摘要:

AbstractOxygen transfer coefficient and oxygen respiration rate measurements in stirred tank reactors or fermentors have been carried out utilizing currently available dissolved oxygen electrodes. Techniques based on previously derived theory1have been put to experimental tests and found to adequately describe the oxygen transfer phenomena observed in air–water systems and a fermenting brot

ISSN:0006-3592    

DOI:10.1002/bit.260130502

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

年代:1971

数据来源: WILEY

摘要:

AbstractA detailed study of anaerobic yeast fermentations requires controlled addition of minor amounts of oxygen to the fermentor. A method for supplying small‐scale fermentations with millimolar amounts of oxygen is described. The controlled addition is accomplished by diffusion of oxygen through silicone tubing carrying nitrogen to the fermentor. Sulfite values of the fermentation system are given for different gas velocities and lengths of silicone tubing. Two experiments are outlined in which this technique is applied and the possible energy yield from oxydative phosphorylation is discusse

ISSN:0006-3592    

DOI:10.1002/bit.260130503

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

年代:1971

数据来源: WILEY

摘要:

AbstractConstant current voltametry was shown to be a suitable method for evaluation of electrodes containing immobilized oxidative enzymes as catalysts. The half‐cell potential for the oxdidation ofD‐glucose at constant pH was measured at a series of constant dc currents, using glucose oxidase immobilized in a polyacrylamide gel‐platinum gauze matrix as catalyst. Over the range studied the potential versus current data were linear and could be extrapolated to give the open‐circuit half‐cell potential at zero current. The difference between the measured potential and the open‐circuit potential at a constant current was indicative of the loss in useful voltage due to concentration gradients within or adjacent to the enzyme electrode assembly. The relationship between the open‐circuit potential and the pH of the reaction mixture was linear with a slope of −0.056, in good agreement with the predicted

ISSN:0006-3592    

DOI:10.1002/bit.260130504

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe kinetics of the enzymatic hydrolysis of sucrose by invertase have been examined, with particular emphasis on high substrate concentration. Initial rates of reaction were determined by following the production of glucose directly as a function of time over a wide range of substrate concentrations (0.04Mto 2.06M). The resulting data reveal a reaction rate that increases gradually until the sucrose concentration reaches about 0.29M, after which the reaction velocity decreases with increasing sucrose concentration. Previous workers (e.g., Nelson and Schubert1) have reported a peak reaction velocity as determined by indirect polarimetric measurements of glucose, at a sucrose concentration of about 0.17M. These measurements, however, neglect the intermediate oligosaccharides formed by the transferase action of invertase,8–10and assume equal amounts of glucose and fructose. According to Andersonet al.,10these oligosaccharides interfere by producing an erroneously low reaction rate. Experimental results of this work confirm Anderson's observations, and show a further reaction rate increase of nearly 20% between sucrose concentrations of 0.177M and 0.285M under the same conditions of temperature, pH, and enzyme‐concentration.Effects of substrate diffusion, solution viscisity, water concentration, and substrate inhibition were experimentally studied and the results incorporated into a kinetic model that has proven satisfactory in modeling the experimental results. This model takes into account inhibition by primary substrate, with concentration of the secondary substrate water, as a rate limiting factor at sucrose concentrations greater than 0.285M.The effects of the mixing, in terms of volumetric power input, on the relation rate have been tested. Approximately 40‐fold increase in volumetric power input caused on increase in the reaction rate. These experiments have shown that bulk mass transfer is not a rate limiting factor under the experimental condi

ISSN:0006-3592    

DOI:10.1002/bit.260130505

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

年代:1971

数据来源: WILEY

摘要:

AbstractTetrahymenawas continuously cultivated in a series of stirred tank reactors with recycle. By holding part of the reactor train at a higher temperature than the remainder a synchronizing influence was introduced into the cells' environment. The system resulted in division occurring preferentially in a small contiguous group of the reactors, this effect being observed in both the number of cells found in each reactor and also their size distribution.

ISSN:0006-3592    

DOI:10.1002/bit.260130506

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

年代:1971

数据来源: WILEY

摘要:

AbstractMass transfer coefficients and interfacial areas were determined for the aeration of aqueous solutions in a turbine agitated vessel. The mass transfer coefficients measured for water without additive and for sodium chloride solutions matched very well to measurements in the literature for air bubbles of the same diameter in free rise. Thus the only effect of agitation was to determine the bubble size which then in turn set the coefficient. Two surface active agents were studied: sodium dodecyl sulfate and Dow Corning Antifoam C. Therateof mass transfer increased with the former additive but decreased with the latter; however, the mass transfer coefficient was the exact same function of bubble diameter in both cases and the different rates are attributed to the quite different effects on interfacial area.

ISSN:0006-3592    

DOI:10.1002/bit.260130507

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

年代:1971

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260130508

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

年代:1971

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260130509

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

年代:1971

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260130510

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

年代:1971

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260130511

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

年代:1971

数据来源: WILEY