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Zou Z, Kaothien-Nakayama P, Ogawa-Iwamura J, Nakayama H. Metabolic engineering of high-salinity-induced biosynthesis of γ-aminobutyric acid improves salt-stress tolerance in a glutamic acid-overproducing mutant of an ectoine-deficient Halomonas elongata. Appl Environ Microbiol 2024; 90:e0190523. [PMID: 38112419 PMCID: PMC10807429 DOI: 10.1128/aem.01905-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 11/08/2023] [Indexed: 12/21/2023] Open
Abstract
A moderately halophilic eubacterium, Halomonas elongata, has been used as cell factory to produce fine chemical 1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid (ectoine), which functions as a major osmolyte protecting the cells from high-salinity stress. To explore the possibility of using H. elongata to biosynthesize other valuable osmolytes, an ectoine-deficient salt-sensitive H. elongata deletion mutant strain KA1 (ΔectABC), which only grows well in minimal medium containing up to 3% NaCl, was subjected to an adaptive mutagenesis screening in search of mutants with restored salt tolerance. Consequently, we obtained a mutant, which tolerates 6% NaCl in minimal medium by overproducing L-glutamic acid (Glu). However, this Glu-overproducing (GOP) strain has a lower tolerance level than the wild-type H. elongata, possibly because the acidity of Glu interferes with the pH homeostasis of the cell and hinders its own cellular accumulation. Enzymatic decarboxylation of Glu to γ-aminobutyric acid (GABA) by a Glu decarboxylase (GAD) could restore cellular pH homeostasis; therefore, we introduced an engineered salt-inducible HopgadBmut gene, which encodes a wide pH-range GAD mutant, into the genome of the H. elongata GOP strain. We found that the resulting H. elongata GOP-Gad strain exhibits higher salt tolerance than the GOP strain by accumulating high concentration of GABA as an osmolyte in the cell (176.94 µmol/g cell dry weight in minimal medium containing 7% NaCl). With H. elongata OUT30018 genetic background, H. elongata GOP-Gad strain can utilize biomass-derived carbon and nitrogen compounds as its sole carbon and nitrogen sources, making it a good candidate for the development of GABA-producing cell factories.IMPORTANCEWhile the wild-type moderately halophilic H. elongata can synthesize ectoine as a high-value osmolyte via the aspartic acid metabolic pathway, a mutant H. elongata GOP strain identified in this work opens doors for the biosynthesis of alternative valuable osmolytes via glutamic acid metabolic pathway. Further metabolic engineering to install a GAD system into the H. elongata GOP strain successfully created a H. elongata GOP-Gad strain, which acquired higher tolerance to salt stress by accumulating GABA as a major osmolyte. With the ability to assimilate biomass-derived carbon and nitrogen sources and thrive in high-salinity environment, the H. elongata GOP-Gad strain can be used in the development of sustainable GABA-producing cell factories.
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Affiliation(s)
- Ziyan Zou
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan
| | - Pulla Kaothien-Nakayama
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan
| | - Junpei Ogawa-Iwamura
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan
| | - Hideki Nakayama
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan
- Institute of Integrated Science and Technology, Nagasaki University, Nagasaki, Japan
- Organization for Marine Science and Technology, Nagasaki University, Nagasaki, Japan
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Li H, Pei J, Wei C, Lin Z, Pan H, Pan Z, Guo X, Yu Z. Sodium-Ion-Free Fermentative Production of GABA with Levilactobacillus brevis CD0817. Metabolites 2023; 13:metabo13050608. [PMID: 37233649 DOI: 10.3390/metabo13050608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 04/21/2023] [Accepted: 04/27/2023] [Indexed: 05/27/2023] Open
Abstract
Gamma-aminobutyric acid (GABA) has positive effects on many physiological processes. Lactic acid bacterial production of GABA is a future trend. This study aimed to produce a sodium-ion-free GABA fermentation process for Levilactobacillus brevis CD0817. In this fermentation, both the seed and fermentation media used L-glutamic acid instead of monosodium L-glutamate as the substrate. We optimized the key factors influencing GABA formation, adopting Erlenmeyer flask fermentation. The optimized values of the key factors of glucose, yeast extract, Tween 80, manganese ion, and fermentation temperature were 10 g/L, 35 g/L, 1.5 g/L, 0.2 mM, and 30 °C, respectively. Based on the optimized data, a sodium-ion-free GABA fermentation process was developed using a 10-L fermenter. During the fermentation, L-glutamic acid powder was continuously dissolved to supply substrate and to provide the acidic environment essential for GABA synthesis. The current bioprocess accumulated GABA at up to 331 ± 8.3 g/L after 48 h. The productivity of GABA was 6.9 g/L/h and the molar conversion rate of the substrate was 98.1%. These findings demonstrate that the proposed method is promising in the fermentative preparation of GABA by lactic acid bacteria.
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Affiliation(s)
- Haixing Li
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China
- Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
| | - Jinfeng Pei
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China
- Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
| | - Cheng Wei
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China
- Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
| | - Zhiyu Lin
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China
- Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
- School of Chemistry and Chemical Engineering, Nanchang University, Nanchang 330031, China
| | - Hao Pan
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China
- Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
- School of Chemistry and Chemical Engineering, Nanchang University, Nanchang 330031, China
| | - Zhenkang Pan
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China
- Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
| | - Xinyue Guo
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China
- Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
| | - Zhou Yu
- Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China
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Bartkiene E, Tolpeznikaite E, Klupsaite D, Starkute V, Bartkevics V, Skrastina A, Pavlenko R, Mockus E, Lele V, Batkeviciute G, Budrikyte A, Janulyte R, Jomantaite I, Kybartaite A, Knystautaite K, Valionyte A, Ruibys R, Rocha JM. Bio-Converted Spirulina for Nutraceutical Chewing Candy Formulations Rich in L-Glutamic and Gamma-Aminobutyric Acids. Microorganisms 2023; 11:microorganisms11020441. [PMID: 36838408 PMCID: PMC9959499 DOI: 10.3390/microorganisms11020441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 02/12/2023] Open
Abstract
This study aimed at evaluating changes of microalgae Spirulina during its fermentation with Lactiplantibacillus plantarum No. 122 strain, and further at incorporating Spirulina bio-converted for nutraceuticals rich in L-glutamic (L-Glu) and gamma-aminobutyric acids (GABA) into sucrose-free chewing candy (gummy) preparations. Fermented Spirulina had higher b* (yellowness) coordinates than untreated (non-fermented), and fermentation duration (24 and 48 h) had a statistically significant effect on colour coordinates. The highest contents of L-glutamic and gamma-aminobutyric acids (4062 and 228.6 mg/kg, respectively) were found in 24 and 48 h-fermented Spirulina, respectively. Fermentation increased the content of saturated fatty acids and omega-3 in Spirulina, while monounsaturated fatty acids and omega-6 were reduced. The addition of fermented Spirulina (FSp) significantly affected hardness, decreased lightness and yellowness, and increased the greenness of chewing candies. All chewing candy samples (with xylitol) prepared with 3 and 5 g of FSp and 0.2 µL of Citrus paradise essential oil received the highest scores for overall acceptability, and the highest intensity (0.052) of emotion "happy" was elicited by the sample group containing xylitol, agar, ascorbic acid, 3 g of FSp, and 0.1 µL of Mentha spicata essential oil. As an outcome of this research, one may conclude that fermented Spirulina has significant potential as an innovative ingredient in the production of healthier sucrose-free nutraceutical chewing candies.
