摘要:

AbstractRates of glucose oxidation were measured with the use of a fluidized‐bed column placed in a magnetic field and magnetite‐containing beads of immobilized glucose oxidase and catalase. Its performance was predicted from the volumetric coefficient for liquid‐phase mass transfer and the kinetic constants for glucose oxidation. Effusion of beads was negligible under the operating conditions emp

ISSN:0006-3592    

DOI:10.1002/bit.260251002

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractBaker's yeast,Saccharomyces cerevisiae, was investigated for the combined influence of dissolved oxygen and glucose concentration in continuous culture. A reactor was operated at a range of dilution rates (0.1, 0.2, 0.25, 0.27, and 3.0 h−1), above and below the critical value that separates the oxidative and fermentation regions. For each dilution rate (D), steady states were established at each of five to ten different dissolved oxygen concentrations (DO) in the range of 0.01−5 mg/L. The use of on‐line mass spectrometry facilitated the measurement of gaseous and dissolved O2, CO2, and ethanol. Intracellular carbohydrate, protein, RNA, DNA, lipid, and cytochrome concentrations were measured. Cell size measurements were reduced to specific surface areas. Cytochrome content showed up to 100% variation during a 20‐day period of adaptation atD= 0.2 h−1to low DO. Eventually, the culture behaved the same at DO = 0.05 mg/L as it did initially at 3 mg/L. AtD= 0.2, 0.25, and 0.27 h−1, the transition between oxidation and fermentation was characterized by a critical DO which decreased with decreasingD. TheX‐Dcurves were shifted such that the criticalDvalue was reduced with decreasing DO. Specific oxygen update rates varied with DO according to the saturation kinetics. Specific cell surface areas increased with decreasing DO. Cytochrome content generally decreased with decreasing DO, andQ O 2could be linearly related to the total cytochrome content, which exhibited a maxi

ISSN:0006-3592    

DOI:10.1002/bit.260251003

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractArrays of foils similar in design to airplane wings have been placed in an algal culture flume to create systematic mixing. Vortices are produced in the culture due to the pressure differential created as water flows over and under the foils. In a flume having a flow rate of 30 cm/s, the foil arrays produced vortices with rotation rates of ca. 0.5−1.0 Hz. This rotation rate is satisfactory to take advantage of the flashing light effect if the culture is sufficiently dense. Solar energy conversion efficiencies in an experimental culture ofP. tricornutumincreased 2.2–2.4 fold with the foil arrays in place versus controls with no foil arrays and solar energy conversion efficiencies averaged 3.7% over a three‐month period. Five‐day running means of solar energy conversion efficiencies reached as high as 10% during the three‐month period. The use of foil arrays appears to be an effective and inexpensive way to utilize the flashing light effect in a dense algal cultu

ISSN:0006-3592    

DOI:10.1002/bit.260251004

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractIt has been observed experimentally that the biodegradation of 2,4‐dichlorophenoxyacetate (2,4‐D) is inhibited by the presence of glucose. However, this effect is masked by the fact that larger concentrations of active biomass are produced when glucose is available. The implication of such a “mixed” growth in a continuous flow system is that much higher dilution rates can be applied for an efficient chlorinated‐organic removal when other conventional substrates are present. The mean cell residence time is reduced and the area of stability of the process is extended into higher dilution rates, as well as into higher influent concentrations. Finally, the presence of the mixed substrate changes dramatically the “washout” conditions for both substrates. All these facts point out that the biodegradation of chlorinated organics is more efficient in a mixed substrat

ISSN:0006-3592    

DOI:10.1002/bit.260251005

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThis article concerns the development of a simple and effective least‐squares procedure for estimating the kinetic parameters in Monod expressions from batch culture data. The basic approach employed in this work was to translate the problem of parameter estimation to a mathematical model containing a single decision variable. The resulting model was then solved by an efficient one‐dimensional search algorithm which can be adapted to any microcomputer or advanced programmable calculator. The procedure was tested on synthetic data (substrate concentrations) with different types and levels of error. The effect of endogeneous respiration on the estimated values of the kinetic parameters was also assessed. From the results of these analyses the least‐squares procedure developed was concluded to be very effe

ISSN:0006-3592    

DOI:10.1002/bit.260251006

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractA rotating drum fermentor designed for plant cell suspension cultures was constructed and tested. The oxygen transfer coefficient (kLa) and power requirements in the fermentor were determined with the water system under various conditions and the relationship between them in the fermentor was clarified. Also, the relationship betweenkLaand the apparent viscosity in the fermentor was investigated in the cell suspension system. The rotating drum fermentor was found to be superior to the mechanically agitated fermentor in the capacity of oxygen supply under high viscosity and low hydrodynamic stress conditions. This finding was also confirmed by the experiments with plant cell suspension cultures.

ISSN:0006-3592    

DOI:10.1002/bit.260251007

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractA process for producing a higher‐fructose syrup containing more than 50% fructose was developed that involves a new system combining selective adsorption of fructose and an immobilized glucose isomerase reaction. Continuous countercurrent contact of the liquid stream with the solid adsorbent is simulated by advancing adsorption columns against the fixed inlets and outlet of liquid streams without actual movement of the solid adsorbent, while the immobilized enzyme reactors are stationary. Two mathematical models, an intermittent moving‐bed and a continuous moving‐bed model, are presented for calculation the concentration profiles of glucose and fructose in the system. The validity of the models is experimentally confirmed, and a criterion for good production in the system is presented. This system requires less desorbent than a process using a fixed‐bed adsorber and a simulated moving‐bed process to produce the syrup with 45−65% fructose content, the level desired in food

ISSN:0006-3592    

DOI:10.1002/bit.260251008

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractProduction of cellulase fromPestalotiopsis versicolorwas studied in a shake flask culture. The cellulase system was found to be rich in β‐glucosidase. Kinetic parameters such as pH and temperature have been optimized for the various enzyme componen

ISSN:0006-3592    

DOI:10.1002/bit.260251009

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractA novel 2.0‐L columnar reactor has been developed for the production of thienamycin by cells ofStreptomyces cattleyaattached to celite particles. Successful immobilization of cells was achieved by operating the column continuously at a high dilution rate during the growth phase. Scanning electron micrographs of the celite particles indicate the involvement of subcellular fibrils in the attachment of cells to the solid surfaces. Reactor operation was divided into two distinct phases–a growth phase and a production phase. The kinetics of attached growth and thienamycin production were found to be strongly influenced by nutrient concentrations. The influences of nutrient concentration on CO2production and thienamycin production during both the growth phase and the production phase are discus

ISSN:0006-3592    

DOI:10.1002/bit.260251010

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY

摘要:

AbstractThe kinetics of the cellulase‐catalyzed conversion of soluble cellulose into glucose have been studied over a range of substrate concentrations and temperatures, and at pH values ranging from 4.75 to 7.0. Lineweaver‐Burk plots were linear and led toV= 6.2μM/s andKm= 13.1 mMat pH 5.8 and 25.0°C. The pK values corresponding to the free enzyme are 4.8 and 6.8 and are consistent with carboxyl and imidazole groups as the active ionizing species. These pK values were little changed in the enzyme‐substrate intermediate that reacts in the ratedetermining step, suggesting that the ionizing groups are still free in this intermediate. The activation energy corresponding toV/Kmis 80.6 kJ/mol, and that corresponding toVis 38.7 kJ/mol. The corresponding entropies of activation are 21 J K−1mol−1and –157 J K−1mol

ISSN:0006-3592    

DOI:10.1002/bit.260251011

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1983

数据来源: WILEY