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Sample records for butanediols

  1. Enhancement of 2,3-butanediol production by Klebsiella ...

    African Journals Online (AJOL)

    2,3-Butanediol production parameter optimization using Klebsiella pneumoniae PTCC 1290 was performed using the design of experiments available in the form of an orthogonal array and a software for automatic design and analysis of the experiments, both based on Taguchi protocol. Optimal levels of physical ...

  2. Epoxidation and oxidation reactions using 1, 4-butanediol ...

    Indian Academy of Sciences (India)

    1,4-Butanediol dimethacrylate (1,4-BDDMA) crosslinked polystyrene-supported -butyl hydroperoxide was employed in the epoxidation of olefins and oxidation of alcohols to carbonyl compounds. The reagent proved to be successful as a recyclable solid phase organic reagent with as much or more efficiency when ...

  3. Enhancement of 2,3-butanediol production by Klebsiella ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-11-16

    Nov 16, 2009 ... 2,3-Butanediol production parameter optimization using Klebsiella pneumoniae PTCC 1290 was performed using the design of experiments available in the form of an orthogonal array and a software for automatic design and analysis of the experiments, both based on Taguchi protocol. Optimal levels.

  4. Interaction between 1,4-butanediol and ethanol on operant responding and the cardiovascular system.

    Science.gov (United States)

    Gerak, Lisa R; Hicks, Alissa R; Winsauer, Peter J; Varner, Kurt J

    2004-12-03

    The current studies characterized the rate-decreasing and cardiovascular responses produced by 1,4-butanediol administered alone and in combination with ethanol to test the hypothesis that these effects resulted from the degradation of 1,4-butanediol to gamma-hydroxybutyrate. One group of rats responded under a fixed-ratio 20 schedule of food presentation; ethanol and 1,4-butanediol dose-dependently decreased response rates. Ethanol administered in combination with 1,4-butanediol attenuated the rate-decreasing effects of 1,4-butanediol without altering the potency of ethanol. In separate groups of conscious rats, radio telemetry was used to record mean arterial pressure and heart rate. In contrast to its depressant effects on schedule-controlled responding, 1,4-butanediol increased mean arterial pressure and heart rate; these increases were attenuated by ethanol. Thus, the behavioral and cardiovascular actions of 1,4-butanediol are similar to those elicited by gamma-hydroxybutyrate. The ability of ethanol to attenuate the behavioral and cardiovascular effects of 1,4-butanediol indicates that these effects require the conversion of 1,4-butanediol to gamma-hydroxybutyrate.

  5. Production of 2,3-butanediol in Saccharomyces cerevisiae by in silico aided metabolic engineering

    Directory of Open Access Journals (Sweden)

    Ng Chiam Yu

    2012-05-01

    Full Text Available Abstract Background 2,3-Butanediol is a chemical compound of increasing interest due to its wide applications. It can be synthesized via mixed acid fermentation of pathogenic bacteria such as Enterobacter aerogenes and Klebsiella oxytoca. The non-pathogenic Saccharomyces cerevisiae possesses three different 2,3-butanediol biosynthetic pathways, but produces minute amount of 2,3-butanediol. Hence, we attempted to engineer S. cerevisiae strain to enhance 2,3-butanediol production. Results We first identified gene deletion strategy by performing in silico genome-scale metabolic analysis. Based on the best in silico strategy, in which disruption of alcohol dehydrogenase (ADH pathway is required, we then constructed gene deletion mutant strains and performed batch cultivation of the strains. Deletion of three ADH genes, ADH1, ADH3 and ADH5, increased 2,3-butanediol production by 55-fold under microaerobic condition. However, overproduction of glycerol was observed in this triple deletion strain. Additional rational design to reduce glycerol production by GPD2 deletion altered the carbon fluxes back to ethanol and significantly reduced 2,3-butanediol production. Deletion of ALD6 reduced acetate production in strains lacking major ADH isozymes, but it did not favor 2,3-butanediol production. Finally, we introduced 2,3-butanediol biosynthetic pathway from Bacillus subtilis and E. aerogenes to the engineered strain and successfully increased titer and yield. Highest 2,3-butanediol titer (2.29 g·l-1 and yield (0.113 g·g-1 were achieved by Δadh1 Δadh3 Δadh5 strain under anaerobic condition. Conclusions With the aid of in silico metabolic engineering, we have successfully designed and constructed S. cerevisiae strains with improved 2,3-butanediol production.

  6. Engineered Serratia marcescens for efficient (3R)-acetoin and (2R,3R)-2,3-butanediol production.

    Science.gov (United States)

    Bai, Fangmin; Dai, Lu; Fan, Jiying; Truong, Ngoctu; Rao, Ben; Zhang, Liaoyuan; Shen, Yaling

    2015-05-01

    (3R)-Acetoin and (2R,3R)-2,3-butanediol are important pharmaceutical intermediates. However, until now, the quantity of natural microorganisms with the ability to produce single configuration of optically pure (3R)-acetoin and (2R,3R)-2,3-butanediol is rare. In this study, a meso-2,3-butanediol dehydrogenase encoded by the slaC gene from Serratia marcescens MG1 was identified for meso-2,3-butanediol and (2S,3S)-2,3-butanediol biosynthesis. Inactivation of the slaC gene could significantly decrease meso-2,3-butanediol and (2S,3S)-2,3-butanediol and result in a large quantity of (3R)-acetoin accumulation. Furthermore, a (2R,3R)-2,3-butanediol dehydrogenase encoded by the bdhA gene from Bacillus subtilis 168 was introduced into the slaC mutant strain of Serratia marcescens MG1. Excess (2R,3R)-2,3-butanediol dehydrogenase could accelerate the reaction from (3R)-acetoin to (2R,3R)-2,3-butanediol and lead to (2R,3R)-2,3-butanediol accumulation. In fed-batch fermentation, the excess (2R,3R)-2,3-butanediol dehydrogenase expression strain could produce 89.81 g/l (2R,3R)-2,3-butanediol with a productivity of 1.91 g/l/h at 48 h. These results provided potential applications for (3R)-acetoin and (2R,3R)-2,3-butanediol production.

  7. Effect of deletion of 2,3-butanediol dehydrogenase gene (bdhA) on acetoin production of Bacillus subtilis.

    Science.gov (United States)

    Zhang, Junjiao; Zhao, Xiangying; Zhang, Jiaxiang; Zhao, Chen; Liu, Jianjun; Tian, Yanjun; Yang, Liping

    2017-09-14

    The present work aims to block 2,3-butanediol synthesis in acetoin fermentation of Bacillus subtilis. First, we constructed a recombinant strain BS168D by deleting the 2,3-butanediol dehydrogenase gene bdhA of the B. subtilis168, and there was almost no 2,3-butanediol production in 20 g/L of glucose media. The acetoin yield of BS168D reached 6.61 g/L, which was about 1.5 times higher than that of the control B. subtilis168 (4.47 g/L). Then, when the glucose concentration was increased to 100 g/L, the acetoin yield reached 24.6 g/L, but 2.4 g/L of 2,3-butanediol was detected at the end of fermentation. The analysis of 2,3-butanediol chiral structure indicated that the main 2,3-butanediol production of BS168D was meso-2,3-butanediol, and the bdhA gene was only responsible for (2R,3R)-2,3-butanediol synthesis. Therefore, we speculated that there may exit another pathway relating to the meso-2,3-butanediol synthesis in the B. subtilis. In addition, the results of low oxygen condition fermentation showed that deletion of bdhA gene successfully blocked the reversible transformation between acetoin and 2,3-butanediol and eliminated the effect of dissolved oxygen on the transformation.

  8. Efficacy of 1,3-butanediol for enhancement of neonatal pig survival.

    Science.gov (United States)

    Stahly, Tim S; Raff, Donald K; Frey, Guido D; Zamzow, Jeremias B

    2014-08-01

    Pre-partum feeding of 1,3-butanediol to sows has been shown to improve the metabolic status and survival rate of neonatal pigs. To evaluate the efficacy of short-term, pre-partum feeding of 1,3-butanediol on pig and sow productivity on a large scale and low concentration was the focus of the research. The secondary objective was to determine if pre-partum feeding of 1,3-butanediol had any effect on survival rate and weight gain of lesser body weight pigs, sow body weight and subsequent sow reproductive performance. In a large commercial unit, 2537 sows were fed one of two pre-partum diets (0% or 4.55% 1,3-butanediol) on Day 108±3 of pregnancy. 1,3-butanediol provided 8% of the total metabolizable energy. Pigs born live in those litters were equalized by cross-fostering among sows receiving the same pre-partum diet. Pigs were weaned from the sows at 16±3 days post-partum and return of sows to estrus and conception rates were determined. Pre-partum feeding of 1,3-butanediol reduced (P=0.01) pre-weaning pig mortalities from 1.44 to 1.24 pigs per litter. The reduction in pig mortality was independent of length of 1,3-butanediol feeding (4 to 11 days). In a subset of 750 litters, four lesser birth-weight pigs from each litter were tagged and monitored to determine the effect of 1,3-butanediol on survival rates and pre-weaning weight gain of pigs with the greatest mortality risk. 1,3-butanediol reduced (P=0.01) pre-weaning mortality of these low birth weight pigs by 5.27%. Based on these data, short-term pre-partum feeding of 1,3-butanediol effectively improves pre-weaning pig productivity at a lower concentration than previously reported. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Characterization and regulation of the 2,3-butanediol pathway in Serratia marcescens.

    Science.gov (United States)

    Rao, Ben; Zhang, Liao Yuan; Sun, Jian'an; Su, Gang; Wei, Dongzhi; Chu, Ju; Zhu, Jiawen; Shen, Yaling

    2012-03-01

    Serratia marcescens has been proved to be a potential strain for industrial 2,3-butanediol production for its high yield, productivity, and other advantages. In this study, the genes slaA, slaB, slaC, and slaR were successfully cloned which were further confirmed to be encoding acetolactate decarboxylase, acetolactate synthase, 2,3-butanediol dehydrogenase, and a LysR-like regulator, respectively. Unlike in Klebsiella sp. or Klebsiella pneumonie and Vibrio sp. or Vibrio cholerae, the gene slaC is separated from other genes. Then it showed that two regulators, SwrR and SlaR, are in charge of this process by exerting effect on the transcription of genes slaA and slaB. By contrast, the expression of gene slaC is unaffected by the two regulators. It means that these two regulators affect the production of 2,3-butanediol by regulating the production of acetoin. Based on these findings, we successfully accelerated the 2,3-butanediol production by inactivation of gene swrR. The obtained results and further investigations should lead to a more suitable fermentation strategy and strain improvement which would be applicable to the industrial production of 2,3-butanediol.

  10. Enhancement of 2,3-Butanediol Production by Klebsiella oxytoca PTCC 1402

    Directory of Open Access Journals (Sweden)

    Maesomeh Anvari

    2011-01-01

    Full Text Available Optimal operating parameters of 2,3-Butanediol production using Klebsiella oxytoca under submerged culture conditions are determined by using Taguchi method. The effect of different factors including medium composition, pH, temperature, mixing intensity, and inoculum size on 2,3-butanediol production was analyzed using the Taguchi method in three levels. Based on these analyses the optimum concentrations of glucose, acetic acid, and succinic acid were found to be 6, 0.5, and 1.0 (% w/v, respectively. Furthermore, optimum values for temperature, inoculum size, pH, and the shaking speed were determined as 37°C, 8 (g/L, 6.1, and 150 rpm, respectively. The optimal combinations of factors obtained from the proposed DOE methodology was further validated by conducting fermentation experiments and the obtained results revealed an enhanced 2,3-Butanediol yield of 44%.

  11. Optimization of 2,3-butanediol production by Klebsiella oxytoca through oxygen transfer rate control

    Energy Technology Data Exchange (ETDEWEB)

    Beronio, P.B. Jr. (Amoco Oil Co., Naperville, IL (United States). Amoco Research Center); Tsao, G.T. (Purdue Univ., West Lafayette, IN (United States). Lab. of Renewable Resources Engineering)

    1993-12-01

    Production of 2,3-butanediol by Klebsiella oxytoca is influenced by the degree of oxygen limitation. During batch culture studies, two phases of growth are observed: energy-coupled growth, during which cell growth and oxygen supply are coupled; and, energy-uncoupled growth, which arises when the degree of oxygen limitation reaches a critical value. Optimal 2,3-butanediol productivity occurs during the energy-coupled growth phase. In this article, a control system which maintains the batch culture at a constant level of oxygen limitation in the energy-coupled growth regime has been designed. Control, which involves feedback control on the oxygen transfer coefficient, is achieved by continually increasing the partial pressure of oxygen in the feed gas, which in turn continually increases the oxygen transfer rate. Control has resulted in a balanced state of growth, a repression of ethanol formation, and an increase in 2,3-butanediol productivity of 18%.

  12. Gas-phase synthesis of 4-hydroxy-2-butanone by dehydrogenation of 1, 3-butanediol

    Energy Technology Data Exchange (ETDEWEB)

    Grishchenko, A.V.; Devekii, A.V.; Fedorov, V.S.; Grishchenko, N.F.

    1985-05-10

    The authors studied a new method for the production of 4-hydroxy2-butanone by catalytic dehydrogenation of 1,3-butanediol, in order to find the best synthesis conditions. They therefore studied a series of heterogeneous catalysts, among which copper-containing catalysts had the highest activity. The study shows that 4-hydroxy2-butanone containing about 1.5 mass % of ketones of various structures as by-products can be synthesized with up to 90% selectivity by dehydrogenation of 1,3-butanediol under atmospheric pressure at 120 and gaseous feed space velocity of 1.0 h .

  13. A case of withdrawal from the GHB precursors gamma-butyrolactone and 1,4-butanediol.

    Science.gov (United States)

    Schneir, A B; Ly, B T; Clark, R F

    2001-07-01

    We describe a case of withdrawal from the gamma hydroxybutyric acid (GHB) precursors gamma butyrolactone and 1,4-butanediol. Symptoms included visual hallucinations, tachycardia, tremor, nystagmus, and diaphoresis. Administration of benzodiazepines and phenobarbital successfully treated the withdrawal symptoms. As predicted from the metabolism of gamma butyrolactone and 1,4-butanediol to GHB, the symptoms were nearly identical to those reported from GHB withdrawal. Because GHB is now illegal in the United States, individuals have begun abusing the legal and easier to acquire GHB precursors. More frequent cases of both abuse and withdrawal from these GHB precursors can be expected.

  14. The kinetics of 1,4-butanediol diglycidyl ether crosslinking of dermal sheep collagen

    NARCIS (Netherlands)

    Zeeman, R.; Dijkstra, Pieter J.; van Wachem, Pauline B.; van Luyn, Marja J.A.; Hendriks, Marc; Cahalan, Patrick T.; Feijen, Jan

    2000-01-01

    Dermal sheep collagen was crosslinked with 1,4-butanediol diglycidyl ether (BDDGE) or modified with glycidyl isopropyl ether (PGE). The reduction in amine groups as a function of time was followed to study the overall reaction kinetics of collagen with either BDDGE or PGE. Linearization of the

  15. The kinetics of 1,4-butanediol diglycidyl ether crosslinking of dermal sheep collagen

    NARCIS (Netherlands)

    Zeeman, R; Dijkstra, PJ; van Wachem, PB; van Luyn, MJA; Hendriks, M; Cahalan, PT; Feijen, J

    2000-01-01

    Dermal sheep collagen was crosslinked with 1,4-butanediol diglycidyl ether (BDDGE) or modified with glycidyl isopropyl ether (PGE). The reduction in amine groups as a function of time was followed to study the overall reaction kinetics of collagen with either BDDGE or PGE;. Linearization of the

  16. Micro-organism for the production of stereo-specific s, s-2,3-butanediol

    DEFF Research Database (Denmark)

    2016-01-01

    lactic acid bacterium, under aerobic conditions in the presence of a source of iron-containing porphyrin or a source of metal ions (Fe3+/Fe2+). The lactic acid bacterium is genetically modified to express heterologous genes encoding enzymes catalysing the stereo-specific synthesis of (S,S)-2,3-butanediol...

  17. Assessing the stereoselectivity of Serratia marcescens CECT 977 2,3-butanediol dehydrogenase

    NARCIS (Netherlands)

    Medici, R.; Stammes, J.K.; Otten, L.G.; Hanefeld, U.; Kwakernaak, Stender

    2017-01-01

    α-Hydroxy ketones and vicinal diols constitute well-known building blocks in organic synthesis. Here we describe one enzyme that enables the enantioselective synthesis of both building blocks starting from diketones. The enzyme 2,3-butanediol dehydrogenase (BudC) from S. marcescens CECT 977 belongs

  18. Cloning, expression and characterization of glycerol dehydrogenase involved in 2,3-butanediol formation in Serratia marcescens H30.

    Science.gov (United States)

    Zhang, Liaoyuan; Xu, Quanming; Peng, Xiaoqian; Xu, Boheng; Wu, Yuehao; Yang, Yulong; Sun, Shujing; Hu, Kaihui; Shen, Yaling

    2014-09-01

    The meso-2,3-butanediol dehydrogenase (meso-BDH) from S. marcescens H30 is responsible for converting acetoin into 2,3-butanediol during sugar fermentation. Inactivation of the meso-BDH encoded by budC gene does not completely abolish 2,3-butanediol production, which suggests that another similar enzyme involved in 2,3-butanediol formation exists in S. marcescens H30. In the present study, a glycerol dehydrogenase (GDH) encoded by gldA gene from S. marcescens H30 was expressed in Escherichia coli BL21(DE3), purified and characterized for its properties. In vitro conversion indicated that the purified GDH could catalyze the interconversion of (3S)-acetoin/meso-2,3-butanediol and (3R)-acetoin/(2R,3R)-2,3-butanediol. (2S,3S)-2,3-Butanediol was not a substrate for the GDH at all. Kinetic parameters of the GDH enzyme showed lower K m value and higher catalytic efficiency for (3S/3R)-acetoin in comparison to those for (2R,3R)-2,3-butanediol and meso-2,3-butanediol, implying its physiological role in favor of 2,3-butanediol formation. Maximum activity for reduction of (3S/3R)-acetoin and oxidations of meso-2,3-butanediol and glycerol was observed at pH 8.0, while it was pH 7.0 for diacetyl reduction. The enzyme exhibited relative high thermotolerance with optimum temperature of 60 °C in the oxidation-reduction reactions. Over 60 % of maximum activity was retained at 70 °C. Additionally, the GDH activity was significantly enhanced for meso-2,3-BD oxidation in the presence of Fe(2+) and for (3S/3R)-acetoin reduction in the presence of Mn(2+), while several cations inhibited its activity, particularly Fe(2+) and Fe(3+) for (3S/3R)-acetoin reduction. The properties provided potential application for single configuration production of acetoin and 2,3-butanediol .

  19. Enantioselective Synthesis of Vicinal (R,R)-Diols by Saccharomyces cerevisiae Butanediol Dehydrogenase.

    Science.gov (United States)

    Calam, Eduard; González-Roca, Eva; Fernández, M Rosario; Dequin, Sylvie; Parés, Xavier; Virgili, Albert; Biosca, Josep A

    2016-01-04

    Butanediol dehydrogenase (Bdh1p) from Saccharomyces cerevisiae belongs to the superfamily of the medium-chain dehydrogenases and reductases and converts reversibly R-acetoin and S-acetoin to (2R,3R)-2,3-butanediol and meso-2,3-butanediol, respectively. It is specific for NAD(H) as a coenzyme, and it is the main enzyme involved in the last metabolic step leading to (2R,3R)-2,3-butanediol in yeast. In this study, we have used the activity of Bdh1p in different forms-purified enzyme, yeast extracts, permeabilized yeast cells, and as a fusion protein (with yeast formate dehydrogenase, Fdh1p)-to transform several vicinal diketones to the corresponding diols. We have also developed a new variant of the delitto perfetto methodology to place BDH1 under the control of the GAL1 promoter, resulting in a yeast strain that overexpresses butanediol dehydrogenase and formate dehydrogenase activities in the presence of galactose and regenerates NADH in the presence of formate. While the use of purified Bdh1p allows the synthesis of enantiopure (2R,3R)-2,3-butanediol, (2R,3R)-2,3-pentanediol, (2R,3R)-2,3-hexanediol, and (3R,4R)-3,4-hexanediol, the use of the engineered strain (as an extract or as permeabilized cells) yields mixtures of the diols. The production of pure diol stereoisomers has also been achieved by means of a chimeric fusion protein combining Fdh1p and Bdh1p. Finally, we have determined the selectivity of Bdh1p toward the oxidation/reduction of the hydroxyl/ketone groups from (2R,3R)-2,3-pentanediol/2,3-pentanedione and (2R,3R)-2,3-hexanediol/2,3-hexanedione. In conclusion, Bdh1p is an enzyme with biotechnological interest that can be used to synthesize chiral building blocks. A scheme of the favored pathway with the corresponding intermediates is proposed for the Bdh1p reaction. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  20. Improved Production of 2,3-Butanediol in Bacillus amyloliquefaciens by Over-Expression of Glyceraldehyde-3-Phosphate Dehydrogenase and 2,3-butanediol Dehydrogenase

    Science.gov (United States)

    Yang, Taowei; Rao, Zhiming; Zhang, Xian; Xu, Meijuan; Xu, Zhenghong; Yang, Shang-Tian

    2013-01-01

    Background Previously, a safe strain, Bacillus amyloliquefaciens B10-127 was identified as an excellent candidate for industrial-scale microbial fermentation of 2,3-butanediol (2,3-BD). However, B. amyloliquefaciens fermentation yields large quantities of acetoin, lactate and succinate as by-products, and the 2,3-BD yield remains prohibitively low for commercial production. Methodology/Principal Findings In the 2,3-butanediol metabolic pathway, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) catalyzes the conversion of 3-phosphate glyceraldehyde to 1,3-bisphosphoglycerate, with concomitant reduction of NAD+ to NADH. In the same pathway, 2,3-BD dehydrogenase (BDH) catalyzes the conversion of acetoin to 2,3-BD with concomitant oxidation of NADH to NAD+. In this study, to improve 2,3-BD production, we first over-produced NAD+-dependent GAPDH and NADH-dependent BDH in B. amyloliquefaciens. Excess GAPDH reduced the fermentation time, increased the 2,3-BD yield by 12.7%, and decreased the acetoin titer by 44.3%. However, the process also enhanced lactate and succinate production. Excess BDH increased the 2,3-BD yield by 16.6% while decreasing acetoin, lactate and succinate production, but prolonged the fermentation time. When BDH and GAPDH were co-overproduced in B. amyloliquefaciens, the fermentation time was reduced. Furthermore, in the NADH-dependent pathways, the molar yield of 2,3-BD was increased by 22.7%, while those of acetoin, lactate and succinate were reduced by 80.8%, 33.3% and 39.5%, relative to the parent strain. In fed-batch fermentations, the 2,3-BD concentration was maximized at 132.9 g/l after 45 h, with a productivity of 2.95 g/l·h. Conclusions/Significance Co-overexpression of bdh and gapA genes proved an effective method for enhancing 2,3-BD production and inhibiting the accumulation of unwanted by-products (acetoin, lactate and succinate). To our knowledge, we have attained the highest 2,3-BD fermentation yield thus far reported for safe

  1. Improved production of 2,3-butanediol in Bacillus amyloliquefaciens by over-expression of glyceraldehyde-3-phosphate dehydrogenase and 2,3-butanediol dehydrogenase.

    Directory of Open Access Journals (Sweden)

    Taowei Yang

    Full Text Available Previously, a safe strain, Bacillus amyloliquefaciens B10-127 was identified as an excellent candidate for industrial-scale microbial fermentation of 2,3-butanediol (2,3-BD. However, B. amyloliquefaciens fermentation yields large quantities of acetoin, lactate and succinate as by-products, and the 2,3-BD yield remains prohibitively low for commercial production.In the 2,3-butanediol metabolic pathway, glyceraldehyde-3-phosphate dehydrogenase (GAPDH catalyzes the conversion of 3-phosphate glyceraldehyde to 1,3-bisphosphoglycerate, with concomitant reduction of NAD(+ to NADH. In the same pathway, 2,3-BD dehydrogenase (BDH catalyzes the conversion of acetoin to 2,3-BD with concomitant oxidation of NADH to NAD(+. In this study, to improve 2,3-BD production, we first over-produced NAD(+-dependent GAPDH and NADH-dependent BDH in B. amyloliquefaciens. Excess GAPDH reduced the fermentation time, increased the 2,3-BD yield by 12.7%, and decreased the acetoin titer by 44.3%. However, the process also enhanced lactate and succinate production. Excess BDH increased the 2,3-BD yield by 16.6% while decreasing acetoin, lactate and succinate production, but prolonged the fermentation time. When BDH and GAPDH were co-overproduced in B. amyloliquefaciens, the fermentation time was reduced. Furthermore, in the NADH-dependent pathways, the molar yield of 2,3-BD was increased by 22.7%, while those of acetoin, lactate and succinate were reduced by 80.8%, 33.3% and 39.5%, relative to the parent strain. In fed-batch fermentations, the 2,3-BD concentration was maximized at 132.9 g/l after 45 h, with a productivity of 2.95 g/l·h.Co-overexpression of bdh and gapA genes proved an effective method for enhancing 2,3-BD production and inhibiting the accumulation of unwanted by-products (acetoin, lactate and succinate. To our knowledge, we have attained the highest 2,3-BD fermentation yield thus far reported for safe microorganisms.

  2. Production of 2,3-butanediol from pretreated corn cob by Klebsiella oxytoca in the presence of fungal cellulase

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Ningjun; Xia Youkun; Gong, Cheng, S.; Tsao, G.T. [Purdue Univ., West Lafayette, IN (United States)

    1997-12-31

    A simple and effective method of treatment of lignocellulosic material was used for the preparation of corn cob for the production of 2,3-butane-diol by Klebsiella oxytoca ATCC 8724 in a simultaneous saccharification and fermentation process. During the treatment, lignin, and alkaline extractives were solubilized and separated from cellulose and hemicellulose fractions by dilute ammonia (10%) steeping. Hemicellulose was then hydrolyzed by dilute hydrochloric acid (1%, w/v) hydrolysis at 100{degrees}C at atmospheric pressure and separated from cellulose fraction. The remaining solid, with 90% of cellulose, was then used as the substrate. A butane-diol concentration of 25 g/L and an ethanol concentration of 7 g/L were produced by K. oxytoca from 80 g/L of corn cob cellulose with a cellulose dosage of 8.5 IFPU/g corn cob cellulose after 72 h of SSF. With only dilute acid hydrolysis, a butanediol production rate of 0.21 g/L/h was obtained that is much lower than the case in which corn cob was treated with ammonia steeping prior to acid hydrolysis. The butanediol production rate for the latter was 0.36 g/L/h. 26 refs., 5 figs., 1 tab.

  3. Anionic Extraction for Efficient Recovery of Biobased 2,3-Butanediol-A Platform for Bulk and Fine Chemicals

    DEFF Research Database (Denmark)

    Drabo, Peter; Tiso, Till; Heyman, Benedikt

    2017-01-01

    2,3-Butanediol (BDO) presents a promising platform molecule for the synthesis of basic and fine chemicals. Biotechnological production of BDO from renewable resources with living microbes enables high concentrations in the fermentation broth. The recovery of high-boiling BDO from an aqueous ferme...

  4. Linear and cyclic ester Oligomers of succinic acid and 1,4-butanediol: Biocatalytic synthesis and characterization

    NARCIS (Netherlands)

    Habeych Narvaez, D.I.; Eggink, G.; Boeriu, C.G.

    2011-01-01

    The lipase-catalyzed synthesis of cyclic ester oligomers from non-activated succinic acid (A) and 1,4-butanediol (B) in the presence of immobilized Candida antarctica lipase B was investigated. Batch and pulse fed-batch systems were implemented to increase the formation of cyclic ester products. The

  5. Synthesis of (3R)-acetoin and 2,3-butanediol isomers by metabolically engineered Lactococcus lactis

    DEFF Research Database (Denmark)

    Kandasamy, Vijayalakshmi; Liu, Jianming; Dantoft, Shruti Harnal

    2016-01-01

    -BDO) and (2R,3R)-butanediol (R-BDO). Efficient production of (3R)-acetoin was accomplished using a strain where the competing lactate, acetate and ethanol forming pathways had been blocked. By introducing different alcohol dehydrogenases into this strain, either EcBDH from Enterobacter cloacae or SadB from...

  6. Effects of prepartum administration of 1,3-butanediol to sows on growth and survival of neonatal pigs.

    Science.gov (United States)

    Stahly, T S; Cromwell, G L; Monegue, H J

    1985-12-01

    In six trials, 158 late-term gravid sows were fed isocaloric amounts (8,500 kcal metabolizable energy/d) of a corn-soybean meal-based diet in which 20% of their daily metabolizable energy (ME) intake was supplied by either cornstarch or 1,3-butanediol (butanediol) from about d 105 of gestation to parturition. After parturition, all sows were allowed to consume a standard, corn-soybean meal-based lactation diet, ad libitum, during a 28-d lactation. Prepartum administration of butanediol, a stable, nonvolatile liquid that possesses anesthetic, antimicrobial and ketogenic properties, did not alter the voluntary feed intake or body weight changes of sows pre- or post-partum. Number of pigs born per litter, average pig birth weight and incidence of stillbirths were not influenced by the prepartum diet of the sows. However, the addition of butanediol to the prepartum diet increased (P less than .10) the number of pigs weaned per litter at 28 d by .51 pigs (8.17 vs 7.66) and improved (P less than .10) the survival rate of pigs from birth to weaning by 5.7 percentage units (84.1 vs 78.4%) compared with those of sows fed isocaloric additions of starch. Average pig weights at 28 d of age were similar for the two treatment groups (6.18 vs 6.08 kg) even though greater numbers of pigs were nursing sows fed the butanediol diet prepartum. The rate and efficiency of gain and survivability of weanling pigs during a 28-d postweaning period were not influenced by the prepartum diet of their dam.

  7. Enlarged test catalysts during the hydrogenation of 1,4-butynediol to 1,4-butanediol

    Directory of Open Access Journals (Sweden)

    Zhaksyntay Kairbekov

    2013-09-01

    Full Text Available The highly effective catalyzer for butynediol-1;4 hydrogenation was designed and synthesized. Enlarged tests showed that the selectivity on butanediol-1.4 at the hydrogenation of butynediol-1.4 on the alloyed catalyst SKN-39H during 320 h was 84.6 %; that on 18 % higher than for  industrial MNH. The yield of product on the catalyst SKN-39 increases slowly from 3.1 to 7.3 % when on a catalyst MNH – 7.1 to 11.7 % from the initial content of butynediol-1;4. At the hydrogenation of  butynediol on catalyst SKN-39H process efficiency increases in 1.5-2 times and product purity on 2-3 % is higher in comparing with the industrial catalyst MNH. 

  8. Conformational cooling dynamics in matrix-isolated 1,3-butanediol.

    Science.gov (United States)

    Rosado, Mário T S; Jesus, António J Lopes; Reva, Igor D; Fausto, Rui; Redinha, José S

    2009-07-02

    The complete conformational space of monomeric 1,3-butanediol has been characterized theoretically, and 73 unique stable conformers were found at the MP2/6-311++G(d,p) level. These were classified into nine families whose members share the same heavy atom backbone configurations and differ in the hydrogen atom orientations. The first and third most populated backbone families are governed by the formation of an intramolecular hydrogen bond; however, the second precludes this type of interaction and was frequently overlooked in previous studies. Its stability is determined by the relatively high entropy of its main conformers. The hydrogen bonding of four of the most important conformers was characterized by means of atoms in molecules (AIM, also known as QTAIM) and natural bond orbital (NBO) analyses. Using appropriate isodesmic reactions, hydrogen bonding energy stabilizations of 12-14 kJ mol(-1) have been found. Experimentally, monomeric molecules of 1,3-butanediol were isolated in low-temperature inert matrixes, and their infrared spectra were analyzed from the viewpoint of the conformational distribution. All the relevant transition states for the conformational interconversion reaction paths were characterized at the same level of theory to interpret the conformational cooling dynamics observed in the low-temperature matrixes. The energy barriers for rotation of the OH groups were calculated to be very low (conformers. Further increase in the substrate temperature (up to 40 K, Xe matrix) resulted in conformational cooling where the medium-height barriers (approximately 13 kJ mol(-1)) could be surmounted and all conformational population converted to the ground conformational state. Remarkably, this state turned to consist of two forms of the most stable hydrogen bonded family, which were predicted by calculations to be accidentally degenerated and were found in the annealed matrix in equal amounts. All of these experimentally observed conformational cooling

  9. An extended dynamic model of Lactococcus lactis metabolism for mannitol and 2,3-butanediol production.

    Science.gov (United States)

    Costa, Rafael S; Hartmann, Andras; Gaspar, Paula; Neves, Ana R; Vinga, Susana

    2014-03-04

    Biomedical research and biotechnological production are greatly benefiting from the results provided by the development of dynamic models of microbial metabolism. Although several kinetic models of Lactococcus lactis (a Lactic Acid Bacterium (LAB) commonly used in the dairy industry) have been developed so far, most of them are simplified and focus only on specific metabolic pathways. Therefore, the application of mathematical models in the design of an engineering strategy for the production of industrially important products by L. lactis has been very limited. In this work, we extend the existing kinetic model of L. lactis central metabolism to include industrially relevant production pathways such as mannitol and 2,3-butanediol. In this way, we expect to study the dynamics of metabolite production and make predictive simulations in L. lactis. We used a system of ordinary differential equations (ODEs) with approximate Michaelis-Menten-like kinetics for each reaction, where the parameters were estimated from multivariate time-series metabolite concentrations obtained by our team through in vivo Nuclear Magnetic Resonance (NMR). The results show that the model captures observed transient dynamics when validated under a wide range of experimental conditions. Furthermore, we analyzed the model using global perturbations, which corroborate experimental evidence about metabolic responses upon enzymatic changes. These include that mannitol production is very sensitive to lactate dehydrogenase (LDH) in the wild type (W.T.) strain, and to mannitol phosphoenolpyruvate: a phosphotransferase system (PTS(Mtl)) in a LDH mutant strain. LDH reduction has also a positive control on 2,3-butanediol levels. Furthermore, it was found that overproduction of mannitol-1-phosphate dehydrogenase (MPD) in a LDH/PTS(Mtl) deficient strain can increase the mannitol levels. The results show that this model has prediction capability over new experimental conditions and offers promising

  10. The clinical toxicology of γ-hydroxybutyrate, γ-butyrolactone and 1,4-butanediol.

    Science.gov (United States)

    Schep, Leo J; Knudsen, Kai; Slaughter, Robin J; Vale, J Allister; Mégarbane, Bruno

    2012-07-01

    Gamma-hydroxybutyrate (GHB) and its precursors, gamma-butyrolactone (GBL) and 1,4-butanediol (1,4-BD), are drugs of abuse which act primarily as central nervous system (CNS) depressants. In recent years, the rising recreational use of these drugs has led to an increasing burden upon health care providers. Understanding their toxicity is therefore essential for the successful management of intoxicated patients. We review the epidemiology, mechanisms of toxicity, toxicokinetics, clinical features, diagnosis, and management of poisoning due to GHB and its analogs and discuss the features and management of GHB withdrawal. OVID MEDLINE and ISI Web of Science databases were searched using the terms "GHB," "gamma-hydroxybutyrate," "gamma-hydroxybutyric acid," "4-hydroxybutanoic acid," "sodium oxybate," "gamma-butyrolactone," "GBL," "1,4-butanediol," and "1,4-BD" alone and in combination with the keywords "pharmacokinetics," "kinetics," "poisoning," "poison," "toxicity," "ingestion," "adverse effects," "overdose," and "intoxication." In addition, bibliographies of identified articles were screened for additional relevant studies including nonindexed reports. Non-peer-reviewed sources were also included: books, relevant newspaper reports, and applicable Internet resources. These searches produced 2059 nonduplicate citations of which 219 were considered relevant. There is limited information regarding statistical trends on world-wide use of GHB and its analogs. European data suggests that the use of GHB is generally low; however, there is some evidence of higher use among some sub-populations, settings, and geographical areas. In the United States of America, poison control center data have shown that enquiries regarding GHB have decreased between 2002 and 2010 suggesting a decline in use over this timeframe. GHB is an endogenous neurotransmitter synthesized from glutamate with a high affinity for GHB-receptors, present on both on pre- and postsynaptic neurons, thereby

  11. IMMOBILIZATION OF HUMIC ACID ONTO CHITOSAN USING TOSYLATION METHOD WITH 1,4-BUTANEDIOL AS A SPACER ARM

    Directory of Open Access Journals (Sweden)

    Uripto Trisno Santoso

    2012-02-01

    Full Text Available Immobilization of humic acid (HA onto chitosan using tosylation method with 1,4-butanediol as a spacer arm has been evaluated. Chitosan was phthaloylated selectively using phthalic anhydride in dimethylformamide as solvent with addition of 5% water (v/v as cosolvent prior to be tosylated. N-phthaloyl-chitosan and HA were tosylated using tosyl chloride in excess and triethylamine as catalyst at temperature < 10 °C for 12 h. The 6-O-tosyl-N-phthaloyl-chitosan was reacted with 1,4-butanediol in order to obtain a spacer arm attached chitosan. The 6-O-butanol-N-phthaloyl-chitosan was activated by reacting with tosyl chloride. For evaluation on immobilization of HA on chitosan with and without spacer arm, 6-O-tosylbutane-N-phthaloyl-chitosan was reacted with HA and the 6-O-tosyl-N-phthaloyl-chitosan was reacted with HA. The HA immobilized onto chitosan was characterized by XRD and FTIR spectrophotometric method. The result showed that HA can be immobilized covalently onto chitosan after attaching 1,4-butanediol as spacer arm onto 6-O-tosyl-N-phthaloyl-chitosan and activating the product with tosyl chloride, but HA cannot be reacted directly onto 6-O-tosyl-N-phthaloyl-chitosan.

  12. 2,3-Butanediol recovery from fermentation broth by alcohol precipitation and vacuum distillation.

    Science.gov (United States)

    Jeon, Sangjun; Kim, Duk-Ki; Song, Hyohak; Lee, Hee Jong; Park, Sunghoon; Seung, Doyoung; Chang, Yong Keun

    2014-04-01

    This study presents a new and effective downstream process to recover 2,3-butanediol (2,3-BD) from fermentation broth which is produced by a recombinant Klebsiella pneumoniae strain. The ldhA-deficient K. pneumoniae strain yielded about 90 g/L of 2,3-BD, along with a number of by-products, such as organic acids and alcohols, in a 65 h fed-batch fermentation. The pH-adjusted cell-free fermentation broth was firstly concentrated until 2,3-BD reached around 500 g/L by vacuum evaporation at 50°C and 50 mbar vacuum pressure. The concentrated solution was further treated using light alcohols, including methanol, ethanol, and isopropanol, for the precipitation of organic acids and inorganic salts. Isopropanol showed the highest removal efficiency, in which 92.5% and 99.8% of organic acids and inorganic salts were precipitated, respectively. At a final step, a vacuum distillation process enabled the recovery of 76.2% of the treated 2,3-BD, with 96.1% purity, indicating that fermentatively produced 2,3-BD is effectively recovered by a simple alcohol precipitation and vacuum distillation. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  13. The production of 2,3-butanediol by fermentation of high test molasses

    Energy Technology Data Exchange (ETDEWEB)

    Afschar, A.S.; Czok, A.; Schaller, K. (Gesellschaft fuer Biotechnologische Forschung mbH, Braunschweig (Germany, F.R.)); Bellgardt, K.H. (Hannover Univ. (Germany, F.R.). Inst. fuer Technische Chemie); Vaz Rossell, C.E. (Centro de Technologia Copersucar, Sao Paulo, SP (Brazil))

    1991-02-01

    Klebsiella oxytoca fermented 199 gxl{sup -1} high test or invert molasses using batch fermentation with substrate shift to produce 95.2-98.6 g 2,3-butanediolxl{sup -1} and 2,4-4.3 g acetoinxl{sup -1} with a diol yield of 96-100% of the theoretical value and a diol productivity of 1.0-1.1 gxl{sup -1}xh{sup -1}. Fermentation was performed numerous times with molasses in repeated batch culture with cell recovery. Such repeated batch fermentation, in addition to a high product yield, also showed a very high product concentration. For example, 118 g 2,3-butanediolxl{sup -1} and 2.3 g acetoinxl{sup -1} were produced from 280 gxl{sup -1} of high test molasses. The diol productivity in this fermentation amounted to 2.4 gxl{sup -1}xh{sup -1} and can undoubtedly be further increased by increasing the cell concentration. Because the Klebsiella cultures ferment 2,3-butanediol at an extremely high rate once the sugar has been consumed, the culture was inhibited completely by the addition of 15 g ethanolxl{sup -1} and switching off aeration. (orig.).

  14. Acetolactate synthase (AlsS) in Bacillus licheniformis WX-02: enzymatic properties and efficient functions for acetoin/butanediol and L-valine biosynthesis.

    Science.gov (United States)

    Huo, Yanli; Zhan, Yangyang; Wang, Qin; Li, Shunyi; Yang, Shihui; Nomura, Christopher T; Wang, Changjun; Chen, Shouwen

    2018-01-01

    Acetolactate synthase catalyzes two molecules of pyruvates to form α-acetolactate, which is further converted to acetoin and 2,3-butanediol. In this study, by heterologous expression in Escherichia coli, the enzymatic properties of acetolactate synthase (AlsS) from Bacillus licheniformis WX-02 were characterized. Its K m and k cat for pyruvate were 3.96 mM and 514/s, respectively. It has the optimal activity at pH 6.5, 37 °C and was feedback inhibited by L-valine, L-leucine and L-isoleucine. Furthermore, the alsS-deficient strain could not produce acetoin, 2,3-butanediol, and L-valine, while the complementary strain was able to restore these capacities. The alsS overexpressing strain produced higher amounts of acetoin/2,3-butanediol (57.06 g/L) and L-valine (2.68 mM), which were 10.90 and 92.80% higher than those of the control strain, respectively. This is the first report regarding the in-depth understanding of AlsS enzymatic properties and its functions in B. licheniformis, and overexpression of AlsS can effectively improve acetoin/2,3-butanediol and L-valine production in B. licheniformis. We envision that this AlsS can also be applied in the improvement of acetoin/2,3-butanediol and L-valine production in other microbes.

  15. Strategies for efficient and economical 2,3-butanediol production: new trends in this field.

    Science.gov (United States)

    Białkowska, Aneta M

    2016-12-01

    2,3-Butanediol (2,3-BD) is a promising bulk chemical with a potentially wide range of applications e.g., in the manufacture of printing inks, perfumes, synthetic rubber, fumigants, antifreeze agents, fuel additives, foodstuffs and pharmaceuticals. Its high heating value and ability to increase the octane number of fuels make 2,3-BD a promising drop-in fuel. It can also be converted to methyl-ethyl ketone (MEK), which is considered an effective liquid fuel additive. After combination with MEK and hydrogenation reaction, 2,3-BD can be converted to octane, which is used to produce high-quality aviation fuel. Currently 2,3-BD is mainly produced on an industrial scale by chemical methods. However, microbiological production of 2,3-BD offers a less expensive and more environmentally friendly alternative to traditional synthesis. This alcohol is generated from hexoses and pentoses mainly by bacterial strains of the genera Klebsiella, Bacillus, Serratia, and Enterobacter, which can convert waste products (such as glycerol and agricultural residues) and excess biomass (such as wood hydrolysates) to 2,3-BD. Recently, a significant improvement in microbial production has been achieved by the screening of efficient natural microbial strains, the application of alternative cost-effective substrates, and the genetic improvement of microbial producers. Furthermore, Klebsiella strains, which are regarded the most efficient natural 2,3-BD producers, have been subjected to genetic modifications aiming at the removal of pathogenic factors and the development of avirulent strains that could be used for the safe production of the diol. This review summarizes existing knowledge and experience concerning various strategies for efficient and economical microbial production of 2,3-BD.

  16. High Yields of 2,3-Butanediol and Mannitol in Lactococcus lactis through Engineering of NAD+ Cofactor Recycling ▿ †

    Science.gov (United States)

    Gaspar, Paula; Neves, Ana Rute; Gasson, Michael J.; Shearman, Claire A.; Santos, Helena

    2011-01-01

    Manipulation of NADH-dependent steps, and particularly disruption of the las-located lactate dehydrogenase (ldh) gene in Lactococcus lactis, is common to engineering strategies envisaging the accumulation of reduced end products other than lactate. Reverse transcription-PCR experiments revealed that three out of the four genes assigned to lactate dehydrogenase in the genome of L. lactis, i.e., the ldh, ldhB, and ldhX genes, were expressed in the parental strain MG1363. Given that genetic redundancy is often a major cause of metabolic instability in engineered strains, we set out to develop a genetically stable lactococcal host tuned for the production of reduced compounds. Therefore, the ldhB and ldhX genes were sequentially deleted in L. lactis FI10089, a strain with a deletion of the ldh gene. The single, double, and triple mutants, FI10089, FI10089ΔldhB, and FI10089ΔldhBΔldhX, showed similar growth profiles and displayed mixed-acid fermentation, ethanol being the main reduced end product. Hence, the alcohol dehydrogenase-encoding gene, the adhE gene, was inactivated in FI10089, but the resulting strain reverted to homolactic fermentation due to induction of the ldhB gene. The three lactate dehydrogenase-deficient mutants were selected as a background for the production of mannitol and 2,3-butanediol. Pathways for the biosynthesis of these compounds were overexpressed under the control of a nisin promoter, and the constructs were analyzed with respect to growth parameters and product yields under anaerobiosis. Glucose was efficiently channeled to mannitol (maximal yield, 42%) or to 2,3-butanediol (maximal yield, 67%). The theoretical yield for 2,3-butanediol was achieved. We show that FI10089ΔldhB is a valuable basis for engineering strategies aiming at the production of reduced compounds. PMID:21841021

  17. 2,3-butanediol production from Jerusalem artichoke, Helianthus tuberosus, by Bacillus polymyxa ATCC 12321. Optimization of k/sub L/ a profile

    Energy Technology Data Exchange (ETDEWEB)

    Fages, J.; Mulard, D.; Rouquet, J.J.; Wilhelm, J.L.

    1986-12-01

    Optimization of D-(-)-2,3-butanediol production from the Jerusalem artichoke, Helianthus tuberosus, by Bacillus polymyxa ATCC 12 321 is described. The effects of initial sugar concentration and oxygen transfer rate were examined. The latter appears to be the most important parameter affecting the kinetics of the process. The best results (44 g.l/sup -1/ 2,3-butanediol, productivity of 0.79 g.l/sup -1/.h/sup -1/) were obtained by setting an optimal k/sub L/a profile during batch culture.

  18. Highly Branched poly(5-amino-1-pentanol-co-1,4-butanediol diacrylate for High Performance Gene Transfection

    Directory of Open Access Journals (Sweden)

    Ming Zeng

    2017-05-01

    Full Text Available The top-performing linear poly(β-amino ester (LPAE, poly(5-amino-1-pentanol-co-1,4-butanediol diacrylate (C32, has demonstrated gene transfection efficiency comparable to viral-mediated gene delivery. Herein, we report the synthesis of a series of highly branched poly(5-amino-1-pentanol-co-1,4-butanediol diacrylate (HC32 and explore how the branching structure influences the performance of C32 in gene transfection. HC32 were synthesized by an “A2 + B3 + C2” Michal addition strategy. Gaussia luciferase (Gluciferase and green fluorescent protein (GFP coding plasmid DNA were used as reporter genes and the gene transfection efficiency was evaluated in human cervical cancer cell line (HeLa and human recessive dystrophic epidermolysis bullosa keratinocyte (RDEBK cells. We found that the optimal branching structure led to a much higher gene transfection efficiency in comparison to its linear counterpart and commercial reagents, while preserving high cell viability in both cell types. The branching strategy affected DNA binding, proton buffering capacity and degradation of polymers as well as size, zeta potential, stability, and DNA release rate of polyplexes significantly. Polymer degradation and DNA release rate played pivotal parts in achieving the high gene transfection efficiency of HC32-103 polymers, providing new insights for the development of poly(β-amino esters-based gene delivery vectors.

  19. Present state and perspective of downstream processing of biologically produced 1,3-propanediol and 2,3-butanediol.

    Science.gov (United States)

    Xiu, Zhi-Long; Zeng, An-Ping

    2008-04-01

    1,3-Propanediol and 2,3-butanediol are two promising chemicals which have a wide range of applications and can be biologically produced. The separation of these diols from fermentation broth makes more than 50% of the total costs in their microbial production. This review summarizes the present state of methods studied for the recovery and purification of biologically produced diols, with particular emphasis on 1,3-propoanediol. Previous studies on the separation of 1,3-propanediol primarily include evaporation, distillation, membrane filtration, pervaporation, ion exchange chromatography, liquid-liquid extraction, and reactive extraction. Main methods for the recovery of 2,3-butanediol include steam stripping, pervaporation, and solvent extraction. No single method has proved to be simple and efficient, and improvements are especially needed with regard to yield, purity, and energy consumption. Perspectives for an improved downstream processing of biologically produced diols, especially 1,3-propanediol are discussed based on our own experience and recent work. It is argued that separation technologies such as aqueous two-phase extraction with short chain alcohols, pervaporation, reverse osmosis, and in situ extractive or pervaporative fermentations deserve more attention in the future.

  20. Liquid-liquid equilibrium data for the separation of 2,3-butanediol from aqueous streams using tetraoctyl ammonium 2-methyl-1-naphthoate

    NARCIS (Netherlands)

    Garcia Chavez, L.Y.; Shazad, M.; Schuur, Boelo; de Haan, A.B.

    2012-01-01

    Microbiological production of 2,3-butanediol (2,3-BD) through fermentation using renewable feedstock is a promising option for the production of bio based chemicals. Liquid–liquid extraction could be a more efficient process, if a proper solvent is used. Tetraoctyl ammonium 2-methyl-1-naphthoate

  1. Synthesis of 2,3-butanediol by Synechocystis sp. PCC6803 via heterologous expression of a catabolic pathway from lactic acid- and enterobacteria.

    NARCIS (Netherlands)

    Savakis, P.E.; Angermayr, S.; Hellingwerf, K.

    2013-01-01

    The direct and efficient conversion of CO2 into liquid energy carriers and/or bulk chemicals is crucial for a sustainable future of modern society. Here we describe the production of 2,3-butanediol in Synechocystis sp. PCC6803 expressing a heterologous catabolic pathway derived from enteric- and

  2. A novel strategy for integrated utilization of Jerusalem artichoke stalk and tuber for production of 2,3-butanediol by Klebsiella pneumoniae.

    Science.gov (United States)

    Li, Dan; Dai, Jian-Ying; Xiu, Zhi-Long

    2010-11-01

    Jerusalem artichoke stalk and tuber can serve as a low cost feedstock for the production of 2,3-butanediol. However, like other lignocellulosic materials, the sugar concentration in the hydrolysate prepared from Jerusalem artichoke stalk is too low to be utilized effectively by microorganisms. In this paper a novel strategy was proposed to increase the sugar concentration by adding Jerusalem artichoke tuber into the hydrolysate of the stalk. The sugar was then biotransformed into high-valued 2,3-butanediol by Klebsiella pneumoniae. Fed-batch simultaneous saccharification and fermentation (SSF) was effectively performed and 901.2 mmol/l (80.5 g/l) target products (2,3-butanediol plus acetoin) was obtained in 68 h by a stage-shift aeration strategy. The concentration, yield and productivity of target products were 16.9%, 16.8% and 23.4%, respectively, higher than the best results obtained with SSF operated under constant aeration. This showed that adding tuber to the stalk hydrolysate was a useful strategy for increasing the production of 2,3-butanediol from Jerusalem artichoke via fermentation. Copyright 2010 Elsevier Ltd. All rights reserved.

  3. Techno-economic evaluation of a complete bioprocess for 2,3-butanediol production from renewable resources.

    Science.gov (United States)

    Koutinas, Apostolis A; Yepez, Bernardo; Kopsahelis, Nikolaos; Freire, Denise M G; de Castro, Aline Machado; Papanikolaou, Seraphim; Kookos, Ioannis K

    2016-03-01

    This study presents the techno-economic evaluation of 2,3-butanediol (BDO) production via fermentation using glycerol, sucrose and sugarcane molasses as carbon sources. Literature-cited experimental data were used to design the fermentation stage, whereas downstream separation of BDO was based on reactive extraction of BDO employing an aldehyde to convert BDO into an acetal that is immiscible with water. The selected downstream process can be used in all fermentations employed. Sensitivity analysis was carried out targeting the estimation of the minimum selling price (MSP) of BDO at different plant capacities and raw material purchase costs. In all cases, the MSP of BDO is higher than 1 $/kg that is considered as the target in order to characterize a fermentation product as platform chemical. The complex nutrient supplements, the raw material market price and the fermentation efficiency were identified as the major reasons for the relatively high MSP observed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Systematic investigations on the reduction of 4-aryl-4-oxoesters to 1-aryl-1,4-butanediols with methanolic sodium borohydride

    Directory of Open Access Journals (Sweden)

    Subrata Kumar Chaudhuri

    2010-09-01

    Full Text Available 4-Aryl-4-oxoesters undergo facile reduction of both the keto and the ester groups with methanolic NaBH4 at room temperature to yield the corresponding 1-aryl-1,4-butanediols whereas 4-alkyl-4-oxoesters furnish the corresponding 1,4-butanolides via selective reduction of the keto moiety. Results of a detailed and systematic investigation of the reaction are described.

  5. Synthesis and crystallographic analysis of meso-2,3-difluoro-1,4-butanediol and meso-1,4-dibenzyloxy-2,3-difluorobutane

    Directory of Open Access Journals (Sweden)

    Bruno Linclau

    2010-06-01

    Full Text Available A large-scale synthesis of meso-2,3-difluoro-1,4-butanediol in 5 steps from (Z-but-2-enediol is described. Crystallographic analysis of the diol and the corresponding benzyl ether reveals an anti conformation of the vicinal difluoride moiety. Monosilylation of the diol is high-yielding but all attempts to achieve chain extension through addition of alkyl Grignard and acetylide nucleophiles failed.

  6. Development of an industrial medium for economical 2,3-butanediol production through co-fermentation of glucose and xylose by Klebsiella oxytoca.

    Science.gov (United States)

    Ji, Xiao-Jun; Huang, He; Du, Jun; Zhu, Jian-Guo; Ren, Lu-Jing; Li, Shuang; Nie, Zhi-Kui

    2009-11-01

    An industrial medium containing urea as a sole nitrogen source, low levels of corn steep liquor and mineral salts as nutrition factors to retain high 2,3-butanediol production through co-fermentation of glucose and xylose (2:1, wt/wt) by Klebsiella oxytoca was developed. Urea and corn steep liquor were identified as the most significant factors by the two-level Plackett-Burman design. Steepest ascent experiments were applied to approach the optimal region of the two factors and a central composite design was employed to determine their optimal levels. Under the optimal medium, the yield of 2,3-butanediol plus acetoin relative to glucose and xylose was up to 0.428 g/g, which was 85.6% of theoretical value. The cheap nitrogen source and nutrition factors combining the co-fermentation process using lignocellulose derived glucose and xylose as the carbon source in the developed medium would be a potential solution to improve the economics of microbial 2,3-butanediol production.

  7. Efficient Simultaneous Saccharification and Fermentation of Inulin to 2,3-Butanediol by Thermophilic Bacillus licheniformis ATCC 14580

    Science.gov (United States)

    Li, Lixiang; Chen, Chao; Li, Kun; Wang, Yu; Gao, Chao; Ma, Cuiqing

    2014-01-01

    2,3-Butanediol (2,3-BD) is an important starting material for the manufacture of bulk chemicals. For efficient and large-scale production of 2,3-BD through fermentation, low-cost substrates are required. One such substrate, inulin, is a polydisperse fructan found in a wide variety of plants. In this study, a levanase with high inulinase activity and high pH and temperature stability was identified in Bacillus licheniformis strain ATCC 14580. B. licheniformis strain ATCC 14580 was found to efficiently produce 2,3-BD from fructose at 50°C. Then, the levanase was used for simultaneous saccharification and fermentation (SSF) of inulin to 2,3-BD. A fed-batch SSF yielded 103.0 g/liter 2,3-BD in 30 h, with a high productivity of 3.4 g/liter · h. The results suggest that the SSF process developed with the thermophilic B. licheniformis strain used might be a promising alternative for efficient 2,3-BD production from the favorable substrate inulin. PMID:25107977

  8. LCA of 1,4-Butanediol Produced via Direct Fermentation of Sugars from Wheat Straw Feedstock within a Territorial Biorefinery

    Directory of Open Access Journals (Sweden)

    Annachiara Forte

    2016-07-01

    Full Text Available The bio-based industrial sector has been recognized by the European Union as a priority area toward sustainability, however, the environmental profile of bio-based products needs to be further addressed. This study investigated, through the Life Cycle Assessment (LCA approach, the environmental performance of bio-based 1,4-butanediol (BDO produced via direct fermentation of sugars from wheat straw, within a hypothetical regional biorefinery (Campania Region, Southern Italy. The aim was: (i to identify the hotspots along the production chain; and (ii to assess the potential environmental benefits of this bio-based polymer versus the reference conventional product (fossil-based BDO. Results identified the prevailing contribution to the total environmental load of bio-based BDO in the feedstock production and in the heat requirement at the biorefinery plant. The modeled industrial bio-based BDO supply chain, showed a general reduction of the environmental impacts compared to the fossil-based BDO. The lowest benefits were gained in terms of acidification and eutrophication, due to the environmental load of the crop phase for feedstock cultivation.

  9. Two-stage pH control strategy based on the pH preference of acetoin reductase regulates acetoin and 2,3-butanediol distribution in Bacillus subtilis.

    Science.gov (United States)

    Zhang, Xian; Bao, Teng; Rao, Zhiming; Yang, Taowei; Xu, Zhenghong; Yang, Shangtian; Li, Huazhong

    2014-01-01

    Acetoin reductase/2,3-butanediol dehydrogenase (AR/BDH), which catalyzes the interconversion between acetoin and 2,3-butanediol, plays an important role in distribution of the products pools. This work characterized the Bacillus subtilis AR/BDH for the first time. The enzyme showed very different pH preferences of pH 6.5 for reduction and pH 8.5 for oxidation. Based on these above results, a two-stage pH control strategy was optimized for acetoin production, in which the pH was controlled at 6.5 for quickly converting glucose to acetoin and 2,3-butanediol, and then 8.0 for reversely transforming 2,3-butanediol to acetoin. By over-expression of AR/BDH in the wild-type B. subtilis JNA 3-10 and applying fed-batch fermentation based on the two-stage pH control strategy, acetoin yield of B. subtilis was improved to a new record of 73.6 g/l, with the productivity of 0.77 g/(l · h). The molar yield of acetoin was improved from 57.5% to 83.5% and the ratio of acetoin/2,3-butanediol was switched from 2.7:1 to 18.0:1.

  10. Two-stage pH control strategy based on the pH preference of acetoin reductase regulates acetoin and 2,3-butanediol distribution in Bacillus subtilis.

    Directory of Open Access Journals (Sweden)

    Xian Zhang

    Full Text Available Acetoin reductase/2,3-butanediol dehydrogenase (AR/BDH, which catalyzes the interconversion between acetoin and 2,3-butanediol, plays an important role in distribution of the products pools. This work characterized the Bacillus subtilis AR/BDH for the first time. The enzyme showed very different pH preferences of pH 6.5 for reduction and pH 8.5 for oxidation. Based on these above results, a two-stage pH control strategy was optimized for acetoin production, in which the pH was controlled at 6.5 for quickly converting glucose to acetoin and 2,3-butanediol, and then 8.0 for reversely transforming 2,3-butanediol to acetoin. By over-expression of AR/BDH in the wild-type B. subtilis JNA 3-10 and applying fed-batch fermentation based on the two-stage pH control strategy, acetoin yield of B. subtilis was improved to a new record of 73.6 g/l, with the productivity of 0.77 g/(l · h. The molar yield of acetoin was improved from 57.5% to 83.5% and the ratio of acetoin/2,3-butanediol was switched from 2.7:1 to 18.0:1.

  11. Lysate of engineered Escherichia coli supports high-level conversion of glucose to 2,3-butanediol.

    Science.gov (United States)

    Kay, Jennifer E; Jewett, Michael C

    2015-11-01

    Cell-free metabolic engineering (CFME) is emerging as a powerful approach for the production of target molecules and pathway debugging. Unfortunately, high cofactor costs, limited cofactor and energy regeneration, and low volumetric productivities hamper the widespread use and practical implementation of CFME technology. To address these challenges, we have developed a cell-free system that harnesses ensembles of catalytic proteins prepared from crude lysates, or extracts, of cells to fuel highly active heterologous metabolic conversions. As a model pathway, we selected conversion of glucose to 2,3-butanediol (2,3-BD), a medium level commodity chemical with many industrial applications. Specifically, we engineered a single strain of Escherichia coli to express three pathway enzymes necessary to make meso-2,3-BD (m2,3-BD). We then demonstrated that lysates from this strain, with addition of glucose and catalytic amounts of cofactors NAD+ and ATP, can produce m2,3-BD. Endogenous glycolytic enzymes convert glucose to pyruvate, the starting intermediate for m2,3-BD synthesis. Strikingly, with no strain optimization, we observed a maximal synthesis rate of m2,3-BD of 11.3 ± 0.1 g/L/h with a theoretical yield of 71% (0.36 g m2,3-BD/g glucose) in batch reactions. Titers reached 82 ± 8 g/L m2,3-BD in a 30 h fed-batch reaction. Our results highlight the ability for high-level co-factor regeneration in cell-free lysates. Further, they suggest exciting opportunities to use lysate-based systems to rapidly prototype metabolic pathways and carry out molecular transformations when bioconversion yields (g product/L), productivities (g product/L/h), or cellular toxicity limit commercial feasibility of whole-cell fermentation. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  12. Metabolic engineering of a Saccharomyces cerevisiae strain capable of simultaneously utilizing glucose and galactose to produce enantiopure (2R,3R)-butanediol.

    Science.gov (United States)

    Lian, Jiazhang; Chao, Ran; Zhao, Huimin

    2014-05-01

    2,3-Butanediol (BDO) is an important chemical with broad industrial applications and can be naturally produced by many bacteria at high levels. However, the pathogenicity of these native producers is a major obstacle for large scale production. Here we report the engineering of an industrially friendly host, Saccharomyces cerevisiae, to produce BDO at high titer and yield. By inactivation of pyruvate decarboxylases (PDCs) followed by overexpression of MTH1 and adaptive evolution, the resultant yeast grew on glucose as the sole carbon source with ethanol production completely eliminated. Moreover, the pdc- strain consumed glucose and galactose simultaneously, which to our knowledge is unprecedented in S. cerevisiae strains. Subsequent introduction of a BDO biosynthetic pathway consisting of the cytosolic acetolactate synthase (cytoILV2), Bacillus subtilis acetolactate decarboxylase (BsAlsD), and the endogenous butanediol dehydrogenase (BDH1) resulted in the production of enantiopure (2R,3R)-butanediol (R-BDO). In shake flask fermentation, a yield over 70% of the theoretical value was achieved. Using fed-batch fermentation, more than 100g/L R-BDO (1100mM) was synthesized from a mixture of glucose and galactose, two major carbohydrate components in red algae. The high titer and yield of the enantiopure R-BDO produced as well as the ability to co-ferment glucose and galactose make our engineered yeast strain a superior host for cost-effective production of bio-based BDO from renewable resources. Copyright © 2014 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  13. Dynamic polarization of protons in 2,3-butanediol doped with Cr(V)- complex and in other materials containing adjacent hydroxyl groups

    CERN Document Server

    Guckelsberger, K

    1977-01-01

    Results are given on 2,3-butanediol doped with Cr(V)-complex as a material for polarized proton targets. It is shown to be an improvement over the presently used 1,2-propanediol since its chemical composition is slightly more favourable and its melting point is near room temperature. Maximum polarization, nuclear relaxation time, reversal time, minimum power requirement, radiation resistance, and annealing temperature are all very similar to 1,2-propanediol. A review of other materials containing adjacent hydroxyl groups is made, and conclusions are drawn as to their possible use as target materials. (17 refs).

  14. Production of (2R, 3R)-2,3-butanediol using engineeredPichia pastoris: strain construction, characterization and fermentation.

    Science.gov (United States)

    Yang, Zhiliang; Zhang, Zisheng

    2018-01-01

    2,3-butanediol (2,3-BD) is a bulk platform chemical with various potential applications such as aviation fuel. 2,3-BD has three optical isomers: (2R, 3R)-, (2S, 3S)- and meso-2,3-BD. Optically pure 2,3-BD is a crucial precursor for the chiral synthesis and it can also be used as anti-freeze agent due to its low freezing point. 2,3-BD has been produced in both native and non-native hosts. Several pathogenic bacteria were reported to produce 2,3-BD in mixture of its optical isomers including Klebsiella pneumoniae and Klebsiella oxytoca . Engineered hosts based on episomal plasmid expression such as Escherichia coli , Saccharomyces cerevisiae and Bacillus subtilis are not ideal for industrial fermentation due to plasmid instability. Pichia pastoris is generally regarded as safe and a well-established host for high-level heterologous protein production. To produce pure (2R, 3R)-2,3-BD enantiomer, we developed a P. pastoris strain by introducing a synthetic pathway. The als S and als D genes from B. subtilis were codon-optimized and synthesized. The BDH1 gene from S. cerevisiae was cloned. These three pathway genes were integrated into the genome of P. pastoris and expressed under the control of GAP promoter. Production of (2R, 3R)-2,3-BD was achieved using glucose as feedstock. The optical purity of (2R, 3R)-2,3-BD was more than 99%. The titer of (2R, 3R)-2,3-BD reached 12 g/L with 40 g/L glucose as carbon source in shake flask fermentation. The fermentation conditions including pH, agitation speeds and aeration rates were optimized in batch cultivations. The highest titer of (2R, 3R)-2,3-BD achieved in fed-batch fermentation using YPD media was 45 g/L. The titer of 2,3-BD was enhanced to 74.5 g/L through statistical medium optimization. The potential of engineering P. pastoris into a microbial cell factory for biofuel production was evaluated in this work using (2R, 3R)-2,3-BD as an example. Engineered P. pastoris could be a promising workhorse for the production

  15. Novel Aldo-Keto Reductases for the Biocatalytic Conversion of 3-Hydroxybutanal to 1,3-Butanediol: Structural and Biochemical Studies

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Taeho; Flick, Robert; Brunzelle, Joseph; Singer, Alex; Evdokimova, Elena; Brown, Greg; Joo, Jeong Chan; Minasov, George A.; Anderson, Wayne F.; Mahadevan, Radhakrishnan; Savchenko, Alexei; Yakunin, Alexander F. (KRICT); (Toronto); (NWU)

    2017-01-27

    The nonnatural alcohol 1,3-butanediol (1,3-BDO) is a valuable building block for the synthesis of various polymers. One of the potential pathways for the biosynthesis of 1,3-BDO includes the biotransformation of acetaldehyde to 1,3-BDO via 3-hydroxybutanal (3-HB) using aldolases and aldo-keto reductases (AKRs). This pathway requires an AKR selective for 3-HB, but inactive toward acetaldehyde, so it can be used for one-pot synthesis. In this work, we screened more than 20 purified uncharacterized AKRs for 3-HB reduction and identified 10 enzymes with significant activity and nine proteins with detectable activity. PA1127 fromPseudomonas aeruginosashowed the highest activity and was selected for comparative studies with STM2406 fromSalmonella entericaserovar Typhimurium, for which we have determined the crystal structure. Both AKRs used NADPH as a cofactor, reduced a broad range of aldehydes, and showed low activities toward acetaldehyde. The crystal structures of STM2406 in complex with cacodylate or NADPH revealed the active site with bound molecules of a substrate mimic or cofactor. Site-directed mutagenesis of STM2406 and PA1127 identified the key residues important for the activity against 3-HB and aromatic aldehydes, which include the residues of the substrate-binding pocket and C-terminal loop. Our results revealed that the replacement of the STM2406 Asn65 by Met enhanced the activity and the affinity of this protein toward 3-HB, resulting in a 7-fold increase inkcat/Km. Our work provides further insights into the molecular mechanisms of the substrate selectivity of AKRs and for the rational design of these enzymes toward new substrates.

