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Schrader M, Schrinner K, Polomsky L, Ivanov D, Kampen I, Schilde C, Krull R, Kwade A. Quantification and modeling of macroparticle-induced mechanical stress for varying shake flask cultivation conditions. Front Bioeng Biotechnol 2023; 11:1254136. [PMID: 37731767 PMCID: PMC10507416 DOI: 10.3389/fbioe.2023.1254136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 08/08/2023] [Indexed: 09/22/2023] Open
Abstract
In biotechnological processes, filamentous microorganisms are known for their broad product spectrum and complex cellular morphology. Product formation and cellular morphology are often closely linked, requiring a well-defined level of mechanical stress to achieve high product concentrations. Macroparticles were added to shake flask cultures of the filamentous actinomycete Lentzea aerocolonigenes to find these optimal cultivation conditions. However, there is currently no model concept for the dependence of the strength and frequency of the bead-induced stress on the process parameters. Therefore, shake flask simulations were performed for combinations of bead size, bead concentration, bead density and shaking frequency. Contact analysis showed that the highest shear stresses were caused by bead-bottom contacts. Based on this, a newly generated characteristic parameter, the stress area ratio (SAR), was defined, which relates the bead wall shear and normal stresses to the total shear area. Comparison of the SAR with previous cultivation results revealed an optimum pattern for product concentration and mean product-to-biomass related yield coefficient. Thus, this model is a suitable tool for future optimization, comparison and scaling up of shear-sensitive microorganism cultivation. Finally, the simulation results were validated using high-speed recordings of the bead motion on the bottom of the shake flask.
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Affiliation(s)
- Marcel Schrader
- Institute for Particle Technology, Technische Universität Braunschweig, Braunschweig, Germany
- Center of Pharmaceutical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
| | - Kathrin Schrinner
- Center of Pharmaceutical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
- Institute of Biochemical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
| | - Laura Polomsky
- Institute for Particle Technology, Technische Universität Braunschweig, Braunschweig, Germany
- Center of Pharmaceutical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
| | - Dimitri Ivanov
- Institute for Particle Technology, Technische Universität Braunschweig, Braunschweig, Germany
- Center of Pharmaceutical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
| | - Ingo Kampen
- Institute for Particle Technology, Technische Universität Braunschweig, Braunschweig, Germany
- Center of Pharmaceutical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
| | - Carsten Schilde
- Institute for Particle Technology, Technische Universität Braunschweig, Braunschweig, Germany
- Center of Pharmaceutical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
| | - Rainer Krull
- Center of Pharmaceutical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
- Institute of Biochemical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
| | - Arno Kwade
- Institute for Particle Technology, Technische Universität Braunschweig, Braunschweig, Germany
- Center of Pharmaceutical Engineering, Technische Universität Braunschweig, Braunschweig, Germany
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Silva TAFDA, Silva PEDACE, Nascimento TP, Costa RMPB, Converti A, Porto ALF, Bezerra RP. Cost-effective fibrinolytic enzyme production by microalga Dunaliella tertiolecta using medium supplemented with corn steep liquor. AN ACAD BRAS CIENC 2023; 95:e20220552. [PMID: 37585969 DOI: 10.1590/0001-3765202320220552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 11/01/2022] [Indexed: 08/18/2023] Open
Abstract
A fibrinolytic enzyme from the microalga Dunaliella tertiolecta was produced under mixotrophic conditions using different corn steep liquor (CSL) concentrations ( 0 ≤ CLS ≤ 0.75%), purified using a combination of salting out and ion-exchange chromatography, and then biochemical characterized. Cultivation of this microalga using 0.5% CSL led to the highest maximum cell concentration (1.960±0.010 mg L-1) and cell productivity (0.140g L-1 day-1), besides a high fibrinolytic activity of the extract obtained by the homogenization method (102 ±1 U mL-1). The enzyme extracted from the microalgal biomass was 5-fold purified with a 20% yield and was found to have a specific activity of 670 U mg-1. The enzyme, whose molecular weight determined by fibrin zymography was 10 kDa, was shown to be stable at pH 3.0-9.0 and up to 70°C with optimal pH and temperature values of 8.0 and 50°C, respectively. When compared to other fibrinolytic enzymes, this protease stood out for its high fibrinolytic activity, which was enhanced by Fe2+, inhibited by Zn2+, Cu2+, Mg2+, and Ca2+, and strongly inhibited by phenylmethylsulfonyl fluoride, suggesting that it belongs to the serine metalloprotease family. Moreover, thanks to its thermal stability, the enzyme may be easily preserved and activated under high-temperature conditions.
