of the calcined catalysts were characterised by X-ray diffraction, UV–vis diffused reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), surface area and pore size distribution measurements to gain insight into the effect of morphology of the catalyst textural properties, and structure. The surface acidic properties have been determined by NH{sub 3} TPD method and also with FT-IR spectra of pyridine adsorption. Vapour phase dehydration of glycerol to acrolein was employed to investigate the catalytic functionalities. Glycerol conversion and acrolein selectivity was mainly dependent on the fraction of moderate acid sites with majority of them are due to Brønsted acidic sites. Monoclinic zirconia based catalysts have shown the highest activity and acrolein selectivity compared to the corresponding tetragonal zirconia catalysts.

  12. A tailored catalyst for the sustainable conversion of glycerol to acrolein: mechanistic aspect of sequential dehydration.

    Science.gov (United States)

    Yun, Danim; Kim, Tae Yong; Park, Dae Sung; Yun, Yang Sik; Han, Jeong Woo; Yi, Jongheop

    2014-08-01

    Developing a catalyst to resolve deactivation caused from coke is a primary challenge in the dehydration of glycerol to acrolein. An open-macropore-structured and Brønsted-acidic catalyst (Marigold-like silica functionalized with sulfonic acid groups, MS-FS) was synthesized for the stable and selective production of acrolein from glycerol. A high acrolein yield of 73% was achieved and maintained for 50 h in the presence of the MS-FS catalyst. The hierarchical structure of the catalyst with macropores was found to have an important effect on the stability of the catalyst because coke polymerization and pore blocking caused by coke deposition were inhibited. In addition, the behavior of 3-hydroxypropionaldehyde (3-HPA) during the sequential dehydration was studied using density functional theory (DFT) calculations because 3-HPA conversion is one of the main causes for coke formation. We found that the easily reproducible Brønsted acid sites in MS-FS permit the selective and stable production of acrolein. This is because the reactive intermediate (3-HPA) is readily adsorbed on the regenerated acid sites, which is essential for the selective production of acrolein during the sequential dehydration. The regeneration ability of the acid sites is related not only to the selective production of acrolein but also to the retardation of catalyst deactivation by suppressing the formation of coke precursors originating from 3-HPA degradation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. 1-alkenyl-2-acyl glycerol is an intermediate in myocardial plasmenylcholine biosynthesis

    International Nuclear Information System (INIS)

    Ford, D.; Gross, R.

    1987-01-01

    The present study was undertaken to identify the metabolic pathway(s) responsible for myocardial plasmenylcholine biosynthesis. Rabbit myocardium contained .46 +/- .09 nmol/g wet wight of 1-alkenyl-2-acyl glycerol (AAG) which predominantly consisted of 16:0 molecular species at the sn-1 position. Incubation of rabbit myocardial microsomes (RMM) with [ 14 C]CDP-choline ( 14 C-CDPC) resulted in the rapid incorporation of radiolabeled choline into the choline glycerophospholipid pool. RP-HPLC separation of molecular species demonstrated that nearly equal amounts of radiolabel were incorporated into plasmenylcholine and phosphatidylcholine subclasses despite the fact that RMM contained 21 times the mass of diacyl glycerol as compared to AAG. RMM incorporation of 14 C-CDPC into choline glycerophospholipids was substantially greater than incorporation of [ 14 C] phosphorylcholine or [ 14 C] choline. RMM incorporation of 14 C-CDPC into plasmalogen molecular species was stimulated two fold by 500 μM CMP. Taken together, these results demonstrate that rabbit myocardium contains substantial quantities of AAG and that endogenous AAG is an efficient precursor of myocardial plasmenylcholine

  14. A study of a co-processed dry binder composed of microcrystalline cellulose and glycerol monostearate.

    Science.gov (United States)

    Mužíková, Jitka; Muchová, Sandra

    2012-10-01

    The paper studies the co-processed dry binder LubriToseTM MCC from the viewpoint of energy evaluation of the compression process, strength and disintegration time of tablets. The results were compared with the identical evaluation of physical mixtures of microcrystalline cellulose with several types of lubricants. LubriTose MCC showed the lowest value of energy for friction, the highest value of energy accumulated by the tablet, and the highest plasticity of all tableting materials under study. There were no marked differences in the values of the energy of decompression. The tensile strength of tablets from LubriTose MCC was lower than in those from the mixture of Vivapur® 12 and glycerol monostearate, in the compression forces of 4 and 5 kN it was comparable with the tensile strength of tablets from Vivapur 12 with Poloxamer 407. Disintegration time of tablets from LubriTose MCC was shorter than that of those from Vivapur 12 with glycerol monostearate at the compression force of 3 kN, in the case of the compression forces of 4 and 5 kN no statistically significant difference was found between the values of these tableting materials.

  15. Modeling and Parameter Identification Involving 3-Hydroxypropionaldehyde Inhibitory Effects in Glycerol Continuous Fermentation

    Directory of Open Access Journals (Sweden)

    Zhaohua Gong

    2012-01-01

    Full Text Available Mathematical modeling and parameter estimation are critical steps in the optimization of biotechnological processes. In the 1,3-propanediol (1,3-PD production by glycerol fermentation process under anaerobic conditions, 3-hydroxypropionaldehyde (3-HPA accumulation would arouse an irreversible cessation of the fermentation process. Considering 3-HPA inhibitions to cells growth and to activities of enzymes, we propose a novel mathematical model to describe glycerol continuous cultures. Some properties of the above model are discussed. On the basis of the concentrations of extracellular substances, a parameter identification model is established to determine the kinetic parameters in the presented system. Through the penalty function technique combined with an extension of the state space method, an improved genetic algorithm is then constructed to solve the parameter identification model. An illustrative numerical example shows the appropriateness of the proposed model and the validity of optimization algorithm. Since it is difficult to measure the concentrations of intracellular substances, a quantitative robustness analysis method is given to infer whether the model is plausible for the intracellular substances. Numerical results show that the proposed model is of good robustness.

  16. Biodegradable blends of starch/polyvinyl alcohol/glycerol: multivariate analysis of the mechanical properties

    Directory of Open Access Journals (Sweden)

    Juliano Zanela

    Full Text Available Abstract The aim of the work was to study the mechanical properties of extruded starch/polyvinyl alcohol (PVA/glycerol biodegradable blends using multivariate analysis. The blends were produced as cylindrical strands by extrusion using PVAs with different hydrolysis degrees and viscosities, at two extrusion temperature profiles (90/170/170/170/170 °C and 90/170/200/200/200 °C and three conditioning relative humidities of the samples (33, 53, and 75%. The mechanical properties showed a great variability according to PVA type, as well as the extrusion temperature profile and the conditioning relative humidity; the tensile strength ranged from 0.42 to 5.40 MPa, elongation at break ranged from 10 to 404% and Young’s modulus ranged from 0.93 to 13.81 MPa. The multivariate analysis was a useful methodology to study the mechanical properties behavior of starch/PVA/glycerol blends, and it can be used as an exploratory technique to select of the more suitable PVA type and extrusion temperature to produce biodegradable materials.

  17. Gluconeogenesis in Leishmania mexicana: contribution of glycerol kinase, phosphoenolpyruvate carboxykinase, and pyruvate phosphate dikinase.

    Science.gov (United States)

    Rodriguez-Contreras, Dayana; Hamilton, Nicklas

    2014-11-21

    Gluconeogenesis is an active pathway in Leishmania amastigotes and is essential for their survival within the mammalian cells. However, our knowledge about this pathway in trypanosomatids is very limited. We investigated the role of glycerol kinase (GK), phosphoenolpyruvate carboxykinase (PEPCK), and pyruvate phosphate dikinase (PPDK) in gluconeogenesis by generating the respective Leishmania mexicana Δgk, Δpepck, and Δppdk null mutants. Our results demonstrated that indeed GK, PEPCK, and PPDK are key players in the gluconeogenesis pathway in Leishmania, although stage-specific differences in their contribution to this pathway were found. GK participates in the entry of glycerol in promastigotes and amastigotes; PEPCK participates in the entry of aspartate in promastigotes, and PPDK is involved in the entry of alanine in amastigotes. Furthermore, the majority of alanine enters into the pathway via decarboxylation of pyruvate in promastigotes, whereas pathway redundancy is suggested for the entry of aspartate in amastigotes. Interestingly, we also found that l-lactate, an abundant glucogenic precursor in mammals, was used by Leishmania amastigotes to synthesize mannogen, entering the pathway through PPDK. On the basis of these new results, we propose a revision in the current model of gluconeogenesis in Leishmania, emphasizing the differences between amastigotes and promastigotes. This work underlines the importance of studying the trypanosomatid intracellular life cycle stages to gain a better understanding of the pathologies caused in humans. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. Determination of activation energy for animal fat and crude glycerol using thermogravimetric analysis

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Crhristoph [University of Hannover, Hannover (Germany); Mortari, Daniela; Avila, Ivonete; Santos, Antonio Moreira dos; Silva, Mario Lucio Cristovam; Crnkovic, Paula Manoel [University of Sao Paulo, Sao Carlos, SP (Brazil)], e-mails: iavila@sc.usp.br, asantos@sc.usp.br, paulam@sc.usp.br

    2010-07-01

    The present study deals with the determination of the activation energy of animal fat and crude glycerol from a biodiesel production plant. The activation energies were investigated by thermogravimetric analysis in the temperature range of {delta}T = 25-600 deg C. The transient experiments were run for every sample (10 mg) at five different heating rates (2.5, 5.0, 10.0, 20.0 and 30.0 deg C/min) in atmosphere of synthetic air. It is possible to establish a direct relation between the activation energy and the ignition delay, which characterizes the combustion quality of a fuel. The activation energy could be determined as a function of the conversion degree and the temperature by the isoconversional model free kinetics. Four distinct phases were found for each sample and one of these phases was identified as low-temperature oxidation (LTO). As this region is responsible for the first vaporization of the fuel, the activation energies were determined for this special region along the whole conversion range (0 - 100 %). The following mean values could be determined: animal fat = 108.87 +- 52.28 kJ/mol, and crude glycerol = 65.37+- 13.17 kJ/mol. From these data, it was possible to conclude that animal fat is the most complex sample between the ones studied in this work (author)

  19. CO2 Absorption from Biogas by Glycerol: Conducted in Semi-Batch Bubble Column

    Science.gov (United States)

    puji lestari, Pratiwi; Mindaryani, Aswati; Wirawan, S. K.

