摘要:

AbstractSpherical beads of κ‐carrageenan containing entrapped cells were prepared in a two‐step process. First, the beads were formed by dispersing a warm carrageenan cell suspension into stirring oil. After cooling (gelation) the beads were cured by treatment with amines. Ten amines of various sizes and structures were tested. We evaluated the mechanical strength and the applicability of aminetreated gels as immobilization matrices. The results of critical compression tests indicate that linear and branched polyethylenimines (PEI) are both good curing agents. PEI treated carrageenan beads also exhibited superior resistance to heat and abrasion. Furthermore, PEI polymers were demonstrated to be effective in stabilizing the lactase activity of the free and immobilizedBacillus stearothermophiluscells. The immobilized cell preparations ofSaccharomyces cerevisiae, B. stearothermophilus, andFlavobacteriumsp. were treated with branched PEI and evaluated for the activity of invertase (EC 3.2.1.26), lactase (EC 3.2.1.23), and glucose isomerase (EC 5.3.1.18), respectively, in a packed bed reactor at 60°C. The apparent half‐lives were 108, 39, and 64 days, respe

ISSN:0006-3592    

DOI:10.1002/bit.260280902

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe productivity of a cell mass ofSaccharomyces cerevisiaeand enzymes ofEupenicillium javanicumincreased by cultivation in anair–solid fluidized bed fermentor with agitators. The usefulness of the apparatus for the fluidized bed culture was verified. The productivity of amyiase and protease of the fungus by fluidized bed culture was twice as high as that by stationary culture, considering the dry weight of cells and the enzyme activity. Physiological properties of yeast cells were changed buy the fluidized bed culture; there was a decrease in the cell size of yeast and the changes to the aerobic properties of the yeast cells resulting from excessive supply of oxygen with a high flowrate of ai

ISSN:0006-3592    

DOI:10.1002/bit.260280903

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe penetration of ultrasonic waves through opaque media and the large difference in the acoustic properties between air bubbles and the fermentation broth were used to measure the energy attenuation of pulsed ultrasound by the bubbles as the waves passed through the broth. This leads to an on‐line determination of the specific interfacial area provided information is available about the holdup or bubble mean diameter. This article gives the principle of the method and demonstrates how the measured interfacial area may be used in evaluating the mass transfer coefficient of a fermentation system in a bubble colum

ISSN:0006-3592    

DOI:10.1002/bit.260280904

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

年代:1986

数据来源: WILEY

摘要:

AbstractTwo instruments were developed to mechanize the handling of anaerobic microorganisms for microbial mutant isolation. The instruments automatically dispense liquid or agar medium to large and small 96‐well platesand petridishes. Protocols were developed for inoculating different microorganisms, and calibration curves of number of areas or wells inoculated versus cell concentration were prepared for bacteria, yeast and fungi (spores). Experiments with yeast auxotrophic mutants and fungal spores showed that microbe inoculation follows Poisson statistics in distributing a single microorganism per inoculation point. The isolation and identification ofYarrowia lipolyticaauxotrophic, morphological, and temperature‐sensitive or tolerant mutants demonstrated the use of the instruments for microbial screen

ISSN:0006-3592    

DOI:10.1002/bit.260280905

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

年代:1986

数据来源: WILEY

摘要:

AbstractThermostable lipase fromThermomyces lanuginosuswas immobilized in untreated microporous membranes. Melted tallow pumped through the membrane did not wash the enzyme out. From 0.4 to 0.9% of the soluble activity remained after immobilization with half‐lives of 1–2 months or more at 50°C. Membranes can be acid/base washed and reloaded with enzyme with no adverse effects. Buffer was required for a long half‐life, and recycling the buffer improved the mass transfer of glycerol out of the immobilized lipase reactor. Immobilized activity was unaffected when the pH of the aqueous product changed from 5.5

ISSN:0006-3592    

DOI:10.1002/bit.260280906

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe fundamental problem of dynamic modeling of continuous culture systems for process control and optimization is addressed. Forcing a system to bifurcation via feedback control is a very promising method for model discrimination and identification. Dynamic information is obtained by using this technique, the dynamic behavior of the chemostat as predicted by unstructured models, the model with delay, and a structured model has been analyzed. The method exposes significant differences in the nonlinear dynamic structure of the various models and can be implemented to discriminate between various possible models for a continuous culture system.