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Affiliation(s)
- Túlio A F DA Silva
- Federal Rural University of Pernambuco-UFRPE, Department of Animal Morphology and Physiology, Dom Manoel de Medeiros Ave., s/n, Dois irmãos, 52171-900 Recife, PE, Brazil
| | - Páblo E DA C E Silva
- Federal University of Pernambuco-UFPE, Laboratory of Immunopathology Keizo Asami (LIKA), Prof. Moraes Ave., s/n, Várzea, 50670-901 Recife, PE, Brazil
| | - Thiago P Nascimento
- Federal University of Piauí, Campus Professora Cinobelina Elvas, Br 135, Km 3, Planalto Horizonte, 64900-000 Bom Jesus, PI, Brazil
| | - Romero M P B Costa
- University of Pernambuco-UPE, Institute of Biological Sciences, 310, Arnóbio Marquês St., Santo Amaro, 50100-130 Recife, PE, Brazil
| | - Attilio Converti
- University of Genoa, Department of Civil, Chemical and Environmental Engineering, Pole of Chemical Engineering, via Opera Pia 15, 16145, 50100-130 Genoa, Italy
| | - Ana Lúcia F Porto
- Federal Rural University of Pernambuco-UFRPE, Department of Animal Morphology and Physiology, Dom Manoel de Medeiros Ave., s/n, Dois irmãos, 52171-900 Recife, PE, Brazil
- Federal University of Pernambuco-UFPE, Laboratory of Immunopathology Keizo Asami (LIKA), Prof. Moraes Ave., s/n, Várzea, 50670-901 Recife, PE, Brazil
| | - Raquel P Bezerra
- Federal Rural University of Pernambuco-UFRPE, Department of Animal Morphology and Physiology, Dom Manoel de Medeiros Ave., s/n, Dois irmãos, 52171-900 Recife, PE, Brazil
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Cell Separation and Disruption, Product Recovery, and Purification. ESSENTIALS IN FERMENTATION TECHNOLOGY 2019. [DOI: 10.1007/978-3-030-16230-6_8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Costa-Silva TA, Flores-Santos JC, Freire RKB, Vitolo M, Pessoa-Jr A. Microbial cell disruption methods for efficient release of enzyme L-asparaginase. Prep Biochem Biotechnol 2018; 48:707-717. [DOI: 10.1080/10826068.2018.1487850] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Tales A. Costa-Silva
- Department of Pharmaceutical and Biochemical Technology, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Juan Carlos Flores-Santos
- Department of Pharmaceutical and Biochemical Technology, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Rominne K. B. Freire
- Department of Pharmaceutical and Biochemical Technology, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Michele Vitolo
- Department of Pharmaceutical and Biochemical Technology, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
| | - Adalberto Pessoa-Jr
- Department of Pharmaceutical and Biochemical Technology, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil
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Hu Y, Cui X, Zhang Z, Chen L, Zhang Y, Wang C, Yang X, Qu Y, Xiong Y. Optimisation of Ethanol-Reflux Extraction of Saponins from Steamed Panax notoginseng by Response Surface Methodology and Evaluation of Hematopoiesis Effect. Molecules 2018; 23:E1206. [PMID: 29772847 PMCID: PMC6099958 DOI: 10.3390/molecules23051206] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 05/09/2018] [Accepted: 05/09/2018] [Indexed: 11/18/2022] Open
Abstract
The present study aims to optimize the ethanol-reflux extraction conditions for extracting saponins from steamed Panax notoginseng (SPN). Four variables including the extraction time (0.5⁻2.5 h), ethanol concentration (50⁻90%), water to solid ratio (W/S, 8⁻16), and times of extraction (1⁻5) were investigated by using the Box-Behnken design response surface methodology (BBD-RSM). For each response, a second-order polynomial model with high R² values (>0.9690) was developed using multiple linear regression analysis and the optimum conditions to maximize the yield (31.96%), content (70.49 mg/g), and antioxidant activity (EC50 value of 0.0421 mg/mL) for saponins extracted from SPN were obtained with a extraction time of 1.51 h, ethanol concentration of 60%, extraction done 3 times, and a W/S of 10. The experimental values were in good consistency with the predicted ones. In addition, the extracted SPN saponins could significantly increase the levels of blood routine parameters compared with the model group (p < 0.01) and there was no significant difference in the hematopoiesis effect between the SPN group and the SPN saponins group, of which the dose was 15 times lower than the former one. It is suggested that the SPN saponins extracted by the optimized method had similar functions of "blood tonifying" at a much lower dose.
