Mass transfer in aerated culture media combining mixed electrolytes and glucose

The present study addresses the behavior of gases in cultivation media as an essential factor to develop the relationship between the microorganisms that are present in the same environment. This relationship was explained via mass transfer of those gases to be a reasonable driving force in changing biological trends. Stripping and dissolution of oxygen and carbon dioxide in water and dairy wastewater were investigated in this study. Bubble column bioreactor under thermal control system was constructed and used for these processes. The experimental results showed that the removal of gases from the culture media requires more time than the dissolution. For example, the volumetric mass transfer coefficient for the removal of oxygen is 1.67 min-1 while the volumetric mass transfer coefficient for dissolution the same gas is 3.18 min-1. The same thing occurred with carbon dioxide, where the data showed that the volumetric mass transfer coefficient of the dissolution of CO2 is 0.66 min-1 while the volumetric mass transfer coefficient for removal process is 0.374 min-1. However, the two processes (dissolution and removal) with CO2 take more time than that with O2. Therefore, the production of gases due to metabolic processes in bacteria or microalgae remains in culture’s media for a certain period even if that media is sparged by air. Thus, this will give enough time for both microorganisms to consume those gases. Keywords: Bioreactor, mass transfer, microalgae, aerobic bacteria The present study addresses the behavior of gases in cultivation media as an essential factor to develop the relationship between the microorganisms that are present in the same environment. This relationship was explained via mass transfer of those gases to be a reasonable driving force in changing biological trends. Stripping and dissolution of oxygen and carbon dioxide in water and dairy wastewater were investigated in this study. Bubble column bioreactor under thermal control system was constructed and used for these processes. The experimental results showed that the removal of gases from the culture media requires more time than the dissolution. For example, the volumetric mass transfer coefficient for the removal of oxygen is 1.67 min-1 while the volumetric mass transfer coefficient for dissolution the same gas is 3.18 min-1. The same thing occurred with carbon dioxide, where the data showed that the volumetric mass transfer coefficient of the dissolution of CO2 is 0.66 min-1 while the volumetric mass transfer coefficient for removal process is 0.374 min-1. However, the two processes (dissolution and removal) with CO2 take more time than that with O2. Therefore, the production of gases due to metabolic processes in bacteria or microalgae remains in culture’s media for a certain period even if that media is sparged by air. Thus, this will give enough time for both microorganisms to consume those gases.

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MASS TRANSFER IN FERMENTATION PROCESSES

Food Science and Technology ◽

10.15673/fst.v12i1.846 ◽

2018 ◽

Vol 12 (1) ◽

Cited By ~ 1

Author(s):

A. Shevchenko ◽

A. Sokolenko ◽

O. Stepanets ◽

O. Bilyk

Keyword(s):

Mass Transfer ◽

Liquid Phase ◽

Culture Media ◽

Anaerobic Fermentation ◽

Superposition Principle ◽

Cumulative Effect ◽

Unsaturation Index ◽

Yeast Cells ◽

Fermentation Processes ◽

The Media

The peculiarities of anaerobic fermentation processes with the accumulation of dissolved ethyl alcohol and carbon dioxide in the culture media are considered in the article.The solubility of CO2 is limited by the state of saturation in accordance with Henry’s law. This, with all else being equal, limits the mass transfer on the interface surface of yeast cells and the liquid phase of the medium. A phenomenological model of the media restoration technologies based on the unsaturation index on СО2 is developed. It is shown that this restoration in the existing technologies of fermentation of sugar-rich media occurs, to a limited extent, in self-organized flow circuits, with variable values of temperatures and hydrostatic pressures, due to the creation of unsaturated local zones.It is shown that increasing the height of the media in isovolumetric apparatuses leads to an increase in the levels of flow circuits organization and to the improvement of the desaturation and saturation modes of the liquid phase and intensification of mass transfer processes. Among the deterministic principles of restoring the saturation possibilities of the media, there are forced variables of pressures with time pauses on their lower and upper levels. In such cases, the possibilities of short-term intensive desaturations in full media volumes, the restoration of their saturation perception of CO2, and the activation of fermentation processes are achieved. This direction is technically feasible for active industrial equipment.The cumulative effect of the action of variable pressures and temperatures corresponds to the superposition principle, but at the final stages of fermentation, the pressure and temperature values are leveled, so the restoration of the unsaturation state slows down to the level of the bacteriostatic effect. The possibility of eliminating the disadvantages of the final stage of fermentation by means of programmable variable pressures is shown