    2018-03-01

    Biogas is a renewable energy source that has been developed recently. The main contents of Biogas itself are Methane and carbon dioxide (CO2) where Methane is the main component of biogas with CO2 as the highest impurities. The quality of biogas depends on the CO2 content, the lower CO2 levels, the higher biogas quality. Absorption is one of the methods to reduce CO2 level. The selections of absorbent and appropriate operating parameters are important factors in the CO2 absorption from biogas. This study aimed to find out the design parameters for CO2 absorption using glycerol that represented by the overall mass transfer coefficient (KLa) and Henry’s constant (H). This study was conducted in semi-batch bubble column. Mixed gas was contacted with glycerol in a bubble column. The concentration of CO2 in the feed gas inlet and outlet columns were analysed by Gas Chromatograph. The variables observed in this study were superficial gas velocity and temperatures. The results showed that higher superficial gas velocity and lower temperature increased the rate of absorption process and the amount of CO2 absorbed.

  20. Thermal, mechanical, and moisture absorption properties of egg white protein bioplastics with natural rubber and glycerol.

    Science.gov (United States)

    Jones, Alexander; Zeller, Mark Ashton; Sharma, Suraj

    2013-07-03

    Petroleum-based plastics have many drawbacks: the large amount of energy required to produce the plastic, the waste generated as a result of plastic production, and the accumulation of waste due to slow degradation rate. It is because of these negative attributes of conventional plastic use that attention is being focused on environmentally friendly plastics from alternative sources. Albumin protein provides one possible source of raw material, with inherent antimicrobial properties that may make it suitable for medical applications. We conducted this study to investigate the various bioplastic properties of the albumin with the use of three plasticizers - water, glycerol, and natural rubber latex. Based on results, 75:25 albumin-water, 75:25 albumin-glycerol, and 80:20 albumin-natural rubber were the best blending ratios for each plasticizer for a subsequent time study to determine water stability, with the 80:20 albumin-natural rubber blend ratio having possessed the best thermal, tensile, and viscoelastic properties overall.

  1. Vapour phase dehydration of glycerol to acrolein over tungstated zirconia catalysts

    Science.gov (United States)

    Rao Ginjupalli, Srinivasa; Mugawar, Sowmya; Rajan N., Pethan; Kumar Balla, Putra; Chary Komandur, V. R.

    2014-08-01

    Tetragonal (TZ) and monoclinic (MZ) polymorphs of zirconia supports were synthesised by sol-gel method followed by variation of the calcination temperature. Tungstated (10 wt% WO3) supported on the zirconia polymorphs were prepared by impregnation method by using ammonium metatungstate precursor. The physico-chemical properties of the calcined catalysts were characterised by X-ray diffraction, UV-vis diffused reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), surface area and pore size distribution measurements to gain insight into the effect of morphology of the catalyst textural properties, and structure. The surface acidic properties have been determined by NH3 TPD method and also with FT-IR spectra of pyridine adsorption. Vapour phase dehydration of glycerol to acrolein was employed to investigate the catalytic functionalities. Glycerol conversion and acrolein selectivity was mainly dependent on the fraction of moderate acid sites with majority of them are due to Brønsted acidic sites. Monoclinic zirconia based catalysts have shown the highest activity and acrolein selectivity compared to the corresponding tetragonal zirconia catalysts.

  2. Vapour phase dehydration of glycerol to acrolein over tungstated zirconia catalysts

    International Nuclear Information System (INIS)

    Rao Ginjupalli, Srinivasa; Mugawar, Sowmya; Rajan, Pethan N.; Kumar Balla, Putra; Chary Komandur, V.R.

    2014-01-01

    Tetragonal (TZ) and monoclinic (MZ) polymorphs of zirconia supports were synthesised by sol–gel method followed by variation of the calcination temperature. Tungstated (10 wt% WO 3 ) supported on the zirconia polymorphs were prepared by impregnation method by using ammonium metatungstate precursor. The physico-chemical properties of the calcined catalysts were characterised by X-ray diffraction, UV–vis diffused reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), surface area and pore size distribution measurements to gain insight into the effect of morphology of the catalyst textural properties, and structure. The surface acidic properties have been determined by NH 3 TPD method and also with FT-IR spectra of pyridine adsorption. Vapour phase dehydration of glycerol to acrolein was employed to investigate the catalytic functionalities. Glycerol conversion and acrolein selectivity was mainly dependent on the fraction of moderate acid sites with majority of them are due to Brønsted acidic sites. Monoclinic zirconia based catalysts have shown the highest activity and acrolein selectivity compared to the corresponding tetragonal zirconia catalysts.

  3. Gas-phase Dehydration of Glycerol over Supported Silicotungstic Acids Catalysts

    International Nuclear Information System (INIS)

    Kim, Yong Tae; Park, Eun Duck; Jung, Kwang Deog

    2010-01-01

    The gas-phase dehydration of glycerol to acrolein was carried out over 10 wt % HSiW catalysts supported on different supports, viz. γ-Al 2 O 3 , SiO 2 -Al 2 O 3 , TiO 2 , ZrO 2 , SiO 2 , AC, CeO 2 and MgO. The same reaction was also conducted over each support without HSiW for comparison. Several characterization techniques, N 2 -physisorption, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), the temperature-programmed desorption of ammonia (NH 3 - TPD), temperature-programmed oxidation (TPO) with mass spectroscopy and CHNS analysis were employed to characterize the catalysts. The glycerol conversion generally increased with increasing amount of acid sites. Ceria showed the highest 1-hydroxyacetone selectivity at 315 .deg. C among the various metal oxides. The supported HSiW catalyst showed superior catalytic activity to that of the corresponding support. Among the supported HSiW catalysts, HSiW/ZrO 2 and HSiW/SiO 2 -Al 2 O 3 showed the highest acrolein selectivity. In the case of HSiW/ZrO 2 , the initial catalytic activity was recovered after the removal of the accumulated carbon species at 550 .deg. C in the presence of oxygen

  4. Diversity of Lactobacillus reuteri Strains in Converting Glycerol into 3-Hydroxypropionic Acid.

    Science.gov (United States)

    Burgé, G; Saulou-Bérion, C; Moussa, M; Pollet, B; Flourat, A; Allais, F; Athès, V; Spinnler, H E

    2015-10-01

    The present study aims at comparing the performances of three Lactobacillus reuteri strains (DSM 20016, DSM 17938, and ATCC 53608) in producing 3-hydroxypropionic acid (3-HP) from glycerol and at exploring inhibition phenomena during this bioconversion. Differences were highlighted between the three strains in terms of 3-HP production yield, kinetics of substrate consumption, and metabolite production. With a maximal productivity in non-optimal conditions (free pH) around 2 g.L(-1).h(-1) of 3-HP and 4 g.L(-1).h(-1) of 3-hydroxypropionaldehyde (3-HPA) depending on the strain, this study confirmed the potential of L. reuteri for the biotechnological production of 3-HP. Moreover, the molar ratios of 3-HP to 1,3-propanediol (1,3-PDO) obtained for the three strains (comprised between 1.25 and 1.65) showed systematically a higher 3-HP production. From these results, the DSM 17938 strain appeared to be the most promising strain. The impact of glycerol bioconversion on the bacteria's physiological state (a decrease of around 40 % in DSM 17938 cells showing an enzymatic activity after 3 h) and survival (total loss of cultivability after 2 or 3 h depending on the strains) was revealed and discussed. The effect of each metabolite on L. reuteri DSM 17938 was further investigated, displaying a drastic inhibition caused by 3-HPA, while 3-HP induced lower impact and only at acidic pH.

  5. Lithium modified zeolite synthesis for conversion of biodiesel-derived glycerol to polyglycerol

    Energy Technology Data Exchange (ETDEWEB)

    Ayoub, Muhammad, E-mail: muhammad.ayoub@petronas.com.my [Department of Chemical Engineering, Universiti Teknologi PETRONAS, 31750, Tronoh, Perak, Malaysia and School of Chemical Engineering, Universiti Sains Malaysia, 43000, Pinang (Malaysia); Abdullah, Ahmad Zuhairi, E-mail: chzuhairi@usm.my [School of Chemical Engineering, Universiti Sains Malaysia, 43000, Pinang (Malaysia); Inayat, Abrar, E-mail: abrar.inayat@petronas.com.my [Department of Chemical Engineering, Universiti Teknologi PETRONAS, 31750, Tronoh, Perak (Malaysia)

    2014-10-24

    Basic zeolite has received significant attention in the catalysis community. These zeolites modified with alkaline are the potential replacement for existing zeolite catalysts due to its unique features with added advantages. The present paper covers the preparation of lithium modified zeolite Y (Li-ZeY) and its activity for solvent free conversion of biodiesel-derived glycerol to polyglycerol via etherification process. The modified zeolite was well characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and Nitrogen Adsorption. The SEM images showed that there was no change in morphology of modified zeolite structure after lithium modification. XRD patterns showed that the structure of zeolite was sustained after lithium modification. The surface properties of parent and modified zeolite was also observed N{sub 2} adsortion-desorption technique and found some changes in surface area and pore size. In addition, the basic strength of prepared materials was measured by Hammet indicators and found that basic strength of Li-ZeY was highly improved. This modified zeolite was found highly thermal stable and active heterogamous basic catalyst for conversion of solvent free glycerol to polyglycerol. This reaction was conducted at different temperatures and 260 °C was found most active temperature for this process for reaction time from 6 to 12 h over this basic catalyst in the absence of solvent.

  6. Optimization of prodigiosin production by Serratia marcescens using crude glycerol and enhancing production using gamma radiation

    Directory of Open Access Journals (Sweden)

    Nora M. Elkenawy

    2017-03-01

    Full Text Available Prodigiosin is a red pigment produced by Serratia marcescens. Prodigiosin is regarded as a promising drug owing to its reported characteristics of possessing anti-microbial, anti-cancer, and immunosuppressive activity. A factorial design was applied to generate a set of 32 experimental combinations to study the optimal conditions for pigment production using crude glycerol obtained from local biodiesel facility as carbon source for the growth of Serratia marcescens. The maximum production (870 unit/cell was achieved at 22 °C, at pH 9 with the addition of 1% (w/v peptone and 109 cell/ml inoculum size after 6 days of incubation. Gamma radiation at dose 200 Gy was capable of doubling the production of the pigment using the optimized conditions and manipulating production temperature. Our results indicate that we have designed an economic medium supporting enhanced Serratia marcescens MN5 prodigiosin production giving an added value for crude glycerol obtained from biodiesel industry.