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Affiliation(s)
- Elena Bartkiene
- Institute of Animal Rearing Technologies, Faculty of Animal Sciences, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
- Department of Food Safety and Quality, Faculty of Veterinary, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
- Correspondence: ; Tel.: +370-601-35837
| | - Ernesta Tolpeznikaite
- Institute of Animal Rearing Technologies, Faculty of Animal Sciences, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
| | - Dovile Klupsaite
- Institute of Animal Rearing Technologies, Faculty of Animal Sciences, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
| | - Vytaute Starkute
- Institute of Animal Rearing Technologies, Faculty of Animal Sciences, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
- Department of Food Safety and Quality, Faculty of Veterinary, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
| | - Vadims Bartkevics
- Institute of Food Safety, Animal Health and Environment “BIOR”, Zemgales Priekšpilsēta, LV-1076 Riga, Latvia
| | - Anna Skrastina
- Institute of Food Safety, Animal Health and Environment “BIOR”, Zemgales Priekšpilsēta, LV-1076 Riga, Latvia
| | - Romans Pavlenko
- Institute of Food Safety, Animal Health and Environment “BIOR”, Zemgales Priekšpilsēta, LV-1076 Riga, Latvia
| | - Ernestas Mockus
- Institute of Animal Rearing Technologies, Faculty of Animal Sciences, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
| | - Vita Lele
- Institute of Animal Rearing Technologies, Faculty of Animal Sciences, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
- Department of Food Safety and Quality, Faculty of Veterinary, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
| | - Gabija Batkeviciute
- Institute of Animal Rearing Technologies, Faculty of Animal Sciences, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
| | - Ausrine Budrikyte
- Institute of Animal Rearing Technologies, Faculty of Animal Sciences, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
| | - Rusne Janulyte
- Institute of Animal Rearing Technologies, Faculty of Animal Sciences, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
| | - Ieva Jomantaite
- Institute of Animal Rearing Technologies, Faculty of Animal Sciences, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
| | - Auguste Kybartaite
- Institute of Animal Rearing Technologies, Faculty of Animal Sciences, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
| | - Karolina Knystautaite
- Institute of Animal Rearing Technologies, Faculty of Animal Sciences, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
| | - Aiste Valionyte
- Institute of Animal Rearing Technologies, Faculty of Animal Sciences, Lithuanian University of Health Sciences, 44307 Kaunas, Lithuania
| | - Romas Ruibys
- Institute of Agricultural and Food Sciences, Agriculture Academy, Vytautas Magnus University, 44307 Kaunas, Lithuania
| | - João Miguel Rocha
- LEPABE-Laboratory for Process Engineering, Environment, Biotechnology and Energy, Department of Chemical Engineering (DEQ), Faculty of Engineering, University of Porto (FEUP), Rua Roberto Frias, s/n, 4200-465 Porto, Portugal
- ALiCE—Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
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Tolpeznikaite E, Bartkevics V, Skrastina A, Pavlenko R, Ruzauskas M, Starkute V, Zokaityte E, Klupsaite D, Ruibys R, Rocha JM, Bartkiene E. Submerged and Solid-State Fermentation of Spirulina with Lactic Acid Bacteria Strains: Antimicrobial Properties and the Formation of Bioactive Compounds of Protein Origin. Biology (Basel) 2023; 12. [PMID: 36829524 DOI: 10.3390/biology12020248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/27/2023] [Accepted: 01/31/2023] [Indexed: 02/09/2023]
Abstract
The aim of this study was to investigate the changes in bioactive compounds (L-glutamic acid (L-Glu), gamma-aminobutyric acid (GABA) and biogenic amines (BAs)) during the submerged (SMF) and solid-state (SSF) fermentation of Spirulina with lactobacilli strains (Lacticaseibacillus paracasei No. 244; Levilactobacillus brevis No. 173; Leuconostoc mesenteroides No. 225; Liquorilactobacillus uvarum No. 245). The antimicrobial properties of the untreated and fermented Spirulina against a variety of pathogenic and opportunistic strains were tested. The highest concentrations of L-Glu (3841 mg/kg) and GABA (2396 mg/kg) were found after 48 h of SSF with No. 173 and No. 244 strains, respectively. The LAB strain used for biotreatment and the process conditions, as well as the interaction of these factors, had statistically significant effects on the GABA concentration in Spirulina (p ≤ 0.001, p = 0.019 and p = 0.011, respectively). In all cases, the SSF of Spirulina had a higher total BA content than SMF. Most of the fermented Spirulina showed exceptional antimicrobial activity against Staphylococcus aureus but not against the other pathogenic bacteria. The ratios of BA/GABA and BA/L-Glu ranged from 0.5 to 62 and from 0.31 to 10.7, respectively. The GABA content was correlated with putrescine, cadaverine, histamine, tyramine, spermidine and spermine contents. The L-glutamic acid concentration showed positive moderate correlations with tryptamine, putrescine, spermidine and spermine. To summarize, while high concentrations of desirable compounds are formed during fermentation, the formation of non-desirable compounds (BAs) must also be considered due to the similar mechanism of their synthesis as well as the possibility of obtaining high concentrations in the end products.
