The Experts below are selected from a list of 210 Experts worldwide ranked by ideXlab platform
Jens Petter Andreassen - One of the best experts on this subject based on the ideXlab platform.
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Polycrystalline growth in precipitation of an aromatic amine derivative and L-Glutamic Acid
Journal of Crystal Growth, 2020Co-Authors: Ralf Beck, Didrik Malthe-sørenssen, Jens Petter AndreassenAbstract:Polycrystalline growth in precipitation of an aromatic amine derivative and L-Glutamic Acid
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Formation and ageing of L‐glutamic Acid spherulites
Crystal Research and Technology, 2010Co-Authors: Ralf Beck, Didrik Malthe-sørenssen, Jens Petter AndreassenAbstract:Polycrystalline spherulites of L-Glutamic Acid have been crystallized by pH-shift precipitation from stirred aqueous solutions. The time dependent behaviour of the spherulites has been studied during the crystallization process and batch filtration tests have been performed. It has been shown that the FBRM mean chord length of the investigated spherulites decreases in the course of time. The fact that the size reduction progresses faster at higher temperature and the solubility of resuspended polycrystalline particles decreasing with time, implies an ageing mechanism to be responsible for the observed changes in the particle size. It has been shown that the surface area decreases with time, ruling out particle breakage as a possible explanation for the decrease in particle size. XRD and Raman studies of L-Glutamic Acid, however, show only marginal differences in the crystalline structure of particles obtained from different time stages. The ageing may occur due to several different mechanisms like phase transformation and Ostwald ripening. L-Glutamic Acid spherulites after 3 h exhibit a 3-fold higher value for the cake resistance as compared to particles after 0.5 h. However, particles obtained after 22 h exhibit an 8-fold lower cake resistance as compared to the initially obtained spherulites, The increase in the cake resistance is attributed to the appearance of small plate-like crystals and a change in the interaction between the crystal surface and the solution. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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Formation and ageing of L-Glutamic Acid spherulites
Crystal Research and Technology, 2010Co-Authors: Ralf Beck, Didrik Malthe-Sørenssen, Jens Petter AndreassenAbstract:Polycrystalline spherulites of L-Glutamic Acid have been crystallized by pH-shift precipitation from stirred aqueous solutions. The time dependent behaviour of the spherulites has been studied during the crystallization process and batch filtration tests have been performed. It has been shown that the FBRM mean chord length of the investigated spherulites decreases in the course of time. The fact that the size reduction progresses faster at higher temperature and the solubility of resuspended polycrystalline particles decreasing with time, implies an ageing mechanism to be responsible for the observed changes in the particle size. It has been shown that the surface area decreases with time, ruling out particle breakage as a possible explanation for the decrease in particle size. XRD and Raman studies of L-Glutamic Acid, however, show only marginal differences in the crystalline structure of particles obtained from different time stages. The ageing may occur due to several different mechanisms like phase transformation and Ostwald ripening. L-Glutamic Acid spherulites after 3 h exhibit a 3-fold higher value for the cake resistance as compared to particles after 0.5 h. However, particles obtained after 22 h exhibit an 8-fold lower cake resistance as compared to the initially obtained spherulites, The increase in the cake resistance is attributed to the appearance of small plate-like crystals and a change in the interaction between the crystal surface and the solution. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Junqi Du - One of the best experts on this subject based on the ideXlab platform.
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temperature dependent solubility of α form l glutamic Acid in selected organic solvents measurements and thermodynamic modeling
Industrial & Engineering Chemistry Research, 2011Co-Authors: Bingwen Long, Jing Li, Yuhong Song, Junqi DuAbstract:In this study the solubility of α-form L-Glutamic Acid in the six organic solvents methanol, ethanol, 1-propanol, acetone, formic Acid, and dimethyl sulfoxide (DMSO) was measured by a static analytic method. The measurements were carried out over the temperature range 278–355 K at around 5 K intervals, and the equilibrium concentration was determined by the gravimetric method. The experimental results show that formic Acid has the highest solubility to α-form L-Glutamic Acid while the other solvents have the solubility order water, acetone, 1-propanol, ethanol, methanol, DMSO, and acetic Acid. The hypothetical enthalpy of fusion and melting temperature of L-Glutamic Acid are estimated. Several commonly used thermodynamic models, including the empirical van’t Hoff equation and the Wilson, NRTL, and UNIQUAC equations, were applied to correlate the experimental solubility data. The binary interaction parameters of the above models are found to have a linear dependency on temperature, and the coefficients wer...