  7. New magnetic nanobiocomposite based in galactomannan/glycerol and superparamagnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Souza, N.D.G.; Freire, R.M.; Cunha, A.P. [Grupo de Química de Materiais Avançados (GQMAT), Departamento de Química Analítica e Físico-Química, Universidade Federal do Ceará – UFC, Campus do Pici, CP 12100, CEP 60451-970 Fortaleza, CE (Brazil); Silva, M.A.S. da [LOCEM – Laboratório de Telecomunicações e Ciência e Engenharia de Materiais, Departamento de Física, Universidade Federal do Ceará, Fortaleza, CE (Brazil); Mazzetto, S.E. [Grupo de Química de Materiais Avançados (GQMAT), Departamento de Química Analítica e Físico-Química, Universidade Federal do Ceará – UFC, Campus do Pici, CP 12100, CEP 60451-970 Fortaleza, CE (Brazil); Sombra, A.S.B. [LOCEM – Laboratório de Telecomunicações e Ciência e Engenharia de Materiais, Departamento de Física, Universidade Federal do Ceará, Fortaleza, CE (Brazil); Denardin, J.C. [Departamento de Física, Universidad de Santiago de Chile, USACH, Av. Ecuador 3493, Santiago (Chile); and others

    2015-04-15

    In this study, magnetic nanobiocomposites were prepared in different proportions and produced with galactomannan (GM), magnetic nanoparticles of NiZn and glycerol (GL). The microstructure and morphology of the samples were characterized by Scanning Electron Microscopy (SEM), X-ray powder diffraction, Fourier transform infrared (FTIR) spectroscopy, Thermal analysis (TG) and Differential scanning calorimetry (DSC). The magnetic and dielectric behavior of the films was studied by Vibrating sample magnetometer (VSM) and Impedance spectroscopy. The results showed efficient incorporation of NiZn in the polymer matrix. The degradation profiles presented thermal events that were confirmed by endothermic and exothermic processes from DSC measurements. Films presented saturation magnetization (M{sub s}) range from 6 to 17 emu/g and superparamagnetic behavior. It was observed that the values of dielectric constant increased as a function of the nanoparticles concentration in the bionacomposite. Thus, this kind of biocomposite could be used as a versatile magnetic-dielectric in microwave devices. - Highlights: • Incorporation of inorganic nanoparticles in the galactomannan/glycerol polymer matrix. • All nanobiocomposites presented superparamagnetic behavior. • It can be employed as a versatile material, due to their flexible and dielectric-magnetic features.

  8. Modeling chemical kinetics of avocado oil ethanolysis catalyzed by solid glycerol-enriched calcium oxide

    International Nuclear Information System (INIS)

    Avhad, M.R.; Sánchez, M.; Bouaid, A.; Martínez, M.; Aracil, J.; Marchetti, J.M.

    2016-01-01

    Highlights: • Raw materials for biodiesel production can be obtained from the natural resources. • The glycerol-enriched CaO catalyst was tested for the ethanolysis of avocado oil. • CaO synthesized through the thermal treatment of Mytilus Galloprovincialis shells. • The ethanol-adsorption step controlled the overall ethanolysis process. • The physico-chemical properties of avocado oil and FAEEs is presented. - Abstract: The catalytic activity of glycerol-enriched calcium oxide for the alcoholysis reaction between avocado oil and ethanol was investigated. The calcium oxide was derived from Mytilus Galloprovincialis shells. This study systematically examined the influence of temperature, ethanol-to-oil molar ratio, and the catalyst amount on the variation in the concentration of triacylglycerols and biodiesel with reaction time. The interaction between the reaction variables (ethanol-to-oil molar ratio and catalyst amount), their influence on the ethanolysis process, and the optimum variables affecting the process were determined through the response surface methodology. A previously developed mathematical model was applied for the current ethanolysis process, and the model parameters were determined. The ethanolysis reaction occurred between the surface chemisorbed ethoxide ions and oil molecules in the liquid phase, while, the overall process was controlled by the ethanol-adsorption step. The physico-chemical properties of biodiesel, produced using potassium methoxide catalyst, were additionally measured.

  9. Linear equations on thermal degradation products of wood chips in alkaline glycerol

    International Nuclear Information System (INIS)

    Demirbas, Ayhan

    2004-01-01

    Wood chips of 0.3 and 2 mm depth from poplar and spruce wood samples, respectively, were degraded by using glycerol as a solvent and alkaline glycerol with and without Na 2 CO 3 and NaOH catalysts at different degradation temperatures: 440, 450, 460, 470, 480, 490 and 500 K. By products from the degradation processes of the ligno celluloses include lignin degradation products. Lignin and its degradation products have fuel values. The total degradation degree and cellulose degradation of the wood chips were determined to find the relationship, if any, between the yields of total degradation degree (YTD) and degradation temperature (T). There is a good linear relationship between YTD or the yields of cellulose degradation (YCD) and T (K). For the wood samples, the regression equations from NaOH (10%) catalytic runs for 0.3 mm x 15 mm x 15 mm chip size are: For poplar wood: (YTD=0.7250T-267.507) (YCD=0.1736T-71.707) For spruce wood: (YTD=0.2650T-105.979) (YCD=0.0707T-27.507) For Eqs., the square of the correlation coefficient (r 2 ) were 0.9841, 0.9496, 0.9839 and 0.9447, respectively

  10. Overproduction, purification, crystallization and preliminary X-ray diffraction analysis of Trypanosoma brucei gambiense glycerol kinase

    International Nuclear Information System (INIS)

    Balogun, Emmanuel Oluwadare; Inaoka, Daniel Ken; Kido, Yasutoshi; Shiba, Tomoo; Nara, Takeshi; Aoki, Takashi; Honma, Teruki; Tanaka, Akiko; Inoue, Masayuki; Matsuoka, Shigeru; Michels, Paul A. M.; Harada, Shigeharu; Kita, Kiyoshi

    2010-01-01

    Glycerol kinase from human African trypanosomes has been purified and crystallized for X-ray structure analysis. In the bloodstream forms of human trypanosomes, glycerol kinase (GK; EC 2.7.1.30) is one of the nine glycosomally compartmentalized enzymes that are essential for energy metabolism. In this study, a recombinant Trypanosoma brucei gambiense GK (rTbgGK) with an N-terminal cleavable His 6 tag was overexpressed, purified to homogeneity and crystallized by the sitting-drop vapour-diffusion method using PEG 400 as a precipitant. A complete X-ray diffraction data set to 2.75 Å resolution indicated that the crystals belonged to the orthorhombic space group P2 1 2 1 2 1 , with unit-cell parameters a = 63.84, b = 121.50, c = 154.59 Å. The presence of two rTbgGK molecules in the asymmetric unit gives a Matthews coefficient (V M ) of 2.5 Å 3 Da −1 , corresponding to 50% solvent content

  11. 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.

  12. A comprehensive energy–exergy-based assessment and parametric study of a hydrogen production process using steam glycerol reforming

    International Nuclear Information System (INIS)

    Hajjaji, Noureddine; Chahbani, Amna; Khila, Zouhour

    2014-01-01

    Various assessment tools are applied to comprehensively investigate a glycerol-to-hydrogen production system. These tools investigate the chemical reactions, design and simulate the entire hydrogen production process, study the energetic and exergetic performances and perform parametric analyses (using intuitive and design of experiment-based methods). Investigating the chemical reaction of steam glycerol reforming reveals that the optimal conditions, determined based on maximizing the hydrogen production while minimizing the methane and carbon monoxide contents and coke formation, can be achieved at a reforming temperature and a water-to-glycerol feed ratio (WGFR) of 950 K and 9, respectively. The thermal and exergetic efficiencies of the resulting process are 66.6% and 59.9%, respectively. These findings are lower than those cited in the literature and relative to other reformates (methane, ethanol and methanol). The parametric investigation indicates that the performance of the process (energetic and exergetic) could be ensured by using an appropriate and judiciously selected combination of the reactor temperature and WGFR. Based on the parametric energetic and exergetic investigation, WGFR = 6 and T = 1100 K appear to be the most accurate parameters for the entire glycerol-to-hydrogen process. For this recommend configuration, the thermal and exergetic efficiencies are 78.1% and 66.1%, respectively. - Highlights: • Energy and exergy analysis are used to assess glycerol-to-hydrogen process. • Recommended conditions for glycerol-to-hydrogen process are WGFR = 6 and T = 1100 K. • For recommend conditions, thermal and exergetic efficiencies are 78.1% and 66.1%. • Energy and exergy consideration should be included by engineers and scientists

  13. The metabolic costs of improving ethanol yield by reducing glycerol formation capacity under anaerobic conditions in Saccharomyces cerevisiae.

    Science.gov (United States)

    Pagliardini, Julien; Hubmann, Georg; Alfenore, Sandrine; Nevoigt, Elke; Bideaux, Carine; Guillouet, Stephane E

    2013-03-28

    Finely regulating the carbon flux through the glycerol pathway by regulating the expression of the rate controlling enzyme, glycerol-3-phosphate dehydrogenase (GPDH), has been a promising approach to redirect carbon from glycerol to ethanol and thereby increasing the ethanol yield in ethanol production. Here, strains engineered in the promoter of GPD1 and deleted in GPD2 were used to investigate the possibility of reducing glycerol production of Saccharomyces cerevisiae without jeopardising its ability to cope with process stress during ethanol production. For this purpose, the mutant strains TEFmut7 and TEFmut2 with different GPD1 residual expression were studied in Very High Ethanol Performance (VHEP) fed-batch process under anaerobic conditions. Both strains showed a drastic reduction of the glycerol yield by 44 and 61% while the ethanol yield improved by 2 and 7% respectively. TEFmut2 strain showing the highest ethanol yield was accompanied by a 28% reduction of the biomass yield. The modulation of the glycerol formation led to profound redox and energetic changes resulting in a reduction of the ATP yield (YATP) and a modulation of the production of organic acids (acetate, pyruvate and succinate). Those metabolic rearrangements resulted in a loss of ethanol and stress tolerance of the mutants, contrarily to what was previously observed under aerobiosis. This work demonstrates the potential of fine-tuned pathway engineering, particularly when a compromise has to be found between high product yield on one hand and acceptable growth, productivity and stress resistance on the other hand. Previous study showed that, contrarily to anaerobiosis, the resulting gain in ethanol yield was accompanied with no loss of ethanol tolerance under aerobiosis. Moreover those mutants were still able to produce up to 90 gl-1 ethanol in an anaerobic SSF process. Fine tuning metabolic strategy may then open encouraging possibilities for further developing robust strains with improved

  14. The effect of concentration of glycerol and electric current on the morphology and particle size of electrodeposited cadmium powder

    Directory of Open Access Journals (Sweden)

    S. G. Viswanath

    2013-06-01

    Full Text Available Cadmium powder was obtained by electrodeposition of cadmium from glycerol and sulphuric acid. The morphology and particle size of these powders were studied. Broken dendrites, intermingled with spongy and irregular particles were observed in the powder. Around 60% of particles were below 100 µm. XRD studies showed that particles with sizes between 212.2 and 303.2 nm were present in the powder. The apparent density of cadmium powder decreased with increase in concentration of glycerol. The stability of the powder and current efficiency were also studied

  15. Esterification of Glycerol with Acetic Acid over Highly Active and Stable Alumina-based Catalysts: A Reaction Kinetics Study

    OpenAIRE

    Rane, S. A.; Pudi, S. M.; Biswas, P.

