ISSN:0006-3592    

DOI:10.1002/bit.260080102

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

年代:1966

数据来源: WILEY

摘要:

AbstractScale‐up of a mixing process in fermentation involves breaking the process down into individual but interrelated steps. The effect of mixing on gas‐liquid absorption, fluid shear rates, blending, and heat transfer allows each to be considered separately. A method of estimating the mixer size required in a full‐scale system from pilot studies illustrates the application of a particular tech

ISSN:0006-3592    

DOI:10.1002/bit.260080103

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

年代:1966

数据来源: WILEY

摘要:

AbstractThe effects on mass‐transfer and overall mixing rates of varying impeller geometry and operating speed have been studied for flat‐bladed turbines in laboratory fermentors, in aerated aqueous solutions, and in unaerated and aerated suspensions (1.6% w/v) of paper pulp. In the absence of suspended solid, oxygen absorption rates could be correlated directly with power input. In the pulp suspension, oxygen absorption at a given power input was influenced by impeller geometry and operating speed. The data for the three‐phase system can be correlated by a dimensionless equation relating oxygen‐transfer rates and mixing times to the geometrical and operating parameters of the im

ISSN:0006-3592    

DOI:10.1002/bit.260080104

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

年代:1966

数据来源: WILEY

摘要:

AbstractPower requirements in the agitation of non‐Newtonian fermentation broths with and without aeration were measured by a strain gage‐type dynamometer. Broth from the production of gluc‐amylase byEndomycesspecies and carboxymethyl cellulose solutions were used as non‐Newtonian fluids. In gas–liquid agitation systems, the correlation betweenPgandP02ND3/Q0.56observed by Michel and Miller was found to be applicable to non‐Newtonian fluids in laminar and transition regions. This was particularly true for fluids with apparent viscosities larger than 300 cp. The impeller diameter and impeller blade width had considerable effects on power consumption in a nongassed system. It was suggested, therefore, thatPg/P0should be correlated by a dimensionless term involving some impeller

ISSN:0006-3592    

DOI:10.1002/bit.260080105

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

年代:1966

数据来源: WILEY

摘要:

AbstractBy means of gas‐absorption experiments in a stirred vessel, with various depths of liquid above a properly positioned single‐opening pipe‐type gas sparger, conclusions are reached about relative contributions to the overall absorption rate by localized actions near the sparger tip, in the impeller region, and from bubbles distributed in the bulk volume of the fluid. Results are discussed for difficulty soluble gases (oxygen in water and chlorine in water) and a substantially soluble gas (chlorine in benzene). In all cases, dissolution rates in the vicinity of the sparger and impeller were significantly large compared with those near free bu

ISSN:0006-3592    

DOI:10.1002/bit.260080106

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

年代:1966

数据来源: WILEY

摘要:

AbstractA model system, utilizing shear‐sensitive protozoa, has been developed for characterizing the disruptive forces in agitated systems. The model system gives a measure of the maximum shear stresses in the apparatus being tested, and is particularly useful when tissue fragility is a factor in fermentor design. The time dependency of protozoan disruption is shown and discussed. Breakdown data in conventional stirred vessels and a laminar shear device are presented and discusse

ISSN:0006-3592    

DOI:10.1002/bit.260080107

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

年代:1966

数据来源: WILEY

摘要:

AbstractPreviously, the degree of mixing was not felt to be an important consideration in fermentor design. In this study on the continuous propagation of Baker's yeast, it was found that at low dilution rates, i.e., 0.02hr−1, the degree of mixing achieved does effect the cell yield. At low dilution rates, appreciable quantities of sugar can be utilized for endogenous respiration in comparison to that utilized for making cell mass. Poor distribution of the sugar aggravates the balance of sugar utilized for each process. Yields at these low dilution rates can be improved to a limited extent by using a multiple feed‐distribution system and better mix

ISSN:0006-3592    

DOI:10.1002/bit.260080108

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

年代:1966

数据来源: WILEY

摘要:

AbstractDissolved oxygen measurements were made in pilot (20 and 250 l.) and production scale (15,000 l.) novobiocin fermentations. Bulk mixing was found to be incomplete in pilot tanks with turbine impellers ofD/T= 0.40 (whereDis impeller diameter, andTis tank diameter) but appeared homogeneous with impellers ofD/T= 0.69. In the former case, the respiration rate was presumably limited by insufficient oxygen supply in areas of poor bulk mixing, whereas, in the latter case, the major resistance was between the bulk of the liquid and the cell (intraclump resistance). Higher agitator speeds decreased the gas–liquid resistance proportionally more than they reduced the liquid‐cell resistance. In production fermentors, dissolved oxygen measurements indicated that bulk mixing was complete with each of the three impeller sizes tested (D/T= 0.28, 0.33, and 0.43), but that the respiration rate was again limited, mainly by a resistance between the bulk of the liquid and the c

ISSN:0006-3592    

DOI:10.1002/bit.260080109

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

年代:1966

数据来源: WILEY

摘要:

AbstractThe performance of a multiple‐rod mixing impeller was compared to that of conventional turbine impellers in viscous novobiocin beers. The advantages of the multiple‐rod impeller were found to be: (1) the power requirement was independent of changes in apparent viscosity of the fermentation beer; and (2) it gave the same novobiocin yield and oxygen‐availability rate at about one‐half of the power required by t

ISSN:0006-3592    

DOI:10.1002/bit.260080110

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

年代:1966

数据来源: WILEY

摘要:

AbstractA system of automatic control of substrate inflow into an aerated culture of microorganisms which depend on oxygen‐absorption rate (OAR) has been devised and tested. As the control variable, dissolved oxygen concentration (DOC), which shows the equilibrium between OAR and oxygen‐uptake rate in the microbial culture, was chosen. If the equilibrium is disturbed by changes in OAR, then the oxygen‐uptake rate is changed by substrate limitation. The DOC is measured by means of a Clark‐type polarographic electrode, and the signal is used to actuate the substrate inflow valve or pump. The oxygen‐uptake rate changes of microorganisms, after the addition or exhaustion of substrate in the medium, are so rapid that they can be used for this type of control.Fundamental equations were derived and graphical solutions for the control system parameters were suggested for the steady‐state relations between DOC, oxygen‐uptake rate, specific growth rate, substrate concentration,KLa, and concentration of microorganisms. The system is stable in the entire range of the uptake rates up to nearly the maximum attainable in unlimited substrate conditions, and can be operated in batch feed or continuous flow modifications. It was experimentally tested with the yeastSaccharomyces cerevisiae. The complete utilization of aeration‐system capacity of the fermentor was achieved with high yeast yield and no alcohol formation. The quality of the produc

ISSN:0006-3592    

DOI:10.1002/bit.260080111

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

年代:1966

数据来源: WILEY