B K Hodnett - One of the best experts on this subject based on the ideXlab platform.
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Effect of Amino Acid Additives on the Crystallization of L-Glutamic Acid
Crystal Growth & Design, 2005Co-Authors: C Cashell, David Corcoran, B K HodnettAbstract:The influence of a range of amino Acid additives on the crystallization of L-Glutamic Acid has been investigated. The presence of a bulky side chain (phenyl) in l-phenylalanine and l-tyrosine was identified as an essential feature in achieving stabilization of the α-polymorph at low additive concentrations. Minute quantities of these additives were incorporated into the α-L-Glutamic Acid product crystals when the additive/L-Glutamic molar ratio was 1:30 in solution; in this condition no β-form inclusions were observed inside the α-form crystals. At higher additive/L-Glutamic Acid molar ratios in solution (1:6), a significant amount of additive uptake was observed and changes in α-form morphology were noted under these conditions. A key feature was the disappearance of the {011} and {001} facets of α-L-Glutamic Acid and the emergence of the {111}and {110} facets. The overall hypothesis is that additives disrupt the developing β/α interface and this stabilizes the α-form.
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secondary nucleation of the β polymorph of l glutamic Acid on the surface of α form crystals
Chemical Communications, 2003Co-Authors: C Cashell, David Corcoran, B K HodnettAbstract:Evidence is presented for the secondary nucleation of β-L-Glutamic Acid on the surface of the α-polymorph, using a combination of Scanning Electron Microscopy and Raman spectroscopy.
Chen Ning - One of the best experts on this subject based on the ideXlab platform.
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Study on variable temperature control strategy of L-Glutamic Acid production
Tianjin Chemical Industry, 2020Co-Authors: Chen NingAbstract:In this paper,L-Glutamic Acid production by Brevibacterium flavum GDK-9 at various temperature was investigated to study the effect of temperature on L-Glutamic Acid fermentation.Different cultivation temperatures ranging from 30℃ to 36℃ were evaluated in shake flasks.The result indicated that 34℃ was the best for cell growth and the maximum L-Glutamic Acid production(86 g/L)was obtained.Based on the result,three temperature-shifted controlling manners were studied.The conclusion was as follows: 0-6h,culture temperature is 34℃,and it is increased 1℃ every 6h after 6h.In 5L jar fermentor,130 g/L L-Glutamic Acid was accumulated in 36h using this controlling manner,which was increased 27% compared with before.
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Optimization of oxygen supply of L-Glutamic Acid fermentation by Kla value
Tianjin Chemical Industry, 2020Co-Authors: Chen NingAbstract:The oxygen supply of L-Glutamic Acid fermentation was optimized by Kla value.The research indicated that when the Kla value was about 377 h-1,the oxygen supply was most suitable for the fermentation and 130g/L L-Glutamic Acid was accumulated.
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Effects of malate on metabolic flux transfer of L-Glutamic Acid fermentation
Chinese Journal of Bioprocess Engineering, 2020Co-Authors: Chen NingAbstract:In order to understand the regulating mechanism of L-Glutamic Acid metabolism,the metabolic flux transfer during the middle and late period with the addition of malate was studied with the linear programming with MATLAB software.When 2.0 g/L of malate was added to the fermentation medium,the metabolic flux of byproducts L-Ala and lactic Acid decreased by 22.1% and 16.5%.At the same time,the metabolic channeled to EMP and glyoxyl circle decreased by 2.26% and 9.09%.However,the metabolic flux channeled to HMP increased by 2.26%.The metabolic flux channeled to the L-Glutamic Acid synthesis pathway increased from 73.59% to 79.92%.The addition of the malate changed the metabolic flux distributions of the key nodes and strengthened the L-Glutamic Acid biosynthesis.
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Domestication of temperature-sensitive mutant and optimization of L-Glutamic Acid-producing conditions
China Brewing, 2020Co-Authors: Chen NingAbstract:Domestication of temperature-sensitive mutant was studied for the production of L-Glutamic Acid grown on fermentation medium with 80 g/L sugarcane molasses.Results showed that this method was efficient and could increase the yield of L-Glutamic Acid to 126 g/L and the conversion rate to 61.24%,based on the optimized fermentation conditions.