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Affiliation(s)
- Yupiao Hu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.
| | - Xiuming Cui
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.
- Yunnan Key Laboratory of Panax notoginseng, Kunming University of Science and Technology, Kunming 650500, China.
- Laboratory of Sustainable Utilization of Panax notoginseng Resources, State Administration of Traditional Chinese Medicine, Kunming University of Science and Technology, Kunming 650500, China.
| | - Zejun Zhang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.
| | - Lijuan Chen
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.
| | - Yiming Zhang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.
| | - Chengxiao Wang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.
| | - Xiaoyan Yang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.
| | - Yuan Qu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.
| | - Yin Xiong
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.
- Yunnan Key Laboratory of Panax notoginseng, Kunming University of Science and Technology, Kunming 650500, China.
- Laboratory of Sustainable Utilization of Panax notoginseng Resources, State Administration of Traditional Chinese Medicine, Kunming University of Science and Technology, Kunming 650500, China.
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Zhu X, Sun J, Chu J. High-content screening of Aspergillus niger with both increased production and high secretion rate of glucose oxidase. Biotechnol Lett 2017; 40:103-110. [DOI: 10.1007/s10529-017-2442-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 09/13/2017] [Indexed: 01/05/2023]
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Byreddy AR, Rao NM, Barrow CJ, Puri M. Evaluation of cell disruption method for lipase extraction from novel thraustochytrids. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.04.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Lee Ying Yeng A, Kadir MSA, Ghazali HM, Raja Abd Rahman RNZ, Saari N. A comparative study of extraction techniques for maximum recovery of glutamate decarboxylase (GAD) from Aspergillus oryzae NSK. BMC Res Notes 2013; 6:526. [PMID: 24321181 PMCID: PMC4029468 DOI: 10.1186/1756-0500-6-526] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 12/06/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND γ-Amino butyric acid (GABA) is a major inhibitory neurotransmitter of the mammalian central nervous system that plays a vital role in regulating vital neurological functions. The enzyme responsible for producing GABA is glutamate decarboxylase (GAD), an intracellular enzyme that both food and pharmaceutical industries are currently using as the major catalyst in trial biotransformation process of GABA. We have successfully isolated a novel strain of Aspergillus oryzae NSK that possesses a relatively high GABA biosynthesizing capability compared to other reported GABA-producing fungal strains, indicating the presence of an active GAD. This finding has prompted us to explore an effective method to recover maximum amount of GAD for further studies on the GAD's biochemical and kinetic properties. The extraction techniques examined were enzymatic lysis, chemical permeabilization, and mechanical disruption. Under the GAD activity assay used, one unit of GAD activity is expressed as 1 μmol of GABA produced per min per ml enzyme extract (U/ml) while the specific activity was expressed as U/mg protein. RESULTS Mechanical disruption by sonication, which yielded 1.99 U/mg of GAD, was by far the most effective cell disintegration method compared with the other extraction procedures examined. In contrast, the second most effective method, freeze grinding followed by 10% v/v toluene permeabilization at 25°C for 120 min, yielded only 1.17 U/mg of GAD, which is 170% lower than the sonication method. Optimized enzymatic lysis with 3 mg/ml Yatalase® at 60°C for 30 min was the least effective. It yielded only 0.70 U/mg of GAD. Extraction using sonication was further optimized using a one-variable-at-a-time approach (OVAT). Results obtained show that the yield of GAD increased 176% from 1.99 U/mg to 3.50 U/mg. CONCLUSION Of the techniques used to extract GAD from A. oryzae NSK, sonication was found to be the best. Under optimized conditions, about 176% of GAD was recovered compared to recovery under non optimized conditions. The high production level of GAD in this strain offers an opportunity to conduct further studies on GABA production at a larger scale.
