摘要:

AbstractCurrent methodology now makes it possible to establish in culture a variety of mammalian cells which perform organ‐specific functions during serial propagation for periods of months or years. This report describes the results of experiments with animal and human cells that produce growth hormone, adrenocortical steroid hormones, thyrocalcitonin, and parathyroid hormone. Within the next decade it should be possible to use cell culture methods for manufacturing purposes to produce hormones and other valuable cellular products which are difficult to obtain in other ways. At first it may be necessary to use neoplastic cells for this purpose; but evidence is accumulating to suggest that it may eventually be possible to establish in culture normal, functional animal and human cell

ISSN:0006-3592    

DOI:10.1002/bit.260110202

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

年代:1969

数据来源: WILEY

摘要:

AbstractPure bacterial cultures can be flocculated by a variety of chemical flocculants. Flocculation of bacteria will assist in their recovery, especially where the cells themselves are of interest, as in microbial protein production. Studies with several genera of bacteria indicate that the mechanism of flocculation is highly complex. Such interacting variables as temperature, ionic environment, physiological age, flocculant, bacterial genus, and surface shear have been observed. Jar test experiments with washed cells indicate that many of the variables are related to the release by the cell of proteins, nucleic acids, or polysaccharides. When released, these polymers may increase the required dosage of flocculant for recovery as in the case ofE. coli, or the dosage may decrease as it does forLactobacillus.

ISSN:0006-3592    

DOI:10.1002/bit.260110203

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

年代:1969

数据来源: WILEY

摘要:

AbstractA theoretical study was made on the dynamic behavior of a single‐vessel continuous fermentation subject to a growth inhibition at, high concentration of the rate limiting substrate. Phase plane plotting and stability analysis showed three steady states to exist; namely, a “washout”; state, a nontrivial stable state, and an unstable state. Whether the system attains a nontrivial steady state or is to be washed‐out depends upon the initial values of the cell and/or substrate concentration(s). Since this property is a characteristic feature of the present system, an experimental procedure was suggested to insure a stable operation in p

ISSN:0006-3592    

DOI:10.1002/bit.260110204

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

年代:1969

数据来源: WILEY

摘要:

AbstractThree different established strains of mammalian cells were grown in chemically defined medium in large cultures. The degree of proliferation of cells of an established strain from human skin in large stationary cultures was significantly greater in the presence of methylcellulose (medium NCTC 135M) than in its absence (medium NCTC 135). The relatively fragile cells of a derivative of monkey kidney LLCMK2 strain were carried in large stationary cultures through 11 transfer generations during 152 days. The presence of methylcellulose was associated with higher cell population levels, proliferation rates, and cell viability. Cells of this strain utilized glucose at an extremely high rate; during two representative periods the rate averaged 1.2 mg/106cells/day in cultures on medium 135M and 1.9 mg in medium 135.In a 53‐day experiment with mouse fibroblast 2071‐L cells, the cells in suspension culture during the first 28 days went through the normal lag, logarithmic plateau, and initial decline phases in medium 135M, and then were transferred to large stationary cultures, where they proliferated for 7 days at uniformly high rates in both medium 135 and medium 135M. It appeared that cells of strain 2071‐L in such stationary cultures had no need for Methocel as a protective agent. Glucose utilization rates while these cells were carried in large stationary cultures averaged 2–4 times the rates while they were in suspension cultures: about 0.8 and 0.2 mg/106cells/day, repe

ISSN:0006-3592    

DOI:10.1002/bit.260110205

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

年代:1969

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260110206

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

年代:1969

数据来源: WILEY

摘要:

AbstractGrowth kinetics of heterogeneous populations of sewage origin were studied in completely mixed reactors of the once‐through type at a high concentration of incoming substrate, 3000 mg/l glucose, and in systems employing cell feedback or sludge recycle at an incoming substrate concentration of 1000 mg/1 glucose. The recycle flow rate employed was 25% of the incoming feed flow, and the concentration of cells in the recycle was maintained as closely as possible at 150% of the cell concentration in the reactor. Studies were made at various dilution rates. Throughout these studies, batch experiments using cells grown at the various dilution rates were made to determineksand μmvalues. As in previous studios using heterogeneous populations, the relationship between specific growth rates μ and substrate concentrationSwas represented better by the Monod equation than by any other which was tested. The growth “constants” μm,ks, andYwere found to fall in the same general range as those determined in previous studies in once‐through systems operated at 1000 mg/l glucose. It was observed that cell recycle, even at the relatively low concentration factor employed in these studies, greatly enhanced the flocculating and settling characteristics of

ISSN:0006-3592    

DOI:10.1002/bit.260110207

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

年代:1969

数据来源: WILEY

摘要:

AbstractContinuous saccharification of Solka Floc (cellulose pulp) in single and four‐vessel stirred‐tank reactor systems has been possible employing enzymes obtained directly from submerged fermentation ofTrichoderma virideQM 6a. Studies on the effect of modification of the solid substrate, enzyme stability, substrate concentration, and the influence of reducing sugar concentration on the rate of hydrolysis are reported. While susceptibility of substrate to digestion is not affected by heating alone, it is strikingly increased by heating plus grinding, or by grinding following heating. Batch and steady state continuous saccharification experiments have yielded more than 5% reducing sugar in the effluent with a dilution rate of 0.025 hr−1at 50°C, at a substrate level of 10%. An average glucose concentration of 3.4% has been obtained in the effluent of a continuous saccharification using 5% substrate at the same dilution rate and tempe

ISSN:0006-3592    

DOI:10.1002/bit.260110208

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

年代:1969

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260110209

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

年代:1969

数据来源: WILEY

ISSN:0006-3592    

DOI:10.1002/bit.260110201

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

年代:1969

数据来源: WILEY