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Takabait F, Martínez-Martínez S, Mahtout L, Graba Z, Sánchez-Soto PJ, Pérez-Villarejo L. Effect of L-Glutamic Acid on the Composition and Morphology of Nanostructured Calcium Phosphate as Biomaterial. Materials (Basel) 2023; 16:1262. [PMID: 36770268 PMCID: PMC9920287 DOI: 10.3390/ma16031262] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/26/2023] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
Calcium phosphate (CaP) with several chemical compositions and morphologies was prepared by precipitation using aqueous solutions of L-Glutamic acid (H2G) and calcium hydroxide, both mixed together with an aqueous solution (0.15 M) of phosphoric acid. Plate-shaped dicalcium phosphate dihydrate (brushite) particles were obtained and identified at a lower concentration of the solution of the reactants. The Ca/P ratio deduced by EDS was ~1, as expected. The nanoscale dimension of carbonate apatite and amorphous calcium phosphate, with variable Ca/P ratios, were revealed by X-ray diffraction (XRD) and scanning electron microscopy and energy dispersive X-ray spectroscopy analysis (SEM-EDS). They were characterized in medium and high concentrations of calcium hydroxide (0.15 M and 0.20 M). The equilibria involved in all the reactions in aqueous solution were determined. The thermodynamic calculations showed a decrease in the amount of chelate complexes with an increase in pH, being the opposite of [CaPO4-] and [CaHG+]. This fluctuation showed an evident influence on the morphology and polymorphism of CaP particles obtained under the present experimental conditions, with potential use as a biomaterial.
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Affiliation(s)
- Fatah Takabait
- Laboratoire de Technologie des Matériaux et de Génie des Procédés (LTMGP), Faculté des Sciences Exactes, Université A. Mira-Béjaïa, Terga Ouzemmour, Béjaïa 06000, Algeria
| | - Sergio Martínez-Martínez
- Department of Chemical, Environmental and Materials Engineering, Higher Polytechnic School of Linares, University of Jaén, Campus Científico y Tecnológico, Cinturón Sur s/n, 23700 Linares, Spain
- Institute of Materials Science of Sevilla (ICMS), Joint Center of the Spanish National Research Council (CSIC), University of Sevilla, Isla de la Cartuja, 41092 Seville, Spain
| | - Laila Mahtout
- Laboratoire de Technologie des Matériaux et de Génie des Procédés (LTMGP), Faculté des Sciences Exactes, Université A. Mira-Béjaïa, Terga Ouzemmour, Béjaïa 06000, Algeria
| | - Zahra Graba
- Laboratoire de Technologie des Matériaux et de Génie des Procédés (LTMGP), Faculté des Sciences Exactes, Université A. Mira-Béjaïa, Terga Ouzemmour, Béjaïa 06000, Algeria
| | - Pedro J. Sánchez-Soto
- Institute of Materials Science of Sevilla (ICMS), Joint Center of the Spanish National Research Council (CSIC), University of Sevilla, Isla de la Cartuja, 41092 Seville, Spain
| | - Luis Pérez-Villarejo
- Department of Chemical, Environmental and Materials Engineering, Higher Polytechnic School of Linares, University of Jaén, Campus Científico y Tecnológico, Cinturón Sur s/n, 23700 Linares, Spain
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Zhang H, Wang Z, Li Z, Wang K, Kong B, Chen Q. l-glycine and l-glutamic acid protect Pediococcus pentosaceus R1 against oxidative damage induced by hydrogen peroxide. Food Microbiol 2021; 101:103897. [PMID: 34579850 DOI: 10.1016/j.fm.2021.103897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 11/18/2022]
Abstract
The effects of l-glycine (Gly) and l-glutamic acid (Glu) on oxidative damage induced by hydrogen peroxide (H2O2) in Pediococcus pentosaceus R1 were investigated. Gly and Glu significantly reduce the production of intracellular reactive oxygen species and the levels of malondialdehyde and carbonylated proteins and concomitantly increase ATP levels in P. pentosaceus R1 under H2O2-induced stress (P < 0.05). Transmission electron microscopy and atomic force microscopy of bacteria under H2O2-induced stress revealed that Gly and Glu suppress bacterial membrane deformation and cell damage. Gly exhibited stronger ferrous ion-chelating ability, whereas Glu has higher radical scavenging activities and reducing power (P < 0.05). The abilities of Gly and Glu to inhibit lipid peroxidation are comparable. Gly and Glu significantly enhance the activities of superoxide dismutase and glutathione peroxidase, respectively, and increase the total antioxidant capacity of bacteria (P < 0.05). These findings indicate that Gly and Glu alleviate H2O2-induced oxidative stress via direct antioxidant effects and increase the activities of bacterial antioxidant enzyme.
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Affiliation(s)
- Huan Zhang
- College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China
| | - Zhi Wang
- College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China
| | - Zhiwei Li
- College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China
| | - Keda Wang
- College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China
| | - Baohua Kong
- College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China.
| | - Qian Chen
- College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang, 150030, China
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Kuntiyong P, Namborisut D, Phakdeeyothin K, Chatpreecha R, Thammapichai K. Enantiodivergent Synthesis of Benzoquinolizidinones from L-Glutamic Acid. Molecules 2021; 26:5866. [PMID: 34641410 DOI: 10.3390/molecules26195866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/20/2021] [Accepted: 09/23/2021] [Indexed: 11/17/2022] Open
Abstract
Benzoquinolizidinone systems were synthesized in both enantiomeric forms from L-glutamic acid. The key chiral arylethylglutarimide intermediate was synthesized from dibenzylamino-glutamate and homoveratrylamine. Aldol reaction of the glutarimide afforded a mixture of syn and anti-aldol adducts. Subsequent regioselective hydride reduction of the glutarimide carbonyl followed by N-acyliminium ion cyclization afforded a product with opposite absolute configurations at C3 and C11b. Cope elimination of the dibenzylamino group then converted the two diastereomers into enantiomers.