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Affiliation(s)
- Audrey Lee Ying Yeng
- Faculty of Food Science and Technology, University Putra Malaysia, 43400, Serdang, Selangor, D.E., Malaysia
| | - Mohd Safuan Ab Kadir
- Faculty of Food Science and Technology, University Putra Malaysia, 43400, Serdang, Selangor, D.E., Malaysia
| | - Hasanah Mohd Ghazali
- Faculty of Food Science and Technology, University Putra Malaysia, 43400, Serdang, Selangor, D.E., Malaysia
| | | | - Nazamid Saari
- Faculty of Food Science and Technology, University Putra Malaysia, 43400, Serdang, Selangor, D.E., Malaysia
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Optimization of ABTS radical cation assay specifically for determination of antioxidant capacity of intracellular extracts of microalgae and cyanobacteria. Food Chem 2012; 138:638-43. [PMID: 23265534 DOI: 10.1016/j.foodchem.2012.09.106] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2012] [Revised: 07/24/2012] [Accepted: 09/30/2012] [Indexed: 11/22/2022]
Abstract
A renewed interest in antioxidants has arisen in recent years; microalgae and cyanobacteria are potential sources thereof for use as food/feed ingredients. However, improved methods for comprehensive screening of antioxidant capacity specifically in intracellular extracts of marine microorganisms are required - encompassing lipophilic and hydrophilic compounds simultaneously. The original ABTS method was thus improved, and in particular the procedures of cell disruption and storage were optimized. The best solvent found was ethanol/water (1:1, v/v). The reaction to form ABTS(+) in said solvent was essentially complete by eight hours, and this radical cation was stable for at least 6 days; at room temperature, the ABTS(+) solution remained within an allowable analytical range for up to 13 h. Ultra Turrax was the best cell disruption method, and refrigeration was the best preservation method. This improved methodology was validated with four representative strains that respond poorly to cell disruption.
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Comparative study of fungal cell disruption--scope and limitations of the methods. Folia Microbiol (Praha) 2011; 56:469-75. [PMID: 21901292 PMCID: PMC3189342 DOI: 10.1007/s12223-011-0069-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 08/29/2011] [Indexed: 11/01/2022]
Abstract
Simple and effective protocols of cell wall disruption were elaborated for tested fungal strains: Penicillium citrinum, Aspergillus fumigatus, Rhodotorula gracilis. Several techniques of cell wall disintegration were studied, including ultrasound disintegration, homogenization in bead mill, application of chemicals of various types, and osmotic shock. The release of proteins from fungal cells and the activity of a cytosolic enzyme, glucose-6-phosphate dehydrogenase, in the crude extracts were assayed to determine and compare the efficacy of each method. The presented studies allowed adjusting the particular method to a particular strain. The mechanical methods of disintegration appeared to be the most effective for the disintegration of yeast, R. gracilis, and filamentous fungi, A. fumigatus and P. citrinum. Ultrasonication and bead milling led to obtaining fungal cell-free extracts containing high concentrations of soluble proteins and active glucose-6-phosphate dehydrogenase systems.