    IMPORTANCEIn this study, we identified several aldo-keto reductases with significant activity in reducing 3

  16. Enzymatic hydrolysis and simultaneous saccharification and fermentation of alkali/peracetic acid-pretreated sugarcane bagasse for ethanol and 2,3-butanediol production.

    Science.gov (United States)

    Zhao, Xuebing; Song, Yuanquan; Liu, Dehua

    2011-09-10

    The enzymatic digestibility of alkali/peracetic acid (PAA)-pretreated bagasse was systematically investigated. The effects of initial solid consistency, cellulase loading and addition of supplemental β-glucosidase on the enzymatic conversion of glycan were studied. It was found the alkali-PAA pulp showed excellent enzymatic digestibility. The enzymatic glycan conversion could reach about 80% after 24 h incubation when enzyme loading was 10 FPU/g solid. Simultaneous saccharification and fermentation (SSF) results indicated that the pulp could be well converted to ethanol. Compared with dilute acid pretreated bagasse (DAPB), alkali-PAA pulp could obtain much higher ethanol and xylose concentrations. The fermentation broth still showed some cellulase activity so that the fed pulp could be further converted to sugars and ethanol. After the second batch SSF, the fermentation broth of alkali-PAA pulp still kept about 50% of initial cellulase activity. However, only 21% of initial cellulase activity was kept in the fermentation broth of DAPB. The xylose syrup obtained in SSF of alkali-PAA pulp could be well converted to 2,3-butanediol by Klebsiella pneumoniae CGMCC 1.9131. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Process Optimization on Micro-Aeration Supply for High Production Yield of 2,3-Butanediol from Maltodextrin by Metabolically-Engineered Klebsiella oxytoca.

    Directory of Open Access Journals (Sweden)

    Sitha Chan

    Full Text Available An optimization process with a cheap and abundant substrate is considered one of the factors affecting the price of the production of economical 2,3-Butanediol (2,3-BD. A combination of the conventional method and response surface methodology (RSM was applied in this study. The optimized levels of pH, aeration rate, agitation speed, and substrate concentration (maltodextrin were investigated to determine the cost-effectiveness of fermentative 2,3-BD production by metabolically-engineered Klebsiella oxytoca KMS005. Results revealed that pH, aeration rate, agitation speed, and maltodextrin concentration at levels of 6.0, 0.8 vvm, 400 rpm, and 150 g/L respectively were the optimal conditions. RSM also indicated that the agitation speed was the most influential parameter when either agitation and aeration interaction or agitation and substrate concentration interaction played important roles for 2,3-BD production by the strain from maltodextrin. Under interim fed-batch fermentation, 2,3-BD concentration, yield, and productivity were obtained at 88.1±0.2 g/L, 0.412±0.001 g/g, and 1.13±0.01 g/L/h respectively within 78 h.

  18. Efficacy and Safety of Sodium Hyaluronate with 1,4-Butanediol Diglycidyl Ether Compared to Sodium Carboxymethylcellulose in Preventing Adhesion Formation after Lumbar Discectomy.

    Science.gov (United States)

    Ji, Gyu Yeul; Oh, Chang Hyun; Moon, Byung Gwan; Yi, Seong; Han, In Bo; Heo, Dong Hwa; Kim, Ki-Tack; Shin, Dong Ah; Kim, Keung Nyun

    2015-06-01

    Epidural injection of hyaluronic acid may prevent adhesion formation after spine surgery, but the compounds used to stabilize hyaluronidase could interfere with its anti-adhesion effects. The present study was conducted as a clinical trial to evaluate the efficacy and safety of an experimental medical gel in preventing adhesion formation. This study was designed as a multicenter, randomized, double-blind, and comparative controlled clinical trial with an observation period of 6 weeks. Subjects were randomly assigned into two groups: group A with sodium hyaluronate + 1,4-butanediol diglycidyl ether (BDDE) and group B with sodium hyaluronate + sodium carboxymethylcellulose (CMC). Visual analogue scale (VAS) of back and leg pain and the Oswestry disability index (ODI) and scar score ratings were assessed after surgery. Mean scar grade was 2.37±1.13 in group A and 2.75±0.97 in group B, a statistically significant difference (p=0.012). VAS of back and leg pain and ODI scores decreased significantly from baseline to 3 and 6 weeks postoperatively in both groups (p0.3). The number of adverse reactions related to the anti-adhesion gels was not statistically different (p=0.569), but subsequent analysis of nervous adverse reactions showed group B was superior with a statistically difference (p=0.027). Sodium hyaluronate with BDDE demonstrated similar anti-adhesion properties to sodium hyaluronate with CMC. But, care should be used to nervous adverse reactions by using sodium hyaluronate with BDDE.

  19. Effects of mutation of 2,3-butanediol formation pathway on glycerol metabolism and 1,3-propanediol production by Klebsiella pneumoniae J2B.

    Science.gov (United States)

    Kumar, Vinod; Durgapal, Meetu; Sankaranarayanan, Mugesh; Somasundar, Ashok; Rathnasingh, Chelladurai; Song, HyoHak; Seung, Doyoung; Park, Sunghoon

    2016-08-01

    The current study investigates the impact of mutation of 2,3-butanediol (BDO) formation pathway on glycerol metabolism and 1,3-propanediol (PDO) production by lactate dehydrogenase deficient mutant of Klebsiella pneumoniae J2B. To this end, BDO pathway genes, budA, budB, budC and budO (whole-bud operon), were deleted from K. pneumoniae J2B ΔldhA and the mutants were studied for glycerol metabolism and alcohols (PDO, BDO) production. ΔbudO-mutant-only could completely abolish BDO production, but with reductions in cell growth and PDO production. By modifying the culture medium, the ΔbudO mutant could recover its performance on the flask scale. However, in bioreactor experiments, the ΔbudO mutant accumulated a significant amount of pyruvate (>73mM) in the late phase and PDO production stopped concomitantly. Glycolytic intermediates of glycerol, especially glyceraldehyde-3-phosphate (G3P) was highly inhibitory to glycerol dehydratase (GDHt); its accumulation, followed by pyruvate accumulation, was assumed to be responsible for the ΔbudO mutant's low PDO production. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Conversion of succinic acid to 1,4-butanediol via dimethyl succinate over rhenium nano-catalyst supported on copper-containing mesoporous carbon.

    Science.gov (United States)

    Hong, Ung Gi; Kim, Jeong Kwon; Lee, Joongwon; Lee, Jong Kwon; Yi, Jongheop; Song, In Kyu

    2014-11-01

    Copper-containing mesoporous carbons (XCu-MC) with different copper content (X = 8.0, 12.7, 15.9, 23.3, and 26.8 wt%) were prepared by a single-step surfactant-templating method. Rhenium nano-catalysts supported on copper-containing mesoporous carbons (Re/XCu-MC) were then prepared by an incipient wetness method. Re/XCu-MC (X = 8.0, 12.7, 15.9, 23.3, and 26.8 wt%) catalysts were characterized by nitrogen adsorption-desorption isotherm, HR-TEM, FT-IR, and H2- TPR analyses. Liquid-phase hydrogenation of succinic acid to 1,4-butanediol (BDO) via dimethyl succinate (DMS) was carried out over Re/XCu-MC catalysts in a batch reactor. The effect of copper content on the physicochemical properties and catalytic activities of Re/XCu-MC catalysts in the hydrogenation of succinic acid to BDO was investigated. Re/XCu-MC catalysts retained different physicochemical properties depending on copper content. In the hydrogenation of succinic acid to BDO, yield for BDO showed a volcano-shaped trend with respect to copper content. Thus, an optimal copper content was required to achieve maximum catalytic performance of Re/XCu-MC. It was also observed that yield for BDO increased with increasing the amount of hydrogen consumption by copper in the Re/XCu-MC catalysts.

  1. Enhancement of 2,3-butanediol production from Jerusalem artichoke tuber extract by a recombinant Bacillus sp. strain BRC1 with increased inulinase activity.

    Science.gov (United States)

    Park, Jang Min; Oh, Baek-Rock; Kang, In Yeong; Heo, Sun-Yeon; Seo, Jeong-Woo; Park, Seung-Moon; Hong, Won-Kyung; Kim, Chul Ho

    2017-07-01

    A Bacillus sp. strain named BRC1 is capable of producing 2,3-butanediol (2,3-BD) using hydrolysates of the Jerusalem artichoke tuber (JAT), a rich source of the fructose polymer inulin. To enhance 2,3-BD production, we undertook an extensive analysis of the Bacillus sp. BRC1 genome, identifying a putative gene (sacC) encoding a fructan hydrolysis enzyme and characterizing the activity of the resulting recombinant protein expressed in and purified from Escherichia coli. Introduction of the sacC gene into Bacillus sp. BRC1 using an expression vector increased enzymatic activity more than twofold. Consistent with this increased enzyme expression, 2,3-BD production from JAT was also increased from 3.98 to 8.10 g L-1. Fed-batch fermentation of the recombinant strain produced a maximal level of 2,3-BD production of 28.6 g L-1, showing a high theoretical yield of 92.3%.

  2. Research on the Solid State Fermentation of Jerusalem Artichoke Pomace for Producing R,R-2,3-Butanediol by Paenibacillus polymyxa ZJ-9.

    Science.gov (United States)

    Cao, Can; Zhang, Li; Gao, Jian; Xu, Hong; Xue, Feng; Huang, Weiwei; Li, Yan

    2017-06-01

    R,R-2,3-butanediol (R,R-2,3-BD) was produced by Paenibacillus polymyxa ZJ-9, which was capable of utilizing inulin without previous hydrolysis. The Jerusalem artichoke pomace (JAP) derived from the conversion of Jerusalem artichoke powder into inulin extract, which was usually used for biorefinery by submerged fermentation (SMF), was utilized in solid state fermentation (SSF) to produce R,R-2,3-BD. In this study, the fermentation parameters of SSF were optimized and determined in flasks. A novel bioreactor was designed and assembled for the laboratory scale-up of SSF, with a maximum yield of R,R-2,3-BD (67.90 g/kg (JAP)). This result is a 36.3% improvement compared with the flasks. Based on the same bath of Jerusalem artichoke powder, the total output of R,R-2,3-BD increased by 38.8% for the SSF of JAP combined with the SMF of inulin extraction. Overall, the utilization of JAP for R,R-2,3-BD production was beneficial to the comprehensive utilization of Jerusalem artichoke tuber.

  3. Enhanced 2,3-Butanediol Production by Optimizing Fermentation Conditions and Engineering Klebsiella oxytoca M1 through Overexpression of Acetoin Reductase.

    Directory of Open Access Journals (Sweden)

    Sukhyeong Cho

    Full Text Available Microbial production of 2,3-butanediol (2,3-BDO has been attracting increasing interest because of its high value and various industrial applications. In this study, high production of 2,3-BDO using a previously isolated bacterium Klebsiella oxytoca M1 was carried out by optimizing fermentation conditions and overexpressing acetoin reductase (AR. Supplying complex nitrogen sources and using NaOH as a neutralizing agent were found to enhance specific production and yield of 2,3-BDO. In fed-batch fermentations, 2,3-BDO production increased with the agitation speed (109.6 g/L at 300 rpm vs. 118.5 g/L at 400 rpm along with significantly reduced formation of by-product, but the yield at 400 rpm was lower than that at 300 rpm (0.40 g/g vs. 0.34 g/g due to acetoin accumulation at 400 rpm. Because AR catalyzing both acetoin reduction and 2,3-BDO oxidation in K. oxytoca M1 revealed more than 8-fold higher reduction activity than oxidation activity, the engineered K. oxytoca M1 overexpressing the budC encoding AR was used in fed-batch fermentation. Finally, acetoin accumulation was significantly reduced by 43% and enhancement of 2,3-BDO concentration (142.5 g/L, yield (0.42 g/g and productivity (1.47 g/L/h was achieved compared to performance with the parent strain. This is by far the highest titer of 2,3-BDO achieved by K. oxytoca strains. This notable result could be obtained by finding favorable fermentation conditions for 2,3-BDO production as well as by utilizing the distinct characteristic of AR in K. oxytoca M1 revealing the nature of reductase.

  4. Evaluation of MC3T3 Cells Proliferation and Drug Release Study from Sodium Hyaluronate-1,4-butanediol Diglycidyl Ether Patterned Gel.

    Science.gov (United States)

    Bang, Sumi; Das, Dipankar; Yu, Jiyun; Noh, Insup

    2017-10-14

    A pattern gel has been fabricated using sodium hyaluronate (HA) and 1,4-butanediol diglycidyl ether (BDDGE) through the micro-molding technique. The cellular behavior of osteoblast cells (MC3T3) in the presence and absence of dimethyloxalylglycine (DMOG) and sodium borate (NaB) in the pattern gel (HA-BDDGE) has been evaluated for its potential application in bone regeneration. The Fourier transform infrared spectroscopy (FTIR), 13C-nuclear magnetic resonance spectroscopy (13C NMR), and thermogravimetric analysis (TGA) results implied the crosslinking reaction between HA and BDDGE. The scanning electron microscopy (SEM) analysis confirmed the formation of pattern on the surface of HA-BDDGE. The gel property of the crosslinked HA-BDDGE has been investigated by swelling study in distilled water at 37 °C. The HA-BDDGE gel releases DMOG in a controlled way for up to seven days in water at 37 °C. The synthesized gel is biocompatible and the bolus drug delivery results indicated that the DMOG containing patterned gel demonstrates a better cell migration ability on the surface than NaB. For local delivery, the pattern gel with 300 µM NaB or 300 µM DMOG induced cell clusters formation, and the gel with 150 µM NaB/DMOG showed high cell proliferation capability only. The vital role of NaB for bone regeneration has been endorsed from the formation of cell clusters in presence of NaB in the media. The in vitro results indicated that the pattern gel showed angiogenic and osteogenic responses with good ALP activity and enhanced HIF-1α, and Runx2 levels in the presence of DMOG and NaB in MC3T3 cells. Hence, the HA-BDDGE gel could be used in bone regeneration application.

  5. Influence of blocking of 2,3-butanediol pathway on glycerol metabolism for 1,3-propanediol production by Klebsiella oxytoca.

    Science.gov (United States)

    Zhang, Gang; Yang, Guang; Wang, Xu; Guo, Qingjuan; Li, Ying; Li, Jilun

    2012-09-01

    Glycerol metabolism is a typical biological oxidoreductive reaction. 1,3-Propanediol (1,3-PD) is the final product of the reductive branch, while acetate, succinate, lactate, 2,3-butanediol (2,3-BD), and ethanol were produced in the oxidative branch. 2,3-BD, which has similar properties of high boiling point and water solubility with 1,3-PD, not only contests the carbon flow and NADH with 1,3-PD but also serves as an obstacle for obtaining high purity 1,3-PD in downstream processes. In this study, a 2,3-BD pathway-deficient mutant of Klebsiella oxytoca ZG36 was constructed by knocking out the budA gene of the wild-type strain M5al. The results of fed-batch fermentation by ZG36 indicated that the glycerol flux and the distribution of metabolites were altered in the K. oxytoca when the 2,3-BD pathway was blocked. No 2,3-BD was produced, and the activity of α-acetolactate decarboxylase (α-ALDC) can not be detected in the fermentation processes. The indexes of the 1,3-PD titer, the conversion from glycerol to 1,3-PD, and the productivity per cell dry weight (CDW) increased by 42%, 62%, and 46%, respectively, compared with the M5al, and the yield of the byproducts also increased obviously. The assay of the enzyme activities in the oxidative branch and the reductive branch of the glycerol metabolism, as well as the intracellular redox state, exposited the results logically.

  6. 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)

  7. Efficient whole-cell biocatalyst for acetoin production with NAD+ regeneration system through homologous co-expression of 2,3-butanediol dehydrogenase and NADH oxidase in engineered Bacillus subtilis.

    Directory of Open Access Journals (Sweden)

    Teng Bao

    Full Text Available Acetoin (3-hydroxy-2-butanone, an extensively-used food spice and bio-based platform chemical, is usually produced by chemical synthesis methods. With increasingly requirement of food security and environmental protection, bio-fermentation of acetoin by microorganisms has a great promising market. However, through metabolic engineering strategies, the mixed acid-butanediol fermentation metabolizes a certain portion of substrate to the by-products of organic acids such as lactic acid and acetic acid, which causes energy cost and increases the difficulty of product purification in downstream processes. In this work, due to the high efficiency of enzymatic reaction and excellent selectivity, a strategy for efficiently converting 2,3-butandiol to acetoin using whole-cell biocatalyst by engineered Bacillus subtilis is proposed. In this process, NAD+ plays a significant role on 2,3-butanediol and acetoin distribution, so the NADH oxidase and 2,3-butanediol dehydrogenase both from B. subtilis are co-expressed in B. subtilis 168 to construct an NAD+ regeneration system, which forces dramatic decrease of the intracellular NADH concentration (1.6 fold and NADH/NAD+ ratio (2.2 fold. By optimization of the enzymatic reaction and applying repeated batch conversion, the whole-cell biocatalyst efficiently produced 91.8 g/L acetoin with a productivity of 2.30 g/(L·h, which was the highest record ever reported by biocatalysis. This work indicated that manipulation of the intracellular cofactor levels was more effective than the strategy of enhancing enzyme activity, and the bioprocess for NAD+ regeneration may also be a useful way for improving the productivity of NAD+-dependent chemistry-based products.

  8. Determination of γ-hydroxybutyrate (GHB), β-hydroxybutyrate (BHB), pregabalin, 1,4-butane-diol (1,4BD) and γ-butyrolactone (GBL) in whole blood and urine samples by UPLC-MSMS.

    Science.gov (United States)

    Dahl, Sandra Rinne; Olsen, Kirsten Midtbøen; Strand, Dag Helge

    2012-02-15

    The demand of high throughput methods for the determination of gamma-hydroxybutyrate (GHB) and its precursors gamma-butyrolactone (GBL) and 1,4-butane-diol (1,4BD) as well as for pregabalin is increasing. Here we present two analytical methods using ultra-high pressure liquid chromatography (UPLC) and tandem mass spectrometric (MS/MS) detection for the determination of GHB, beta-hydroxybutyrate (BHB), pregabalin, 1,4BD and GBL in whole blood and urine. Using the 96-well formate, the whole blood method is a simple high-throughput method suitable for screening of large sample amounts. With an easy sample preparation for urine including only dilution and filtration of the sample, the method is suitable for fast screening of urine samples. Both methods showed acceptable linearity, acceptable limits of detection, and limits of quantification. The within-day and between-day precisions of all analytes were lower than 10% RSD. The analytes were extracted from matrices with recoveries near 100%, and no major matrix effects were observed. Both methods have been used as routine screening analyses of whole blood and urine samples since January 2010. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Epoxidation and oxidation reactions using 1,4-butanediol ...

    Indian Academy of Sciences (India)

    Unknown

    droperoxide capacity of the polymeric reagent from. 2⋅86 meq/g to 3⋅31 meq/g when the reaction was performed under identical conditions. This may be attributed to the hydrophilic and flexible nature of the 1,4-BDDMA crosslinks imparting better hydro- phobic–hydrophilic balance for the macromolecular environment.

  10. Production of longer-chain alcohols from biomass - butanol, isopropanol and 2,3-butanediol

    NARCIS (Netherlands)

    Lopez Contreras, A.M.; Kuit, W.; Siemerink, M.A.J.; Kengen, S.W.M.; Springer, J.; Claassen, P.A.M.

    2010-01-01

    Bioethanol is one of the main biofuels capable of substituting petroleum usage in vehicles, and has had one of the largest impacts to date. The first generation of bioethanol production has had a worldwide impact, though it is restricted by energy intensive grain-to-bioethanol production technology,

  11. 76 FR 7703 - 1,4-Benzenedicarboxylic Acid, Dimethyl Ester, Polymer With 1,4-Butanediol, Adipic Acid, and...

    Science.gov (United States)

    2011-02-11

    ... controlled release agent) in honeybee hive miticide formulations under regulations for inert ingredients used... Federal Food, Drug, and Cosmetic Act (FFDCA), requesting establishment of an exemption from the... ingredient (component of controlled release agent) in miticide formulations applied to honeybee hives. That...

  12. Urinary excretion of 2-methyl-2,3-butanediol and 2,3-pentanediol in patients with disorders of propionate and methylmalonate metabolism

    NARCIS (Netherlands)

    Duran, M.; Ketting, D.; Bruinvis, L.; Dorland, L.; Wadman, S.K.; Bakkeren, J.A.J.M.

    1987-01-01

    Urine samples from patients with propionic acidemia and from a patient with methylmalonic acidemia contained unknown non-acidic metabolites by gas chromatography/mass spectrometry after ethyl acetate extraction. It could be demonstrated by mass spectrometric studies and by synthesis of reference

  13. Combining metabolic engineering and biocompatible chemistry for high-yield production of homo-diacetyl and homo-(S,S)-2,3-butanediol

    DEFF Research Database (Denmark)

    Liu, Jianming; Chan, Siu Hung Joshua; Brock-Nannestad, Theis

    2016-01-01

    Biocompatible chemistry is gaining increasing attention because of its potential within biotechnology for expanding the repertoire of biological transformations carried out by enzymes. Here we demonstrate how biocompatible chemistry can be used for synthesizing valuable compounds as well...... of 82%. The diacetyl and S-BDO production rates and yields obtained are the highest ever reported, demonstrating the promising combination of metabolic engineering and biocompatible chemistry as well as the great potential of L. lactis as a new production platform....

  14. High Production of 2,3-Butanediol (2,3-BD by Raoultella ornithinolytica B6 via Optimizing Fermentation Conditions and Overexpressing 2,3-BD Synthesis Genes.

    Directory of Open Access Journals (Sweden)

    Taeyeon Kim

    Full Text Available Biological production of 2,3-butandiol (2,3-BD has received great attention as an alternative to the petroleum-based 2,3-BD production. In this study, a high production of 2,3-BD in fed-batch fermentation was investigated with a newly isolated bacterium designated as Raoultella ornithinolytica B6. The isolate produced 2,3-BD as the main product using hexoses (glucose, galactose, and fructose, pentose (xylose and disaccharide (sucrose. The effects of temperature, pH-control schemes, and agitation speeds on 2,3-BD production were explored to optimize the fermentation conditions. Notably, cell growth and 2,3-BD production by R. ornithinolytica B6 were higher at 25°C than at 30°C. When three pH control schemes (no pH control, pH control at 7, and pH control at 5.5 after the pH was decreased to 5.5 during fermentation were tested, the best 2,3-BD titer and productivity along with reduced by-product formation were achieved with pH control at 5.5. Among different agitation speeds (300, 400, and 500 rpm, the optimum agitation speed was 400 rpm with 2,3-BD titer of 68.27 g/L, but acetic acid was accumulated up to 23.32 g/L. Further enhancement of the 2,3-BD titer (112.19 g/L, yield (0.38 g/g, and productivity (1.35 g/L/h as well as a significant reduction of acetic acid accumulation (9.71 g/L was achieved by the overexpression of homologous budABC genes, the 2,3-BD-synthesis genes involved in the conversion of pyruvate to 2,3-BD. This is the first report presenting a high 2,3-BD production by R.ornithinolytica which has attracted little attention with respect to 2,3-BD production, extending the microbial spectrum of 2,3-BD producers.

  15. Synthesis and characterization of poly(ester amide)s containing crystallizable amide segments

    NARCIS (Netherlands)

    Lips, P.A.M.; Broos, R.; van Heeringen, M.J.M.; Dijkstra, Pieter J.; Feijen, Jan

    2005-01-01

    High molecular weight segmented poly(ester amide)s were prepared by melt polycondensation of 1,4-butanediol, dimethyl adipate and a preformed bisamide-diol based on 1,4-diaminobutane and ε-caprolactone. By varying the ratio of the bisamide-diol and 1,4-butanediol, a series of polymers was obtained

  16. Cross-linked Polyethylenimine as Potential DNA Vector for Gene Delivery with High Efficiency and Low Cytotoxicity

    National Research Council Canada - National Science Library

    DONG, Wei; JIN, Guang-Hui; LI, Shu-Feng; SUN, Qi-Ming; MA, Ding-Yuan; HUA, Zi-Chun

    2006-01-01

    ... [1,4-butanediol diacrylate or ethyleneglycol dimethacrylate (EGDMA)] for 2-6 h. The efficiencies of the cross-linked PEI in in vitro transfection of plasmid DNA containing enhanced green fluorescent protein (EGFP...

  17. Genome-wide Escherichia coli stress response and improved tolerance towards industrially relevant chemicals

    DEFF Research Database (Denmark)

    Rau, Martin Holm; Calero Valdayo, Patricia; Lennen, Rebecca

    2016-01-01

    , hydroxy-γ-butyrolactone, 1,4-butanediol, furfural), organic acids (acetate, itaconic acid, levulinic acid, succinic acid), amino acids (serine, threonine) and membrane-intercalating chemicals (decanoic acid, geraniol). The transcriptional response towards these chemicals revealed large overlaps...

  18. Preparation and Properties of Novel Thermoplastic Vulcanizate Based on Bio-Based Polyester/Polylactic Acid, and Its Application in 3D Printing

    Directory of Open Access Journals (Sweden)

    Yu Gao

    2017-12-01

    Full Text Available Thermoplastic vulcanizate (TPV combines the high elasticity of elastomers and excellent processability of thermoplastics. Novel bio-based TPV based on poly (lactide (PLA and poly (1,4-butanediol/2,3-butanediol/succinate/itaconic acid (PBBSI were prepared in this research. PBBSI copolyesters were synthesized by melting polycondensation, and the molecular weights, chemical structures and compositions of the copolyesters were characterized by GPC, NMR and FTIR. Bio-based 2,3-butanediol was successfully incorporated to depress the crystallization behavior of the PBBSI copolyester. With an increase of 2,3-butanediol content, the PBBSI copolyester transformed from a rigid plastic to a soft elastomer. Furthermore, the obtained TPV has good elasticity and rheological properties, which means it can be applied as a 3D-printing material.

  19. Fully Biobased Unsaturated Aliphatic Polyesters from Renewable Resources : Enzymatic Synthesis, Characterization, and Properties

    NARCIS (Netherlands)

    Jiang, Yi; Alberda van Ekenstein, Gerhard; Woortman, Albert J. J.; Loos, Katja

    2014-01-01

    Fully biobased saturated and unsaturated aliphatic polyesters and oligoesters are successfully prepared by Candida antarctica lipase B (CALB)-catalyzed polycondensations of succinate, itaconate, and 1,4-butanediol. The effects of monomer substrates and polymerization methods on enzymatic

  20. Isolation and characterization of a new mucoid-free Klebsiella ...

    African Journals Online (AJOL)

    butanediol (2,3-BD) hyper-producer, hinders its application in large-scale fermentation because of pathogenicity, fermentation instability, and downstream difficulty. In this study, 14 K. pneumoniae strains were isolated from a waste water treatment ...

  1. The 3-hydroxy-2-butanone pathway is required for Pectobacterium carotovorum pathogenesis.

    Directory of Open Access Journals (Sweden)

    Maria del Pilar Marquez-Villavicencio

    Full Text Available Pectobacterium species are necrotrophic bacterial pathogens that cause soft rot diseases in potatoes and several other crops worldwide. Gene expression data identified Pectobacterium carotovorum subsp. carotovorum budB, which encodes the α-acetolactate synthase enzyme in the 2,3-butanediol pathway, as more highly expressed in potato tubers than potato stems. This pathway is of interest because volatiles produced by the 2,3-butanediol pathway have been shown to act as plant growth promoting molecules, insect attractants, and, in other bacterial species, affect virulence and fitness. Disruption of the 2,3-butanediol pathway reduced virulence of P. c. subsp. carotovorum WPP14 on potato tubers and impaired alkalinization of growth medium and potato tubers under anaerobic conditions. Alkalinization of the milieu via this pathway may aid in plant cell maceration since Pectobacterium pectate lyases are most active at alkaline pH.

  2. In situ extraction versus the use of an external column in fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Eiteman, M.A.; Gainer, J.L.

    1989-06-01

    Organic extraction of 2,3-butanediol produced by Klebsiella oxytoca fermentation was studied to determine if the use of an external column offered advantages over in situ extractive fermentation. Dodecanol was chosen from 24 tested solvents, 11 of which were non-toxic to K. oxytoca. Although growth occurred in all shakeflask experiments containing dodecanol, growth was never observed when dodecanol was used in an in situ arrangement in a fermentor. Using dodecanol in an external column, however, resulted in a cell yield of 0.10 g/g D-xylose, and a 2,3-butanediol yield of 0.32 g/g D-xylose, similar to results obtained in control (solventless) experiments. Although the partitioning of 2,3-butanediol in the organic phase was low, this study suggests that external columns, with recycling to the fermentor, can offer substantial advantages over in situ extraction.

  3. Effects of Solvent Diols on the Synthesis of ZnFe2O4 Particles and Their Use as Heterogeneous Photo-Fenton Catalysts

    Directory of Open Access Journals (Sweden)

    Chayene Gonçalves Anchieta

    2014-09-01

    Full Text Available A solvothermal method was used to prepare zinc ferrite spinel oxide (ZnFe2O4 using ethylene glycol and 1,4 butanediol as solvent diols, and the influence of diols on the physical properties of ZnFe2O4 particles was investigated. The produced particles were characterized by X-ray powder diffraction (XRD, atomic force microscopy (AFM, Fourier transform infrared spectroscopy (FTIR and nitrogen adsorption isotherms, and the catalytic activity for the organic pollutant decomposition by heterogeneous photo-Fenton reaction was investigated. Both solvents produced particles with cubic spinel structure. Microporous and mesoporous structures were obtained when ethylene glycol and 1,4 butanediol were used as diols, respectively. A higher pore volume and surface area, as well as a higher catalytic activity for the pollutant degradation were found when 1,4 butanediol was used as solvent.

  4. 77 FR 66149 - Significant New Use Rules on Certain Chemical Substances

    Science.gov (United States)

    2012-11-02

    ... alkane. CAS number: Not available. Basis for action: The PMNs state that the PMN substances will be used... (PCDFs) by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) study (EPA....10625. PMN Number P-12-373 Chemical name: 1,4-Butanediol, polymer with substituted alkane and...

  5. Diffusion coefficients at infinite dilution in water and in N-methylpyrrolidone

    NARCIS (Netherlands)

    Snijder, E.D.; te Riele, M.J.M.; Snijder, E.D.; van Swaaij, Willibrordus Petrus Maria

    1995-01-01

    The Taylor dispersion method has been used to determine diffusion coefficients of N-methylpyrrolidone, 2-methyl-2,4-pentanediol, glycerol, 1,3-butanediol, and 1,2,6-hexanetriol at infinite dilution in water and of water, glycerol, and 2-methyl-2,4-pentanediol at infinite dilution in

  6. Characterization and biocompatibility of epoxy-crosslinked dermal sheep collagens

    NARCIS (Netherlands)

    van Wachem, PB; Zeeman, R; Dijkstra, PJ; Feijen, J; Hendriks, M; Cahalan, PT; van Luyn, MJA

    1999-01-01

    Dermal sheep collagen (DSC), which was crosslinked with 1,4-butanediol diglycidyl ether (BD) by using four different conditions, was characterized and its biocompatibility was evaluated after subcutaneous implantation in rats. Crosslinking at pH 9.0 (BD90) or with successive epoxy and carbodiimide

  7. Inhibitory mechanism of 3-hydroxypropionaldehyde accumulation in ...

    African Journals Online (AJOL)

    Jane

    2011-07-13

    Jul 13, 2011 ... Glycerol kinase retained the highest residual activity of 74.68%, whereas fumarate reductase had the lowest value of 9.44%. What should be noted is that glycerol dehydrogenase, 1,3-PD oxidoreductase,. 2,3-butanediol oxidoreductase and ethanol dehydro- genase belong to the short-chain alcohol ...

  8. Networks 90: Polymer Networks Group Meeting (10th) and IUPAC international Symposium on Polymer Networks (10th) Held in Jerusalem on 20-25 May 1990. Programme and Abstracts

    Science.gov (United States)

    1990-05-25

    Antonio Rey and Walther Burcharda) a) Institute of Macromolecular Chemistry, University of Freiburg 7800 Freiburg, FRG b) Departimento di Quimica Fisica ...Ingenieria Quimica , 12 de octubre 1842, 8000 Bahia Blanca, Argentina. P-36 BRANCHING KINETICS OF EPOXY POLYMERIZATION OF 1,4-BUTANEDIOL DIGLYCIDYL ETHER

  9. Excess enthalpies of mixing, effect of temperature and composition on the density, and viscosity and thermodynamic properties of binary systems of {ammonium-based ionic liquid + alkanediol}.

    Science.gov (United States)

    Domańska, Urszula; Papis, Paulina; Szydłowski, Jerzy; Królikowska, Marta; Królikowski, Marek

    2014-11-06

    In the present work the excess enthalpies of butyltrimethylammonium bis(trifluoromethyl-sulfonyl)imide, [N1114][NTf2], with 1,2-propanediol, or 1,2-butanediol, or 2,3-butanediol have been measured at T = 298.15 K. Additionally, the density, ρ, and dynamic viscosity, η, for binary solutions containing ionic liquids (ILs) and alkanedioles, {butyltrimethylammonium bis(trifluoromethyl-sulfonyl)imide, [N1114][NTf2], + 1,2-propanediol, 1,2-butanediol, 2,3-butanediol} and {(2-hydroxyethyl)trimethylammonium bis(trifluoro-methylsulfonyl)imide, [N1112OH][NTf2], + 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol}, at wide temperature and composition ranges at ambient pressure have been investigated. From experimental values of the density, ρ, and dynamic viscosity, η, the excess molar volumes, V(E), and dynamic viscosity deviations, Δη, were calculated and correlated using the Redlich-Kister polynomial equation. The temperature dependence of density and viscosity for the tested binary systems was described by an empirical second-order polynomial and by the Vogel-Fucher-Tammann equation, respectively. The variation of density and viscosity as a function of composition has been described by the polynomial correlations. Comparison of the experimental results for the binary mixtures tested in this work allows us to determine the influence of alkanediol carbon chain length, the position of the hydroxyl group in the alcohol, and the influence of the structure of the cation of the ionic liquid on the presented properties.

  10. Comparison of different busulfan analogues for depletion of hematopoietic stem cells and promotion of donor-type chimerism in murine bone marrow transplant recipients

    NARCIS (Netherlands)

    G.R. Westerhof; R.E. Ploemacher (Robert); A. Boudewijn (Adrie); I. Blokland (Irene); J.H. Dillingh; A.T. McGown; J.A. Hadfield; M.J. Dawson; J.D. Down (Julian)

    2000-01-01

    textabstractBusulfan (1,4-butanediol dimethanesulfonate, BU) is relatively unique among other standard chemotherapy compounds in its ability to deplete noncycling primitive stem cells in the host and consequently to allow for high levels of long-term, donor-type

  11. Determination of properties of fluids for solar-cooling applications. Literature survey

    Energy Technology Data Exchange (ETDEWEB)

    Podoll, R.T.

    1981-02-01

    A detailed literature search of the available thermodynamic data of proposed refrigerant/absorbent pairs and measurement of those data that are unmeasured or unreliable are reported. The data to be obtained for the pure fluids included: the critical temperature, pressure and volume; the vapor pressure curve; the latent heat of vaporization at the normal boiling point; the freezing point; the specific heat of the liquid and vapor; and the specific volumes of the saturated liquids and vapors. For the fluid mixtures, the data included the dew point and bubble point at four specified pressures plus the heats of mixing and specific heat at several solution compositions. Pure fluids surveyed included: ammonia, methylamine, ethylamine, chlorodifluoromethane (R-22), fluorodichloromethane (R-21), ethylene glycol, 1,4-Butanediol, diethylene glycol dimethyl ether (DGDE), N,N-dimethylacetamide (DMA), N,N-dimethylhexanamide (DMH), N,N-dimethyldecanamide (DMD). Binary fluid mixtures surveyed included: ammonia/ethylene glycol; ammonia/1,4-butanediol; methylamine/ethylene glycol; methylamine/1,4-butanediol; ethylamine/ethylene glycol; ethylamine/1,4-butanediol; and R-22/ DGDE. (LEW)

  12. Risk Factors for Neonatal Sepsis and Method for Reduction of Blood ...

    African Journals Online (AJOL)

    2015-03-24

    Mar 24, 2015 ... Neonatal Sepsis 21 http://dx.doi.org/10.4314/mmj.v27i1.6. In group 1 no standarized technique for blood culture collection was used (nurses used nonsterile gloves, no well-defined sterile field, 70% isopropyl alcohol and 0.1% butanediol for skin antisepsis). Checklists for the procedure were not provided.

  13. Co- and Terpolyesters based on isosorbide and succinic acid for coating applications : synthesis and characterization

    NARCIS (Netherlands)

    Noordover, B.A.J.; Staalduinen, van V.G.; Duchateau, R.; Koning, C.E.; Benthem, van R.A.T.M.; Mak, M.; Heise, A.; Frissen, A.E.; Haveren, van J.

    2006-01-01

    Co- and terpolyesters based on succinic acid and isosorbide in combination with other renewable monomers such as 2,3-butanediol, 1,3-propanediol, and citric acid were synthesized and characterized. Linear polyesters were obtained via melt polycondensation of nonactivated dicarboxylic acids with OH

  14. Environmentally degradable aliphatic poly(ester-amide)s based on short, symmetrical and uniform bisamide-diol blocks, 1. Synthesis and interchange reaction

    NARCIS (Netherlands)

    Stapert, Hendrik R.; Stapert, H.R.; Bouwens, Anna-Malin; Dijkstra, Pieter J.; Feijen, Jan

    1999-01-01

    Aliphatic poly(ester-amide)s were prepared by polycondensation of N,N-1,4 butanediylbis(6-hydroxyhexanamide), dimethyl adipate, and 1,4-butanediol, using Ti(OBu)4 as a catalyst. For polymers with a bisamide monomer content below 25 mol-%, Mw between 20 000 and 50 000 were obtained after 10-12 h

  15. Incorporation of different crystallizable amide blocks in segmented poly(ester amide)s

    NARCIS (Netherlands)

    Lips, P.A.M.; Broos, R.; van Heeringen, M.J.M.; Dijkstra, Pieter J.; Feijen, Jan

    2005-01-01

    High molecular weight segmented poly(ester amide)s were prepared by melt polycondensation of dimethyl adipate, 1,4-butanediol and a symmetrical bisamide-diol based on ε-caprolactone and 1,2-diaminoethane or 1,4-diaminobutane. FT-IR and WAXD analysis revealed that segmented poly(ester amide)s based

  16. Electrospun Polyurethane Fibers for Absorption of Volatile Organic Compounds from Air

    NARCIS (Netherlands)

    Scholten, E.; Bromberg, L.; Rutledge, G.C.; Hatton, T.A.

    2011-01-01

    Electrospun polyurethane fibers for removal of volatile organic compounds (VOC) from air with rapid VOC absorption and desorption have been developed. Polyurethanes based on 4,4-methylenebis(phenylisocyanate) (MDI) and aliphatic isophorone diisocyanate as the hard segments and butanediol and

  17. Synthesis and characterization of bio-based polyurethane from ...

    Indian Academy of Sciences (India)

    Benzoylated tannin prepared by benzoylation of cashewnut husk tannin, was treated with hexame-thylenediisocyanate in the presence of 1,4-butanediol as an extender to prepare thermosetting polyurethane. The sample was characterized using FT–IR and 13C NMR spectra. Thermal, morphological, physico-chemical and ...

  18. 21 CFR 74.3045 - [Phthalocyaninato(2-)] copper.

    Science.gov (United States)

    2010-04-01

    ... the structure shown in Colour Index No. 74160. (b) Specifications. The color additive.... Total color, not less than 98.5 percent. (c) Uses and restrictions. (1) The color additive... designation for the suture fabricated from 1,4-benzenedicarboxylic acid, polymer with 1,4-butanediol and alpha...

  19. Interesting Starter Culture Strains for Controlled Cocoa Bean Fermentation Revealed by Simulated Cocoa Pulp Fermentations of Cocoa-Specific Lactic Acid Bacteria ▿

    Science.gov (United States)

    Lefeber, Timothy; Janssens, Maarten; Moens, Frédéric; Gobert, William; De Vuyst, Luc

    2011-01-01

    Among various lactic acid bacterial strains tested, cocoa-specific strains of Lactobacillus fermentum were best adapted to the cocoa pulp ecosystem. They fermented glucose to lactic acid and acetic acid, reduced fructose to mannitol, and converted citric acid into lactic acid and 2,3-butanediol. PMID:21803901

  20. Pengaruh Penambahan 1,4-Butanadiol dan Polietilen Glikol (PEG 1000 terhadap Kemudahan Biodegradasi Bioplastik dari Biji Nangka (Artocarpus heterophyllus

    Directory of Open Access Journals (Sweden)

    Argo Khoirul Anas

    2016-10-01

    Full Text Available The influences of plasticizer on the biodegradability of bioplastic film synthesized from starch obtained from jackfruit seeds with a help of Acetobacter xylinum were investigated. In this study, 1,4-butanediol and polyethylene glycol (PEG 1000 were used as plasticizer. The biodegradation behavior of the resulted bioplastic films was characterized by calculating changes in their mass loss and rate of mass loss. The Fourier Transform Infrared (FTIR spectroscopy was also conducted to analyze theirfunctional group. The results shows that all the bioplastic films were well biodegradated, where PEG 1000 with concentration of 0,5% and 1,0% can successfully improve the biodegradability of bioplasticfilm. Meanwhile, the used of 1,4-butanediol with concentration of 0,5% and 1,0% can increase and decrease the biodegradability of sample, respectively.

  1. 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.

  2. Biotechnology for producing fuels and chemicals from biomass. Volume 2: Fermentation chemicals from biomass

    Science.gov (United States)

    Villet, R.

    1981-02-01

    The technological and economic feasibility of producing chemicals by fermentation is discussed: acetone; butanol; acetic acid; citric acid; 2,3-butanediol, and propionic acid. Improved cost of fermentative production will hinge on improving yields and using cellulosic feedstocks. The market for acetic acid is likely to grow 5 percent to 7 percent/yr. A potential process for production is the fermentation of hydrolyzed cellulosic material to ethanol followed by chemical conversion to acetic acid. The feedstock cost is 15 to 20 percent of the overall cost of production. The anticipated 5 percent growth in demand for citric acid could be enhanced by using it to displace phosphates in detergent manufacture. A number of useful chemicals can be derived from 2,3-butanediol, which has not been produced commercially on a large scale. The commercial fermentative production of propionic acid has not yet been developed.

  3. 40 CFR 180.450 - Beta-(4-Chlorophenoxy)-alpha-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol; tolerances for...

    Science.gov (United States)

    2010-07-01

    ...-dimethylethyl)-1H-1,2,4-triazole-1-ethanol; tolerances for residues. 180.450 Section 180.450 Protection of...-dimethylethyl)-1H-1,2,4-triazole-1-ethanol; tolerances for residues. (a) General. Tolerances are established for...-ethanol (triadimenol) and its butanediol metabolite, 4-(4-chlorophenoxy)-2,2-dimethyl-4-(1H-1,2,4-triazol...

  4. Methods for sanitary surveillance of livestock production. VII. Enzymoimmunoassay of streptomycin

    OpenAIRE

    M.A. Burkin; I.A. Gal’vidis; G.P. KONONENKO

    2012-01-01

    The polyclonal rabbit antibodies against streptomycin conjugated with bovine serum albumin in reaction with diglycidyl ether of 1,4-butanediol presents high specificity to streptomycin and its similar structural analog — dihydrostreptomycin. In the conditions of indirect competitive enzymoimmunoassay with immobilized antigens, heterologous to immunogene on protein carrier and methods of synthesis, the limit of streptomycin detection is 0.1 ng/ml. The authors consider the use of developed immu...

  5. Swelling of Superabsorbent Acrylamide/Sodium Acrylate Hydrogels Prepared Using Multifunctional Crosslinkers

    OpenAIRE

    KARADAĞ, Erdener

    2014-01-01

    Superwaterabsorbent acrylamide-sodium acrylate hydrogels were Prepared by free radical polymerization in aqueous solutions of acrylamide and of acrylamide with sodium acrylate as comonomer. For each copolymerization, nine different compositions were used and in all systems a concentration of a multifunctional crosslinker such as trimethylolpropane triacrylate, ethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate and N,N'-methylenebisacrylamide was employed. As a re...

  6. Ariensin, a new lignan from Bursera ariensis.

    Science.gov (United States)

    Hernández, J D; Román, L U; Espiñeira, J; Joseph-Nathan, P

    1983-04-01

    From acetone extracts of the exudate of the tree Bursera ariensis, a new bilignan, named ariensin, has been isolated and characterized as (2R,3R)-bis-2.3-(3.4-methylenedioxybenzyl-)-1.4-butanediol diacetate. The structure has been determined from UV, IR, (1)H-NMR and (13)C-NMR data of the natural product, the dibromo derivative and the hydrolysis product. The optical rotation of the latter allowed the determination of the absolute configuration.

  7. Research in Energetic Compounds

    Science.gov (United States)

    1983-01-01

    Solvent % Yield hol - treatment polymer wt Dried/ mol sieve 50-60 2400+ None, 0.2% water 55 240U+ 1 moldmanomer added 16 2000+ 761 800+ * 0.1 Mole 3... water content or ’he use of 1,4-butanediol as a cocatalyst. Increasing the monomer concentration from 20% to. 50%, however. aave 80--0% yields of...21 Peracid Oxidation of 2--Aminoadamantane . 22 Reaction of 4-Bromo-2,2-dinitroadamantane with Sodium Azide

  8. Pengaruh Penambahan 1,4-Butanadiol dan Polietilen Glikol (PEG) 1000 terhadap Kemudahan Biodegradasi Bioplastik dari Biji Nangka (Artocarpus Heterophyllus)

    OpenAIRE

    Anas, Argo Khoirul; Ariefta, Nanang Rudianto; Nurfiana, Yuni; Rohaeti, Eli

    2016-01-01

    The influences of plasticizer on the biodegradability of bioplastic film synthesized from starch obtained from jackfruit seeds with a help of Acetobacter xylinum were investigated. In this study, 1,4-butanediol and polyethylene glycol (PEG) 1000 were used as plasticizer. The biodegradation behavior of the resulted bioplastic films was characterized by calculating changes in their mass loss and rate of mass loss. The Fourier Transform Infrared (FTIR) spectroscopy was also conducted to analyze ...

  9. An energetic model for oxygen-limited metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Beronio, P.B. Jr. (Amoco Oil Co., Naperville, IL (United States). Amoco Research Center); Tsao, G.T. (Purdue Univ., West Lafayette, IN (United States). Lab. of Renewable Resources Engineering)

    1993-12-01

    Microbial production of 2,3-butanediol by Klebsiella oxytoca occurs under conditions of an oxygen limitation. The extent to which substrate is oxidized to 2,3-butanediol and its coproducts, (acetic acid, acetoin, and ethanol) and the relative flow rates of substrate to energetic and biosynthetic pathways are controlled by the degree of oxygen limitation. Two energetic relationships which describe the response to an oxygen limitation have been derived. The first relationship describes the coupling between growth and energy production observed under oxygen-limited conditions. This allows calculation of energetic parameters and modeling of the cell mass and substrate profiles in terms of the degree of oxygen limitation only. The second relationship describes the average degree of oxidation and the rate of the end-product flow. The model has been tested with both batch and continuous culture. During these kinetic studies, two phases of growth have been observed: energy-coupled growth, which was described above; and, energy-uncoupled growth, which arises when the degree of oxygen limitation reaches a critical value. Optimal culture performance with respect to 2,3-butanediol productivity occurs during energy-coupled growth.

  10. Biofuel and chemical production by recombinant microorganisms via fermentation of proteinaceous biomass

    Science.gov (United States)

    Liao, James C.; Cho, Kwang Myung; Yan, Yajun; Huo, Yixin

    2016-03-15

    Provided herein are metabolically modified microorganisms characterized by having an increased keto-acid flux when compared with the wild-type organism and comprising at least one polynucleotide encoding an enzyme that when expressed results in the production of a greater quantity of a chemical product when compared with the wild-type organism. The recombinant microorganisms are useful for producing a large number of chemical compositions from various nitrogen containing biomass compositions and other carbon sources. More specifically, provided herein are methods of producing alcohols, acetaldehyde, acetate, isobutyraldehyde, isobutyric acid, n-butyraldehyde, n-butyric acid, 2-methyl-1-butyraldehyde, 2-methyl-1-butyric acid, 3-methyl-1-butyraldehyde, 3-methyl-1-butyric acid, ammonia, ammonium, amino acids, 2,3-butanediol, 1,4-butanediol, 2-methyl-1,4-butanediol, 2-methyl-1,4-butanediamine, isobutene, itaconate, acetoin, acetone, isobutene, 1,5-diaminopentane, L-lactic acid, D-lactic acid, shikimic acid, mevalonate, polyhydroxybutyrate (PHB), isoprenoids, fatty acids, homoalanine, 4-aminobutyric acid (GABA), succinic acid, malic acid, citric acid, adipic acid, p-hydroxy-cinnamic acid, tetrahydrofuran, 3-methyl-tetrahydrofuran, gamma-butyrolactone, pyrrolidinone, n-methylpyrrolidone, aspartic acid, lysine, cadeverine, 2-ketoadipic acid, and/or S-adenosyl-methionine (SAM) from a suitable nitrogen rich biomass.

  11. Pareto Optimal Design for Synthetic Biology.

    Science.gov (United States)

    Patanè, Andrea; Santoro, Andrea; Costanza, Jole; Carapezza, Giovanni; Nicosia, Giuseppe

    2015-08-01

    Recent advances in synthetic biology call for robust, flexible and efficient in silico optimization methodologies. We present a Pareto design approach for the bi-level optimization problem associated to the overproduction of specific metabolites in Escherichia coli. Our method efficiently explores the high dimensional genetic manipulation space, finding a number of trade-offs between synthetic and biological objectives, hence furnishing a deeper biological insight to the addressed problem and important results for industrial purposes. We demonstrate the computational capabilities of our Pareto-oriented approach comparing it with state-of-the-art heuristics in the overproduction problems of i) 1,4-butanediol, ii) myristoyl-CoA, i ii) malonyl-CoA , iv) acetate and v) succinate. We show that our algorithms are able to gracefully adapt and scale to more complex models and more biologically-relevant simulations of the genetic manipulations allowed. The Results obtained for 1,4-butanediol overproduction significantly outperform results previously obtained, in terms of 1,4-butanediol to biomass formation ratio and knock-out costs. In particular overproduction percentage is of +662.7%, from 1.425 mmolh⁻¹gDW⁻¹ (wild type) to 10.869 mmolh⁻¹gDW⁻¹, with a knockout cost of 6. Whereas, Pareto-optimal designs we have found in fatty acid optimizations strictly dominate the ones obtained by the other methodologies, e.g., biomass and myristoyl-CoA exportation improvement of +21.43% (0.17 h⁻¹) and +5.19% (1.62 mmolh⁻¹gDW⁻¹), respectively. Furthermore CPU time required by our heuristic approach is more than halved. Finally we implement pathway oriented sensitivity analysis, epsilon-dominance analysis and robustness analysis to enhance our biological understanding of the problem and to improve the optimization algorithm capabilities.

  12. Genome sequence of the plant growth promoting endophytic bacterium Enterobacter sp. 638.

    Directory of Open Access Journals (Sweden)

    Safiyh Taghavi

    2010-05-01

    Full Text Available Enterobacter sp. 638 is an endophytic plant growth promoting gamma-proteobacterium that was isolated from the stem of poplar (Populus trichocarpaxdeltoides cv. H11-11, a potentially important biofuel feed stock plant. The Enterobacter sp. 638 genome sequence reveals the presence of a 4,518,712 bp chromosome and a 157,749 bp plasmid (pENT638-1. Genome annotation and comparative genomics allowed the identification of an extended set of genes specific to the plant niche adaptation of this bacterium. This includes genes that code for putative proteins involved in survival in the rhizosphere (to cope with oxidative stress or uptake of nutrients released by plant roots, root adhesion (pili, adhesion, hemagglutinin, cellulose biosynthesis, colonization/establishment inside the plant (chemiotaxis, flagella, cellobiose phosphorylase, plant protection against fungal and bacterial infections (siderophore production and synthesis of the antimicrobial compounds 4-hydroxybenzoate and 2-phenylethanol, and improved poplar growth and development through the production of the phytohormones indole acetic acid, acetoin, and 2,3-butanediol. Metabolite analysis confirmed by quantitative RT-PCR showed that, the production of acetoin and 2,3-butanediol is induced by the presence of sucrose in the growth medium. Interestingly, both the genetic determinants required for sucrose metabolism and the synthesis of acetoin and 2,3-butanediol are clustered on a genomic island. These findings point to a close interaction between Enterobacter sp. 638 and its poplar host, where the availability of sucrose, a major plant sugar, affects the synthesis of plant growth promoting phytohormones by the endophytic bacterium. The availability of the genome sequence, combined with metabolome and transcriptome analysis, will provide a better understanding of the synergistic interactions between poplar and its growth promoting endophyte Enterobacter sp. 638. This information can be further

  13. Investigation on the Influence of Chain Extenders on the Performance of One-Component Moisture-Curable Polyurethane Adhesives

    Directory of Open Access Journals (Sweden)

    Chen Tan

    2017-05-01

    Full Text Available In this work, a number of chain extended moisture-curable urethane prepolymers were synthesized in order to develop isocyanate terminated urethane prepolymer formulations that would simultaneously display both high adhesive strength and low viscosity. Proton nuclear magnetic resonance spectroscopy (1H-NMR, size exclusion chromatography (SEC, differential scanning calorimetry (DSC, and Brookfield viscometry were utilized for characterizing the prepared urethane prepolymers. In addition, the adhesion strength of the cured prepolymers was determined by tensile shear strength test according to the DIN EN (Deutsches Institut für Normung, the German Institute for Standardization 1465 standard. Especially, the role of different types of linear (butanediol, pentanediol and branched chain extenders (dipropyleneglycol (di-PPG, tripropyleneglycol (tri-PPG and the influence of their dosage on the degree of microphase separation between hard segments (HS and soft segments (SS in urethane prepolymers were studied. Furthermore, the benefits of utilizing either a one-step versus a two-step polymerization process were investigated. The results revealed that the extent of phase separation of different urethane prepolymers was dependent on the extent of hydrogen bonding interactions which was extensively studied by attenuated total reflectance infrared spectroscopy (ATR-FTIR. The incorporation of branched chain extenders (di-PPG and tri-PPG did not result in notable phase separation between hard segments and soft segments, while linear chain extenders (pentanediol and butanediol readily promoted phase separation. The degree of phase separation was particularly pronounced for butanediol, and when the linear chain extender ratio was higher than or equal to 0.74. Compared with a two-stage process, one-stage process produced more randomly distributed polymer chains with highly dispersed hard segments. Thus, urethane prepolymers exhibiting strong adhesive strength

  14. Improving GHB withdrawal with baclofen: study protocol for a feasibility study for a randomised controlled trial

    OpenAIRE

    Lingford-Hughes, AR; Y; Patel; Bowden-Jones, O; Crawford, M.; Dargan, P; Gordon, F.; Parrott, S.; Weaver, T.; Wood, D.

    2016-01-01

    Background GHB (gamma-hydroxybutyrate) and its pro-drugs GBL (gamma-butyrolactone) and 1,4-butanediol (1,4-BD) are central nervous system depressants whose street names include ?G? and ?liquid ecstasy?. They are used recreationally predominately for their stimulant and pro-sexual effects or for sedation to help with sleep and/or to ?come down? after using stimulant recreational drugs. Although overall population prevalence is low (0.1?%), in some groups such as men who have sex with men, GHB/...

  15. DEVELOPMENT OF BIOSURFACTANT-MEDIATED OIL RECOVERY IN MODEL POROUS SYSTEMS AND COMPUTER SIMULATIONS OF BIOSURFACTANT-MEDIATED OIL RECOVERY

    Energy Technology Data Exchange (ETDEWEB)

    M.J. McInerney; S.K. Maudgalya; R. Knapp; M. Folmsbee

    2004-05-31

    Current technology recovers only one-third to one-half of the oil that is originally present in an oil reservoir. Entrapment of petroleum hydrocarbons by capillary forces is a major factor that limits oil recovery (1, 3, 4). Hydrocarbon displacement can occur if interfacial tension (IFT) between the hydrocarbon and aqueous phases is reduced by several orders of magnitude. Microbially-produced biosurfactants may be an economical method to recover residual hydrocarbons since they are effective at low concentrations. Previously, we showed that substantial mobilization of residual hydrocarbon from a model porous system occurs at biosurfactant concentrations made naturally by B. mojavensis strain JF-1 if a polymer and 2,3-butanediol were present (2). In this report, we include data on oil recovery from Berea sandstone experiments along with our previous data from sand pack columns in order to relate biosurfactant concentration to the fraction of oil recovered. We also investigate the effect that the JF-2 biosurfactant has on interfacial tension (IFT). The presence of a co-surfactant, 2,3-butanediol, was shown to improve oil recoveries possibly by changing the optimal salinity concentration of the formulation. The JF-2 biosurfactant lowered IFT by nearly 2 orders of magnitude compared to typical values of 28-29 mN/m. Increasing the salinity increased the IFT with or without 2,3-butanediol present. The lowest interfacial tension observed was 0.1 mN/m. Tertiary oil recovery experiments showed that biosurfactant solutions with concentrations ranging from 10 to 60 mg/l in the presence of 0.1 mM 2,3-butanediol and 1 g/l of partially hydrolyzed polyacrylamide (PHPA) recovered 10-40% of the residual oil present in Berea sandstone cores. When PHPA was used alone, about 10% of the residual oil was recovered. Thus, about 10% of the residual oil recovered in these experiments was due to the increase in viscosity of the displacing fluid. Little or no oil was recovered at

  16. Mesoporous tertiary oxides via a novel amphiphilic approach

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Natasha; Hall, Simon R., E-mail: simon.hall@bristol.ac.uk, E-mail: Annela.Seddon@bristol.ac.uk [Bristol Centre for Functional Nanomaterials, Centre for Nanoscience and Quantum Information, Tyndall Avenue, Bristol BS8 1FD, United Kingdom and Complex Functional Materials Group, School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom); Seddon, Annela M., E-mail: simon.hall@bristol.ac.uk, E-mail: Annela.Seddon@bristol.ac.uk; Hallett, James E. [H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Kockelmann, Winfried [STFC Rutherford Appleton Laboratory, Chilton OX11 0QX (United Kingdom); Ting, Valeska P. [Department of Chemical Engineering, University of Bath, Bath BA2 7AY (United Kingdom); Sadasivan, Sajanikumari; Tooze, Robert P. [Sasol Technology (UK) Ltd, Purdie Building, North Haugh, St Andrews, Fife KY16 9ST (United Kingdom)

    2016-01-01

    We report a facile biomimetic sol-gel synthesis using the sponge phase formed by the lipid monoolein as a structure-directing template, resulting in high phase purity, mesoporous dysprosium- and gadolinium titanates. The stability of monoolein in a 1,4-butanediol and water mixture complements the use of a simple sol-gel metal oxide synthesis route. By judicious control of the lipid/solvent concentration, the sponge phase of monoolein can be directly realised in the pyrochlore material, leading to a porous metal oxide network with an average pore diameter of 10 nm.

  17. Mesoporous tertiary oxides via a novel amphiphilic approach

    Directory of Open Access Journals (Sweden)

    Natasha Bennett

    2016-01-01

    Full Text Available We report a facile biomimetic sol-gel synthesis using the sponge phase formed by the lipid monoolein as a structure-directing template, resulting in high phase purity, mesoporous dysprosium- and gadolinium titanates. The stability of monoolein in a 1,4-butanediol and water mixture complements the use of a simple sol-gel metal oxide synthesis route. By judicious control of the lipid/solvent concentration, the sponge phase of monoolein can be directly realised in the pyrochlore material, leading to a porous metal oxide network with an average pore diameter of 10 nm.

  18. Synthesis and characterization of isophorone diisocyanate based polyurethanes

    Science.gov (United States)

    Mirčeva, A.; Malavašič, T.; Osredkar, U.

    1990-03-01

    Polyurethane ionomers based on polycaprolactone glycol or polyoxytetramethylene glycol with isophorone diisocyanate and chain extenders 1,4-butanediol, 2,2'(dihydroxymethyl) propionic acid and in some cases water, were synthesized in solution. Stable aqueous dispersions from the ionomers were obtained when the concentration of ionic groups was at least 30 mmol per 100 g of polyurethane. Higher concentration of hard segments in the structure produced elastic and transparent films. Hard-soft segment interactions in a series of model compounds were estimated by Fourier transform infrared spectroscopy. Thermal properties of the films were determined by differential scanning calorimetry and by FTIR as well.

  19. Solvent Based Self Healing Epoxy Materials

    Science.gov (United States)

    2008-01-01

    from Zeeland Chemicals, and 1,4-butanediol and cyclohexanone were purchased from Sigma-Aldrich and used as received. EPON ® 828 , EPON ® 862, EPICURE...s-1. The epoxies tested include: 100:12 parts per hundred (pph) mixture of EPON 828 :DETA, 100:50 pph mixture of EPON 862:EPICURE 3274, and 100:16...pph mixture of EPON 828 :TEPA. The resins underwent the cure cycle of 24 h at room temperature, and a subsequent 24 h at 35 ˚C. EPON 828 :DETA was

  20. Comparison between Properties of Polyurethane Nanocomposites Prepared by Two Different Methods

    Directory of Open Access Journals (Sweden)

    M. Barmar

    2008-12-01

    Full Text Available In this work, a thermoplastic polyurethane elastomer (TPUE model based on polytetramethylene glycol, toluene diisocyanate and 1,4-butanediol was selected and synthesized. According to this model two types of polyurethane nanocomposites were prepared by in situ polymerization and melt intercalation procedures. The organo-modified nanoclay was used in nanocomposites samples in 0.4 weight percent level. The prepared nanocomposites were studied by WAXD, tensile and thermal analysis. Thermal properties of the nanocomposites were higher than those of pure polyurethane elastomers. Nanocomposites prepared via melt intercalation method showed a lower tensile strength and hardness than those prepared through in situ polymerization method..

  1. Simultaneous determination of gamma-Hydroxybutyrate (GHB) and its analogues (GBL, 1.4-BD, GVL) in whole blood and urine by liquid chromatography coupled to tandem mass spectrometry

    DEFF Research Database (Denmark)

    Johansen, Sys Stybe; Windberg, Charlotte Norup

    2011-01-01

    . The sample preparation of whole blood involved protein precipitation by acidic methanol. Urine samples were diluted and evaluated in relation to a control at the cutoff concentration. Hexadeutero GHB (GHB-d(6)) was used as the internal standard. Separation was achieved by reversed-phase chromatography......A simple liquid chromatography-tandem mass spectrometry (LC-MS-MS) method has been developed and validated for simultaneous identification and quantification of ¿-hydroxybutyrate (GHB), ¿-butyrolactone (GBL), 1.4-butanediol (1.4-BD), and ¿-valerolactone (GVL) in whole blood from forensic cases...

  2. Evaluation of level of impregnation monomers in hydrotalcite; Avaliacao do grau de impregnacao de monomeros em hidrotalcita

    Energy Technology Data Exchange (ETDEWEB)

    Carmo, Danieli M. do, E-mail: danielimcarmo@hotmail.com [Instituto de Macromoleculas Professora Eloisa Mano - IMA, Universidade Federal do Rio de Janeiro - UFRJ, RJ (Brazil); Machado, Jacson S.C.; Oliveira, Marcelo F.L.; Oliveira, Marcia G. [Instituto Nacional de Tecnologia - INT, Rio de Janeiro, RJ (Brazil); Soares, Bluma G. [Instituto de Macromoleculas Professora Eloisa Mano - IMA, Universidade Federal do Rio de Janeiro - UFRJ, RJ (Brazil)

    2011-07-01

    To evaluate the impregnation degree of 1,6-hexamethylene diisocyanate and 1,4-butanediol monomers in hydrotalcite clays it was prepared dispersions with mixing ratio 1:100 (clay/monomer), using the Ultraturrax and Ultrasound. Subsequently the samples were characterized by Fourier Transform Infrared Spectroscopy and X-ray Diffraction. Swelling tests and Tyndall effect were used to illustrate the different dispersions. The results indicated a strong interaction between the hydrotalcite with 1,6-hexamethylene diisocyanate, favoring the formation of intercalated structures. (author)

  3. Preparation and Characterization of Fluorinated Hydrophobic UV-Crosslinkable Thiol-Ene Polyurethane Coatings

    Directory of Open Access Journals (Sweden)

    Wenjing Xia

    2017-08-01

    Full Text Available The polyurethane prepolymer terminated with a double bond was synthesized using isophorone diisocyanate (IPDI, hydroxyl terminated polybutadiene (HTPB, 1,4-butanediol (BDO, and 2-hydroxyethyl acrylate (HEA. Then, a series of innovative UV-curable polyurethane coatings were prepared by blending ene-terminated polyurethane, fluoroacrylate monomer, and multifunctional thiol crosslinker upon UV exposure. The incorporation of fluoroacrylate monomer and multifunctional thiols into polyurethane coatings significantly enhanced the hydrophobic property, mechanical property, pencil hardness, and glossiness of the polyurethane coatings. This method of preparing UV crosslinkable, hydrophobic polyurethane coatings based on thiol-ene chemistry exhibited numerous advantages over other UV photocuring systems.

  4. The oxidation of chiral alcohols catalyzed by catalase in organic solvents

    Energy Technology Data Exchange (ETDEWEB)

    Magner, E.; Klibanov, A.M. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Chemistry

    1995-04-20

    The catalytic properties of bovine liver catalase have been investigated in organic solvents. In tetrahydrofuran, dioxane, and acetone (all containing 1% to 3% of water), the enzyme breaks down tert-butyl hydroperoxide several fold faster than in pure water. Furthermore, the rate of catalase-catalyzed production of tert-butanol from tert-butyl hydroperoxide increases more than 400-fold upon transition from aqueous buffer to ethanol as the reaction medium. The mechanistic rationale for this striking effect is that in aqueous buffer the rate-limiting step of the enzymatic process involves the reduction of catalase`s compound 1 by tert-butyl hydroperoxide. In ethanol, an additional step in the reaction scheme becomes available in which ethanol, greatly outcompeting the hydroperoxide, is oxidized by compound 1 regenerating the free enzyme. In solvents, such as acetonitrile or tetrahydrofuran, which themselves are not oxidizable by compound 1, catalase catalyzes the oxidation of numerous primary and secondary alcohols with tert-butyl hydroperoxide to the corresponding aldehydes or ketones. The enzymatic oxidation of some chiral alcohols (2,3-butanediol, citronellol, and menthol) under these conditions occurs enantioselectively. Examination of the enantioselectivity for the oxidation of 2,3-butanediol in a series of organic solvents reveals a considerable solvent dependence.

  5. Using slaughterhouse waste in a biochemical-based biorefinery - results from pilot scale tests.

    Science.gov (United States)

    Schwede, Sebastian; Thorin, Eva; Lindmark, Johan; Klintenberg, Patrik; Jääskeläinen, Ari; Suhonen, Anssi; Laatikainen, Reino; Hakalehto, Elias

    2017-05-01

    A novel biorefinery concept was piloted using protein-rich slaughterhouse waste, chicken manure and straw as feedstocks. The basic idea was to provide a proof of concept for the production of platform chemicals and biofuels from organic waste materials at non-septic conditions. The desired biochemical routes were 2,3-butanediol and acetone-butanol fermentation. The results showed that hydrolysis resulted only in low amounts of easily degradable carbohydrates. However, amino acids released from the protein-rich slaughterhouse waste were utilized and fermented by the bacteria in the process. Product formation was directed towards acidogenic compounds rather than solventogenic products due to increasing pH-value affected by ammonia release during amino acid fermentation. Hence, the process was not effective for 2,3-butanediol production, whereas butyrate, propionate, γ-aminobutyrate and valerate were predominantly produced. This offered fast means for converting tedious protein-rich waste mixtures into utilizable chemical goods. Furthermore, the residual liquid from the bioreactor showed significantly higher biogas production potential than the corresponding substrates. The combination of the biorefinery approach to produce chemicals and biofuels with anaerobic digestion of the residues to recover energy in form of methane and nutrients that can be utilized for animal feed production could be a feasible concept for organic waste utilization.