    2016-01-01

    The catalytic activity of Cu- or Ni monometallic and Cu-Ni bimetallic (Cu/Ni ratio = 3, 1, 0.33) catalysts supported on γ-Al2O3 and SO42–/γ-Al2O3 catalysts were evaluated for esterification of glycerol. The reactions were performed in a batch reactor under reflux at standard reaction conditions: temperature 110 °C, atmospheric pressure, glycerol to acetic acid molar ratio 1:9, and catalyst loading 0.25 g. The best catalytic activity was observed over 2 M SO42–/γ-Al2O3 catalyst, which showed t...

  16. Prebiotic Peptide (Amide) Bond Synthesis Accelerated by Glycerol and Bicarbonate Under Neutral to Alkaline Dry-Down Conditions

    Science.gov (United States)

    Forsythe, J. G.; Weber, A. L.

    2017-01-01

    Past studies of prebiotic peptide bond synthesis have generally been carried out in the acidic to neutral pH range [1, 2]. Here we report a new process for peptide bond (amide) synthesis in the neutral to alkaline pH range that involves simple dry-down heating of amino acids in the presence of glycerol and bicarbonate. Glycerol was included in the reaction mixture as a solvent and to provide hydroxyl groups for possible formation of ester intermediates previously implicated in peptide bond synthesis under acidic to neutral conditions [1]. Bicarbonate was added to raise the reaction pH to 8-9.

  17. Synthesis of FAEEs from glycerol in engineered Saccharomyces cerevisiae using endogenously produced ethanol by heterologous expression of an unspecific bacterial acyltransferase.

    Science.gov (United States)

    Yu, Kyung Ok; Jung, Ju; Kim, Seung Wook; Park, Chul Hwan; Han, Sung Ok

    2012-01-01

    The high price of petroleum-based diesel fuel has led to the development of alternative fuels, such as ethanol. Saccharomyces cerevisiae was metabolically engineered to utilize glycerol as a substrate for ethanol production. For the synthesis of fatty acid ethyl esters (FAEEs) by engineered S. cerevisiae that utilize glycerol as substrate, heterologous expression of an unspecific acyltransferase from Acinetobacter baylyi with glycerol utilizing genes was established. As a result, the engineered YPH499 (pGcyaDak, pGupWs-DgaTCas) strain produced 0.24 g/L FAEEs using endogenous ethanol produced from glycerol. And this study also demonstrated the possibility of increasing FAEE production by enhancing ethanol production by minimizing the synthesis of glycerol. The overall FAEE production in strain YPH499 fps1Δ gpd2Δ (pGcyaDak, pGupWs-DgaTCas) was 2.1-fold more than in YPH499 (pGcyaDak, pGupWs-DgaTCas), with approximately 0.52 g/L FAEEs produced, while nearly 17 g/L of glycerol was consumed. These results clearly indicated that FAEEs were synthesized in engineered S. cerevisiae by esterifying exogenous fatty acids with endogenously produced ethanol from glycerol. This microbial system acts as a platform in applying metabolic engineering that allows the production of FAEEs from cheap and abundant substrates specifically glycerol through the use of endogenous bioethanol. Copyright © 2011 Wiley Periodicals, Inc.

  18. Elimination of Glycerol Production in Anaerobic Cultures of a Saccharomyces cerevisiae Strain Engineered To Use Acetic Acid as an Electron Acceptor

    NARCIS (Netherlands)

    Medina, V.G.; Almering, M.J.H.; Van Maris, A.J.A.; Pronk, J.T.

    2009-01-01

    In anaerobic cultures of wild-type Saccharomyces cerevisiae, glycerol production is essential to reoxidize NADH produced in biosynthetic processes. Consequently, glycerol is a major by-product during anaerobic production of ethanol by S. cerevisiae, the single largest fermentation process in

  19. Effects of ionizing radiation on glycerolated amniotic membranes as a substract for cultured human epithelium

    International Nuclear Information System (INIS)

    Paggiaro, Andre Oliveira

    2011-01-01

    The amniotic membrane (AM) is a biomaterial with biological properties that are beneficial to tissue repair. It has been used as a temporary coverage to threat burns and chronic wounds. Recently, it has been served as a substrate for keratinocytes culture to construct a living skin equivalent. However, MA is a biological material, and its transplantation could cause infectious disease for receptors. So, it must be preserved and sterilized before clinical use. The aim of this study was to evaluate the radiation effects on glycerol-preserved MA, considering its compatibility to support human keratinocytes culture. Four MA were stored in high concentrations of glycerol (> 85%) and half of them were radio sterilized with a dose of 25 kGy. Then, we established two groups: nonirradiated MA (MA-ni) and irradiated MA (MA-i). Both groups was deepithelialized by a standardized protocol and was investigated morphologically, immunohistochemical and ultrastructural. Subsequently human keratinocytes were cultivated immersed and in air-liquid interface on denuded surface of MA-i and MA-ni. The results were compared at 14 and 21 days of culture by light and electron microscopy. After epithelial denudation, analyses demonstrated the continuity of the basement membrane in MA-ni group, whereas in the irradiated group, there was no indication of the basement membrane’s presence on the surface of MA. The cell cultures showed that in the non-irradiated group, there was growth of a multi-layered and differentiated epithelium, with a stratum corneum’s formation in air-liquid interface. In the irradiated group, the epithelium had only two or three layer, little cell differentiation, with the same results immersed or air-liquid interface system. Glycerol-preserved MA was biocompatible with the growth of a cultivated epithelium, showing its potential as a skin substitute. Irradiation at 25 kGy cause structural damage to the tissue, making changes in basement membrane, that facilitates

  20. Computational fluid dynamic model for glycerol gasification in supercritical water in a tee junction shaped cylindrical reactor

    NARCIS (Netherlands)

    Yukananto, Riza; Pozarlik, Artur K.; Brem, Gerrit

    2018-01-01

    Gasification in supercritical water is a very promising technology to process wet biomass into a valuable gas. Providing insight of the process behavior is therefore very important. In this research a computational fluid dynamic model is developed to investigate glycerol gasification in

  1. Green acetylation of solketal and glycerol formal by heterogeneous acid catalysts to form a biodiesel fuel additive.

    Science.gov (United States)

    Dodson, Jennifer R; Leite, Thays d C M; Pontes, Nathália S; Peres Pinto, Bianca; Mota, Claudio J A

    2014-09-01

    A glut of glycerol has formed from the increased production of biodiesel, with the potential to integrate the supply chain by using glycerol additives to improve biodiesel properties. Acetylated acetals show interesting cold flow and viscosity effects. Herein, a solventless heterogeneously catalyzed process for the acetylation of both solketal and glycerol formal to new products is demonstrated. The process is optimized by studying the effect of acetylating reagent (acetic acid and acetic anhydride), reagent molar ratios, and a variety of commercial solid acid catalysts (Amberlyst-15, zeolite Beta, K-10 Montmorillonite, and niobium phosphate) on the conversion and selectivities. High conversions (72-95%) and selectivities (86-99%) to the desired products results from using acetic anhydride as the acetylation reagent and a 1:1 molar ratio with all catalysts. Overall, there is a complex interplay between the solid catalyst, reagent ratio, and acetylating agent on the conversion, selectivities, and byproducts formed. The variations are discussed and explained in terms of reactivity, thermodynamics, and reaction mechanisms. An alternative and efficient approach to the formation of 100% triacetin involves the ring-opening, acid-catalyzed acetylation from solketal or glycerol formal with excesses of acetic anhydride. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    NARCIS (Netherlands)

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

    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

  3. Improved glycerol production from cane molasses by the sulfite process with vacuum or continuous carbon dioxide sparging during fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Kalle, G.P.; Naik, S.C.; Lashkari, B.Z.

    1985-01-01

    The conventional sulfite process for glycerol production from molasses using Saccharomyces cerevisiae var. Hansen was modified to obtain product concentrations of up to 230 g/l and productivity of 15 g/l x d by fermenting under vacuum (80 mm) or with continuous sparging of CO/sub 2/ (0.4 vvm). Under these conditions the requirement of sulfite for optimum production of glycerol was reduced by two thirds (20 g/l), the ethanol concentration in the medium was kept below 30 g/l and the competence of yeast cells to ferment was conserved throughout the fermentation period for up to 20 days. In addition to the above, the rate of incorporation of sulfite had a significant effect on glucose fermentation and glycerol yields. There was an optimal relationship between glycerol yields and the molar ratio of sulfite to glucose consumed, which for cane molasses was 0.67. This ratio was characteristic of the medium composition. 10 references, 4 figures, 3 tables.

  4. Glycerol supplementation of the growth medium enhances in situ detoxification of furfural by Clostridium beijerinckii during butanol fermentation.

    Science.gov (United States)

    Ujor, Victor; Agu, Chidozie Victor; Gopalan, Venkat; Ezeji, Thaddeus Chukwuemeka

    2014-01-01

    Lignocellulose-derived microbial inhibitors such as furfural and 5-hydroxymethyl furfural adversely affect fermentation of lignocellulosic biomass hydrolysates to fuels and chemicals due to their toxicity on fermenting microbes. To harness the potential of lignocellulose as a cheap source of fermentable sugars, in situ detoxification of furfural and other lignocellulose-derived microbial inhibitors is essential. To enhance in situ detoxification and tolerance of furfural by Clostridium beijerinckii NCIMB 8052 during acetone-butanol-ethanol (ABE) fermentation, the effect of glycerol on NADH/NADPH generation and ABE production by furfural (4, 5, and 6 g/L)-challenged cultures was investigated in this study. In all instances, beneficial outcomes were observed. For example, the fermentation medium supplemented with glycerol and subjected to 5 g/L furfural elicited up to 1.8- and 3-fold increases, respectively, in NADH and NADPH levels in C. beijerinckii 8052 relative to the control culture. These critical changes are the likely underpinnings for the glycerol-mediated 2.3-fold increase in the rate of detoxification of 5 g/L furfural, substrate consumption, and ABE production compared to the unsupplemented medium. Collectively, these results demonstrate that increased intracellular NADH/NADPH in C. beijerinckii 8052 due to glycerol utilization engenders favorable effects on many aspects of cellular metabolism, including enhanced furfural reduction and increased ABE production.

  5. Prebiotic Peptide (Amide) Bond Synthesis Accelerated by Glycerol and Bicarbonate Under Neutral to Alkaline Dry-Down Conditions

    Science.gov (United States)

    Forsythe, J. G.; Weber, A. L.