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Bankar SB, Bule MV, Singhal RS, Ananthanarayan L. Glucose oxidase--an overview. Biotechnol Adv 2009; 27:489-501. [PMID: 19374943 DOI: 10.1016/j.biotechadv.2009.04.003] [Citation(s) in RCA: 663] [Impact Index Per Article: 44.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Revised: 03/25/2009] [Accepted: 04/07/2009] [Indexed: 10/20/2022]
Abstract
Glucose oxidase (beta-D-glucose:oxygen 1-oxidoreductase; EC 1.1.2.3.4) catalyzes the oxidation of beta-D-glucose to gluconic acid, by utilizing molecular oxygen as an electron acceptor with simultaneous production of hydrogen peroxide. Microbial glucose oxidase is currently receiving much attention due to its wide applications in chemical, pharmaceutical, food, beverage, clinical chemistry, biotechnology and other industries. Novel applications of glucose oxidase in biosensors have increased the demand in recent years. Present review discusses the production, recovery, characterization, immobilization and applications of glucose oxidase. Production of glucose oxidase by fermentation is detailed, along with recombinant methods. Various purification techniques for higher recovery of glucose oxidase are described here. Issues of enzyme kinetics, stability studies and characterization are addressed. Immobilized preparations of glucose oxidase are also discussed. Applications of glucose oxidase in various industries and as analytical enzymes are having an increasing impact on bioprocessing.
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Affiliation(s)
- Sandip B Bankar
- Food Engineering and Technology Department, Institute of Chemical Technology, University of Mumbai, Matunga, Mumbai 400019, India
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12
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Pescheck M, Mirata MA, Brauer B, Krings U, Berger RG, Schrader J. Improved monoterpene biotransformation with Penicillium sp. by use of a closed gas loop bioreactor. J Ind Microbiol Biotechnol 2009; 36:827-36. [PMID: 19322596 DOI: 10.1007/s10295-009-0558-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Accepted: 03/06/2009] [Indexed: 11/29/2022]
Abstract
A closed gas loop bioprocess was developed to improve fungal biotransformation of monoterpenes. By circulating monoterpene-saturated process gas, the evaporative loss of the volatile precursor from the medium during the biotransformation was avoided. Penicillium solitum, isolated from kiwi, turned out to be highly tolerant towards monoterpenes and to convert alpha-pinene to a range of products including verbenone, a valuable aroma compound. The gas loop was mandatory to reproduce the production of 35 mg L(-1) verbenone obtained in shake flasks and also in the bioreactor. Penicillium digitatum DSM 62840 regioselectively converted (+)-limonene to the aroma compound alpha-terpineol, but shake flask cultures revealed a pronounced growth inhibition when initial concentrations exceeded 1.9 mM. In the bioreactor, toxic effects on P. digitatum during biotransformation were alleviated by starting a sequential feeding of non-toxic limonene portions after a preceding growth phase. Closing the precursor-saturated gas loop during the biotransformation allowed for an additional replenishment of limonene via the gas phase. The gas loop system led to a maximum alpha-terpineol concentration of 1,009 mg L(-1) and an average productivity of 8-9 mg L(-1) h(-1) which represents a doubling of the respective values previously reported. Furthermore, a molar conversion yield of up to 63% was achieved.