  6. Dibasic Ammonium Phosphate Application Enhances Aromatic Compound Concentration in Bog Bilberry Syrup Wine.

    Science.gov (United States)

    Wang, Shao-Yang; Li, Yi-Qing; Li, Teng; Yang, Hang-Yu; Ren, Jie; Zhang, Bo-Lin; Zhu, Bao-Qing

    2016-12-29

    A nitrogen deficiency always causes bog bilberry syrup wine to have a poor sensory feature. This study investigated the effect of nitrogen source addition on volatile compounds during bog bilberry syrup wine fermentation. The syrup was supplemented with 60, 90, 120 or 150 mg/L dibasic ammonium phosphate (DAP) before fermentation. Results showed that an increase of DAP amounts accelerated fermentation rate, increased alcohol content, and decreased sugar level. Total phenol and total flavonoid content were also enhanced with the increase of DAP amounts. A total of 91 volatile compounds were detected in the wine and their concentrations were significantly enhanced with the increase of DAP. Ethyl acetate, isoamyl acetate, phenethyl acetate, ethyl butanoate, ethyl hexanoate, ethyl octanoate, ethyl decanoate, isobutanol, isoamyl alcohol, levo-2,3-butanediol, 2-phenylethanol, meso-2,3-butanediol, isobutyric acid, hexanoic acid, and octanoic acid exhibited a significant increase of their odor activity value (OAV) with the increase of DAP amounts. Bog bilberry syrup wine possessed fruity, fatty, and caramel flavors as its major aroma, whereas a balsamic note was the least present. The increase of DAP amounts significantly improved the global aroma attributes, thereby indicating that DAP supplementation could promote wine fermentation performance and enhance the sensory quality of bog bilberry syrup wine.

  7. Synthesis and Thermal-Stability Study of Polybutylene Itaconate Modified with Divinyl Benzene and Glycerol

    Directory of Open Access Journals (Sweden)

    Atmanto Heru Wibowo

    2014-10-01

    Full Text Available Polybutylene itaconate (PBI for modification with divinyl benzene (DVB and glycerol has been synthesized at 180 °C for 3 h via polycondensation of itaconic acid (IA and butanediols using catalyst of Ti(OBu4. Modification on PBI was done with addition of 15%, 20% and 25% DVB (w/w using benzoyl peroxide. With glycerol, weight variations of glycerol:1,4-butanediol (BDO in the synthesis were 10%, 30%, and 50% (mole/mole. PBI and PBI modified with DVB and glycerol were characterized with FTIR and TG-DTA. PBI showed a wavenumber shift from 1703 cm-1 to 1728 cm-1 of the C=O functional group from acid to esther. The DVB modification on PBI also showed that the intensity decrease of C=C stretching was due to the formation of crosslinking on the double bond. In the modification with glycerol, three dimensional networking on the polyester occurred through bonding between hydroxyl of glycerol and acid group of IA. Constant intensity of C=C stretching on polyester was seen. The thermal stability of PBI modified with DVB increased, accompanied by rigidity change of the structure. The thermal stability of PBI modified with glycerol decreased, caused by the decrease of regularity degree and the elasticity increase of the three dimensional structure of polyester.

  8. Spontaneous quorum sensing mutation modulates electroactivity of Pseudomonas aeruginosa PA14.

    Science.gov (United States)

    Berger, Carola; Rosenbaum, Miriam A

    2017-10-01

    Pseudomonas aeruginosa is able to interact with the anode of a bioelectrochemical system through redox active phenazines. Earlier studies showed that this interaction is strain and carbon source dependent. With a spontaneously formed ΔlasR mutant of P. aeruginosa PA14 and the wildtype, we investigated the connection between the complex quorum sensing network and current production. Depending on the carbon source, phenazine production and subsequently current generation are effected differently in these two populations. In glucose-fed cultures, the lack of the LasR regulator led to a shift in phenazine concentration, relative composition, and time profiles. In contrast, with the common fermentation product 2,3-butanediol as carbon substrate, no phenazine production was detected for the ΔlasR mutant. For the wildtype, this carbon source is known to induce phenazine synthesis and elevated current production. This work supports the earlier hypothesis of a signaling link between 2,3-butanediol and the quorum-sensing regulatory system and extends this hypothesis to predict a lasR-dependent interaction. The wildtype and mutant population were also evaluated in direct competition, showing strong initial dominance of the wildtype but a higher survival rate of the ΔlasR mutant in later stages of growth. We found no evidence for strong social interactions between these two subpopulations. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. MD simulations of the binding of alcohols and diols by a calixarene in water: connections between microscopic and macroscopic properties.

    Science.gov (United States)

    Ghoufi, A; Morel, J P; Morel-Desrosiers, N; Malfreyt, P

    2005-12-15

    We report results of molecular dynamics (MD) simulations of the complexes of p-sulfonatocalix[4]arene with linear alcohols from ethanol to heptanol in water at 25 degrees C. We show that these complexes are of the inclusion type and are governed by van der Waals interactions between the calixarene cavity and the inserted alkyl chain of the alcohol. We establish a correlation between the experimental Delta(r)H degrees values and the number of atoms inserted into the calixarene cavity. We also focus on the desolvation of the host and guest to establish the importance, at the enthalpic level, of the formation of hydrogen bond bridges between the calixarene and the alcohol molecule. The fact that methanol is not complexed by p-sulfonatocalix[4]arene is explained by calculating the cost of the desolvation of the guest upon complexation. We complete this study by modeling the complexes formed with 1,4-butanediol and 1,5-pentanediol. To explain the difference between the thermodynamic properties for the binding of 1,4-butanediol and butanol, we examine the insertion rate and the solvation of each hydroxy group. We show a specific behavior of one of the two hydroxy groups at the structural and energetic levels.

  10. Starter Culture Selection for Making Chinese Sesame-Flavored Liquor Based on Microbial Metabolic Activity in Mixed-Culture Fermentation

    Science.gov (United States)

    Wu, Qun; Ling, Jie

    2014-01-01

    Selection of a starter culture with excellent viability and metabolic activity is important for inoculated fermentation of traditional food. To obtain a suitable starter culture for making Chinese sesame-flavored liquor, the yeast and bacterium community structures were investigated during spontaneous and solid-state fermentations of this type of liquor. Five dominant species in spontaneous fermentation were identified: Saccharomyces cerevisiae, Pichia membranaefaciens, Issatchenkia orientalis, Bacillus licheniformis, and Bacillus amyloliquefaciens. The metabolic activity of each species in mixed and inoculated fermentations of liquor was investigated in 14 different cocultures that used different combinations of these species. The relationships between the microbial species and volatile metabolites were analyzed by partial least-squares (PLS) regression analysis. We found that S. cerevisiae was positively correlated to nonanal, and B. licheniformis was positively associated with 2,3-butanediol, isobutyric acid, guaiacol, and 4-vinyl guaiacol, while I. orientalis was positively correlated to butyric acid, isovaleric acid, hexanoic acid, and 2,3-butanediol. These three species are excellent flavor producers for Chinese liquor. Although P. membranaefaciens and B. amyloliquefaciens were not efficient flavor producers, the addition of them alleviated competition among the other three species and altered their growth rates and flavor production. As a result, the coculture of all five dominant species produced the largest amount of flavor compounds. The result indicates that flavor producers and microbial interaction regulators are important for inoculated fermentation of Chinese sesame-flavored liquor. PMID:24814798

  11. Male sex pheromone of cockroachEurycotis floridana (walker) (Blattidae, Polyzosteriinae): Role and composition of tergites 2 and 8 secretions.

    Science.gov (United States)

    Farine, J P; Le Quere, J L; Duffy, J; Everaerts, C; Brossut, R

    1994-09-01

    InEurycotis floridana, the male calling behavior is associated with the exposition of epidermal glands located under tergites 2, 7, and 8. 4-Hydroxy-5-methyl-3(2H)-furanone and 4-hydroxy-2,5-dimethyl-3(2H)-furanone were recently identified as the specific components of tergite 7 secretion. Methylene chloride extracts of tergite 7 and its major compound 4-hydroxy-5-methyl-3(2H)-furanone attract the conspecific females at a distance. Methylene chloride extracts of tergite 8 are also attractive at a distance to the females, whereas extracts of tergite 2 had no effect on males and females. Our GC investigations showed the absence of specific compounds in tergite 2 secretions. The GC-MS analyses revealed that the male secretion of the gland under tergite 8 is mainly a mixture of (2R*, 3R*)-butanediol, 1-dodecanol and benzyl 2-hydroxybenzoate. These compounds were tested at different concentrations on their own, or as a mixture. Only (2R*, 3R*)-butanediol and 1-dodecanol were attractive for the females. Their functions, as components of the male sex pheromone, in addition with the two derivatives of the furanone are discussed.

  12. Biotechnology for producing fuels and chemicals from biomass. Volume II. Fermentation chemicals from biomass

    Energy Technology Data Exchange (ETDEWEB)

    Villet, R. (ed.)

    1981-02-01

    The technological and economic feasibility of producing some selected chemicals by fermentation is discussed: acetone, butanol, acetic acid, citric acid, 2,3-butanediol, and propionic acid. The demand for acetone and butanol has grown considerably. They have not been produced fermentatively for three decades, but instead by the oxo and aldol processes. Improved cost of fermentative production will hinge on improving yields and using cellulosic feedstocks. The market for acetic acid is likely to grow 5% to 7%/yr. A potential process for production is the fermentation of hydrolyzed cellulosic material to ethanol followed by chemical conversion to acetic acid. For about 50 years fermentation has been the chief process for citric acid production. The feedstock cost is 15% to 20% of the overall cost of production. The anticipated 5%/yr growth in demand for citric acid could be enhanced by using it to displace phosphates in detergent manufacture. A number of useful chemicals can be derived from 2,3-butanediol, which has not been produced commercially on a large scale. R and D are needed to establish a viable commercial process. The commercial fermentative production of propionic acid has not yet been developed. Recovery and purification of the product require considerable improvement. Other chemicals such as lactic acid, isopropanol, maleic anhydride, fumarate, and glycerol merit evaluation for commercial fermentative production in the near future.

  13. Reduction of ethanol yield and improvement of glycerol formation by adaptive evolution of the wine yeast Saccharomyces cerevisiae under hyperosmotic conditions.

    Science.gov (United States)

    Tilloy, Valentin; Ortiz-Julien, Anne; Dequin, Sylvie

    2014-04-01

    There is a strong demand from the wine industry for methodologies to reduce the alcohol content of wine without compromising wine's sensory characteristics. We assessed the potential of adaptive laboratory evolution strategies under hyperosmotic stress for generation of Saccharomyces cerevisiae wine yeast strains with enhanced glycerol and reduced ethanol yields. Experimental evolution on KCl resulted, after 200 generations, in strains that had higher glycerol and lower ethanol production than the ancestral strain. This major metabolic shift was accompanied by reduced fermentative capacities, suggesting a trade-off between high glycerol production and fermentation rate. Several evolved strains retaining good fermentation performance were selected. These strains produced more succinate and 2,3-butanediol than the ancestral strain and did not accumulate undesirable organoleptic compounds, such as acetate, acetaldehyde, or acetoin. They survived better under osmotic stress and glucose starvation conditions than the ancestral strain, suggesting that the forces that drove the redirection of carbon fluxes involved a combination of osmotic and salt stresses and carbon limitation. To further decrease the ethanol yield, a breeding strategy was used, generating intrastrain hybrids that produced more glycerol than the evolved strain. Pilot-scale fermentation on Syrah using evolved and hybrid strains produced wine with 0.6% (vol/vol) and 1.3% (vol/vol) less ethanol, more glycerol and 2,3-butanediol, and less acetate than the ancestral strain. This work demonstrates that the combination of adaptive evolution and breeding is a valuable alternative to rational design for remodeling the yeast metabolic network.

  14. Glycerol Overproduction by Engineered Saccharomyces cerevisiae Wine Yeast Strains Leads to Substantial Changes in By-Product Formation and to a Stimulation of Fermentation Rate in Stationary Phase

    Science.gov (United States)

    Remize, F.; Roustan, J. L.; Sablayrolles, J. M.; Barre, P.; Dequin, S.

    1999-01-01

    Six commercial wine yeast strains and three nonindustrial strains (two laboratory strains and one haploid strain derived from a wine yeast strain) were engineered to produce large amounts of glycerol with a lower ethanol yield. Overexpression of the GPD1 gene, encoding a glycerol-3-phosphate dehydrogenase, resulted in a 1.5- to 2.5-fold increase in glycerol production and a slight decrease in ethanol formation under conditions simulating wine fermentation. All the strains overexpressing GPD1 produced a larger amount of succinate and acetate, with marked differences in the level of these compounds between industrial and nonindustrial engineered strains. Acetoin and 2,3-butanediol formation was enhanced with significant variation between strains and in relation to the level of glycerol produced. Wine strains overproducing glycerol at moderate levels (12 to 18 g/liter) reduced acetoin almost completely to 2,3-butanediol. A lower biomass concentration was attained by GPD1-overexpressing strains, probably due to high acetaldehyde production during the growth phase. Despite the reduction in cell numbers, complete sugar exhaustion was achieved during fermentation in a sugar-rich medium. Surprisingly, the engineered wine yeast strains exhibited a significant increase in the fermentation rate in the stationary phase, which reduced the time of fermentation. PMID:9872772

  15. Single-walled carbon nanotube-based polymer monoliths for the enantioselective nano-liquid chromatographic separation of racemic pharmaceuticals.

    Science.gov (United States)

    Ahmed, Marwa; Yajadda, Mir Massoud Aghili; Han, Zhao Jun; Su, Dawei; Wang, Guoxiu; Ostrikov, Kostya Ken; Ghanem, Ashraf

    2014-09-19

    Single-walled carbon nanotubes were encapsulated into different polymer-based monolithic backbones. The polymer monoliths were prepared via the copolymerization of 20% monomers, glycidyl methacrylate, 20% ethylene glycol dimethacrylate and 60% porogens (36% 1-propanol, 18% 1,4-butanediol) or 16.4% monomers (16% butyl methacrylate, 0.4% sulfopropyl methacrylate), 23.6% ethylene glycol dimethacrylate and 60% porogens (36% 1-propanol, 18% 1,4-butanediol) along with 6% single-walled carbon nanotubes aqueous suspension. The effect of single-walled carbon nanotubes on the chiral separation of twelve classes of pharmaceutical racemates namely; α- and β-blockers, antiinflammatory drugs, antifungal drugs, dopamine antagonists, norepinephrine-dopamine reuptake inhibitors, catecholamines, sedative hypnotics, diuretics, antihistaminics, anticancer drugs and antiarrhythmic drugs was investigated. The enantioselective separation was carried out under multimodal elution to explore the chiral recognition capabilities of single-walled carbon nanotubes using reversed phase, polar organic and normal phase chromatographic conditions using nano-liquid chromatography. Baseline separation was achieved for celiprolol, chlorpheniramine, etozoline, nomifensine and sulconazole under multimodal elution conditions. Satisfactory repeatability was achieved through run-to-run, column-to-column and batch-to-batch investigations. Our findings demonstrate that single-walled carbon nanotubes represent a promising stationary phase for the chiral separation and may open the field for a new class of chiral selectors. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

  16. Enhanced production of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer and antimicrobial yellow pigmentation from Cupriavidus sp. USMAHM13 with antibiofilm capability.

    Science.gov (United States)

    Ismail, Iszatty; Gurusamy, Tana Poorani; Ramachandran, Hema; Al-Ashraf Amirul, Abdullah

    2017-04-21

    Antibiofilm polymers have the ability to inhibit bacterial biofilm formation, which is known to occur ubiquitously in the environment and pose risks of infection. In this study, production of P(3HB-co-4HB) copolymer and antimicrobial yellow pigment from Cupriavidus sp. USMAHM13 are enhanced through medium optimization. Before the improvement of yellow pigment production, screening for the best additional supplement was performed resulting in high-yield yellow pigmentation using yeast extract with optimum concentration of 2 g/L. Effects of different concentrations of 1,4-butanediol, ammonium acetate, and yeast extract were studied using central composite design. Under optimal conditions, 53 wt% of polyhydroxyalkanoate (PHA) content, 0.35 g/L of pigment concentration, and 5.87 g/L of residual biomass were achieved at 0.56 wt% C of 1,4-butanediol, 1.14 g/L of ammonium acetate, and 2 g/L of yeast extract. Antibiofilm tests revealed that the yellow pigment coated on P(3HB-co-4HB) copolymer had significant effect on the inhibition of bacteria proliferation and colonization from 6 hr onward reaching 100% inhibition by 12 hr, hence effectively inhibiting the biofilm formation.

  17. Performance of supercritical methanol in polyurethane degradation

    Directory of Open Access Journals (Sweden)

    Liu Lu

    2016-01-01

    Full Text Available Polyurethane is a group of block copolymer which is composed of diisocyanate, chain extender, and polyol, including polyurethane foam, polyurethane elastomer, waterborne polyurethane, etc. This research focused on thermoplastic polyurethane elastomer (TPU which is formed with 4,4’-diphenylmethane diisocyanate (MDI, poly(1,4-butanediol-hexanedioic acid diolpolyester(PBA and extended with 1,4-butanediol(BDO.The degradation of TPU was carried out with the help of methanol as the supercritical solvent. The SEM of the reaction residues revealed the process of the depolymerisation. The products were measured by GC-MS and found out to be PBA, BDO and 4,4’-methylene diphenyl carbamate(MDC which is themethylate of MDI.GC-FID, HPLC-UV and GPC were used to further analysis. The experimental results showed that supercritical methanol performed outstandingly in TPU recycling, it needed lower temperature and shorter time than regular methods. At 230°C/70min, over 90% raw materials of TPU could be recovered.

  18. The Japan Flavour and Fragrance Materials Association's (JFFMA) safety assessment of acetal food flavouring substances uniquely used in Japan.

    Science.gov (United States)

    Okamura, Hiroyuki; Abe, Hajime; Hasegawa-Baba, Yasuko; Saito, Kenji; Sekiya, Fumiko; Hayashi, Shim-Mo; Mirokuji, Yoshiharu; Maruyama, Shinpei; Ono, Atsushi; Nakajima, Madoka; Degawa, Masakuni; Ozawa, Shogo; Shibutani, Makoto; Maitani, Tamio

    2015-01-01

    Using the procedure devised by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), we performed safety evaluations on five acetal flavouring substances uniquely used in Japan: acetaldehyde 2,3-butanediol acetal, acetoin dimethyl acetal, hexanal dibutyl acetal, hexanal glyceryl acetal and 4-methyl-2-pentanone propyleneglycol acetal. As no genotoxicity study data were available in the literature, all five substances had no chemical structural alerts predicting genotoxicity. Using Cramer's classification, acetoin dimethyl acetal and hexanal dibutyl acetal were categorised as class I, and acetaldehyde 2,3-butanediol acetal, hexanal glyceryl acetal and 4-methyl-2-pentanone propyleneglycol acetal as class III. The estimated daily intakes for all five substances were within the range of 1.45-6.53 µg/person/day using the method of maximised survey-derived intake based on the annual production data in Japan from 2001, 2005, 2008 and 2010, and 156-720 µg/person/day using the single-portion exposure technique (SPET), based on the average use levels in standard portion sizes of flavoured foods. The daily intakes of the two class I substances were below the threshold of toxicological concern (TTC) - 1800 μg/person/day. The daily intakes of the three class III substances exceeded the TTC (90 μg/person/day). Two of these, acetaldehyde 2,3-butanediol acetal and hexanal glyceryl acetal, were expected to be metabolised into endogenous products after ingestion. For 4-methyl-2-pentanone propyleneglycol acetal, one of its metabolites was not expected to be metabolised into endogenous products. However, its daily intake level, based on the estimated intake calculated by the SPET method, was about 1/15 000th of the no observed effect level. It was thus concluded that all five substances raised no safety concerns when used for flavouring foods at the currently estimated intake levels. While no information on in vitro and in vivo toxicity for all five substances was available

  19. The small angle neutron scattering study on the segmented polyurethane

    Energy Technology Data Exchange (ETDEWEB)

    Sudirman; Gunawan; Prasetyo, S.M.; Karo Karo, A.; Lahagu, I.M.; Darwinto, Tri [Materials Science Research Center, National Nuclear Energy Agency, Serpong, Tangerang (Indonesia)

    1999-10-01

    The distance between hard segment (HS) and soft segment (SS) of segmented polyurethane have been determined using the Small Angle Neutron Scattering (SANS) technique. The segmented Polyurethanes (SPU) are linear multiblock copolymers, which include elastomer thermoplastic. SPU consist of hard segment and soft segment, each has tendency to make a group with similar type to form a domain. The soft segments used were polypropylene glycol (PPG) and 4,4 diphenylmethane diisocyanate (MDI), while l,4 butanediol (BD) was used as hard segment. The characteristic of SPU depends on its phase structure which is affected by several factors, such as type of chemical formula and the composition of the HS and SS, solvent as well as the synthesizing process. The samples used in this study were SPU56 and SPU68. Based on the appearance of SANS profile, it was obtained that domain distances are 12.32 nm for the SPU56 and 19 nm for the SPU68. (author)

  20. Energy and chemicals from the selective electrooxidation of renewable diols by organometallic fuel cells.

    Science.gov (United States)

    Bellini, Marco; Bevilacqua, Manuela; Filippi, Jonathan; Lavacchi, Alessandro; Marchionni, Andrea; Miller, Hamish A; Oberhauser, Werner; Vizza, Francesco; Annen, Samuel P; Grützmacher, H

    2014-09-01

    Organometallic fuel cells catalyze the selective electrooxidation of renewable diols, simultaneously providing high power densities and chemicals of industrial importance. It is shown that the unique organometallic complex [Rh(OTf)(trop2NH)(PPh3)] employed as molecular active site in an anode of an OMFC selectively oxidizes a number of renewable diols, such as ethylene glycol , 1,2-propanediol (1,2-P), 1,3-propanediol (1,3-P), and 1,4-butanediol (1,4-B) to their corresponding mono-carboxylates. The electrochemical performance of this molecular catalyst is discussed, with the aim to achieve cogeneration of electricity and valuable chemicals in a highly selective electrooxidation from diol precursors. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Features of the sorption redistribution of hydrocarbons and alcohols in a gas-supramolecular liquid crystal system

    Science.gov (United States)

    Onuchak, L. A.; Ukolova, D. A.; Burmatnova, T. S.; Kuraeva, Yu. G.; Kuvshinova, S. A.; Burmistrov, V. A.; Stepanova, R. F.

    2015-01-01

    Thermodynamic characteristics of the sorption redistribution of hydrocarbons (C8-C12 n-alkanes, C10H16 terpenes, xylene isomers) and alcohols (C3-C5 alkanols, butanediol-2,3, menthol) in a gas-4-(3-hydroxypropyloxy)-4'-formylazobenzene (HPOFAB) supramolecular smectic-nematic liquid crystal system are studied via inverse gas chromatography. The sorption capacity of HPOFAB with respect to nonmesogene sorbates is found to be strongly diminished due to its associated structure, especially in the smectic A phase. Great positive deviations from the Raoult law in the studied nonmesogene-HPOFAB systems are observed not only in mesophases, but also in the isotropic HPOFAB phase, which has a high selectivity to para- and meta-xylenes, in contrast to the isotropic phases of classic (non-associated) liquid crystals.

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

    Science.gov (United States)

    Vlad, Elena; Bozga, Grigore

    2012-01-01

    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. PMID:23365512

  3. Carbon recycling by cyanobacteria: improving CO2 fixation through chemical production.

    Science.gov (United States)

    Zhang, Angela; Carroll, Austin L; Atsumi, Shota

    2017-09-01

    Atmospheric CO2 levels have reached an alarming level due to industrialization and the burning of fossil fuels. In order to lower the level of atmospheric carbon, strategies to sequester excess carbon need to be implemented. The CO2-fixing mechanism in photosynthetic organisms enables integration of atmospheric CO2 into biomass. Additionally, through exogenous metabolic pathways in these photosynthetic organisms, fixed CO2 can be routed to produce various commodity chemicals that are currently produced from petroleum. This review will highlight studies and modifications to different components of cyanobacterial CO2-fixing systems, as well as the application of these systems toward CO2-derived chemical production. 2,3-Butanediol is given particular focus as one of the most thoroughly studied systems for conversion of CO2 to a bioproduct. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Liquefaction of kenaf (Hibiscus cannabinus L.) core for wood laminating adhesive.

    Science.gov (United States)

    Juhaida, M F; Paridah, M T; Mohd Hilmi, M; Sarani, Z; Jalaluddin, H; Mohamad Zaki, A R

    2010-02-01

    A study was carried out to produce polyurethane (PU) as a wood laminating adhesive from liquefied kenaf core (LKC) polyols by reacting it with toluene-2,4-diisocyanate (TDI) and 1,4-butanediol (BDO). The LKC polyurethane (LKCPU) adhesive has a molecular weight (MW) of 2666, viscosity of 5370 mPa s, and solids content of 86.9%. The average shear strength of the rubberwood (RW) bonded with LKCPU adhesive was 2.9 MPa. Most of the sheared specimens experienced a total adhesive failure. The formation of air bubbles through the liberation of carbon dioxide was observed to reduce the adhesive penetration and bonding strength which was obviously seen on the sheared specimens. The percentage of catalyst used can be varied based on the usage and working time needed. Nonetheless, the physical properties of LKCPU produced in this work had shown good potential as edge-bonding adhesive.

  5. Synthesis and characterization of polyurethane/bentonite nanoclay based nanocomposites using different diisocyanates: relation between mechanical and thermal properties

    Science.gov (United States)

    Bocchio, Javier; Wittemberg, Víctor; Quagliano, Javier

    2017-05-01

    Polyurethanes (PUs) and polyurethane nanocomposites (PUNC) with bentonite nanoclay were prepared by the reaction of toluene-2,4-diisocyanate (TDI), dimeryl diisocyanate (DDI) and isophorone diisocyanate (IPDI) with two different polymers: hydroxyl terminated polybutadiene (HTPB) and polytetramethylene ether glycol (PTMEG), and the chains were further extended with 1,4-butanediol (1,4-BDO) to get final PUs and PUNCs. PUNCs were prepared by dispersing within the polymers a commercial and a synthesized bentonite nanoclay by mechanical dispersion. Mechanical properties showed that the addition of a small amount of nanoclay resulted in a significant increase in tensile strength and reduction in elongation at break (maximum increase of 2.3 and 5-times reduction, respectively, for a HTPB-TDI-BDO PUNCs). Thermal analysis revealed that the addition of nanoclays improved the thermal stability and increased decomposition temperature of PUNCs. We concluded that there is a positive correlation between mechanical and thermal properties as a result of nanoclay addition.

  6. Manipulation of morphology and magnetic properties in cobalt nanowires

    Science.gov (United States)

    Li, Chenglin; Wu, Qiong; Yue, Ming; Xu, Huanhuan; Palaka, Subhashini; Elkins, Kevin; Ping Liu, J.

    2017-05-01

    Ferromagnetic metallic Cobalt nanowires are synthesized by the reduction of carboxylate salts of Co in 1, 2-butanediol using a solvothermal chemical process. In this process, the size and shape of the nanocrystals can be controlled via reaction parameters such as surfactant ratio, precursor concentration, and the temperature ramp. Synthesized Co nanocrystals exhibit the hexagonally close-packed phase favored the growth of anisotropic particles and the (002) crystalline direction is along the long axis of the nanowires. By varying the catalyst concentration in proper range, the effect of synthetic parameters on controlling Co nanoparticles with different length of 50 - 700 nm was systematically studied. Magnetic measurements and TEM images of the Cobalt nanowires indicate that the coercivity of the Co nanowires depends substantially on the morphology. The obtained highest coercivity of 8.4 kOe can be attributed to their small mean diameter and high crystallinity of nanowires for 200 - 300 nm.

  7. Manipulation of morphology and magnetic properties in cobalt nanowires

    Directory of Open Access Journals (Sweden)

    Chenglin Li

    2017-05-01

    Full Text Available Ferromagnetic metallic Cobalt nanowires are synthesized by the reduction of carboxylate salts of Co in 1, 2-butanediol using a solvothermal chemical process. In this process, the size and shape of the nanocrystals can be controlled via reaction parameters such as surfactant ratio, precursor concentration, and the temperature ramp. Synthesized Co nanocrystals exhibit the hexagonally close-packed phase favored the growth of anisotropic particles and the (002 crystalline direction is along the long axis of the nanowires. By varying the catalyst concentration in proper range, the effect of synthetic parameters on controlling Co nanoparticles with different length of 50 - 700 nm was systematically studied. Magnetic measurements and TEM images of the Cobalt nanowires indicate that the coercivity of the Co nanowires depends substantially on the morphology. The obtained highest coercivity of 8.4 kOe can be attributed to their small mean diameter and high crystallinity of nanowires for 200 - 300 nm.

  8. Thermal stability of segmented polyurethane elastomers reinforced by clay particles

    Directory of Open Access Journals (Sweden)

    Pavličević Jelena

    2009-01-01

    Full Text Available The aim of this work was to determine the influence of clay nanoparticles on thermal properties of segmented polyurethanes based on hexamethylene- diisocyanate, aliphatic polycarbonate diol and 1,4-butanediol as chain extender. The organically modified particles of montmorillonite and bentonite were used as reinforcing fillers. The structure of elastomeric materials was varied either by diol type or chain extender content. The ratio of OH groups from diol and chain extender (R was either 1 or 10. Thermal properties of prepared materials were determined using modulated differential scanning calorimetry (MDSC. Thermal stability of obtained elastomers has been studied by simultaneously thermogravimetry coupled with DSC. The glass transition temperature, Tg, of soft segments for all investigated samples was about -33°C. On the basis of DTG results, it was concluded that obtained materials were very stable up to 300°C.

  9. Effects of introducing heterologous pathways on microbial metabolism with respect to metabolic optimality

    DEFF Research Database (Denmark)

    Kim, Hyun Uk; Kim, Byoungjin; Seung, Do Young

    2014-01-01

    Although optimality of microbial metabolism under genetic and environmental perturbations is well studied, the effects of introducing heterologous reactions on the overall metabolism are not well understood. This point is important in the field of metabolic engineering because heterologous...... reactions are more frequently introduced into various microbial hosts. The genome-scale metabolic simulations of Escherichia coli strains engineered to produce 1,4-butanediol, 1,3-propanediol, and amorphadiene suggest that microbial metabolism shows much different responses to the introduced heterologous...... as engineering targets in systems metabolic engineering strategies. To our knowledge, this study is the first attempt to quantitatively characterize microbial metabolisms with different heterologous reactions. The suggested potential reasons behind each strain’s different metabolic responses to the introduced...

  10. Synthesis, Properties and Applications of Biodegradable Polymers Derived from Diols and Dicarboxylic Acids: From Polyesters to Poly(ester amides

    Directory of Open Access Journals (Sweden)

    Angélica Díaz

    2014-04-01

    Full Text Available Poly(alkylene dicarboxylates constitute a family of biodegradable polymers with increasing interest for both commodity and speciality applications. Most of these polymers can be prepared from biobased diols and dicarboxylic acids such as 1,4-butanediol, succinic acid and carbohydrates. This review provides a current status report concerning synthesis, biodegradation and applications of a series of polymers that cover a wide range of properties, namely, materials from elastomeric to rigid characteristics that are suitable for applications such as hydrogels, soft tissue engineering, drug delivery systems and liquid crystals. Finally, the incorporation of aromatic units and α-amino acids is considered since stiffness of molecular chains and intermolecular interactions can be drastically changed. In fact, poly(ester amides derived from naturally occurring amino acids offer great possibilities as biodegradable materials for biomedical applications which are also extensively discussed.

  11. Preparation of CoFe2O4/SiO2 Nanocomposites at Low Temperatures Using Short Chain Diols

    Directory of Open Access Journals (Sweden)

    Thomas Dippong

    2017-01-01

    Full Text Available The preparation of 70% CoFe2O4/30% SiO2 (wt% nanocomposites by sol-gel method using three short chain diols (1,2-ethanediol, 1,3-propanediol, and 1,4-butanediol as chelators was studied. The Fourier transformed infrared spectra and X-ray diffraction patterns were used to confirm the formation of nanocomposites. The X-ray diffraction analysis showed that the chain length of the carboxylates embedded in the silica matrix influences the formation of crystallized cobalt ferrite as single phase at low temperatures. The influence of the methylene groups number in the precursors and annealing temperature on the nanocrystallite size was revealed. The stability of the obtained compounds was determined by calculation of thermodynamic parameters.

  12. UV-polymerized butyl methacrylate monoliths with embedded carboxylic single-walled carbon nanotubes for CEC applications.

    Science.gov (United States)

    Navarro-Pascual-Ahuir, María; Lucena, Rafael; Cárdenas, Soledad; Ramis-Ramos, Guillermo; Valcárcel, Miguel; Herrero-Martínez, José Manuel

    2014-10-01

    The preparation of polymeric monoliths with embedded carboxy-modified single-walled carbon nanotubes (c-SWNTs) and their use for capillary electrochromatography (CEC) is described. Carbon nanotube composites were obtained by preparing a polymerization mixture in the presence of increasing c-SWNT concentrations, followed by UV initiation. The novel stationary phases were studied by optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Using short UV-polymerization times, the optimized porogenic solvent (a binary mixture of 1,4-butanediol and 2-propanol) gave rise to polymeric beds with homogenously dispersed embedded c-SWNTs. The CEC features of these monoliths were evaluated using polycyclic aromatic hydrocarbons (PAHs), non-steroidal anti-inflammatory drugs (NSAIDs) and chiral compounds. The monolith prepared in the presence of c-SWNTs showed enhanced resolution of the text mixtures, including a remarkable capability to separate enantiomers.

  13. Evaluation of biodegradation of bioplastics in swa water. Kaisuichu ni okeru bio plastic no seibunkaisei no hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Doi, Y. (Tokyo Institute of Technology, Tokyo (Japan))

    1991-07-01

    Research and development have been pursued of plastic materials degradable in sea water and their application to the fishery material field in consideration of protection of the marine environment. Tests are conducted on degradation speed of bioplastics in sea water. Concerning a sample copolymeric polyester, by giving 4-hydroxy butyric acid, 1,4-butanediol, 1,6-hexanediol and {gamma}-a butyrolactone group to A.eutrophus, copolymeric polyester P (3HB-co-4HB), a mixture of molecular units of 3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB) is fermented. Test results show that it degrades at the same speed, being independent of molecular structures of biopolyester and copolymerization composition, different from the case of degradation in soil. It is clarified that the microorganism which degrades biopolyester in sea water is streptomyces, a kind of actinomycetes. 3 refs., 5 figs.

  14. Effects of Polybenzoxazine on Shape Memory Properties of Polyurethanes with Amorphous and Crystalline Soft Segments

    Directory of Open Access Journals (Sweden)

    Senlong Gu

    2014-04-01

    Full Text Available This paper evaluates the role of minor component polybenzoxazine (PB on shape-memory properties of polyurethanes (PU with glassy and crystalline soft segments. The polymer compounds were prepared in two steps. In the first step, benzoxazine, polyurethane pre-polymer, and chain extender butanediol (BD were mixed into a solution followed by chain-extension of the pre-polymer with BD. In the second step, benzoxazine was polymerized at 180 °C for 3 h to obtain shape memory polymer compounds. The atomic force microscopy images revealed that the PB-phase formed uniform dispersions in PU. The presence of PB-phase induced shape-memory behavior in non-shape memory PU with amorphous soft segment and significantly improved the values of shape fixity, recovery ratio, and recovery stress in shape memory polyurethane with crystalline soft segment.

  15. Synthesis and Characterization of Anionic Polyester-Polyurethane Dispersion as Environmentally-Friendly Waterbased Resins

    Directory of Open Access Journals (Sweden)

    Najaf i F. Manouchehri F., and Shaabanz

    2012-01-01

    Full Text Available Aqueous polyurethane dispersions (PUDs have recently emerged as important alternatives to their solvent-based counterparts for various applications due to increasing health and environmental awareness (green chemistry. Anionic polyester-polyurethane dispersions were synthesized by three steps. In the first step, macromonomer diisocyanate having carboxylic acid was prepared by isophorone diisocyanate (IPDI, dimethylol propionic acid (DMPA in percent of acetone as solvent and dibutyldtin dilaurate (DBTDL as catalyst. Then, carboxylic polyurethane was prepared by reaction macromonomer diisocyanate having carboxylic acid with linear aliphatic polyester (Mw=2000, trifunctional polyester (Mw=2800 and butanediol (BDO as chain extender. The next step involved neutralization and dispersion in water, where acidic polyurethane was neutralized by the addition of triethylamine (TEA.  Factors influencing the synthesis of polyurethane dispersion mainly involve reaction temperature, reaction time, the concentration of catalyst, DMPA content and BDO content, were studied. The polymers have been characterized with DSC and FTIR.

  16. Nucleic acid compositions and the encoding proteins

    Science.gov (United States)

    Preston, III, James F.; Chow, Virginia; Nong, Guang; Rice, John D.; St. John, Franz J.

    2014-09-02

    The subject invention provides at least one nucleic acid sequence encoding an aldouronate-utilization regulon isolated from Paenibacillus sp. strain JDR-2, a bacterium which efficiently utilizes xylan and metabolizes aldouronates (methylglucuronoxylosaccharides). The subject invention also provides a means for providing a coordinately regulated process in which xylan depolymerization and product assimilation are coupled in Paenibacillus sp. strain JDR-2 to provide a favorable system for the conversion of lignocellulosic biomass to biobased products. Additionally, the nucleic acid sequences encoding the aldouronate-utilization regulon can be used to transform other bacteria to form organisms capable of producing a desired product (e.g., ethanol, 1-butanol, acetoin, 2,3-butanediol, 1,3-propanediol, succinate, lactate, acetate, malate or alanine) from lignocellulosic biomass.

  17. Complete genome sequence of the drought resistance-promoting endophyte Klebsiella sp. LTGPAF-6F.

    Science.gov (United States)

    Zhang, Lei; Zhong, Jun; Liu, Hao; Xin, Kaiyun; Chen, Chaoqiong; Li, Qiqi; Wei, Yahong; Wang, Yao; Chen, Fei; Shen, Xihui

    2017-03-20

    Bacterial endophytes with capacity to promote plant growth and improve plant tolerance against biotic and abiotic stresses have importance in agricultural practice and phytoremediation. A plant growth-promoting endophyte named Klebsiella sp. LTGPAF-6F, which was isolated from the roots of the desert plant Alhagi sparsifolia in north-west China, exhibits the ability to enhance the growth of wheat under drought stress. The complete genome sequence of this strain consists of one circular chromosome and two circular plasmids. From the genome, we identified genes related to the plant growth promotion and stress tolerance, such as nitrogen fixation, production of indole-3-acetic acid, acetoin, 2,3-butanediol, spermidine and trehalose. This genome sequence provides a basis for understanding the beneficial interactions between LTGPAF-6F and host plants, and will facilitate its applications as biotechnological agents in agriculture. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. 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.

  19. Synthesis and characterization of hyaluronic acid/human-like collagen hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jingjing; Ma, Xiaoxuan, E-mail: xiaoxuanma@163.com; Fan, Daidi, E-mail: fandaidi@nwu.edu.cn; Zhu, Chenhui; Deng, Jianjun; Hui, Junfeng; Ma, Pei

    2014-10-01

    Injectable hydrogel plays an important role in soft tissue filling and repair. We report an injectable hydrogel based on hyaluronic acid (HA) and human-like collagen (HLC), both with favorable biocompatibility and biodegradability. These two types of biomacromolecules were crosslinked with 1,4-butanediol diglycidyl ether to form a three-dimensional network. The redundant crosslinker was removed by dialysis and distillation. An HA-based hydrogel prepared by the same method was used as a control. The cytocompatibility was studied with a Cell Counting Kit-8 (CCK-8) test. Carbazole colorimetry was used to analyze the in vitro degradation rate. The histocompatibility was evaluated by hematoxylin and eosin (H and E) staining analysis and immunohistochemical analysis. The CCK-8 assay demonstrated that the HA/HLC hydrogel was less cytotoxic than the HA-based hydrogel and could promote baby hamster kidney cell (BHK) proliferation. The cell adhesion indicated that BHK could grow well on the surface of the materials and maintain good cell viability. The in vitro degradation test showed that the HA/HLC hydrogel had a longer degradation time and an excellent antienzyme ability. In vivo injection showed that there was little inflammatory response to HA/HLC after 1, 2, and 4 weeks. Therefore, the HA/HLC hydrogel is a promising biomaterial for soft tissue filling and repair. - Highlights: • Human-like collagen was used with hyaluronic acid to prepare soft tissue filling meterials. • 1,4-Butanediol diglycidyl ether (BDDE) was introduced to treat the hydrogels. • The addition of human-like collagen could improve the biological properties of hydrogels.

  20. Degradation of di(2-ethyl hexyl) phthalate by Fusarium culmorum: Kinetics, enzymatic activities and biodegradation pathway based on quantum chemical modelingpathway based on quantum chemical modeling

    Energy Technology Data Exchange (ETDEWEB)

    Ahuactzin-Pérez, Miriam [Doctorado en Biología Experimental, Universidad Autónoma Metropolitana-Iztapalapa (UAM-I) (Mexico); Facultad de Agrobiología, Universidad Autónoma de Tlaxcala, Ixtacuixtla, Tlaxcala (Mexico); Tlecuitl-Beristain, Saúl; García-Dávila, Jorge [Universidad Politécnica de Tlaxcala, San Pedro Xalcatzinco, Tepeyanco, Tlaxcala CP 90180 (Mexico); González-Pérez, Manuel [Universidad Popular Autónoma del Estado de Puebla, Puebla CP 72410 (Mexico); Gutiérrez-Ruíz, María Concepción [Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana-Iztapalapa, D.F (Mexico); Sánchez, Carmen, E-mail: sanher6@hotmail.com [Laboratory of Biotechnology, Research Centre for Biological Sciences, Universidad Autónoma de Tlaxcala, Ixtacuixtla, Tlaxcala CP. 90062 (Mexico)

    2016-10-01

    Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer widely used in the manufacture of plastics, and it is an environmental contaminant. The specific growth rate (μ), maximum biomass (X{sub max}), biodegradation constant of DEHP (k), half-life (t{sub 1/2}) of DEHP biodegradation and removal efficiency of DEHP, esterase and laccase specific activities, and enzymatic yield parameters were evaluated for Fusarium culmorum grown on media containing glucose and different concentrations of DEHP (0, 500 and 1000 mg/L). The greatest μ and the largest X{sub max} occurred in media supplemented with 1000 mg of DEHP/L. F. culmorum degraded 95% of the highest amount of DEHP tested (1000 mg/L) within 60 h of growth. The k and t{sub 1/2} were 0.024 h{sup −1} and 28 h, respectively, for both DEHP concentrations. The removal efficiency of DEHP was 99.8% and 99.9% for 1000 and 500 mg/L, respectively. Much higher specific esterase activity than specific laccase activity was observed in all media tested. The compounds of biodegradation of DEHP were identified by GC–MS. A DEHP biodegradation pathway by F. culmorum was proposed on the basis of the intermolecular flow of electrons of the identified intermediate compounds using quantum chemical modeling. DEHP was fully metabolized by F. culmorum with butanediol as the final product. This fungus offers great potential in bioremediation of environments polluted with DEHP. - Highlights: • F. culmorum degraded 95% of DEHP (1000 mg/L) within 60 h. • Removal efficiency of DEHP was 99.8% and 99.9% for 1000 and 500 mg/L, respectively. • DEHP was fully metabolized by F. culmorum, with butanediol as the final product. • A DEHP biodegradation pathway was proposed using on quantum chemical modeling.

  1. Three-dimensional nonwoven scaffolds from a novel biodegradable poly(ester amide) for tissue engineering applications.

    Science.gov (United States)

    Hemmrich, Karsten; Salber, Jochen; Meersch, Melanie; Wiesemann, Ute; Gries, Thomas; Pallua, Norbert; Klee, Doris

    2008-01-01

    Biodegradable polyesters are established biomaterials in medicine due to their chemical characteristics and options for material processing. A main problem, however, is the release of acid degradation products during biodegradation with severe local pH-drops and inflammatory reactions. Polyesteramides, in contrast, show a less prominent pH-drop during degradation. In this study, we developed a simple, reproducible synthesis of the poly(ester amide) (PEA) type C starting from epsilon-caprolactame, 1,4-butanediol, and adipic acid in a one-batch two-step reaction and conducted the manufacturing of PEA-derived 3D textile scaffolds applicable for tissue engineering purposes. The thermal and mechanical properties of PEA-type C were analysed and the structural conformity of different batches was confirmed by NMR spectroscopy and size exclusion chromatography. The polymer was formed into nonwovens by textile manufacturing. Cytotoxicity tests and X-ray photoelectron spectroscopy (XPS) were used to analyze the effect of scaffold extraction before cell seeding. The manufactured carriers were seeded with human preadipocytes and examined for cellular proliferation and differentiation. The production of PEA type C successfully occurred via simultaneous ring-opening polymerization of epsilon-caprolactame and polycondensation with 1,4-butanediol and adipic acid at 250 degrees C under high-vacuum. Soxhlet extraction allowed optimal cleaning of nonwoven scaffolds. Extracted PEA-derived matrices were capable of allowing good adherence, proliferation, and differentiation of preadipocytes. These results are encouraging and guidance towards an optimally prepared nonwoven carrier applicable for clinical use.

  2. Harnessing the respiration machinery for high-yield production of chemicals in metabolically engineered Lactococcus lactis.

    Science.gov (United States)

    Liu, Jianming; Wang, Zhihao; Kandasamy, Vijayalakshmi; Lee, Sang Yup; Solem, Christian; Jensen, Peter Ruhdal

    2017-11-01

    When modifying the metabolism of living organisms with the aim of achieving biosynthesis of useful compounds, it is essential to ensure that it is possible to achieve overall redox balance. We propose a generalized strategy for this, based on fine-tuning of respiration. The strategy was applied on metabolically engineered Lactococcus lactis strains to optimize the production of acetoin and (R,R)-2,3-butanediol (R-BDO). In the absence of an external electron acceptor, a surplus of two NADH per acetoin molecule is produced. We found that a fully activated respiration was able to efficiently regenerate NAD+, and a high titer of 371mM (32g/L) of acetoin was obtained with a yield of 82% of the theoretical maximum. Subsequently, we extended the metabolic pathway from acetoin to R-BDO by introducing the butanediol dehydrogenase gene from Bacillus subtilis. Since one mole of NADH is consumed when acetoin is converted into R-BDO per mole, only the excess of NADH needs to be oxidized via respiration. Either by fine-tuning the respiration capacity or by using a dual-phase fermentation approach involving a switch from fully respiratory to non-respiratory conditions, we obtained 361mM (32g/L) R-BDO with a yield of 81% or 365mM (33g/L) with a yield of 82%, respectively. These results demonstrate the great potential in using finely-tuned respiration machineries for bio-production. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  3. Effects of Eliminating Pyruvate Node Pathways and of Coexpression of Heterogeneous Carboxylation Enzymes on Succinate Production by Enterobacter aerogenes

    Science.gov (United States)

    Yamamoto, Yoko; Fukui, Keita; Nishio, Yousuke; Hashiguchi, Kenichi; Usuda, Yoshihiro; Sode, Koji

    2014-01-01

    Lowering the pH in bacterium-based succinate fermentation is considered a feasible approach to reduce total production costs. Newly isolated Enterobacter aerogenes strain AJ110637, a rapid carbon source assimilator under weakly acidic (pH 5.0) conditions, was selected as a platform for succinate production. Our previous work showed that the ΔadhE/PCK strain, developed from AJ110637 with inactivated ethanol dehydrogenase and introduced Actinobacillus succinogenes phosphoenolpyruvate carboxykinase (PCK), generated succinate as a major product of anaerobic mixed-acid fermentation from glucose under weakly acidic conditions (pH <6.2). To further improve the production of succinate by the ΔadhE/PCK strain, metabolically engineered strains were designed based on the elimination of pathways that produced undesirable products and the introduction of two carboxylation pathways from phosphoenolpyruvate and pyruvate to oxaloacetate. The highest production of succinate was observed with strain ES04/PCK+PYC, which had inactivated ethanol, lactate, acetate, and 2,3-butanediol pathways and coexpressed PCK and Corynebacterium glutamicum pyruvate carboxylase (PYC). This strain produced succinate from glucose with over 70% yield (gram per gram) without any measurable formation of ethanol, lactate, or 2,3-butanediol under weakly acidic conditions. The impact of lowering the pH from 7.0 to 5.5 on succinate production in this strain was evaluated under pH-controlled batch culture conditions and showed that the lower pH decreased the succinate titer but increased its yield. These findings can be applied to identify additional engineering targets to increase succinate production. PMID:25416770

  4. Therapeutic ketosis with ketone ester delays central nervous system oxygen toxicity seizures in rats.

    Science.gov (United States)

    D'Agostino, Dominic P; Pilla, Raffaele; Held, Heather E; Landon, Carol S; Puchowicz, Michelle; Brunengraber, Henri; Ari, Csilla; Arnold, Patrick; Dean, Jay B

    2013-05-15

    Central nervous system oxygen toxicity (CNS-OT) seizures occur with little or no warning, and no effective mitigation strategy has been identified. Ketogenic diets (KD) elevate blood ketones and have successfully treated drug-resistant epilepsy. We hypothesized that a ketone ester given orally as R,S-1,3-butanediol acetoacetate diester (BD-AcAc(2)) would delay CNS-OT seizures in rats breathing hyperbaric oxygen (HBO(2)). Adult male rats (n = 60) were implanted with radiotelemetry units to measure electroencephalogram (EEG). One week postsurgery, rats were administered a single oral dose of BD-AcAc(2), 1,3-butanediol (BD), or water 30 min before being placed into a hyperbaric chamber and pressurized to 5 atmospheres absolute (ATA) O2. Latency to seizure (LS) was measured from the time maximum pressure was reached until the onset of increased EEG activity and tonic-clonic contractions. Blood was drawn at room pressure from an arterial catheter in an additional 18 animals that were administered the same compounds, and levels of glucose, pH, Po(2), Pco(2), β-hydroxybutyrate (BHB), acetoacetate (AcAc), and acetone were analyzed. BD-AcAc(2) caused a rapid (30 min) and sustained (>4 h) elevation of BHB (>3 mM) and AcAc (>3 mM), which exceeded values reported with a KD or starvation. BD-AcAc(2) increased LS by 574 ± 116% compared with control (water) and was due to the effect of AcAc and acetone but not BHB. BD produced ketosis in rats by elevating BHB (>5 mM), but AcAc and acetone remained low or undetectable. BD did not increase LS. In conclusion, acute oral administration of BD-AcAc(2) produced sustained ketosis and significantly delayed CNS-OT seizures by elevating AcAc and acetone.

  5. Conservation and diversity of seed associated endophytes in Zea across boundaries of evolution, ethnography and ecology.

    Directory of Open Access Journals (Sweden)

    David Johnston-Monje

    Full Text Available Endophytes are non-pathogenic microbes living inside plants. We asked whether endophytic species were conserved in the agriculturally important plant genus Zea as it became domesticated from its wild ancestors (teosinte to modern maize (corn and moved from Mexico to Canada. Kernels from populations of four different teosintes and 10 different maize varieties were screened for endophytic bacteria by culturing, cloning and DNA fingerprinting using terminal restriction fragment length polymorphism (TRFLP of 16S rDNA. Principle component analysis of TRFLP data showed that seed endophyte community composition varied in relation to plant host phylogeny. However, there was a core microbiota of endophytes that was conserved in Zea seeds across boundaries of evolution, ethnography and ecology. The majority of seed endophytes in the wild ancestor persist today in domesticated maize, though ancient selection against the hard fruitcase surrounding seeds may have altered the abundance of endophytes. Four TRFLP signals including two predicted to represent Clostridium and Paenibacillus species were conserved across all Zea genotypes, while culturing showed that Enterobacter, Methylobacteria, Pantoea and Pseudomonas species were widespread, with γ-proteobacteria being the prevalent class. Twenty-six different genera were cultured, and these were evaluated for their ability to stimulate plant growth, grow on nitrogen-free media, solubilize phosphate, sequester iron, secrete RNAse, antagonize pathogens, catabolize the precursor of ethylene, produce auxin and acetoin/butanediol. Of these traits, phosphate solubilization and production of acetoin/butanediol were the most commonly observed. An isolate from the giant Mexican landrace Mixteco, with 100% identity to Burkholderia phytofirmans, significantly promoted shoot potato biomass. GFP tagging and maize stem injection confirmed that several seed endophytes could spread systemically through the plant. One seed

  6. Carbonate phosphonium salts as catalysts for the transesterification of dialkyl carbonates with diols. The competition between cyclic carbonates and linear dicarbonate products.

    Science.gov (United States)

    Selva, Maurizio; Caretto, Alessio; Noè, Marco; Perosa, Alvise

    2014-06-28

    At 90-120 °C, in the presence of methylcarbonate and bicarbonate methyltrioctylphosphonium salts as catalysts ([P8881][A]; [A] = MeOCO2 and HOCO2), the transesterification of non-toxic dimethyl- and diethyl-carbonate (DMC and DEC, respectively) with 1,X-diols (2 ≤ X ≤ 6) proceeds towards the formation of cyclic and linear products. In particular, 1,2-propanediol and ethylene glycol afford propylene- and ethylene-carbonate with selectivity and yields up to 95 and 90%, respectively; while, the reaction of DMC with higher diols such 1,3-butanediol, 2-methyl-1,3-propanediol, 1,3-propanediol, 2,2-dimethyl, 1,3-propanediol, 1,4-butanediol and 1,6-hexanediol produce linear C8-C10 dicarbonates of general formula MeOC(O)O∼∼∼OC(O)OMe as the almost exclusive products. Of note, these dicarbonate derivatives are not otherwise accessible in good yields by other conventional base catalyzed methods. Among 1,3-diols, the only exception was 2-methyl 2,4-pentandiol that yields the corresponding cyclic carbonate, i.e. 4,4,6-trimethyl-1,3-dioxan-2-one. In no one case, polycarbonates are observed. Such remarkable differences of product distributions are ascribed to the structure (branching and relative position of OH groups) of diols and to the role of cooperative (nucleophilic and electrophilic) catalysis which has been proved for onium salts. The investigated carbonate salts are not only effective in amounts as low as 0.5 mol%, but they are highly stable and recyclable.

  7. Characterization of a Zinc-Containing Alcohol Dehydrogenase with Stereoselectivity from the Hyperthermophilic Archaeon Thermococcus guaymasensis▿

    Science.gov (United States)

    Ying, Xiangxian; Ma, Kesen

    2011-01-01

    An alcohol dehydrogenase (ADH) from hyperthermophilic archaeon Thermococcus guaymasensis was purified to homogeneity and was found to be a homotetramer with a subunit size of 40 ± 1 kDa. The gene encoding the enzyme was cloned and sequenced; this gene had 1,095 bp, corresponding to 365 amino acids, and showed high sequence homology to zinc-containing ADHs and l-threonine dehydrogenases with binding motifs of catalytic zinc and NADP+. Metal analyses revealed that this NADP+-dependent enzyme contained 0.9 ± 0.03 g-atoms of zinc per subunit. It was a primary-secondary ADH and exhibited a substrate preference for secondary alcohols and corresponding ketones. Particularly, the enzyme with unusual stereoselectivity catalyzed an anti-Prelog reduction of racemic (R/S)-acetoin to (2R,3R)-2,3-butanediol and meso-2,3-butanediol. The optimal pH values for the oxidation and formation of alcohols were 10.5 and 7.5, respectively. Besides being hyperthermostable, the enzyme activity increased as the temperature was elevated up to 95°C. The enzyme was active in the presence of methanol up to 40% (vol/vol) in the assay mixture. The reduction of ketones underwent high efficiency by coupling with excess isopropanol to regenerate NADPH. The kinetic parameters of the enzyme showed that the apparent Km values and catalytic efficiency for NADPH were 40 times lower and 5 times higher than those for NADP+, respectively. The physiological roles of the enzyme were proposed to be in the formation of alcohols such as ethanol or acetoin concomitant to the NADPH oxidation. PMID:21515780

  8. Role of a Highly Conserved and Catalytically Important Glutamate-49 in the Enterococcus faecalis Acetolactate Synthase

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Miyoung; Lee, Sangchoon; Cho, Junehaeng; Ryu, Seong Eon; Yoon, Moonyoung [Hanyang Univ., Seoul (Korea, Republic of); Koo, Bonsung [Rural Development Administration, Suwon (Korea, Republic of)

    2013-02-15

    Acetolactate synthase (ALS) is a thiamine diphosphate (ThDP)-dependent enzyme that catalyzes the decarboxylation of pyruvate and then condenses the hydroxyethyl moiety with another molecule of pyruvate to give 2-acetolactate (AL). AL is a key metabolic intermediate in various metabolic pathways of microorganisms. In addition, AL can be converted to acetoin, an important physiological metabolite that is excreted by many microorganisms. There are two types of ALSs reported in the literature, anabolic aceto-hydroxyacid synthase (AHAS) and catabolic ALSs (cALS). The anabolic AHAS is primarily found in plants, fungi, and bacteria, is involved in the biosynthesis of branched-chain amino acids (BCAAs), and contains flavin adenine dinucleotide (FAD), whereas the cALS is found only in some bacteria and is involved in the butanediol fermentation pathway. Both of the enzymes are ThDP-dependent and require a divalent metal ion for catalytic activity. Despite the similarities of the reactions catalyzed, the cALS can be distinguished from anabolic AHAS by a low optimal pH of about 6.0, FAD-independent functionality, a genetic location within the butanediol operon, and lack of a regulatory subunit. It is noteworthy that the structural and functional features of AHAS have been extensively studied, in contrast to those of cALS, for which only limited information is available. To date, the only crystal structure of cALS reported is from Klebsiella pneumonia, which revealed that the overall structure of K. pneumonia ALS is similar to that of AHAS except for the FAD binding region found in AHAS.

  9. Conservation and diversity of seed associated endophytes in Zea across boundaries of evolution, ethnography and ecology.

    Science.gov (United States)

    Johnston-Monje, David; Raizada, Manish N

    2011-01-01

    Endophytes are non-pathogenic microbes living inside plants. We asked whether endophytic species were conserved in the agriculturally important plant genus Zea as it became domesticated from its wild ancestors (teosinte) to modern maize (corn) and moved from Mexico to Canada. Kernels from populations of four different teosintes and 10 different maize varieties were screened for endophytic bacteria by culturing, cloning and DNA fingerprinting using terminal restriction fragment length polymorphism (TRFLP) of 16S rDNA. Principle component analysis of TRFLP data showed that seed endophyte community composition varied in relation to plant host phylogeny. However, there was a core microbiota of endophytes that was conserved in Zea seeds across boundaries of evolution, ethnography and ecology. The majority of seed endophytes in the wild ancestor persist today in domesticated maize, though ancient selection against the hard fruitcase surrounding seeds may have altered the abundance of endophytes. Four TRFLP signals including two predicted to represent Clostridium and Paenibacillus species were conserved across all Zea genotypes, while culturing showed that Enterobacter, Methylobacteria, Pantoea and Pseudomonas species were widespread, with γ-proteobacteria being the prevalent class. Twenty-six different genera were cultured, and these were evaluated for their ability to stimulate plant growth, grow on nitrogen-free media, solubilize phosphate, sequester iron, secrete RNAse, antagonize pathogens, catabolize the precursor of ethylene, produce auxin and acetoin/butanediol. Of these traits, phosphate solubilization and production of acetoin/butanediol were the most commonly observed. An isolate from the giant Mexican landrace Mixteco, with 100% identity to Burkholderia phytofirmans, significantly promoted shoot potato biomass. GFP tagging and maize stem injection confirmed that several seed endophytes could spread systemically through the plant. One seed isolate

  10. Genome Sequence of the Plant Growth Promoting Endophytic Bacterium Enterobacter sp. 638

    Energy Technology Data Exchange (ETDEWEB)

    Taghavi, S.; van der Lelie, D.; Hoffman, A.; Zhang, Y.-B.; Walla, M. D.; Vangronsveld, J.; Newman, L.; Monchy, S.

    2010-05-13

    Enterobacter sp. 638 is an endophytic plant growth promoting gamma-proteobacterium that was isolated from the stem of poplar (Populus trichocarpa x deltoides cv. H11-11), a potentially important biofuel feed stock plant. The Enterobacter sp. 638 genome sequence reveals the presence of a 4,518,712 bp chromosome and a 157,749 bp plasmid (pENT638-1). Genome annotation and comparative genomics allowed the identification of an extended set of genes specific to the plant niche adaptation of this bacterium. This includes genes that code for putative proteins involved in survival in the rhizosphere (to cope with oxidative stress or uptake of nutrients released by plant roots), root adhesion (pili, adhesion, hemagglutinin, cellulose biosynthesis), colonization/establishment inside the plant (chemiotaxis, flagella, cellobiose phosphorylase), plant protection against fungal and bacterial infections (siderophore production and synthesis of the antimicrobial compounds 4-hydroxybenzoate and 2-phenylethanol), and improved poplar growth and development through the production of the phytohormones indole acetic acid, acetoin, and 2,3-butanediol. Metabolite analysis confirmed by quantitative RT-PCR showed that, the production of acetoin and 2,3-butanediol is induced by the presence of sucrose in the growth medium. Interestingly, both the genetic determinants required for sucrose metabolism and the synthesis of acetoin and 2,3-butanediol are clustered on a genomic island. These findings point to a close interaction between Enterobacter sp. 638 and its poplar host, where the availability of sucrose, a major plant sugar, affects the synthesis of plant growth promoting phytohormones by the endophytic bacterium. The availability of the genome sequence, combined with metabolome and transcriptome analysis, will provide a better understanding of the synergistic interactions between poplar and its growth promoting endophyte Enterobacter sp. 638. This information can be further exploited to

  11. Production of Chemical Derivatives from Renewables

    Energy Technology Data Exchange (ETDEWEB)

    Davison, Brian; Nghiem, John; Donnelly, Mark; Tsai, Shih-Perng; Frye, John; Landucci, Ron; Griffin, Michael

    1996-06-01

    The purpose of this Cooperative Research and Development Agreement (CRADA) between Lockheed Martin Energy Research Corp., (LMER), Argonne National Laboratory (ANL), National Renewable Energy Laboratory (NREL), and Battelle Memorial Institute, operator of Pacific Northwest National Laboratory (PNNL), (collectively referred to as the 'Contractor'), and Applied Carbochemicals, Inc. (Participant) was to scale-up from bench results an economically promising and competitive process for the production of chemical derivatives from biologically produced succinic acid. The products that were under consideration for production from the succinic acid platform included 1,4-butanediol, {gamma}y-butyrolactone, 2-pyrrolidinone and N-methyl pyrrolidinone. Preliminary economic analyses indicated that this platform was competitive with the most recent petrochemical routes. The Contractors and participant are hereinafter jointly referred to as the 'Parties.' Research to date in succinic acid fermentation, separation and genetic engineering resulted in a potentially economical process based on the use of an Escherichia coli strain AFP111 with suitable characteristics for the production of succinic acid from glucose. Economic analysis has shown that higher value commodity chemicals can be economically produced from succinic acid based on preliminary laboratory findings and predicted catalytic parameters. At the time, the current need was to provide the necessary laboratory follow-up information to properly optimize, design and operate a pilot scale process. The purpose of the pilot work was to validate the integrated process, assure 'robustness' of the process, define operating conditions, and provide samples for potential customer evaluation. The data from the pilot scale process was used in design and development of a full scale production facility. A new strain, AFP111 (patented), discovered at ANL was tested and developed for process use at the Oak

  12. Oxovanadium alkoxides: Structure, reactivity, and sup 51 V NMR characteristics. Crystal and molecular structures of VO(OCH sub 2 CH sub 2 Cl) sub 3 and VOCl sub 2 (THF) sub 2 H sub 2 O

    Energy Technology Data Exchange (ETDEWEB)

    Priebsch, W.; Rehder, D. (Universitaet Hamburg (West Germany))

    1990-08-08

    The vanadyl esters VO(OR){sub 3} (R = Me, Et, Pr, iPr, sBu, tBu, CH{sub 2}CH{sub 2}F, CH{sub 2}CH{sub 2}Cl, CH{sub 2}CCl{sub 3}) have been prepared and their association properties in pentane investigated by {sup 51}V NMR. Limiting (low concentration) {delta}({sup 51}V) values depend on the bulk of R (highest {sup 51}V shielding for tBu). Shielding decreases with increasing concentration (more pronounced for small R groups), owing to the formation of oligomers, probably connected by {mu}-OR groups. The X-ray diffraction study of VO(OCH{sub 2}CH{sub 2}Cl){sub 3} reveals dimer association of molecules belonging to adjacent unit cells via long V-OR bonds (226.1 (2) pm), and a trigonal-bipyramidal geometry for each monomeric unit. From the reaction between VOCl{sub 3} and diols (glycol, 1,3-propanediol, 1,2-, 2,3-, 1,3-, and 1,4-butanediol), complexes are obtained that contain the {l brace}VOCl(OR){sub 2}{r brace} and {l brace}VOCl{sub 2}OR{r brace} moieties and the alcohol coordinated in the monofunctional or bifunctional (chelating and bridging) mode. The {sup 51}V NMR spectrum of VOCl{sub 2}OCH(Me)CH(Me)OH exhibits resolved {sup 51}V-{sup 35,37}Cl coupling: J({sup 51}V-{sup 35}Cl) = 100 Hz; J({sup 51}V-{sup 37}Cl) = 83 Hz. V{sup V}OCl{sub 2}(OCH{sub 2}CH{sub 2}CH{sub 2}OH) reacts with 1,4-butanediol to form V{sup IV}OCl{sub 2}(THF){sub 2}(OH{sub 2}). In the presence of COCL{sub 3}, THF undergoes ether splitting, chlorination, and coordination to vanadium to yield VOCl{sub 2}(OCH{sub 2}CH{sub 2}CH{sub 2}CH{sub 2}Cl). 35 refs., 7 figs., 7 tabs.

  13. Water-enhanced solvation of organics

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jane H. [Univ. of California, Berkeley, CA (United States)

    1993-07-01

    Water-enhanced solvation (WES) was explored for Lewis acid solutes in Lewis base organic solvents, to develop cheap extract regeneration processes. WES for solid solutes was determined from ratios of solubilities of solutes in water-sat. and low-water solvent; both were determined from solid-liquid equilibrium. Vapor-headspace analysis was used to determine solute activity coefficients as function of organic phase water concentration. WES magnitudes of volatile solutes were normalized, set equal to slope of log γs vs xw/xs curve. From graph shape Δ(log γs) represents relative change in solute activity coefficient. Solutes investigated by vapor-headspace analysis were acetic acid, propionic acid, ethanol, 1,2-propylene glycol, 2,3-butylene glycol. Monocarboxylic acids had largest decrease in activity coefficient with water addition followed by glycols and alcohols. Propionic acid in cyclohexanone showed greatest water-enhancement Δ(log γacid)/Δ(xw/xacid) = -0.25. In methylcyclohexanone, the decrease of the activity coefficient of propionic acid was -0.19. Activity coefficient of propionic acid in methylcyclohexanone stopped decreasing once the water reached a 2:1 water to acid mole ratio, implying a stoichiometric relation between water, ketone, and acid. Except for 2,3-butanediol, activity coefficients of the solutes studied decreased monotonically with water content. Activity coefficient curves of ethanol, 1,2-propanediol and 2,3-butanediol did not level off at large water/solute mole ratio. Solutes investigated by solid-liquid equilibrium were citric acid, gallic acid, phenol, xylenols, 2-naphthol. Saturation concentration of citric acid in anhydrous butyl acetate increased from 0.0009 to 0.087 mol/L after 1.3 % (g/g) water co-dissolved into organic phase. Effect of water-enhanced solvation for citric acid is very large but very small for phenol and its derivatives.

