Effect of product inhibition patterns on the effectiveness factor of immobilized cell aggregates

1995 ◽  
Vol 59 (3) ◽  
pp. 309-314 ◽  
Author(s):  
G.A. Dervakos ◽  
C. Webb
Keyword(s):  
Product Inhibition ◽  
Effectiveness Factor ◽  
Cell Aggregates ◽  
Immobilized Cell

scholarly journals Pre-purification of Plantago lanceolata extracts with biologically active compounds using yeast cells

2018 ◽  
Vol 11 (2) ◽  
pp. 163-169
Author(s):  
Vladimír Štefuca ◽  
Lukáš Rada ◽  
Alžbeta Chochulová ◽  
Michal Rosenberg
Keyword(s):  
Mass Transfer ◽  
Plantago Lanceolata ◽  
Packed Bed ◽  
Point Of View ◽  
Production Costs ◽  
Biologically Active ◽  
Effectiveness Factor ◽  
Packed Bed Reactor ◽  
Yeast Cells ◽  
Immobilized Cell

AbstractLeaves of the plantPlantago lanceolatacontain many economically interesting bioactive compounds, among them aucubin and catalpol are the most attractive. However, soluble saccharides passing to water extracts during isolation complicate chromatographic purification of these compounds. Their degradation by microbial cells transforming, for example, glucose, fructose, or sucrose to ethanol could bring important production costs savings and improved final product quality. It has been shown that the best saccharide degradation in extracts is achieved with theSaccharomyces cerevisiaecells. The cells were very active also in their immobilized form and they were able to completely remove glucose from the extract within four hours in a packed bed reactor combined with a stirring system with infinite medium recirculation.A simple mathematical model involving reaction kinetics and mass transfer limitations in the cell particles was proposed for the evaluation of cell effectiveness in their immobilized form in term of effectiveness factor. Values of the effectiveness factor calculated from the model were far below 1, indicating strong mass transfer limitations of the reaction. The model is suitable for optimization of preparation of immobilized cell particles, mainly from the point of view of cell charge in particles.

Product inhibition influence on immobilized cell biocatalyst performance

1990 ◽  
Vol 6 (2) ◽  
pp. 153-158 ◽  
Author(s):  
Gregory D. Sayles ◽  
David F. Ollis
Keyword(s):  
Product Inhibition ◽  
Immobilized Cell

scholarly journals Estimation of the Effectiveness Factor for Immobilized Enzyme Catalysts through a Simple Conversion Assay

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 930 ◽  
Author(s):  
Pedro Valencia ◽  
Francisco Ibañez
Keyword(s):  
Immobilized Enzyme ◽  
Batch Reactor ◽  
Product Inhibition ◽  
Effectiveness Factor ◽  
Order Kinetic ◽  
Soluble Enzyme ◽  
Enzyme Catalyst ◽  
Reaction Orders ◽  
Simple Conversion ◽  
Behavior Profile

A novel methodology to estimate the effectiveness factor (EF) of an immobilized enzyme catalyst is proposed here. The methodology consists of the determination of the productivity of both the immobilized enzyme catalyst and its corresponding soluble enzyme, plotted as a function of the reaction conversion. The ratio of these productivities corresponds to the EF estimator of the catalyst. Conversion curves were simulated in a batch reactor with immobilized enzyme and soluble enzyme for different values of the S0/KM ratio and Thiele modulus (Φ) to demonstrate this hypothesis. Two different reaction orders were tested: first-order kinetic and Michaelis–Menten-based kinetic with product inhibition. The results showed that the ratio of productivities between the immobilized and soluble enzymes followed the behavior profile presented by the EF with satisfactory agreement. This simple methodology to estimate the EF is based on routine conversion experiments, thus avoiding the exhaustive kinetic and mass transfer characterization of the immobilized enzyme catalyst.

Effects of carbamylcholine on chick embryo aggregate retina cell cultures

1988 ◽  
Vol 46 ◽  
pp. 350-351
Author(s):  
Glenn M. Cohen ◽  
Radharaman Ray
Keyword(s):  
Cell Cultures ◽  
Single Cells ◽  
Retinal Cell ◽  
Cell Aggregates ◽  
High Concentration ◽  
In Ovo ◽  
Sterile Culture ◽  
Retinal Tissue ◽  
Synaptic Junctions ◽  
And Control

Retinal,cell aggregates develop in culture in a pattern similar to the in ovo retina, forming neurites first and then synapses. In the present study, we continuously exposed chick retinal cell aggregates to a high concentration (1 mM) of carbamylcholine (carbachol), an acetylcholine (ACh) analog that resists hydrolysis by acetylcholinesterase (AChE). This situation is similar to organophosphorus anticholinesterase poisoning in which the ACh level is elevated at synaptic junctions due to inhibition of AChE, Our objective was to determine whether continuous carbachol exposure either damaged cholino- ceptive neurites, cell bodies, and synaptic elements of the aggregates or influenced (hastened or retarded) their development.The retinal tissue was isolated aseptically from 11 day embryonic White Leghorn chicks and then enzymatically (trypsin) and mechanically (trituration) dissociated into single cells. After washing the cells by repeated suspension and low (about 200 x G) centrifugation twice, aggregate cell cultures (about l0 cells/culture) were initiated in 1.5 ml medium (BME, GIBCO) in 35 mm sterile culture dishes and maintained as experimental (containing 10-3 M carbachol) and control specimens.

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