    2017-07-01

    We report a new process for robust peptide bond synthesis in the pH 6–10 range that involves dry-down heating of amino acids in the presence of glycerol and bicarbonate (substrates: L-alanine, L-2-aminobutyric acid, β-alanine, isoserine).

  6. Enhanced performance of a novel anodic PdAu/VGCNF catalyst for electro-oxidation in a glycerol fuel cell.

    Science.gov (United States)

    Yahya, N; Kamarudin, S K; Karim, N A; Masdar, M S; Loh, K S

    2017-11-25

    This study presents a novel anodic PdAu/VGCNF catalyst for electro-oxidation in a glycerol fuel cell. The reaction conditions are critical issues affecting the glycerol electro-oxidation performance. This study presents the effects of catalyst loading, temperature, and electrolyte concentration. The glycerol oxidation performance of the PdAu/VGCNF catalyst on the anode side is tested via cyclic voltammetry with a 3 mm 2 active area. The morphology and physical properties of the catalyst are examined using X-ray diffraction (XRD), field emission scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. Then, optimization is carried out using the response surface method with central composite experimental design. The current density is experimentally obtained as a response variable from a set of experimental laboratory tests. The catalyst loading, temperature, and NaOH concentration are taken as independent parameters, which were evaluated previously in the screening experiments. The highest current density of 158.34 mAcm -2 is obtained under the optimal conditions of 3.0 M NaOH concentration, 60 °C temperature and 12 wt.% catalyst loading. These results prove that PdAu-VGCNF is a potential anodic catalyst for glycerol fuel cells.

  7. How Glycerol and Water Contents Affect the Structural and Functional Properties of Starch-Based Edible Films

    Directory of Open Access Journals (Sweden)

    Ewelina Basiak

    2018-04-01

    Full Text Available As starch is an inexpensive, filmogenic, easily processable and a widely available material, it is a material that can be utilized in the creation of biodegradable films and containers, presenting as a viable alternative to polymers derived from petrol. Moreover, starch could also be used to create edible coatings for fresh foods in order to extend shelf life. As such, wheat starch films with two glycerol contents were formulated to mimic the effects of compounds currently used to coat fruit. Their structural and functional properties were characterized. This study found that the transfer properties of starch films containing 33% of plasticizer was less effective than film comprised of 50% glycerol. Water diffusivity, oxygen permeability, and water vapor permeability at two different humidity gradients, surface tension, works of surface adhesion and cohesion, and moisture sorption were tested. Glycerol content does not play a significant role on the color or mechanical properties. This work shows that glycerol can strongly affect the functional properties of starch-based coatings and films.

  8. Simultaneous stable carbon isotopic analysis of wine glycerol and ethanol by liquid chromatography coupled to isotope ratio mass spectrometry.

    Science.gov (United States)

    Cabañero, Ana I; Recio, Jose L; Rupérez, Mercedes

    2010-01-27

    A novel procedure was established for the simultaneous characterization of wine glycerol and ethanol (13)C/(12)C isotope ratio, using liquid chromatography/isotope ratio mass spectrometry (LC-IRMS). Several parameters influencing separation of glycerol and ethanol from wine matrix were optimized. Results obtained for 35 Spanish samples exposed no significant differences and very strong correlations (r = 0.99) between the glycerol (13)C/(12)C ratios obtained by an alternative method (gas chromatography/isotope ratio mass spectrometry) and the proposed new methodology, and between the ethanol (13)C/(12)C ratios obtained by the official method (elemental analyzer/isotope ratio mass spectrometry) and the proposed new methodology. The accuracy of the proposed method varied from 0.01 to 0.19 per thousand, and the analytical precision was better than 0.25 per thousand. The new developed LC-IRMS method it is the first isotopic method that allows (13)C/(12)C determination of both analytes in the same run directly from a liquid sample with no previous glycerol or ethanol isolation, overcoming technical difficulties associated with complex sample treatment and improving in terms of simplicity and speed.

  9. 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

  10. Highly selective bimetallic Pt-Cu/Mg(Al)O catalysts for the aqueous-phase reforming of glycerol

    NARCIS (Netherlands)

    Boga, D.A.; Oord, R.; Beale, A.M.; Chung, Y.M.; Bruijnincx, P.C.A.; Weckhuysen, B.M.

    2013-01-01

    Monometallic Pt and bimetallic Pt-Cu catalysts supported on Mg(Al)O mixed oxides, obtained by calcination of the corresponding layered double hydroxides (LDHs), were prepared and tested in the aqueous-phase reforming (APR) of glycerol. The effect of the Mg/Al ratio and calcination temperature of the

  11. Synthesis of non-natural carbohydrates from glycerol and aldehydes in a one-pot four-enzyme cascade reaction

    NARCIS (Netherlands)

    Babich, L.; Hartog, L.; Falcicchio, P.; Oost, van der J.

    2011-01-01

    A simple procedure has been developed for the synthesis of enantio- and diastereomerically pure carbohydrate analogues from glycerol and a variety of aldehydes in one pot using a four-enzyme cascade reaction. As a proof of concept of the usefulness of this enzymatic catalytic cascade the naturally

  12. Exploring the potential of the glycerol-3-phosphate dehydrogenase 2 (GPD2) promoter for recombinant gene expression in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Knudsen, Jan Dines; Johanson, Ted; Eliasson Lantz, Anna

    2015-01-01

    A control point for keeping redox homeostasis in Saccharomyces cerevisiae during fermentative growth is the dynamic regulation of transcription for the glycerol-3-phosphate dehydrogenase 2 (GPD2) gene. In this study, the possibility to steer the activity of the GPD2 promoter was investigated by p...

  13. 1,3-Propanediol production by Klebsiella oxytoca NRRL-B199 from glycerol. Medium composition and operational conditions

    Directory of Open Access Journals (Sweden)

    Mateusz Wojtusik

    2015-06-01

    Under the best operating conditions, i.e., a programmed variable stirring rate ranging from 50 to 100 rpm and a temperature of 37 °C, a final concentration of 13.5 g/L of 1,3-propanediol with a selectivity of 86% with respect to the glycerol consumed was obtained.

  14. Supplementation of glycerol or fructose via drinking water to grazing lambs on tissue glycogen level and lipogenesis.

    Science.gov (United States)

    Volpi-Lagreca, G; Duckett, S K

    2017-06-01

    Lambs ( = 18; 40.1 ± 7.4 kg BW) were used to assess supplementation of glycerol or fructose via drinking water on growth, tissue glycogen levels, postmortem glycolysis, and lipogenesis. Lambs were blocked by BW and allocated to alfalfa paddocks (2 lambs/paddock and 3 paddocks/treatment). Each paddock within a block was assigned randomly to drinking water treatments for 30 d: 1) control (CON), 2) 120 g fructose/L of drinking water (FRU), or 3) 120 g glycerol/L of drinking water (GLY). Lambs grazed alfalfa with free access to water treatments for 28 d and then were fasted in indoor pens for a final 2 d with access to only water treatments. Data were analyzed using the MIXED procedure of SAS with water treatment and time (when appropriate) in the model. During the 28-d grazing period, ADG was greater ( glycogen content × postmortem time was significant ( = 0.003) in LM and semitendinosus (ST) muscles. Glycogen content in the LM was greater ( Glycogen content in ST did not differ between treatments ( > 0.05). Liver glycogen content was over 14-fold greater ( glycogen branching enzyme in the liver. Overall, glycerol supplementation improved growth, reduced BW shrink during fasting, increased glycogen content in muscle and the liver, and stimulated de novo lipogenesis.

  15. Production of Fungal Biomass for Feed, Fatty Acids, and Glycerol by Aspergillus oryzae from Fat-Rich Dairy Substrates

    Directory of Open Access Journals (Sweden)

    Amir Mahboubi

    2017-09-01

    Full Text Available Dairy waste is a complex mixture of nutrients requiring an integrated strategy for valorization into various products. The present work adds insights into the conversion of fat-rich dairy products into biomass, glycerol, and fatty acids via submerged cultivation with edible filamentous fungi. The pH influenced fat degradation, where Aspergillus oryzae lipase was more active at neutral than acidic pH (17 g/L vs. 0.5 g/L of released glycerol; the same trend was found during cultivation in crème fraiche (12 g/L vs. 1.7 g/L of released glycerol. In addition to glycerol, as a result of fat degradation, up to 3.6 and 4.5 g/L of myristic and palmitic acid, respectively, were released during A. oryzae growth in cream. The fungus was also able to grow in media containing 16 g/L of lactic acid, a common contaminant of dairy waste, being beneficial to naturally increase the initial acidic pH and trigger fat degradation. Considering that lactose consumption is suppressed in fat-rich media, a two-stage cultivation for conversion of dairy waste is also proposed in this work. Such an approach would provide biomass for possibly feed or human consumption, fatty acids, and an effluent of low organic matter tackling environmental and social problems associated with the dairy sector.

  16. Egg yolk and glycerol requirements for freezing boar spermatozoa treated with methyl β-cyclodextrin or cholesterol-loaded cyclodextrin.

    Science.gov (United States)

    Blanch, Eva; Tomás, Cristina; Hernández, Marta; Roca, Jordi; Martínez, Emilio A; Vázquez, Juan M; Mocé, Eva

    2014-04-24

    Egg yolk (EY) and glycerol are common constituents of extenders used for sperm cryopreservation. It has been demonstrated that using cholesterol-loaded cyclodextrins (CLC) improves sperm cryosurvival in several species. However, standard freezing extenders might not be the most appropriate for CLC-treated sperm. This study evaluated the EY and glycerol requirements for freezing CLC-treated boar spermatozoa. Semen samples from 34 ejaculates coming from 4 boars were used. Each ejaculate was split into three aliquots: one was used untreated (control), and the other two were treated with 1 mg of CLC or methyl-β-cyclodextrin/120 × 10(6) sperm for 15 min at 22 C prior to cryopreservation. Our results indicated that reducing the concentration of EY was detrimental for sperm viability after thawing (31.57 ± 2 vs. 19.89% ± 2 for 20 and 10% EY, respectively; P semen treated with CLC. On the other hand, it was observed that the traditional concentration of glycerol (3%) was not the appropriate for freezing CLC-treated sperm (61.10 ± 3 vs. 47.87% ± 3 viable sperm for control and CLC-treated sperm, respectively; P extenders for CLC-treated sperm. Nevertheless, additional studies will be needed to evaluate alternative cryoprotectants and to determine the effect of high glycerol concentrations on sperm functionality.

  17. Economic Risk Assessment of Early Stage Designs for Glycerol2Valorization in Biorefinery Concepts

    DEFF Research Database (Denmark)

    Loureiro da Costa Lira Gargalo, Carina; Cheali, Peam; Posada, John A.