  14. Homolactic fermentation from glucose and cellobiose using Bacillus subtilis.

    Science.gov (United States)

    Romero-Garcia, Susana; Hernández-Bustos, Claudia; Merino, Enrique; Gosset, Guillermo; Martinez, Alfredo

    2009-04-21

    BACKGROUNG: Biodegradable plastics can be made from polylactate, which is a polymer made from lactic acid. This compound can be produced from renewable resources as substrates using microorganisms. Bacillus subtilis is a Gram-positive bacterium recognized as a GRAS microorganism (generally regarded as safe) by the FDA. B. subtilis produces and secretes different kind of enzymes, such as proteases, cellulases, xylanases and amylases to utilize carbon sources more complex than the monosaccharides present in the environment. Thus, B. subtilis could be potentially used to hydrolyze carbohydrate polymers contained in lignocellulosic biomass to produce chemical commodities. Enzymatic hydrolysis of the cellulosic fraction of agroindustrial wastes produces cellobiose and a lower amount of glucose. Under aerobic conditions, B. subtilis grows using cellobiose as substrate. In this study, we proved that under non-aerated conditions, B. subtilis ferments cellobiose to produce L-lactate with 82% of the theoretical yield, and with a specific rate of L-lactate production similar to that one obtained fermenting glucose. Under fermentative conditions in a complex media supplemented with glucose, B. subtilis produces L-lactate and a low amount of 2,3-butanediol. To increase the L-lactate production of this organism, we generated the B subtilis CH1 alsS- strain that lacks the ability to synthesize 2,3-butanediol. Inactivation of this pathway, that competed for pyruvate availability, let a 15% increase in L-lactate yield from glucose compared with the parental strain. CH1 alsS- fermented 5 and 10% of glucose to completion in mineral medium supplemented with yeast extract in four and nine days, respectively. CH1 alsS- produced 105 g/L of L-lactate in this last medium supplemented with 10% of glucose. The L-lactate yield was up to 95% using mineral media, and the optical purity of L-lactate was of 99.5% since B. subtilis has only one gene (lctE) that exclusively encodes a L

  15. Quorum Sensing Coordinates Cooperative Expression of Pyruvate Metabolism Genes To Maintain a Sustainable Environment for Population Stability.

    Science.gov (United States)

    Hawver, Lisa A; Giulietti, Jennifer M; Baleja, James D; Ng, Wai-Leung

    2016-12-06

    Quorum sensing (QS) is a microbial cell-cell communication system that regulates gene expression in response to population density to coordinate collective behaviors. Yet, the role of QS in resolving the stresses caused by the accumulation of toxic metabolic by-products at high cell density is not well defined. In response to cell density, QS could be involved in reprogramming of the metabolic network to maintain population stability. Using unbiased metabolomics, we discovered that Vibrio cholerae mutants genetically locked in a low cell density (LCD) QS state are unable to alter the pyruvate flux to convert fermentable carbon sources into neutral acetoin and 2,3-butanediol molecules to offset organic acid production. As a consequence, LCD-locked QS mutants rapidly lose viability when grown with fermentable carbon sources. This key metabolic switch relies on the QS-regulated small RNAs Qrr1-4 but is independent of known QS regulators AphA and HapR. Qrr1-4 dictate pyruvate flux by translational repression of the enzyme AlsS, which carries out the first step in acetoin and 2,3-butanediol biosynthesis. Consistent with the idea that QS facilitates the expression of a common trait in the population, AlsS needs to be expressed cooperatively in a group of cells. Heterogeneous populations with high percentages of cells not expressing AlsS are unstable. All of the cells, regardless of their respective QS states, succumb to stresses caused by toxic by-product accumulation. Our results indicate that the ability of the bacteria to cooperatively control metabolic flux through QS is critical in maintaining a sustainable environment and overall population stability. Our work reveals a novel role for Vibrio cholerae quorum sensing (QS) in relieving the stresses caused by toxic metabolite accumulation when the population becomes crowded through metabolic reprogramming. QS enables V. cholerae switching from a low cell density energy-generating metabolism that is beneficial to

  16. Contribution of liver alcohol dehydrogenase to metabolism of alcohols in rats.

    Science.gov (United States)

    Plapp, Bryce V; Leidal, Kevin G; Murch, Bruce P; Green, David W

    2015-06-05

    The kinetics of oxidation of various alcohols by purified rat liver alcohol dehydrogenase (ADH) were compared with the kinetics of elimination of the alcohols in rats in order to investigate the roles of ADH and other factors that contribute to the rates of metabolism of alcohols. Primary alcohols (ethanol, 1-propanol, 1-butanol, 2-methyl-1-propanol, 3-methyl-1-butanol) and diols (1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol) were eliminated in rats with zero-order kinetics at doses of 5-20 mmol/kg. Ethanol was eliminated most rapidly, at 7.9 mmol/kgh. Secondary alcohols (2-propanol-d7, 2-propanol, 2-butanol, 3-pentanol, cyclopentanol, cyclohexanol) were eliminated with first order kinetics at doses of 5-10 mmol/kg, and the corresponding ketones were formed and slowly eliminated with zero or first order kinetics. The rates of elimination of various alcohols were inhibited on average 73% (55% for 2-propanol to 90% for ethanol) by 1 mmol/kg of 4-methylpyrazole, a good inhibitor of ADH, indicating a major role for ADH in the metabolism of the alcohols. The Michaelis kinetic constants from in vitro studies (pH 7.3, 37 °C) with isolated rat liver enzyme were used to calculate the expected relative rates of metabolism in rats. The rates of elimination generally increased with increased activity of ADH, but a maximum rate of 6±1 mmol/kg h was observed for the best substrates, suggesting that ADH activity is not solely rate-limiting. Because secondary alcohols only require one NAD(+) for the conversion to ketones whereas primary alcohols require two equivalents of NAD(+) for oxidation to the carboxylic acids, it appears that the rate of oxidation of NADH to NAD(+) is not a major limiting factor for metabolism of these alcohols, but the rate-limiting factors are yet to be identified. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  17. Homolactic fermentation from glucose and cellobiose using Bacillus subtilis

    Directory of Open Access Journals (Sweden)

    Martinez Alfredo

    2009-04-01

    Full Text Available Abstract Backgroung Biodegradable plastics can be made from polylactate, which is a polymer made from lactic acid. This compound can be produced from renewable resources as substrates using microorganisms. Bacillus subtilis is a Gram-positive bacterium recognized as a GRAS microorganism (generally regarded as safe by the FDA. B. subtilis produces and secretes different kind of enzymes, such as proteases, cellulases, xylanases and amylases to utilize carbon sources more complex than the monosaccharides present in the environment. Thus, B. subtilis could be potentially used to hydrolyze carbohydrate polymers contained in lignocellulosic biomass to produce chemical commodities. Enzymatic hydrolysis of the cellulosic fraction of agroindustrial wastes produces cellobiose and a lower amount of glucose. Under aerobic conditions, B. subtilis grows using cellobiose as substrate. Results In this study, we proved that under non-aerated conditions, B. subtilis ferments cellobiose to produce L-lactate with 82% of the theoretical yield, and with a specific rate of L-lactate production similar to that one obtained fermenting glucose. Under fermentative conditions in a complex media supplemented with glucose, B. subtilis produces L-lactate and a low amount of 2,3-butanediol. To increase the L-lactate production of this organism, we generated the B subtilis CH1 alsS- strain that lacks the ability to synthesize 2,3-butanediol. Inactivation of this pathway, that competed for pyruvate availability, let a 15% increase in L-lactate yield from glucose compared with the parental strain. CH1 alsS- fermented 5 and 10% of glucose to completion in mineral medium supplemented with yeast extract in four and nine days, respectively. CH1 alsS- produced 105 g/L of L-lactate in this last medium supplemented with 10% of glucose. The L-lactate yield was up to 95% using mineral media, and the optical purity of L-lactate was of 99.5% since B. subtilis has only one gene (lctE that

  18. Polyurethane/fluor-hydroxyapatite nanocomposite scaffolds for bone tissue engineering. Part I: morphological, physical, and mechanical characterization

    Science.gov (United States)

    Asefnejad, Azadeh; Behnamghader, Aliasghar; Khorasani, Mohammad Taghi; Farsadzadeh, Babak

    2011-01-01

    In this study, new nano-fluor-hydroxyapatite (nFHA)/polyurethane composite scaffolds were fabricated for potential use in bone tissue engineering. Polyester urethane samples were synthesized from polycaprolactone, hexamethylene diisocyanate, and 1,4-butanediol as chain extender. Nano fluor-hydroxyapatite (nFHA) was successfully synthesized by sol-gel method. The solid–liquid phase separation and solvent sublimation methods were used for preparation of the porous composites. Mechanical properties, chemical structure, and morphological characteristics of the samples were investigated by compressive test, Fourier transform infrared, and scanning electron microscopy (SEM) techniques, respectively. The effect of nFHA powder content on porosity and pore morphology was investigated. SEM images demonstrated that the scaffolds were constituted of interconnected and homogeneously distributed pores. The pore size of the scaffolds was in the range 50–250 μm. The result obtained in this research revealed that the porosity and pore average size decreased and compressive modulus increased with nFHA percentage. Considering morphological, physical, and mechanical properties, the scaffold with a higher ratio of nFHA has suitable potential use in tissue regeneration. PMID:21289986

  19. Melt electrospinning of biodegradable polyurethane scaffolds

    Science.gov (United States)

    Karchin, Ari; Simonovsky, Felix I.; Ratner, Buddy D.; Sanders, Joan E.

    2014-01-01

    Electrospinning from the melt, in contrast to from solution, is an attractive tissue engineering scaffold manufacturing process as it allows for the formation of small diameter fibers while eliminating potentially cytotoxic solvents. Despite this, there is a dearth of literature on scaffold formation via melt electrospinning. This is likely due to the technical challenges related to the need for a well-controlled high temperature setup and the difficulty in developing an appropriate polymer. In this paper, a biodegradable and thermally stable polyurethane (PU) is described specifically for use in melt electrospinning. Polymer formulations of aliphatic PUs based on (CH2)4-content diisocyanates, polycaprolactone (PCL), 1,4-butanediamine and 1,4-butanediol (BD) were evaluated for utility in the melt electrospinning process. The final polymer formulation, a catalyst-purified PU based on 1,4-butane diisocyanate, PCL and BD in a 4/1/3 molar ratio with a weight-average molecular weight of about 40 kDa, yielded a nontoxic polymer that could be readily electrospun from the melt. Scaffolds electrospun from this polymer contained point bonds between fibers and mechanical properties analogous to many in vivo soft tissues. PMID:21640853

  20. Manufacturing of biodegradable polyurethane scaffolds based on polycaprolactone using a phase separation method: physical properties and in vitro assay

    Science.gov (United States)

    Asefnejad, Azadeh; Khorasani, Mohammad Taghi; Behnamghader, Aliasghar; Farsadzadeh, Babak; Bonakdar, Shahin

    2011-01-01

    Background Biodegradable polyurethanes have found widespread use in soft tissue engineering due to their suitable mechanical properties and biocompatibility. Methods In this study, polyurethane samples were synthesized from polycaprolactone, hexamethylene diisocyanate, and a copolymer of 1,4-butanediol as a chain extender. Polyurethane scaffolds were fabricated by a combination of liquid–liquid phase separation and salt leaching techniques. The effect of the NCO:OH ratio on porosity content and pore morphology was investigated. Results Scanning electron micrographs demonstrated that the scaffolds had a regular distribution of interconnected pores, with pore diameters of 50–300 μm, and porosities of 64%–83%. It was observed that, by increasing the NCO:OH ratio, the average pore size, compressive strength, and compressive modulus increased. L929 fibroblast and chondrocytes were cultured on the scaffolds, and all samples exhibited suitable cell attachment and growth, with a high level of biocompatibility. Conclusion These biodegradable polyurethane scaffolds demonstrate potential for soft tissue engineering applications. PMID:22072874

  1. Novel non-cytotoxic, bioactive and biodegradable hybrid materials based on polyurethanes/TiO2 for biomedical applications.

    Science.gov (United States)

    González-García, Dulce M; Téllez Jurado, L; Jiménez-Gallegos, R; Rodríguez-Lorenzo, Luis M

    2017-06-01

    Titanium compounds have demonstrated great interfacial properties with biological tissues whereas a wide variety of polyurethanes have also been successfully probed in medical applications. However, studies about hybrids based on polyurethanes/TiO2 for medical applications are scarce. The aim of this work is to design novel biodegradable hybrid materials based on polyurethanes/TiO2 (80% organic-20% inorganic) and to perform a preliminary study of the potential applications in bone regeneration. The hybrids have been prepared by a sol-gel reaction using titanium isopropoxide as precursor of the inorganic component and polyurethane as the organic one. A series of polyurethanes has been prepared using different polyesters glycol succinate as soft segment, and 1,6-diisocyanatohexane (HDI) and butanediol (BD) as linear hard segment. The spectroscopy techniques used allow to confirm the formation of the required polyurethanes by the identification of bands related to carboxylic groups (COOH), and the amine groups (NH), and also the TiOH bonds and the bonds related to the interconnected network between the inorganic and the organic components from hybrids. The results from SEM/EDS show a homogeneous distribution of the inorganic component into the organic matrix. The nontoxic character of the hybrid (H400) was probed using MG-63 cell line with over 90% of cell viability. Finally, the formation of a hydroxyapatite layer in the material surface after 21days of soaking in SBF shows the bioactive character. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Effects of vitrification medium composition on the survival of bovine in vitro produced embryos, following in straw-dilution, in vitro and in vivo following transfer.

    Science.gov (United States)

    Pugh, P A; Tervit, H R; Niemann, H

    2000-02-28

    This study examined the effects of adding a macromolecule, polyvinylpyrrolidone (10% PVP) and a sugar (0.3 M trehalose) to vitrification solutions (VS) containing either one (40% ethylene glycol [EG], two (25% EG+25% DMSO) or three (20% EG+20% DMSO+10% 1, 3-butanediol [BD]) permeable cryoprotectants on the survival and hatching of IVP bovine embryos, following vitrification, warming and in-straw cryoprotectant dilution. Grade 1 and 2 compact morulae and blastocysts were selected on Day 7 (Day 0=IVF) of culture in SOFaaBSA and equilibrated for 10 min at room temperature in 10% EG. Following exposure, for up to 1 min at 4 degrees C, to one of the above VS (with or without PVP+trehalose), the embryos were loaded into straws and immersed in liquid nitrogen. Following warming and in-straw cryoprotectant dilution, the embryos were cultured for 48 h to assess hatching. There was no effect of VS on the survival of embryos after 24 h, however fewer compact morulae than blastocysts survived after 24 h (24% vs. 75%; Pvitrification (fresh vs. vitrified; 1/5 [20%] vs. 3/18 [17]). These data demonstrate that a VS comprising three cryoprotectants, rather than one, enables more embryos to hatch during post-thaw culture and that the survival, following direct transfer of these vitrified embryos, is not different to non-vitrified embryos.

  3. Photoinduced reactivity of liquid ethanol at high pressure.

    Science.gov (United States)

    Ceppatelli, Matteo; Fanetti, Samuele; Citroni, Margherita; Bini, Roberto

    2010-12-02

    The room temperature photoinduced reactivity of liquid ethanol has been studied as a function of pressure up to 1.5 GPa by means of a diamond anvil cell. Exploiting the dissociative character of the lowest electronic excited states, reached through two-photon absorption of near-UV photons (350 nm), irreversible reactive processes have been triggered in the pure system. The active species are radicals forming along two main dissociation channels involving the split of C-O and O-H bonds. The characterization of the reaction products has been performed by in situ FTIR and Raman spectroscopy. At pressures of a few megapascals, molecular hydrogen is the main reaction product, an important issue in the framework of environmentally friendly synthesis of this energetic vector. In the gigapascal range, the main products are ethane, 2-butanol, 2,3-butanediol, 1,1-diethoxyethane, and some carbonylic compounds. The relative amount of these species changes with pressure reflecting the nature of the radicals formed in the photodissociation process. As the pressure increases, the processes requiring a greater molecularity are favored, whereas those requiring internal rearrangements are inhibited. Disproportion products like CH(4), H(2)O, and CO(2) increase when the amount of ethanol decreases due to the reaction, becoming the main products only when ethanol is exhausted.

  4. Shape memory polymers based on uniform aliphatic urethane networks

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, T S; Bearinger, J P; Herberg, J L; Marion III, J E; Wright, W J; Evans, C L; Maitland, D J

    2007-01-19

    Aliphatic urethane polymers have been synthesized and characterized, using monomers with high molecular symmetry, in order to form amorphous networks with very uniform supermolecular structures which can be used as photo-thermally actuable shape memory polymers (SMPs). The monomers used include hexamethylene diisocyanate (HDI), trimethylhexamethylenediamine (TMHDI), N,N,N{prime},N{prime}-tetrakis(hydroxypropyl)ethylenediamine (HPED), triethanolamine (TEA), and 1,3-butanediol (BD). The new polymers were characterized by solvent extraction, NMR, XPS, UV/VIS, DSC, DMTA, and tensile testing. The resulting polymers were found to be single phase amorphous networks with very high gel fraction, excellent optical clarity, and extremely sharp single glass transitions in the range of 34 to 153 C. Thermomechanical testing of these materials confirms their excellent shape memory behavior, high recovery force, and low mechanical hysteresis (especially on multiple cycles), effectively behaving as ideal elastomers above T{sub g}. We believe these materials represent a new and potentially important class of SMPs, and should be especially useful in applications such as biomedical microdevices.

  5. Trimethyl-β-cyclodextrin-encapsulated monolithic capillary columns: Preparation, characterization and chiral nano-LC application.

    Science.gov (United States)

    Ghanem, Ashraf; Adly, Frady G; Sokerik, Yasser; Antwi, Nana Yaa; Shenashen, Mohamed A; El-Safty, Sherif A

    2017-07-01

    Trimethylated-β-cyclodextrin (TM-β-CD) was encapsulated within several polymer monolithic capillary columns for reversed-phase chiral nano-liquid chromatography (nano-LC). The monolithic phases were prepared using the one-pot in situ copolymerization of ethylene glycol dimethacrylate (EDMA), glycidyl methacrylate (GMA) monomers and 1-propanol, 1,4-butanediol as progenic solvents in presence of TM-β-CD solution within fused silica capillaries (150µm I.D.). The obtained chiral monolithic stationery phases were characterized by scanning electron microscopy (SEM), N 2 adsorption/desorption isotherms, wide angle x-ray diffraction (WAXRD), thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The materials characterization demonstrated that monolithic phases with higher concentration of TM-β-CD have relatively larger surface area, smaller pore size and larger total pore volume compared to those with lower concentration TM-β-CD. The prepared columns were tested for their enantioseparation efficiency of a range of racemic pharmaceuticals. The screening results demonstrated the potential of functionalizing polymer monolithic stationary phases with TM-β-CD using the in situ encapsulation approach. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

  6. Preparation and characterization of alkyl methacrylate-based monolithic columns for capillary gas chromatography applications.

    Science.gov (United States)

    Yusuf, Kareem; Aqel, Ahmad; A L Othman, Zeid; Badjah-Hadj-Ahmed, Ahmed Yacine

    2013-08-02

    Gas chromatography (GC) is considered the least common application of both polymer and silica-based monolithic columns. This study describes the fabrication of alkyl methacrylate monolithic materials for use as stationary phases in capillary gas chromatography. Following the deactivation of the capillary surface with 3-(trimethoxysilyl)propyl methacrylate (TMSM), the monoliths were formed by the co-polymerization of either hexyl methacrylate (HMA) or lauryl methacrylate (LMA) with different percentage of ethylene glycol dimethacrylate (EDMA) in presence of an initiator (azobisisobutyronitrile, AIBN) and a mixture of porogens include 1-propanol, 1,4-butanediol and water. The monoliths were prepared in 500mm length capillaries possessing inner diameters of 250μm. The efficiencies of the monolithic columns for low molecular weight compounds significantly improved as the percentage of crosslinker was increased, because of the greater proportion of pores less than 50nm. The columns containing lower percentages of crosslinker were able to rapidly separate a series of 8 alkane members in 0.7min, but the separation was less efficient for the light alkanes. Columns prepared with the lauryl methacrylate monomer yielded a different morphology for the monolith-interconnected channels. The channels were more branched, which increased the separation time, and unlike the other columns, allowed for temperature programming. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Evaluation of glycidyl methacrylate-based monolith functionalized with weak anion exchange moiety inside 0.5 mm i.d. column for liquid chromatographic separation of DNA

    Directory of Open Access Journals (Sweden)

    Aprilia Nur Tasfiyati

    2016-03-01

    Full Text Available In this study, the organic polymer monolith was developed as a weak anion exchanger column in high performance liquid chromatography for DNA separation. Methacrylate-based monolithic column was prepared in microbore silicosteel column (100 × 0.5 mm i.d. by in-situ polymerization reaction using glycidyl methacrylate as monomer; ethylene dimethacrylate as crosslinker; 1-propanol, 1,4-butanediol, and water as porogenic solvents, with the presence of initiator α,α′-azobisisobutyronitrile (AIBN. The monolith matrix was modified with diethylamine to create weak anion exchanger via ring opening reaction of epoxy groups. The morphology of the monolithic column was studied by SEM. The properties of the monolithic column, such as permeability, mechanical stability, binding capacity and pore size distribution, were characterized in detail. From the results of the characterization, monoliths poly-(GMA-co-EDMA with total monomer percentage (%T 40 and crosslinker percentage (%C 25 was found to be the ideal composition of monomer and crosslinker. It has good mechanical stability and high permeability, adequate molecular recognition sites (represented with binding capacity value of 36 mg ml−1, and has relatively equal proportion of flow-through pore and mesopores (37.2% and 41.1% respectively. Poly-(GMA-co-EDMA with %T 40 and %C 25 can successfully separate oligo(dT12–18 and 50 bp DNA ladder with good resolution.

  8. Electro-Fermentation in Aid of Bioenergy and Biopolymers

    Directory of Open Access Journals (Sweden)

    Prasun Kumar

    2018-02-01

    Full Text Available The soaring levels of industrialization and rapid progress towards urbanization across the world have elevated the demand for energy besides generating a massive amount of waste. The latter is responsible for poisoning the ecosystem in an exponential manner, owing to the hazardous and toxic chemicals released by them. In the past few decades, there has been a paradigm shift from “waste to wealth”, keeping the value of high organic content available in the wastes of biological origin. The most practiced processes are that of anaerobic digestion, leading to the production of methane. However; such bioconversion has limited net energy yields. Industrial fermentation targeting value-added bioproducts such as—H2, butanediols; polyhydroxyalkanoates, citric acid, vitamins, enzymes, etc. from biowastes/lignocellulosic substrates have been planned to flourish in a multi-step process or as a “Biorefinery”. Electro-fermentation (EF is one such technology that has attracted much interest due to its ability to boost the microbial metabolism through extracellular electron transfer during fermentation. It has been studied on various acetogens and methanogens, where the enhancement in the biogas yield reached up to 2-fold. EF holds the potential to be used with complex organic materials, leading to the biosynthesis of value-added products at an industrial scale.

  9. Comprehensive genomic analysis of a plant growth-promoting rhizobacterium Pantoea agglomerans strain P5.

    Science.gov (United States)

    Shariati J, Vahid; Malboobi, Mohammad Ali; Tabrizi, Zeinab; Tavakol, Elahe; Owilia, Parviz; Safari, Maryam

    2017-11-15

    In this study, we provide a comparative genomic analysis of Pantoea agglomerans strain P5 and 10 closely related strains based on phylogenetic analyses. A next-generation shotgun strategy was implemented using the Illumina HiSeq 2500 technology followed by core- and pan-genome analysis. The genome of P. agglomerans strain P5 contains an assembly size of 5082485 bp with 55.4% G + C content. P. agglomerans consists of 2981 core and 3159 accessory genes for Coding DNA Sequences (CDSs) based on the pan-genome analysis. Strain P5 can be grouped closely with strains PG734 and 299 R using pan and core genes, respectively. All the predicted and annotated gene sequences were allocated to KEGG pathways. Accordingly,  genes involved in plant growth-promoting (PGP) ability, including phosphate solubilization, IAA and siderophore production, acetoin and 2,3-butanediol synthesis and bacterial secretion, were assigned. This study provides an in-depth view of the PGP characteristics of strain P5, highlighting its potential use in agriculture as a biofertilizer.

  10. Characterization and biocompatibility of epoxy-crosslinked dermal sheep collagens.

    Science.gov (United States)

    van Wachem, P B; Zeeman, R; Dijkstra, P J; Feijen, J; Hendriks, M; Cahalan, P T; van Luyn, M J

    1999-11-01

    Dermal sheep collagen (DSC), which was crosslinked with 1, 4-butanediol diglycidyl ether (BD) by using four different conditions, was characterized and its biocompatibility was evaluated after subcutaneous implantation in rats. Crosslinking at pH 9.0 (BD90) or with successive epoxy and carbodiimide steps (BD45EN) resulted in a large increase in the shrinkage temperature (T(s)) in combination with a clear reduction in amines. Crosslinking at pH 4.5 (BD45) increased the T(s) of the material but hardly reduced the number of amines. Acylation (BD45HAc) showed the largest reduction in amines in combination with the lowest T(s). An evaluation of the implants showed that BD45, BD90, and BD45EN were biocompatible. A high influx of polymorphonuclear cells and macrophages was observed for BD45HAc, but this subsided at day 5. At week 6 the BD45 had completely degraded and BD45HAc was remarkably reduced in size, while BD45EN showed a clear size reduction of the outer DSC bundles; BD90 showed none of these features. This agreed with the observed degree of macrophage accumulation and giant cell formation. None of the materials calcified. For the purpose of soft tissue replacement, BD90 was defined as the material of choice because it combined biocompatibility, low cellular ingrowth, low biodegradation, and the absence of calcification with fibroblast ingrowth and new collagen formation. Copyright 1999 John Wiley & Sons, Inc.

  11. First steps towards tissue engineering of small-diameter blood vessels: preparation of flat scaffolds of collagen and elastin by means of freeze drying.

    Science.gov (United States)

    Buttafoco, L; Engbers-Buijtenhuijs, P; Poot, A A; Dijkstra, P J; Daamen, W F; van Kuppevelt, T H; Vermes, I; Feijen, J

    2006-05-01

    Porous scaffolds composed of collagen or collagen and elastin were prepared by freeze drying at temperatures between -18 and -196 degrees C. All scaffolds had a porosity of 90-98% and a homogeneous distribution of pores. Freeze drying at -18 degrees C afforded collagen and collagen/elastin matrices with average pore sizes of 340 and 130 mum, respectively. After 20 successive cycles up to 10% of strain, collagen/elastin dense films had a total degree of strain recovery of 70% +/- 5%, which was higher than that of collagen films (42% +/- 6%). Crosslinking of collagen/elastin matrices either in water or ethanol/water (40% v/v) was carried out using a carbodiimide (N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride, EDC) in combination with a succinimide (N-hydroxysuccinimide, NHS) in the presence or absence of a diamine (J230) or by reaction with butanediol diglycidylether (BDGE), followed by EDC/NHS. Crosslinking with EDC/NHS or EDC/NHS/J230 resulted in matrices with increased stiffness as compared to noncrosslinked matrices, whereas sequential crosslinking with the diglycidylether and EDC/NHS yielded very brittle scaffolds. Ethanol/water was the preferred solvent in the crosslinking process because of its ability to preserve the open porous structure during crosslinking. Smooth muscle cells were seeded on the (crosslinked) scaffolds and could be expanded during 14 days of culturing. (c) 2005 Wiley Periodicals, Inc.

  12. Structural, thermal and surface characterization of thermoplastic polyurethanes based on poly(dimethylsiloxane

    Directory of Open Access Journals (Sweden)

    Pergal Marija V.

    2014-01-01

    Full Text Available In this study, the synthesis, structure and physical properties of two series of thermoplastic polyurethanes based on hydroxypropyl terminated poly(dimethylsiloxane (HP-PDMS or hydroxyethoxy propyl terminated poly(dimethylsiloxane (EO-PDMS as a soft segment, and 4,4’-methylenediphenyl diisocyanate and 1,4-butanediol as a hard segment were investigated. Each series is composed of samples prepared with a different soft segment. The polyurethanes were synthesized by two-step polyaddition in solution. The effects of the type and content of PDMS segments on the structure, thermal and surface properties of copolymers were studied by 1H NMR, 13C NMR and two-dimensional NMR (HMBC and ROESY spectroscopy, GPC, DSC, TGA, WAXS, SEM, water contact angle and water absorption measurements. Thermal properties investigated by DSC indicated that the presence of soft PDMS segments lowers the glass transition and melting temperatures of the hard phase as well as the degree of crystallinity. SEM analysis of copolymers with a lower soft segment content confirmed the presence of spherulite superstructures, which arise from the crystallization of the hard segments. When compared with polyurethanes prepared from HP-PDMS, copolymers synthesized from EO-PDMS with the same content of the soft segments have higher degree of crystallinity, better thermal stability and less hydrophobic surface. Our results show that the synthesized polyurethanes have good thermal and surface properties, which could be further modified by changing the type or content of the soft segments.

  13. Catalysis for biomass and CO2 use through solar energy: opening new scenarios for a sustainable and low-carbon chemical production.

    Science.gov (United States)

    Lanzafame, Paola; Centi, Gabriele; Perathoner, Siglinda

    2014-11-21

    The use of biomass, bio-waste and CO2 derived raw materials, the latter synthesized using H2 produced using renewable energy sources, opens new scenarios to develop a sustainable and low carbon chemical production, particularly in regions such as Europe lacking in other resources. This tutorial review discusses first this new scenario with the aim to point out, between the different possible options, those more relevant to enable this new future scenario for the chemical production, commenting in particular the different drivers (economic, technological and strategic, environmental and sustainability and socio-political) which guide the selection. The case of the use of non-fossil fuel based raw materials for the sustainable production of light olefins is discussed in more detail, but the production of other olefins and polyolefins, of drop-in intermediates and other platform molecules are also analysed. The final part discusses the role of catalysis in establishing this new scenario, summarizing the development of catalysts with respect to industrial targets, for (i) the production of light olefins by catalytic dehydration of ethanol and by CO2 conversion via FTO process, (ii) the catalytic synthesis of butadiene from ethanol, butanol and butanediols, and (iii) the catalytic synthesis of HMF and its conversion to 2,5-FDCA, adipic acid, caprolactam and 1,6-hexanediol.

  14. Volatile compounds as potential defective coffee beans' markers.

    Science.gov (United States)

    Toci, Aline T; Farah, Adriana

    2008-06-01

    Although Brazil is the largest raw coffee producer and exporter in the world, a large amount of its Arabica coffee production is considered inappropriate for exportation. This by-product of coffee industry is called PVA due to the presence of black (P), green (V) and sour (A) defective beans, which are known to contribute considerably for cup quality decrease. Data on the volatile composition of Brazilian defective coffee beans are scarce. In this study, we evaluated the volatile composition of defective coffee beans (two lots) compared to good quality beans from the respective lots. Potential defective beans' markers were identified. In the raw samples, 2-methylpyrazine and 2-furylmethanol acetate were identified only in black-immature beans and butyrolactone only in sour beans, while benzaldehyde and 2,3,5,6-tetramethylpyrazine showed to be potential markers of defective beans in general. In the roasted PVA beans, pyrazine, 2,3-butanediol meso, 2-methyl-5-(1-propenyl)pyrazine, hexanoic acid, 4-ethyl-guayacol and isopropyl p-cresol sulfide also showed to be potential defective coffee beans' markers. Copyright © 2007 Elsevier Ltd. All rights reserved.

  15. Volatile fingerprint of Brazilian defective coffee seeds: corroboration of potential marker compounds and identification of new low quality indicators.

    Science.gov (United States)

    Toci, Aline T; Farah, Adriana

    2014-06-15

    In the present work, the volatile profiles of green and roasted Brazilian defective coffee seeds and their controls were characterised, totalling 159 compounds. Overall, defective seeds showed higher number and concentration of volatile compounds compared to those of control seeds, especially pyrazines, pyrroles and phenols. Corroborating our previous results, butyrolactone and hexanoic acid, previously considered as potential defective seeds' markers, were observed only in raw and roasted defective seeds, respectively, and not in control seeds. New compounds were suggested as potential defective seeds' markers: hexanoic acid (for raw and roasted defective seeds in general), butyrolactone (for raw defective seeds in general), and 3-ethyl-2-methyl-1,3-hexadiene (for raw black seeds); β-linalool and 2-butyl-3,5-dimethylpyrazine (for roasted defective seeds in general), and 2-pentylfuran (for roasted black seeds). Additional compounds suggested as low quality indicators were 2,3,5,6-tetramethylpyrazine,2,3-butanediol and 4-ethylguaiacol, β-linalool, 2-,3-dimethylbutyl butanoate, 2-phenylethyl acetate, 2,3-butanedione, hexanedioic acid, guaiacol, 2,3-dihydro-2-methyl-1H-benzopyrrol, 3-methylpiperidine, 2-pentylpiperidine, 3-octen-2-one, 2-octenal, 2-pentylfuran and 2-butyl-3-methylpyrazine. Copyright © 2014. Published by Elsevier Ltd.

  16. Microencapsulation of 2-octylcyanoacrylate tissue adhesive for self-healing acrylic bone cement

    Science.gov (United States)

    Brochu, Alice B. W.; Chyan, William J.; Reichert, William M.

    2014-01-01

    Here, we report the first phase of developing self-healing acrylic bone cement: the preparation and characterization of polyurethane (PUR) microcapsules containing a medical cyanoacrylate tissue adhesive. Capsules were prepared by interfacial polymerization of a toluene-2,4-diisocyanate-based polyurethane prepolymer with 1,4-butanediol to encapsulate 2-octylcyanoacrylate (OCA). Various capsule characteristics, including: resultant morphology, average size and size distribution, shell thickness, content and reactivity of encapsulated agent, and shelf life are investigated and their reliance on solvent type and amount, surfactant type and amount, temperature, pH, agitation rate, reaction time, and mode of addition of the oil phase to the aqueous phase are presented. Capsules had average diameters ranging from 74 to 222 μm and average shell thicknesses ranging from 1.5 to 6 μm. The capsule content was determined via thermogravimetric analysis and subsequent analysis of the capsules following up to 8 weeks storage revealed minimal loss of core contents. Mechanical testing of OCA-containing capsules showed individual capsules withstood compressive forces up to a few tenths of Newtons, and the contents released from crushed capsules generated tensile adhesive forces of a few Newtons. Capsules were successfully mixed into the poly(- methyl methacrylate) bone cement, surviving the mixing process, exposure to methyl methacrylate monomer, and the resulting exothermic matrix curing. PMID:22807313

  17. (1)H NMR-based metabolomic approach for understanding the fermentation behaviors of wine yeast strains.

    Science.gov (United States)

    Son, Hong-Seok; Hwang, Geum-Sook; Kim, Ki Myong; Kim, Eun-Young; van den Berg, Frans; Park, Won-Mok; Lee, Cherl-Ho; Hong, Young-Shick

    2009-02-01

    (1)H NMR spectroscopy coupled with multivariate statistical analysis was used for the first time to investigate metabolic changes in musts during alcoholic fermentation and wines during aging. Three Saccharomyces cerevisiae yeast strains (RC-212, KIV-1116, and KUBY-501) were also evaluated for their impacts on the metabolic changes in must and wine. Pattern recognition (PR) methods, including PCA, PLS-DA, and OPLS-DA scores plots, showed clear differences for metabolites among musts or wines for each fermentation stage up to 6 months. Metabolites responsible for the differentiation were identified as valine, 2,3-butanediol (2,3-BD), pyruvate, succinate, proline, citrate, glycerol, malate, tartarate, glucose, N-methylnicotinic acid (NMNA), and polyphenol compounds. PCA scores plots showed continuous movements away from days 1 to 8 in all musts for all yeast strains, indicating continuous and active fermentation. During alcoholic fermentation, the highest levels of 2,3-BD, succinate, and glycerol were found in musts with the KIV-1116 strain, which showed the fastest fermentation or highest fermentative activity of the three strains, whereas the KUBY-501 strain showed the slowest fermentative activity. This study highlights the applicability of NMR-based metabolomics for monitoring wine fermentation and evaluating the fermentative characteristics of yeast strains.

  18. Thermal expansion of vitrified blood vessels permeated with DP6 and synthetic ice modulators.

    Science.gov (United States)

    Eisenberg, David P; Taylor, Michael J; Jimenez-Rios, Jorge L; Rabin, Yoed

    2014-06-01

    This study provides thermal expansion data for blood vessels permeated with the cryoprotective cocktail DP6, when combined with selected synthetic ice modulators (SIMs): 12% polyethylene glycol 400, 6% 1,3-cyclohexanediol, and 6% 2,3-butanediol. The general classification of SIMs includes molecules that modulate ice nucleation and growth, or possess properties of stabilizing the amorphous state, by virtue of their chemical structure and at concentrations that are not explained on a purely colligative basis. The current study is part of an ongoing effort to characterize thermo-mechanical effects on structural integrity of cryopreserved materials, where thermal expansion is the driving mechanism to thermo-mechanical stress. This study focuses on the lower part of the cryogenic temperature range, where the cryoprotective agent (CPA) behaves as a solid for all practical applications. By combining results obtained in the current study with literature data on the thermal expansion in the upper part of the cryogenic temperature range, unified thermal expansion curves are presented. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Recent trends on techno-economic assessment (TEA of sugarcane biorefineries

    Directory of Open Access Journals (Sweden)

    Mohsen Ali Mandegari

    2017-09-01

    Full Text Available Sustainability challenges, e.g., climate change, resource depletion, and expanding populations, have triggered a swift move towards a circular bio-economy which is expected to evolve progressively in the coming decades. However, the transition from a fossil fuel-based economy to a bio-based economy requires the exploitation of scientific innovations and step changes in the infrastructure of chemical industry. Biorefineries have been extensively investigated for biofuel production from first and second generation feedstocks, whereas some research activities have been conducted on production of biochemical and biopolymers from renewable resources. Techno-economic evaluation of diverse technologies for production of biofuels and biochemical is a crucial step for decision making in the development of bio-economy. This contribution focuses on the economic studies carried out on biorefineries converting sugarcane bagasse, due to its availability and importance in the South African context, into value-added products. Recent studies on biofuel production via biochemical pathway, e.g., ethanol, butanol, or thermochemical pathway, e.g., methanol and bio jet fuel as well as production of biochemicals with high market demands and diverse applications such as lactic acid, succinic acid, and xylitol have been briefly reviewed. In addition, an overview on the production of biopolymers such as polyl-lactic acid and bio-based monomers, i.e., butanediol, from sugarcane bagasse is reported.

  20. An epidemic of occupational contact dermatitis from an acrylic glue.

    Science.gov (United States)

    Kiec-Swierczynska, Marta; Krecisz, Beata; Swierczynska-Machura, Dominika; Zaremba, Joanna

    2005-03-01

    Dermatological examinations were performed in 81 workers involved in the manufacture of electric coils for television displays, who had worked for 4 years in contact with a glue containing isobornyl acrylate, acrylic acid, N,N dimethyleneacrylamide, phosphine oxide, bis(2,6-dimethoxybenzoyl) (2,4,4-trimethylpentyl)- and beta-carboxyethyl acrylate. The glue was cured by 350-500-nm ultraviolet and visible radiations. Acrylate-specific dermal lesions were detected in 21 (25.9%) people. Occupational irritant contact dermatitis was diagnosed in 12 (15%) of the workers and occupational allergic contact dermatitis in 9 (11.2%). 12 people reacted to acrylates. Cross-reactions with methacrylates were not observed. The highest number of positive tests was obtained with triethyleneglycol diacrylate (10 people) and diethyleneglycol diacrylate (9), followed by 1,6-hexanediol diacrylate (5), 1,4-butanediol diacrylate (4), beta-carboxyethyl acrylate (3), tripropyleneglycol diacrylate (2) and pentaerythritol triacrylate (2). No cases of allergy to isobornyl acrylate, N,N-methylenebisacrylamide or phosphine oxide were noted.

  1. Occupational allergic contact dermatitis caused by epoxy diacrylate in ultraviolet-light-cured paint, and bisphenol A in dental composite resin.

    Science.gov (United States)

    Jolanki, R; Kanerva, L; Estlander, T

    1995-08-01

    Allergic contact dermatitis (ACD) caused by epoxy di(meth)acrylates or bisphenol A is rare. Here 2 such cases are reported. A dental assistant had allergic contact dermatitis (ACD) caused by bisphenol A contained in dental composite resin (DCR) products based on epoxy dimethacrylate. The contact allergy was verified by allergic patch test reactions to bisphenol A and 2 DCRs. The DCRs giving allergic reactions were analyzed, and 0.014-0.015% of bisphenol A was detected. Occupational ACD caused by bisphenol A in dental composite resins has not been described before. The other patient was a male process worker in a paint factory. He was sensitized by an epoxy diacrylate, 2,2-bis[4-(2-hydroxy-3-acryloxypropoxy)phenyl]-propane (BIS-GA), and other acrylate compounds contained in raw materials of ultraviolet-light-curable paint. The epoxy diacrylate gave an allergic patch test reaction down to 0.016% in pet. He also had an allergic patch test reaction to several other acrylate compounds, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, diethyleneglycol diacrylate, triethylene glycol diacrylate, and tripropylene glycol diacrylate, indicating cross and/or concomitant sensitization.

  2. Contact allergy to acrylates/methacrylates in the acrylate and nail acrylics series in southern Sweden: simultaneous positive patch test reaction patterns and possible screening allergens.

    Science.gov (United States)

    Teik-Jin Goon, Anthony; Bruze, Magnus; Zimerson, Erik; Goh, Chee-Leok; Isaksson, Marléne

    2007-07-01

    In a recent study we showed that all our dental personnel/patients were detected with 2-hydroxyethyl methacrylate (2-HEMA) and 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (bis-GMA). We studied 90 patients tested to the acrylate and nail acrylics series at our department over a 10 year period to see whether screening allergens could be found. Patch testing with an acrylate and nail acrylics series was performed. Among the 10 acrylate/methacrylate-allergic occupational dermatitis patients tested to the acrylate series, the most common allergens were triethyleneglycol diacrylate (TREGDA, 8), diethyleneglycol diacrylate (5), and 1,4-butanediol diacrylate (BUDA, 5). All 10 of these patients would have been picked up by a short screening series combining TREGDA, 2-hydroxypropyl methacrylate (2-HPMA), and BUDA or 1,6-hexanediol diacrylate (HDDA). Among the 14 acrylate/methacrylate-allergic nail patients, the most common allergens were ethylene glycol dimethacrylate (EGDMA, 11), 2-HEMA, (9), and triethyleneglycol dimethacrylate (9). Screening for 3 allergens i.e. 2-HEMA plus EGDMA plus TREGDA, would have detected all 14 nail patients. A short screening series combining 2-HEMA, EGDMA, TREGDA, 2-HPMA, bis-GMA, and BUDA or HDDA would have picked up all our past study patients (dental, industrial, and nail) with suspected allergy to acrylate/methacrylate allergens.

  3. On-line monitoring of bioreactions of Bacillus polymyxa and Klebsiella oxytoca by membrane introduction tandem mass spectrometry with flow injection analysis sampling

    Energy Technology Data Exchange (ETDEWEB)

    Hayward, M.J.; Kotiaho, Tapio; Lister, A.K.; Cooks, R.G.; Austin, G.D.; Narayan, Ramani; Tsao, G.T. (Purdue Univ., West Lafayette, IN (USA))

    1990-09-01

    Membrane introduction mass spectrometry with flow injection analysis sampling has been utilized for on-line monitoring of the major products and the volatile metabolites of fermentation of the Bacillus polymyxa and Klebsiella oxytoca organisms. A flow injection sampling system was used to rapidly deliver fermentation broth or an external standard to the mass spectrometer. Analyte introduction occurred via a direct insertion membrane probe in which the aqueous solutions flowed past a membrane located within the ion source of the mass spectrometer. For both organisms, concentrations of the liquid-phase products acetic acid, acetoin, 2,3-butanediol, and ethanol, were monitored as a function of time after permeation through the membrane and ionization by chemical ionization. Tandem mass spectrometry confirmed that these measurements were made without interference. Off-line gas chromatography was utilized to test the accuracy of these measurements, and excellent agreement was found. The use of tandem mass spectrometry has allowed the detection of additional compounds that were previously not known to be present in measurable amounts.

  4. Catalyst Influence on Undesired Side Reactions in the Polycondensation of Fully Bio-Based Polyester Itaconates

    Directory of Open Access Journals (Sweden)

    Ina Schoon

    2017-12-01

    Full Text Available Bio-based unsaturated polyester resins derived from itaconic acid can be an alternative to established resins of this type in the field of radical-curing resins. However, one of the challenges of these polyester itaconates is the somewhat more elaborate synthetic process, especially under polycondensation conditions used on an industrial scale. The α,β-unsaturated double bond of the itaconic acid is prone to side reactions that can lead to the gelation of the polyester resin under standard conditions. This is especially true when bio-based diols such as 1,3-propanediol or 1,4-butanediol are used to obtain resins that are 100% derived from renewable resources. It was observed in earlier studies that high amounts of these aliphatic diols in the polyester lead to low conversion and gelation of the resins. In this work, a catalytic study using different diols was performed in order to elucidate the reasons for this behavior. It was shown that the choice of catalyst has a crucial influence on the side reactions occurring during the polycondensation reactions. In addition, the side reactions taking place were identified and suppressed. These results will allow for the synthesis of polyester itaconates on a larger scale, setting the stage for their industrial application.

  5. Porous ovalbumin scaffolds with tunable properties: a resource-efficient biodegradable material for tissue engineering applications.

    Science.gov (United States)

    Luo, Baiwen; Choong, Cleo

    2015-01-01

    Natural materials are promising alternatives to synthetic materials used in tissue engineering applications as they have superior biocompatibility and promote better cell attachment and proliferation. Ovalbumin, a natural polymer found in avian egg white, is an example of a nature-derived material. Despite the availability and reported biocompatibility of ovalbumin, limited research has been carried out to investigate the efficacy of ovalbumin-based scaffolds for adipose tissue engineering applications. Hence, the current study was carried out to investigate the effect of different crosslinkers on ovalbumin scaffold properties as first step towards the development of ovalbumin-based scaffolds for adipose tissue engineering applications. In this study, highly porous three-dimensional scaffolds were fabricated by using three different crosslinkers: glutaraldehyde, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and 1,4-butanediol diglycidyl ether. Results showed that the overall scaffold properties such as morphology, pore size and mechanical properties could be modulated based on the type and concentration of crosslinkers used during the fabrication process. Subsequently, the efficacy of the different scaffolds for supporting cell proliferation was investigated. In vitro degradation was also carried on for the best scaffold based on the mechanical and cellular results. Overall, this study is a demonstration of the viability of ovalbumin-based scaffolds as cell carriers for soft tissue engineering applications. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  6. [Research progress in salting-out extraction of bio-based chemicals].

    Science.gov (United States)

    Dai, Jianying; Liu, Chunjiao; Sun, Yaqin; Xiu, Zhilong

    2013-10-01

    Bio-refinery using cheap biomass focuses mainly on strain improvement and fermentation strategies whereas less effort is made on down-stream processing. Using cheap biomass more impurities are introduced into the fermentation broths than mono-sugar substrate, thus down-stream processing for bio-based chemicals becomes the key problem in industrial production. The technique called salting-out extraction (SOE) was introduced in this review, which is used to separate target products from fermentation broth on the basis of partition difference of chemicals in two phases formed by mixing salts and organic solvents (or amphipathic chemicals) with broth at suitable ratios. The effect of solvents and salts on the formation of two aqueous phases, especially short chain alcohols and inorganic salts, and the application of SOE in recovery of bio-based chemicals, such as lactic acid, 1,3-propanediol, 2,3-butanediol and acetoin were summarized. The bio-chemicals were efficiently recovered from fermentation broth, and most of the impurities (cells and proteins) were removed in the same step. This technique is promising in the separation of bio-based chemicals, especially the recovery of hydrophilic molecules with low molecular weights.

  7. Use of Schizosaccharomyces pombe and Torulaspora delbrueckii strains in mixed and sequential fermentations to improve red wine sensory quality.

    Science.gov (United States)

    Loira, Iris; Morata, Antonio; Comuzzo, Piergiorgio; Callejo, María Jesús; González, Carmen; Calderón, Fernando; Suárez-Lepe, José Antonio

    2015-10-01

    One of the main opportunities in the use of non-Saccharomyces yeasts is its great intraspecific variability in relation to the synthesis of secondary products of fermentation. Thus, mixed or sequential fermentation with non-Saccharomyces can increase the synthesis of certain metabolites that are important for colour stability, such as acetaldehyde and pyruvic acid (vitisin precursors) or vinylphenols (vinylphenolic pyranoanthocyanin precursors). Furthermore, the selection and use of non-Saccharomyces yeast strains with good yields in the production of certain volatile compounds (ethyl lactate, 2,3-butanediol, 2-phenylethyl acetate), with limited formation of higher alcohols, is a way to improve the aromatic profile of red wine. The main aim of this work was to evaluate the influence of sequential and mixed fermentations with Schizosaccharomyces pombe and Torulaspora delbrueckii strains on red wine's sensory quality. Anthocyanins and aromatic profiles, as well as glycerol and organic acid content, were analysed in the red wines obtained. Results show that, in general, mixed fermentations can promote an increment in polyols synthesis, while sequential fermentations can enhance the herbaceous aroma. Moreover, the use of T. delbrueckii in mixed fermentations allowed an increase to the fruity character of red wine. The use of S. pombe in sequential fermentations increased the stability of the colouring matter by favouring vitisins and vinylphenolic pyranoanthocyanin formation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Construction of CoA-dependent 1-butanol synthetic pathway functions under aerobic conditions in Escherichia coli.

    Science.gov (United States)

    Kataoka, Naoya; Vangnai, Alisa S; Pongtharangkul, Thunyarat; Tajima, Takahisa; Yakushi, Toshiharu; Matsushita, Kazunobu; Kato, Junichi

    2015-06-20

    1-Butanol is an important industrial platform chemical and an advanced biofuel. While various groups have attempted to construct synthetic pathways for 1-butanol production, efforts to construct a pathway that functions under aerobic conditions have met with limited success. Here, we constructed a CoA-dependent 1-butanol synthetic pathway that functions under aerobic conditions in Escherichia coli, by expanding the previously reported (R)-1,3-butanediol synthetic pathway. The pathway consists of phaA (acetyltransferase) and phaB (NADPH-dependent acetoacetyl-CoA reductase) from Ralstonia eutropha, phaJ ((R)-specific enoyl-CoA hydratase) from Aeromonas caviae, ter (trans-enoyl-CoA reductase) from Treponema denticola, bld (butylraldehyde dehydrogenase) from Clostridium saccharoperbutylacetonicum, and inherent alcohol dehydrogenase(s) from E. coli. To evaluate the potential of this pathway for 1-butanol production, culture conditions, including volumetric oxygen transfer coefficient (kLa) and pH were optimized in a mini-jar fermenter. Under optimal conditions, 1-butanol was produced at a concentration of up to 8.60gL(-1) after 46h of fed-batch cultivation. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Synthesis and characterization of new hydroxycarboxylate compounds obtained in the redox reaction between Fe(NO{sub 3}){sub 3} and diol

    Energy Technology Data Exchange (ETDEWEB)

    Stefanescu, O., E-mail: oana.stefanescu@chim.upt.ro [Politehnica University of Timisoara, Faculty of Industrial Chemistry and Environmental Engineering, P-ta Victoriei No. 2, Timisoara, RO-300006 (Romania); Vlase, T.; Vlase, G.; Doca, N. [West University of Timisoara, Research Center for Thermal Analysis in Environmental Problems, Str. Pestalozzi No. 16, Timisoara, RO-300115 (Romania); Stefanescu, M. [Politehnica University of Timisoara, Faculty of Industrial Chemistry and Environmental Engineering, P-ta Victoriei No. 2, Timisoara, RO-300006 (Romania)

    2011-05-20

    Highlights: {yields} New hydroxycarboxylate compounds obtained in the redox reaction Fe(NO{sub 3}){sub 3}-diols. {yields} Octahedral stereochemistry with [Fe(III)O{sub 6}] chromophore for the synthesized complexes. {yields} Fe(III) glyoxylate and succinate as precursors of iron oxide {gamma}-Fe{sub 2}O{sub 3} nanoparticles. - Abstract: The paper presents experimental studies and structural investigations of two new Fe(III) hydroxycarboxylate coordination compounds. The homopolynuclear complex combinations of Fe(III) glyoxylate and succinate type were obtained in the redox reaction between Fe(NO{sub 3}){sub 3} and diols (1,2-ethanediol and 1,4-butanediol). The synthesized coordination compounds and the products formed during their thermal conversion were characterized by thermal analysis (in air and nitrogen), FT-IR and UV-VIS spectrometry, Moessbauer spectrometry, electron microscopy and XRD. By thermal decomposition of the complex combinations, at 300 {sup o}C, the well crystallized pure phase {gamma}-Fe{sub 2}O{sub 3} as nanoparticles were formed.

  10. Enzyme-catalyzed synthesis of unsaturated aliphatic polyesters based on green monomers from renewable resources.

    Science.gov (United States)

    Jiang, Yi; Woortman, Albert J J; van Ekenstein, Gert O R Alberda; Loos, Katja

    2013-08-12

    Bio-based commercially available succinate, itaconate and 1,4-butanediol are enzymatically co-polymerized in solution via a two-stage method, using Candida antarctica Lipase B (CALB, in immobilized form as Novozyme® 435) as the biocatalyst. The chemical structures of the obtained products, poly(butylene succinate) (PBS) and poly(butylene succinate-co-itaconate) (PBSI), are confirmed by 1H- and 13C-NMR. The effects of the reaction conditions on the CALB-catalyzed synthesis of PBSI are fully investigated, and the optimal polymerization conditions are obtained. With the established method, PBSI with tunable compositions and satisfying reaction yields is produced. The 1H-NMR results confirm that carbon-carbon double bonds are well preserved in PBSI. The differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) results indicate that the amount of itaconate in the co-polyesters has no obvious effects on the glass-transition temperature and the thermal stability of PBS and PBSI, but has significant effects on the melting temperature.

  11. Synthesis of graphene oxide grafted poly(lactic acid) with palladium nanoparticles and its application to serotonin sensing

    Science.gov (United States)

    Han, Hyoung Soon; You, Jung-Min; Jeong, Haesang; Jeon, Seungwon

    2013-11-01

    Graphene oxide (GO) has treated with methylene diphenyl diisocyanate (MDI) and subsequent 1,4-butanediol (BD) to create an anchoring OH site on the surface of GO (GO-MDI-OH). The OH groups of GO-MDI-OH were the initiators of the polymerization of poly(lactic acid) (PLA). The subsequent GO-g-PLA was synthesized by the polymerization reaction in the presence of GO-MDI-OH and PLA. The synthesized materials were characterized via 1H-NMR, Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), thermal analysis (differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA)). The surface morphologies and degree of dispersions at G-g-PLA-metals were observed using a field emission scanning electron microscope (FE-SEM) and a transmission electron microscopy (TEM). The electrical conductivity of G-g-PLA-Pd was largely enhanced compared with those of GO and GO-g-PLA. G-g-PLA-Pd was used for the electrochemical detection of serotonin. Electrocatalytic activities were verified from the cyclic voltammetry (CV) and amperometric response in a 0.1 M phosphate buffer solution (PBS). A significantly higher concentration range (0.1-100.0 μM) and a lower detection limit (8.0 × 10-8 M, where s/n = 3) were found at the G-g-PLA-Pd modified glassy carbon electrode (GCE).

  12. Polyesteramide-derived nonwovens as innovative degradable matrices support preadipocyte adhesion, proliferation, and differentiation.

    Science.gov (United States)

    Hemmrich, K; Meersch, M; Wiesemann, U; Salber, J; Klee, D; Gries, Th; Pallua, N

    2006-12-01

    Extended soft tissue defects resulting from injuries or tumor resections are still an unresolved problem in plastic and reconstructive surgery because adequate reconstruction is difficult. Immature adipogenic precursor cells, called preadipocytes, which are located between mature adipocytes in adipose tissue, represent a powerful tool for soft tissue engineering because of their ability to proliferate and differentiate into adipose tissue after transplantation. In previous studies, we compared preadipocyte-loaded hyaluronan or collagen biomaterials and their applicability for adipose tissue engineering. Our findings demonstrated successful de novo formation of adipose tissue in vivo but pore size and stiffness were limiting factors not allowing for sufficient cell distribution in the construct. This study presents a nonwoven made of novel bioabsorbable co-poly(ester amide) based on e-caprolactam, adipic acid, and 1,4-butanediol in an innovative 3-dimensional architecture. The material was formed into nonwovens by textile manufacturing using an aerodynamic web formation process and a needle felting technique. Carriers were seeded with human preadipocytes and examined for cellular proliferation and differentiation. In addition, methods of preparing scaffolds for optimal cell interaction were evaluated. Our findings show that polyesteramide-derived nonwovens allow good adherence, proliferation, and differentiation of preadipocytes. These results are promising guidance toward an optimally designed scaffold for in vivo use.

  13. Pan-genomic and transcriptomic analyses of Leuconostoc mesenteroides provide insights into its genomic and metabolic features and roles in kimchi fermentation.

    Science.gov (United States)

    Chun, Byung Hee; Kim, Kyung Hyun; Jeon, Hye Hee; Lee, Se Hee; Jeon, Che Ok

    2017-09-14

    The genomic and metabolic features of Leuconostoc (Leu) mesenteroides were investigated through pan-genomic and transcriptomic analyses. Relatedness analysis of 17 Leu. mesenteroides strains available in GenBank based on 16S rRNA gene sequence, average nucleotide identity, in silico DNA-DNA hybridization, molecular phenotype, and core-genome indicated that Leu. mesenteroides has been separated into different phylogenetic lineages. Pan-genome of Leu. mesenteroides strains, consisting of 999 genes in core-genome, 1,432 genes in accessory-genome, and 754 genes in unique genome, and their COG and KEGG analyses showed that Leu. mesenteroides harbors strain-specifically diverse metabolisms, probably representing high evolutionary genome changes. The reconstruction of fermentative metabolic pathways for Leu. mesenteroides strains showed that Leu. mesenteroides produces various metabolites such as lactate, ethanol, acetate, CO 2 , mannitol, diacetyl, acetoin, and 2,3-butanediol through an obligate heterolactic fermentation from various carbohydrates. Fermentative metabolic features of Leu. mesenteroides during kimchi fermentation were investigated through transcriptional analyses for the KEGG pathways and reconstructed metabolic pathways of Leu. mesenteroides using kimchi metatranscriptomic data. This was the first study to investigate the genomic and metabolic features of Leu. mesenteroides through pan-genomic and metatranscriptomic analyses, and may provide insights into its genomic and metabolic features and a better understanding of kimchi fermentations by Leu. mesenteroides.

  14. Control of the anisotropic shape of cobalt nanorods in the liquid phase: from experiment to theory… and back.

    Science.gov (United States)

    Atmane, Kahina Aït; Michel, Carine; Piquemal, Jean-Yves; Sautet, Philippe; Beaunier, Patricia; Giraud, Marion; Sicard, Mickaël; Nowak, Sophie; Losno, Rémi; Viau, Guillaume

    2014-03-07

    The polyol process is one of the few methods allowing the preparation of metal nanoparticles in solution. Hexagonal close packed monocrystalline Co nanorods are easily obtained in basic 1,2-butanediol at 448 K after a few minutes using a Co(II) dicarboxylate precursor. By using a combined experimental and theoretical approach, this study aims at a better understanding of the growth of anisotropic cobalt ferromagnetic nanoparticles by the polyol process. The growth of Co nanorods along the c axis of the hexagonal system was clearly evidenced by transmission electron microscopy, while the mean diameter was found to be almost constant at about 15 nm. Powder X-ray diffraction data showed that metallic cobalt was generated at the expense of a non-reduced solid lamellar intermediate phase which can be considered as a carboxylate ligand reservoir. Density functional theory calculations combined with a thermodynamic approach unambiguously showed that the main parameter governing the shape of the objects is the chemical potential of the carboxylate ligand: the crystal habit was deeply modified from rods to platelets when increasing the concentration of the ligand, i.e. its chemical potential. The approach presented in this study could be extended to a large number of particle types and growth conditions, where ligands play a key role in determining the particle shape.

  15. Anion exchangers with negatively charged functionalities in hyperbranched ion-exchange layers for ion chromatography.

    Science.gov (United States)

    Uzhel, Anna S; Zatirakha, Alexandra V; Smirnov, Konstantin N; Smolenkov, Alexandr D; Shpigun, Oleg A

    2017-01-27

    Novel pellicular poly(styrene-divinylbenzene)-based (PS-DVB) anion exchangers with covalently-bonded hyperbranched functional ion-exchange layers containing negatively charged functionalities are obtained and examined. The hyperbranched coating is created on the surface of aminated PS-DVB substrate by repeating the modification cycles including alkylation with 1,4-butanediol diglycidyl ether (1,4-BDDGE), and amination of the terminal epoxide rings with methylamine (MA) or glycine (Gly). The influence of the position and the number of the layers with glycine, as well as of the total number of the layers of amine in the coating on the chromatographic properties of the obtained stationary phases is investigated. Chromatographic performance of the obtained stationary phases is evaluated using the model mixtures of inorganic and organic anions with hydroxide eluent. It is shown that the best selectivity toward weakly retained organic acids and oxyhalides is possessed by the anion exchanger obtained after 5 modification cycles, with glycine being used in the first one. Such anion exchanger packed in 25-cm long column is capable of separating 22 anions in 58min including 7 standard anions, mono-, di- and trivalent organic acids, oxyhalides, and some other double- and triple-charged anions. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Viscosity-dependent drain current noise of AlGaN/GaN high electron mobility transistor in polar liquids

    Energy Technology Data Exchange (ETDEWEB)

    Fang, J. Y.; Hsu, C. P.; Kang, Y. W.; Fang, K. C.; Kao, W. L.; Yao, D. J.; Chen, C. C.; Li, S. S.; Yeh, J. A.; Wang, Y. L. [Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu 300, Taiwan (China); Lee, G. Y.; Chyi, J. I. [Department of Electrical engineering, National Central University, Jhongli City, Taoyuan County 32001, Taiwan (China); Hsu, C. H. [Division of Medical Engineering, National Health Research Institutes, MiaoLi, Taiwan (China); Huang, Y. F. [Department of Biomedical Engineering and Environmental Science, National Tsing Hua University, Hsinchu 300, Taiwan (China); Ren, F. [Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611 (United States)

    2013-11-28

    The drain current fluctuation of ungated AlGaN/GaN high electron mobility transistors (HEMTs) measured in different fluids at a drain-source voltage of 0.5 V was investigated. The HEMTs with metal on the gate region showed good current stability in deionized water, while a large fluctuation in drain current was observed for HEMTs without gate metal. The fluctuation in drain current for the HEMTs without gate metal was observed and calculated as standard deviation from a real-time measurement in air, deionized water, ethanol, dimethyl sulfoxide, ethylene glycol, 1,2-butanediol, and glycerol. At room temperature, the fluctuation in drain current for the HEMTs without gate metal was found to be relevant to the dipole moment and the viscosity of the liquids. A liquid with a larger viscosity showed a smaller fluctuation in drain current. The viscosity-dependent fluctuation of the drain current was ascribed to the Brownian motions of the liquid molecules, which induced a variation in the surface dipole of the gate region. This study uncovers the causes of the fluctuation in drain current of HEMTs in fluids. The results show that the AlGaN/GaN HEMTs may be used as sensors to measure the viscosity of liquids within a certain range of viscosity.

  17. Novel Psychoactive Substances-Recent Progress on Neuropharmacological Mechanisms of Action for Selected Drugs.

    Science.gov (United States)

    Hassan, Zurina; Bosch, Oliver G; Singh, Darshan; Narayanan, Suresh; Kasinather, B Vicknasingam; Seifritz, Erich; Kornhuber, Johannes; Quednow, Boris B; Müller, Christian P

    2017-01-01

    A feature of human culture is that we can learn to consume chemical compounds, derived from natural plants or synthetic fabrication, for their psychoactive effects. These drugs change the mental state and/or the behavioral performance of an individual and can be instrumentalized for various purposes. After the emergence of a novel psychoactive substance (NPS) and a period of experimental consumption, personal and medical benefits and harm potential of the NPS can be estimated on evidence base. This may lead to a legal classification of the NPS, which may range from limited medical use, controlled availability up to a complete ban of the drug form publically accepted use. With these measures, however, a drug does not disappear, but frequently continues to be used, which eventually allows an even better estimate of the drug's properties. Thus, only in rare cases, there is a final verdict that is no more questioned. Instead, the view on a drug can change from tolerable to harmful but may also involve the new establishment of a desired medical application to a previously harmful drug. Here, we provide a summary review on a number of NPS for which the neuropharmacological evaluation has made important progress in recent years. They include mitragynine ("Kratom"), synthetic cannabinoids (e.g., "Spice"), dimethyltryptamine and novel serotonergic hallucinogens, the cathinones mephedrone and methylone, ketamine and novel dissociative drugs, γ-hydroxybutyrate, γ-butyrolactone, and 1,4-butanediol. This review shows not only emerging harm potentials but also some potential medical applications.

  18. Reversibility of strain stiffening in silk fibroin gels.

    Science.gov (United States)

    Oztoprak, Zeynep; Okay, Oguz

    2017-02-01

    We investigate the linear and nonlinear viscoelastic properties as well as the reversibility of strain-stiffening behavior of silk fibroin gels. The gels are prepared from 4.2w/v% fibroin solution in the presence of butanediol diglycidyl ether and N,N,N',N'-tetramethylethylenediamine (TEMED) as a cross-linker and catalyst, respectively. By changing the concentration of TEMED in the gelation system, fibroin gels exhibiting a storage modulus G' between 10-1-105Pa and a loss factor tan δ between 10-2 and 10° could be obtained. We observe a strong stiffening (up to 900%) in fibroin gels with increasing strain above 10% deformation, but reversibly if the strain is removed, the gel recovers its initial viscoelastic properties. The strain induced formation of transient intermolecular domains acting as reversible cross-links are responsible for the stiffening behavior of fibroin gels. These additional cross-links formed in the hardened fibroin gels have a temporary nature with lifetimes of the order of seconds. The nonlinear behavior of fibroin gels can be reproduced by a wormlike chain model taking into account the entropic elasticity of fibroin molecules and the strain induced increase in the cross-link density of fibroin gels. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Transparent large-strain thermoplastic polyurethane magnetoactive nanocomposites.

    Science.gov (United States)

    Yoonessi, Mitra; Peck, John A; Bail, Justin L; Rogers, Richard B; Lerch, Bradley A; Meador, Michael A

    2011-07-01

    Organically modified superparamagnetic MnFe(2)O(4)/thermoplastic polyurethane elastomer (TPU) nanocomposites (0.1-8 wt %) were prepared by solvent mixing followed by solution casting. Linear aliphatic alkyl chain modification of spherical MnFe(2)O(4) provided compatibility with the TPU containing a butanediol extended polyester polyol-MDI. All MnFe(2)O(4)/TPU nanocomposite films were superparamagnetic and their saturation magnetization, σ(s), increased with increasing MnFe(2)O(4) content. All nanocomposite films exhibited large deformations (>10 mm) under a magneto-static field. This is the first report of large actuation of magnetic nanoparticle nanocomposites at low-loading levels of 0.1 wt % (0.025 vol %). The maximum actuation deformation of the MnFe(2)O(4)/TPU nanocomposite films increased exponentially with increasing nanoparticle concentration. An empirical correlation between the maximum displacement, saturation magnetization, and magnetic nanoparticle loading is proposed. The cyclic deformation actuation of a 6 wt % surface modified MnFe(2)O(4)/TPU, in a low magnetic field 151 < B(y) < 303 Oe, exhibited excellent reproducibility and controllability. MnFe(2)O(4)/TPU nanocomposite films (0.1-2 wt %) were transparent and semitransparent over the wavelengths from 350 to 700 nm.