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Mihăilescu M, Negrea A, Ciopec M, Negrea P, Duțeanu N, Grozav I, Svera P, Vancea C, Bărbulescu A, Dumitriu CȘ. Full Factorial Design for Gold Recovery from Industrial Solutions. Toxics 2021; 9:toxics9050111. [PMID: 34065249 PMCID: PMC8160989 DOI: 10.3390/toxics9050111] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 05/12/2021] [Accepted: 05/18/2021] [Indexed: 11/16/2022]
Abstract
Gold is one of the precious metals with multiple uses, whose deposits are much smaller than the global production needs. Therefore, extracting maximum gold quantities from industrial diluted solutions is a must. Am-L-GA is a new material, obtained by an Amberlite XAD7-type commercial resin, functionalized through saturation with L-glutamic acid, whose adsorption capacity has been proved to be higher than those of other materials utilized for gold adsorption. In this context, this article presents the results of a factorial design experiment for optimizing the gold recovery from residual solutions resulting from the electronics industry using Am-L-GA. Firstly, the material was characterized using atomic force microscopy (AFM), to emphasize the material’s characteristics, essential for the adsorption quality. Then, the study showed that among the parameters taken into account in the analysis (pH, temperature, initial gold concentration, and contact time), the initial gold concentration in the solution plays a determinant role in the removal process and the contact time has a slightly positive effect, whereas the pH and temperature do not influence the adsorption capacity. The maximum adsorption capacity of 29.27 mg/L was obtained by optimizing the adsorption process, with the control factors having the following values: contact time ~106 min, initial Au(III) concentration of ~164 mg/L, pH = 4, and temperature of 25 °C. It is highlighted that the factorial design method is an excellent instrument to determine the effects of different factors influencing the adsorption process. The method can be applied for any adsorption process if it is necessary to reduce the number of experiments, to diminish the resources or time consumption, or for expanding the investigation domain above the experimental limits.
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Affiliation(s)
- Maria Mihăilescu
- Research Institute for Renewable Energies, Politehnica University Timişoara, 2, P-ța Victoriei, 300006 Timişoara, Romania;
| | - Adina Negrea
- Faculty of Industrial Chemistry and Environmental Enginering, Politehnica University Timişoara, 2, P-ța Victoriei, 300006 Timişoara, Romania; (A.N.); (M.C.); (P.N.); (N.D.); (I.G.); (C.V.)
| | - Mihaela Ciopec
- Faculty of Industrial Chemistry and Environmental Enginering, Politehnica University Timişoara, 2, P-ța Victoriei, 300006 Timişoara, Romania; (A.N.); (M.C.); (P.N.); (N.D.); (I.G.); (C.V.)
| | - Petru Negrea
- Faculty of Industrial Chemistry and Environmental Enginering, Politehnica University Timişoara, 2, P-ța Victoriei, 300006 Timişoara, Romania; (A.N.); (M.C.); (P.N.); (N.D.); (I.G.); (C.V.)
| | - Narcis Duțeanu
- Faculty of Industrial Chemistry and Environmental Enginering, Politehnica University Timişoara, 2, P-ța Victoriei, 300006 Timişoara, Romania; (A.N.); (M.C.); (P.N.); (N.D.); (I.G.); (C.V.)
| | - Ion Grozav
- Faculty of Industrial Chemistry and Environmental Enginering, Politehnica University Timişoara, 2, P-ța Victoriei, 300006 Timişoara, Romania; (A.N.); (M.C.); (P.N.); (N.D.); (I.G.); (C.V.)
| | - Paula Svera
- National Institute for Research-Development for Electrochemistry and Condensate Matter, 114, Dr. A. Păunescu Podeanu Str., 300224 Timişoara, Romania;
| | - Cosmin Vancea
- Faculty of Industrial Chemistry and Environmental Enginering, Politehnica University Timişoara, 2, P-ța Victoriei, 300006 Timişoara, Romania; (A.N.); (M.C.); (P.N.); (N.D.); (I.G.); (C.V.)
| | - Alina Bărbulescu
- Department of Civil Engineering, Transilvania University of Brașov, 5 Turnului Str., 900152 Brașov, Romania
- Correspondence: (A.B.); (C.Ș.D.)
| | - Cristian Ștefan Dumitriu
- SC Utilnavorep SA, Constanța, 55, Aurel Vlaicu Bd, 90055 Constanța, Romania
- Correspondence: (A.B.); (C.Ș.D.)
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Nisar S, Pandit AH, Nadeem M, Pandit AH, Rizvi MMA, Rattan S. γ-Radiation induced L-glutamic acid grafted highly porous, pH-responsive chitosan hydrogel beads: A smart and biocompatible vehicle for controlled anti-cancer drug delivery. Int J Biol Macromol 2021; 182:37-50. [PMID: 33775765 DOI: 10.1016/j.ijbiomac.2021.03.134] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 03/10/2021] [Accepted: 03/23/2021] [Indexed: 01/22/2023]
Abstract
In the present work, highly porous, pH-responsive, and biocompatible chitosan-based hydrogel beads were prepared through gamma-irradiated graft copolymerization technique using L-glutamic acid as the monomer. The glutamic acid grafted chitosan (CH-g-GA) hydrogel beads, loaded with the anti-cancer drug (Doxorubicin, Dox), were exploited for their potential application as anti-cancer drug delivery system. The grafting conditions were optimized by varying irradiation dose (kGy) and monomer concentration. Further, the hydrogel beads were analysed using FTIR, XRD, SEM, TGA/DSC, Zeta potential studies, BET analysis and their strength was determined using rheological analysis. The swelling characteristics of the beads were studied at various simulated body pH (2.1, 5.8, and 7.4) to study their pH-responsive behaviour. The in-vitro drug release from the beads was thus evaluated at pH 5.8, 7.4 using UV-visible spectroscopy. The highest swelling ratio (426%) and drug release (81.33% in 144 h) was observed at the pH of 5.8. The MTT assay was performed on HEK-293 cell-line to check their cytocompatibilty and the cell proliferation of Dox-loaded beads was studied on MCF-7 cell-line. A significant cytotoxicity against the cancer-cells was observed which further established their promising use in the controlled delivery of anti-cancer agents for localized cancer therapy.
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Affiliation(s)
- Safiya Nisar
- Amity Institute of Applied Sciences, Amity University, Sector-125, Noida 201303, India
| | - Ashiq Hussain Pandit
- Materials Research Laboratory, Department of Chemistry, Jamia Millia Islamia, New Delhi 110025, India
| | - Masood Nadeem
- Genome Biology Lab, Department of Biosciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Altaf Hussain Pandit
- Department of Chemistry, University of Kashmir, Srinagar, Jammu and Kashmir 190006, India
| | - M Mushahid Alam Rizvi
- Genome Biology Lab, Department of Biosciences, Jamia Millia Islamia, New Delhi 110025, India
| | - Sunita Rattan
- Amity Institute of Applied Sciences, Amity University, Sector-125, Noida 201303, India.