    2016-01-01

    , and discount rate, among others, have high impact on the project’s profitability analysis. Therefore, the profitability was tested under uncertainties by using NPV and MSP as economic metrics. The robust ranking of solutions is presented with respect to minimum economic risk of the project being nonprofitable...... (failure to achieve a positive NPV times the consequential profit loss). It was found that the best potential options for glycerol valorization is through the production of either (i) lactic acid (9 MM$ with 63% probability of failure to achieve a positive NPV); (ii) succinic acid (14 MM$ with 76......%); or finally, (iii) 1,2-propanediol (16 MM$ with 68%). As a risk reduction strategy, a multiproduct biorefinery is suggested which is capable of switching between the production of lactic acid and succinic acid. This solution comes with increased capital investment; however, it leads to more robust NPV...

  18. Application of forward osmosis technology in crude glycerol fermentation biorefinery-potential and challenges

    DEFF Research Database (Denmark)

    Kalafatakis, S.; Braekevelt, S.; Lymperatou, A.

    2018-01-01

    feedstock, without the need for an energy-intensive regeneration step (e.g. RO), has been investigated. Butanol production during crude glycerol fermentation by Clostridium pasteurianum, has been selected as a model process and the effect of cross-flow velocity and the dilution of draw solution on the water...... flux during short-term experiments (200 min), were investigated. Statistical analysis revealed that the dilution of the draw solution is the most influential factor for the water flux. Subsequent modelling of an integrated FO-fermentation process, showed that water recoveries could lead to substantial...... extensively studied; however, regeneration of the draw solution (thereby generating clean water) requires application of an energy-intensive process step like reverse osmosis (RO). In this study, the potential of applying FO for direct water recirculation from diluted fermentation effluent to concentrated...

  19. Simultaneous enzymatic synthesis of FAME and triacetyl glycerol from triglycerides and methyl acetate.

    Science.gov (United States)

    Usai, E M; Gualdi, E; Solinas, V; Battistel, E

    2010-10-01

    In the presence of methyl acetate triglycerides such as vegetable oils are transformed simultaneously into the corresponding fatty acid methyl esters and triacetyl glycerol (triacetin). The reaction, catalyzed by lipases, was studied as a function of some critical parameters, such as type of catalyst, enzyme hydration and immobilization support. The aim of the work was to achieve a conversion of the triglyceride as high as possible and to maximize the yield of the triacetin, the reaction end point. It was found that by using the immobilized lipase from Candida antarctica yields as high as 80% of both fatty acid esters and triacetin could be achieved. These results were obtained by carefully controlling the amount of water present in the reaction medium and the hydration level of the enzyme macromolecule. Copyright © 2010 Elsevier Ltd. All rights reserved.

  20. Bi-functional biobased packing of the cassava starch, glycerol, licuri nanocellulose and red propolis.

    Directory of Open Access Journals (Sweden)

    Samantha Serra Costa

    Full Text Available The aim of this study was to characterize and determine the bi-functional efficacy of active packaging films produced with starch (4% and glycerol (1.0%, reinforced with cellulose nanocrystals (0-1% and activated with alcoholic extracts of red propolis (0.4 to 1.0%. The cellulose nanocrystals used in this study were extracted from licuri leaves. The films were characterized using moisture, water-activity analyses and water vapor-permeability tests and were tested regarding their total phenolic compounds and mechanical properties. The antimicrobial and antioxidant efficacy of the films were evaluated by monitoring the use of the active films for packaging cheese curds and butter, respectively. The cellulose nanocrystals increased the mechanical strength of the films and reduced the water permeability and water activity. The active film had an antimicrobial effect on coagulase-positive staphylococci in cheese curds and reduced the oxidation of butter during storage.

  1. Thermo-acoustical molecular interaction study in binary mixtures of glycerol and ethylene glycol

    Science.gov (United States)

    Kaur, Kirandeep; Juglan, K. C.; Kumar, Harsh

    2017-07-01

    Ultrasonic velocity, density and viscosity are measured over the entire composition range for binary liquid mixtures of glycerol (CH2OH-CHOH-CH2OH) and ethylene glycol (HOCH2CH2OH) at different temperatures and constant frequency of 2MHz using ultrasonic interferometer, specific gravity bottle and viscometer respectively. Measured experimental values are used to obtained various acoustical parameters such as adiabatic compressibility, acoustic impedance, intermolecular free length, relaxation time, ultrasonic attenuation, effective molar weight, free volume, available volume, molar volume, Wada's constant, Rao's constant, Vander Waal's constant, internal pressure, Gibb's free energy and enthalpy. The variation in acoustical parameters are interpreted in terms of molecular interactions between the components of molecules of binary liquid mixtures.

  2. Optimal design and planning of glycerol-based biorefinery supply chains under uncertainty

    DEFF Research Database (Denmark)

    Loureiro da Costa Lira Gargalo, Carina; Carvalho, Ana; Gernaey, Krist V.

    2017-01-01

    -echelon mixed integer linear programming problem is proposed based upon a previous model, GlyThink. In the new formulation, market uncertainties are taken into account at the strategic planning level. The robustness of the supply chain structures is analyzed based on statistical data provided...... by the implementation of the Monte Carlo method, where a deterministic optimization problem is solved for each scenario. Furthermore, the solution of the stochastic multi-objective optimization model, points to the Pareto set of trade-off solutions obtained when maximizing the NPV and minimizing environmental......The optimal design and planning of glycerol-based biorefinery supply chains is critical for the development and implementation of this concept in a sustainable manner. To achieve this, a decision-making framework is proposed in this work, to holistically optimize the design and planning...

  3. Characterization of polyurethane based on polyol synthesized from glycerol and hexamethylene diisocyanate

    International Nuclear Information System (INIS)

    Carvalho, Sabrina M.; Weber, Vanessa; Silva, Tailu N.; Barreto, Pedro L.M.

    2009-01-01

    A new polyol based on glycerol was synthesized and used in the production of polyurethane by reaction with hexamethylene diisocyanate. The polyol was characterized by nuclear magnetic resonance spectroscopy (NMR) and Fourier transform-infrared spectroscopy (FTIR). The polyurethane produced was characterized by FTIR, thermogravimetry (TG), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The polyol was shown to be reactive with hexamethylene diisocyanate, as the FTIR spectrum showed no free isocyanate groups and identified the presence of group -C=O of urethane groups. Analysis by DSC showed that the sample of polyurethane has a glass transition temperature around -8.53 deg C and SEM micrographs showed fracture and surface continuous and not broken. The thermogravimetric analysis showed that the polyurethane produced has a high thermal stability with a temperature of maximum degradation around 430 deg C. (author)

  4. Polymeric blends from post-consumer PET and polyester becoming of glycerol and phthalic acid

    International Nuclear Information System (INIS)

    Miranda, C.S.; Brioude, M.; Fiuza, R.P.; Luporini, S.; Carvalho, R.F.; Jose, N.M.

    2010-01-01

    Preparation of physical mixture or polymer blends is a very important method to obtain a final product with excellent balance of properties, where one component can compensate for the poor property of another, and is often a modified low cost compared to development and synthesis of a new polymer. PET has become a major waste of post-consumer plastics and aiming to remedy this problem, this work aims to obtain blends from recycled PET and polyesters derived from glycerol and phthalic acid. The material with higher proportion of PET showed better thermal properties, observed by TGA and DSC, with a similar profile of pure PET. In XRD analysis showed a semicrystalline, while the SEM is a smooth surface on all materials, characteristic of pure polyester. The ratio of 50% its surface showed a probable immiscibility of polymers. (author)

  5. Glycerol restores the p53 function in human lingual cancer cells bearing mutant p53

    International Nuclear Information System (INIS)

    Ota, Ichiro; Yane, Katsunari; Yuki, Kazue; Kanata, Hirokazu; Hosoi, Hiroshi; Miyahara, Hiroshi

    2001-01-01

    Mutations in p53, tumor suppressor gene, have recently been shown to have an impact on the clinical course of several human tumors, including head and neck cancers. The genetic status of the p53 gene has been focused on as the most important candidate among various cancer-related genes for prognosis-predictive assays of cancer therapy. We examined the restoration of radiation- or cisplatin (CDDP)-induced p53-dependent apoptosis in human lingual cancer cells. The results suggest that glycerol is effective in inducing a conformational change of p53 and restoring normal function of mutant p53, leading to enhanced radiosensitivity or chemosensitivity through the induction of apoptosis. We have also represented the same results in vivo as in vitro. Thus, this novel tool for enhancement of radiosensitivity or chemosensitivity in cancer cells bearing m p53 may be applicable for p53-targeted cancer therapy. (author)

  6. Thermodynamic analysis of cavity creating mutations in an engineered leucine zipper and energetics of glycerol-induced coiled coil stabilization.

    Science.gov (United States)

    Dürr, E; Jelesarov, I

    2000-04-18

    Protein stability in vitro can be influenced either by introduction of mutations or by changes in the chemical composition of the solvent. Recently, we have characterized the thermodynamic stability and the rate of folding of the engineered dimeric leucine zipper A(2), which has a strengthened hydrophobic core [Dürr, E., Jelesarov, I., and Bosshard, H. R. (1999) Biochemistry 38, 870-880]. Here we report on the energetic consequences of a cavity introduced by Leu/Ala substitution at the tightly packed dimeric interface and how addition of 30% glycerol affects the folding thermodynamics of A(2) and the cavity mutants. Folding could be described by a two-state transition from two unfolded monomers to a coiled coil dimer. Removal of six methylene groups by Leu/Ala substitutions destabilized the dimeric coiled coil by 25 kJ mol(-1) at pH 3.5 and 25 degrees C in aqueous buffer. Destabilization was purely entropic at around room temperature and became increasingly enthalpic at elevated temperatures. Mutations were accompanied by a decrease of the unfolding heat capacity by 0.5 kJ K(-1) mol(-1). Addition of 30% glycerol increased the free energy of folding of A(2) and the cavity mutants by 5-10 kJ mol(-1) and lowered the unfolding heat capacity by 25% for A(2) and by 50% for the Leu/Ala mutants. The origin of the stabilizing effect of glycerol varied with temperature. Stabilization of the parent leucine zipper A(2) was enthalpic with an unfavorable entropic component between 0 and 100 degrees C. In the case of cavity mutants, glycerol induced enthalpic stabilization below 50 degrees C and entropic stabilization above 50 degrees C. The effect of glycerol could not be accounted for solely by the enthalpy and entropy of transfer or protein surface from water to glycerol/water mixture. We propose that in the presence of glycerol the folded coiled coil dimer is better packed and displays less intramolecular fluctuations, leading to enhanced enthalpic interactions and to an

  7. Surfactant-promoted reactions of Cl2 and Br2 with Br- in glycerol.

    Science.gov (United States)