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Effects of Sodium Citrate on Metabolic Flux Transfer of L-Glutamic Acid Fermentation
Journal of Tianjin University of Science and Technology, 2020Co-Authors: Chen NingAbstract:In order to understand the regulate mechanism of L-Glutamic Acid metabolism,the metabolic flux transfer during the middle and late period of fermentation with the addition of sodium citrate was studied using MATLAB software with Brevibacterium flavum GDK-9 as the test strain.When 3.0 g/L sodium citrate was added to the fermentation medium,the formation of byproducts,such as L-ala and Lac,decreased by 18.7% and 27.4%,respectively.At the same time,the flux channeled to EMP and glyoxyl circle decreased by 0.88 and 2.12,respectively,however,the flux channeled to HMP increased by 0.88.The metabolic flux channeled to the L-Glutamic Acid synthesis pathway increased by 3.9%(from 73.59 to 76.47).All of these showed that the addition of sodium citrate could change the metabolic flux distributions of the key nodes and strengthen the L-Glutamic Acid biosynthesis.
Ralf Beck - One of the best experts on this subject based on the ideXlab platform.
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Polycrystalline growth in precipitation of an aromatic amine derivative and L-Glutamic Acid
Journal of Crystal Growth, 2020Co-Authors: Ralf Beck, Didrik Malthe-sørenssen, Jens Petter AndreassenAbstract:Polycrystalline growth in precipitation of an aromatic amine derivative and L-Glutamic Acid
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Formation and ageing of L‐glutamic Acid spherulites
Crystal Research and Technology, 2010Co-Authors: Ralf Beck, Didrik Malthe-sørenssen, Jens Petter AndreassenAbstract:Polycrystalline spherulites of L-Glutamic Acid have been crystallized by pH-shift precipitation from stirred aqueous solutions. The time dependent behaviour of the spherulites has been studied during the crystallization process and batch filtration tests have been performed. It has been shown that the FBRM mean chord length of the investigated spherulites decreases in the course of time. The fact that the size reduction progresses faster at higher temperature and the solubility of resuspended polycrystalline particles decreasing with time, implies an ageing mechanism to be responsible for the observed changes in the particle size. It has been shown that the surface area decreases with time, ruling out particle breakage as a possible explanation for the decrease in particle size. XRD and Raman studies of L-Glutamic Acid, however, show only marginal differences in the crystalline structure of particles obtained from different time stages. The ageing may occur due to several different mechanisms like phase transformation and Ostwald ripening. L-Glutamic Acid spherulites after 3 h exhibit a 3-fold higher value for the cake resistance as compared to particles after 0.5 h. However, particles obtained after 22 h exhibit an 8-fold lower cake resistance as compared to the initially obtained spherulites, The increase in the cake resistance is attributed to the appearance of small plate-like crystals and a change in the interaction between the crystal surface and the solution. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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Formation and ageing of L-Glutamic Acid spherulites
Crystal Research and Technology, 2010Co-Authors: Ralf Beck, Didrik Malthe-Sørenssen, Jens Petter AndreassenAbstract:Polycrystalline spherulites of L-Glutamic Acid have been crystallized by pH-shift precipitation from stirred aqueous solutions. The time dependent behaviour of the spherulites has been studied during the crystallization process and batch filtration tests have been performed. It has been shown that the FBRM mean chord length of the investigated spherulites decreases in the course of time. The fact that the size reduction progresses faster at higher temperature and the solubility of resuspended polycrystalline particles decreasing with time, implies an ageing mechanism to be responsible for the observed changes in the particle size. It has been shown that the surface area decreases with time, ruling out particle breakage as a possible explanation for the decrease in particle size. XRD and Raman studies of L-Glutamic Acid, however, show only marginal differences in the crystalline structure of particles obtained from different time stages. The ageing may occur due to several different mechanisms like phase transformation and Ostwald ripening. L-Glutamic Acid spherulites after 3 h exhibit a 3-fold higher value for the cake resistance as compared to particles after 0.5 h. However, particles obtained after 22 h exhibit an 8-fold lower cake resistance as compared to the initially obtained spherulites, The increase in the cake resistance is attributed to the appearance of small plate-like crystals and a change in the interaction between the crystal surface and the solution. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