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10
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Cao LL, Han Y, Wang Y, Pei L, Yue Z, Qin L, Liu B, Cui J, Jia M, Wang H. Metabolic Profiling Identified a Novel Biomarker Panel for Metabolic Syndrome-Positive Hepatocellular Cancer. Front Endocrinol (Lausanne) 2021; 12:816748. [PMID: 35154012 PMCID: PMC8826723 DOI: 10.3389/fendo.2021.816748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 12/14/2021] [Indexed: 12/24/2022] Open
Abstract
Metabolic syndrome (MetS) is an independent risk factor for hepatocellular cancer (HCC). Currently, there is no highly sensitive and specific biomarkers for HCC surveillance in MetS population. Metabolomics has been reported as a powerful technology for biomarker discovery. In the present study, we aimed to explore novel biomarkers with high sensitivity and specificity for MetS-positive [MetS(+)] HCC by metabolomic analysis. At first, many serum metabolites were found dysregulated in MetS(+) HCC individuals. Validation of the dysregulated metabolites by targeted metabolite analyses revealed that serum L-glutamic acid (L-glu), pipecolic acid (PA) and 7-methylguanine (7-mG) were increased in MetS(+) HCC compared to MetS group. Then a biomarker panel including L-glu, PA and alpha-fetoprotein (AFP) was identified as a novel biomarker for the diagnosis of MetS(+) HCC. Receiver operating characteristic (ROC) curve was drawn and the area under the ROC curve (AUC) was 0.87 for discriminating MetS(+) HCC from MetS group. The biomarker panel was capable of detecting small (AUC = 0.82) and early-stage (AUC = 0.78) tumors as well. Moreover, it exhibited great diagnostic performance (AUC = 0.93) for discriminating MetS(+) HCC from other MetS-associated cancers, including colorectal cancer and gastric cancer. Collectively, our study establishes a novel diagnostic tool for MetS(+) HCC.
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Affiliation(s)
- Lin-Lin Cao
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
- *Correspondence: Lin-Lin Cao,
| | - Yi Han
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Yuanxiao Wang
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Lin Pei
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Zhihong Yue
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Li Qin
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Boyu Liu
- Department of Pharmacy, Peking University People’s Hospital, Beijing, China
| | - Jingwen Cui
- SCIEX Analytical Instrument Trading Co., Shanghai, China
| | - Mei Jia
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
| | - Hui Wang
- Department of Clinical Laboratory, Peking University People’s Hospital, Beijing, China
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11
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Fang C, Tang W, Wu S, Wang J, Gao Z, Gong J. Ultrasound-assisted intensified crystallization of L-glutamic acid: Crystal nucleation and polymorph transformation. Ultrason Sonochem 2020; 68:105227. [PMID: 32615404 DOI: 10.1016/j.ultsonch.2020.105227] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 06/09/2020] [Accepted: 06/10/2020] [Indexed: 06/11/2023]
Abstract
In this paper, the crystallization of L-glutamic acid with application of ultrasound was explored in detail, including the process of nucleation, polymorphic control and polymorphic transformation. The induction time and metastable zone widths (MSZWs) were measured with and without ultrasound during the nucleation process. The induction time and MSZWs were decreased by ultrasound and the induction time was further decreased by higher ultrasonic power. The calculated nucleation parameters (such as interfacial energy, critical nucleus size and critical Gibbs energy) showed an obvious decrease in the presence of ultrasound, indicating that the nucleation was enhanced with application of ultrasound. By adjusting the ultrasonic power in the quench cooling process, the difference in nucleation temperatures would determine the distribution of polymorphs. In further, the polymorphic transformation was investigated quantitatively, and to the best of our knowledge, it was the first time to study the transformation kinetics with ultrasound using Avrami-Erofeev model. In the transformation process, the crystallization mechanism of the stable form was modified by ultrasound. The ultrasound eliminated the nucleation element in the rate-limiting step and facilitated the crystal growth of stable form. Thus, the ultrasound has a profound influence on L-glutamic acid crystallization.
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Affiliation(s)
- Chen Fang
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, China; The Co-Innovation Center of Chemistry and Chemical Engineering of Tianjin, Tianjin 300072, China
| | - Weiwei Tang
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, China; The Co-Innovation Center of Chemistry and Chemical Engineering of Tianjin, Tianjin 300072, China
| | - Songgu Wu
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, China; The Co-Innovation Center of Chemistry and Chemical Engineering of Tianjin, Tianjin 300072, China
| | - Jingkang Wang
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, China; The Co-Innovation Center of Chemistry and Chemical Engineering of Tianjin, Tianjin 300072, China
| | - Zhenguo Gao
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, China; The Co-Innovation Center of Chemistry and Chemical Engineering of Tianjin, Tianjin 300072, China.
| | - Junbo Gong
- School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, China; The Co-Innovation Center of Chemistry and Chemical Engineering of Tianjin, Tianjin 300072, China.
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12
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Sahab NR, Subroto E, Balia RL, Utama GL. γ-Aminobutyric acid found in fermented foods and beverages: current trends. Heliyon 2020; 6:e05526. [PMID: 33251370 PMCID: PMC7680766 DOI: 10.1016/j.heliyon.2020.e05526] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 09/13/2020] [Accepted: 11/12/2020] [Indexed: 01/13/2023] Open
Abstract
γ-aminobutyric acid (GABA) is synthesised by glutamic acid decarboxylase which catalyses the decarboxylation of L-glutamic acid. L-glutamic acid is formed by α-ketoglutarate in the TCA cycle by glutamic acid dehydrogenase (GDH). GABA is found in the human brain, plants, animals and microorganisms. GABA functions as an antidepressant, antihypertensive, antidiabetic and immune system enhancer and has a good effect on neural disease. As GABA have pharmaceutical properties, conditions for GABA production need to be established. Microbiological GABA production is more safe and eco-friendly rather than chemical methods. Moreover, it is easier to control conditions of production using microorganisms compared to production in plants and animals. GABA production in fermented foods and beverages has the potential to be optimised to increase the functional effect of fermented foods and beverages.