    Faust, Jennifer A; Dempsey, Logan P; Nathanson, Gilbert M

    2013-10-17

    Gas-liquid scattering experiments are used to explore reactions of gaseous Cl2 and Br2 with a 0.03 M solution of the surfactant tetrahexylammonium bromide (THABr) dissolved in glycerol. At thermal collision energies, 79 ± 2% of incident Cl2 molecules react with Br(-) to form Cl2Br(-) in the interfacial region. This reaction probability is three times greater than the reactivity of Cl2 with 3 M NaBr-glycerol, even though the interfacial Br(-) concentrations are similar in each solution. We attribute the high 79% uptake to the presence of surface THA(+) ions that stabilize the Cl2Br(-) intermediate as it is formed in the charged, hydrophobic pocket created by the hexyl chains. Cl2Br(-) generates the single exchange product BrCl in a 1% yield close to the surface, while the remaining 99% desorbs as the double exchange product Br2 over >0.1 s after diffusing deeply into the bulk. When NaCl is added to the surfactant solution in a 20:1 Cl(-)/Br(-) ratio, the Cl2 reaction probability drops from 79% to 46 ± 1%, indicating that Cl(-) in the interfacial region only partially blocks reaction with Br(-). In parallel, we observe that gaseous Br2 molecules dissolve in 0.03 M THABr for 10(4) times longer than in 3 M NaBr. We attribute this change to formation of stabilizing interfacial and bulk-phase THA(+)Br3(-) ion pairs, in analogy with the capture of Cl2 and formation of THA(+)Cl2Br(-) pairs. The THA(+) ion appears to be a powerful interfacial catalyst for promoting reaction of Cl2 and Br2 with Br(-) and for ferrying the resultant ions into solution.

  8. Glycerol gelatin for 3D-printing of implants using a paste extrusion technique

    Directory of Open Access Journals (Sweden)

    Kempin Wiebke

    2017-09-01

    Full Text Available Fused deposition modeling as an additive manufacturing technique has gained great popularity for the fabrication of medical devices as well as pharmaceutical dosage forms over the last years. Particularly the variety of geometries that can be printed determines the attractiveness of this technique enabling a shape adaption of e.g. implants. In the presented work the soft hydrogel material glycerol gelatin was investigated towards its applicability in 3D-printing as an alternative to the commonly applied and mostly rigid polyesters. Model implants loaded with the model drug quinine and with the shape of a hollow cylinder were printed via an extrusion based technique utilizing the piston feed in a hydrogel filled heatable syringe. Glycerol gelatin hydrogels need to be crosslinked to avoid gel-sol-transition at body temperature. For this purpose three different crosslinking methods (insertion, dipping, spraying with 1-ethyl-3-(3-dimethylaminopropyl carbodiimide (EDC and N-hydroxysuccinimide (NHS were evaluated regarding their crosslinking efficiency and drug losses during the crosslinking process. Dipping of the implant into an aqueous solution with at least 50 mM EDC and 10 mM NHS was found to be the most efficient crosslinking technique in conjunction with a smaller drug loss during processing compared to inserting. However, the use of hydrogels also causes problems as an intense and highly variable swelling of the printed structures during crosslinking (120.7 % ± 11.9 % for 10 times dipping in 50mM EDC/10 mM NHS and a great dependency of the volume on storage conditions complicate the preparation of tailor-made implants. The release of the model drug quinine from printed and crosslinked implants was fast and nearly completed within 6 hours.

  9. Lymphatic absorption of hypolipidemic compound, 1-O-[p-(myristyloxy)-alpha-methylcinnamoyl] glycerol (LK-903).

    Science.gov (United States)

    Sugihara, J; Furuuchi, S

    1988-02-01

    The intestinal absorption process of 1-O-[p-(myristyloxy)-alpha-methylcinnamoyl] glycerol (LK-903), a new hypolipidemic compound, was studied in rats. When 3H-LK-903 or 3H-LKA [3H-p- (myristyloxy)-alpha-methyl cinnamic acid], labeled at the cinnamic acid moiety, or 14C-LK-903, labeled at the glycerol moiety, were administered orally to thoracic duct-cannulated rats at a dose of 0.233 mmol/kg, 31.1, 6.7 and 18.1% of the dose, respectively, appeared in the lymph within 24 h. In this case, radioactive compounds in the lymph lipids consisted of LKA (radioactivity was not detected in the fraction of LKA with 14C-LK-903), LK-903, diglyceride analogues and triglyceride analogues. The percentages of the triglyceride analogues were the highest, followed by the diglyceride analogues. On the other hand, when doubly labeled LK-903 (3H/14C = 1, corrected ratio) was administered orally, the values of 3H/14C for the monoglyceride, diglyceride and triglyceride analogues in the lymph were 1.2-1.5, 1.7-1.9 and 1.9-2.7, respectively. The lymphatic absorption of LK-903 was stimulated by the presence of lecithin but inhibited by a high dose of triolein. The results indicated that (1) LK-903 formed micelles in the intestine, (2) a large part of LK-903 was absorbed as such, (3) a part of LK-903 was hydrolyzed in the intestinal mucosa, and (4) a part of LKA formed by hydrolysis was again utilized to synthesize the higher glycerides and absorbed via the lymphatic absorption route for lipids.

  10. 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.

  11. A Computational Tale of Two Enzymes: Glycerol Dehydration With or Without B12.

    Science.gov (United States)

    Kovačević, Borislav; Barić, Danijela; Babic, Darko; Bilić, Luka; Hanževački, Marko; Sandala, Gregory M; Radom, Leo; Smith, David M

    2018-06-12

    We present a series of QM/MM calculations aimed at understanding the mechanism of the biological dehydration of glycerol. Strikingly and unusually, this process is catalyzed by two different radical enzymes, one of which is a coenzyme-B 12 - dependent enzyme and the other which is a coenzyme-B 12 - independent enzyme. We show that glycerol dehydration in the presence of the coenzyme-B 12 -dependent enzyme proceeds via a 1,2-OH shift, which benefits from a significant catalytic reduction in the barrier. In contrast, the same reaction in the presence of the coenzyme-B 12 -independent enzyme is unlikely to involve the 1,2-OH shift; instead, a strong preference for direct loss of water from a radical intermediate is indicated. We show that this preference and, ultimately the evolution of such enzymes, is strongly linked with the reactivities of the species responsible for abstracting a hydrogen atom from the substrate. It appears that the hydrogen re-abstraction step involving the product-related radical is fundamental to the mechanistic preference. The unconventional 1,2-OH shift seems to be required to generate a product-related radical of sufficient reactivity to cleave the relatively inactive C-H bond arising from the B 12 cofactor. In the absence of B 12 , it is the relatively weak S-H bond of a cysteine residue that must be homolyzed. Such a transformation is much less demanding and its inclusion apparently enables a simpler overall dehydration mechanism.

  12. Electrospun Gelatin/poly(Glycerol Sebacate Membrane with Controlled Release of Antibiotics for Wound Dressing

    Directory of Open Access Journals (Sweden)

    Parisa Shirazaki

    2017-01-01

    Full Text Available Background: The most important risk that threatens the skin wounds is infections. Therefore, fabrication of a membrane as a wound dressing with the ability of antibiotic delivery in a proper delivery rate is especially important. Materials and Methods: Poly(glycerol sebacate (PGS was prepared from sebacic acid and glycerol with 1:1 ratio; then, it was added to gelatin in the 1:3 ratio and was dissolved in 80% (v/v acetic acid, and finally, ciprofloxacin was added in 10% (w/v of polymer solution. The gelatin/PGS membrane was fabricated using an electrospinning method. The membrane was cross-linked using ethyl-3-(3-dimethylaminopropyl carbodiimide ethyl-3-(3-dimethylaminopropylcarbodiim (EDC and N-hydroxysuccinimide (NHS in different time periods to achieve a proper drug release rate. Fourier-transform infrared (FTIR spectroscopy was being used to manifest the peaks of polymers and drug in the membrane. Scanning electron microscopy (SEM was used to evaluate the morphology, fibers diameter, pore size, and porosity before and after crosslinking process. Ultraviolet (UV-visible spectrophotometry was used to show the ciprofloxacin release from the cross-linked membrane. Results: FTIR analysis showed the characteristic peaks of gelatin, PGS, and ciprofloxacin without any added peaks after the crosslinking process. SEM images revealed that nanofibers' size increased during the crosslinking process and porosity was higher than 80% before and after crosslinking process. UV-visible spectrophotometry showed the proper rate of ciprofloxacin release occurred from cross-linked membrane that remaining in EDC/NHS ethanol solution for 120 min. Conclusion: The obtained results suggest that this recently developed gelatin/PGS membrane with controlled release of ciprofloxacin could be a promising biodegradable membrane for wound dressing.

  13. Membrane permeability of the human granulocyte to water, dimethyl sulfoxide, glycerol, propylene glycol and ethylene glycol.

    Science.gov (United States)

    Vian, Alex M; Higgins, Adam Z

    2014-02-01

    Granulocytes are currently transfused as soon as possible after collection because they rapidly deteriorate after being removed from the body. This short shelf life complicates the logistics of granulocyte collection, banking, and safety testing. Cryopreservation has the potential to significantly increase shelf life; however, cryopreservation of granulocytes has proven to be difficult. In this study, we investigate the membrane permeability properties of human granulocytes, with the ultimate goal of using membrane transport modeling to facilitate development of improved cryopreservation methods. We first measured the equilibrium volume of human granulocytes in a range of hypo- and hypertonic solutions and fit the resulting data using a Boyle-van't Hoff model. This yielded an isotonic cell volume of 378 μm(3) and an osmotically inactive volume of 165 μm(3). To determine the permeability of the granulocyte membrane to water and cryoprotectant (CPA), cells were injected into well-mixed CPA solution while collecting volume measurements using a Coulter Counter. These experiments were performed at temperatures ranging from 4 to 37°C for exposure to dimethyl sulfoxide, glycerol, ethylene glycol, and propylene glycol. The best-fit water permeability was similar in the presence of all of the CPAs, with an average value at 21°C of 0.18 μmatm(-1)min(-1). The activation energy for water transport ranged from 41 to 61 kJ/mol. The CPA permeability at 21°C was 6.4, 1.0, 8.4, and 4.0 μm/min for dimethyl sulfoxide, glycerol, ethylene glycol, and propylene glycol, respectively, and the activation energy for CPA transport ranged between 59 and 68 kJ/mol. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Active site of Zn2+-dependent sn-glycerol-1-phosphate dehydrogenase from Aeropyrum pernix K1

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    Jin-Suk Han

    2005-01-01

    Full Text Available The enzyme sn-glycerol-1-phosphate dehydrogenase (Gro1PDH, EC 1.1.1.261 is key to the formation of the enantiomeric configuration of the glycerophosphate backbone (sn-glycerol-1-phosphate of archaeal ether lipids. This enzyme catalyzes the reversible conversion between dihydroxyacetone phosphate and glycerol-1-phosphate. To date, no information about the active site and catalytic mechanism of this enzyme has been reported. Using the sequence and structural information for glycerol dehydrogenase, we constructed six mutants (D144N, D144A, D191N, H271A, H287A and D191N/H271A of Gro1PDH from Aeropyrum pernix K1 and examined their characteristics to clarify the active site of this enzyme. The enzyme was found to be a zinc-dependent metalloenzyme, containing one zinc ion for every monomer protein that was essential for activity. Site-directed mutagenesis of D144 increased the activity of the enzyme. Mutants D144N and D144A exhibited low affinity for the substrates and higher activity than the wild type, but their affinity for the zinc ion was the same as that of the wild type. Mutants D191N, H271A and H287A had a low affinity for the zinc ion and a low activity compared with the wild type. The double mutation, D191N/ H271A, had no enzyme activity and bound no zinc. From these results, it was clarified that residues D191, H271 and H287 participate in the catalytic activity of the enzyme by binding the zinc ion, and that D144 has an effect on substrate binding. The structure of the active site of Gro1PDH from A. pernix K1 seems to be similar to that of glycerol dehydrogenase, despite the differences in substrate specificity and biological role.