ISSN:0006-3592    

DOI:10.1002/bit.260280907

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe Pronounced differences in performance of a strain ofClostridium acetobutylicumATCC 824 were analyzed by the method of systems analysis. The mechanism for cellular transport of substrate (glucose), solvents, and acids was studied and mathematically formulated. The systems analysis approach in the treatment of data from culture experiments pointed out the cell membrane malfunction indicated by its altered permeability and reflected in the altered number of active sugar transport sites. Experimental results obtained from the study of the cell uptake of 3‐0‐methyl glucose (0.7mM) by the “normal culture” and the “retarded culture” confirmed the theoretical predictions regarding a slower transport in the retarded culture. The initial uptake rate and the accumulation coefficient of the sugar in the normal culture were 15.0 and 4.1 times higher, respectively, than those for the retardedculture. Adjustment of the culture pH resulted in further increases in these parameters by factors of 3.0 and 3.5, r

ISSN:0006-3592    

DOI:10.1002/bit.260280908

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

年代:1986

数据来源: WILEY

摘要:

AbstractA substrate control system based upon dialysis culture techniques has been developed. In fermentations ofEscherichia coliwhere phosphate or sulfate concentrations were controlled, the relation between the apparent specific growth rate, μ, and the phosphate concentration followed Monod kinetics, while the relation between μ and sulfate showed a sharp optimun. The pH of fermentations ofE. coliwas controlled by dialysis culture techniques without the fluctuations in pH associated with control by direct addition of acid or bas

ISSN:0006-3592    

DOI:10.1002/bit.260280909

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

年代:1986

数据来源: WILEY

摘要:

AbstractImmobilized cells of aCitrobacterspecies scavenge cadmium with high efficiency from challenge flows containing Cd2+. Metal uptake by the cells in mediated by a cellbound phosphatase which liberates inorganic phosphate from an organic phosphate to precipitate cadmium as cell‐bound metal phosphate. Hitherto glycerol 2‐phosphate has served as the phosphate donor, but for an economic large scale process an inexpensive and readily available phosphate donor is required and the use of alkyl phosphates was investigated. This was limited due to interference by the alcohol simultaneously liberated. An alternative, pulsed process is described whereby alkyl phosphate‐supplemented main pulses interspersed with short alkyl phosphate‐free “recovery” pulses greatly reduced the requirement for glycerol 2‐phosphate. Wider aspects of phosphate donor utilization were also investigated to compare this strain ofCitrobacterwith a strain previously reported to accumulate lead bu

ISSN:0006-3592    

DOI:10.1002/bit.260280910

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

年代:1986

数据来源: WILEY

摘要:

AbstractLytic enzyme systems with the ability to break whole cells of yeast are a mixture of several enzymes and virtually all contain β(1–3)glucanases and some protease. It appears that the presence of these two enzyme activities is necessary to break the two layers of the rigid cell wall. The enzyme system ofCytophagaNCIB 9497 has a high activity towards the walls of yeast and also of bacteria. This article describes the production of this extracellular lytic enzyme system in batch and continuous culture—it was found to be inducible. The synthesis and regulation of the two main constituent enzymes, β(1–3)glucanase and protease, have been investigated. The synthesis of β(1–3)glucanase is regulated by bothinduction (by an unknown inducer) and catabolite repression. Highβ(1–3)glucanase activities were obtained in continuous culture at low dilution rates over a narrow range (0.05–0.10 h−1), and there is evidence of the presence of more than one glucanase enzyme. Proteolytic activity appears subject to catabolite repression and made up of the activities of more than one protease enzyme. Productivity and enzyme concentration were increased several fold in continuous culture when compared

ISSN:0006-3592    

DOI:10.1002/bit.260280911

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

年代:1986

数据来源: WILEY