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Affiliation(s)
- Novia R.M. Sahab
- Magister of Agro-Industrial Technology, Faculty of Agro-Industrial Technology, Universitas Padjadjaran, Jl. Raya Bandung-Sumedang Km.21 Jatinangor 45363, Indonesia
| | - Edy Subroto
- Magister of Agro-Industrial Technology, Faculty of Agro-Industrial Technology, Universitas Padjadjaran, Jl. Raya Bandung-Sumedang Km.21 Jatinangor 45363, Indonesia
| | - Roostita L. Balia
- Faculty of Animal Husbandry, Universitas Padjadjaran, Jl. Raya Bandung-Sumedang Km.21 Jatinangor 45363, Indonesia
| | - Gemilang L. Utama
- Magister of Agro-Industrial Technology, Faculty of Agro-Industrial Technology, Universitas Padjadjaran, Jl. Raya Bandung-Sumedang Km.21 Jatinangor 45363, Indonesia
- Center for Environment and Sustainability Science, Universitas Padjadjaran, Jl. Sekeloa Selatan No. 1 Bandung 40134, Indonesia
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13
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Chang YH, Tseng CC, Chao CY, Chen CH, Lin SY, Du JK. Mg-Zn-Ca Alloys for Hemostasis Clips for Vessel Ligation: In Vitro and In Vivo Studies of Their Degradation and Response. Materials (Basel) 2020; 13:ma13133039. [PMID: 32646030 PMCID: PMC7372433 DOI: 10.3390/ma13133039] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 06/25/2020] [Accepted: 07/01/2020] [Indexed: 01/02/2023]
Abstract
To control the degradation rate of magnesium (Mg) alloys, chitosan (CHI) and L-glutamic acid (LGA) were used as coatings on Mg-Zn-Ca alloys via dip coating. In this study, either two or seven CHI/LGA layers were applied as a coating on Mg-2.8Zn-0.8Ca alloy (ZX31) and Mg-2.8Zn-0.8Ca hemostasis clips (ZX31 clips). The morphologies, compositions, and surface roughness of the specimens were characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, and surface measurement devices. The degradation rates and behavior of the specimens were evaluated by immersing them in simulated body fluids and by applying these ZX31 clips on rabbits’ uterine tubes for five weeks. The specimen with seven layers (ZX31(CHI/LGA)7) exhibited improved corrosion behavior when compared with ZX31 or ZX31(CHI/LGA)2, with a reduced degradation rate of the Mg alloy in a simulated body environment. In vivo experiments showed that ZX31 clips exhibited good biocompatibilities in each group but could not maintain the clamping function for five weeks. The weight loss of ZX31(CHI/LGA)7 was significantly lower than that of the other groups. Consequently, it was verified that CHI can be used as a protective layer on a magnesium alloy surface via in vitro and in vivo experiments.
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Affiliation(s)
- Yen-Hao Chang
- School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
| | - Chun Chieh Tseng
- Combination Medical Device Technology Division, Medical Devices and Opto-Electronics Equipment Department, Metal Industries Research & Development Centre, Lujhu Township, Kaohsiung 82151, Taiwan;
| | - Chih-Yeh Chao
- Department of Mechanical Engineering, National Pingtung University of Science and Technology, Pingtung 91201, Taiwan;
| | - Chung-Hwan Chen
- Orthopedic Research Center, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; (C.-H.C.); (S.-Y.L.)
- Department of Orthopedics, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Division of Adult Reconstruction Surgery, Department of Orthopedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Department of Orthopedics, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University, Kaohsiung 80145, Taiwan
- Regeneration Medicine and Cell Therapy Research Center, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Sung-Yen Lin
- Orthopedic Research Center, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; (C.-H.C.); (S.-Y.L.)
- Department of Orthopedics, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Division of Adult Reconstruction Surgery, Department of Orthopedics, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Department of Orthopedics, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University, Kaohsiung 80145, Taiwan
- Regeneration Medicine and Cell Therapy Research Center, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Je-Kang Du
- School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan;
- Department of Dentistry, Kaohsiung Medical University Hospital, Kaohsiung 80708, Taiwan
- Correspondence: ; Tel.: +886-7-3121101
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14
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Sikri G, Sawhney RS. First principle approach to elucidate transport properties through L-glutamic acid-based molecular devices using symmetrical electrodes. J Mol Model 2020; 26:74. [PMID: 32146585 DOI: 10.1007/s00894-020-4323-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 02/23/2020] [Indexed: 10/24/2022]
Abstract
Protein-based electronics is one of the emerging technology in which inventive electronic devices are being adduced and developed based on the selective actions of specific proteins. The explicit actions can be predicted if the building blocks of proteins (i.e., amino acids) are studied decorously. We emphasize our work on electronic transport properties of L-glutamic acid (i.e., L-amino acid) stringed to gold, silver, and copper electrodes, respectively, to form three distinct devices. For our calculations, we employ NEGF-DFT approach using self-consistent function. Electronic coupling and tunneling barriers between the molecule and the electrodes have been emphasized with an inception of delocalization of molecular orbitals within the device. We observe strong correlation between tunneling barrier and Mulliken charge transfer between molecule and electrodes. The asymmetrical carbon chain (-CH2) within the molecule exhibits negative differential resistance (NDR) and rectification ratio. The device using molecule with copper electrodes exhibits the highest peak to valley current ratio of 1.84. The rectification ratio of the device with gold, silver, and copper electrodes is 2.35, 2.25, and 15.62, respectively, at finite bias. These results yield fresh insight on the potential of L-glutamic acid like bio-molecule in the emerging field of proteotronics.