  20. Inhibitory Effects of Chemical Compounds Isolated from the Rhizome of Smilax glabra on Nitric Oxide and Tumor Necrosis Factor-α Production in Lipopolysaccharide-Induced RAW264.7 Cell

    Directory of Open Access Journals (Sweden)

    Chuan-li Lu

    2015-01-01

    Full Text Available The rhizome of Smilax glabra has been used for a long time as both food and folk medicine in many countries. The present study focused on the active constituents from the rhizome of S. glabra, which possess potential anti-inflammatory activities. As a result, nine known compounds were isolated from the rhizome of S. glabra with the bioassay-guiding, and were identified as syringaresinol (1, lasiodiplodin (2, de-O-methyllasiodiplodin (3, syringic acid (4, 1,4-bis(4-hydroxy-3,5-dimethoxyphenyl-2,3-bis(hydroxymethyl-1,4-butanediol (5, lyoniresinol (6, trans-resveratrol (7, trans-caffeic acid methyl ester (8, and dihydrokaempferol (9. Among these compounds, 2 and 3 were isolated for the first time from S. glabra. In addition, the potential anti-inflammatory activities of the isolated compounds were evaluated in vitro in lipopolysaccharide- (LPS- induced RAW264.7 cells. Results indicated that 4 and 7 showed significant inhibitory effects on NO production of RAW264.7 cells, and 1, 2, 3, and 5 showed moderate suppression effects on induced NO production. 1, 7, and 5 exhibited high inhibitory effects on TNF-α production, with the IC50 values less than 2.3, 4.4, and 16.6 μM, respectively. These findings strongly suggest that compounds 1, 2, 3, 4, 5, 7, and 9 were the potential anti-inflammatory active compositions of S. glabra.

  1. Novel monosaccharide fermentation products in Caldicellulosiruptor saccharolyticus identified using NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Isern, Nancy G.; Xue, Junfeng; Rao, Jaya V.; Cort, John R.; Ahring, Birgitte K.

    2013-04-03

    Profiles of metabolites produced by the thermophilic obligately anaerobic cellulose-degrading Gram-positive bacterium Caldicellulosiruptor saccharolyticus DSM 8903 strain following growth on different monosaccharides (D-glucose, D-mannose, L-arabinose, D-arabinose, D-xylose, L-fucose, and D-fucose) as carbon sources revealed several unexpected fermentation products, suggesting novel metabolic capacities and unexplored metabolic pathways in this organism. Both 1H and 13C nuclear magnetic resonance (NMR) spectroscopy were used to determine intracellular and extracellular metabolite profiles. Metabolite profiles were determined from 1-D 1H NMR spectra by curve fitting against spectral libraries provided in Chenomx software. To reduce uncertainties due to unassigned, overlapping, or poorly-resolved peaks, metabolite identifications were confirmed with 2-D homonuclear and heteronuclear NMR experiments. In addition to expected metabolites such as acetate, lactate, glycerol, and ethanol, several novel fermentation products were identified: ethylene glycol (from growth on D-arabinose, though not L-arabinose), acetoin and 2,3-butanediol (from D-glucose and L-arabinose), and hydroxyacetone (from D-mannose and L-arabinose). Production of ethylene glycol from D-arabinose was particularly notable, with around 10% of the substrate carbon converted into this uncommon fermentation product. The novel products have not previously been reported to be produced by C. saccharolyticus, nor would they be easily predicted from the current genome annotation, and show new potentials for using this strain for production of bioproducts.

  2. Ketone ester supplementation attenuates seizure activity, and improves behavior and hippocampal synaptic plasticity in an Angelman syndrome mouse model.

    Science.gov (United States)

    Ciarlone, Stephanie L; Grieco, Joseph C; D'Agostino, Dominic P; Weeber, Edwin J

    2016-12-01

    Angelman syndrome (AS) is a rare genetic and neurological disorder presenting with seizures, developmental delay, ataxia, and lack of speech. Previous studies have indicated that oxidative stress-dependent metabolic dysfunction may underlie the phenotypic deficits reported in the AS mouse model. While the ketogenic diet (KD) has been used to protect against oxidative stress and has successfully treated refractory epilepsy in AS case studies, issues arise due to its strict adherence requirements, in addition to selective eating habits and weight issues reported in patients with AS. We hypothesized that ketone ester supplementation would mimic the KD as an anticonvulsant and improve the behavioral and synaptic plasticity deficits in vivo. AS mice were supplemented R,S-1,3-butanediol acetoacetate diester (KE) ad libitum for eight weeks. KE administration improved motor coordination, learning and memory, and synaptic plasticity in AS mice. The KE was also anticonvulsant and altered brain amino acid metabolism in AS treated animals. Our findings suggest that KE supplementation produces sustained ketosis and ameliorates many phenotypes in the AS mouse model, and should be investigated further for future clinical use. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  3. Determinação do parâmetro de solubilidade de poliuretanos de PBLH Solubility parameter of HTPB polyurethanes determination

    Directory of Open Access Journals (Sweden)

    Eder M. Santos

    2000-06-01

    Full Text Available O parâmetro de solubilidade de poliuretanos segmentados foi determinado através de ensaios de inchamento no equilíbrio, tratando-se os dados pela teoria de Flory-Rehner. O segmento flexível dos poliuretanos foi constituído por blocos de oligobutadieno e o segmento rígido foi formado pela reação entre di-isocianato de tolileno e os extensores de cadeia 1,3-propanodiol; 1,4-butanodiol; 1,6-hexanodiol e 2, 2'-di-hidroxi-isopropil N, N'anilina. O teor em segmento rígido para os polímeros provenientes dos extensores alifáticos ficou na faixa de 25,1% a 28,3%, enquanto que, nos polímeros estendidos com o extensor aromático, foi de 32,6%.The solubility parameter of a series of segmented polyurethanes was determined through equilibrium swelling experiments, using the Flory-Rehner theory. The soft segment of the polyurethanes was oligobutadiene and the hard block was formed through the reaction of tolylene diisocyanate with propanediol, butanediol, hexanediol or 2, 2' dihydroxy isopropyl N, N' aniline. The hard segment content in all polymers was about the same for the aliphatic extenders (25.1% to 28.3% and 32.6% for the aromatic one.

  4. Effect of roasting on the volatile constituents of Trichosanthes kirilowii seeds

    Directory of Open Access Journals (Sweden)

    Shimin Wu

    2014-09-01

    Full Text Available Roasted Trichosanthes kirilowii seeds have much more intense flavor than the raw seeds, and are commonly used as food and in the preparations of many medicinal formulations. Volatile constituents in the raw and roasted T. kirilowii seeds were separated by simultaneous distillation and extraction, and analyzed by gas chromatography–mass spectrometry on two capillary gas chromatography columns of different polarities (DB-WAX and HP-1. A total of 40 volatile compounds were identified in the raw seeds, with pentanal, 2-pentanol, styrene, (Z-2-heptenal, (+-calarene, and α-muurolene being the predominant compounds; 40 volatile compounds were also identified in the roasted seeds, with 3-methylbutanal, ethanol, 2-butanol, 2,3-butanediol, (E,E-2,4-nonadienal, and 2-isopropyl-5-methyl-9-methylene-bicyclo[4.4.0]dec-1-ene being the most abundant compounds. A total of 15 compounds, mostly aldehydes, were common in both seeds. Roasting of T. kirilowii seeds resulted in a significant decrease in the levels of sesquiterpenes and short-chain aliphatic aldehydes. By contrast, high concentrations of 3-methylbutanal, ethanol, 2-butanol, and alkyl pyrazines were generated, which was responsible for the unique flavor of the roasted seeds. The study results may be useful for optimizing the roasting process and oil processing of T. kirilowii seeds.

  5. A heuristic model of stone comminution in shock wave lithotripsy.

    Science.gov (United States)

    Smith, Nathan B; Zhong, Pei

    2013-08-01

    A heuristic model is presented to describe the overall progression of stone comminution in shock wave lithotripsy (SWL), accounting for the effects of shock wave dose and the average peak pressure, P+(avg), incident on the stone during the treatment. The model is developed through adaptation of the Weibull theory for brittle fracture, incorporating threshold values in dose and P+(avg) that are required to initiate fragmentation. The model is validated against experimental data of stone comminution from two stone types (hard and soft BegoStone) obtained at various positions in lithotripter fields produced by two shock wave sources of different beam width and pulse profile both in water and in 1,3-butanediol (which suppresses cavitation). Subsequently, the model is used to assess the performance of a newly developed acoustic lens for electromagnetic lithotripters in comparison with its original counterpart both under static and simulated respiratory motion. The results have demonstrated the predictive value of this heuristic model in elucidating the physical basis for improved performance of the new lens. The model also provides a rationale for the selection of SWL treatment protocols to achieve effective stone comminution without elevating the risk of tissue injury.

  6. Regenerable Subnanometer Pd Clusters on Zirconia for Highly Selective Hydrogenation of Biomass-Derived Succinic Acid in Water

    Directory of Open Access Journals (Sweden)

    Chi Zhang

    2016-07-01

    Full Text Available The size of metal particles is an important factor to determine the performance of the supported metal catalysts. In this work, we report subnanometer Pd clusters supported on zirconia by the microwave-assisted hydrothermal method. The presence of subnanometer Pd clusters on the zirconia surface was confirmed by two-dimensional Gaussian-function fits of the aberration-corrected high-angle annual dark-field images. These subnanometer Pd catalysts exhibit high catalytic performance for the hydrogenation of biomass-derived succinic acid to γ-butyrolactone in water and avoid the formation of overhydrogenated products, such as 1,4-butanediol and tetrahydrofuran. The catalyst with an ultra-low Pd loading of 0.2 wt. % demonstrated high selectivity (95% for γ-butyrolactone using water as a solvent at 473 K and 10 MPa. Moreover, it can be reused at least six times without the loss of catalytic activity, illustrating high performance of the small Pd clusters.

  7. Identification of bacteria in total mixed ration silage produced with and without crop silage as an ingredient.

    Science.gov (United States)

    Nishino, Naoki; Ogata, Yu; Han, Hongyan; Yamamoto, Yasunari

    2015-01-01

    As a forage source for total mixed ration (TMR) silage production, locally produced crop silage is now used in addition to imported hay. This type of TMR ensiling is regarded as a two-step fermentation process; hence, a survey was carried out to determine whether the bacteria in crop silage affect the subsequent TMR ensiling. Fermentation product contents and bacterial community were determined for TMR silage and its ingredient silages collected in August, October and November. August product contained corn, sorghum and Italian ryegrass silages, October product had wheat silage exclusively and November product did not include any crop silages. Acetic acid, lactic acid, 2,3-butanediol and ethanol were predominant fermentation products in corn, sorghum, Italian ryegrass and wheat silages, respectively. Robust lactic acid fermentation was seen in TMR silage, even if acetate-type and alcohol-type silages were mixed as ingredients. The finding that bacterial community of the TMR silage appeared unrelated to those of ingredient silage supported this. Silages of various fermentation types can therefore be formulated without interfering with lactate-type fermentation in TMR silage. © 2014 Japanese Society of Animal Science.

  8. Metabolism of lactose and citrate by mutants of Lactococcus lactis producing excess carbon dioxide.

    Science.gov (United States)

    El Attar, A; Monnet, C; Corrieu, G

    2000-11-01

    Mutants of Lactococcus lactis producing excess carbon dioxide could be isolated on LDHA-20 agar (described by El Attar et al. Journal of Dairy Research 67 641-646 2000). The use of these mutants in the manufacture of Roquefort cheese has the potential to improve the formation of openings in this cheese. The aim of this work was to examine the stability of these mutants, their enzymic activities and their metabolism of lactose and citrate during growth in milk. They produced less L-lactate than the parent strain and their lactate dehydrogenase activity was lower. Nevertheless none of the mutants produced no L-lactate at all and the most active gas generators among them generally produced 30-50 mM-L-lactate. Unexpectedly, all the strains produced some D-lactate, some > 10 mM. We found that carbon dioxide production by the mutants could be determined indirectly by assaying acetoin, citrate and 2,3-butanediol by high-performance liquid chromatography. Generally, spontaneous mutants were more stable than those obtained after treating with nitrosoguanidine or u.v. irradiation.

  9. Synthesis and characterization of shape-memory poly carbonate urethane microspheres for future vascular embolization.

    Science.gov (United States)

    Liu, Rongrong; Dai, Honglian; Zhou, Qian; Zhang, Qian; Zhang, Ping

    2016-08-01

    Two types of shape memory poly carbonate urethanes (PCUs) microspheres were synthesized by pre-polymerization and suspension polymerization, based on Polycarbonate diol (PCDL) as the soft segment, Isophorone diisocyanate (IPDI) and 1,6-hexamethylene diisocyanate (HDI) as the hard segments and 1,4-butanediol (BDO) as the chain expanding agent. The structure, crystallinity, and thermal property of the two synthesized PCUs were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Differential scanning calorimetery (DSC), respectively. The results showed that the two types of PCUs exhibited high thermal stability with phase separation and semi-crystallinity. Also, the results of the compression test displayed that the shape fixity and the shape recovery of two PCUs were more than 90% compared to the originals, indicating their similar bio-applicability and shape-memory properties. The tensile strength, elongation at break was enhanced by introducing and increasing content of HDI. The water contact angles of PCUs decreased and their surface tension increased by surface modified with Bovine serum albumin (BSA). Furthermore, the biological study results of two types of PCUs from the platelet adhesion test and the cell proliferation inhibition test indicated they had some biocompatibilites. Hence, the PCU microspheres might represent a smart and shape-memory embolic agent for vascular embolization.

  10. Plant growth promoting rhizobia: challenges and opportunities.

    Science.gov (United States)

    Gopalakrishnan, Subramaniam; Sathya, Arumugam; Vijayabharathi, Rajendran; Varshney, Rajeev Kumar; Gowda, C L Laxmipathi; Krishnamurthy, Lakshmanan

    2015-08-01

    Modern agriculture faces challenges, such as loss of soil fertility, fluctuating climatic factors and increasing pathogen and pest attacks. Sustainability and environmental safety of agricultural production relies on eco-friendly approaches like biofertilizers, biopesticides and crop residue return. The multiplicity of beneficial effects of microbial inoculants, particularly plant growth promoters (PGP), emphasizes the need for further strengthening the research and their use in modern agriculture. PGP inhabit the rhizosphere for nutrients from plant root exudates. By reaction, they help in (1) increased plant growth through soil nutrient enrichment by nitrogen fixation, phosphate solubilization, siderophore production and phytohormones production (2) increased plant protection by influencing cellulase, protease, lipase and β-1,3 glucanase productions and enhance plant defense by triggering induced systemic resistance through lipopolysaccharides, flagella, homoserine lactones, acetoin and butanediol against pests and pathogens. In addition, the PGP microbes contain useful variation for tolerating abiotic stresses like extremes of temperature, pH, salinity and drought; heavy metal and pesticide pollution. Seeking such tolerant PGP microbes is expected to offer enhanced plant growth and yield even under a combination of stresses. This review summarizes the PGP related research and its benefits, and highlights the benefits of PGP rhizobia belonging to the family Rhizobiaceae, Phyllobacteriaceae and Bradyrhizobiaceae.

  11. Phytoremediation of heavy and transition metals aided by legume-rhizobia symbiosis.

    Science.gov (United States)

    Hao, X; Taghavi, S; Xie, P; Orbach, M J; Alwathnani, H A; Rensing, C; Wei, G

    2014-01-01

    Legumes are important for nitrogen cycling in the environment and agriculture due to the ability of nitrogen fixation by rhizobia. In this review, we introduce an important and potential role of legume-rhizobia symbiosis in aiding phytoremediation of some metal contaminated soils as various legumes have been found to be the dominant plant species in metal contaminated areas. Resistant rhizobia used for phytoremediation could act on metals directly by chelation, precipitation, transformation, biosorption and accumulation. Moreover, the plant growth promoting (PGP) traits of rhizobia including nitrogen fixation, phosphorus solubilization, phytohormone synthesis, siderophore release, and production of ACC deaminase and the volatile compounds of acetoin and 2, 3-butanediol may facilitate legume growth while lessening metal toxicity. The benefits of using legumes inoculated with naturally resistant rhizobia or recombinant rhizobia with enhanced resistance, as well as co-inoculation with other plant growth promoting bacteria (PGPB) are discussed. However, the legume-rhizobia symbiosis appears to be sensitive to metals, and the effect of metal toxicity on the interaction between legumes and rhizobia is not clear. Therefore, to obtain the maximum benefits from legumes assisted by rhizobia for phytoremediation of metals, it is critical to have a good understanding of interactions between PGP traits, the symbiotic plant-rhizobia relationship and metals.

  12. Thermal stability of beta-lactoglobulin in the presence of aqueous solution of alcohols and polyols.

    Science.gov (United States)

    Romero, Carmen M; Lozano, José M; Sancho, Javier; Giraldo, Gloria I

    2007-04-10

    A systematic study concerning the effect of aqueous solution of alcohols and polyols with four carbon atoms on beta-lactoglobulin stability is presented. The protein was chosen due to its functional properties and applications in food and pharmaceutical industries and because its structure and properties in aqueous solution have been widely described. The alcohols having a four carbon chain were selected to examine the effect of the gradual increase in the number of OH groups on protein stability. Protein thermal stability in water, buffers and dilute aqueous solutions of 1-butanol, 1,2-butanediol, 1,2,4-butanetriol and 1,2,3,4-butanetetrol was evaluated by fluorescence spectroscopy. The results were used to determine the temperature range in which the unfolding process is reversible and the protein denaturation temperature in acetate buffer pH 5.5 and in the aqueous mixed solvents. Thermodynamic results show that alcohol denaturating effect diminishes gradually as the number of OH groups increase.

  13. Application of reactive siloxane prepolymers for the synthesis of thermoplastic poly(ester–siloxanes and poly(ester–ether–siloxanes

    Directory of Open Access Journals (Sweden)

    VESNA V. ANTIC

    2007-02-01

    Full Text Available Thermoplastic poly(ester–siloxanes (TPES and poly(ester–ether–siloxane s, (TPEES, based on poly(butylene terephthalate (PBT as the hard segment and different siloxane-prepolymers as the soft segments, were prepared. The TPES and TPEES were synthesized by catalyzed two-step transesterification from dimethyl terephthalate, (DMT, 1,4-butanediol, (BD and a siloxane-prepolymer. Incorporation of dicarboxypropyl- or disilanol-terminated poly(dimethylsiloxanes (PDMS into the polar poly(butylene terephthalate chains resulted in rather inhomogeneous TPES copolymers, which was a consequence of a prononuced phase separation of the polar and non-polar reactants during synthesis. Two concepts were employed to avoid or reduce phase separation: 1 the use of siloxane-containing triblock prepolymers with hydrophilic terminal blocks, such as ethylene oxide (EO, poly(propylene oxide (PPO or poly(caprolactone (PLC when the terminal blocks serve as a compatibilizer between the extremely non-polar PDMS and the polar DMT and BD, and 2 the use of a high-boiling solvent (1,2,4-trichlorobenzene during the first phase of the reaction. Homogeneity was significantly improved in the case of copolymers based on PCL–PDMS–PCL.

  14. [Influence of ZSM-5(38)/Al-MCM-41 composite molecular sieve catalysts on pyrolysis of cellulose].

    Science.gov (United States)

    Liu, Xiaojuan; Yu, Fengwen; Nie, Yong; Luo, Yao; Ji, Jianbing

    2011-03-01

    Pyrolysis of cellulose with different catalysts has been conducted in a fixed-bed reactor. Micro-mesoporous composite molecular sieves of ZSM-5(38)/A1-MCM-41 with different Si/A1 ratios were prepared under hydrothermal conditions. With powder X-ray diffraction (XRD), the catalyst samples were characterized. GC-MS was used to analyze the bio-oil composition. The effects of catalysts on the pyrolysis product yields were investigated and the results were compared with the results of experiments performed without catalyst under the same pyrolitic conditions. The presence of the catalysts decreased the liquid yield, while increased the moisture content. The major improvement in the quality of bio-oil with the use of catalysts was the increase of DL-2,3-Butanediol. ZSM-5(38)/A1-MCM-41(20) favored the formation of phenol and 2-methoxy-phenol. In addition, these catalysts were all benefit for the generation of small molecular compounds. Also, it was found that ZSM-5(38) was better for the production of C4-C5 compounds. And micro-mesoporous composite molecular sieves mainly promoted the production of C6-C8 compounds.

  15. Impact of the poly(propylene oxide-b-poly(dimethylsiloxane-b-poly(propylene oxide macrodiols on the surface related properties of polyurethane copolymers

    Directory of Open Access Journals (Sweden)

    Stefanović Ivan S.

    2016-01-01

    Full Text Available Segmented thermoplastic polyurethane copolymers (PURs were synthesized using 4,4'-methylenediphenyl diisocyanate and 1,4-butanediol as the hard segment and α,ω-dihydroxy-poly(propylene oxide-b-poly(dimethylsiloxane-b-poly(propylene oxide (PPO-PDMS as the soft segment. The content of incorporated soft segments in PURs varied in the range from 40 to 90 wt.%. The structure, molecular weights and crystallinity of obtained copolymers were monitored by FTIR, 1H, 2D NMR spectroscopy, GPC and DSC analysis, respectively. Surface free energy analysis indicates the presence of hydrophobic (siloxane groups on the surface, giving highly hydrophobic nature to the obtained PURs films. Water absorption measurements showed that the increase of the hydrophobic PPO-PDMS segment content, led to the decrease of percentage of absorbed water in copolymers. SEM and AFM analysis revealed that copolymers with lower content of PPO-PDMS segments have higher microphase separation between segments. The results obtained in this work indicate that synthesized PURs based on PPO-PDMS, demonstrated proper surface and morphological properties with a great potential for variety of applications such as hydrophobic coatings in biomedicine. [Projekat Ministarstva nauke Republike Srbije, br. 172062

  16. Nutritional Value and Volatile Compounds of Black Cherry (Prunus serotina Seeds

    Directory of Open Access Journals (Sweden)

    Leticia García-Aguilar

    2015-02-01

    Full Text Available Prunus serotina (black cherry, commonly known in Mexico as capulín, is used in Mexican traditional medicine for the treatment of cardiovascular, respiratory, and gastrointestinal diseases. Particularly, P. serotina seeds, consumed in Mexico as snacks, are used for treating cough. In the present study, nutritional and volatile analyses of black cherry seeds were carried out to determine their nutraceutical potential. Proximate analysis indicated that P. serotina raw and toasted seeds contain mostly fat, followed by protein, fiber, carbohydrates, and ash. The potassium content in black cherry raw and toasted seeds is high, and their protein digestibility-corrected amino acid scores suggest that they might represent a complementary source of proteins. Solid phase microextraction and gas chromatography/flame ionization detection/mass spectrometry analysis allowed identification of 59 and 99 volatile compounds in the raw and toasted seeds, respectively. The major volatile compounds identified in raw and toasted seeds were 2,3-butanediol and benzaldehyde, which contribute to the flavor and odor of the toasted seeds. Moreover, it has been previously demonstrated that benzaldehyde possesses a significant vasodilator effect, therefore, the presence of this compound along with oleic, linoleic, and α-eleostearic fatty acids indicate that black cherry seeds consumption might have beneficial effects on the cardiovascular system.

  17. Effect of soft-hard segment content on properties of palm oil polyol based shape memory polyurethane

    Science.gov (United States)

    Darman, Amina; Ali, Ernie Suzana; Zubir, Syazana Ahmad

    2017-07-01

    Shape memory polymers (SMP) are smart materials with the ability of changing shape when subjected to external stimuli. In this work, the shape memory polyurethane (SMPU) has been synthesized via two step bulk polymerization method by replacing up to 40% molar ratio of petroleum-based polyol using palm oil-based polyols (POP). This effort was done with the purpose of reducing the usage of petroleum-based polyol due to environmental awareness. The main objective is to investigate the effects of different polyol/isocyanate/1,4-butanediol molar ratio in relation to soft-hard segment content towards the mechanical and shape memory properties of the resulting SMPU. The mechanical properties were improved with POP addition and optimum performance of tensile properties were obtained within 35 to 40% of hard segment content. Tensile strength increased with increasing POP content but after 40% of hard segment content, the properties decreased. On the other hand, the modulus significantly reduced with an increase of hard segment content. Crystallinity also decreased with decreasing of polycaprolactone diol (PCL) content as more POP content was added. Shape memory properties of PU 165 is better than PU 154 in terms of the ability to return to its original shape since all of PU 165 samples showed 100% recovery. In general, the addition of palm oil-based polyol showed improvement in mechanical and shape memory properties as compared to pristine SMPU.

  18. Fermentation of xylose to ethanol by genetically modified enteric bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Tolan, J.S.

    1987-01-01

    This thesis describes the fermentation of D-xylose by wild type and recombinant Klebsiella planticola ATCC 33531 and Erwinia chrysanthemi B374. The recombinant strains bear multi-copy plasmids containing the pdc gene inserted from Zymomonas mobilis. Expression of the gene in K. planticola markedly increased the yield of ethanol, up to 1.3 mole/mole xylose, or 25.1 g/L. Concurrently, there were significant decreases in the yields of formation acetate, lactate, and butanediol. Transconjugant Klebsiella grew almost as fast as the wild type and tolerated up to 4% ethanol. The plasmid was retained by the cells during at least one batch culture, even in the absence of selective pressure by antibiotics to maintain the plasmid. The cells produced 31.6 g/L ethanol from 79.6 g/L of a D-glucose-D-xylose-L-arabinose mixture designed to simulate hydrolyzed hemicellulose. The physiology of the wild type K. planticola is described in more detail than in the original report of its isolation. E. chrysanthemi PDC transconjugants also produced ethanol in high yield (up to 1.45 mole/mole xylose). However, transconjugant E. chrysanthemi grew only 1/4 as rapidly as the wild type and tolerated only 2% ethanol. The plasmid PZM15 apparently exhibits pleiotropic effects when inserted into K. planticola and into E. chrysanthemi.

  19. Enhanced performance of the microalga Chlorella sorokiniana remotely induced by the plant growth-promoting bacteria Azospirillum brasilense and Bacillus pumilus.

    Science.gov (United States)

    Amavizca, Edgar; Bashan, Yoav; Ryu, Choong-Min; Farag, Mohamed A; Bebout, Brad M; de-Bashan, Luz E

    2017-02-01

    Remote effects (occurring without physical contact) of two plant growth-promoting bacteria (PGPB) Azospirillum brasilense Cd and Bacilus pumilus ES4 on growth of the green microalga Chlorella sorokiniana UTEX 2714 were studied. The two PGPB remotely enhanced the growth of the microalga, up to six-fold, and its cell volume by about three-fold. In addition to phenotypic changes, both bacteria remotely induced increases in the amounts of total lipids, total carbohydrates, and chlorophyll a in the cells of the microalga, indicating an alteration of the microalga's physiology. The two bacteria produced large amounts of volatile compounds, including CO2, and the known plant growth-promoting volatile 2,3-butanediol and acetoin. Several other volatiles having biological functions in other organisms, as well as numerous volatile compounds with undefined biological roles, were detected. Together, these bacteria-derived volatiles can positively affect growth and metabolic parameters in green microalgae without physical attachment of the bacteria to the microalgae. This is a new paradigm on how PGPB promote growth of microalgae which may serve to improve performance of Chlorella spp. for biotechnological applications.

  20. Production of 3-hydroxypropionate homopolymer and poly(3-hydroxypropionate-co-4-hydroxybutyrate) copolymer by recombinant Escherichia coli.

    Science.gov (United States)

    Zhou, Qin; Shi, Zhen-Yu; Meng, De-Chuan; Wu, Qiong; Chen, Jin-Chun; Chen, Guo-Qiang

    2011-11-01

    Conversion of 3-hydroxypropionate (3HP) from 1,3-propanediol (PDO) was improved by expressing dehydratase gene (dhaT) and aldehyde dehydrogenase gene (aldD) of Pseudomonas putida KT2442 under the promoter of phaCAB operon from Ralstonia eutropha H16. Expression of these genes in Aeromonas hydrophila 4AK4 produced up to 21 g/L 3HP in a fermentation process. To synthesize homopolymer poly(3-hydroxypropionate) (P3HP), and copolymer poly(3-hydroxypropionate-co-3-hydroxybutyrate) (P3HP4HB), dhaT and aldD were expressed in E. coli together with the phaC1 gene encoding polyhydroxyalkanoate (PHA) synthase gene of Ralstonia eutropha, and pcs' gene encoding the ACS domain of the tri-functional propionyl-CoA ligase (PCS) of Chloroflexus aurantiacus. Up to 92 wt% P3HP and 42 wt% P3HP4HB were produced by the recombinant Escherichia coli grown on PDO and a mixture of PDO+1,4-butanediol (BD), respectively. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. Synthesis of graphene oxide grafted poly(lactic acid) with palladium nanoparticles and its application to serotonin sensing

    Energy Technology Data Exchange (ETDEWEB)

    Han, Hyoung Soon; You, Jung-Min; Jeong, Haesang; Jeon, Seungwon, E-mail: swjeon3380@naver.com

    2013-11-01

    Graphene oxide (GO) has treated with methylene diphenyl diisocyanate (MDI) and subsequent 1,4-butanediol (BD) to create an anchoring OH site on the surface of GO (GO-MDI-OH). The OH groups of GO-MDI-OH were the initiators of the polymerization of poly(lactic acid) (PLA). The subsequent GO-g-PLA was synthesized by the polymerization reaction in the presence of GO-MDI-OH and PLA. The synthesized materials were characterized via {sup 1}H-NMR, Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), thermal analysis (differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA)). The surface morphologies and degree of dispersions at G-g-PLA-metals were observed using a field emission scanning electron microscope (FE-SEM) and a transmission electron microscopy (TEM). The electrical conductivity of G-g-PLA-Pd was largely enhanced compared with those of GO and GO-g-PLA. G-g-PLA-Pd was used for the electrochemical detection of serotonin. Electrocatalytic activities were verified from the cyclic voltammetry (CV) and amperometric response in a 0.1 M phosphate buffer solution (PBS). A significantly higher concentration range (0.1–100.0 μM) and a lower detection limit (8.0 × 10{sup −8} M, where s/n = 3) were found at the G-g-PLA-Pd modified glassy carbon electrode (GCE).

  2. {sup 13}C solution NMR spectra of poly(ether)urethanes. Technical memorandum

    Energy Technology Data Exchange (ETDEWEB)

    Hiltz, J.A

    2002-11-15

    The {sup 13}C solution nuclear magnetic resonance (NMR) spectra of the 15 poly(ether)urethanes are presented. The poly(urethane)s were prepared using one of two diisocyanates, either methylene diphenyl diisocyanate (MDI) or hexamethylene diisocyanate (HDI), one of five poly(ether glycol)s, poly(tetramethylene ether glycol) of molecular weight 650, 1000, or 1400, or poly(ethylene glycol) of molecular weight 600 or 1000, and one of three chain extenders, 1,4-butanediol, 2,2-dimethyl-1,3-propanediol, or diethylene glycol. These polymers were prepared as part of a modelling study to determine if Group Contribution Theory and Group Interaction Modelling could be used to predict dynamic mechanical properties of poly(ether)urethanes on the basis of the structural fragments in the polymers. The chemical shifts of the unique carbons in each of the poly(urethane)s are assigned. They can be used to unambiguously identify the diisocyanate/diol/poly(ether glycol) used to prepare the various polyurethanes. For some compounds the spectra show resonances for terminal hydroxyl substituted carbons. These could provide a method, under the right experimental conditions, to compare molecular weights of batches of the same polymer. (author)

  3. Impact of a Microbial Cocktail Used as a Starter Culture on Cocoa Fermentation and Chocolate Flavor

    Directory of Open Access Journals (Sweden)

    Igor Magalhães da Veiga Moreira

    2017-05-01

    Full Text Available Chocolate production suffered a vast impact with the emergence of the “witches’ broom” disease in cocoa plants. To recover cocoa production, many disease-resistant hybrid plants have been developed. However, some different cocoa hybrids produce cocoa beans that generate chocolate with variable quality. Fermentation of cocoa beans is a microbiological process that can be applied for the production of chocolate flavor precursors, leading to overcoming the problem of variable chocolate quality. The aim of this work was to use a cocktail of microorganisms as a starter culture on the fermentation of the ripe cocoa pods from PH15 cocoa hybrid, and evaluate its influence on the microbial communities present on the fermentative process on the compounds involved during the fermentation, and to perform the chocolate sensorial characterization. According to the results obtained, different volatile compounds were identified in fermented beans and in the chocolate produced. Bitterness was the dominant taste found in non-inoculated chocolate, while chocolate made with inoculated beans showed bitter, sweet, and cocoa tastes. 2,3-Butanediol and 2,3-dimethylpyrazine were considered as volatile compounds making the difference on the flavor of both chocolates. Saccharomyces cerevisiae UFLA CCMA 0200, Lactobacillus plantarum CCMA 0238, and Acetobacter pasteurianus CCMA 0241 are proposed as starter cultures for cocoa fermentation.

  4. Impact of a Microbial Cocktail Used as a Starter Culture on Cocoa Fermentation and Chocolate Flavor.

    Science.gov (United States)

    Magalhães da Veiga Moreira, Igor; de Figueiredo Vilela, Leonardo; da Cruz Pedroso Miguel, Maria Gabriela; Santos, Cledir; Lima, Nelson; Freitas Schwan, Rosane

    2017-05-09

    Chocolate production suffered a vast impact with the emergence of the "witches' broom" disease in cocoa plants. To recover cocoa production, many disease-resistant hybrid plants have been developed. However, some different cocoa hybrids produce cocoa beans that generate chocolate with variable quality. Fermentation of cocoa beans is a microbiological process that can be applied for the production of chocolate flavor precursors, leading to overcoming the problem of variable chocolate quality. The aim of this work was to use a cocktail of microorganisms as a starter culture on the fermentation of the ripe cocoa pods from PH15 cocoa hybrid, and evaluate its influence on the microbial communities present on the fermentative process on the compounds involved during the fermentation, and to perform the chocolate sensorial characterization. According to the results obtained, different volatile compounds were identified in fermented beans and in the chocolate produced. Bitterness was the dominant taste found in non-inoculated chocolate, while chocolate made with inoculated beans showed bitter, sweet, and cocoa tastes. 2,3-Butanediol and 2,3-dimethylpyrazine were considered as volatile compounds making the difference on the flavor of both chocolates. Saccharomyces cerevisiae UFLA CCMA 0200, Lactobacillus plantarum CCMA 0238, and Acetobacter pasteurianus CCMA 0241 are proposed as starter cultures for cocoa fermentation.

  5. Exploring mild enzymatic sustainable routes for the synthesis of bio-degradable aromatic-aliphatic oligoesters.

    Science.gov (United States)

    Pellis, Alessandro; Guarneri, Alice; Brandauer, Martin; Acero, Enrique Herrero; Peerlings, Henricus; Gardossi, Lucia; Guebitz, Georg M

    2016-05-01

    The application of Candida antarctica lipase B in enzyme-catalyzed synthesis of aromatic-aliphatic oligoesters is here reported. The aim of the present study is to systematically investigate the most favorable conditions for the enzyme catalyzed synthesis of aromatic-aliphatic oligomers using commercially available monomers. Reaction conditions and enzyme selectivity for polymerization of various commercially available monomers were considered using different inactivated/activated aromatic monomers combined with linear polyols ranging from C2 to C12 . The effect of various reaction solvents in enzymatic polymerization was assessed and toluene allowed to achieve the highest conversions for the reaction of dimethyl isophthalate with 1,4-butanediol and with 1,10-decanediol (88 and 87% monomer conversion respectively). Mw as high as 1512 Da was obtained from the reaction of dimethyl isophthalate with 1,10-decanediol. The obtained oligomers have potential applications as raw materials in personal and home care formulations, for the production of aliphatic-aromatic block co-polymers or can be further functionalized with various moieties for a subsequent photo- or radical polymerization. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Comparison of analytical protein separation characteristics for three amine-based capillary-channeled polymer (C-CP) stationary phases.

    Science.gov (United States)

    Jiang, Liuwei; Marcus, R Kenneth

    2016-02-01

    Capillary-channeled polymer (C-CP) fiber stationary phases are finding utility in the realms of protein analytics as well as downstream processing. We have recently described the modification of poly(ethylene terephthalate) (PET) C-CP fibers to affect amine-rich phases for the weak anion-exchange (WAX) separation of proteins. Polyethylenimine (PEI) is covalently coupled to the PET surface, with subsequent cross-linking imparted by treatment with 1,4-butanediol diglycidyl ether (BUDGE). These modifications yield vastly improved dynamic binding capacities over the unmodified fibers. We have also previously employed native (unmodified) nylon 6 C-CP fibers as weak anion/cation-exchange (mixed-mode) and hydrophobic interaction chromatography (HIC) phases for protein separations. Polyamide, nylon 6, consists of amide groups along the polymer backbone, with primary amines and carboxylic acid end groups. The analytical separation characteristics of these three amine-based C-CP fiber phases are compared here. Each of the C-CP fiber columns in this study was shown to be able to separate a bovine serum albumin/hemoglobin/lysozyme mixture at high mobile phase linear velocity (∼70 mm s(-1)) but with different elution characteristics. These differences reflect the types of protein-surface interactions that are occurring, based on the active group composition of the fiber surfaces. This study provides important fundamental understanding for the development of surface-modified C-CP fiber columns for protein separation.

  7. A novel approach to improve poly-γ-glutamic acid production by NADPH Regeneration in Bacillus licheniformis WX-02.

    Science.gov (United States)

    Cai, Dongbo; He, Penghui; Lu, Xingcheng; Zhu, Chengjun; Zhu, Jiang; Zhan, Yangyang; Wang, Qin; Wen, Zhiyou; Chen, Shouwen

    2017-02-23

    Poly-γ-glutamic acid (γ-PGA) is an important biochemical product with a variety of applications. This work reports a novel approach to improve γ-PGA through over expression of key enzymes in cofactor NADPH generating process for NADPH pool. Six genes encoding the key enzymes in NADPH generation were over-expressed in the γ-PGA producing strain B. licheniformis WX-02. Among various recombinants, the strain over-expressing zwf gene (coding for glucose-6-phosphate dehydrogenase), WX-zwf, produced the highest γ-PGA concentration (9.13 g/L), 35% improvement compared to the control strain WX-pHY300. However, the growth rates and glucose uptake rates of the mutant WX-zwf were decreased. The transcriptional levels of the genes pgsB and pgsC responsible for γ-PGA biosynthesis were increased by 8.21- and 5.26-fold, respectively. The Zwf activity of the zwf over expression strain increased by 9.28-fold, which led to the improvement of the NADPH generation, and decrease of accumulation of by-products acetoin and 2,3-butanediol. Collectively, these results demonstrated that NADPH generation via over-expression of Zwf is as an effective strategy to improve the γ-PGA production in B. licheniformis.

  8. Reducing of on Polymerization Shrinkage by Application of UV Curable Dental Restorative Composites

    Directory of Open Access Journals (Sweden)

    Świderska Jolanta

    2014-09-01

    Full Text Available This manuscript describes dental compositions contain in-organic fillers, multifunctional methacrylates and photoinitiators. The main problem by application and UV curing process is the shrinkage of photoreactive dental materials during and after UV curing process. Total shrinkage of UV curable dental composites is a phenomenon of polymerization shrinkage, typical behavior for multifunctional methacrylates during polymerization process. The important factors by curing of dental composites are: kind and concentration of used methacrylates, their functionality, double bond concentration, kind and concentration of added photoinitiator and UV dose. They are investigated UV-curable dental compositions based on 2,2-bis-[4-(2-hydroxy-3-methacryxloyloxypropylphenyl]propane (Bis-GMA and containing such multifunctional monomers as 1,3-butanediol dimethacrylate (1,3-BDDMA, diethylene glycol dimethacrylate (DEGDMA, tetraethylene glycol dimethacrylate (T3EGDMA, trimethylolpropane trimethacrylate (TMPTMA, polyethylene glycol 200 dimethacrylate (PEG200DA. Reduction of polymerization shrinkage of dental compositions is at the moment a major problem by dental technology.

  9. Dynamical mechanical analysis of photocrosslinked hyperbranched urethane acrylates

    Directory of Open Access Journals (Sweden)

    BRANKO DUNJIC

    2004-06-01

    Full Text Available A series of acrylate functionalized samples based on hyperbranched hydroxy-terminated polyesters with different molecular weights and different degrees of acrylation were synthesized. The obtained urethane acrylates were slightly yellow viscose liquids. Their composition was characterized by FTIR and 1H-NMR spectroscopy and their molecular weights were measured by GPC. All the synthesized samples were diluted with 25 wt.% 1,4-butanediol dimethacrylate (BDDM. The rheological properties of the uncured samples and the dynamic mechanical properties of the UV cured samples were examined. All the samples exhibit Newtonian behavior, which indicates the absence of physical entanglements in these polymers. The viscosity increases with increasing number of acrylic groups per molecule. The glass transition temperature of the UV cured samples increases with increasing the number of acrylic groups per molecule. The value of the storage modulus in the rubber-elastic plateau and the cross-link density increase with increasing number of acrylic groups per molecule. The formed networks are inhomogeneous and the residual unsaturation is the highest in the samples with the largest number of acrylic groups per molecule.

  10. Highly stable phase change material emulsions fabricated by interfacial assembly of amphiphilic block copolymers during phase inversion.

    Science.gov (United States)

    Park, Hanhee; Han, Dong Wan; Kim, Jin Woong

    2015-03-10

    This study introduced a robust and promising approach to fabricate highly stable phase change material (PCM) emulsions consisting of n-tetradecane as a dispersed phase and a mixture of meso-2,3-butanediol (m-BDO) and water as a continuous phase. We showed that amphiphilic poly(ethylene oxide)-b-poly(ε-caprolactone) block copolymers assembled to form a flexible but tough polymer membrane at the interface during phase inversion from water-in-oil emulsion to oil-in-water emulsion, thus remarkably improving the emulsion stability. Although the incorporation of m-BDO into the emulsion lowered the phase changing enthalpy, it provided a useful means to elevate the melting temperature of the emulsions near to 15 °C. Interestingly, supercooling was commonly observed in our PCM emulsions. We attributed this to the fact that the PCM molecules confined in submicron-scale droplets could not effectively nucleate to grow molecular crystals. Moreover, the presence of m-BDO in the continuous phase rather dominated the heat emission of the emulsion system during freezing, which made the supercooling more favorable.

  11. A study of the methylene/perfluormethylene selectivity of porous polymer monolithic stationary phases exhibiting different fluorous/hydrophobic content.

    Science.gov (United States)

    Xu, Zhenpo; Oleschuk, Richard D

    2014-02-14

    Porous polymer monolithic columns are prepared from a variety of monomers and cross-linkers and can be customized to exhibit different selectivities for separate analyte classes. The composition of the monolith can be precisely controlled by selecting different monomers and or cross-linker ratios. In this work monoliths exhibiting both fluorous and hydrophobic character were prepared using butyl methacrylate and its fluorous analogue (monomer) and 1,3-butanediol diacrylate and its fluorous analogue (cross-linker) in different ratios. The selectivity of the monoliths was probed using capillary electrochromatography with several fluorous and alkyl benzene analytes. Hydrophobic stationary phases exhibited greater methylene selectivity ( [Formula: see text] ) while those with increasing fluorous character show enhanced pefluoromethylene selectivity ( [Formula: see text] ). The Gibbs free energy change associated with the sorption of the analytes on each stationary phase composition can be calculated from migration times (i.e. capacity factor) for the addition of an individual -CF2- or -CH2- moiety. Furthermore, the Gibbs free energy change associated with a single -CF2- or -CH2- moiety (analyte) interacting with an individual -CF2- or -CH2- (stationary phase) can also be estimated by plotting fluorous column composition against [Formula: see text] . Furthermore [Formula: see text] and [Formula: see text] can be plotted versus H2O percentage in mobile phase, and a new concept, hypothetical water percentage (HWP) is proposed to evaluate the hydrophobicity/fluorophilicity of a stationary phase. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Synthesis and properties of aqueous polyurethane dispersions: Influence of molecular weight of polyethylene glycol

    Energy Technology Data Exchange (ETDEWEB)

    Mumtaz, Fatima; Zuber, Mohammad; Zia, Khalid Mahmood [Government College University, Faisalabad (Pakistan); Jamil, Tahir [University of the Punjab, Lahore (Pakistan); Hussain, Rizwan [National Engineering and Scientific Commission (NESCOM), Islamabad (Pakistan)

    2013-12-15

    Aqueous polyurethane dispersions (PUDs) have recently emerged as important alternatives to their solvent-based counterparts for various applications due to increasing health and environmental awareness. A series of aqueous polyurethane dispersions containing carboxylate anion as hydrophilic pendant groups were synthesized through step growth polymerization reaction using hexamethylene diisocyanate (HDI), 1,4-butanediol (1,4-BDO), dimethylol propionic acid (DMPA) and polyethylene glycol (PEG) of different molecular weight. Effect of PEG molecular weight was investigated on molecular structure, contact angle measurement, and physical and adhesive properties of PU emulsions. Fourier transform infrared spectroscopy (FT-IR) was used to check the completion of polymerization reaction. Contact angle measurement indicated that the hydrophilicity of polymer increases by increasing molecular weight of PEG with a corresponding decrease in contact angle. Results of T-peel test showed a decrease in peel strength by increasing molecular weight of PEG. Moreover, solid contents%, drying time and storage stability suggested fast drying properties and greater stability of aqueous PU dispersions.

  13. Biological relevance of volatile organic compounds emitted during the pathogenic interactions between apple plants and Erwinia amylovora.

    Science.gov (United States)

    Cellini, Antonio; Buriani, Giampaolo; Rocchi, Lorenzo; Rondelli, Elena; Savioli, Stefano; Rodriguez Estrada, Maria T; Cristescu, Simona M; Costa, Guglielmo; Spinelli, Francesco

    2016-11-15

    Volatile organic compounds emitted during the infection of apple (Malus pumila var. domestica) plants by Erwinia amylovora or Pseudomonas syringae pv. syringae were studied by gas chromatography-mass spectrometry and proton transfer reaction-mass spectrometry, and used to treat uninfected plants. Infected plants showed a disease-specific emission of volatile organic compounds, including several bio-active compounds, such as hexenal isomers and 2,3-butanediol. Leaf growth promotion and a higher resistance to the pathogen, expressed as a lower bacterial growth and migration in plant tissues, were detected in plants exposed to volatile compounds from E. amylovora-infected plants. Transcriptional analysis revealed the activation of salicylic acid synthesis and signal transduction in healthy plants exposed to volatiles produced by E. amylovora-infected neighbour plants. In contrast, in the same plants, salicylic acid-dependent responses were repressed after infection, whereas oxylipin metabolism was activated. These results clarify some metabolic and ecological aspects of the pathogenic adaptation of E. amylovora to its host. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  14. Exploring Network Formation of Tough and Biocompatible Thiol-yne Based Photopolymers.

    Science.gov (United States)

    Oesterreicher, Andreas; Gorsche, Christian; Ayalur-Karunakaran, Santhosh; Moser, Andreas; Edler, Matthias; Pinter, Gerald; Schlögl, Sandra; Liska, Robert; Griesser, Thomas

    2016-10-01

    This work deals with the in-depth investigation of thiol-yne based network formation and its effect on thermomechanical properties and impact strength. The results show that the bifunctional alkyne monomer di(but-1-yne-4-yl)carbonate (DBC) provides significantly lower cytotoxicity than the comparable acrylate, 1,4-butanediol diacrylate (BDA). Real-time near infrared photorheology measurements reveal that gel formation is shifted to higher conversions for DBC/thiol resins leading to lower shrinkage stress and higher overall monomer conversion than BDA. Glass transition temperature (Tg ), shrinkage stress, as well as network density determined by double quantum solid state NMR, increase proportionally with the thiol functionality. Most importantly, highly cross-linked DBC/dipentaerythritol hexa(3-mercaptopropionate) networks (Tg ≈ 61 °C) provide a 5.3 times higher impact strength than BDA, which is explained by the unique network homogeneity of thiol-yne photopolymers. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Research on Pork Jerky Obtained Through Fermentation with Pediococcus acidilactici

    Directory of Open Access Journals (Sweden)

    Zhao Xingxiu

    2016-03-01

    Full Text Available Pediococcus acidilactici was used to ferment fresh pork. After fermentation, the pork jerky was subjected to sensory evaluation and the levels of pH, free amino acids, and volatile compounds were measured. The results showed that the fermented pork jerky had a better sensory evaluation score (score: 93.2, lower pH value (3.54, and more free amino acids (39.24 mg/100 g. Furthermore, in the fermented pork jerky, the content of three acids (18.552% was high, which lowered the pH of the pork jerky and inhibited growth of pathogens. Moreover, some new compounds produced, including 3-hydroxy-2-butanone (49.095%, 2,3-butanediol (2.790%, 2-ethyl-1-hexanol (2.400%, oxalic acid isobutyl hexyl ester (2.280%, phenylethyl alcohol (0.953%, and eucalyptol (0.659%, contributed to the flavour of pork jerky. Overall, our results demonstrated that P. acidilactici can be used for the production as well as improvement of the quality and flavour of fermented pork jerky.

  16. Optimization of Bicomponent Electrospun Fibers for Therapeutic Use: Post-Treatments to Improve Chemical and Biological Stability

    Directory of Open Access Journals (Sweden)

    Antonio Papa

    2017-10-01

    Full Text Available Bicomponent electrospun nanofibers based on the combination of synthetic (i.e., aliphatic polyesters such as polycaprolactone (PCL and natural proteins (i.e., gelatin have been extensively investigated as temporary platforms to instruct cells by the release of molecular/pharmaceutical signals for the regeneration of several tissues. Here, water soluble proteins (i.e., gelatin, strictly embedded to PCL, act as carriers of bioactive molecules, thus improving bioavailability and supporting cell activities during in vitro regeneration. However, these proteins are rapidly digested by enzymes, locally produced by many different cell types, both in vitro and in vivo, with significant drawbacks in the control of molecular release. Hence, we have investigated three post-processing strategies based on the use of different crosslinking agents—(1-ethyl-3-(3-dimethylaminopropylcarbodiimide hydrochloride (EDC, glyceraldehyde (GC, and 1,4-butanediol diglycidyl ether (BDDGE—to delay the dissolution time of gelatin macromolecules from bicomponent fibers. All of the qualitative (i.e., SEM, TGA and quantitative (i.e., Trinitrobenzene sulfonate (TNBS and bicinchoninic acid (BCA assays morphological/chemical analyses as well as biocompatibility assays indicate that EDC crosslinking improves the chemical stability of bicomponent fibers at 37 °C and provides a more efficient encapsulation and controlled sustained release of drug, thus resulting in the best post-treatment to design bio-inspired fibrous platforms for the extended in vitro release of drugs.

  17. Comparison of monolithic silica and polymethacrylate capillary columns for LC.

    Science.gov (United States)

    Moravcová, Dana; Jandera, Pavel; Urban, Jiri; Planeta, Josef

    2004-07-01

    Organic polymer monolithic capillary columns were prepared in fused-silica capillaries by radical co-polymerization of ethylene dimethacrylate and butyl methacrylate monomers with azobisisobutyronitrile as initiator of the polymerization reaction in the presence of various amounts of porogenic solvent mixtures and different concentration ratios of monomers and 1-propanol, 1,4-butanediol, and water. The chromatographic properties of the organic polymer monolithic columns were compared with those of commercial silica-based particulate and monolithic capillary and analytical HPLC columns. The tests included the determination of H-u curves, column permeabilities, pore distribution by inversed-SEC measurements, methylene and polar selectivities, and polar interactions with naphthalenesulphonic acid test samples. Organic polymer monolithic capillary columns show similar retention behaviour to chemically bonded alkyl silica columns for compounds with different polarities characterized by interaction indices, Ix, but have lower methylene selectivities and do not show polar interactions with sulphonic acids. The commercial capillary and analytical silica gel-based monolithic columns showed similar selectivities and provided symmetrical peaks, indicating no significant surface heterogeneities. To allow accurate characterization of the properties of capillary monolithic columns, the experimental data should be corrected for extra-column contributions. With 0.3 mm ID capillary columns, corrections for extra-column volume contributions are sufficient, but to obtain true information on the efficiency of 0.1 mm ID capillary columns, the experimental bandwidths should be corrected for extra-column contributions to peak broadening.

  18. Comparative performance of collagen nanofibers electrospun from different solvents and stabilized by different crosslinkers.

    Science.gov (United States)

    Fiorani, Andrea; Gualandi, Chiara; Panseri, Silvia; Montesi, Monica; Marcacci, Maurilio; Focarete, Maria Letizia; Bigi, Adriana

    2014-10-01

    Collagen electrospun scaffolds well reproduce the structure of the extracellular matrix (ECM) of natural tissues by coupling high biomimetism of the biological material with the fibrous morphology of the protein. Structural properties of collagen electrospun fibers are still a debated subject and there are conflicting reports in the literature addressing the presence of ultrastructure of collagen in electrospun fibers. In this work collagen type I was successfully electrospun from two different solvents, trifluoroethanol (TFE) and dilute acetic acid (AcOH). Characterization of collagen fibers was performed by means of SEM, ATR-IR, Circular Dichroism and WAXD. We demonstrated that collagen fibers contained a very low amount of triple helix with respect to pristine collagen (18 and 16% in fibers electrospun from AcOH and TFE, respectively) and that triple helix denaturation occurred during polymer dissolution. Collagen scaffolds were crosslinked by using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), a commonly employed crosslinker for electrospun collagen, and 1,4-butanediol diglycidyl ether (BDDGE), that was tested for the first time in this work as crosslinking agent for collagen in the form of electrospun fibers. We demonstrated that BDDGE successfully crosslinked collagen and preserved at the same time the scaffold fibrous morphology, while scaffolds crosslinked with EDC completely lost their porous structure. Mesenchymal stem cell experiments demonstrated that collagen scaffolds crosslinked with BDDGE are biocompatible and support cell attachment.

  19. Acetoin catabolism and acetylbutanediol formation by Bacillus pumilus in a chemically defined medium.

    Science.gov (United States)

    Xiao, Zijun; Ma, Cuiqing; Xu, Ping; Lu, Jian R

    2009-05-20

    Most low molecular diols are highly water-soluble, hygroscopic, and reactive with many organic compounds. In the past decades, microbial research to produce diols, e.g. 1,3-propanediol and 2,3-butanediol, were considerably expanded due to their versatile usages especially in polymer synthesis and as possible alternatives to fossil based feedstocks from the bioconversion of renewable natural resources. This study aimed to provide a new way for bacterial production of an acetylated diol, i.e. acetylbutanediol (ABD, 3,4-dihydroxy-3-methylpentan-2-one), by acetoin metabolism. When Bacillus pumilus ATCC 14884 was aerobically cultured in a chemically defined medium with acetoin as the sole carbon and energy source, ABD was produced and identified by gas chromatography--chemical ionization mass spectrometry and NMR spectroscopy. Although the key enzyme leading to ABD from acetoin has not been identified yet at this stage, this study proposed a new metabolic pathawy to produce ABD in vivo from using renewable resources--in this case acetoin, which could be reproduced from glucose in this study--making it the first facility in the world to prepare this new bio-based diol product.

  20. Acetoin catabolism and acetylbutanediol formation by Bacillus pumilus in a chemically defined medium.

    Directory of Open Access Journals (Sweden)

    Zijun Xiao

    Full Text Available BACKGROUND: Most low molecular diols are highly water-soluble, hygroscopic, and reactive with many organic compounds. In the past decades, microbial research to produce diols, e.g. 1,3-propanediol and 2,3-butanediol, were considerably expanded due to their versatile usages especially in polymer synthesis and as possible alternatives to fossil based feedstocks from the bioconversion of renewable natural resources. This study aimed to provide a new way for bacterial production of an acetylated diol, i.e. acetylbutanediol (ABD, 3,4-dihydroxy-3-methylpentan-2-one, by acetoin metabolism. METHODOLOGY/PRINCIPAL FINDINGS: When Bacillus pumilus ATCC 14884 was aerobically cultured in a chemically defined medium with acetoin as the sole carbon and energy source, ABD was produced and identified by gas chromatography--chemical ionization mass spectrometry and NMR spectroscopy. CONCLUSIONS/SIGNIFICANCE: Although the key enzyme leading to ABD from acetoin has not been identified yet at this stage, this study proposed a new metabolic pathawy to produce ABD in vivo from using renewable resources--in this case acetoin, which could be reproduced from glucose in this study--making it the first facility in the world to prepare this new bio-based diol product.

  1. Reducing activity, glucose metabolism and acid tolerance response of Bacillus cereus grown at various pH and oxydo-reduction potential levels.

    Science.gov (United States)

    Le Lay, Julien; Bahloul, Halim; Sérino, Sylvie; Jobin, Michel; Schmitt, Philippe

    2015-04-01

    Bacillus cereus is a major foodborne bacterial pathogen able to survive a large number of physical-chemical stresses. B. cereus encounters different pH and redox potential (Eh7) levels during its passage through the gastrointestinal tract. Analysis of the combined influence of pH and redox stresses on B. cereus F4430/73 physiology found that B. cereus F4430/73 growth at pH 7.0 at 37 °C had strong reducing capacities, with a total change of 315 mV from an initial redox value of +214 ± 17 mV. The combination of low Eh7 and low pH led to a drastic reduction of growth parameters compared to oxidative Eh7 and neutral pH. Metabolic analysis showed that low pH significantly modifies glucose fermentative metabolism, with changes including decreased production of acid metabolite (acetate, lactate, formate) and increased production of 2,3-butanediol. Low Eh7 slightly enhanced the acid-tolerance response of B. cereus whereas low pH pre-adaptation led to thermal stress cross-protection. These results highlight new mechanisms that bring fresh insight into B. cereus pH and redox stress adaptations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Evaluation report on the development of polymeric material from renewable resource using biocatalyst; Seitai shokubai wo riyoshita saisei kano shigen kara no kobunshi sozai no kaihatsu hyoka hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    The project aims to develop a biocatalyst-assisted synthesizing method for efficiently manufacturing sugar containing polymers and polylactic acids which generate less environmental impact. Methods were developed using the ALP-901 originating in actinomycetes for changing esterification-shy isopropylidene glucose into vinyladipic ester and for esterifying arbutin. A study was made of the polymerization of sugar ester monomers, and a polymer with a molecular weight of scores of thousands was obtained. The biodegradability of sugar containing polymers was confirmed. Using an enzyme, a polymer with a molecular weight of 1200 was obtained. Using a lipase derived from psudomonas cepacia, a polylactic acid was obtained from lactide. A high-function polylactic acid was obtained in a reaction between methyl lactate and divinyladipate. In a reaction between butanediol and lactide, several lactic oligomers different in molecular weight were synthesized, which were then brought into reaction with divinylcarboxylic acid in the presence of an enzyme for the production of polymerizable lactic oligomers. Similarly, polymerizable lactic oligomer derivatives were obtained from glucose and lactide. The oligomers and derivatives were brought into polymerization in the presence of a radical polymerization initiator for the production of polymeric gels, respectively. (NEDO)

  3. Fiscal 2000 achievement report on the development of polymeric material from renewable resource using biocatalyst; 2000 nendo seitai shokubai wo riyoshita saisei kano shigen kara no kobunshi sozai no kaihatsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    The project aims to develop a biocatalyst-assisted synthesizing method for efficiently manufacturing sugar containing polymers and polylactic acids which generate less environmental impact. The ALP-901 derived from actinomycetes operates best with 5% water content, and remains free of hydrolytic effect even when the rate rises to 20%, and catalyzes transesterification only. The esterification activity of bioprase rose remarkably upon addition of water. A polymer with a molecular weight of scores of thousands was obtained in the polymerization of sugar ester monomers. A sugar undecylenate with a double bond at an end was successfully polymerized. The sugar containing polymer exhibited excellent biodegradability. In a reaction of butanediol and lactide, several types of lactic oligomers different in molecular weight were synthesized. The oligomers were caused to react with divinylcarboxylic acid in the presence of an enzyme, and a polymerizable lactic oligomer was obtained. Furthermore, in a reaction between glucose and lactide, several lactic oligomer derivatives were synthesized, different in molecular weight. In a reaction of the derivatives and divinylcarboxylic acid with an enzyme added thereto, a polymerizable lactic oligomer derivative was obtained, which was brought into polymerization in the presence of a radical polymerization initiator for the production of a high molecular weight gel. (NEDO)

  4. New agar microspheres for the separation and purification of natural products.

    Science.gov (United States)

    Ge, Chunling; Hu, Yu; Zhang, Fan; Lv, Yongqin; Tan, Tianwei

    2014-11-01

    A new type of agar chromatography media has been prepared with a yield over 80% using a water-in-oil emulsion technique. These microspheres have regular spherical shapes and particle diameters in the range 40-165 μm (average ∼90 μm). Cross-linking of the resulting agar microspheres with epichlorohydrin and 1,4-butanediol diglycidyl ether enhanced their mechanical and thermal stability. The alkaline conditions used during the cross-linking reaction also decreased the content of ionized sulfate groups of the polysaccharide, thus reducing the nonspecific adsorption of positively charged molecules. The cross-linked agar microspheres were functionalized with (i) branched poly(ethyleneimine) to obtain a stationary phase useful for the separation of proteins in an anion-exchange mode and (ii) with poly-β-cyclodextrin enabling direct isolation and purification of puerarin from a crude extract of Radix puerariae. Using a 23.5 mL column loaded with 20 mg extract (0.85 mg/mL gel), puerarin with a purity of 96% was recovered with a yield of 86%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Sensitive determination of parabens in human urine and serum using methacrylate monoliths and reversed-phase capillary liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Carrasco-Correa, Enrique Javier; Vela-Soria, Fernando; Ballesteros, Oscar; Ramis-Ramos, Guillermo; Herrero-Martínez, José Manuel

    2015-01-30

    A method for the determination of parabens in human urine and serum by capillary liquid chromatography (cLC) with UV-Vis and mass spectrometry (MS) detection using methacrylate ester-based monolithic columns has been developed. The influence of composition of polymerization mixture was studied. The optimum monolith was obtained with butyl methacrylate monomer at 60/40% (wt/wt) butyl methacrylate/ethylene dimethacrylate ratio and 50wt% porogens (composed of 36wt% of 1,4-butanediol, 54wt% 1-propanol and 10wt% water). Baseline resolution of analytes was achieved through a mobile phase of acetonitrile/water in gradient elution mode. Additionally, dispersive liquid-liquid microextraction (DLLME) was combined with both cLC-UV-Vis and cLC-MS to achieve the determination of parabens in human urine and serum samples with very low limits of detection. Satisfactory intra- and inter-day repeatabilities were obtained in UV-Vis and MS detection, although the latter provided lower detection limits (up to 300-fold) than the UV-Vis detection. Recoveries for the target analytes from spiked biological samples ranged from 95.2% to 106.7%. The proposed methodology for the ultra-low determination of parabens in human urine and serum samples is simple and fast, the consumption of reagents is very low, and very small samples can be analyzed. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Identification and quantification of the main organic components of vinegars by high resolution {sup 1}H NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Caligiani, A. [Dipartimento di Chimica Organica e Industriale, Universita degli Studi di Parma, Via Usberti 17A, 43100-Parma (Italy)]. E-mail: augusta.caligiani@unipr.it; Acquotti, D. [Centro Interfacolta Misure, Universita degli Studi di Parma, Via Usberti 23A, 43100-Parma (Italy); Palla, G. [Dipartimento di Chimica Organica e Industriale, Universita degli Studi di Parma, Via Usberti 17A, 43100-Parma (Italy); Bocchi, V. [Dipartimento di Chimica Organica e Industriale, Universita degli Studi di Parma, Via Usberti 17A, 43100-Parma (Italy)

    2007-02-28

    A detailed analysis of the proton high-field NMR spectra of vinegars (in particular of Italian balsamic vinegars) is reported. A large number of organic substances belonging to different classes, such as carbohydrates, alcohols, organic acids, volatile compounds and amino acids, were assigned. The possibility of quantification of the substances identified in the whole vinegar sample, without extraction or pre-concentration steps, was also tested. The data validity was demonstrated in terms of precision, accuracy, repeatability and inter-day reproducibility. The effects of the most critical experimental parameters (sample concentration, water suppression and relaxation time) on the analysis response were also discussed. {sup 1}H NMR results were compared with those obtained by traditional techniques (GC-MS, titrations), and good correlations were obtained. The results showed that {sup 1}H NMR with water suppression allows a rapid, simultaneous determination of carbohydrates (glucose and fructose), organic acids (acetic, formic, lactic, malic, citric, succinic and tartaric acids), alcohols and polyols (ethanol, acetoin, 2,3-butanediol, hydroxymethylfurfural), and volatile substances (ethyl acetate) in vinegar samples. On the contrary, the amino acid determination without sample pre-concentration was critical. The {sup 1}H NMR method proposed was applied to different samples of vinegars, allowing, in particular, the discrimination of vinegars and balsamic vinegars.

  7. Control of Mechanical Properties of Thermoplastic Polyurethane Elastomers by Restriction of Crystallization of Soft Segment

    Directory of Open Access Journals (Sweden)

    Sadaharu Nakamura

    2010-12-01

    Full Text Available Mechanical properties of thermoplastic polyurethane elastomers based on either polyether or polycarbonate (PC-glycols, 4,4’-dipheylmethane diisocyanate (1,1’-methylenebis(4-isocyanatobenzene, 1,4-butanediol, were controlled by restriction of crystallization of polymer glycols. For the polyether glycol based-polyurethane elastomers (PUEs, poly(oxytetramethylene glycol (PTMG, and PTMG incorporating dimethyl groups (PTG-X and methyl side groups (PTG-L were employed as a polymer glycol. For the PC-glycol, the randomly copolymerized PC-glycols with hexamethylene (C6 and tetramethylene (C4 units between carbonate groups with various composition ratios (C4/C6 = 0/100, 50/50, 70/30 and 90/10 were employed. The degree of microphase separation and mechanical properties of both the PUEs were investigated using differential scanning calorimetry, dynamic viscoelastic property measurements and tensile testing. Mechanical properties could be controlled by changing the molar ratio of two different monomer components.

  8. Environmentally-Friendly Synthesis of Carbonate-Type Macrodiols and Preparation of Transparent Self-Healable Thermoplastic Polyurethanes

    Directory of Open Access Journals (Sweden)

    Seon-Mi Kim

    2017-11-01

    Full Text Available Carbonate-type macrodiols synthesized by base-catalyzed polycondensation of co-diols and dimethyl carbonate as an environmentally-friendly route were subsequently utilized for the preparation of transparent and self-healable thermoplastic polyurethanes (TPUs containing a carbonate-type soft segment. Three types of macrodiols, obtained from mono, dual and triple diol-monomers for target molecular weights of 1 and 1.5 kg mol−1, were analyzed by 1H NMR integration and the OH titration value. Colorless transparent macrodiols in a liquid state at a room temperature of 20 °C were obtained, except the macrodiol from mono 1,6-hexanediol. Before TPU synthesis, macrodiols require pH neutralization to prevent gelation. TPUs synthesized by a solution pre-polymer method with 4,4′-methylene(bisphenyl isocyanate and 1,4-butanediol as a chain extender exhibited moderate molecular weights, good transparencies and robust mechanical properties. Especially, the incorporation of 3-methyl-1,5-pentanediol within carbonate-type macrodiols enhanced the transparency of the resultant TPUs by decreasing the degree of microphase separation evidenced by ATR-FTIR and DSC. Interestingly, packing density of hard segments and the degree of microphase separation determined the self-healing efficiency of TPUs, which showed good performances in the case of sourced macrodiols from triple diol-monomers.

  9. POLYURETHANE COMPOSITES AS DRUG CARRIERS:: RELEASE PATTERNS

    Directory of Open Access Journals (Sweden)

    M. V. Grigoreva

    2013-10-01

    Full Text Available Biodegradable polyurethanes attract interest of those developing composite materials for biomedical applications. One of their features is their ability to serve as carriers, or matrixes, for medicines and other bioactive compounds to produce a therapeutic effect in body through targeted and/or prolonged delivery of these compounds in the process of their controlled release from matrix. The review presents polyurethane composites as matrices for a number of drugs. The relation between structure of the composites and their degradability both in vitro and in vivo and the dependence of drug release kinetics on physicochemical properties of polyurethane matrix are highlighted. The release of drugs (cefazolin, naltrexone and piroxicam from the composites based on cross-linked polyurethanes (synthesized from laprols, Mw between 1,500 and 2,000 Da and toluylene diisocyanate demonstrated more or less the same pattern (about 10 days in vitro and three to five days in vivo. In contrast, the composites with dioxydine based on a linear polyurethanes (synthesized from oligotetramethilene glycol, Mw 1,000 Da, diphenylmethane-4,4’-diisocyanate and 1,4-butanediol retained their antimicrobial activity at least 30 days. They also showed a significantly higher breaking strength as compared to that of the composites based on cross-linked polyurethanes.