  15. Bi-layered constructs of poly(glycerol-sebacate)-β-tricalcium phosphate for bone-soft tissue interface applications

    Energy Technology Data Exchange (ETDEWEB)

    Tevlek, Atakan [Bioengineering Division, Institute of Science and Engineering, Hacettepe University, Ankara (Turkey); Hosseinian, Pezhman; Ogutcu, Cansel [Nanotechnology and Nanomedicine Division, Institute of Science and Engineering, Hacettepe University, Ankara (Turkey); Turk, Mustafa [Biology Department, Kirikkale University, Kirikkale (Turkey); Aydin, Halil Murat, E-mail: hmaydin@hacettepe.edu.tr [Environmental Engineering Department, Bioengineering Division, Centre for Bioengineering, Hacettepe University, Ankara (Turkey)

    2017-03-01

    This study aims to establish a facile protocol for the preparation of a bi-layered poly(glycerol-sebacate) (PGS)/β-tricalcium phosphate (β-TCP) construct and to investigate its potential for bone-soft tissue engineering applications. The layered structure was prepared by distributing the ceramic particles within a prepolymer synthesized in a microwave reactor followed by a cross-linking of the final construct in vacuum (< 10 mbar). The vacuum stage led to the separation of cross-linked elastomer (top) and ceramic (bottom) phases. Results showed that addition of β-TCP particles to the elastomer matrix after the polymerization led to an increase in compression strength (up to 14 ± 2.3 MPa). Tensile strength (σ), Young's modulus (E), and elongation at break (%) values were calculated as 0.29 ± 0.03 MPa and 0.21 ± 0.03; 0.38 ± 0.02 and 1.95 ± 0.4; and 240 ± 50% and 24 ± 2% for PGS and PGS/β-TCP bi-layered constructs, respectively. Morphology was characterized by using Scanning Electron Microscopy (SEM) and micro-computed tomography (μ-CT). Tomography data revealed an open porosity of 35% for the construct, mostly contributed from the ceramic phase since the elastomer side has no pore. Homogeneous β-TCP distribution within the elastomeric structure was observed. Cell culture studies confirmed biocompatibility with poor elastomer-side and good bone-side cell attachment. In a further study to investigate the osteogenic properties, the construct were loaded with BMP-2 and/or TGF-β1. The PGS/β-TCP bi-layered constructs with improved mechanical and biological properties have the potential to be used in bone-soft tissue interface applications where soft tissue penetration is a problem. - Highlights: • Biodegradable bi-layered constructs with elastomer and ceramic sides were prepared. • The constructs could be a promising material in guided bone regeneration. • Elastomer side of the construct acts as a barrier to prevent soft tissue ingrowth.

  16. 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.

  17. Isolation and partial characterization of a new strain of Klebsiella pneumoniae capable of high 1,3 propanediol production from glycerol

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    B. Sen

    2015-04-01

    Full Text Available Glycerol is a promising feedstock for microbial cultivation and production of 1,3 propanediol (1,3 PDO. Here we report a newly isolated bacterial strain BA11 from soil, capable of fermenting glycerol to 1,3 PDO, and has been identified to be a strain of Klebsiella pneumoniae. Strain BA11 was fast growing showing peak 1,3 PDO production in 6 h of cultivation with productivity of 1.2 g/L-h without the addition of Vitamin B12. Based on the optimum glycerol utilization (75% and 1,3 PDO production (8.3 g/L and yield (0.56 mol/mol glycerol utilized, the most appropriate glycerol concentration for cultivation was 20 g/L. The strain BA11 could tolerate the pH range of 6 to 8.5 as no inhibitory effects were seen on growth as well as 1,3 PDO production. Strain BA11 was most active and could produce high 1,3 PDO in the incubation temperature range of 25 to 40 oC. The production of 1,3 PDO was maximum (9.3 g/L under aerobic condition with 95.8% glycerol utilization. Addition of glucose to the glycerol fermentation led to increased cell mass but no improvement in the 1,3 PDO production.

  18. Overexpression of the genes PDC1 and ADH1 activates glycerol conversion to ethanol in the thermotolerant yeast Ogataea (Hansenula) polymorpha.

    Science.gov (United States)

    Kata, Iwona; Semkiv, Marta V; Ruchala, Justyna; Dmytruk, Kostyantyn V; Sibirny, Andriy A

    2016-08-01

    Conversion of byproduct from biodiesel production glycerol to high-value compounds is of great importance. Ethanol is considered a promising product of glycerol bioconversion. The methylotrophic thermotolerant yeast Ogataea (Hansenula) polymorpha is of great interest for this purpose as the glycerol byproduct contains methanol and heavy metals as contaminants, and this yeast utilizes methanol and is relatively resistant to heavy metals. Besides, O. polymorpha shows robust growth on glycerol and produces ethanol from various carbon sources. The thermotolerance of this yeast is an additional advantage, allowing increased fermentation temperature to 45-48 °C, leading to increased rate of the fermentation process and a fall in the cost of distillation. The wild-type strain of O. polymorpha produces insignificant amounts of ethanol from glycerol (0.8 g/l). Overexpression of PDC1 coding for pyruvate decarboxylase enhanced ethanol production up to 3.1 g/l, whereas simultaneous overexpression of PDC1 and ADH1 (coding for alcohol dehydrogenase) led to further increase in ethanol production from glycerol. Moreover, the increased temperature of fermentation up to 45 °C stimulated the production of ethanol from glycerol used as the only carbon source up to 5.0 g/l, which exceeds the data obtained by methylotrophic yeast strains reported so far. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Co-Production of Ethanol and 1,2-Propanediol via Glycerol Hydrogenolysis Using Ni/Ce–Mg Catalysts: Effects of Catalyst Preparation and Reaction Conditions

    Directory of Open Access Journals (Sweden)

    Russel N. Menchavez

    2017-09-01

    Full Text Available Crude glycerol from biodiesel production is a biobased material capable of co-producing biofuels and chemicals. This study aimed to develop a line of Ni catalysts supported on cerium–magnesium (Ce–Mg to improve the process efficiency of glycerol hydrogenolysis for ethanol and 1,2-propanediol (1,2-PDO. Results showed that catalytic activity was greatly improved by changing the preparation method from impregnation to deposition precipitation (DP, and by adjusting calcination temperatures. Prepared via DP, the catalysts of 25 wt % Ni supported on Ce–Mg (9:1 mol/mol greatly improved the effectiveness in glycerol conversion while maintaining the selectivities to ethanol and 1,2-PDO. Calcination at 350 °C provided the catalysts better selectivities of 15.61% to ethanol and 67.93% to 1,2-PDO. Increases in reaction temperature and time improved the conversion of glycerol and the selectivity to ethanol, but reduced the selectivity to 1,2-PDO. A lower initial water content led to a higher conversion of glycerol, but lower selectivities to ethanol and 1,2-PDO. Higher hydrogen application affected the glycerol conversion rate positively, but the selectivities to ethanol and 1,2-PDO negatively. A comparison to the commercial Raney® Ni catalyst showed that the Ni/Ce–Mg catalyst developed in this study showed a better potential for the selective co-production of ethanol and 1,2-PDO from glycerol hydrogenolysis.

  20. Screening of bacterial strains capable of converting biodiesel-derived raw glycerol into 1,3-propanediol, 2,3-butanediol and ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Metsoviti, Maria; Paramithiotis, Spiros; Drosinos, Eleftherios H.; Galiotou-Panayotou, Maria; Nychas, George-John E.; Papanikolaou, Seraphim [Department of Food Science and Technology, Agricultural University of Athens, Athens (Greece); Zeng, An-Ping [Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology (TUHH), Hamburg (Germany)

    2012-02-15

    The ability of bacterial strains to assimilate glycerol derived from biodiesel facilities to produce metabolic compounds of importance for the food, textile and chemical industry, such as 1,3-propanediol (PD), 2,3-butanediol (BD) and ethanol (EtOH), was assessed. The screening of 84 bacterial strains was performed using glycerol as carbon source. After initial trials, 12 strains were identified capable of consuming raw glycerol under anaerobic conditions, whereas 5 strains consumed glycerol under aerobiosis. A plethora of metabolic compounds was synthesized; in anaerobic batch-bioreactor cultures PD in quantities up to 11.3 g/L was produced by Clostridium butyricum NRRL B-23495, while the respective value was 10.1 g/L for a newly isolated Citrobacter freundii. Adaptation of Cl. butyricum at higher initial glycerol concentration resulted in a PD{sub max} concentration of {proportional_to}32 g/L. BD was produced by a new Enterobacter aerogenes isolate in shake-flask experiments, under fully aerobic conditions, with a maximum concentration of {proportional_to}22 g/L which was achieved at an initial glycerol quantity of 55 g/L. A new Klebsiella oxytoca isolate converted waste glycerol into mixtures of PD, BD and EtOH at various ratios. Finally, another new C. freundii isolate converted waste glycerol into EtOH in anaerobic batch-bioreactor cultures with constant pH, achieving a final EtOH concentration of 14.5 g/L, a conversion yield of 0.45 g/g and a volumetric productivity of {proportional_to}0.7 g/L/h. As a conclusion, the current study confirmed the utilization of biodiesel-derived raw glycerol as an appropriate substrate for the production of PD, BD and EtOH by several newly isolated bacterial strains under different experimental conditions. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)