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15
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Min JH, Reddy LV, Dimitris C, Kim YM, Wee YJ. Optimized Production of Poly(γ-Glutamic acid) By Bacillus sp. FBL-2 through Response Surface Methodology Using Central Composite Design. J Microbiol Biotechnol 2019; 29:1061-1070. [PMID: 31280522 DOI: 10.4014/jmb.1904.04013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
In the present study, the optimization of poly(γ-glutamic acid) (γ-PGA) production by Bacillus sp. FBL-2 was studied using a statistical approach. One-factor-at-a-time method was used to investigate the effect of carbon sources and nitrogen sources on γ-PGA production and was utilized to select the most significant nutrients affecting the yield of γ-PGA. After identifying effective nutrients, response surface methodology with central composite design (CCD) was used to obtain a mathematical model to identify the optimum concentrations of the key nutrients (sucrose, L-glutamic acid, yeast extract, and citric acid) for improvement of γ-PGA production. The optimum amount of significant medium components appeared to be sucrose 51.73 g/l, L-glutamic acid 105.30 g/l, yeast extract 13.25 g/l, and citric acid 10.04 g/l. The optimized medium was validated experimentally, and γ-PGA production increased significantly from 3.59 g/l (0.33 g/l/h) to 44.04 g/l (3.67 g/l/h) when strain FBL-2 was cultivated under the optimal medium developed by the statistical approach, as compared to non-optimized medium.
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Affiliation(s)
- Ju-Hee Min
- Department of Food Science and Technology, Yeungnam University, Gyeongsan 38541, Republic of Korea
| | - Lebaka Veeranjaneya Reddy
- Department of Food Science and Technology, Yeungnam University, Gyeongsan 38541, Republic of Korea.,Department of Microbiology, Yogi Vemana University, Kadapa (A.P.) 516 003, India
| | - Charalampopoulos Dimitris
- Department of Food and Nutritional Sciences, University of Reading, Whiteknights, PO Box 226, Reading RG6 6AP, UK
| | - Young-Min Kim
- Department of Food Science and Technology, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Young-Jung Wee
- Department of Food Science and Technology, Yeungnam University, Gyeongsan 38541, Republic of Korea
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16
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Yang X, Ke C, Zhu J, Wang Y, Zeng W, Huang J. Enhanced productivity of gamma-amino butyric acid by cascade modifications of a whole-cell biocatalyst. Appl Microbiol Biotechnol 2018; 102:3623-33. [PMID: 29516142 DOI: 10.1007/s00253-018-8881-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
We previously developed a gamma-amino butyric acid (GABA)-producing strain of Escherichia coli, leading to production of 614.15 g/L GABA at 45 °C from L-glutamic acid (L-Glu) with a productivity of 40.94 g/L/h by three successive whole-cell conversion cycles. However, the increase in pH caused by the accumulation of GABA resulted in inactivation of the biocatalyst and consequently led to relatively lower productivity. In this study, by overcoming the major problem associated with the increase in pH during the production process, a more efficient biocatalyst was obtained through cascade modifications of the previously reported E. coli strain. First, we introduced four amino acid mutations to the codon-optimized GadB protein from Lactococcus lactis to shift its decarboxylation activity toward a neutral pH, resulting in 306.65 g/L of GABA with 99.14 mol% conversion yield and 69.8% increase in GABA productivity. Second, we promoted transportation of L-Glu and GABA by removing the genomic region encoding the C-plug of GadC (a glutamate/GABA antiporter) to allow its transport path to remain open at a neutral pH, which improved the GABA productivity by 16.8% with 99.3 mol% conversion of 3 M L-Glu. Third, we enhanced the expression of soluble GadB by introducing the GroESL molecular chaperones, leading to 20.2% improvement in GABA productivity, with 307.40 g/L of GABA and a 61.48 g/L/h productivity obtained in one cycle. Finally, we inhibited the degradation of GABA by inactivation of gadA and gadB from the E. coli genome, which resulted in almost no GABA degradation after 40 h. After the cascade system modifications, the engineered recombinant E. coli strain achieved a 44.04 g/L/h productivity with a 99.6 mol% conversion of 3 M L-Glu in a 5-L bioreactor, about twofold increase in productivity compared to the starting strain. This increase represents the highest GABA productivity by whole-cell bioconversion using L-Glu as a substrate in one cycle observed to date, even better than the productivity obtained from the three successive conversion cycles.
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17
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Ding G, Hou Y, Peng J, Shen Y, Jiang M, Bai G. On-line near-infrared spectroscopy optimizing and monitoring biotransformation process of γ-aminobutyric acid. J Pharm Anal 2016; 6:171-178. [PMID: 29403978 PMCID: PMC5762498 DOI: 10.1016/j.jpha.2016.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 01/14/2016] [Accepted: 02/04/2016] [Indexed: 11/23/2022] Open
Abstract
Near-infrared spectroscopy (NIRS) with its fast and nondestructive advantages can be qualified for the real-time quantitative analysis. This paper demonstrates that NIRS combined with partial least squares (PLS) regression can be used as a rapid analytical method to simultaneously quantify l-glutamic acid (l-Glu) and γ-aminobutyric acid (GABA) in a biotransformation process and to guide the optimization of production conditions when the merits of NIRS are combined with response surface methodology. The high performance liquid chromatography (HPLC) reference analysis was performed by the o-phthaldialdehyde pre-column derivatization. NIRS measurements of two batches of 141 samples were firstly analyzed by PLS with several spectral pre-processing methods. Compared with those of the HPLC reference analysis, the resulting determination coefficients (R2), root mean square error of prediction (RMSEP) and residual predictive deviation (RPD) of the external validation for the l-Glu concentration were 99.5%, 1.62 g/L, and 11.3, respectively. For the GABA concentration, R2, RMSEP, and RPD were 99.8%, 4.00 g/L, and 16.4, respectively. This NIRS model was then used to optimize the biotransformation process through a Box-Behnken experimental design. Under the optimal conditions without pH adjustment, 200 g/L l-Glu could be catalyzed by 7148 U/L glutamate decarboxylase (GAD) to GABA, reaching 99% conversion at the fifth hour. NIRS analysis provided timely information on the conversion from l-Glu to GABA. The results suggest that the NIRS model can not only be used for the routine profiling of enzymatic conversion, providing a simple and effective method of monitoring the biotransformation process of GABA, but also be considered to be an optimal tool to guide the optimization of production conditions.