  10. Integrated bioconversion of syngas into bioethanol and biopolymers.

    Science.gov (United States)

    Lagoa-Costa, Borja; Abubackar, Haris Nalakath; Fernández-Romasanta, María; Kennes, Christian; Veiga, María C

    2017-09-01

    Syngas bioconversion is a promising method for bioethanol production, but some VFA remains at the end of fermentation. A two-stage process was set-up, including syngas fermentation as first stage under strict anaerobic conditions using C. autoethanogenum as inoculum, with syngas (CO/CO2/H2/N2, 30/10/20/40) as gaseous substrate. The second stage consisted in various fed-batch assays using a highly enriched PHA accumulating biomass as inoculum, where the potential for biopolymer production from the remaining acetic acid at the end of the syngas fermentation was evaluated. All of the acetic acid was consumed and accumulated as biopolymer, while ethanol and 2,3-butanediol remained basically unused. It can be concluded that a high C/N ratio in the effluent from the syngas fermentation stage was responsible for non-consumption of alcohols. A maximum PHA content of 24% was reached at the end of the assay. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Development of an Integrated Biofuel and Chemical Refinery

    Energy Technology Data Exchange (ETDEWEB)

    Trawick, John [Genomatica, San Diego, CA (United States); Burk, Mark [Genomatica, San Diego, CA (United States); Barton, Nelson [Genomatica, San Diego, CA (United States)

    2017-02-06

    This project has demonstrated the level of commercial readiness for production of the industrial chemical, 1,4-butanediol (BDO), from lignocellulosic biomass by engineered E. coli. Targets were BDO titer, rate, and yield (TRY) and growth in lignocellulosic hydrolysates (Hz). A range of Hzs were used to assess limitations for biomass-to-BDO. Via adaptive evolution methods, whole-genome sequencing, and introduction of identified target genes, strains co-utilizing C5/ C6 sugars were made. The composition of Hz versus TRY led to a modified Hz composition. This was used in partnership with the DOE to redirect the project to focus on 1) several biomass Hz from new suppliers, 2) Hz specification due to the characteristics of the Genomatica BDO process, 3) a gene cassette to engineer any BDO producing strain for biomass, and 4) modified BDO recovery to more economically recover BDO at industry specifications. BDO TRY and growth of the E. coli strains were predictable based on Hz composition from several suppliers. This defined metrics for biomass Hz composition to achieve BDO TRY along with internal TEA to evaluate the economic potential of each modification to strain, Hz feed, and process. An improved biomass-to-BDO production strain reached BDO T-R in a 30 L fermentation above original objectives. Yield approached the proposed Y and modifications to BDO recovery were demonstrated. Genomatica is now in the position of being able to incorporate biomass feedstocks into the commercial GENO BDO process.

  12. Polyurethane/fluor-hydroxyapatite nanocomposite scaffolds for bone tissue engineering. Part I: morphological, physical, and mechanical characterization.

    Science.gov (United States)

    Asefnejad, Azadeh; Behnamghader, Aliasghar; Khorasani, Mohammad Taghi; Farsadzadeh, Babak

    2011-01-06

    In this study, new nano-fluor-hydroxyapatite (nFHA)/polyurethane composite scaffolds were fabricated for potential use in bone tissue engineering. Polyester urethane samples were synthesized from polycaprolactone, hexamethylene diisocyanate, and 1,4-butanediol as chain extender. Nano fluor-hydroxyapatite (nFHA) was successfully synthesized by sol-gel method. The solid-liquid phase separation and solvent sublimation methods were used for preparation of the porous composites. Mechanical properties, chemical structure, and morphological characteristics of the samples were investigated by compressive test, Fourier transform infrared, and scanning electron microscopy (SEM) techniques, respectively. The effect of nFHA powder content on porosity and pore morphology was investigated. SEM images demonstrated that the scaffolds were constituted of interconnected and homogeneously distributed pores. The pore size of the scaffolds was in the range 50-250 μm. The result obtained in this research revealed that the porosity and pore average size decreased and compressive modulus increased with nFHA percentage. Considering morphological, physical, and mechanical properties, the scaffold with a higher ratio of nFHA has suitable potential use in tissue regeneration.

  13. High-level production of diacetyl in a metabolically engineered lactic acid bacterium

    DEFF Research Database (Denmark)

    2017-01-01

    The present invention provides a genetically modified lactic acid bacterium capable of producing diacetyl under aerobic conditions. Additionally the invention provides a method for producing diacetyl using the genetically modified lactic acid bacterium under aerobic conditions in the presence of .......C. 1.1.1.4/1.1.1.-) and alcohol dehydrogenase (E.C. 1.2.1.10) activity. The invention provides for use of the genetically modified lactic acid bacterium for the production of diacetyl and a food product....... of a source of iron-containing porphyrin and a metal ion selected from Fe3+, Fe2+ and Cu2+. The lactic acid bacterium is genetically modified by deletion of those genes in its genome that encode polypeptides having lactate dehydrogenase (E.C 1.1.1.27/E.C.1.1.1.28); α-acetolactate decarboxylase (E.C 4.......1.1.5); water-forming NADH oxidase (E.C. 1.6.3.4); phosphotransacetylase (E.C.2.3.1.8) activity; and optionally devoid of or deleted for genes encoding polypeptides having diacetyl reductase ((R)-acetoin forming; EC: 1.1.1.303); D-acetoin reductase; butanediol dehydrogenase ((R,R)-butane-2,3-diol forming; E...

  14. 2-Butanol and butanone production in Saccharomyces cerevisiae through combination of a B12 dependent dehydratase and a secondary alcohol dehydrogenase using a TEV-based expression system.

    Directory of Open Access Journals (Sweden)

    Payam Ghiaci

    Full Text Available 2-Butanol and its chemical precursor butanone (methyl ethyl ketone--MEK are chemicals with potential uses as biofuels and biocommodity chemicals. In order to produce 2-butanol, we have demonstrated the utility of using a TEV-protease based expression system to achieve equimolar expression of the individual subunits of the two protein complexes involved in the B12-dependent dehydratase step (from the pdu-operon of Lactobacillus reuteri, which catalyze the conversion of meso-2,3-butanediol to butanone. We have furthermore identified a NADH dependent secondary alcohol dehydrogenase (Sadh from Gordonia sp. able to catalyze the subsequent conversion of butanone to 2-butanol. A final concentration of 4±0.2 mg/L 2-butanol and 2±0.1 mg/L of butanone was found. A key factor for the production of 2-butanol was the availability of NADH, which was achieved by growing cells lacking the GPD1 and GPD2 isogenes under anaerobic conditions.

  15. A site-holding effect of TiO2 surface hydroxyl in the photocatalytic direct synthesis of 1,1-diethoxyethane from ethanol.

    Science.gov (United States)

    Zhang, Hongxia; Zhang, Wenqin; Zhao, Min; Yang, Pengju; Zhu, Zhenping

    2017-01-26

    To understand the mechanism of the photocatalytic direct synthesis of 1,1-diethoxyethane (DEE) from ethanol is vital for enhancing the reaction efficiency. Based on photocatalytic data of different phase TiO2 and F-TiO2 catalysts, radical trapping data, and GC-MS data, we proposed a photocatalytic mechanism for the preparation of both DEE in neat ethanol and 2,3-butanediol (2,3-BD) in ethanol-H2O using photocatalytic methods. In neat ethanol, hydroxyl isn't involved in the catalytic cyclic process but hydroxyl has an indirect site-holding effect, thus leading to more hydroxyl groups with higher activity. In ethanol-H2O, although the strong oxidant ˙OH radical is involved, fewer OH groups lead to higher selectivity of 2,3-BD. The interaction of the reactant/solvent with the surface group of the catalyst is important in the activity and selectivity of photocatalytic reactions. This finding gives fundamental insight into the role of TiO2 surface hydroxyl in the photocatalytic dehydrogenation process of alcohols and opens a promising path to obtaining both high selectivity and high conversion in TiO2-based photocatalytic activity.

  16. Poly(butylene 2,5-furandicarboxylate-ε-caprolactone: A new bio-based elastomer with high strength and biodegradability

    Directory of Open Access Journals (Sweden)

    M. Y. Zheng

    2017-08-01

    Full Text Available A new bio-based elastomer, poly(butylene 2,5-furandicarboxylate-ε-caprolactone (PBFCL, has been synthesized from 2,5-furandicarboxylic acid, 1,4-butanediol, and ε-caprolactone successfully for the first time. The obtained copolyester was characterized in terms of chemical structure, thermal and mechanical properties, and enzymatic degradability. In PBFCL elastomer, butylene-2,5-furandiacrboxylate units (hard segments crystallize to serve as physical crosslinks while ε-caprolactone polyester diol (soft segments provide flexibility. PBFCL is a multi-blocked copolyester with randomly distributed rigid and soft segments. It possesses original feature of high strength and biodegradability stemming from the uses of aromatic and aliphatic monomers respectively. An important aspect of this new furanic-aliphatic polyester is its tailor-made properties simply achieved by changing the content of hard or soft segments. Typically, PBFCL-40 of optimal composition has Young’s modulus as low as 15.4 MPa, tensile strength as high 24.8 MPa, and elongation as long as 885%.

  17. Electrochemical sensing of H2O2 by the modified electrode with pd nanoparticles on multi-walled carbon nanotubes-g-poly(lactic acid).

    Science.gov (United States)

    Han, Hyoung Soon; You, Jung-Min; Jeong, Haesang; Jeon, Seungwon

    2014-06-01

    A simple method has adapted to prepare MWCNT grafted Poly(lactic acid) (MWCNT-g-PLA) by intercalative polymerization of poly(lactic acid) in the presence of multi-wall carbon nanotubes (MWCNT) functionalized with hydroxyl groups. The functionalized MWCNT has obtained from the treatment of methylene diphenyl diisocyanate (MDI) with MWCNT, and then the reaction with 1,4-butanediol (BD) to create functional hydroxyl groups. MWCNT-g-PLA-Pd and MWCNT-g-PLA-Pt have prepared from the MWCNT-g-PLA and metal precursors. The synthesized materials have characterized by 1H-NMR, Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM). The MWCNT-g-PLA-Pd is possibilities for employing to electrochemical detection of hydrogen peroxide. Electrocatalytic activities are verified from cyclic voltammetry (CV) and amperometric response in 0.1 M phosphate buffer solution (PBS). The biosensor provided good stability and selectivity towards interferences such as UA, AA, and glucose.

  18. Chiral ligand exchange capillary electrophoresis using borate anion as a central ion.

    Science.gov (United States)

    Kodama, Shuji; Yamamoto, Atsushi; Iio, Reiko; Sakamoto, Keiji; Matsunaga, Akinobu; Hayakawa, Kazuichi

    2004-12-01

    Native DL-pantothenic acid, having a 1,3-diol structure, was chirally resolved by ligand exchange capillary electrophoresis using (S)-3-amino-1,2-propanediol as a chiral selector and the borate anion as a central ion. The optimum conditions for both high resolution and short migration time of DL-pantothenic acid were found to be 200 mM (S)-3-amino-1,2-propanediol and 200 mM borate buffer (pH 9.2) containing 15% methanol with an applied voltage of +25 kV at 20 degrees C, using direct detection at 200 nm. With this system, the resolution (Rs) of racemic pantothenic acid was approximately 1.7. When (S)-1,2-propanediol, (S)-1,2,3-propanetriol, (S)-1,3-butanediol or (S)-1-amino-2-propanol were used as chiral ligand instead of (S)-3-amino-1,2-propanediol, DL-pantothenic acid was not enantioseparated. When borate was replaced with Tris or butylborate, no chiral separation was achieved. Therefore, the ionic interaction between the amino and carboxyl groups of the ternary complex may play an important role in the enantioseparation of DL-pantothenic acid by the proposed CE system.

  19. Genome Sequencing of a Mung Bean Plant Growth Promoting Strain of P. aeruginosa with Biocontrol Ability

    Directory of Open Access Journals (Sweden)

    Devaraj Illakkiam

    2014-01-01

    Full Text Available Pseudomonas aeruginosa PGPR2 is a mung bean rhizosphere strain that produces secondary metabolites and hydrolytic enzymes contributing to excellent antifungal activity against Macrophomina phaseolina, one of the prevalent fungal pathogens of mung bean. Genome sequencing was performed using the Ion Torrent Personal Genome Machine generating 1,354,732 reads (6,772,433 sequenced bases achieving ~25-fold coverage of the genome. Reference genome assembly using MIRA 3.4.0 yielded 198 contigs. The draft genome of PGPR2 encoded 6803 open reading frames, of which 5314 were genes with predicted functions, 1489 were genes of known functions, and 80 were RNA-coding genes. Strain specific and core genes of P. aeruginosa PGPR2 that are relevant to rhizospheric habitat were identified by pangenome analysis. Genes involved in plant growth promoting function such as synthesis of ACC deaminase, indole-3-acetic acid, trehalose, mineral scavenging siderophores, hydrogen cyanide, chitinases, acyl homoserine lactones, acetoin, 2,3-butanediol, and phytases were identified. In addition, niche-specific genes such as phosphate solubilising 3-phytase, adhesins, pathway-specific transcriptional regulators, a diguanylate cyclase involved in cellulose synthesis, a receptor for ferrienterochelin, a DEAD/DEAH-box helicase involved in stress tolerance, chemotaxis/motility determinants, an HtpX protease, and enzymes involved in the production of a chromanone derivative with potent antifungal activity were identified.

  20. Metabolic modeling of synthesis gas fermentation in bubble column reactors.

    Science.gov (United States)

    Chen, Jin; Gomez, Jose A; Höffner, Kai; Barton, Paul I; Henson, Michael A

    2015-01-01

    A promising route to renewable liquid fuels and chemicals is the fermentation of synthesis gas (syngas) streams to synthesize desired products such as ethanol and 2,3-butanediol. While commercial development of syngas fermentation technology is underway, an unmet need is the development of integrated metabolic and transport models for industrially relevant syngas bubble column reactors. We developed and evaluated a spatiotemporal metabolic model for bubble column reactors with the syngas fermenting bacterium Clostridium ljungdahlii as the microbial catalyst. Our modeling approach involved combining a genome-scale reconstruction of C. ljungdahlii metabolism with multiphase transport equations that govern convective and dispersive processes within the spatially varying column. The reactor model was spatially discretized to yield a large set of ordinary differential equations (ODEs) in time with embedded linear programs (LPs) and solved using the MATLAB based code DFBAlab. Simulations were performed to analyze the effects of important process and cellular parameters on key measures of reactor performance including ethanol titer, ethanol-to-acetate ratio, and CO and H2 conversions. Our computational study demonstrated that mathematical modeling provides a complementary tool to experimentation for understanding, predicting, and optimizing syngas fermentation reactors. These model predictions could guide future cellular and process engineering efforts aimed at alleviating bottlenecks to biochemical production in syngas bubble column reactors.

  1. TECHNOLOGIES OF SYNTHESIS OF ORGANIC SUBSTANCES BY MICROORGANISMS USING WASTE BIODIESEL PRODUCTION

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    Pirog T. P.

    2015-08-01

    Full Text Available We describe here literature and our experimental data concerning microbial synthesis using waste biodiesel production, mono- and dihydric alcohols (1,3-propanediol, 2,3-butanediol, butanol, ethanol, polyols (mannitol, erythritol, arabitol, organic acids (citric, succinic, lactic, glyceric, polymers and compounds with a complex structure (polysaccharides, polyhydroxyalkanoates, surfactants, cephalosporin, cyanocobalamin. In some mentioned cases recombinant producer strains were used. It was shown that due to the presence of potential inhibitors in the composition of technical (crude glycerol (methanol, sodium and potassium salts, the efficiency of synthesis of most microbial products on such a substrate is lower than on the purified glycerol. However, the need of utilization of this toxic waste (storage and processing of crude glycerol is a serious environmental problem due to the high alkalinity and the content of methanol in it, compensates the lower rates of synthesis of the final product. Furthermore, currently considering the volumes of crude glycerol formed during the production of biodiesel, microbial technologies are preferred for its utilization, allowing realizing biosynthesis of practically valuable metabolites in the environment with the highest possible concentration of this waste. Using of crude glycerol as a substrate will reduce the cost of products of microbial synthesis and increase the profitability of biodiesel production.

  2. Safety and technological characterization of coagulase-negative staphylococci isolates from traditional Korean fermented soybean foods for starter development.

    Science.gov (United States)

    Jeong, Do-Won; Lee, Bitnara; Her, Jae-Young; Lee, Kwang-Geun; Lee, Jong-Hoon

    2016-11-07

    To select starters for the production of meju and doenjang, traditional Korean fermented soybean foods, we assessed the safety and technological properties of their predominant isolates, Staphylococcus saprophyticus, Staphylococcus succinus and Staphylococcus xylosus. Phenotypic antibiotic resistance, hemolysis and biofilm formation were strain-specific. None of the S. succinus isolates exhibited antibiotic resistance or hemolytic activities. Thirty-three selected strains, identified through safety assessments of 81 coagulase-negative staphylococci (CNS) isolates, produced cadaverine, putrescine, and tyramine, but not histamine in the laboratory setting. The production of these three biogenic amines may, however, be insignificant considering the high levels of tyramine produced by the control, Enterococcus faecalis. The 33 CNS strains could grow on tryptic soy agar containing 21% NaCl (w/v), exhibited acid producing activity at 15% NaCl, and expressed strain-specific protease and lipase activities. S. succinus 14BME1, the selected starter candidate, produced significant amounts of benzeneacetic acid, 2,3-butanediol, trimethylpyrazine, and tetramethylpyrazine through soybean fermentation. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Novel consortium of Klebsiella variicola and Lactobacillus species enhances the functional potential of fermented dairy products by increasing the availability of branched-chain amino acids and the amount of distinctive volatiles.

    Science.gov (United States)

    Rosales-Bravo, H; Morales-Torres, H C; Vázquez-Martínez, J; Molina-Torres, J; Olalde-Portugal, V; Partida-Martínez, L P

    2017-11-01

    Identify novel bacterial taxa that could increase the availability of branched-chain amino acids and the amount of distinctive volatiles during skim milk fermentation. We recovered 344 bacterial isolates from stool samples of healthy and breastfed infants. Five were selected based on their ability to produce branched-chain amino acids. Three strains were identified as Escherichia coli, one as Klebsiella pneumoniae and other as Klebsiella variicola by molecular and biochemical methods. HPLC and solid-phase microextraction with GC-MS were used for the determination of free amino acids and volatile compounds respectively. The consortium formed by K. variicola and four Lactobacillus species showed the highest production of Leu and Ile in skim milk fermentation. In addition, the production of volatile compounds, such as acetoin, ethanol, 2-nonanone, and acetic, hexanoic and octanoic acids, increased in comparison to commercial yogurt, Emmental and Gouda cheese. Also, distinctive volatiles, such as 2,3-butanediol, 4-methyl-2- hexanone and octanol, were identified. The use of K. variicola in combination with probiotic Lactobacillus species enhances the availability of Leu and Ile and the amount of distinctive volatiles during skim milk fermentation. The identified consortium increases the functional potential of fermented dairy products. © 2017 The Society for Applied Microbiology.

  4. Whole genome analysis of halotolerant and alkalotolerant plant growth-promoting rhizobacterium Klebsiella sp. D5A

    Science.gov (United States)

    Liu, Wuxing; Wang, Qingling; Hou, Jinyu; Tu, Chen; Luo, Yongming; Christie, Peter

    2016-05-01

    This research undertook the systematic analysis of the Klebsiella sp. D5A genome and identification of genes that contribute to plant growth-promoting (PGP) traits, especially genes related to salt tolerance and wide pH adaptability. The genome sequence of isolate D5A was obtained using an Illumina HiSeq 2000 sequencing system with average coverages of 174.7× and 200.1× using the paired-end and mate-pair sequencing, respectively. Predicted and annotated gene sequences were analyzed for similarity with the Kyoto Encyclopedia of Genes and Genomes (KEGG) enzyme database followed by assignment of each gene into the KEGG pathway charts. The results show that the Klebsiella sp. D5A genome has a total of 5,540,009 bp with 57.15% G + C content. PGP conferring genes such as indole-3-acetic acid (IAA) biosynthesis, phosphate solubilization, siderophore production, acetoin and 2,3-butanediol synthesis, and N2 fixation were determined. Moreover, genes putatively responsible for resistance to high salinity including glycine-betaine synthesis, trehalose synthesis and a number of osmoregulation receptors and transport systems were also observed in the D5A genome together with numerous genes that contribute to pH homeostasis. These genes reveal the genetic adaptation of D5A to versatile environmental conditions and the effectiveness of the isolate to serve as a plant growth stimulator.

  5. Shrinkage Characteristics of Experimental Polymer Containing Composites under Controlled Light Curing Modes

    Directory of Open Access Journals (Sweden)

    Alain Pefferkorn

    2012-01-01

    Full Text Available The adsorption of polymethylmethacrylate polymer of different molecular weight at the aerosil/ethyleneglycol- or 1,3 butanediol-dimethacrylate interfaces was determined to provide microstructured networks. Their structural characteristics were determined to be controlled by the amount of polymer initially supplied to the system. The sediment (the settled phase characteristics, determined as a function of the polymer concentration and the rate of the polymerization shrinkage determined for composite resins, obtained by extrusion of the sediment after centrifugation, were found to be correlated. The specific role of the adsorbed polymer was found to be differently perturbed with the supplementary supply of dimethacrylate based monomer additives. Particularly, the bisphenol A dimethacrylate that generated crystals within the sediment was found to impede the shrinkage along the crystal lateral faces and strongly limit the shrinkage along its basal faces. Addition of ethyleneglycol- or polyethylene-glycoldimethacrylate monomers was determined to modify the sedimentation characteristics of the aerosil suspension and the shrinkage properties of the composites. Finally, the effects of stepwise light curing methods with prolonged lighting-off periods were investigated and found to modify the development and the final values of the composite shrinkage.

  6. Effects of GPD1 Overexpression in Saccharomyces cerevisiae Commercial Wine Yeast Strains Lacking ALD6 Genes

    Science.gov (United States)

    Cambon, Brigitte; Monteil, Virginie; Remize, Fabienne; Camarasa, Carole; Dequin, Sylvie

    2006-01-01

    The utilization of Saccharomyces cerevisiae strains overproducing glycerol and with a reduced ethanol yield is a potentially valuable strategy for producing wine with decreased ethanol content. However, glycerol overproduction is accompanied by acetate accumulation. In this study, we evaluated the effects of the overexpression of GPD1, coding for glycerol-3-phosphate dehydrogenase, in three commercial wine yeast strains in which the two copies of ALD6 encoding the NADP+-dependent Mg2+-activated cytosolic acetaldehyde dehydrogenase have been deleted. Under wine fermentation conditions, the engineered industrial strains exhibit fermentation performance and growth properties similar to those of the wild type. Acetate was produced at concentrations similar to that of the wild-type strains, whereas sugar was efficiently diverted to glycerol. The ethanol yield of the GPD1 ald6 industrial strains was 15 to 20% lower than that in the controls. However, these strains accumulated acetoin at considerable levels due to inefficient reduction to 2,3-butanediol. Due to the low taste and odor thresholds of acetoin and its negative sensorial impact on wine, novel engineering strategies will be required for a proper adjustment of the metabolites at the acetaldehyde branch point. PMID:16820460

  7. Effect of Hydroxyapatite Nanoparticles on the Degradability of Random Poly(butylene terephthalate-co-aliphatic dicarboxylates Having a High Content of Terephthalic Units

    Directory of Open Access Journals (Sweden)

    Nina Heidarzadeh

    2016-07-01

    Full Text Available Copolyesters derived from 1,4-butanediol and constituted also of aliphatic and aromatic dicarboxylate units in a molar ratio of 3:7 were synthesized by a two-step polycondensation procedure. Succinic, adipic, and sebacic acids were specifically selected as the aliphatic component whereas terephthalic acid was chosen as the aromatic moiety. The second synthesis step was a thermal transesterification between the corresponding homopolymers, always attaining a random distribution as verified by NMR spectroscopy. Hybrid polymer composites containing 2.5 wt % of hydroxyapatite (HAp were also prepared by in situ polymerization. Hydroxyl groups on the nanoparticle surface allowed the grafting of polymer chains in such a way that composites were mostly insoluble in the typical solvents of the parent copolyesters. HAp had some influence on crystallization from the melt, thermal stability, and mechanical properties. HAp also improved the biocompatibility of samples due to the presence of Ca2+ cations and the damping effect of phosphate groups. Interestingly, HAp resulted in a significant increase in the hydrophilicity of samples, which considerably affected both enzymatic and hydrolytic degradability. Slight differences were also found in the function of the dicarboxylic component, as the lowest degradation rates was found for the sample constituted of the most hydrophobic sebacic acid units.

  8. Growth and end-product formation in fermenter cultures of Brochothrix thermosphacta ATCC 11509T and two psychrotrophic Lactobacillus spp. in different gaseous atmospheres.

    Science.gov (United States)

    Blickstad, E; Molin, G

    1984-10-01

    The effects of different gaseous atmospheres were determined on the maximum specific growth rate (mumax) and end-product formation by Brochothrix thermosphacta ATCC 11509T, Lactobacillus viridescens SMRICC 174 and Lactobacillus sp. SMRICC 173 (homofermentative). The highest mumax-values for Lact. viridescens (0.47/h) and Broc. thermosphacta (0.49/h) were obtained in air. Under anaerobic conditions mumax was reduced, an atmosphere containing CO2 alone giving the greatest reduction. Lactobacillus sp. 173 did not grow in air or N2. Aerobic growth was obtained by adding peroxidase while anaerobic growth occurred in the presence of 5-20% CO2. Carbon dioxide alone reduced the growth rate. All test organisms produced mainly lactic acid anaerobically. Lactobacillus viridescens also produced ethanol while Broc. thermosphacta produced small amounts of ethanol and formic acid. With O2 present, the number of end-products increased for all organisms. Lactobacillus sp. 173 produced small amounts of acetic acid and acetoin together with lactic acid. Oxygen induced acetic acid production in Lact. viridescens and Broc. thermosphacta. Aerobically, Broc. thermosphacta also produced a large amount of acetoin and smaller amounts of 2,3-butanediol, iso-valeric acid and iso-butyric acid. The production of lactic acid by Broc. thermosphacta was completely prevented under strictly aerobic conditions. All test organisms consumed O2 during aerobic growth. Hydrogen peroxide was produced by Lact. viridescens and Lactobacillus sp. 173.

  9. Life-cycle fossil energy consumption and greenhouse gas emissions of bioderived chemicals and their conventional counterparts.

    Science.gov (United States)

    Adom, Felix; Dunn, Jennifer B; Han, Jeongwoo; Sather, Norm

    2014-12-16

    Biomass-derived chemical products may offer reduced environmental impacts compared to their fossil-derived counterparts and could improve profit margins at biorefineries when coproduced with higher-volume, lower-profit margin biofuels. It is important to assess on a life-cycle basis the energy and environmental impacts of these bioproducts as compared to conventional, fossil-derived products. We undertook a life-cycle analysis of eight bioproducts produced from either algal-derived glycerol or corn stover-derived sugars. Selected on the basis of technology readiness and market potential, the bioproducts are propylene glycol, 1,3-propanediol, 3-hydroxypropionic acid, acrylic acid, polyethylene, succinic acid, isobutanol, and 1,4-butanediol. We developed process simulations to obtain energy and material flows in the production of each bioproduct and examined sensitivity of these flows to process design assumptions. Conversion process data for fossil-derived products were based on the literature. Conversion process data were combined with upstream parameters in the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model to generate life-cycle greenhouse gas (GHG) emissions and fossil energy consumption (FEC) for each bioproduct and its corresponding petroleum-derived product. The bioproducts uniformly offer GHG emissions reductions compared to their fossil counterparts ranging from 39 to 86% on a cradle-to-grave basis. Similarly, FEC was lower for bioproducts than for conventional products.

  10. Harnessing the respiration machinery for high-yield production of chemicals in metabolically engineered Lactococcus lactis

    DEFF Research Database (Denmark)

    Liu, Jianming; Wang, Zhihao; Kandasamy, Vijayalakshmi

    2017-01-01

    When modifying the metabolism of living organisms with the aim of achieving biosynthesis of useful compounds, it is essential to ensure that it is possible to achieve overall redox balance. We propose a generalized strategy for this, based on fine-tuning of respiration. The strategy was applied...... on metabolically engineered Lactococcus lactis strains to optimize the production of acetoin and (R,R)−2,3-butanediol (R-BDO). In the absence of an external electron acceptor, a surplus of two NADH per acetoin molecule is produced. We found that a fully activated respiration was able to efficiently regenerate NAD...... is converted into R-BDO per mole, only the excess of NADH needs to be oxidized via respiration. Either by fine-tuning the respiration capacity or by using a dual-phase fermentation approach involving a switch from fully respiratory to non-respiratory conditions, we obtained 361 mM (32 g/L) R-BDO with a yield...

  11. Physiological and metabolic analysis of nitrate reduction on poly-gamma-glutamic acid synthesis in Bacillus licheniformis WX-02.

    Science.gov (United States)

    Li, Xin; Gou, Xiangyong; Long, Dan; Ji, Zhixia; Hu, Lifang; Xu, Dihong; Liu, Jun; Chen, Shouwen

    2014-11-01

    Nitrate is an important nitrogen source for organism, but whether and how nitrate improves poly-γ-glutamic acid (γ-PGA) production of bacterial is not clear. The effect of nitrate on γ-PGA production of Bacillus licheniformis WX-02 was investigated. By addition of 50 mmol/L nitrate, the γ-PGA yield reached 12.3 ± 0.21 g/L, which increased 2.3-fold compared to the control. The mechanism of enhanced γ-PGA production was further investigated by analysis of nitrate reduction, physiology, pyruvate overflow metabolism and energy synthesis. Nitrate reduction was only carried out in the middle stage of γ-PGA fermentation. The result of consumption of nutrients showed that glucose uptake was not effected and the L-glutamic acid utilization efficiency increased from 48.3 to 77.0 %. The date of overflow metabolism obtained from high-performance liquid chromatography showed that the metabolism of pyruvate, formate, lactate and acetoin was both heightened by nitrate reduction, while the 2,3-butanediol biosynthesis was decreased. Meanwhile, the change of energy indicated that more ATP was synthesized during nitrate reduction. In summary, nitrate was a positive effector of γ-PGA biosynthesis in B. licheniformis WX-02 and nitrate reduction affected multi-metabolism pathways, including glycolysis, overflow metabolism and energy metabolism.

  12. Evaluation of the Mechanical Properties of Microcapsule-Based Self-Healing Composites

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    Liberata Guadagno

    2016-01-01

    Full Text Available Self-healing materials are beginning to be considered for applications in the field of structural materials. For this reason, in addition to self-healing efficiency, also mechanical properties such as tensile and compressive properties are beginning to become more and more important for this kind of materials. In this paper, three different systems based on epoxy-resins/ethylidene-norbornene (ENB/Hoveyda-Grubbs 1st-generation (HG1 catalyst are investigated in terms of mechanical properties and healing efficiency. The experimental results show that the mechanical properties of the self-healing systems are mainly determined by the chemical nature of the epoxy matrix. In particular, the replacement of a conventional flexibilizer (Heloxy 71 with a reactive diluent (1,4-butanediol diglycidyl ether allows obtaining self-healing materials with better mechanical properties and higher thermal stability. An increase in the curing temperature causes an increase in the elastic modulus and a slight reduction of the healing efficiency. These results can constitute the basis to design systems with high regenerative ability and appropriate mechanical performance.

  13. Pathway engineering of Enterobacter aerogenes to improve acetoin production by reducing by-products formation.

    Science.gov (United States)

    Jang, Ji-Woong; Jung, Hwi-Min; Im, Dae-Kyun; Jung, Moo-Young; Oh, Min-Kyu

    2017-11-01

    Enterobacter aerogenes was metabolically engineered for acetoin production. To remove the pathway enzymes that catalyzed the formation of by-products, the three genes encoding a lactate dehydrogenase (ldhA) and two 2,3-butanediol dehydrogenases (budC, and dhaD), respectively, were deleted from the genome. The acetoin production was higher under highly aerobic conditions. However, an extracellular glucose oxidative pathway in E. aerogenes was activated under the aerobic conditions, resulting in the accumulation of 2-ketogluconate. To decrease the accumulation of this by-product, the gene encoding a glucose dehydrogenase (gcd) was also deleted. The resulting strain did not produce 2-ketogluconate but produced significant amounts of acetoin, with concentration reaching 71.7g/L with 2.87g/L/h productivity in fed-batch fermentation. This result demonstrated the importance of blocking the glucose oxidative pathway under highly aerobic conditions for acetoin production using E. aerogenes. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. MIXED SUBSTRATES IN ENVIRONMENT AND BIOTECHNOLOGICAL PROCESSES

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    T. P. Pirog

    2013-12-01

    Full Text Available The modern literature and own experimental data on the use of substrates’ mixtures for intensification of microbial synthesis technologies of practically valuable fermentation products (ethanol, lactic acid, butanediol, primary (amino acids, n-hydroxybenzoate, triglycerides and secondary (lovastatin, surfactants metabolites as well as for intensification of biodegradation of aromatic xenobiotics (benzene, cresols, phenols, toluene and pesticides (dimethoate are presented. Special attention is paid on the molecular mechanisms that were established in recent years and underlying the phenomenon catabolic repression in Gram-positive (Bacillus subtilis and Gram-negative (Pseudomonas, Escherichia coli bacteria and yeast Saccharomyces cerevisiae, and on the use of these data to develop technologies for utilization of plant biomass to produce industrially important metabolites. The survival strategies of heterotrophic microorganisms in natural oligotrophic environments are considered, including the simultaneous use of multiple substrates, allowing improved kinetic characteristics that give them a competitive advantage, also provided significant metabolic/physiological flexibility. The own experimental data on the use of mixtures of growth substrates for the intensification of surfactants’ synthesis of Rhodococcus erythropolis IMV Ac-5017 and Acinetobacter calcoaceticus IMV B-7241 are summarized. The dependence of the synthesis of surfactants in a mixture of energy excess (hexadecane and energy deficient (glycerol, ethanol substrates on the way of inoculum preparation, concentration of mono-substrates in the mixture, and their molar ratio were determined.

  15. Synthesis of polycarbonate urethane elastomers and effects of the chemical structures on their thermal, mechanical and biocompatibility properties

    Directory of Open Access Journals (Sweden)

    Rong Zhu

    2016-06-01

    Full Text Available In this study, to obtain biomedical polyurethane elastomers with good mechanical properties and biocompatibility, a series of polycarbonate urethanes were synthesized via a two-step solution of polymerization method using the poly(1,6-hexanediolcarbonate diols (PCDL as the soft segment, 4,4′-methylenebis(cyclohexyl isocyanate (H12MDI, 1,6-hexamethylene diisocyanate (HDI and 1,4-butanediol (BDO as the hard segment with dibutyltin dilaurate as the catalyst. In this article, we illustrated the physical behaviors were obviously influenced by synthetic routes. And their chemical and physical structures were investigated by gel permeation chromatograph (GPC, differential scanning calorimeter (DSC, fourier transform infrared spectrography (FT-IR and mechanical properties tests. The surface wettability were studied by contact angle measurement (CA. As a kind of short-term implant biomaterial, the results of the hemolysis and platelet adhesive tests were recorded by spectrophotometer and scanning electron microscopy (SEM, indicating the materials have a great potential for developments and applications in biomedical field.

  16. Influence of Hard Segments on the Thermal, Phase-Separated Morphology, Mechanical, and Biological Properties of Polycarbonate Urethanes

    Directory of Open Access Journals (Sweden)

    Rong Zhu

    2017-03-01

    Full Text Available Abstract: In this study, we have fabricated a series of polycarbonate polyurethanes using a two-step bulk reaction by the melting pre-polymer solution-casting method in order to synthesize biomedical polyurethane elastomers with good mechanical behavior and biostability. The polyurethanes were prepared using dibutyltin dilaurate as the catalyst, poly(1,6-hexanediolcarbonate microdiols (PCDL as the soft segment, and the chain extender 1,4-butanediol (BDO and aliphatic 1,6-hexamethylene diisocyanate (HDI as the hard segments. The chemical structures and physical properties of the obtained films were characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR spectroscopy, gel permeation chromatography (GPC, differential scanning calorimeter (DSC, and mechanical property tests. The surface properties and degrees of microphase separation were further analyzed by water droplet contact angle measurements (CA and atomic force microscopy (AFM. The materials exhibited a moderate toxic effect on the tetrazolium (MTT assay and good hemocompatibility through hemolytic tests, indicating a good biocompatibility of the fabricated membranes. The materials could be considered as potential and beneficial suitable materials for tissue engineering, especially in the fields of artificial blood-contacting implants or other biomedical applications.

  17. CEC separation of heterocyclic amines using methacrylate monolithic columns.

    Science.gov (United States)

    Barceló-Barrachina, Elena; Moyano, Encarnación; Puignou, Lluís; Galceran, Maria Teresa

    2007-06-01

    Two methacrylate-based monolithic columns, one with a negatively charged group (sulfonic group) and another with a new monomer N,N-dimethylamino ethyl acrylate (DMAEA), were prepared and tested for the separation of basic compounds by CEC. This new monolithic stationary phase was prepared by the in situ polymerization of DMAEA with butyl methacrylate and ethylene dimethacrylate, using a ternary porogenic solvent consisting of water, 1-propanol and 1,4-butanediol. The performance of this column was evaluated by means of the analysis of a family of heterocyclic amines. Separation conditions such as pH, amount of organic modifier, ionic strength and elution mode (normal or counterdirectional flow) were studied. At the optimal running electrolyte composition, and using the counterdirectional mode, symmetrical electrochromatographic peaks were obtained, with the number of theoretical plates up to 30,000 and a good resolution between closely related peaks. The 2-acrylamido-2-methyl-1-propane-sulfonic acid column was used for CEC-MS, taking advantage of the compatibility of its elution mode (normal flow) with the MS coupling.

  18. Engineering Pichia pastoris for improved NADH regeneration: A novel chassis strain for whole-cell catalysis

    Directory of Open Access Journals (Sweden)

    Martina Geier

    2015-09-01

    Full Text Available Many synthetically useful reactions are catalyzed by cofactor-dependent enzymes. As cofactors represent a major cost factor, methods for efficient cofactor regeneration are required especially for large-scale synthetic applications. In order to generate a novel and efficient host chassis for bioreductions, we engineered the methanol utilization pathway of Pichia pastoris for improved NADH regeneration. By deleting the genes coding for dihydroxyacetone synthase isoform 1 and 2 (DAS1 and DAS2, NADH regeneration via methanol oxidation (dissimilation was increased significantly. The resulting Δdas1 Δdas2 strain performed better in butanediol dehydrogenase (BDH1 based whole-cell conversions. While the BDH1 catalyzed acetoin reduction stopped after 2 h reaching ~50% substrate conversion when performed in the wild type strain, full conversion after 6 h was obtained by employing the knock-out strain. These results suggest that the P. pastoris Δdas1 Δdas2 strain is capable of supplying the actual biocatalyst with the cofactor over a longer reaction period without the over-expression of an additional cofactor regeneration system. Thus, focusing the intrinsic carbon flux of this methylotrophic yeast on methanol oxidation to CO2 represents an efficient and easy-to-use strategy for NADH-dependent whole-cell conversions. At the same time methanol serves as co-solvent, inductor for catalyst and cofactor regeneration pathway expression and source of energy.

  19. Lack of RsmA-mediated control results in constant hypervirulence, cell elongation, and hyperflagellation in Pectobacterium wasabiae.

    Directory of Open Access Journals (Sweden)

    Viia Kõiv

    Full Text Available The posttranscriptional regulator RsmA controls the production of plant cell wall degrading enzymes (PCWDE and cell motility in the Pectobacterium genus of plant pathogens. In this study the physiological role of gene regulation by RsmA is under investigation. Disruption of rsmA gene of the Pectobacterium wasabiae strain, SCC3193 resulted in 3-fold decrease in growth rate and increased virulence. The comparison of mRNA levels of the rsmA(- mutant and wild-type using a genome-wide microarray showed, that genes responsible for successful infection, i.e. virulence factors, motility, butanediol fermentation, various secretion systems etc. were up-regulated in the rsmA(- strain. The rsmA(- strain exhibited a higher propensity to swarm and produce PCWDE compared to the wild-type strain. Virulence experiments in potato tubers demonstrated that in spite of its more efficient tissue maceration, the rsmA(- strain's ability to survive within the host is reduced and the infection site is taken over by resident bacteria. Taken together, in the absence of RsmA, cells revert to a constitutively infective phenotype characterized by expression of virulence factors and swarming. We hypothesize that lack of control over these costly energetic processes results in decreased growth rate and fitness. In addition, our findings suggest a relationship between swarming and virulence in plant pathogens.

  20. Sensitization to reactive diluents and hardeners in epoxy resin systems. IVDK data 2002-2011. Part II: concomitant reactions.

    Science.gov (United States)

    Geier, Johannes; Lessmann, Holger; Hillen, Uwe; Skudlik, Christoph; Jappe, Uta

    2016-02-01

    Beside the basic resins, reactive diluents and hardeners are important sensitizers in epoxy resin systems (ERSs). Because of chemical similarities, immunological cross-reactivity may occur. To analyse concomitant reactivity among reactive diluents and hardeners in the patients concerned, as one integral part of a research project on the sensitizing capacity of ERSs (FP-0324). A retrospective analysis of data from the Information Network of Departments of Dermatology (IVDK), 2002-2011, was performed. There was close concomitant reactivity to 1,6-hexanediol diglycidyl ether and 1,4-butanediol diglycidyl ether (1,4-BDDGE), and to phenyl glycidyl ether (PGE) and cresyl glycidyl ether (CGE), whereas reactions to p-tert-butylphenyl glycidyl ether occurred more independently from those to PGE and CGE. Concomitant reactions to butyl glycidyl ether and 1,4-BDDGE may point to a common allergenic compound derived from the metabolism of 1,4-BDDGE. Among the structurally more diverse group of hardeners, there was no evidence of immunological cross-reactions. More detailed knowledge of cross-reactivity among ERS components facilitates the interpretation of patch test results and will allow safer ERSs to be composed in the future. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Contact allergy to reactive diluents and related aliphatic epoxy resins.

    Science.gov (United States)

    Aalto-Korte, Kristiina; Kuuliala, Outi; Henriks-Eckerman, Maj-Len; Suuronen, Katri

    2015-06-01

    Diglycidyl ether of bisphenol A resin (DGEBA-R) is the most common sensitizer in epoxy systems, but a minority of patients also develop contact allergy to reactive diluents. To analyse the frequency and clinical relevance of allergic reactions to different epoxy reactive diluents and related aliphatic epoxy resins. Test files (January 1991 to June 2014) were screened, and the clinical records of patients with allergic reactions were analysed for occupation, concomitant allergic reactions, and exposure. A total of 67 patients reacted to at least one of the compounds. The largest numbers of allergic reactions were to phenyl glycidyl ether (PGE; n = 41), 1,4-butanediol diglycidyl ether (BDDGE; n = 34), and p-tert-butylphenyl glycidyl ether (PTBPGE; n = 19). Ten of the patients did not have contact allergy to DGEBA-R. The reactions of 5 of these were related to the use of BDDGE-containing products. We found no significant exposure to PGE or PTBPGE in patients sensitized to them, but some of the patients had used cresyl glycidyl ether-containing products. Allergic reactions to reactive diluents and related aliphatic epoxy resins usually occurred together with reactions to DGEBA-R. BDDGE was the clinically most significant compound, and was the sole cause of occupational allergic contact dermatitis in 3 patients. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Sensitization to reactive diluents and hardeners in epoxy resin systems. IVDK data 2002-2011. Part I: reaction frequencies.

    Science.gov (United States)

    Geier, Johannes; Lessmann, Holger; Hillen, Uwe; Skudlik, Christoph; Jappe, Uta

    2016-02-01

    Epoxy resin systems (ERSs), consisting of resins, reactive diluents, and hardeners, are indispensable in many branches of industry. In order to develop less sensitizing ERS formulations, knowledge of the sensitizing properties of single components is mandatory. To analyse the frequency of sensitization in the patients concerned, as one integral part of a research project on the sensitizing potency of epoxy resin compounds (FP-0324). A retrospective analysis of data from the Information Network of Departments of Dermatology (IVDK), 2002-2011, and a comparison of reaction frequencies with (surrogate) exposure data, were performed. Almost half of the patients sensitized to epoxy resin were additionally sensitized to reactive diluents or hardeners. Among the reactive diluents, 1,6-hexanediol diglycidyl ether was the most frequent allergen, followed by 1,4-butanediol diglycidyl ether, phenyl glycidyl ether, and p-tert-butylphenyl glycidyl ether. Among the hardeners, m-xylylene diamine (MXDA) and isophorone diamine (IPDA) were the most frequent allergens. According to the calculated exposure-related frequency of sensitization, MXDA seems to be a far more important sensitizer than IPDA. Up to 60% of the patients sensitized to hardeners and 15-20% of those sensitized to reactive diluents do not react to epoxy resin. In cases of suspected contact allergy to an ERS, a complete epoxy resin series must be patch tested from the start. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Optimization of Bicomponent Electrospun Fibers for Therapeutic Use: Post-Treatments to Improve Chemical and Biological Stability.

    Science.gov (United States)

    Papa, Antonio; Guarino, Vincenzo; Cirillo, Valentina; Oliviero, Olimpia; Ambrosio, Luigi

    2017-10-16

    Bicomponent electrospun nanofibers based on the combination of synthetic (i.e., aliphatic polyesters such as polycaprolactone (PCL)) and natural proteins (i.e., gelatin) have been extensively investigated as temporary platforms to instruct cells by the release of molecular/pharmaceutical signals for the regeneration of several tissues. Here, water soluble proteins (i.e., gelatin), strictly embedded to PCL, act as carriers of bioactive molecules, thus improving bioavailability and supporting cell activities during in vitro regeneration. However, these proteins are rapidly digested by enzymes, locally produced by many different cell types, both in vitro and in vivo, with significant drawbacks in the control of molecular release. Hence, we have investigated three post-processing strategies based on the use of different crosslinking agents-(1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride) (EDC), glyceraldehyde (GC), and 1,4-butanediol diglycidyl ether (BDDGE)-to delay the dissolution time of gelatin macromolecules from bicomponent fibers. All of the qualitative (i.e., SEM, TGA) and quantitative (i.e., Trinitrobenzene sulfonate (TNBS) and bicinchoninic acid (BCA) assays) morphological/chemical analyses as well as biocompatibility assays indicate that EDC crosslinking improves the chemical stability of bicomponent fibers at 37 °C and provides a more efficient encapsulation and controlled sustained release of drug, thus resulting in the best post-treatment to design bio-inspired fibrous platforms for the extended in vitro release of drugs.

  4. Comparison of phase structures and surface free energy values for the coatings synthesised from linear polyurethanes and from waterborne polyurethane cationomers.

    Science.gov (United States)

    Król, Piotr; Król, Bożena; Pielichowska, Kinga; Pikus, Stanisław

    2011-10-01

    WAXS, DSC and AFM methods were employed to compare phase structures of the coatings obtained from waterborne polyurethane cationomers which had been synthesised in the reaction of some diisocyanates (MDI, IPDI, TDI and HDI) with polyoxyethylene glycols (M = 600 and 2,000) and butane1,4-diol or N-methyl- or N-butyldiethanolamine and 2,2,3,3-tetrafluoro-1,4-butanediol. The structures were also analysed of the coatings derived from linear polyurethanes which had been synthesised on the basis of similar raw materials. Better rigidity was found for generally amorphous cationomer coats. Changes were discussed in the surface free energy (SFE) values and in their components, as calculated independently with the use of the van Oss-Good and Owens-Wendt methods. Polyurethane coats turned out more hydrophobic as compared to cationomer ones. In both coat types, fluorine incorporated into cationomers contributed to lower SFE values: from 50 down to about 30 mJ/m(2).

  5. Synthesis and characterization of biodegradable aliphatic copolyesters with hydrophilic soft segments

    Directory of Open Access Journals (Sweden)

    JASNA DJONLAGIC

    2004-12-01

    Full Text Available In this study, the synthesis, structure and physical properties of two series of segmented poly(ester-ethers based on poly(butylene succinate and two different types of polyethers were investigated. The poly(ester-ethers were synthesized by transesterification reaction of dimethyl succinate, 1,4-butanediol and poly(ethylene oxide (PEO, Mn = 1000 g/mol in the first series, and poly(tetramethylene oxide (PTMO, Mn = 1000 g/mol in the second. The mass fraction of soft segments was varied between 10 and 50 mass. %. The effect of the introduction of two different polyether soft segments on the structure, thermal and rheological properties were investigated. The composition of the poly(ester-ethers, determined from their 1H-NMR spectra, showed that incorporation of soft polyether segments was successfully performed by the transesterification reaction in bulk. The molecular weight was estimated from solution viscosity measurements and complex dynamic viscosities. The thermal properties investigated by DSC indicated that the presence of soft segments lowers the melting and crystallization temperature of the hard phase, as well as the degree of crystallinity. Dynamical mechanical analysis was used to investigate the influence of composition on the rheological behavior of the segmented poly(ester-ethers. The results obtained from an enzymatic degradation test performed on some of the synthesized polymers showed that the biodegradability is enhanced with increasing hydrophilicity.

  6. Activity of nanosized titania synthesized from thermal decomposition of titanium (IV n-butoxide for the photocatalytic degradation of diuron

    Directory of Open Access Journals (Sweden)

    Jitlada Klongdee, Wansiri Petchkroh, Kosin Phuempoonsathaporn, Piyasan Praserthdam, Alisa S. Vangnai and Varong Pavarajarn

    2005-01-01

    Full Text Available Nanoparticles of anatase titania were synthesized by the thermal decomposition of titanium (IV n-butoxide in 1,4-butanediol. The powder obtained was characterized by various characterization techniques, such as XRD, BET, SEM and TEM, to confirm that it was a collection of single crystal anatase with particle size smaller than 15 nm. The synthesized titania was employed as catalyst for the photodegradation of diuron, a herbicide belonging to the phenylurea family, which has been considered as a biologically active pollutant in soil and water. Although diuron is chemically stable, degradation of diuron by photocatalyzed oxidation was found possible. The conversions achieved by titania prepared were in the range of 70–80% within 6 h of reaction, using standard UV lamps, while over 99% conversion was achieved under solar irradiation. The photocatalytic activity was compared with that of the Japanese Reference Catalyst (JRC-TIO-1 titania from the Catalysis Society of Japan. The synthesized titania exhibited higher rate and efficiency in diuron degradation than reference catalyst. The results from the investigations by controlling various reaction parameters, such as oxygen dissolved in the solution, diuron concentration, as well as light source, suggested that the enhanced photocatalytic activity was the result from higher crystallinity of the synthesized titania.

  7. Quantitative NMR Metabolite Profiling of Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus Discriminates between Biofilm and Planktonic Phenotypes

    Science.gov (United States)

    2015-01-01

    Wound bioburden in the form of colonizing biofilms is a major contributor to nonhealing wounds. Staphylococcus aureus is a Gram-positive, facultative anaerobe commonly found in chronic wounds; however, much remains unknown about the basic physiology of this opportunistic pathogen, especially with regard to the biofilm phenotype. Transcriptomic and proteomic analysis of S. aureus biofilms have suggested that S. aureus biofilms exhibit an altered metabolic state relative to the planktonic phenotype. Herein, comparisons of extracellular and intracellular metabolite profiles detected by 1H NMR were conducted for methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) S. aureus strains grown as biofilm and planktonic cultures. Principal component analysis distinguished the biofilm phenotype from the planktonic phenotype, and factor loadings analysis identified metabolites that contributed to the statistical separation of the biofilm from the planktonic phenotype, suggesting that key features distinguishing biofilm from planktonic growth include selective amino acid uptake, lipid catabolism, butanediol fermentation, and a shift in metabolism from energy production to assembly of cell-wall components and matrix deposition. These metabolite profiles provide a basis for the development of metabolite biomarkers that distinguish between biofilm and planktonic phenotypes in S. aureus and have the potential for improved diagnostic and therapeutic use in chronic wounds. PMID:24809402

  8. Optimisation of secondary electrospray ionisation (SESI) for the trace determination of gas-phase volatile organic compounds.

    Science.gov (United States)

    Dillon, Leonard A; Stone, Victoria N; Croasdell, Laura A; Fielden, Peter R; Goddard, Nicholas J; Thomas, C L Paul

    2010-02-01

    An electrospray ionisation triple quadrupole mass spectrometer (Varian 1200 L) was modified to accept nitrogen samples containing low concentrations of volatile organic compounds. Six candidate probe compounds, methyl decanoate, octan-3-one, 2-ethylhexanoic acid, 1,4-diaminobutane, dimethyl methylphosphonate, and 2,3-butanediol, at concentrations below 50 ppb(v) were generated with permeation tubes in a test atmosphere generator. The concept of using a set of molecular probes to evaluate gas-phase electrospray ionisation of volatile analytes was assessed and the feasibility of adopting a unified ionisation approach for gas and liquid contamination of exobiotic environments established. 450 experiments were run in a five-replicate, fifteen-level, three-factor, central-composite-design with exponential dilution for each of the six probe compounds studied. The three factors studied were ionisation voltage, drying-gas flow and nebulising-gas flow. Parametric modelling by regression analysis enabled the differences in the ionisation behaviours of the probe compounds to be described by the optimisation models. Regression coefficients were in the range 0.91 to 0.99, indicating satisfactory levels of precision in the optimisation models. A wide range in ionisation efficiency was observed, with different optimised conditions required for the probe compounds. It was evident that no one factor appeared to dominate the response and the different factors produced different effects on the responses for the different molecules. 1,4-Butanediamine and dimethyl methylphosphonate required significantly lower ionisation voltages (1.2 kV) than the other four, which achieved optimised sensitivity towards the maximum voltage used in this design (5 to 6 kV). Drying-gas flow rates were found to be more important than nebulising-gas flow rates. However, variations in the constant term B(0) in the optimisation models indicated that other factors, not included in this study, were also likely

  9. DEVELOPMENT OF MICROORGANISMS WITH IMPROVED TRANSPORT AND BIOSURFACTANT ACTIVITY FOR ENHANCED OIL RECOVERY

    Energy Technology Data Exchange (ETDEWEB)

    M.J. McInerney; R.M. Knapp; D.P. Nagle, Jr.; Kathleen Duncan; N. Youssef; M.J. Folmsbee; S. Maudgakya

    2003-06-26

    Biosurfactants enhance hydrocarbon biodegradation by increasing apparent aqueous solubility or affecting the association of the cell with poorly soluble hydrocarbon. Here, we show that a lipopeptide biosurfactant produced by Bacillus mojavensis strain JF-2 mobilized substantial amounts of residual hydrocarbon from sand-packed columns when a viscosifying agent and a low molecular weight alcohol were present. The amount of residual hydrocarbon mobilized depended on the biosurfactant concentration. One pore volume of cell-free culture fluid with 900 mg/l of the biosurfactant, 10 mM 2,3-butanediol and 1000 mg/l of partially hydrolyzed polyacrylamide polymer mobilized 82% of the residual hydrocarbon. Consistent with the high residual oil recoveries, we found that the bio-surfactant lowered the interfacial tension (IFT) between oil and water by nearly 2 orders of magnitude compared to typical IFT values of 28-29 mN/m. Increasing the salinity increased the IFT with or without 2,3-butanediol present. The lowest interfacial tension observed was 0.1 mN/m. The lipopeptide biosurfactant system may be effective in removing hydrocarbon contamination sources in soils and aquifers and for the recovery of entrapped oil from low production oil reservoirs. Previously, we reported that Proteose peptone was necessary for anaerobic growth and biosurfactant production by B. mojavensis JF-2. The data gathered from crude purification of the growth-enhancing factor in Proteose peptone suggested that it consisted of nucleic acids; however, nucleic acid bases, nucleotides or nucleosides did not replace the requirement for Proteose Peptone. Further studies revealed that salmon sperm DNA, herring sperm DNA, Echerichia coli DNA and synthetic DNA replaced the requirement for Proteose peptone. In addition to DNA, amino acids and nitrate were required for anaerobic growth and vitamins further improved growth. We now have a defined medium that can be used to manipulate growth and biosurfactant

  10. Response of the cytoplasmic and membrane proteome of Corynebacterium glutamicum ATCC 13032 to pH changes

    Directory of Open Access Journals (Sweden)

    Poetsch Ansgar

    2008-12-01

    Full Text Available Abstract Background C. glutamicum has traditionally been grown in neutral-pH media for amino acid production, but in a previous article we reported that this microorganism is a moderate alkaliphile since it grows optimally at pH 7.0–9.0, as shown in fermentor studies under tightly controlled pH conditions. We determined the best pH values to study differential expression of several genes after acidic or basic pH conditions (pH 6.0 for acidic expression and pH 9.0 for alkaline expression. Thus, it was interesting to perform a detailed analysis of the pH-adaptation response of the proteome of C. glutamicum ATCC 13032 to clarify the circuits involved in stress responses in this bacterium. In this paper we used the above indicated pH conditions, based on transcriptional studies, to confirm that pH adaptation results in significant changes in cytoplasmatic and membrane proteins. Results The cytoplasmatic and membrane proteome of Corynebacterium glutamicum ATCC 13032 at different pH conditions (6.0, 7.0 and 9.0 was analyzed by classical 2D-electrophoresis, and by anion exchange chromatography followed by SDS-PAGE (AIEC/SDS-PAGE. A few cytoplasmatic proteins showed differential expression at the three pH values with the classical 2D-technique including a hypothetical protein cg2797, L-2.3-butanediol dehydrogenase (ButA, and catalase (KatA. The AIEC/SDS-PAGE technique revealed several membrane proteins that respond to pH changes, including the succinate dehydrogenase complex (SdhABCD, F0F1-ATP synthase complex subunits b, α and δ (AtpF, AtpH and AtpA, the nitrate reductase II α subunit (NarG, and a hypothetical secreted/membrane protein cg0752. Induction of the F0F1-ATP synthase complex β subunit (AtpD at pH 9.0 was evidenced by Western analysis. By contrast, L-2.3-butanediol dehydrogenase (ButA, an ATPase with chaperone activity, the ATP-binding subunit (ClpC of an ATP-dependent protease complex, a 7 TMHs hypothetical protein cg0896, a conserved

  11. The {gamma} radiolysis at room temperature of liquid deaerated isopropanol; Radiolyse {gamma} a temperature ambiante de l'isopropanol liquide desaere

    Energy Technology Data Exchange (ETDEWEB)

    Gilles, L. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-02-01

    The main products formed in the room temperature {gamma} radiolysis of liquid isopropanol, and their respective yields, are: hydrogen 3.8, methane 1.6, acetone 3.4, acetaldehyde 1.1, and pinacol 0.3. These results give a material balance in good agreement with the formula of isopropanol and lead to a value for the yield of decomposition: 5, 3. The absence of butanediol 2.3 shows that the acetaldehyde cannot come from the dismutation of hydroxyethyl radicals. The variations of the hydrogen yield in the neutral medium with the concentration of added electron scavengers may be explained in terms of the model proposed by Freeman and FAYADH which supposes the existence of spurs. The yield of solvated electrons diffusing into the bulk of the solution and also the ratios of rate constants for the reactions of the scavengers with the electrons may likewise be obtained on the basis of this model. Certain effects not foreseen by this model may result from the capture of electrons solvated or not, whose mode of disappearance in pure alcohol remains unknown. One may distinguish a yield of excited molecules of at least 2, of which 80 per cent lead to the production of molecular hydrogen and 20 per cent to that of molecular methane, and an ionization yield of 2. 2. The discussion of the various mechanisms which may lead to the formation of the products indicates that these yields may be higher than the values quoted. (author) [French] Les principaux produits formes a temperature ambiante dans la radiolyse {gamma} de l'isopropanol liquide sont: l'hydrogene, le methane, l'acetone, l'acetaldehyde et le pinacol avec des rendements respectifs de 3,8 - 1,6 - 3,4 - 1,1 - 0,3. Le bilan de masse deduit de ces resultats est en bon accord avec la formule brute de l'isopropanol dont le rendement de decomposition est 5,3. L'absence de butanediol 2,3 montre que l'acetaldehyde ne peut provenir de la reaction de dismutation des radicaux hydroxyethyles. Le

  12. The effect of organic acids and sulfur dioxide on C4 compound production and β-glucosidase activity of Oenococcus oeni from wines under acidic conditions

    Directory of Open Access Journals (Sweden)

    Maturano C

    2016-09-01

    Full Text Available Carmen Maturano,1 Luciana del Valle Rivero,2 María José Rodríguez Vaquero,2 Fabiana María Saguir2 1Institute for Research and Development in Process Engineering, Biotechnology and Alternative Energy (PROBIEN, CONICET, Faculty of Engineering, National University of Comahue, Neuquén, 2Institute of Microbiology, Faculty of Biochemistry, Chemistry and Pharmacy, National University of Tucuman, Tucumán, Argentina Abstract: The purpose of this work was to investigate the effect of l-malic and citric acids and SO2 on two biochemical properties (diacetyl/acetoin/2,3-butanediol formation and β-glucosidase activity relevant to flavor development in six Oenococcus oeni strains from wines at pH 4.8 and 3.8. Cells were cultured in MRS without citrate (control medium and combined with l-malic acid (2 g/L, citric acid (0.7 g/L, and SO2 (80 mg/L at pH 4.8 and 3.8. All the test strains grew at all conditions tested including in the presence of SO2 and at initial pH 3.8, even though growth parameters were maximum in the presence of both the acids at pH 4.8. Organic acids were depleted totally regardless of the condition examined, in which degradation of l-malic acid was faster than that of citric acid. Diacetyl, acetoin, and 2,3-butanediol levels significantly varied depending on the strain for a given condition, for example, at pH 4.8 in control medium the highest value (6.55±0.31 mg/L, strain MS25 represented almost threefold the lowest one (2.43±0.22 mg/L, strain MS9. There was also variability for each strain depending on the initial pH (strains MS25, MS27, and MS48 and the presence of organic acids (all strains except MS25 but not SO2. In addition, among strains there was a trend toward mainly diacetyl formation (55%–75%. O. oeni MS9, MS20, and MS46 yielding adequate diacetyl levels were selected for investigating specific β-glucosidase activity and its possible cell localization. Cell suspensions of all the selected strains exhibited positive

  13. Whole genome sequencing and analysis of plant growth promoting bacteria isolated from the rhizosphere of plantation crops coconut, cocoa and arecanut.

    Science.gov (United States)

    Gupta, Alka; Gopal, Murali; Thomas, George V; Manikandan, Vinu; Gajewski, John; Thomas, George; Seshagiri, Somasekar; Schuster, Stephan C; Rajesh, Preeti; Gupta, Ravi

    2014-01-01

    Coconut, cocoa and arecanut are commercial plantation crops that play a vital role in the Indian economy while sustaining the livelihood of more than 10 million Indians. According to 2012 Food and Agricultural organization's report, India is the third largest producer of coconut and it dominates the production of arecanut worldwide. In this study, three Plant Growth Promoting Rhizobacteria (PGPR) from coconut (CPCRI-1), cocoa (CPCRI-2) and arecanut (CPCRI-3) characterized for the PGP activities have been sequenced. The draft genome sizes were 4.7 Mb (56% GC), 5.9 Mb (63.6% GC) and 5.1 Mb (54.8% GB) for CPCRI-1, CPCRI-2, CPCRI-3, respectively. These genomes encoded 4056 (CPCRI-1), 4637 (CPCRI-2) and 4286 (CPCRI-3) protein-coding genes. Phylogenetic analysis revealed that both CPCRI-1 and CPCRI-3 belonged to Enterobacteriaceae family, while, CPCRI-2 was a Pseudomonadaceae family member. Functional annotation of the genes predicted that all three bacteria encoded genes needed for mineral phosphate solubilization, siderophores, acetoin, butanediol, 1-aminocyclopropane-1-carboxylate (ACC) deaminase, chitinase, phenazine, 4-hydroxybenzoate, trehalose and quorum sensing molecules supportive of the plant growth promoting traits observed in the course of their isolation and characterization. Additionally, in all the three CPCRI PGPRs, we identified genes involved in synthesis of hydrogen sulfide (H2S), which recently has been proposed to aid plant growth. The PGPRs also carried genes for central carbohydrate metabolism indicating that the bacteria can efficiently utilize the root exudates and other organic materials as energy source. Genes for production of peroxidases, catalases and superoxide dismutases that confer resistance to oxidative stresses in plants were identified. Besides these, genes for heat shock tolerance, cold shock tolerance and glycine-betaine production that enable bacteria to survive abiotic stress were also identified.

  14. Utilizing peptidic ordering in the design of hierarchical polyurethane/ureas.

    Science.gov (United States)

    Johnson, J Casey; Wanasekara, Nandula D; Korley, Lashanda T J

    2012-05-14

    One of the key design components of nature is the utilization of hierarchical arrangements to fabricate materials with outstanding mechanical properties. Employing the concept of hierarchy, a new class of segmented polyurethane/ureas (PUUs) was synthesized containing either a peptidic, triblock soft segment, or an amorphous, nonpeptidic homoblock block soft segment with either an amorphous or a crystalline hard segment to investigate the effects of bioinspired, multiple levels of organization on thermal and mechanical properties. The peptidic soft segment was composed of poly(benzyl-l-glutamate)-block-poly(dimethylsiloxane)-block-poly(benzyl-l-glutamate) (PBLG-b-PDMS-b-PBLG), restricted to the β-sheet conformation by limiting the peptide segment length to <10 residues, whereas the amorphous soft segment was poly(dimethylsiloxane) (PDMS). The hard segment consisted of either 1,6-hexamethylene diisocyanate (crystalline) or isophorone diisocyanate (amorphous) and chain extended with 1,4-butanediol. Thermal and morphological characterization indicated microphase separation in these hierarchically assembled PUUs; furthermore, inclusion of the peptidic segment significantly increased the average long spacing between domains, whereas the peptide domain retained its β-sheet conformation regardless of the hard segment chemistry. Mechanical analysis revealed an enhanced dynamic modulus for the peptidic polymers over a broader temperature range as compared with the nonpeptidic PUUs as well as an over three-fold increase in tensile modulus. However, the elongation-at-break was dramatically reduced, which was attributed to a shift from a flexible, continuous domain morphology to a rigid, continuous matrix in which the peptide, in conjunction with the hard segment, acts as a stiff reinforcing element.

  15. Magnetic properties evolution of the Co{sub x}Fe{sub 3-x}O{sub 4}/SiO{sub 2} system due to advanced thermal treatment at 700 °C and 1000 °C

    Energy Technology Data Exchange (ETDEWEB)

    Dippong, Thomas, E-mail: dippong.thomas@yahoo.ro [Technical University of Cluj-Napoca, North University Center of Baia Mare, Department of Chemistry and Biology, 76 Victoriei Street, 430122 Baia Mare (Romania); Levei, Erika Andrea, E-mail: erika.levei@icia.ro [INCDO-INOE 2000, Research Institute for Analytical Instrumentation, 67 Donath Street, 400293 Cluj-Napoca (Romania); Tanaselia, Claudiu [INCDO-INOE 2000, Research Institute for Analytical Instrumentation, 67 Donath Street, 400293 Cluj-Napoca (Romania); Gabor, Mihai, E-mail: mihai.gabor@phys.utcluj.ro [Technical University of Cluj-Napoca, Physics and Chemistry Department, Center for Superconductivity, Spintronics and Surface Science, 28 Memorandumului Street, 400114 Cluj-Napoca (Romania); Nasui, Mircea [Technical University of Cluj-Napoca, Physics and Chemistry Department, Center for Superconductivity, Spintronics and Surface Science, 28 Memorandumului Street, 400114 Cluj-Napoca (Romania); Barbu Tudoran, Lucian, E-mail: lbarbu@hasdeu.ubbcluj.ro [Babes-Bolyai University, Faculty of Biology and Geology, 44 Bilascu Street, 400015 Cluj-Napoca (Romania); Borodi, Gheorghe, E-mail: borodi@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath Street, 400293 Cluj-Napoca (Romania)

    2016-07-15

    The Co{sub x}Fe{sub 3−x}O{sub 4} (x=0.5–2.5) system embedded in the silica matrix was synthesised by sol–gel method using cobalt nitrate, iron nitrate, 1.4-butanediol and tetraethyl orthosilicate. Five different Co/Fe molar ratios in the presence of diol and one without diol were used for the synthesis. The obtained gels were subjected to thermal treatment at 700 °C and 1000 °C. The oxide species formed in the silica matrix, the optimum temperature for the CoFe{sub 2}O{sub 4} phase formation, the evolution of nanocrystallites size and magnetic properties with the calcination temperature were studied. The formed oxide species were studied using X-ray diffraction, Fourier transformed infrared spectrometry, the Co/Fe molar ratio was confirmed using inductively coupled plasma optical emission spectrometry, the nanocrystallites size, shape and clustering was identified by transmission electron microscopy and scanning electron microscopy, while the formation of magnetic phases was investigated by hysteresis and magnetization derivatives measurements. - Highlights: • Co{sub x}Fe{sub 3−x}O{sub 4} (x=0.5–2.5) system embedded in the silica matrix was synthesised. • The CoFe{sub 2}O{sub 4} was obtained as single magnetic phase. • The saturation magnetization decrease with the increase of the Co/Fe ratio. • Magnetization increase and coercive field decrease with the calcination temperature. • The CoFe{sub 2}O{sub 4} crystallite size increase from 5–10.3 nm (700 °C) to 9–34 nm (1000 °C).