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High-pressure freezing of cells in suspension for low-voltage scanning electron microscopy (LVSEM)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084624 ◽

1991 ◽

Vol 49 ◽

pp. 64-65

Author(s):

Marek Malecki ◽

James Pawley ◽

Hans Ris

Keyword(s):

Electron Microscopy ◽

High Pressure ◽

Low Voltage ◽

Culture Media ◽

Cell Structure ◽

Freeze Substitution ◽

Ice Crystal ◽

High Pressure Freezing ◽

Cell Culture Media ◽

Voltage Scanning

The ultrastructure of cells suspended in physiological fluids or cell culture media can only be studied if the living processes are stopped while the cells remain in suspension. Attachment of living cells to carrier surfaces to facilitate further processing for electron microscopy produces a rapid reorganization of cell structure eradicating most traces of the structures present when the cells were in suspension. The structure of cells in suspension can be immobilized by either chemical fixation or, much faster, by rapid freezing (cryo-immobilization). The fixation speed is particularly important in studies of cell surface reorganization over time. High pressure freezing provides conditions where specimens up to 500μm thick can be frozen in milliseconds without ice crystal damage. This volume is sufficient for cells to remain in suspension until frozen. However, special procedures are needed to assure that the unattached cells are not lost during subsequent processing for LVSEM or HVEM using freeze-substitution or freeze drying. We recently developed such a procedure.

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Kalinin: A new epithelial basement membrane adhesion molecule

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100085198 ◽

1991 ◽

Vol 49 ◽

pp. 178-179

Author(s):

Douglas R. Keene ◽

Gregory P. Lunstrum ◽

Patricia Rousselle ◽

Robert E. Burgeson

Keyword(s):

Basement Membrane ◽

Culture Media ◽

Polyacrylamide Gel Electrophoresis ◽

Human Keratinocytes ◽

Positive Staining ◽

Human Amnion ◽

Epithelial Basement Membrane ◽

Type Vii Collagen ◽

Keratinocyte Cell ◽

Epithelial Basement

A mouse monoclonal antibody produced from collagenase digests of human amnion was used by LM and TEM to study the distribution and ultrastructural features of an antigen present in epithelial tissues and in cultured human keratinocytes, and by immunoaffinity chromatography to partially purify the antigen from keratinocyte cell culture media.By immunofluorescence microscopy, the antigen displays a tissue distribution similar to type VII collagen; positive staining of the epithelial basement membrane is seen in skin, oral mucosa, trachea, esophagus, cornea, amnion and lung. Images from rotary shadowed preparations isolated by affinity chromatography demonstrate a population of rod-like molecules 107 nm in length, having pronounced globular domains at each end. Polyacrylamide gel electrophoresis suggests that the size of this molecule is approximately 440kDa, and that it is composed of three nonidentical chains disulfide bonded together.

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Structural integrity after cold storage of human epidermal model in hypothermosol: A correlative ultrastructural and fluorescent assay

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100169080 ◽

1994 ◽

Vol 52 ◽

pp. 270-271

Author(s):

Henry H. Eichelberger ◽

John G. Baust ◽

Robert G. Van Buskirk

Keyword(s):

Cold Storage ◽

Structural Integrity ◽

Culture Media ◽

Cell Structure ◽

Natural State ◽

Sodium Cacodylate ◽

Ruthenium Tetroxide ◽

Cacodylate Buffer ◽

Before And After

For research in cell differentiation and in vitro toxicology it is essential to provide a natural state of cell structure as a benchmark for interpreting results. Hypothermosol (Cryomedical Sciences, Rockville, MD) has proven useful in insuring the viability of synthetic human epidermis during cold-storage and in maintaining the epidermis’ ability to continue to differentiate following warming.Human epidermal equivalent, EpiDerm (MatTek Corporation, Ashland, MA) consisting of fully differentiated stratified human epidermal cells were grown on a microporous membrane. EpiDerm samples were fixed before and after cold-storage (4°C) for 5 days in Hypothermosol or skin culture media (MatTek Corporation) and allowed to recover for 7 days at 37°C. EpiDerm samples were fixed 1 hour in 2.5% glutaraldehyde in sodium cacodylate buffer (pH 7.2). A secondary fixation with 0.2% ruthenium tetroxide (Polysciences, Inc., Warrington, PA) in sodium cacodylate was carried out for 3 hours at 4°C. Other samples were similarly fixed, but with 1% Osmium tetroxide in place of ruthenium tetroxide. Samples were dehydrated through a graded acetone series, infiltrated with Spurrs resin (Polysciences Inc.) and polymerized at 70°C.

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