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Affiliation(s)
| | - Yuanyuan Hou
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University; Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Tianjin 300071, China
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Hinrichsen S, Planer-Friedrich B. Cytotoxic activity of selenosulfate versus selenite in tumor cells depends on cell line and presence of amino acids. Environ Sci Pollut Res Int 2016; 23:8349-8357. [PMID: 26780055 DOI: 10.1007/s11356-015-5960-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 12/10/2015] [Indexed: 06/05/2023]
Abstract
Based on acute cytotoxicity studies, selenosulfate (SeSO3 (-)) has been suggested to possess a generally higher toxic activity in tumor cells than selenite. The reason for this difference in cytotoxic activity remained unclear. In the present study, cytotoxicity tests with human hepatoma (HepG2), malignant melanoma (A375), and urinary bladder carcinoma cells (T24) showed that the selenosulfate toxicity was very similar between all three tested cell lines (IC50 6.6-7.1 μM after 24 h). It was largely independent of exposure time and presence or absence of amino acids. What changed, however, was the toxicity of selenite, which was lower than that of selenosulfate only for HepG2 cells (IC50 > 15 μM), but similar to and higher than that of selenosulfate for A375 (IC50 4.7 μM) and T24 cells (IC50 3.5 μM), respectively. Addition of amino acids to T24 cell growth medium downregulated short-term selenite uptake (1.5 versus 12.9 ng Se/10(6) cells) and decreased its cytotoxicity (IC50 8.4 μM), rendering it less toxic than selenosulfate. The suggested mechanism is a stronger expression of the xc (-) transport system in the more sensitive T24 compared to HepG2 cells which creates a reductive extracellular microenvironment and facilitates selenite uptake by reduction. Selenosulfate is already reduced and so less affected. The cytotoxic activity of selenosulfate and selenite to tumor cells therefore depends on the sensitivity of each cell line, supplements like amino acids as well as the reductive state of the extracellular environment.
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Affiliation(s)
- Sinikka Hinrichsen
- Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BayCEER), University of Bayreuth, 95440, Bayreuth, Germany
| | - Britta Planer-Friedrich
- Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BayCEER), University of Bayreuth, 95440, Bayreuth, Germany.
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Göktürk I, Üzek R, Uzun L, Denizli A. Synthesis of a specific monolithic column with artificial recognition sites for L-glutamic acid via cryo-crosslinking of imprinted nanoparticles. Artif Cells Nanomed Biotechnol 2015; 44:1133-40. [PMID: 25749280 DOI: 10.3109/21691401.2015.1011806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In this study, a new molecular imprinting (MIP)-based monolithic cryogel column was prepared using chemically crosslinked molecularly imprinted nanoparticles, to achieve a simplified chromatographic separation (SPE) for a model compound, L-glutamic acid (L-Glu). Cryogelation through crosslinking of imprinted nanoparticles forms stable monolithic cryogel columns. This technique reduces the leakage of nanoparticles and increases the surface area, while protecting the structural features of the cryogel for stable and efficient recognition of the template molecule. A non-imprinted monolithic cryogel column (NIP) was also prepared, using non-imprinted nanoparticles produced without the addition of L-Glu during polymerization. The molecularly imprinted monolithic cryogel column (MIP) indicates apparent recognition selectivity and a good adsorption capacity compared to the NIP. Also, we have achieved a significant increase in the adsorption capacity, using the advantage of high surface area of the nanoparticles.
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Affiliation(s)
- Ilgım Göktürk
- a Nanomedicine and Nanotechnology Division, Hacettepe University , Ankara , Turkey.,b Department of Chemistry , Hacettepe University , Ankara , Turkey
| | - Recep Üzek
- b Department of Chemistry , Hacettepe University , Ankara , Turkey
| | - Lokman Uzun
- b Department of Chemistry , Hacettepe University , Ankara , Turkey
| | - Adil Denizli
- b Department of Chemistry , Hacettepe University , Ankara , Turkey
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20
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Sancheti JS, Shaikh MF, Khatwani PF, Kulkarni SR, Sathaye S. Development and Validation of a HPTLC Method for Simultaneous Estimation of L-Glutamic Acid and γ-Aminobutyric Acid in Mice Brain. Indian J Pharm Sci 2013; 75:716-21. [PMID: 24591747 PMCID: PMC3928736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 10/19/2013] [Accepted: 10/26/2013] [Indexed: 10/29/2022] Open
Abstract
A new robust, simple and economic high performance thin layer chromatographic method was developed for simultaneous estimation of L-glutamic acid and γ-amino butyric acid in brain homogenate. The high performance thin layer chromatographic separation of these amino acid was achieved using n-butanol:glacial acetic acid:water (22:3:5 v/v/v) as mobile phase and ninhydrin as a derivatising agent. Quantitation of the method was achieved by densitometric method at 550 nm over the concentration range of 10-100 ng/spot. This method showed good separation of amino acids in the brain homogenate with Rf value of L-glutamic acid and γ-amino butyric acid as 21.67±0.58 and 33.67±0.58, respectively. The limit of detection and limit of quantification for L-glutamic acid was found to be 10 and 20 ng and for γ-amino butyric acid it was 4 and 10 ng, respectively. The method was also validated in terms of accuracy, precision and repeatability. The developed method was found to be precise and accurate with good reproducibility and shows promising applicability for studying pathological status of disease and therapeutic significance of drug treatment.
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Affiliation(s)
- J. S. Sancheti
- Departments of Pharmaceutical Science and Technology, Insitute of Chemical Technology, N. P. Marg, Matunga, Mumbai-400 019, India
| | - M. F. Shaikh
- Department of Neuroscience, Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Sunway Campus, Petaling Jaya, Selangor 46150, Malaysia
| | - P. F. Khatwani
- Departments of Pharmacognosy and Phytochemistry, Bombay College of Pharmacy, Kalina, Santacruz (E), Mumbai-400 098, India
| | - Savita R. Kulkarni
- Departments of Pharmacognosy and Phytochemistry, Bombay College of Pharmacy, Kalina, Santacruz (E), Mumbai-400 098, India
| | - Sadhana Sathaye
- Departments of Pharmaceutical Science and Technology, Insitute of Chemical Technology, N. P. Marg, Matunga, Mumbai-400 019, India
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Abstract
We report the terahertzpulse spectra of L-glutamic acid. Thereare a number of well-resolved transitionsin the 1.75-2.5 THz (58-83 cm(-1))region. These are compared with publishedtheoretical data on intra andintermolecular transitions. We could notfind any correlation with the theoreticalvalues. However, it was noted that thetheoretical model did not include anycrystalline or hydrogen-bonding effects.
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Affiliation(s)
- P F Taday
- TeraView Ltd, 02/304 Cambridge Science Park, Milton Road, Cambridge, CB4 0WG UK
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