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Affiliation(s)
- Michael Pescheck
- Biochemical Engineering Group, DECHEMA eV, Karl-Winnacker-Institut, Frankfurt, Germany
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Exploration of fungal spores as a possible storehouse of proteolytic biocatalysts. World J Microbiol Biotechnol 2008. [DOI: 10.1007/s11274-008-9829-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Optimization of glucose-6-phosphate dehydrogenase releasing from Candida guilliermondii by disruption with glass beads. Enzyme Microb Technol 2006. [DOI: 10.1016/j.enzmictec.2005.11.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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Wu S, Zorn H, Krings U, Berger RG. Volatiles from submerged and surface-cultured beefsteak fungus,Fistulina hepatica. FLAVOUR FRAG J 2006. [DOI: 10.1002/ffj.1758] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Pescheck M, Schrader J, Sell D. Novel electrochemical sensor system for monitoring metabolic activity during the growth and cultivation of prokaryotic and eukaryotic cells. Bioelectrochemistry 2005; 67:47-55. [PMID: 15967400 DOI: 10.1016/j.bioelechem.2004.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2004] [Accepted: 10/12/2004] [Indexed: 10/25/2022]
Abstract
A novel amperometric sensor system is presented which directly reflects the metabolic activity of prokaryotic and eukaryotic cells during cultivation. The principle of an externally mounted sensor is current measurement using a three-electrode system. Only living cells are detected since the current signal is based on a redox mediator. Added to a culture sample in its oxidized form, the mediator is reduced by cellular metabolism and subsequently re-oxidized at the anode. The spontaneous immobilisation of the cells in the reaction vessel of the sensor by swelling dextrane polymers (Sephadex) prior to measurement is the key to a fast, consistent signal. Even metabolically less active mammalian cells produce a reliable signal within a few minutes; this may open up future applications of the electrochemical sensor in closed loop process control not only for bacterial and fungal bioprocesses, but also in cell culture technology.
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Affiliation(s)
- M Pescheck
- Biochemical Engineering Group, Karl-Winnacker-Institut der DECHEMA e.V., Theodor-Heuss-Allee 25, 60486 Frankfurt am Main, Germany
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Vongsangnak W, Gua J, Chauvatcharin S, Zhong JJ. Towards efficient extraction of notoginseng saponins from cultured cells of Panax notoginseng. Biochem Eng J 2004. [DOI: 10.1016/s1369-703x(03)00197-9] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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18
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Wong HC, Peng PY, Lan SL, Chen YC, Lu KH, Shen CT, Lan SF. Effects of heat shock on the thermotolerance, protein composition, and toxin production of Vibrio parahaemolyticus. J Food Prot 2002; 65:499-507. [PMID: 11899049 DOI: 10.4315/0362-028x-65.3.499] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Vibrio parahaemolyticus, an important seafood-associated enteropathogen, usually encounters different adverse conditions in its native or food-processing environment, and the stresses resulting from these conditions may affect the survival of this pathogen and thus change its risk with regard to food hygiene. In this study, we investigated the thermotolerance of V. parahaemolyticus under sublethal heat shock and characterized this response by examining the changes in protein profiles and toxin production. Logarithmically grown cells heat shocked at 42 degrees C for 30 min were more resistant to thermal inactivation at 47 degrees C than were unshocked cells. After the 25 degrees C culture was heat shocked, 24 species of proteins were induced, while 13 species were inhibited, as indicated by polyacrylamide gel electrophoresis. DnaJ-, GroEL-, and GroES-like proteins with molecular sizes of 47, 62, and 12 kDa, respectively, were detected by immunoblotting with antibodies raised against the Escherichia coli proteins. During 1 to 8 h of heat shock, GroEL-like protein was produced in substantial amounts and was present in the periplasmic and extracellular fractions, while DnaJ- and GroES-like proteins were present mainly in the total cellular fraction. DnaK-like protein was not detected; nevertheless, the presence of the dnaK-like genetic element was revealed by Southern blotting. Production of thermostable direct hemolysin, the major virulence factor in V. parahaemolyticus, was enhanced in the cells heat shocked at 42 degrees C but not in those heat shocked at 37 degrees C.
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Affiliation(s)
- Hin-Chung Wong
- Department of Microbiology, Soochow University, Taipei, Taiwan, Republic of China.
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