  16. Polymeric nanoparticles for nonviral gene therapy extend brain tumor survival in vivo.

    Science.gov (United States)

    Mangraviti, Antonella; Tzeng, Stephany Yi; Kozielski, Kristen Lynn; Wang, Yuan; Jin, Yike; Gullotti, David; Pedone, Mariangela; Buaron, Nitsa; Liu, Ann; Wilson, David R; Hansen, Sarah K; Rodriguez, Fausto J; Gao, Guo-Dong; DiMeco, Francesco; Brem, Henry; Olivi, Alessandro; Tyler, Betty; Green, Jordan J

    2015-02-24

    Biodegradable polymeric nanoparticles have the potential to be safer alternatives to viruses for gene delivery; however, their use has been limited by poor efficacy in vivo. In this work, we synthesize and characterize polymeric gene delivery nanoparticles and evaluate their efficacy for DNA delivery of herpes simplex virus type I thymidine kinase (HSVtk) combined with the prodrug ganciclovir (GCV) in a malignant glioma model. We investigated polymer structure for gene delivery in two rat glioma cell lines, 9L and F98, to discover nanoparticle formulations more effective than the leading commercial reagent Lipofectamine 2000. The lead polymer structure, poly(1,4-butanediol diacrylate-co-4-amino-1-butanol) end-modified with 1-(3-aminopropyl)-4-methylpiperazine, is a poly(β-amino ester) (PBAE) and formed nanoparticles with HSVtk DNA that were 138 ± 4 nm in size and 13 ± 1 mV in zeta potential. These nanoparticles containing HSVtk DNA showed 100% cancer cell killing in vitro in the two glioma cell lines when combined with GCV exposure, while control nanoparticles encoding GFP maintained robust cell viability. For in vivo evaluation, tumor-bearing rats were treated with PBAE/HSVtk infusion via convection-enhanced delivery (CED) in combination with systemic administration of GCV. These treated animals showed a significant benefit in survival (p = 0.0012 vs control). Moreover, following a single CED infusion, labeled PBAE nanoparticles spread completely throughout the tumor. This study highlights a nanomedicine approach that is highly promising for the treatment of malignant glioma.

  17. Complete genome sequence of Corynebacterium variabile DSM 44702 isolated from the surface of smear-ripened cheeses and insights into cheese ripening and flavor generation

    Directory of Open Access Journals (Sweden)

    Trost Eva

    2011-11-01

    Full Text Available Abstract Background Corynebacterium variabile is part of the complex microflora on the surface of smear-ripened cheeses and contributes to the development of flavor and textural properties during cheese ripening. Still little is known about the metabolic processes and microbial interactions during the production of smear-ripened cheeses. Therefore, the gene repertoire contributing to the lifestyle of the cheese isolate C. variabile DSM 44702 was deduced from the complete genome sequence to get a better understanding of this industrial process. Results The chromosome of C. variabile DSM 44702 is composed of 3, 433, 007 bp and contains 3, 071 protein-coding regions. A comparative analysis of this gene repertoire with that of other corynebacteria detected 1, 534 predicted genes to be specific for the cheese isolate. These genes might contribute to distinct metabolic capabilities of C. variabile, as several of them are associated with metabolic functions in cheese habitats by playing roles in the utilization of alternative carbon and sulphur sources, in amino acid metabolism, and fatty acid degradation. Relevant C. variabile genes confer the capability to catabolize gluconate, lactate, propionate, taurine, and gamma-aminobutyric acid and to utilize external caseins. In addition, C. variabile is equipped with several siderophore biosynthesis gene clusters for iron acquisition and an exceptional repertoire of AraC-regulated iron uptake systems. Moreover, C. variabile can produce acetoin, butanediol, and methanethiol, which are important flavor compounds in smear-ripened cheeses. Conclusions The genome sequence of C. variabile provides detailed insights into the distinct metabolic features of this bacterium, implying a strong adaption to the iron-depleted cheese surface habitat. By combining in silico data obtained from the genome annotation with previous experimental knowledge, occasional observations on genes that are involved in the complex

  18. Whole genome sequencing and analysis of plant growth promoting bacteria isolated from the rhizosphere of plantation crops coconut, cocoa and arecanut.

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    Alka Gupta

    Full Text Available Coconut, cocoa and arecanut are commercial plantation crops that play a vital role in the Indian economy while sustaining the livelihood of more than 10 million Indians. According to 2012 Food and Agricultural organization's report, India is the third largest producer of coconut and it dominates the production of arecanut worldwide. In this study, three Plant Growth Promoting Rhizobacteria (PGPR from coconut (CPCRI-1, cocoa (CPCRI-2 and arecanut (CPCRI-3 characterized for the PGP activities have been sequenced. The draft genome sizes were 4.7 Mb (56% GC, 5.9 Mb (63.6% GC and 5.1 Mb (54.8% GB for CPCRI-1, CPCRI-2, CPCRI-3, respectively. These genomes encoded 4056 (CPCRI-1, 4637 (CPCRI-2 and 4286 (CPCRI-3 protein-coding genes. Phylogenetic analysis revealed that both CPCRI-1 and CPCRI-3 belonged to Enterobacteriaceae family, while, CPCRI-2 was a Pseudomonadaceae family member. Functional annotation of the genes predicted that all three bacteria encoded genes needed for mineral phosphate solubilization, siderophores, acetoin, butanediol, 1-aminocyclopropane-1-carboxylate (ACC deaminase, chitinase, phenazine, 4-hydroxybenzoate, trehalose and quorum sensing molecules supportive of the plant growth promoting traits observed in the course of their isolation and characterization. Additionally, in all the three CPCRI PGPRs, we identified genes involved in synthesis of hydrogen sulfide (H2S, which recently has been proposed to aid plant growth. The PGPRs also carried genes for central carbohydrate metabolism indicating that the bacteria can efficiently utilize the root exudates and other organic materials as energy source. Genes for production of peroxidases, catalases and superoxide dismutases that confer resistance to oxidative stresses in plants were identified. Besides these, genes for heat shock tolerance, cold shock tolerance and glycine-betaine production that enable bacteria to survive abiotic stress were also identified.

  19. Proteins involved in wine aroma compounds metabolism by a Saccharomyces cerevisiae flor-velum yeast strain grown in two conditions.

    Science.gov (United States)

    Moreno-García, Jaime; García-Martínez, Teresa; Millán, M Carmen; Mauricio, Juan Carlos; Moreno, Juan

    2015-10-01

    A proteomic and exometabolomic study was conducted on Saccharomyces cerevisiae flor yeast strain growing under biofilm formation condition (BFC) with ethanol and glycerol as carbon sources and results were compared with those obtained under no biofilm formation condition (NBFC) containing glucose as carbon source. By using modern techniques, OFFGEL fractionator and LTQ-Orbitrap for proteome and SBSE-TD-GC-MS for metabolite analysis, we quantified 84 proteins including 33 directly involved in the metabolism of glycerol, ethanol and 17 aroma compounds. Contents in acetaldehyde, acetic acid, decanoic acid, 1,1-diethoxyethane, benzaldehyde and 2-phenethyl acetate, changed above their odor thresholds under BFC, and those of decanoic acid, ethyl octanoate, ethyl decanoate and isoamyl acetate under NBFC. Of the twenty proteins involved in the metabolism of ethanol, acetaldehyde, acetoin, 2,3-butanediol, 1,1-diethoxyethane, benzaldehyde, organic acids and ethyl esters, only Adh2p, Ald4p, Cys4p, Fas3p, Met2p and Plb1p were detected under BFC and as many Acs2p, Ald3p, Cem1p, Ilv2p, Ilv6p and Pox1p, only under NBFC. Of the eight proteins involved in glycerol metabolism, Gut2p was detected only under BFC while Pgs1p and Rhr2p were under NBFC. Finally, of the five proteins involved in the metabolism of higher alcohols, Thi3p was present under BFC, and Aro8p and Bat2p were under NBFC. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Comparative study of aromatic compounds in fruit wines from raspberry, strawberry, and mulberry in central Shaanxi area

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    Yiming Feng

    2015-11-01

    Full Text Available Background: Although grape wines have firmly dominated the production and consumption markets of fruit wines, raspberry, strawberry, and mulberry have been utilized to make wines because of their joyful aroma and high contents of polyphenolic phytochemicals and essential fatty acids. However, little is known about aromatic compounds of the wines produced from these three fruits. Methods: The aromatic composition of fruit wines produced from raspberry, strawberry, mulberry, and red grape was analyzed by GC-MS. Odor activity values (OAVs and relative odor contributions (ROCs were used to estimate the sensory contribution of the aromatic compounds to the overall flavor of the wines. Results: In strawberry, raspberry, and mulberry wines, 27, 30, and 31 odorants were detected, respectively. Alcohols formed the most abundant group, followed by esters and acids. The grape wine contained a wider variety (16 types of alcohols, and 4-methyl-2-pentanol and 2,3-butanediol were not present in the three fruit wines. The quantity of esters in raspberry (1.54% and mulberry wines (2.08% were higher than those of strawberry wine (0.78%, and mulberry wine contained more types of esters. There were no significant differences of acids between the three fruit wines and the control wine. In addition, 2-heptanone, 2-octanone, 2-nonanone, and 2-undecanone were unique to raspberry wine, and nonanal was present only in mulberry wine. The indistinguishable aroma of the three fruit wines was attributed to the dominance of fruity and floral odor components derived from ethyl esters of fatty acids and their contributions to the global aroma of the three fruit wines. Conclusion: The present study demonstrated that there were significant differences in the volatile components of fruit wines made from raspberry, strawberry, and mulberry. The aroma compounds were more abundant in the raspberry and mulberry wines than in the strawberry wine, but the quality of strawberry wine was

  1. Effect of replacing polyol by organosolv and kraft lignin on the property and structure of rigid polyurethane foam

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    Pan Xuejun

    2013-01-01

    Full Text Available Abstract Background Lignin is one of the three major components in plant cell walls, and it can be isolated (dissolved from the cell wall in pretreatment or chemical pulping. However, there is a lack of high-value applications for lignin, and the commonest proposal for lignin is power and steam generation through combustion. Organosolv ethanol process is one of the effective pretreatment methods for woody biomass for cellulosic ethanol production, and kraft process is a dominant chemical pulping method in paper industry. In the present research, the lignins from organosolv pretreatment and kraft pulping were evaluated to replace polyol for producing rigid polyurethane foams (RPFs. Results Petroleum-based polyol was replaced with hardwood ethanol organosolv lignin (HEL or hardwood kraft lignin (HKL from 25% to 70% (molar percentage in preparing rigid polyurethane foam. The prepared foams contained 12-36% (w/w HEL or 9-28% (w/w HKL. The density, compressive strength, and cellular structure of the prepared foams were investigated and compared. Chain extenders were used to improve the properties of the RPFs. Conclusions It was found that lignin was chemically crosslinked not just physically trapped in the rigid polyurethane foams. The lignin-containing foams had comparable structure and strength up to 25-30% (w/w HEL or 19-23% (w/w HKL addition. The results indicated that HEL performed much better in RPFs and could replace more polyol at the same strength than HKL because the former had a better miscibility with the polyol than the latter. Chain extender such as butanediol could improve the strength of lignin-containing RPFs.

  2. Non-isothermal crystallization kinetics and characterization of biodegradable poly(butylene succinate-co-neopentyl glycol succinate) copolyesters.

    Science.gov (United States)

    Xie, Wen-Jie; Zhou, Xiao-Ming

    2015-01-01

    Both biodegradable aliphatic neat poly(butylene succinate) (PBS) and poly(butylene succinate-co-neopentyl glycol succinate) (P(BS-co-NPGS)) copolyesters with different 1,4-butanediol/neopentyl glycol ratios were synthesized through a two-step process of transesterification and polycondensation using stannous chloride and 4-Methylbenzenesulfonic acid as the co-catalysts. The structure, non-isothermal crystallization behavior, crystalline morphology and crystal structure of neat PBS and P(BS-co-NPGS) copolyesters were characterized by (1)H NMR, differential scanning calorimetry (DSC), polarized optical microscope (POM) and wide angle X-ray diffraction (WAXD), respectively. The Avrami equation modified by Jeziorny and Mo's method was employed to describe the non-isothermal crystallization kinetics of the neat PBS and its copolyesters. The modified Avrami equation could adequately describe the primary stage of non-isothermal crystallization kinetics of the neat PBS and its copolyesters. Mo's method provided a fairly satisfactory description of the non-isothermal crystallization of neat PBS and its copolyesters. Interestingly, the values of 1/t1/2, Zc and F(T) obtained by the modified Avrami equation and Mo's method analysis indicated that the crystallization rate increased first and then decreased with an increase of NPGS content compared that of neat PBS, whereas the crystallization mechanism almost kept unchanged. The results of tensile testing showed that the ductility of PBS was largely improved by incorporating NPGS units. The elongation at break increased remarkably with increasing NPGS content. In particular, the sample with 20% NPGS content showed around 548% elongation at break. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Quantitative Analysis of Humectants in Tobacco Products Using Gas Chromatography (GC with Simultaneous Mass Spectrometry (MSD and Flame Ionization Detection (FID

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    Rainey CL

    2014-12-01

    Full Text Available This paper describes the modification of an existing gas chromatographic (GC method to incorporate simultaneous mass spectrometric (MSD and flame ionization detection (FID into the analysis of tobacco humectants. Glycerol, propylene glycol, and triethylene glycol were analyzed in tobacco labeled as roll-your-own (RYO, cigar, cigarette, moist snuff, and hookah tobacco. Tobacco was extracted in methanol containing 1,3-butanediol (internal standard, filtered, and separated on a 15 m megabore DB-Wax column. Post-column flow was distributed using a microfluidic splitter between the MSD and FID for simultaneous detection. The limits of detection for the FID detector were 0.5 μg/mL (propylene glycol and triethylene glycol and 0.25 μg/mL (glycerol with a linear range of 2-2000 μg/mL (propylene glycol and triethylene glycol and 1-4000 μg/mL (glycerol. The limits of detection for the MSD detector were 2 μg/mL (propylene glycol and triethylene glycol and 4 μg/mL (glycerol with a linear range of 20-2000 μg/mL (propylene glycol and triethylene glycol and 40-4000 μg/mL (glycerol. Significant improvement in the sensitivity of the MSD can be achieved by employing selective ion monitoring (SIM detection mode. Although a high degree of correlation was observed between the results from FID and MSD analyses, marginal chromatographic resolution between glycerol and triethylene glycol limits the applicability of FID to samples containing low levels of both of these humectants. Utilizing MSD greatly improves the reliability of quantitative results because compensation for inadequate chromatographic resolution can be accomplished with mass selectivity in detection.

  4. Effect of ether glycerol lipids on interleukin-1β release and experimental autoimmune encephalomyelitis.

    Science.gov (United States)

    Boomkamp, Stephanie D; Byun, Hoe-Sup; Ubhi, Satvir; Jiang, Hui-Rong; Pyne, Susan; Bittman, Robert; Pyne, Nigel J

    2016-01-01

    We have assessed the effect of two ether glycerol lipids, 77-6 ((2S, 3R)-4-(Tetradecyloxy)-2-amino-1,3-butanediol) and 56-5 ((S)-2-Amino-3-O-hexadecyl-1-propanol), which are substrates for sphingosine kinases, on inflammatory responses. Treatment of differentiated U937 macrophage-like cells with 77-6 but not 56-5 enhanced IL-1β release; either alone or in the presence of LPS. The stimulatory effect of sphingosine or 77-6 on LPS-stimulated IL-1β release was reduced by pretreatment of cells with the caspase-1 inhibitor, Ac-YVAD-CHO, thereby indicating a role for the inflammasome. The enhancement of LPS-stimulated IL-1β release in response to sphingosine, but not 77-6, was reduced by pretreatment of cells with the cathepsin B inhibitor, CA074Me, indicating a role for lysosomal destabilization in the effect of sphingosine. Administration of 56-5 to mice increased disease progression in an experimental autoimmune encephalomyelitis model and this was associated with a considerable increase in the infiltration of CD4(+) T-cells, CD11b(+) monocytes and F4/80(+) macrophages in the spinal cord. 56-5 and 77-6 were without effect on the degradation of myc-tagged sphingosine 1-phosphate 1 receptor in CCL39 cells. Therefore, the effect of 56-5 on EAE disease progression is likely to be independent of the inflammasome or the sphingosine 1-phosphate 1 receptor. However, 56-5 is chemically similar to platelet activating factor and the exacerbation of EAE disease progression might be linked to platelet activating factor receptor signaling. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

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

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    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.

  6. Biodegradable polyesters based on succinic acid

    Directory of Open Access Journals (Sweden)

    Nikolić Marija S.

    2003-01-01

    Full Text Available Two series of aliphatic polyesters based on succinic acid were synthesized by copolymerization with adipic acid for the first series of saturated polyesters, and with fumaric acid for the second series. Polyesters were prepared starting from the corresponding dimethyl esters and 1,4-butanediol by melt transesterification in the presence of a highly effective catalyst tetra-n-butyl-titanate, Ti(0Bu4. The molecular structure and composition of the copolyesters was determined by 1H NMR spectroscopy. The effect of copolymer composition on the physical and thermal properties of these random polyesters were investigated using differential scanning calorimetry. The degree of crystallinity was determined by DSC and wide angle X-ray. The degrees of crystallinity of the saturated and unsaturated copolyesters were generally reduced with respect to poly(butylene succinate, PBS. The melting temperatures of the saturated polyesters were lower, while the melting temperatures of the unsaturated copolyesters were higher than the melting temperature of PBS. The biodegradability of the polyesters was investigated by enzymatic degradation tests. The enzymatic degradation tests were performed in a buffer solution with Candida cylindracea lipase and for the unsaturated polyesters with Rhizopus arrhizus lipase. The extent of biodegradation was quantified as the weight loss of polyester films. Also the surface of the polyester films after degradation was observed using optical microscopy. It could be concluded that the biodegradability depended strongly on the degree of crystallinity, but also on the flexibility of the chain backbone. The highest biodegradation was observed for copolyesters containing 50 mol.% of adipic acid units, and in the series of unsaturated polyesters for copolyesters containing 5 and 10 mol.% of fumarate units. Although the degree of crystallinity of the unsaturated polyesters decreased slightly with increasing unsaturation, the biodegradation

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

    Science.gov (United States)

    Debuissy, Thibaud; Pollet, Eric; Avérous, Luc

    2016-12-12

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

  8. Alcohol based-deep eutectic solvent (DES) as an alternative green additive to increase rotenone yield

    Energy Technology Data Exchange (ETDEWEB)

    Othman, Zetty Shafiqa; Hassan, Nur Hasyareeda; Zubairi, Saiful Irwan [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia)

    2015-09-25

    Deep eutectic solvents (DESs) are basically molten salts that interact by forming hydrogen bonds between two added components at a ratio where eutectic point reaches a melting point lower than that of each individual component. Their remarkable physicochemical properties (similar to ionic liquids) with remarkable green properties, low cost and easy handling make them a growing interest in many fields of research. Therefore, the objective of pursuing this study is to analyze the potential of alcohol-based DES as an extraction medium for rotenone extraction from Derris elliptica roots. DES was prepared by a combination of choline chloride, ChCl and 1, 4-butanediol at a ratio of 1/5. The structure of elucidation of DES was analyzed using FTIR, {sup 1}H-NMR and {sup 13}C-NMR. Normal soaking extraction (NSE) method was carried out for 14 hours using seven different types of solvent systems of (1) acetone; (2) methanol; (3) acetonitrile; (4) DES; (5) DES + methanol; (6) DES + acetonitrile; and (7) [BMIM] OTf + acetone. Next, the yield of rotenone, % (w/w), and its concentration (mg/ml) in dried roots were quantitatively determined by means of RP-HPLC. The results showed that a binary solvent system of [BMIM] OTf + acetone and DES + acetonitrile was the best solvent system combination as compared to other solvent systems. It contributed to the highest rotenone content of 0.84 ± 0.05% (w/w) (1.09 ± 0.06 mg/ml) and 0.84 ± 0.02% (w/w) (1.03 ± 0.01 mg/ml) after 14 hours of exhaustive extraction time. In conclusion, a combination of the DES with a selective organic solvent has been proven to have a similar potential and efficiency as of ILs in extracting bioactive constituents in the phytochemical extraction process.

  9. The exometabolome of Clostridium thermocellum reveals overflow metabolism at high cellulose loading.

    Science.gov (United States)

    Holwerda, Evert K; Thorne, Philip G; Olson, Daniel G; Amador-Noguez, Daniel; Engle, Nancy L; Tschaplinski, Timothy J; van Dijken, Johannes P; Lynd, Lee R

    2014-01-01

    Clostridium thermocellum is a model thermophilic organism for the production of biofuels from lignocellulosic substrates. The majority of publications studying the physiology of this organism use substrate concentrations of ≤10 g/L. However, industrially relevant concentrations of substrate start at 100 g/L carbohydrate, which corresponds to approximately 150 g/L solids. To gain insight into the physiology of fermentation of high substrate concentrations, we studied the growth on, and utilization of high concentrations of crystalline cellulose varying from 50 to 100 g/L by C. thermocellum. Using a defined medium, batch cultures of C. thermocellum achieved 93% conversion of cellulose (Avicel) initially present at 100 g/L. The maximum rate of substrate utilization increased with increasing substrate loading. During fermentation of 100 g/L cellulose, growth ceased when about half of the substrate had been solubilized. However, fermentation continued in an uncoupled mode until substrate utilization was almost complete. In addition to commonly reported fermentation products, amino acids - predominantly L-valine and L-alanine - were secreted at concentrations up to 7.5 g/L. Uncoupled metabolism was also accompanied by products not documented previously for C. thermocellum, including isobutanol, meso- and RR/SS-2,3-butanediol and trace amounts of 3-methyl-1-butanol, 2-methyl-1-butanol and 1-propanol. We hypothesize that C. thermocellum uses overflow metabolism to balance its metabolism around the pyruvate node in glycolysis. C. thermocellum is able to utilize industrially relevant concentrations of cellulose, up to 93 g/L. We report here one of the highest degrees of crystalline cellulose utilization observed thus far for a pure culture of C. thermocellum, the highest maximum substrate utilization rate and the highest amount of isobutanol produced by a wild-type organism.

  10. Thermal expansion of the cryoprotectant cocktail DP6 combined with synthetic ice modulators in presence and absence of biological tissues.

    Science.gov (United States)

    Eisenberg, David P; Taylor, Michael J; Rabin, Yoed

    2012-10-01

    This study explores physical effects associated with the application of cryopreservation via vitrification using a class of compounds which are defined here as synthetic ice modulators (SIMs). The general classification of SIMs includes molecules that modulate ice nucleation and growth, or possess properties of stabilizing the amorphous state, by virtue of their chemical structure and at concentrations that are not explained on a purely colligative basis. A sub-category of SIMs, referred to in the literature as synthetic ice blockers (SIBs), are compounds that interact directly with ice nuclei or crystals to modify their structure and/or rate of growth. The current study is part of an ongoing effort to characterize thermo-mechanical effects during vitrification, with emphasis on measuring the physical property of thermal expansion-the driving mechanism to thermo-mechanical stress. Materials under investigation are the cryoprotective agent (CPA) cocktail DP6 in combination with one of the following SIMs: 12% polyethylene glycol 400, 6% 1,3 cyclohexanediol, and 6% 2,3 butanediol. Results are presented for the CPA-SIM cocktail in the absence and presence of bovine muscle and goat artery specimens. This study focuses on the upper part of the cryogenic temperature range, where the CPA behaves as a fluid for all practical applications. Results of this study indicate that the addition of SIMs to DP6 allows lower cooling rates to ensure vitrification and extends the range of measurements. It is demonstrated that the combination of SIM with DP6 increases the thermal expansion of the cocktail, with implications for the likelihood of fracture formation-the most dramatic outcome of thermo-mechanical stress. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Induction, purification and characterization of a novel manganese peroxidase from Irpex lacteus CD2 and its application in the decolorization of different types of dye.

    Directory of Open Access Journals (Sweden)

    Xing Qin

    Full Text Available Manganese peroxidase (MnP is the one of the important ligninolytic enzymes produced by lignin-degrading fungi which has the great application value in the field of environmental biotechnology. Searching for new MnP with stronger tolerance to metal ions and organic solvents is important for the maximization of potential of MnP in the biodegradation of recalcitrant xenobiotics. In this study, it was found that oxalic acid, veratryl alcohol and 2,6-Dimehoxyphenol could stimulate the synthesis of MnP in the white-rot fungus Irpex lacteus CD2. A novel manganese peroxidase named as CD2-MnP was purified and characterized from this fungus. CD2-MnP had a strong capability for tolerating different metal ions such as Ca2+, Cd2+, Co2+, Mg2+, Ni2+ and Zn2+ as well as organic solvents such as methanol, ethanol, DMSO, ethylene glycol, isopropyl alcohol, butanediol and glycerin. The different types of dyes including the azo dye (Remazol Brilliant Violet 5R, Direct Red 5B, anthraquinone dye (Remazol Brilliant Blue R, indigo dye (Indigo Carmine and triphenylmethane dye (Methyl Green as well as simulated textile wastewater could be efficiently decolorized by CD2-MnP. CD2-MnP also had a strong ability of decolorizing different dyes with the coexistence of metal ions and organic solvents. In summary, CD2-MnP from Irpex lacteus CD2 could effectively degrade a broad range of synthetic dyes and exhibit a great potential for environmental biotechnology.

  12. Metabolic characterization of Palatinate German white wines according to sensory attributes, varieties, and vintages using NMR spectroscopy and multivariate data analyses

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Kashif; Maltese, Federica [Leiden University, Division of Pharmacognosy, Section Metabolomics, Institute of Biology (Netherlands); Toepfer, Reinhard [Institute for Grapevine Breeding Geilweilerhof, Julius Kuehn Institute (JKI), Federal Research Centre for Cultivated Plants (Germany); Choi, Young Hae, E-mail: y.choi@chem.leidenuniv.nl; Verpoorte, Robert [Leiden University, Division of Pharmacognosy, Section Metabolomics, Institute of Biology (Netherlands)

    2011-04-15

    {sup 1}H NMR (nuclear magnetic resonance spectroscopy) has been used for metabolomic analysis of 'Riesling' and 'Mueller-Thurgau' white wines from the German Palatinate region. Diverse two-dimensional NMR techniques have been applied for the identification of metabolites, including phenolics. It is shown that sensory analysis correlates with NMR-based metabolic profiles of wine. {sup 1}H NMR data in combination with multivariate data analysis methods, like principal component analysis (PCA), partial least squares projections to latent structures (PLS), and bidirectional orthogonal projections to latent structures (O2PLS) analysis, were employed in an attempt to identify the metabolites responsible for the taste of wine, using a non-targeted approach. The high quality wines were characterized by elevated levels of compounds like proline, 2,3-butanediol, malate, quercetin, and catechin. Characterization of wine based on type and vintage was also done using orthogonal projections to latent structures (OPLS) analysis. 'Riesling' wines were characterized by higher levels of catechin, caftarate, valine, proline, malate, and citrate whereas compounds like quercetin, resveratrol, gallate, leucine, threonine, succinate, and lactate, were found discriminating for 'Mueller-Thurgau'. The wines from 2006 vintage were dominated by leucine, phenylalanine, citrate, malate, and phenolics, while valine, proline, alanine, and succinate were predominantly present in the 2007 vintage. Based on these results, it can be postulated the NMR-based metabolomics offers an easy and comprehensive analysis of wine and in combination with multivariate data analyses can be used to investigate the source of the wines and to predict certain sensory aspects of wine.

  13. Comparative study of a new dermal filler Uma Jeunesse® and Juvéderm®.

    Science.gov (United States)

    Sharma, Peeyush; Sharma, Siroj

    2011-06-01

    Innovation in technology has resulted in the emergence of better, longer-lasting hyaluronic acid implants with fewer side effects. The new dermal implant Uma Jeunesse® was compared to Juvéderm® in this split-face study. Uma Jeunesse® is crosslinked with butanediol diglycidyl ether (BDDE) using a new crosslinking technology. Uma Jeunesse® and Juvéderm® Ultra 3 were injected in a split-face study on 17 healthy volunteers, whose ages ranged from 33-58 years. There were 14 women and three men with medium to deep nasolabial folds. All subjects randomly received either Uma Jeunesse® or Juvéderm®) Ultra 3 on one half of their face. Patients were followed up for 9 months. Juvéderm® was easier to inject with lesser injection pain because of lidocaine, but late postinjection pain was much less with Uma Jeunesse® as compared to Juvéderm®. Overall rate of early and late complications as well as adverse events was lower with Uma Jeunesse® than Juvéderm(®) . After 9 months of follow-up, Uma Jeunesse® lasted in tissues for longer as compared to Juvéderm(®) even in patients injected for the first time (PJeunesse® was also much higher. Perception of pain during injection was lesser with Juvéderm® probably because of the presence of lidocaine. The new dermal implant Uma Jeunesse® is a safe and patient-friendly product which resides in the tissues for longer with maintenance of aesthetic effect over and beyond 6 months, reaching 9 months in over 80% of patients, and Juvéderm® injection is less painful. © 2011 Wiley Periodicals, Inc.

  14. Effect of replacing polyol by organosolv and kraft lignin on the property and structure of rigid polyurethane foam

    Science.gov (United States)

    2013-01-01

    Background Lignin is one of the three major components in plant cell walls, and it can be isolated (dissolved) from the cell wall in pretreatment or chemical pulping. However, there is a lack of high-value applications for lignin, and the commonest proposal for lignin is power and steam generation through combustion. Organosolv ethanol process is one of the effective pretreatment methods for woody biomass for cellulosic ethanol production, and kraft process is a dominant chemical pulping method in paper industry. In the present research, the lignins from organosolv pretreatment and kraft pulping were evaluated to replace polyol for producing rigid polyurethane foams (RPFs). Results Petroleum-based polyol was replaced with hardwood ethanol organosolv lignin (HEL) or hardwood kraft lignin (HKL) from 25% to 70% (molar percentage) in preparing rigid polyurethane foam. The prepared foams contained 12-36% (w/w) HEL or 9-28% (w/w) HKL. The density, compressive strength, and cellular structure of the prepared foams were investigated and compared. Chain extenders were used to improve the properties of the RPFs. Conclusions It was found that lignin was chemically crosslinked not just physically trapped in the rigid polyurethane foams. The lignin-containing foams had comparable structure and strength up to 25-30% (w/w) HEL or 19-23% (w/w) HKL addition. The results indicated that HEL performed much better in RPFs and could replace more polyol at the same strength than HKL because the former had a better miscibility with the polyol than the latter. Chain extender such as butanediol could improve the strength of lignin-containing RPFs. PMID:23356502

  15. Anion exchangers with branched functional ion exchange layers of different hydrophilicity for ion chromatography.

    Science.gov (United States)

    Shchukina, O I; Zatirakha, A V; Smolenkov, A D; Nesterenko, P N; Shpigun, O A

    2015-08-21

    Novel polystyrene-divinylbenzene (PS-DVB) based anion exchangers differing from each other in the structure of the branched functional ion exchange layer are prepared to investigate the role of linker and functional site on ion exchange selectivity. The proposed method of synthesis includes the obtaining of aminated PS-DVB particles by means of their acylation with following reductive amination with methylamine. Further modification of the obtained secondary aminogroups is provided by the alkylation with either 1,4-butanediol diglycidyl ether (1,4-BDDGE) or resorcinol diglycidyl ether (RDGE), which form the linkers of different hydrophobicity, and amination of terminal epoxide rings with trimethylamine (TMA), dimethylethanolamine (DMEA), methyldiethanolamine (MDEA) or triethanolamine (TEA). The variation of the structure and hydrophobicity of the linker and terminal quaternary ammonium sites in the functional layer allows the alteration of selectivity and separation efficiency of the obtained adsorbents. The ion exchange selectivity and separation efficiency of the anion exchangers are evaluated using the model mixtures of anions (F(-), HCOO(-), Cl(-), NO2(-), Br(-), NO3(-), HPO4(2-) and SO4(2-)) in potassium hydroxide eluents. The adsorbents show the decrease of selectivity with increasing the hydrophilicity of the terminal functional site. The anion exchangers having more flexible and hydrophilic 1,4-BDDGE linker provide smaller separation factors for most of the analytes as compared with RDGE-containing adsorbents with the same terminal ion exchange sites, but are characterized with higher column efficiencies and better peak symmetry for polarizable anions. In case of 1,4-BDDGE-modified anion exchangers of the particle size of 3.3μm functionalized with DMEA and MDEA the calculated values of column efficiencies for polarizable NO3(-) and Br(-) are up to 49,000 and 53,000N/m, respectively, which is almost twice higher than the values obtained for the RDGE

  16. Acinetobactercelticus sp. nov., a psychrotolerant species widespread in natural soil and water ecosystems.

    Science.gov (United States)

    Radolfova-Krizova, Lenka; Maixnerova, Martina; Nemec, Alexandr

    2016-12-01

    A novel, taxonomically unique group of six strains of the genus Acinetobacter was discovered during an exploratory study on strains culturable from soil and water natural ecosystems in the Bohemian part of the Czech Republic. Based on the comparative analyses of the 16S rRNA gene, gyrB and rpoB sequences, these strains formed strongly supported and internally coherent clusters (intracluster identities of ≥99.9, ≥96.1 and ≥97.3 %, respectively), which were clearly separated from all known species of the genus Acinetobacter (≤98.7, ≤83.2 and ≤88.9 %, respectively). The distinctness of the group at the species level was evidenced also by the results of the genus-wide analyses of the whole-cell mass fingerprints of the six strains generated by matrix-assisted laser desorption/ionization-time-of-flight MS and the whole-genome sequence of a group member, ANC 4603T. Compared with the known species of the genus Acinetobacter, all six strains exhibited a unique phenotype, characterized by psychrotolerance (growth at 1 °C through 28 °C), the inability to grow at 32 °C and the ability to assimilate l-aspartate and malonate but not 2,3-butanediol or citrate. Based on these results, the name Acinetobacter celticus sp. nov. is proposed for the taxon represented by the six strains. The type strain is ANC 4603T (=CCM 8700T=CCUG 69239T=CNCTC 7549T).

  17. Novel Psychoactive Substances—Recent Progress on Neuropharmacological Mechanisms of Action for Selected Drugs

    Science.gov (United States)

    Hassan, Zurina; Bosch, Oliver G.; Singh, Darshan; Narayanan, Suresh; Kasinather, B. Vicknasingam; Seifritz, Erich; Kornhuber, Johannes; Quednow, Boris B.; Müller, Christian P.

    2017-01-01

    A feature of human culture is that we can learn to consume chemical compounds, derived from natural plants or synthetic fabrication, for their psychoactive effects. These drugs change the mental state and/or the behavioral performance of an individual and can be instrumentalized for various purposes. After the emergence of a novel psychoactive substance (NPS) and a period of experimental consumption, personal and medical benefits and harm potential of the NPS can be estimated on evidence base. This may lead to a legal classification of the NPS, which may range from limited medical use, controlled availability up to a complete ban of the drug form publically accepted use. With these measures, however, a drug does not disappear, but frequently continues to be used, which eventually allows an even better estimate of the drug’s properties. Thus, only in rare cases, there is a final verdict that is no more questioned. Instead, the view on a drug can change from tolerable to harmful but may also involve the new establishment of a desired medical application to a previously harmful drug. Here, we provide a summary review on a number of NPS for which the neuropharmacological evaluation has made important progress in recent years. They include mitragynine (“Kratom”), synthetic cannabinoids (e.g., “Spice”), dimethyltryptamine and novel serotonergic hallucinogens, the cathinones mephedrone and methylone, ketamine and novel dissociative drugs, γ-hydroxybutyrate, γ-butyrolactone, and 1,4-butanediol. This review shows not only emerging harm potentials but also some potential medical applications. PMID:28868040

  18. Novel Psychoactive Substances—Recent Progress on Neuropharmacological Mechanisms of Action for Selected Drugs

    Directory of Open Access Journals (Sweden)

    Zurina Hassan

    2017-08-01

    Full Text Available A feature of human culture is that we can learn to consume chemical compounds, derived from natural plants or synthetic fabrication, for their psychoactive effects. These drugs change the mental state and/or the behavioral performance of an individual and can be instrumentalized for various purposes. After the emergence of a novel psychoactive substance (NPS and a period of experimental consumption, personal and medical benefits and harm potential of the NPS can be estimated on evidence base. This may lead to a legal classification of the NPS, which may range from limited medical use, controlled availability up to a complete ban of the drug form publically accepted use. With these measures, however, a drug does not disappear, but frequently continues to be used, which eventually allows an even better estimate of the drug’s properties. Thus, only in rare cases, there is a final verdict that is no more questioned. Instead, the view on a drug can change from tolerable to harmful but may also involve the new establishment of a desired medical application to a previously harmful drug. Here, we provide a summary review on a number of NPS for which the neuropharmacological evaluation has made important progress in recent years. They include mitragynine (“Kratom”, synthetic cannabinoids (e.g., “Spice”, dimethyltryptamine and novel serotonergic hallucinogens, the cathinones mephedrone and methylone, ketamine and novel dissociative drugs, γ-hydroxybutyrate, γ-butyrolactone, and 1,4-butanediol. This review shows not only emerging harm potentials but also some potential medical applications.

  19. Correlação entre propriedades mecânicas e parâmetros estruturais de poliuretanos à base de poli(épsilon-caprolactona Relationships between mechanical properties and structural parameters of polyurethanes containing poly(epsilon-caprolactone

    Directory of Open Access Journals (Sweden)

    Juliana Kloss

    2005-03-01

    Full Text Available No presente trabalho foram preparados poliuretanos (PUs segmentados. Primeiramente foi obtido um pré-polímero (PP a partir da reação de 2,4 e 2,6 - diisocianato de tolileno (TDI e poli(épsilon-caprolactona diol (PCL. A PCL é um poliéster biodegradável que constituiu o segmento flexível do PU. O segmento rígido foi constituído por unidades uretânicas provenientes da ligação entre as extremidades isocianato do PP e as hidroxilas do extensor de cadeia: 1,4 - butanodiol (BDO, ou sacarose (SAC, ou glicose (GLY. Foram avaliadas as propriedades mecânicas e dinâmico-mecânicas dos poliuretanos obtidos e estas foram correlacionadas com os parâmetros estruturais. Os resultados foram justificados com base na intensidade das interações de hidrogênio, na mistura de fases, no volume dos extensores cíclicos e na presença de ligações cruzadas. Estes PUs estão sendo estudados com vistas à preparação de materiais biodegradáveis com propriedades mecânicas úteis.Segmented polyurethanes containing polycaprolactone as soft segment were prepared taking into account the biodegradable character of this compound. The hard block was produced by the reaction between tolylene diisocyanate and a chain extender (1,4 butanediol, sucrose or glucose. The mechanical and dynamical properties were evaluated as a function of the contents of rigid blocks. The results were analyzed on the basis of the intermolecular interactions, mainly H bonds, phase mixture, volume of cyclic chain extenders and crosslinking. These polyurethanes are being studied aiming at the preparation of biodegradable materials with useful mechanical properties.

  20. Cloning, functional expression and characterization of a bifunctional 3-hydroxybutanal dehydrogenase /reductase involved in acetone metabolism by Desulfococcus biacutus.

    Science.gov (United States)

    Frey, Jasmin; Rusche, Hendrik; Schink, Bernhard; Schleheck, David

    2016-11-25

    The strictly anaerobic, sulfate-reducing bacterium Desulfococcus biacutus can utilize acetone as sole carbon and energy source for growth. Whereas in aerobic and nitrate-reducing bacteria acetone is activated by carboxylation with CO 2 to acetoacetate, D. biacutus involves CO as a cosubstrate for acetone activation through a different, so far unknown pathway. Proteomic studies indicated that, among others, a predicted medium-chain dehydrogenase/reductase (MDR) superfamily, zinc-dependent alcohol dehydrogenase (locus tag DebiaDRAFT_04514) is specifically and highly produced during growth with acetone. The MDR gene DebiaDRAFT_04514 was cloned and overexpressed in E. coli. The purified recombinant protein required zinc as cofactor, and accepted NADH/NAD + but not NADPH/NADP + as electron donor/acceptor. The pH optimum was at pH 8, and the temperature optimum at 45 °C. Highest specific activities were observed for reduction of C 3 - C 5 -aldehydes with NADH, such as propanal to propanol (380 ± 15 mU mg -1 protein), butanal to butanol (300 ± 24 mU mg -1 ), and 3-hydroxybutanal to 1,3-butanediol (248 ± 60 mU mg -1 ), however, the enzyme also oxidized 3-hydroxybutanal with NAD + to acetoacetaldehyde (83 ± 18 mU mg -1 ). The enzyme might play a key role in acetone degradation by D. biacutus, for example as a bifunctional 3-hydroxybutanal dehydrogenase/reductase. Its recombinant production may represent an important step in the elucidation of the complete degradation pathway.

  1. Effects of Ensiling Fermentation and Aerobic Deterioration on the Bacterial Community in Italian Ryegrass, Guinea Grass, and Whole-crop Maize Silages Stored at High Moisture Content

    Science.gov (United States)

    Li, Yanbing; Nishino, Naoki

    2013-01-01

    The effects of storage period and aerobic deterioration on the bacterial community were examined in Italian ryegrass (IR), guinea grass (GG), and whole-crop maize (WM) silages. Direct-cut forages were stored in a laboratory silo for 3, 7, 14, 28, 56, and 120 d without any additives; live counts, content of fermentation products, and characteristics of the bacterial community were determined. 2,3-Butanediol, acetic acid, and lactic acid were the dominant fermentation products in the IR, GG, and WM silages, respectively. The acetic acid content increased as a result of prolonged ensiling, regardless of the type of silage crop, and the changes were distinctively visible from the beginning of GG ensiling. Pantoea agglomerans, Rahnella aquatilis, and Enterobacter sp. were the major bacteria in the IR silage, indicating that alcoholic fermentation may be due to the activity of enterobacteria. Staphylococcus sciuri and Bacillus pumilus were detected when IR silage was spoiled, whereas between aerobically stable and unstable silages, no differences were seen in the bacterial community at silo opening. Lactococcus lactis was a representative bacterium, although acetic acid was the major fermentation product in the GG silage. Lactobacillus plantarum, Lactobacillus brevis, and Morganella morganii were suggested to be associated with the increase in acetic acid due to prolonged storage. Enterobacter cloacae appeared when the GG silage was spoiled. In the WM silage, no distinctive changes due to prolonged ensiling were seen in the bacterial community. Throughout the ensiling, Weissella paramesenteroides, Weissella confusa, and Klebsiella pneumoniae were present in addition to L. plantarum, L. brevis, and L. lactis. Upon deterioration, Acetobacter pasteurianus, Klebsiella variicola, Enterobacter hormaechei, and Bacillus gibsonii were detected. These results demonstrate the diverse bacterial community that evolves during ensiling and aerobic spoilage of IR, GG, and WM silages

  2. Mono-fermentation of glycerine - Fermentation of a substrate in a dominant amount. Final report; Monovergaerung von Glycerin - Vergaerung von einem Substrat in dominierender Menge. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Erb, D.; Bueeler, E.; Spicher, M.

    2008-02-15

    The present study investigated the feasibility of a mono fermentation of the glycerine-fraction from biodiesel production. Part of the experiments took place in a single-stage, continuous system with 700 l usable volume. The maximum yield of biogas of the glycerine-fraction is 1100 l/l of glycerine, or 870 l/kg of glycerine, in continuous operation. The average methane content is 70 %. The adaptation rate of the biomass at the substrate of glycerine-fraction is high. Two or three days after starting the feed 100 % degradation rates will be achieved. The single-stage, continuous fermentation of the glycerine-fraction at 40 {sup o}C runs only stable at very low organic loading rate (0.65 kg oDM/(d m{sup 3})) and is therefore not currently economical. At higher organic loading rates (1.5 to 3.0 kg oDM/(d m{sup 3})) the adapted biomass collapsed after about 20 days due to massive instability of the process. A two-stage system with separate hydrolysis stage could probably allow a stable fermentation as search for literature has shown. Fed-batch experiments in the laboratory of the University of Waedenswil, Switzerland (ZHAW) demonstrated that the glycerine-fraction from biodiesel production is slightly better degradable than pure glycerine. The process dysfunctions arise because of the inhibition of intermediates resulting from the degradation of glycerine. At higher concentrations of 1.2-propanediol and 2.3-butanediol the degradation was incomplete. Further inhibitors can not be excluded. The failed stability of the process is not due to the lack of main nutrients or trace elements. (author)

  3. Synthesis and characterization of cycloaliphatic hydrophilic polyurethanes, modified with l-ascorbic acid, as materials for soft tissue regeneration.

    Science.gov (United States)

    Kucinska-Lipka, J; Gubanska, I; Strankowski, M; Cieśliński, H; Filipowicz, N; Janik, H

    2017-06-01

    In this paper we described synthesis and characteristic of obtained hydrophilic polyurethanes (PURs) modified with ascorbic acid (commonly known as vitamin C). Such materials may find an application in the biomedical field, for example in the regenerative medicine of soft tissues, according to ascorbic acid wide influence on tissue regeneration Flora (2009), Szymańska-Pasternak et al. (2011), Taikarimi and Ibrahim (2011), Myrvik and Volk (1954), Li et al. (2001), Cursino et al. (2005) . Hydrophilic PURs were obtained with the use of amorphous α,ω-dihydroxy(ethylene-butylene adipate) (dHEBA) polyol, 1,4-butanediol (BDO) chain extender and aliphatic 4,4'-methylenebis(cyclohexyl isocyanate) (HMDI). HMDI was chosen as a nontoxic diisocyanate, suitable for biomedical PUR synthesis. Modification with l-ascorbic acid (AA) was performed to improve obtained PUR materials biocompatibility. Chemical structure of obtained PURs was provided and confirmed by Fourier transform infrared spectroscopy (FTIR) and Proton nuclear magnetic resonance spectroscopy ( 1 HNMR). Differential scanning calorimetry (DSC) was used to indicate the influence of ascorbic acid modification on such parameters as glass transition temperature, melting temperature and melting enthalpies of obtained materials. To determine how these materials may potentially behave, after implementation in tissue, degradation behavior of obtained PURs in various chemical environments, which were represented by canola oil, saline solution, distilled water and phosphate buffered saline (PBS) was estimated. The influence of AA on hydrophilic-hydrophobic character of obtained PURs was established by contact angle study. This experiment revealed that ascorbic acid significantly improves hydrophilicity of obtained PUR materials and the same cause that they are more suitable candidates for biomedical applications. Good hemocompatibility characteristic of studied PUR materials was confirmed by the hemocompatibility test with

  4. Biosynthesis and characterization of diblock copolymer of p(3-hydroxypropionate)-block-p(4-hydroxybutyrate) from recombinant Escherichia coli.

    Science.gov (United States)

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

    2013-03-11

    Poly(4-hydroxybutyrate) (P4HB) is a highly elastic polymer, whereas poly(3-hydroxypropionate) (P3HP) is a polymer with enormous tensile strength. This study aimed to biosynthesize a block copolymer consisting of soft P4HB block with a strong P3HP block to gain unique and excellent material properties. A recombinant Escherichia coli strain that produces homopolymers of P3HP and P4HB was employed for the block copolymer synthesis. When the strain was grown in the presence of 1,4-butanediol (BDO) as a 4HB precursor, P4HB block was formed. Sequential supplementation of 1,3-propanediol (PDO) as a 3HP precursor allowed the strain to produce P3HP block. Thermal, NMR, fractionation, and mechanical characterizations confirmed the resulting polymer as a block copolymer of P3HP-b-P4HB. Two block copolymers were formed from this study, including the P3HP-b-29% P4HB and P3HP-b-37% P4HB, they showed superior properties over random copolymers P(3HP-co-4HB). The block copolymers had two glass transition temperatures (Tg) and two melting temperatures (Tm). In comparison to the homopolymers P3HP and P4HB, incorporation of block microstructure resulted in the lowering of Tm, block copolymers were revealed with higher Young's modulus, yield strengths, and tension strengths much better than the previously reported random copolymers of similar compositions. Block copolymerization of P3HP and P4HB adds a new vision on PHA polymerization by generation of new polymers with superior properties.

  5. In silico metabolic engineering of Clostridium ljungdahlii for synthesis gas fermentation.

    Science.gov (United States)

    Chen, Jin; Henson, Michael A

    2016-11-01

    Synthesis gas fermentation is one of the most promising routes to convert synthesis gas (syngas; mainly comprised of H2 and CO) to renewable liquid fuels and chemicals by specialized bacteria. The most commonly studied syngas fermenting bacterium is Clostridium ljungdahlii, which produces acetate and ethanol as its primary metabolic byproducts. Engineering of C. ljungdahlii metabolism to overproduce ethanol, enhance the synthesize of the native byproducts lactate and 2,3-butanediol, and introduce the synthesis of non-native products such as butanol and butyrate has substantial commercial value. We performed in silico metabolic engineering studies using a genome-scale reconstruction of C. ljungdahlii metabolism and the OptKnock computational framework to identify gene knockouts that were predicted to enhance the synthesis of these native products and non-native products, introduced through insertion of the necessary heterologous pathways. The OptKnock derived strategies were often difficult to assess because increase product synthesis was invariably accompanied by decreased growth. Therefore, the OptKnock strategies were further evaluated using a spatiotemporal metabolic model of a syngas bubble column reactor, a popular technology for large-scale gas fermentation. Unlike flux balance analysis, the bubble column model accounted for the complex tradeoffs between increased product synthesis and reduced growth rates of engineered mutants within the spatially varying column environment. The two-stage methodology for deriving and evaluating metabolic engineering strategies was shown to yield new C. ljungdahlii gene targets that offer the potential for increased product synthesis under realistic syngas fermentation conditions. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  6. Development of porous polyurethane/strontium-substituted hydroxyapatite composites for bone regeneration.

    Science.gov (United States)

    Sariibrahimoglu, Kemal; Yang, Wanxun; Leeuwenburgh, Sander C G; Yang, Fang; Wolke, Joop G C; Zuo, Yi; Li, Yubao; Jansen, John A

    2015-06-01

    Polyurethane (PU) has been widely used for the biomedical applications but its potential for bone regeneration is limited due to its lack of osteoconductive properties. Strontium substituted hydroxyapatite (SrHA) particles, on the other hand, are known to exhibit a positive effect on bone formation. Therefore, the aim of this study was to (i) develop porous polyurethane scaffolds containing strontium SrHA nanoparticles (PU/SrHA) and (ii) compare their in vitro biological performance for applications in bone regeneration to PU scaffolds. SrHA and HA was synthesized using a conventional wet-chemical neutralization reaction at temperatures of 25, 50, and 80°C. Chemical analysis was performed by inductively coupled plasma-optical emission spectrometry. Synthesizing temperatures at 25 and at 50°C were selected for the composite preparation (abbreviated as HA-25, SrHA-25, HA-50, and SrHA-50, respectively). PU was synthesized from isophorone diisocyanate, polytetramethylene ether glycol, and 1,4-butanediol. Composite scaffolds were prepared by addition of HA or SrHA nanoparticles into PU scaffolds during polymer preparation. The results showed that the Sr content in HA nanoparticles increased with increasing synthesis temperature. The addition of nanoparticles decreased the elongation-at-break and tensile strength, but significantly increased the surface wettability of the PU scaffolds. In vitro degradation tests demonstrated that release of cations was significantly higher from PU/SrHA-50 composite scaffolds. Cell culture tests indicated that PU composites containing either HA or SrHA nanoparticles increased proliferation of bone marrow stem cells as compared to plain PU scaffolds, whereas osteogenic differentiation was not affected by the incorporation of HA nanoparticles irrespective of the incorporation of Sr. © 2014 Wiley Periodicals, Inc.

  7. Transcriptional responses to sucrose mimic the plant-associated life style of the plant growth promoting endophyte Enterobacter sp. 638.

    Directory of Open Access Journals (Sweden)

    Safiyh Taghavi

    Full Text Available Growth in sucrose medium was previously found to trigger the expression of functions involved in the plant associated life style of the endophytic bacterium Enterobacter sp. 638. Therefore, comparative transcriptome analysis between cultures grown in sucrose or lactate medium was used to gain insights in the expression levels of bacterial functions involved in the endophytic life style of strain 638. Growth on sucrose as a carbon source resulted in major changes in cell physiology, including a shift from a planktonic life style to the formation of bacterial aggregates. This shift was accompanied by a decrease in transcription of genes involved in motility (e.g., flagella biosynthesis and an increase in the transcription of genes involved in colonization, adhesion and biofilm formation. The transcription levels of functions previously suggested as being involved in endophytic behavior and functions responsible for plant growth promoting properties, including the synthesis of indole-acetic acid, acetoin and 2,3-butanediol, also increased significantly for cultures grown in sucrose medium. Interestingly, despite an abundance of essential nutrients transcription levels of functions related to uptake and processing of nitrogen and iron became increased for cultures grown on sucrose as sole carbon source. Transcriptome data were also used to analyze putative regulatory relationships. In addition to the small RNA csrABCD regulon, which seems to play a role in the physiological adaptation and possibly the shift between free-living and plant-associated endophytic life style of Enterobacter sp. 638, our results also pointed to the involvement of rcsAB in controlling responses by Enterobacter sp. 638 to a plant-associated life style. Targeted mutagenesis was used to confirm this role and showed that compared to wild-type Enterobacter sp. 638 a ΔrcsB mutant was affected in its plant growth promoting ability.

  8. Ketone Diester Ingestion Impairs Time-Trial Performance in Professional Cyclists

    Directory of Open Access Journals (Sweden)

    Jill J. Leckey

    2017-10-01

    Full Text Available We investigated the effect of pre- “race” ingestion of a 1,3-butanediol acetoacetate diester on blood ketone concentration, substrate metabolism and performance of a cycling time trial (TT in professional cyclists. In a randomized cross-over design, 10 elite male cyclists completed a ~31 km laboratory-based TT on a cycling ergometer programmed to simulate the 2017 World Road Cycling Championships course. Cyclists consumed a standardized meal [2 g/kg body mass (BM carbohydrate (CHO] the evening prior to a trial day and a CHO breakfast (2 g/kg BM CHO with 200 mg caffeine on the morning of a trial day. Cyclists were randomized to consume either the ketone diester (2 × 250 mg/kg or a placebo drink, followed immediately by 200 mL diet cola, given ~ 30 min before and immediately prior to commencing a 20 min incremental warm-up. Blood samples were collected prior to and during the warm-up, pre- and post- TT and at regular intervals after the TT. Urine samples were collected pre- and post- warm-up, immediately post TT and 60 min post TT. Pre-exercise ingestion of the diester resulted in a 2 ± 1% impairment in TT performance that was associated with gut discomfort and higher perception of effort. Serum β-hydroxybutyrate, serum acetoacetate, and urine ketone concentrations increased from rest following ketone ingestion and were higher than placebo throughout the trial. Ketone ingestion induces hyperketonemia in elite professional cyclists when in a carbohydrate fed state, and impairs performance of a cycling TT lasting ~50 min.

  9. Induction, Purification and Characterization of a Novel Manganese Peroxidase from Irpex lacteus CD2 and Its Application in the Decolorization of Different Types of Dye

    Science.gov (United States)

    Qin, Xing; Zhang, Jie; Zhang, Xiaoyu; Yang, Yang

    2014-01-01

    Manganese peroxidase (MnP) is the one of the important ligninolytic enzymes produced by lignin-degrading fungi which has the great application value in the field of environmental biotechnology. Searching for new MnP with stronger tolerance to metal ions and organic solvents is important for the maximization of potential of MnP in the biodegradation of recalcitrant xenobiotics. In this study, it was found that oxalic acid, veratryl alcohol and 2,6-Dimehoxyphenol could stimulate the synthesis of MnP in the white-rot fungus Irpex lacteus CD2. A novel manganese peroxidase named as CD2-MnP was purified and characterized from this fungus. CD2-MnP had a strong capability for tolerating different metal ions such as Ca2+, Cd2+, Co2+, Mg2+, Ni2+ and Zn2+ as well as organic solvents such as methanol, ethanol, DMSO, ethylene glycol, isopropyl alcohol, butanediol and glycerin. The different types of dyes including the azo dye (Remazol Brilliant Violet 5R, Direct Red 5B), anthraquinone dye (Remazol Brilliant Blue R), indigo dye (Indigo Carmine) and triphenylmethane dye (Methyl Green) as well as simulated textile wastewater could be efficiently decolorized by CD2-MnP. CD2-MnP also had a strong ability of decolorizing different dyes with the coexistence of metal ions and organic solvents. In summary, CD2-MnP from Irpex lacteus CD2 could effectively degrade a broad range of synthetic dyes and exhibit a great potential for environmental biotechnology. PMID:25412169

  10. Synthesis of thermoplastic poly(ester-olefin elastomers

    Directory of Open Access Journals (Sweden)

    Tanasijević Branka

    2004-01-01

    Full Text Available A series of thermoplastic poly(ester-olefin elastomers, based on poly(ethylene-stat-butylene, HO-PEB-OH, as the soft segment and poly (butylene terephthalate, PBT, as the hard segment, were synthesized by a catalyzed transesterification reaction in solution. The incorporation of soft hydrogenated poly(butadiene segments into the copolyester backbone was accomplished by the polycondensation of α, ω-dihydroxyl telechelic HO-PEB-OH, (PEB Mn = 3092 g/mol with 1,4-butanediol (BD and dimethyl terephthalate (DMT in the presence of a 50 wt-% high boiling solvent i.e., 1,2,4-trichlorobenzene. The molar ratio of the starting comonomers was selected to result in a constant hard to soft weight ratio of 60:40. The synthesis was optimized in terms of both the concentration of catalyst, tetra-n-butyl-titanate (Ti(OBu4, and stabilizer, N,N'-diphenyl-p-phenylenediamine (DPPD, as well as the reaction time. It was found that the optimal catalyst concentration (Ti(OBu4 for the synthesis of these thermoplastic elastomers was 1.0 mmol/mol ester and the optimal DPPD concentration was 1.0 wt-%. The extent of the reaction was followed by measuring the inherent viscosity of the reaction mixture. The effectiveness of the incorporation of the soft segments into the copolymer chains was proved by Soxhlet extraction with chloroform. The molecular structures, composition and the size of the synthesized poly(ester-butylenes were verified by 1H NMR spectroscopy, viscometry of dilute solutions and the complex dynamic melt viscosity. The thermal properties of poly(ester-olefins were investigated by differential scanning calorimetry (DSC. The degree of crystallinity was also determined by DSC. The thermal and thermo-oxidative stability were investigated by thermogravimetric analysis (TGA. The rheological properties of poly(ester-olefins were investigated by dynamic mechanical spectroscopy in the melt and solid state.

  11. Influence of the content of hard segments on the properties of novel urethane-siloxane copolymers based on a poly(ε-caprolactone-b-poly(dimethylsiloxane-b-poly(ε- caprolactone triblock copolymer

    Directory of Open Access Journals (Sweden)

    Antić Vesna V.

    2011-01-01

    Full Text Available A series of novel thermoplastic urethane-siloxane copolymers (TPUSs based on a α,ω-dihydroxy-[poly(ε-caprolactone-bpoly( dimethylsiloxane-b-poly(ε-caprolactone] (α,ω-dihydroxy-PCLPDMS- PCL triblock copolymer, 4,4?-methylenediphenyl diisocyanate (MDI and 1,4-butanediol (BD was synthesized. The effects of the content (9-63 wt. % of hard urethane segments and their degree of polymerization on the properties of the segmented TPUSs were investigated. The structure, composition and hard segment degree of polymerization of the hard segments were examined using 1H- and quantitative 13C-NMR spectroscopy. The degree of crystallinity of the synthesized copolymers was determined using wide-angle X-ray scattering (WAXS. The surface properties were evaluated by measuring the water contact angle and water absorption. In the series of the TPUSs, the average degree of polymerization of the hard segments was varied from 1.2 to 14.4 MDI-BD units. It was found that average values from 3.8 to 14.4 MDI-BD units were effective segment lengths for crystallization of hard segments, which resulted in an increase in the degree of microphase separation of the copolymers. Spherulite-like superstructures were observed in copolymer films by scanning electron microscopy (SEM, which are believed to arise from the crystallization of the hard segments and/or PCL segments, depending on the content of the hard segments. The surface of the copolymers became more hydrophobic with increasing weight fraction of PDMS. The synthesized copolymers based on a PCL-PDMS-PCL segment showed good thermal stability, which increased with increasing content of soft PDMS segments, as was confirmed by the value of the starting temperature of thermal degradation.

  12. Insights into CO2 Fixation Pathway of Clostridium autoethanogenum by Targeted Mutagenesis

    Directory of Open Access Journals (Sweden)

    Fungmin Liew

    2016-05-01

    Full Text Available The future sustainable production of chemicals and fuels from nonpetrochemical resources and reduction of greenhouse gas emissions are two of the greatest societal challenges. Gas fermentation, which utilizes the ability of acetogenic bacteria such as Clostridium autoethanogenum to grow and convert CO2 and CO into low-carbon fuels and chemicals, could potentially provide solutions to both. Acetogens fix these single-carbon gases via the Wood-Ljungdahl pathway. Two enzyme activities are predicted to be essential to the pathway: carbon monoxide dehydrogenase (CODH, which catalyzes the reversible oxidation of CO to CO2, and acetyl coenzyme A (acetyl-CoA synthase (ACS, which combines with CODH to form a CODH/ACS complex for acetyl-CoA fixation. Despite their pivotal role in carbon fixation, their functions have not been confirmed in vivo. By genetically manipulating all three CODH isogenes (acsA, cooS1, and cooS2 of C. autoethanogenum, we highlighted the functional redundancies of CODH by demonstrating that cooS1 and cooS2 are dispensable for autotrophy. Unexpectedly, the cooS1 inactivation strain showed a significantly reduced lag phase and a higher growth rate than the wild type on H2 and CO2. During heterotrophic growth on fructose, the acsA inactivation strain exhibited 61% reduced biomass and the abolishment of acetate production (a hallmark of acetogens, in favor of ethanol, lactate, and 2,3-butanediol production. A translational readthrough event was discovered in the uniquely truncated (compared to those of other acetogens C. autoethanogenum acsA gene. Insights gained from studying the function of CODH enhance the overall understanding of autotrophy and can be used for optimization of biotechnological production of ethanol and other commodities via gas fermentation.

  13. Aroma compounds generation in citrate metabolism of Enterococcus faecium: Genetic characterization of type I citrate gene cluster.

    Science.gov (United States)

    Martino, Gabriela P; Quintana, Ingrid M; Espariz, Martín; Blancato, Victor S; Magni, Christian

    2016-02-02

    Enterococcus is one of the most controversial genera belonging to Lactic Acid Bacteria. Research involving this microorganism reflects its dual behavior as regards its safety. Although it has also been associated to nosocomial infections, natural occurrence of Enterococcus faecium in food contributes to the final quality of cheese. This bacterium is capable of fermenting citrate, which is metabolized to pyruvate and finally derives in the production of the aroma compounds diacetyl, acetoin and 2,3 butanediol. Citrate metabolism was studied in E. faecium but no data about genes related to these pathways have been described. A bioinformatic approach allowed us to differentiate cit(-) (no citrate metabolism genes) from cit(+) strains in E. faecium. Furthermore, we could classify them according to genes encoding for the transcriptional regulator, the oxaloacetate decarboxylase and the citrate transporter. Thus we defined type I organization having CitI regulator (DeoR family), CitM cytoplasmic soluble oxaloacetate decarboxylase (Malic Enzyme family) and CitP citrate transporter (2-hydroxy-carboxylate transporter family) and type II organization with CitO regulator (GntR family), OAD membrane oxaloacetate decarboxylase complex (Na(+)-transport decarboxylase enzyme family) and CitH citrate transporter (CitMHS family). We isolated and identified 17 E. faecium strains from regional cheeses. PCR analyses allowed us to classify them as cit(-) or cit(+). Within the latter classification we could differentiate type I but no type II organization. Remarkably, we came upon E. faecium GM75 strain which carries the insertion sequence IS256, involved in adaptative and evolution processes of bacteria related to Staphylococcus and Enterococcus genera. In this work we describe the differential behavior in citrate transport, metabolism and aroma generation of three strains and we present results that link citrate metabolism and genetic organizations in E. faecium for the first time

  14. Enhanced H2 Production and Redirected Metabolic Flux via Overexpression of fhlA and pncB in Klebsiella HQ-3 Strain.

    Science.gov (United States)

    Jawed, Muhammad; Pi, Jian; Xu, Li; Zhang, Houjin; Hakeem, Abdul; Yan, Yunjun

    2016-03-01

    Genetic modifications are considered as one of the most important technologies for improving fermentative hydrogen yield. Herein, we overexpress fhlA and pncB genes from Klebsiella HQ-3 independently to enhance hydrogen molar yield. HQ-3-fhlA/pncB strain is developed by manipulation of pET28-Pkan/fhlA Kan(r) and pBBR1-MCS5/pncB Gm(r) as expression vectors to examine the synchronous effects of fhlA and pncB. Optimization of anaerobic batch fermentations is achieved and the maximum yield of biohydrogen (1.42 mol H2/mol of glucose) is produced in the range of pH 6.5-7.0 at 33-37 °C. Whole cell H2 yield is increased up to 40 % from HQ-3-fhlA/pncB, as compared with HQ-3-fhlA 20 % and HQ-3-pncB 12 % keeping HQ-3-C as a control. Mechanism of improved H2 yield is studied in combination with metabolic flux analysis by measuring glucose consumption and other metabolites including formate, succinate, 2,3 butanediol, lactate, acetate, ethanol, and hydrogen. The results suggest that under transient conditions, the increase in the total level of NAD by NAPRTase can enhance the rate of NADH-dependent pathways, and therefore, final distribution of metabolites is changed. Combined overexpression of fhlA and pncB eventually modifies the energy and carbon balance leading to enhanced H2 production from FHL as well as by NADH pathway.

  15. Bacillus amyloliquefaciens FZB42 repressed plant miR846 to induce systemic resistance via jasmonic acid-dependent signaling pathway.

    Science.gov (United States)

    Xie, Shanshan; Jiang, Haiyang; Ding, Ting; Xu, Qianqian; Chai, Wenbo; Cheng, Beijiu

    2017-11-01

    Bacillus amyloliquefaciens FZB42 is a kind of plant-growth-promoting rhizobacteria (PGPR) that activates induced systemic resistance (ISR) in Arabidopsis. Blocking in cyclic lipopeptides and 2,3-butanediol synthesis of FZB42, which were proved to be involved in priming ISR, resulted in abolishment of plant defense responses. To further clarify the ISR activated by PGPR at miRNA level, sRNA libraries from Arabidopsis leaves after root-irrigated with FZB42, FZB42ΔsfpΔalsS and control were constructed and sequenced. After fold-change selection, promoter analysis and target prediction, miR846-5p and miR846-3p from the same precursor were selected as candidate ISR-associated miRNA. miR846, belongs to non-conserved miRNAs, specifically exists in Arabidopsis and its function in plant defense response remains unclear. The disease severities of transgenic Arabidopsis overexpression miR846 (OEmiR846) and knockdown miR846 (STTM846) against Pseudomonas syringae DC3000 suggested that the miR846 expression level in Arabidopsis was negatively correlated with disease resistance. Moreover, miR846 in Arabidopsis Col-0 was repressed after methyl jasmonate treatment. In addition, jasmonic acid (JA) signaling related genes were up-regulated in STTM846 and stomatal apertures of STTM846 were also less than Arabidopsis Col-0 after methyl jasmonate treatment. Furthermore, the disease resistance of STTM846 transgenic Arabidopsis against pstDC3000 was blocked by adding JA biosynthetic inhibitor diethyldiethiocarbamic acid (DIECA). Taken together, our results suggested that Bacillus amyloliquefaciens FZB42 inoculation suppressed miR846 expression to induce Arabidopsis systemic resistance via JA-dependent signaling pathway. This article is protected by copyright. All rights reserved. © 2017 BSPP and John Wiley & Sons Ltd.

  16. Biosynthesis of poly(3-hydroxybutyrate) and its copolymers by Yangia sp. ND199 from different carbon sources.

    Science.gov (United States)

    Huu Phong, Tran; Van Thuoc, Doan; Sudesh, Kumar

    2016-03-01

    A halophilic bacterium isolated from mangrove soil sample in Northern Vietnam, Yangia sp. ND199 was found capable of producing homopolymer poly(3-hydroxybutyrate) [P(3HB)], copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)], and copolymer poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] from different carbon sources. The presence of 3HB, 3HV, and 4HB monomers were confirmed by gas chromatography and nuclear magnetic resonance analysis. Only P(3HB) was produced using carbon sources such as fructose or by a combination of fructose with 1,5-pentanediol, 1,6-hexanediol, sodium hexanoate, or sodium octanoate. The biosynthesis of P(3HB-co-3HV) was achieved by adding cosubstrates such as sodium valerate and sodium heptanoate. When 1,4-butanediol, γ-butyrolactone or sodium 4-hydroxybutyrate was added to the culture medium, P(3HB-co-4HB) containing 4.0-7.1mol% 4HB fraction was accumulated. The molecular weights and thermal properties of polyesters were determined by gel permeation chromatography and differential scanning calorimeter, respectively. The results showed that Yangia sp. ND199 is able to produce polyester with high weight average molecular weight ranging from 1.3×10(6) to 2.2×10(6) Dalton and number average molecular weight ranging from 4.2×10(5) to 6.9×10(5) Dalton. The molecular weights, glass transition temperature as well as melting temperature of homopolymer P(3HB) are higher than those of copolymer P(3HB-co-3HV) or P(3HB-co-4HB). Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Preparation and characterization of poly-(methacrylatoethyl trimethylammonium chloride-co-vinylbenzyl chloride-co-ethylene dimethacrylate monolith

    Directory of Open Access Journals (Sweden)

    Eko Malis

    2015-05-01

    Full Text Available A polymer monolithic column, poly-(methacrylatoethyltrimethylammonium chloride-co-vinylbenzyl chloride-co-ethylene dimethacrylate or poly-(MATE-co-VBC-co-EDMA was successfully prepared in the current study by one-step thermally initiated in situ polymerization, confined in a steel tubing of 0.5 mm i.d. and 1/16” o.d. The monoliths were prepared from methacrylatoethyltrimethylammonium chloride (MATE and vinylbenzyl chloride (VBC as monomer and ethylene dimethacrylate (EDMA as crosslinker using a binary porogen system of 1-propanol and 1,4-butanediol. The inner wall of steel tubing was pretreated with 3-methacryloxypropyl-trimethoxysilane (MAPS. In order to obtain monolith with adequate column efficiency and low flow resistance, some parameters such as total monomer concentration (%T and crosslinker concentration (%C were optimized. The morphology of this monolith was assessed by scanning electron microscopy (SEM. The properties of the monolithic column, such as permeability, binding capacity, and pore size distribution were also characterized in detail. From the results of the characterization of all monolith variation, monolith with %T 30 %C 50 and %T 35 %C 50 give the best characteristic. These monoliths have high permeability, adequate molecular recognition sites (represented with binding capacity value of over 20 mg/mL, and have over 80% flow through pores in their pore structure contribute to low flow resistance. The resulted monolithic columns have promising potential for dual mode liquid chromatography. MATE may contribute for anion-exchange while VBC may responsible for reversed-phase liquid chromatography.

  18. Acompanhamento do processo de fermentação para produção de cachaça através de métodos microbiológicos e físico-químicos com diferentes isolados de Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Thaís Louise Soares

    2011-03-01

    Full Text Available Com a crescente exigência do mercado consumidor por produtos de melhor qualidade, busca-se o constante aprimoramento da produção de cachaça, uma vez que todas as etapas da cadeia produtiva de bebidas fermento-destiladas são importantes. O objetivo deste trabalho foi acompanhar o processo de fermentação para produção de cachaça, utilizando diferentes isolados de Saccharomyces cerevisiae a partir da quantificação de metabólitos secundários por Cromatografia Gasosa. O acompanhamento do processo deu-se desde o preparo do inóculo até o final do processo fermentativo. O estudo foi conduzido na Universidade Federal de Lavras (UFLA. Foram utilizados 8 isolados de Saccharomyces cerevisiae inoculados em caldo de cana, dos quais foram retiradas amostras durante a fase de crescimento em sistema de batelada alimentada e fermentação. As amostras foram analisadas quanto à taxa de floculação, ºBrix e álcoois superiores. Os parâmetros avaliados apresentaram diferenças para cada isolado. O melhor isolado para a produção de cachaça foi o isolado UFLA CA116 por apresentar alto número de células viáveis, maior taxa de floculação, ausência 1-propanol, presença de 1,3 butanediol.

  19. Highly efficient bioreduction of 2-hydroxyacetophenone to (S)- and (R)-1-phenyl-1,2-ethanediol by two substrate tolerance carbonyl reductases with cofactor regeneration.

    Science.gov (United States)

    Cui, Zhi-Mei; Zhang, Jian-Dong; Fan, Xiao-Jun; Zheng, Gao-Wei; Chang, Hong-Hong; Wei, Wen-Long

    2017-02-10

    Optically pure 1-phenyl-1,2-ethanediol is a very important chiral building block and intermediate in fine chemical and pharmaceutical industries. Reduction of 2-hydroxyacetophenone provides a straightforward approach to access these important compounds. In this study, two enantiocomplementary carbonyl reductases, BDHA (2,3-butanediol dehydrogenase from Bacillus subtilis) and GoSCR (polyol dehydrogenase from Gluconobacter oxydans) were discovered for the first time to convert 2-hydroxyacetophenone (2-HAP) to (R)-1-phenyl-1,2-ethanediol ((R)-PED) and (S)-1-phenyl-1,2-ethanediol ((S)-PED) with excellent stereochemical selectivity, respectively. The two enzymes were purified and characterized. In vitro bioreduction of 2-HAP catalyzed by BDHA and GoSCR coupled with glucose dehydrogenase (GDH) from Bacillus subtilis for cofactor regeneration were demonstrated, affording both (R)-PED and (S)-PED in>99% ee and 99% conversion. Recombinant Escherichia coli whole cells co-expressing both GDH and BDHA or GoSCR genes were used to asymmetric reduction of 2-HAP to (R)-PED or (S)-PED. Under the optimized conditions, the bioreduction of 400mM (54g/L) substrate was proceeded smoothly without the external addition of cofactor, and the product (R)-PED and (S)-PED were obtained with 99% yield, >99% ee and 18.0g/L/h volumetric productivity. These results offer a practical biocatalytic method for the preparation of both (R)-PED and (S)-PED with high volumetric productivity. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Synthesis of waterborne polyurethane containing alkoxysilane side groups and the properties of the hybrid coating films

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qi; Guo, Longhai [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Qiu, Teng, E-mail: qiuteng@mail.buct.edu.cn [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Xiao, Weidong; Du, Dianxing [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Li, Xiaoyu, E-mail: lixy@mail.buct.edu.cn [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China)

    2016-07-30

    Highlights: • A diol with side-chain trimethoxysilane (DEA-Si) was synthesized using 3-(methacryloxypropyl)trimethoxysilane (MAPTS) and diethanolamine (DEA). • The crosslinking structure could in situ formed within the WPU matrix through sol-gel process. • The Si tends to shift to the polymer-air interface due to the flexible long alkyl-ester side chain. • The incorporation of DEA-Si enhanced mechanical and surface hydrophobic properties of WPU films. - Abstract: A series of waterborne polyurethane (WPU) containing alkoxysilane side groups were synthesized by using the dihydroxy functionalized alkoxysilane. The diol with trimethoxysilane groups at the side chains was synthesized via Michael addition between 3-(methacryloxypropyl)trimethoxysilane (MAPTS) and diethanolamine (DEA). The silane diol was applied as the chain extender for the NCO-endcapped prepolymer of isophorone diisocyanate, polycarbonate diol, 2,2-bis(hydroxymethyl) butyric acid and 1,4-butanediol. The products with the silane content varied from 1.2 to 16.5 wt% were dispersed in water after neutralization. The effect of the silane diol on the particle size and morphology of the WPU dispersion was studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. X-ray photoelectron spectroscopy (XPS) characterization was carried out on the coating film of the WPU, revealing that the long flexible side chain is favorable for the silane components to emigrate toward the film surface and crosslink during the film formation process. As a result, both the surface contact angle to water and water adsorption of the WPU coating films increased with the silane content. Furthermore, the mechanical properties including the modulus and tensile strength of the films were also improved by the incorporation of silane diol.

  1. A new crystal form of human tear lipocalin reveals high flexibility in the loop region and induced fit in the ligand cavity

    Energy Technology Data Exchange (ETDEWEB)

    Breustedt, Daniel A.; Chatwell, Lorenz; Skerra, Arne, E-mail: skerra@wzw.tum.de [Munich Center for Integrated Protein Science, CIPS-M, and Lehrstuhl für Biologische Chemie, Technische Universität München, 85350 Freising-Weihenstephan (Germany)

    2009-10-01

    The crystal structure of tear lipocalin determined in space group P2{sub 1} revealed large structural deviations from the previously solved X-ray structure in space group C2, especially in the loop region and adjoining parts of the β-barrel which give rise to the ligand-binding site. These findings illustrate a novel mechanism for promiscuity in ligand recognition by the lipocalin protein family. Tear lipocalin (TLC) with the bound artificial ligand 1,4-butanediol has been crystallized in space group P2{sub 1} with four protein molecules in the asymmetric unit and its X-ray structure has been solved at 2.6 Å resolution. TLC is a member of the lipocalin family that binds ligands with diverse chemical structures, such as fatty acids, phospholipids and cholesterol as well as microbial siderophores and the antibiotic rifampin. Previous X-ray structural analysis of apo TLC crystallized in space group C2 revealed a rather large bifurcated ligand pocket and a partially disordered loop region at the entrace to the cavity. Analysis of the P2{sub 1} crystal form uncovered major conformational changes (i) in β-strands B, C and D, (ii) in loops 1, 2 and 4 at the open end of the β-barrel and (iii) in the extended C-terminal segment, which is attached to the β-barrel via a disulfide bridge. The structural comparison indicates high conformational plasticity of the loop region as well as of deeper parts of the ligand pocket, thus allowing adaptation to ligands that differ vastly in size and shape. This illustrates a mechanism for promiscuity in ligand recognition which may also be relevant for some other physiologically important members of the lipocalin protein family.

  2. Polyethylenimine modified poly(ethylene terephthalate) capillary channeled-polymer fibers for anion exchange chromatography of proteins.

    Science.gov (United States)

    Jiang, Liuwei; Jin, Yi; Marcus, R Kenneth

    2015-09-04

    Native poly(ethylene terephthalate) (PET) capillary-channeled polymer (C-CP) fibers have been previously studied as stationary phases for reversed phase and affinity protein separations. In this study, surface modified PET C-CP fibers were evaluated for the anion exchange separation of proteins. The native PET C-CP fibers were aminated using polyethylenimine (PEI) followed by a 1,4-butanediol diglycidyl ether (BUDGE) cross-linking step. Subsequent PEI/BUDGE treatments can be employed to further develop the polyamine layer on the fiber surfaces. The PEI densities of the modified fibers were quantified through the ninhydrin reaction, yielding values of 0.43-0.89μmolg(-1). The surface modification impact on column permeability was found to be 0.66×10(-11) to 1.33×10(-11)m(2), depending on the modification time and conditions. The dynamic binding capacities of the modified fiber media were determined to be 1.99-8.54mgmL(-1) bed volume, at linear velocities of 88-438cmmin(-1) using bovine serum albumin as the model protein. It was found that increasing the mobile phase linear velocity (up to 438cmmin(-1)) had no effect on the separation quality for a synthetic protein mixture, reflecting the lack of van Deemter C-term effects for the C-CP fiber phase. The low-cost, easy modification method and the capability of fast protein separation illustrate great potential in the use of PEI/BUDGE-modified PET C-CP fibers for high-throughput protein separation and downstream processing. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Surface and buried interfacial structures of epoxy resins used as underfills studied by sum frequency generation vibrational spectroscopy.

    Science.gov (United States)

    Vázquez, Anne V; Holden, Brad; Kristalyn, Cornelius; Fuller, Mike; Wilkerson, Brett; Chen, Zhan

    2011-05-01

    Flip chip technology has greatly improved the performance of semiconductor devices, but relies heavily on the performance of epoxy underfill adhesives. Because epoxy underfills are cured in situ in flip chip semiconductor devices, understanding their surface and interfacial structures is critical for understanding their adhesion to various substrates. Here, sum frequency generation (SFG) vibrational spectroscopy was used to study surface and buried interfacial structures of two model epoxy resins used as underfills in flip chip devices, bisphenol A digylcidyl ether (BADGE) and 1,4-butanediol diglycidyl ether (BDDGE). The surface structures of these epoxies were compared before and after cure, and the orientations of their surface functional groups were deduced to understand how surface structural changes during cure may affect adhesion properties. Further, the effect of moisture exposure, a known cause of adhesion failure, on surface structures was studied. It was found that the BADGE surface significantly restructured upon moisture exposure while the BDDGE surface did not, showing that BADGE adhesives may be more prone to moisture-induced delamination. Lastly, although surface structure can give some insight into adhesion, buried interfacial structures more directly correspond to adhesion properties of polymers. SFG was used to study buried interfaces between deuterated polystyrene (d-PS) and the epoxies before and after moisture exposure. It was shown that moisture exposure acted to disorder the buried interfaces, most likely due to swelling. These results correlated with lap shear adhesion testing showing a decrease in adhesion strength after moisture exposure. The presented work showed that surface and interfacial structures can be correlated to adhesive strength and may be helpful in understanding and designing optimized epoxy underfill adhesives.

  4. Production of Succinic Acid for Lignocellulosic Hydrolysates

    Energy Technology Data Exchange (ETDEWEB)

    Davison, B.H.; Nghiem, J.

    2002-06-01

    The purpose of this Cooperative Research and Development Agreement (CRADA) is to add and test new metabolic activities to existing microbial catalysts for the production of succinic acid from renewables. In particular, they seek to add to the existing organism the ability to utilize xylose efficiently and simultaneously with glucose in mixtures of sugars or to add succinic acid production to another strain and to test the value of this new capability for production of succinic acid from industrial lignocellulosic hydrolyasates. The Contractors and Participant are hereinafter jointly referred to as the 'Parties'. Research to date in succinic acid fermentation, separation and genetic engineering has resulted in a potentially economical process based on the use of an Escherichia coli strain AFP111 with suitable characteristics for the production of succinic acid from glucose. Economic analysis has shown that higher value commodity chemicals can be economically produced from succinic acid based on repliminary laboratory findings and predicted catalytic parameters. The initial target markets include succinic acid itself, succinate salts, esters and other derivatives for use as deicers, solvents and acidulants. The other commodity products from the succinic acid platform include 1,4-butanediol, {gamma}-butyrolactone, 2-pyrrolidinone and N-methyl pyrrolidinone. Current economic analyses indicate that this platform is competitive with existing petrochemical routes, especially for the succinic acid and derivatives. The report presents the planned CRADA objectives followed by the results. The results section has a combined biocatalysis and fermentation section and a commercialization section. This is a nonproprietary report; additional proprietary information may be made available subject to acceptance of the appropriate proprietary information agreements.

  5. Combining CRISPR and CRISPRi Systems for Metabolic Engineering of E. coli and 1,4-BDO Biosynthesis.

    Science.gov (United States)

    Wu, Meng-Ying; Sung, Li-Yu; Li, Hung; Huang, Chun-Hung; Hu, Yu-Chen

    2017-12-15

    Biosynthesis of 1,4-butanediol (1,4-BDO) in E. coli requires an artificial pathway that involves six genes and time-consuming, iterative genome engineering. CRISPR is an effective gene editing tool, while CRISPR interference (CRISPRi) is repurposed for programmable gene suppression. This study aimed to combine both CRISPR and CRISPRi for metabolic engineering of E. coli and 1,4-BDO production. We first exploited CRISPR to perform point mutation of gltA, replacement of native lpdA with heterologous lpdA, knockout of sad and knock-in of two large (6.0 and 6.3 kb in length) gene cassettes encoding the six genes (cat1, sucD, 4hbd, cat2, bld, bdh) in the 1,4-BDO biosynthesis pathway. The successive E. coli engineering enabled production of 1,4-BDO to a titer of 0.9 g/L in 48 h. By combining the CRISPRi system to simultaneously suppress competing genes that divert the flux from the 1,4-BDO biosynthesis pathway (gabD, ybgC and tesB) for >85%, we further enhanced the 1,4-BDO titer for 100% to 1.8 g/L while reducing the titers of byproducts gamma-butyrolactone and succinate for 55% and 83%, respectively. These data demonstrate the potential of combining CRISPR and CRISPRi for genome engineering and metabolic flux regulation in microorganisms such as E. coli and production of chemicals (e.g., 1,4-BDO).

  6. Chemical and enzymatic catalytic routes to polyesters and oligopeptides biobased materials

    Science.gov (United States)

    Zhu, Jianhui

    My Ph.D research focuses on the synthesis and property studies of different biobased materials, including polyesters, polyurethanes and oligopeptides. The first study describes the synthesis, crystal structure and physico-mechanical properties of a bio-based polyester prepared from 2,5-furandicarboxylic acid (FDCA) and 1,4-butanediol. Melt-polycondensation experiments were conducted by a two-stage polymerization using titanium tetraisopropoxide (Ti[OiPr] 4) as catalyst. Polymerization conditions (catalyst concentration, reaction time and 2nd stage reaction temperature) were varied to optimize poly(butylene furan dicarboxylate), PBF, molecular weight. A series of PBFs with different Mw were characterized by Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Dynamic Mechanical Thermal Analysis (DMTA), X-Ray diffraction and tensile testing. Influence of molecular weight and melting/crystallization enthalpy on PBF material tensile properties was explored. Cold-drawing tensile tests at room temperature for PBF with Mw 16K to 27K showed a brittle-to-ductile transition. When Mw reaches 38K, the Young's Modulus of PBF remains above 900 MPa, and the elongation at break increases to above 1000%. The mechanical properties, thermal properties and crystal structures of PBF were similar to petroleum derived poly(butylenes terephthalate), PBT. Fiber diagrams of uniaxially stretched PBF films were collected, indexed, and the unit cell was determined as triclinic (a=4.78(3) A, b=6.03(5) A, c=12.3(1) A, alpha=110.1(2)°, beta=121.1(3)°, gamma=100.6(2)°). A crystal structure was derived from this data and final atomic coordinates are reported. We concluded that there is a close similarity of the PBF structure to PBT alpha- and beta-forms. In the second study, a biobased long chain polyester polyol (PC14-OH) was synthesized from o-hydroxytetradecanoic acid (o-HOC14) and 1,4-butanediol. The first section about polyester polyurethanes describes the synthesis

  7. Chromatographic assessment of two hybrid monoliths prepared via epoxy-amine ring-opening polymerization and methacrylate-based free radical polymerization using methacrylate epoxy cyclosiloxane as functional monomer.

    Science.gov (United States)

    Wang, Hongwei; Ou, Junjie; Lin, Hui; Liu, Zhongshan; Huang, Guang; Dong, Jing; Zou, Hanfa

    2014-11-07

    Two kinds of hybrid monolithic columns were prepared by using methacrylate epoxy cyclosiloxane (epoxy-MA) as functional monomer, containing three epoxy moieties and one methacrylate group. One column was in situ fabricated by ring-opening polymerization of epoxy-MA and 1,10-diaminodecane (DAD) using a porogenic system consisting of isopropanol (IPA), H2O and ethanol at 65°C for 12h. The other was prepared by free radical polymerization of epoxy-MA and ethylene dimethacrylate (EDMA) using 1-propanol and 1,4-butanediol as the porogenic solvents at 60°C for 12h. Two hybrid monoliths were investigated on the morphology and chromatographic assessment. Although two kinds of monolithic columns were prepared with epoxy-MA, their morphologies looked rather different. It could be found that the epoxy-MA-DAD monolith possessed higher column efficiencies (25,000-34,000plates/m) for the separation of alkylbenzenes than the epoxy-MA-EDMA monolith (12,000-13,000plates/m) in reversed-phase nano-liquid chromatography (nano-LC). Depending on the remaining epoxy or methacrylate groups on the surface of two pristine monoliths, the epoxy-MA-EDMA monolith could be easily modified with 1-octadecylamine (ODA) via ring-opening reaction, while the epoxy-MA-DAD monolith could be modified with stearyl methacrylate (SMA) via free radical reaction. The chromatographic performance for the separation of alkylbenzenes on SMA-modified epoxy-MA-DAD monolith was remarkably improved (42,000-54,000 plates/m) when compared with that on pristine epoxy-MA-DAD monolith, while it was not obviously enhanced on ODA-modified epoxy-MA-EDMA monolith when compared with that on pristine epoxy-MA-EDMA monolith. The enhancement of the column efficiency of epoxy-MA-DAD monolith after modification might be ascribed to the decreased mass-transfer resistence. The two kinds of hybrid monoliths were also applied for separations of six phenols and seven basic compounds in nano-LC. Copyright © 2014 Elsevier B.V. All

  8. Deaths in the Lesbian, Gay, Bisexual and Transgender United Kingdom communities associated with GHB and precursors.

    Science.gov (United States)

    Corkery, John M; Loi, Barbara; Claridge, Hugh; Goodair, Christine; Schifano, Fabrizio

    2017-11-08

    Background Misuse of gammahydroxybutrate (GHB) and its prodrugs gammabutyrolactone (GBL) and 1,4 butanediol (1,4-BD) has increased greatly since the early 1990s, particularly amongst lesbian, gay, bisexual and transgender (LGBT) individuals in recreational and sexual settings, e.g. 'chemsex'. Objective and method This paper presents an overview of GHB pharmacotoxicology and provides analyses of cases in the LGBT population associated with use of these substances extracted from the UK's National Programme on Substance Abuse Deaths database, to which notification is voluntary. Results From 1995 to September 2013, 21 GHB/GBL-associated fatalities were reported. None involved 1,4-BD. Typical victims were: Male (100%); White (67%), young (mean age 34 years); employed (90%); with a drug misuse history (81%). Most deaths were accidental (67%) or related to recreational drug use (19%), the remaining (potential) suicides. The majority of fatalities (83%) occurred in private residences, typically following recreational use; others occurred in specific 'gay'-oriented locales including clubs and saunas. Three London boroughs accounted for 62% of all notified deaths, reflecting the concentration of both resident and visiting 'gay' individuals. However, this may be an artefact of the voluntary nature of the data submission procedure in particular areas. GHB/GBL alone was implicated in 10% of fatalities. The following substances were implicated either alone or in combination in the remaining cases (percentages may add to more than 100%): cocaine (38%); alcohol (33%); amphetamines (29%); ecstasy (29%); diazepam (24%); ketamine (24%); mephedrone (24%). Post-mortem blood levels: mean 660 (range 22 - 2335; S.D. 726) mg/L. Conclusions Significant caution is needed when ingesting GHB/GBL, particularly with alcohol, benzodiazepines, stimulants, and ketamine. Risk of death is increased due to their CNS-depressant properties. Of these, 'chemsex' drugs such as cocaine, mephedrone and

  9. Airborne measurements of organosulfates over the continental U.S.

    Science.gov (United States)

    Liao, Jin; Froyd, Karl D; Murphy, Daniel M; Keutsch, Frank N; Yu, Ge; Wennberg, Paul O; St Clair, Jason M; Crounse, John D; Wisthaler, Armin; Mikoviny, Tomas; Jimenez, Jose L; Campuzano-Jost, Pedro; Day, Douglas A; Hu, Weiwei; Ryerson, Thomas B; Pollack, Ilana B; Peischl, Jeff; Anderson, Bruce E; Ziemba, Luke D; Blake, Donald R; Meinardi, Simone; Diskin, Glenn

    2015-01-01

    Organosulfates are important secondary organic aerosol (SOA) components and good tracers for aerosol heterogeneous reactions. However, the knowledge of their spatial distribution, formation conditions, and environmental impact is limited. In this study, we report two organosulfates, an isoprene-derived isoprene epoxydiols (IEPOX) (2,3-epoxy-2-methyl-1,4-butanediol) sulfate and a glycolic acid (GA) sulfate, measured using the NOAA Particle Analysis Laser Mass Spectrometer (PALMS) on board the NASA DC8 aircraft over the continental U.S. during the Deep Convective Clouds and Chemistry Experiment (DC3) and the Studies of Emissions and Atmospheric Composition, Clouds, and Climate Coupling by Regional Surveys (SEAC4RS). During these campaigns, IEPOX sulfate was estimated to account for 1.4% of submicron aerosol mass (or 2.2% of organic aerosol mass) on average near the ground in the southeast U.S., with lower concentrations in the western U.S. (0.2–0.4%) and at high altitudes (<0.2%). Compared to IEPOX sulfate, GA sulfate was more uniformly distributed, accounting for about 0.5% aerosol mass on average, and may be more abundant globally. A number of other organosulfates were detected; none were as abundant as these two. Ambient measurements confirmed that IEPOX sulfate is formed from isoprene oxidation and is a tracer for isoprene SOA formation. The organic precursors of GA sulfate may include glycolic acid and likely have both biogenic and anthropogenic sources. Higher aerosol acidity as measured by PALMS and relative humidity tend to promote IEPOX sulfate formation, and aerosol acidity largely drives in situ GA sulfate formation at high altitudes. This study suggests that the formation of aerosol organosulfates depends not only on the appropriate organic precursors but also on emissions of anthropogenic sulfur dioxide (SO2), which contributes to aerosol acidity. Key Points IEPOX sulfate is an isoprene SOA tracer at acidic and low NO conditions Glycolic acid sulfate

  10. Comparative genomic analysis of single-molecule sequencing and hybrid approaches for finishing the Clostridium autoethanogenum JA1-1 strain DSM 10061 genome

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Steven D [ORNL; Nagaraju, Shilpa [LanzaTech; Utturkar, Sagar M [ORNL; De Tissera, Sashini [LanzaTech; Segovia, Simón [LanzaTech; Mitchell, Wayne [LanzaTech; Land, Miriam L [ORNL; Dassanayake, Asela [LanzaTech; Köpke, Michael [LanzaTech

    2014-01-01

    Background Clostridium autoethanogenum strain JA1-1 (DSM 10061) is an acetogen capable of fermenting CO, CO2 and H2 (e.g. from syngas or waste gases) into biofuel ethanol and commodity chemicals such as 2,3-butanediol. A draft genome sequence consisting of 100 contigs has been published. Results A closed, high-quality genome sequence for C. autoethanogenum DSM10061 was generated using only the latest single-molecule DNA sequencing technology and without the need for manual finishing. It is assigned to the most complex genome classification based upon genome features such as repeats, prophage, nine copies of the rRNA gene operons. It has a low G + C content of 31.1%. Illumina, 454, Illumina/454 hybrid assemblies were generated and then compared to the draft and PacBio assemblies using summary statistics, CGAL, QUAST and REAPR bioinformatics tools and comparative genomic approaches. Assemblies based upon shorter read DNA technologies were confounded by the large number repeats and their size, which in the case of the rRNA gene operons were ~5 kb. CRISPR (Clustered Regularly Interspaced Short Paloindromic Repeats) systems among biotechnologically relevant Clostridia were classified and related to plasmid content and prophages. Potential associations between plasmid content and CRISPR systems may have implications for historical industrial scale Acetone-Butanol-Ethanol (ABE) fermentation failures and future large scale bacterial fermentations. While C. autoethanogenum contains an active CRISPR system, no such system is present in the closely related Clostridium ljungdahlii DSM 13528. A common prophage inserted into the Arg-tRNA shared between the strains suggests a common ancestor. However, C. ljungdahlii contains several additional putative prophages and it has more than double the amount of prophage DNA compared to C. autoethanogenum. Other differences include important metabolic genes for central metabolism (as an additional hydrogenase and the absence of a

  11. Evolution of the metabolic and regulatory networks associated with oxygen availability in two phytopathogenic enterobacteria.

    Science.gov (United States)

    Babujee, Lavanya; Apodaca, Jennifer; Balakrishnan, Venkatesh; Liss, Paul; Kiley, Patricia J; Charkowski, Amy O; Glasner, Jeremy D; Perna, Nicole T

    2012-03-22

    Dickeya dadantii and Pectobacterium atrosepticum are phytopathogenic enterobacteria capable of facultative anaerobic growth in a wide range of O2 concentrations found in plant and natural environments. The transcriptional response to O2 remains under-explored for these and other phytopathogenic enterobacteria although it has been well characterized for animal-associated genera including Escherichia coli and Salmonella enterica. Knowledge of the extent of conservation of the transcriptional response across orthologous genes in more distantly related species is useful to identify rates and patterns of regulon evolution. Evolutionary events such as loss and acquisition of genes by lateral transfer events along each evolutionary branch results in lineage-specific genes, some of which may have been subsequently incorporated into the O2-responsive stimulon. Here we present a comparison of transcriptional profiles measured using densely tiled oligonucleotide arrays for two phytopathogens, Dickeya dadantii 3937 and Pectobacterium atrosepticum SCRI1043, grown to mid-log phase in MOPS minimal medium (0.1% glucose) with and without O2. More than 7% of the genes of each phytopathogen are differentially expressed with greater than 3-fold changes under anaerobic conditions. In addition to anaerobic metabolism genes, the O2 responsive stimulon includes a variety of virulence and pathogenicity-genes. Few of these genes overlap with orthologous genes in the anaerobic stimulon of E. coli. We define these as the conserved core, in which the transcriptional pattern as well as genetic architecture are well preserved. This conserved core includes previously described anaerobic metabolic pathways such as fermentation. Other components of the anaerobic stimulon show variation in genetic content, genome architecture and regulation. Notably formate metabolism, nitrate/nitrite metabolism, and fermentative butanediol production, differ between E. coli and the phytopathogens. Surprisingly, the

  12. Preparation of a polymeric ionic liquid-based adsorbent for stir cake sorptive extraction of preservatives in orange juices and tea drinks

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Lei; Huang, Xiaojia, E-mail: hxj@xmu.edu.cn

    2016-04-15

    In this study, a new polymeric ionic liquid-based adsorbent was prepared and used as the extraction medium of stir cake sorptive extraction (SCSE) of three organic acid preservatives, namely, p-hydroxybenzoic acid, sorbic acid and cinnamic acid. The adsorbent was synthesized by the copolymerization of 1-ally-3-vinylimidazolium chloride (AV) and divinylbenzene (DVB) in the presence of a porogen solvent containing 1-propanol and 1,4-butanediol. The effect of the content of monomer and the porogen solvent in the polymerization mixture on the extraction performance was investigated thoroughly. The adsorbent was characterized by infrared spectroscopy, elemental analysis, scanning electron microscopy and mercury intrusion porosimetry. To obtain the optimal extraction conditions of SCSE/AVDVB for target analytes, key parameters including desorption solvent, adsorption and desorption time, ionic strength and pH value in sample matrix were studied in detail. The results showed that under the optimized conditions, the SCSE/AVDVB could extract the preservatives effectively through multiply interactions. At the same time, a simple and sensitive method by combining SCSE/AVDVB and high-performance liquid chromatography with diode array detection was developed for the simultaneous analysis of the target preservatives in orange juices and tea drinks. Low limits of detection (S/N = 3) and quantification limits (S/N = 10) of the proposed method for the target analytes were achieved within the range of 0.012–0.23 μg/L and 0.039–0.42 μg/L, respectively. The precision of the proposed method was evaluated in terms of intra- and inter-assay variability calculated as relative standard deviation (RSD), and it was found that the values were all below 10%. Finally, the proposed method was used to detect preservatives in different orange juice and tea drink samples successfully. The recoveries were in the range of 71.9–116%, and the RSDs were below 10% in the all cases

  13. Molecular Chirality: Enantiomer Differentiation by High-Resolution Spectroscopy

    Science.gov (United States)

    Hirota, Eizi

    2014-06-01

    I have demonstrated that triple resonance performed on a three-rotational-level system of a chiral molecule of C1 symmetry exhibits signals opposite in phase for different enantiomers, thereby making enantiomer differentiation possible by microwave spectroscopy This prediction was realized by Patterson et al. on 1,2-propanediol and 1,3-butanediol. We thus now add a powerful method: microwave spectroscopy to the study of chiral molecules, for which hitherto only the measurement of optical rotation has been employed. Although microwave spectroscopy is applied to molecules in the gaseous phase, it is unprecedentedly superior to the traditional method: polarimeter in resolution, accuracy, sensitivity, and so on, and I anticipate a new fascinating research area to be opened in the field of molecular chirality. More versatile and efficient systems should be invented and developed for microwave spectroscopy, in order to cope well with new applications expected for this method For C2 and Cn (n ≥ 3)chiral molecules, the three-rotational-level systems treated above for C1 molecules are no more available within one vibronic state. It should, however, be pointed out that, if we take into account an excited vibronic state in addition to the ground state, for example, we may encounter many three-level systems. Namely, either one rotational transition in the ground state is combined with two vibronic transitions, or such a rotational transition in an excited state may be connected through two vibronic transitions to a rotational level in the ground state manifold. The racemization obviously plays a crucial role in the study of molecular chirality. However, like many other terms employed in chemistry, this important process has been "defined" only in a vague way, in other words, it includes many kinds of processes, which are not well classified on a molecular basis. I shall mention an attempt to obviate these shortcomings in the definition of racemization and also to clarify the

  14. The effect of hydroxyl functional groups and molar mass on the viscosity of non-crystalline organic and organic-water particles

    Science.gov (United States)

    Grayson, James W.; Evoy, Erin; Song, Mijung; Chu, Yangxi; Maclean, Adrian; Nguyen, Allena; Upshur, Mary Alice; Ebrahimi, Marzieh; Chan, Chak K.; Geiger, Franz M.; Thomson, Regan J.; Bertram, Allan K.

    2017-07-01

    The viscosities of three polyols and three saccharides, all in the non-crystalline state, have been studied. Two of the polyols (2-methyl-1,4-butanediol and 1,2,3-butanetriol) were studied under dry conditions, the third (1,2,3,4-butanetetrol) was studied as a function of relative humidity (RH), including under dry conditions, and the saccharides (glucose, raffinose, and maltohexaose) were studied as a function of RH. The mean viscosities of the polyols under dry conditions range from 1.5 × 10-1 to 3.7 × 101 Pa s, with the highest viscosity being that of the tetrol. Using a combination of data determined experimentally here and literature data for alkanes, alcohols, and polyols with a C3 to C6 carbon backbone, we show (1) there is a near-linear relationship between log10 (viscosity) and the number of hydroxyl groups in the molecule, (2) that on average the addition of one OH group increases the viscosity by a factor of approximately 22 to 45, (3) the sensitivity of viscosity to the addition of one OH group is not a strong function of the number of OH functional groups already present in the molecule up to three OH groups, and (4) higher sensitivities are observed when the molecule has more than three OH groups. Viscosities reported here for 1,2,3,4-butanetetrol particles are lower than previously reported measurements using aerosol optical tweezers, and additional studies are required to resolve these discrepancies. For saccharide particles at 30 % RH, viscosity increases by approximately 2-5 orders of magnitude as molar mass increases from 180 to 342 g mol-1, and at 80 % RH, viscosity increases by approximately 4-5 orders of magnitude as molar mass increases from 180 to 991 g mol-1. These results suggest oligomerization of highly oxidized compounds in atmospheric secondary organic aerosol (SOA) could lead to large increases in viscosity, and may be at least partially responsible for the high viscosities observed in some SOA. Finally, two quantitative structure

  15. The novel silicon-containing epoxy/PEPA phosphate flame retardant for transparent intumescent fire resistant coating

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yanchao [School of Materials Science and Engineering, Tongji University, 4800 Cao' an Road, Shanghai 201804 (China); Wang, Guojian, E-mail: wanggj@tongji.edu.cn [School of Materials Science and Engineering, Tongji University, 4800 Cao' an Road, Shanghai 201804 (China); Key Laboratory of Advanced Civil Engineering Materials, Ministry of Education, 4800 Cao' an Road, Shanghai 201804 (China)

    2016-11-01

    Highlights: • The novel halogen-free flame retardant containing silicon and caged bicyclic phosphate was synthesized. • A novel transparent intumescent fire resistant coating was developed by the P-Si synergistic flame retardant and melamine formaldehyde resin. • Excellent fire protection of the transparent intumescent fire resistant coating. • The P-Si synergistic flame retardant could improve the thermo-oxidation resistance of transparent fire resistant coating. - Abstract: A series of novel silicon-containing epoxy/PEPA phosphate flame retardants (EPPSi) were synthesized by polyphosphoric acid (PPA), caged bicyclic phosphate 1-oxo-4-hydroxymethyl-2,6,7-trioxa-L-phosphabicyclo [2.2.2] octane (PEPA), and different ratios of silicon-containing epoxy 1,1,3,3-tetramethyl-1,3-bis(3-(oxiran-2-ylmethoxy)propyl)disiloxane (TMSEP) to 1,4-butanediol diglycidyl ether (BDE). The chemical structure of EPPSi was confirmed by Fourier transform infrared spectroscopy (FTIR) and {sup 1}H nuclear magnetic resonance spectroscopy ({sup 1}H NMR). Afterwards, the transparent intumescent fire resistant coatings were prepared by mixing EPPSi and melamine formaldehyde resin. The influence of silicon on the fire protection of coatings was intensively investigated by fire protection test, intumescence ratio, scanning electron microscope (SEM), compressive strength test, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and real-time FTIR. It was found that the fire resistant coatings obtained the best fire protection when the ratio of TMESP/BDE was 20/100, while excessive TMSEP made the fire protection of coatings deceased sharply. The intumescence ratio, compressive strength test and SEM result showed that a synergistic effect existed between phosphorus and silicon, which improved the foam structure and compressive strength of the char layer significantly. XPS result proved the out-migration effect of silicon. The high concentration silicon on surface played

  16. Early adaptation to oxygen is key to the industrially important traits of Lactococcus lactis ssp. cremoris during milk fermentation.

    Science.gov (United States)

    Cretenet, Marina; Le Gall, Gwenaëlle; Wegmann, Udo; Even, Sergine; Shearman, Claire; Stentz, Régis; Jeanson, Sophie

    2014-12-03

    Lactococcus lactis is the most used species in the dairy industry. Its ability to adapt to technological stresses, such as oxidative stress encountered during stirring in the first stages of the cheese-making process, is a key factor to measure its technological performance. This study aimed to understand the response to oxidative stress of Lactococcus lactis subsp. cremoris MG1363 at the transcriptional and metabolic levels in relation to acidification kinetics and growth conditions, especially at an early stage of growth. For those purposes, conditions of hyper-oxygenation were initially fixed for the fermentation. Kinetics of growth and acidification were not affected by the presence of oxygen, indicating a high resistance to oxygen of the L. lactis MG1363 strain. Its resistance was explained by an efficient consumption of oxygen within the first 4 hours of culture, leading to a drop of the redox potential. The efficient consumption of oxygen by the L. lactis MG1363 strain was supported by a coherent and early adaptation to oxygen after 1 hour of culture at both gene expression and metabolic levels. In oxygen metabolism, the over-expression of all the genes of the nrd (ribonucleotide reductases) operon or fhu (ferrichrome ABC transports) genes was particularly significant. In carbon metabolism, the presence of oxygen led to an early shift at the gene level in the pyruvate pathway towards the acetate/2,3-butanediol pathway confirmed by the kinetics of metabolite production. Finally, the MG1363 strain was no longer able to consume oxygen in the stationary growth phase, leading to a drastic loss of culturability as a consequence of cumulative stresses and the absence of gene adaptation at this stage. Combining metabolic and transcriptomic profiling, together with oxygen consumption kinetics, yielded new insights into the whole genome adaptation of L. lactis to initial oxidative stress. An early and transitional adaptation to oxidative stress was revealed for L

  17. Exogenous ketone supplements reduce anxiety-related behavior in Sprague-Dawley and Wistar Albino Glaxo/Rijswijk rats

    Directory of Open Access Journals (Sweden)

    Csilla Ari

    2016-12-01

    Full Text Available Nutritional ketosis has been proven effective for seizure disorders and other neurological disorders. The focus of this study was to determine the effects of ketone supplementation on anxiety-related behavior in Sprague-Dawley (SPD and Wistar Albino Glaxo/Rijswijk (WAG/Rij rats. We tested exogenous ketone supplements added to food and fed chronically for 83 days in SPD rats and administered sub-chronically for 7 days in both rat models by daily intragastric gavage bolus followed by assessment of anxiety measures on elevated plus maze (EPM. The groups included standard diet (SD or SD + ketone supplementation. Low-dose ketone ester (LKE (1,3-butanediol-acetoacetate diester, ~10 g/kg/day, LKE, high dose ketone ester (HKE (~25 g/kg/day, HKE, beta-hydroxybutyrate-mineral salt (βHB-S (~25 g/kg/day, KS, and βHB-S + medium chain triglyceride (MCT (~25 g/kg/day, KSMCT were used as ketone supplementation for chronic administration. To extend our results, exogenous ketone supplements were also tested sub-chronically on SPD rats (KE, KS and KSMCT; 5 g/kg/day and on WAG/Rij rats (KE, KS and KSMCT; 2.5 g/kg/day. At the end of treatments behavioral data collection was conducted manually by a blinded observer and with a video-tracking system, after which blood βHB and glucose levels were measured. Ketone supplementation reduced anxiety on EPM as measured by less entries to closed arms (sub-chronic KE and KS: SPD rats and KSMCT: WAG/Rij rats, more time spent in open arms (sub-chronic KE: SPD and KSMCT: WAG/Rij rats; chronic KSMCT: SPD rats, more distance travelled in open arms (chronic KS and KSMCT: SPD rats, and by delayed latency to entrance to closed arms (chronic KSMCT: SPD rats, when compared to control. Our data indicates that chronic and sub-chronic ketone supplementation not only elevated blood βHB levels in both animal models, but reduced anxiety-related behavior. We conclude that ketone supplementation may represent a promising anxiolytic strategy

  18. Total synthesis of macrodiolide ionophores aplasmomycin A and boromycin via double ring contraction.

    Science.gov (United States)

    Avery, Mitchell A; Choudhry, Satish C; Dhingra, Om Prakash; Gray, Brian D; Kang, Myung-chol; Kuo, Shen-chun; Vedananda, Thalathani R; White, James D; Whittle, Alan J

    2014-12-07

    The half structure of the symmetrical macrodiolide aplasmomycin A was synthesized by alkylation of a C3-C10 α-sulfonyl ketone subunit, prepared from (R)-pulegone and protected as a C3 ortholactone with (2R,3R)-butanediol, by a protected 15,16-dihydroxy (12E)-allylic chloride representing C11-C17. The latter was obtained from (2S,3R)-1,2-epoxy-3-butanol and propargyl alcohol. Regio- and stereoselective 5-exo-trig cyclization of the ene diol moiety in this segment, mediated by N-bromosuccinimide, led to the (2R,3S,5R)-tetrahydrofuran substructure of aplasmomycin A. Attachment of an α-acetic ester at the C3 carboxylic acid and esterification of the 3'-hydroxyl group of the tetrahydrofuran as its α-bromoacetate enabled coupling of two aplasmomycin half structures as an α-acyloxy acetate. Mukaiyama macrolactonization of this hydroxy acid afforded a symmetrical 36-membered diolide. Base-mediated double Chan rearrangement of this bis α-acyloxy dilactone caused ring contraction to the 34-membered macrocycle of desboroaplasmomycin A while generating the transannular 2-hydroxy-3-hemiketal motif of the natural product in the correct configuration. Final incorporation of boron into the tetraol core produced aplasmomycin A, isolated as its sodium borate. Extension of this route to the unsymmetrical macrodiolide boromycin was accomplished by modifications that included reversal of C12-C13 olefin geometry to (Z) for the southern half structure along with stereoselective hydride reductions of the C9 ketone that produced (9R) and (9S) alcohols for northern and southern half structures, respectively. Coupling of these half structures was made using an α-acyloxy ester linkage as for aplasmomycin A, but ring closure in this case was orchestrated via a blocked C16 alcohol that left open the C15 hydroxyl group of the southern half for Mukaiyama macrolactonization. A double Chan rearrangement of the resulting 35-membered macrocycle produced the 33-membered diolide of

  19. Polyurethane-based polymer surface modifiers with alkyl ammonium copolyoxetane soft segments: Reaction engineering, surface morphology and antimicrobial behavior

    Science.gov (United States)

    Brunson, Kennard Marcellus, Jr.

    Concentrating quaternary (positive) charge at polymer surfaces is important for applications including layer-by-layer polyelectrolyte deposition and antimicrobial coatings. Prior techniques to introduce quaternary charge to the surface involve grafting of quaternary ammonium moieties to a substrate or using polyurethanes with modified hard segments however there are impracticalities involved with these techniques. In the case of the materials discussed, the quaternary charge is introduced via polyurethane based polymer surface modifiers (PSMs) with quaternized soft segments. The particular advantage to this method is that it utilizes the intrinsic phase separation between the hard and soft segments of polyurethanes. This phase separation results in the surface concentration of the soft segments. Another advantage is that unlike grafting, where modification has to take place after device fabrication, these PSMs can be incorporated with the matrix material during device fabrication. The soft segments of these quaternized polyurethanes are produced via ring opening co-polymerization of oxetane monomers which possess either a trifluoroethoxy (3FOx) side chains or a quaternary ammonium side chain (C12). These soft segments are subsequently reacted with 4,4'-(methylene bis (p-cyclohexyl isocyanate)), HMDI and butanediol (BD) to form the PSM. It was initially intended to increase the concentration of quaternary ammonium charge by increasing PSM soft segment molecular weight. Unexpectedly, produced blends with surface microscale phase separation. This observation prompted further investigation of the effect of PSM soft segment molecular weight on phase separation in PSM-base polyurethane blends and the subsequent effects of this phase separation on the biocidal activity. Analysis of the surface morphology via tapping mode atomic force microscopy (TM-AFM) and scanning electron microscopy (SEM) revealed varying complexities in surface morphology as a function of the PSM soft

  20. Development of Microorganisms with Improved Transport and Biosurfactant Activity for Enhanced Oil Recovery

    Energy Technology Data Exchange (ETDEWEB)

    M.J. McInerney; K.E. Duncan; N. Youssef; T. Fincher; S.K. Maudgalya; M.J. Folmsbee; R. Knapp; Randy R. Simpson; N.Ravi; D. Nagle

    2005-08-15

    The project had three objectives: (1) to develop microbial strains with improved biosurfactant properties that use cost-effective nutrients, (2) to obtain biosurfactant strains with improved transport properties through sandstones, and (3) to determine the empirical relationship between surfactant concentration and interfacial tension and whether in situ reactions kinetics and biosurfactant concentration meets appropriate engineering design criteria. Here, we show that a lipopeptide biosurfactant produced by Bacillus mojavensis strain JF-2 mobilized substantial amounts of residual hydrocarbon from sand-packed columns and Berea sandstone cores when a viscosifying agent and a low molecular weight alcohol were present. The amount of residual hydrocarbon mobilized depended on the biosurfactant concentration. Tertiary oil recovery experiments showed that 10 to 40 mg/l of JF-2 biosurfactant in the presence of 0.1 mM 2,3-butanediol and 1 g/l of partially hydrolyzed polyacrylamide (PHPA) recovered 10-40% of residual oil from Berea sandstone cores. Even low biosurfactant concentrations (16 mg/l) mobilized substantial amounts of residual hydrocarbon (29%). The bio-surfactant lowered IFT by nearly 2 orders of magnitude compared to typical IFT values of 28-29 mN/m. Increasing the salinity increased the IFT with or without 2,3-butanediol present. The lowest interfacial tension observed was 0.1 mN/m. A mathematical model that relates oil recovery to biosurfactant concentration was modified to include the stepwise changes in IFT as biosurfactant concentrations changes. This model adequately predicted the experimentally observed changes in IFT as a function of biosurfactant concentration. Theses data show that lipopeptide biosurfactant systems may be effective in removing hydrocarbon contamination sources in soils and aquifers and for the recovery of entrapped oil from low production oil reservoirs. Diverse microorganisms were screened for biosurfactant production and anaerobic

  1. Structure-property relationships of flexible polyurethane foams

    Science.gov (United States)

    Aneja, Ashish

    segments to self-assemble and form lath-like percolated structures, resulting in solid plaques, even though the overall volume of the system was known to be dominated by the two terminal liquid-like polyether segments. In another aspect of this research, foams were investigated in which the ratios of the 2,4 and 2,6 TDI isomers were varied. The three commercially available TDI mixtures, i.e., 65:35 2,4/2,6 TDI, 80:20 2,4/2,6 TDI, and 100:0 2,4/2,6 TDI were used. These foams were shown to display marked differences in their cellular structure (SEM), urea aggregation behavior (TEM), and in the hydrogen bonding characteristics of the hard segments (FTIR). Finally, the nanoscale morphology of a series of 'model' segmented polyurethane elastomers, based on 1,4-butanediol extended piperazine based hard segments and poly(tetramethylene oxide) soft segments, was also investigated using AFM. The monodisperse hard segments of these 'model' polyurethanes contained precisely either one, two, three, or four repeating units. Not only did AFM image the microphase separated morphology of these polyurethanes, but it also revealed that the hard domains preferentially oriented with their long axis along the radial direction of the spherulites which they formed.

  2. Improving GHB withdrawal with baclofen: study protocol for a feasibility study for a randomised controlled trial.

    Science.gov (United States)

    Lingford-Hughes, Anne; Patel, Yash; Bowden-Jones, Owen; Crawford, Mike J; Dargan, Paul I; Gordon, Fabiana; Parrott, Steve; Weaver, Tim; Wood, David M

    2016-09-27

    GHB (gamma-hydroxybutyrate) and its pro-drugs GBL (gamma-butyrolactone) and 1,4-butanediol (1,4-BD) are central nervous system depressants whose street names include 'G' and 'liquid ecstasy'. They are used recreationally predominately for their stimulant and pro-sexual effects or for sedation to help with sleep and/or to 'come down' after using stimulant recreational drugs. Although overall population prevalence is low (0.1 %), in some groups such as men who have sex with men, GHB/GBL use may reach 20 %. GHB/GBL dependence may be associated with severe withdrawal with individuals presenting either acutely to emergency departments or to addiction services for support. Benzodiazepines are currently prescribed for GHB/GBL detoxification but do not prevent all complications, such as behavioural disinhibition, that may require hospitalisation or admission to a high dependency/intensive care unit. The GABAB receptor mediates most effects of GHB/GBL and the GABAB agonist, baclofen, has shown promise as an adjunct to benzodiazepines in reducing withdrawal severity when prescribed both during withdrawal and as a 2-day 'preload' prior to detoxification. The key aim of this feasibility study is provide information about recruitment and characteristics of the proposed outcome measure (symptom severity, complications including delirium and treatment escalation) to inform an application for a definitive randomised placebo controlled trial to determine the role of baclofen in the management of GHB/GBL withdrawal and whether starting baclofen 2 days earlier improves outcomes further. This is a prospective, randomised, double-blind, placebo-controlled feasibility study that will recruit participants (aged over 18 years) who are GHB/GBL-dependent and wish to undergo planned GHB/GBL detoxification or are at risk of acute withdrawal and are inpatients requiring unplanned withdrawal. We aim to recruit 88 participants: 28 unplanned inpatients and 60 planned outpatients. During

  3. The effect of hydroxyl functional groups and molar mass on the viscosity of non-crystalline organic and organic–water particles

    Directory of Open Access Journals (Sweden)

    J. W. Grayson

    2017-07-01

    Full Text Available The viscosities of three polyols and three saccharides, all in the non-crystalline state, have been studied. Two of the polyols (2-methyl-1,4-butanediol and 1,2,3-butanetriol were studied under dry conditions, the third (1,2,3,4-butanetetrol was studied as a function of relative humidity (RH, including under dry conditions, and the saccharides (glucose, raffinose, and maltohexaose were studied as a function of RH. The mean viscosities of the polyols under dry conditions range from 1.5  ×  10−1 to 3.7  ×  101 Pa s, with the highest viscosity being that of the tetrol. Using a combination of data determined experimentally here and literature data for alkanes, alcohols, and polyols with a C3 to C6 carbon backbone, we show (1 there is a near-linear relationship between log10 (viscosity and the number of hydroxyl groups in the molecule, (2 that on average the addition of one OH group increases the viscosity by a factor of approximately 22 to 45, (3 the sensitivity of viscosity to the addition of one OH group is not a strong function of the number of OH functional groups already present in the molecule up to three OH groups, and (4 higher sensitivities are observed when the molecule has more than three OH groups. Viscosities reported here for 1,2,3,4-butanetetrol particles are lower than previously reported measurements using aerosol optical tweezers, and additional studies are required to resolve these discrepancies. For saccharide particles at 30 % RH, viscosity increases by approximately 2–5 orders of magnitude as molar mass increases from 180 to 342 g mol−1, and at 80 % RH, viscosity increases by approximately 4–5 orders of magnitude as molar mass increases from 180 to 991 g mol−1. These results suggest oligomerization of highly oxidized compounds in atmospheric secondary organic aerosol (SOA could lead to large increases in viscosity, and may be at least partially responsible for the high

  4. Síntese e caracterização de poliuretanos segmentados contendo blocos de peso molecular controlado: parte 1 preparação e caracterização dos materiais Synthesis and characterization of segmented polyurethanes containing blocks of controlled molecular weight: 1. Materials preparation and characterization

    Directory of Open Access Journals (Sweden)

    C. L. Almeida

    1999-06-01

    molecular weight of 3800, and 1,6-hexamethylene diisocyanate. The molecular weight of these polymers varied acording to the NCO/OH ratio used in the synthesis, always greater than unity, providing -NCO end capped segments. The unreacted HDI was removed under vacuum (10-6-10-8mbar. The molecular weights of the soft segments, SS products, was determined by GPC analytical techniques. The hard segment was prepared from the reaction of the 1,6 hexamethylene diisocyanate and 1,4-butanediol, using a NCO/OH ratio equal to unity. These polymers were functionalized by the addition of an excess BDO after the reaction was completed, providing -OH terminated segments. The unreacted BDO was removed using a solvent. The molecular weights of the hard segments (HS products was determined by MALDI (matrix assisted laser desorption, analytical techniques. The coupling of the soft with the hard segment (SPU products was made in solution (DMF. The characterization of the SPU products was made by infrared, DSC, TGA, and mechanical analytical techniques. The SPU product characteristics were compared to those of a conventional polyurethane (PU, prepared by a prepolymer procedure.

  5. Evolution of the metabolic and regulatory networks associated with oxygen availability in two phytopathogenic enterobacteria

    Science.gov (United States)

    2012-01-01

    Background Dickeya dadantii and Pectobacterium atrosepticum are phytopathogenic enterobacteria capable of facultative anaerobic growth in a wide range of O2 concentrations found in plant and natural environments. The transcriptional response to O2 remains under-explored for these and other phytopathogenic enterobacteria although it has been well characterized for animal-associated genera including Escherichia coli and Salmonella enterica. Knowledge of the extent of conservation of the transcriptional response across orthologous genes in more distantly related species is useful to identify rates and patterns of regulon evolution. Evolutionary events such as loss and acquisition of genes by lateral transfer events along each evolutionary branch results in lineage-specific genes, some of which may have been subsequently incorporated into the O2-responsive stimulon. Here we present a comparison of transcriptional profiles measured using densely tiled oligonucleotide arrays for two phytopathogens, Dickeya dadantii 3937 and Pectobacterium atrosepticum SCRI1043, grown to mid-log phase in MOPS minimal medium (0.1% glucose) with and without O2. Results More than 7% of the genes of each phytopathogen are differentially expressed with greater than 3-fold changes under anaerobic conditions. In addition to anaerobic metabolism genes, the O2 responsive stimulon includes a variety of virulence and pathogenicity-genes. Few of these genes overlap with orthologous genes in the anaerobic stimulon of E. coli. We define these as the conserved core, in which the transcriptional pattern as well as genetic architecture are well preserved. This conserved core includes previously described anaerobic metabolic pathways such as fermentation. Other components of the anaerobic stimulon show variation in genetic content, genome architecture and regulation. Notably formate metabolism, nitrate/nitrite metabolism, and fermentative butanediol production, differ between E. coli and the phytopathogens

  6. Insights into CO2 Fixation Pathway of Clostridium autoethanogenum by Targeted Mutagenesis.

    Science.gov (United States)

    Liew, Fungmin; Henstra, Anne M; Winzer, Klaus; Köpke, Michael; Simpson, Sean D; Minton, Nigel P

    2016-05-24

    The future sustainable production of chemicals and fuels from nonpetrochemical resources and reduction of greenhouse gas emissions are two of the greatest societal challenges. Gas fermentation, which utilizes the ability of acetogenic bacteria such as Clostridium autoethanogenum to grow and convert CO2 and CO into low-carbon fuels and chemicals, could potentially provide solutions to both. Acetogens fix these single-carbon gases via the Wood-Ljungdahl pathway. Two enzyme activities are predicted to be essential to the pathway: carbon monoxide dehydrogenase (CODH), which catalyzes the reversible oxidation of CO to CO2, and acetyl coenzyme A (acetyl-CoA) synthase (ACS), which combines with CODH to form a CODH/ACS complex for acetyl-CoA fixation. Despite their pivotal role in carbon fixation, their functions have not been confirmed in vivo By genetically manipulating all three CODH isogenes (acsA, cooS1, and cooS2) of C. autoethanogenum, we highlighted the functional redundancies of CODH by demonstrating that cooS1 and cooS2 are dispensable for autotrophy. Unexpectedly, the cooS1 inactivation strain showed a significantly reduced lag phase and a higher growth rate than the wild type on H2 and CO2 During heterotrophic growth on fructose, the acsA inactivation strain exhibited 61% reduced biomass and the abolishment of acetate production (a hallmark of acetogens), in favor of ethanol, lactate, and 2,3-butanediol production. A translational readthrough event was discovered in the uniquely truncated (compared to those of other acetogens) C. autoethanogenum acsA gene. Insights gained from studying the function of CODH enhance the overall understanding of autotrophy and can be used for optimization of biotechnological production of ethanol and other commodities via gas fermentation. Gas fermentation is an emerging technology that converts the greenhouse gases CO2 and CO in industrial waste gases and gasified biomass into fuels and chemical commodities. Acetogenic bacteria

  7. Chemical incorporation of polyhedral oligomeric silsesquioxane into thermoset matrices

    Science.gov (United States)

    Cho, Hosouk

    A new class of organic-inorganic hybrid nanocomposites containing well-defined polyhedral oligomeric silsesquioxane (POSS) monomers, which have been copolymerized with organic monomers, were synthesized. Poly(isobutyl methacrylate-co-butanediol dimethacrylate-co-3-methacrylylpropyl-heptaisobutyl(T 8)polyhedral oligomeric silsesquioxane) (P(iBMA-co-BDMA-co-MA-POSS)) nanocomposites with different crosslink densities (BDMA loadings of 1, 3 and 5 wt%) and different MA-POSS percentages (5, 10, 15, 20 and 30 wt%) have been synthesized by radical-initiated terpolymerization. Linear P(iBMA-co-MA-POSS) copolymers were also prepared. Viscoelastic properties and morphologies were studied by DMTA (dynamic mechanical thermal analysis) and TEM (transmission electron microscopy). Two types of inorganic-organic hybrid polyhedral oligomeric silsesquioxane (POSS)/vinyl ester (VE) nanocomposites were synthesized. The first type contained a mixture of T8, T10 and T12 cages, each multifunctionalized with 3-methacrylylpropyl groups. The second type contained octa(3-methacrylylpropyldimethylsiloxyl)(T8)POSS. VE/POSS samples with weight ratios of 99/1, 97/3, 95/5, 90/10, 85/15 and 80/20 were prepared of each type. The nanocomposites were characterized by DMTA, TEM, scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (X-EDS), swelling, extraction and FT-IR. Three classes of inorganic-organic hybrid phenolic resin/polyhedral oligomeric silsesquioxane (POSS) nanocomposites were also synthesized via condensation polymerization. The POSS macromers employed included multifunctional dichloromethylsilylethylheptaisobutyl(T 8)POSS, trisilanolheptaphenyl-POSS, and poly(phenylsilsesquioxane) uncured POSS. A nonfunctional octaisobutyl(T8)POSS was blended into the uncured phenolic resin followed by curing under the same conditions as those used for the other three nanocomposites classes. Phenolic/POSS samples with weight ratios of 99/1, 97/3, 95/5 and 90/10 were prepared of each

  8. DEVELOPMENT OF MICROORGANISMS WITH IMPROVED TRANSPORT AND BIOSURFACTANT ACTIVITY FOR ENHANCED OIL RECOVERY

    Energy Technology Data Exchange (ETDEWEB)

    M.J. McInerney; N. Youssef; T. Fincher; S.K. Maudgalya; M.J. Folmsbee; R. Knapp; D. Nagle

    2004-05-31

    .1 mM 2,3-butanediol and 1 g/l of partially hydrolyzed polyacrylamide (PHPA) recovered 10-40% of residual oil from Berea sandstone cores. When PHPA was used alone, about 10% of the residual oil was recovered. Interfacial tension (IFT) decreased in a stepwise manner as biosurfactant concentration increased with marked reductions in IFT occurring at biosurfactant concentrations of 10 and 40 mg/l. When the biosurfactant concentration was greater than 10 mg/l, residual oil recovery linearly increased with biosurfactant concentration. A mathematical model that relates oil recovery to biosurfactant concentration was modified to include the stepwise changes in IFT as biosurfactant concentrations changes. This model adequately predicted the experimentally observed changes in IFT as a function of biosurfactant concentration. Our work shows that (1) diverse microorganisms produce biosurfactants, (2) nutrient manipulation may provide a mechanism to increase biosurfactant activity, (3) biosurfactant concentrations in excess of the critical micelle concentration recover substantial amounts of residual oil, and (4) equations that describe the effect of the biosurfactant on IFT adequately predict residual oil recovery in sandstone cores.

  9. Evolution of the metabolic and regulatory networks associated with oxygen availability in two phytopathogenic enterobacteria

    Directory of Open Access Journals (Sweden)

    Babujee Lavanya

    2012-03-01

    Full Text Available Abstract Background Dickeya dadantii and Pectobacterium atrosepticum are phytopathogenic enterobacteria capable of facultative anaerobic growth in a wide range of O2 concentrations found in plant and natural environments. The transcriptional response to O2 remains under-explored for these and other phytopathogenic enterobacteria although it has been well characterized for animal-associated genera including Escherichia coli and Salmonella enterica. Knowledge of the extent of conservation of the transcriptional response across orthologous genes in more distantly related species is useful to identify rates and patterns of regulon evolution. Evolutionary events such as loss and acquisition of genes by lateral transfer events along each evolutionary branch results in lineage-specific genes, some of which may have been subsequently incorporated into the O2-responsive stimulon. Here we present a comparison of transcriptional profiles measured using densely tiled oligonucleotide arrays for two phytopathogens, Dickeya dadantii 3937 and Pectobacterium atrosepticum SCRI1043, grown to mid-log phase in MOPS minimal medium (0.1% glucose with and without O2. Results More than 7% of the genes of each phytopathogen are differentially expressed with greater than 3-fold changes under anaerobic conditions. In addition to anaerobic metabolism genes, the O2 responsive stimulon includes a variety of virulence and pathogenicity-genes. Few of these genes overlap with orthologous genes in the anaerobic stimulon of E. coli. We define these as the conserved core, in which the transcriptional pattern as well as genetic architecture are well preserved. This conserved core includes previously described anaerobic metabolic pathways such as fermentation. Other components of the anaerobic stimulon show variation in genetic content, genome architecture and regulation. Notably formate metabolism, nitrate/nitrite metabolism, and fermentative butanediol production, differ between E

  10. Methods for measurement of reactive metabolites as a basis for cancer risk assessment: Application to 1,3-butadiene and isoprene

    Energy Technology Data Exchange (ETDEWEB)

    Fred, Charlotta [Stockholm Univ. (Sweden). Dept. of Environmental Chemistry

    2005-02-01

    1,3-Butadiene is a general air pollutant associated with combustion of organic matter and is also an extensively used monomer in polymer production. The cancer risk estimation of 1,3-butadiene is encumbered with large uncertainties. Extrapolation from tumour frequencies in long-term animal tests has led to a relatively high figure for the risk associated with 1,3-butadiene exposure. This is mainly based on observations of very high tumour incidences in butadiene-exposed mice, which in this respect are about 100 times more sensitive than rats. It has been hypothesized that a high cancer risk from 1,3-butadiene could be associated with its metabolism to the bifunctional 1,2:3,4-diepoxybutane (DEB) which, in comparison with monofunctional epoxides, 1,2-epoxy-3-butene (EB) and 1,2-epoxy-3,4-butanediol (EBdiol), is a highly effective mutagen, i.e. cancer initiator. Measurement of in vivo doses of DEB is therefore essential for the risk assessment of 1,3-butadiene. Reaction products with hemoglobin offer a possibility of measuring reactive metabolites in vivo. Hemoglobin adducts from EBdiol have in this study been measured with available methods, which are, however, not applicable to the bifunctional DEB, and method development was therefore needed. This work presents a procedure for measurement of a specific, ring-closed adduct, Pyr-Val, formed from the reaction of DEB with N-terminal valines in hemoglobin. It is based on LC-ESI-MS/MS analysis of the Pyr-modified N-terminal peptides enriched after trypsin digestion of globin. Mouse and rat could be compared regarding the metabolism of EB, DEB and EBdiol. From the data it was concluded that, in 1,3-butadiene exposure, about 60 times higher levels of DEB are formed in mice compared to rats. Estimates of in vivo doses in published cancer tests showed that carcinogenesis in mice is mainly due to DEB, whereas in rat, and possibly man, the monofunctional EBdiol is the predominant causative factor. Preliminarily, the cancer

  11. Combustion characteristics of SMX and SMX based propellants

    Science.gov (United States)

    Reese, David A.

    This work investigates the combustion of the new solid nitrate ester 2,3-hydroxymethyl-2,3-dinitro-1,4-butanediol tetranitrate (SMX, C6H 8N6O16). SMX was synthesized for the first time in 2008. It has a melting point of 85 °C and oxygen balance of 0% to CO 2, allowing it to be used as an energetic additive or oxidizer in solid propellants. In addition to its neat combustion characteristics, this work also explores the use of SMX as a potential replacement for nitroglycerin (NG) in double base gun propellants and as a replacement for ammonium perchlorate in composite rocket propellants. The physical properties, sensitivity characteristics, and combustion behaviors of neat SMX were investigated. Its combustion is stable at pressures of up to at least 27.5 MPa (n = 0.81). The observed flame structure is nearly identical to that of other double base propellant ingredients, with a primary flame attached at the surface, a thick isothermal dark zone, and a luminous secondary flame wherein final recombination reactions occur. As a result, the burning rate and primary flame structure can be modeled using existing one-dimensional steady state techniques. A zero gas-phase activation energy approximation results in a good fit between modeled and observed behavior. Additionally, SMX was considered as a replacement for nitroglycerin in a double base propellant. Thermochemical calculations indicate improved performance when compared with the common double base propellant JA2 at SMX loadings above 40 wt-%. Also, since SMX is a room temperature solid, migration may be avoided. Like other nitrate esters, SMX is susceptible to decomposition over long-term storage due to the presence of excess acid in the crystals; the addition of stabilizers (e.g., derivatives of urea) during synthesis should be sufficient to prevent this. the addition of Both unplasticized and plasticized propellants were formulated. Thermal analysis of unplasticized propellant showed a distinct melt