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• 1
Electronic Resource
New York, NY [u.a.] : Wiley-Blackwell
Biotechnology and Bioengineering 9 (1967), S. 413-427
ISSN: 0006-3592
Keywords: Chemistry ; Biochemistry and Biotechnology
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The alcoholic fermentation of grape juice by a wine yeast was studied batchwise at pH 3.6 and 4.05 to develop kinetic equations relating cell concentration, N, to product concentration, P. In the exponential growth phase \documentclass{article}\pagestyle{empty}\begin{document}$$dP/dt + BP = A{\rm ln}N/\mu - C$$\end{document} where A, B, and C are constants, and μ is the specific growth rate. In the stationary phase, where the cell population is constant, \documentclass{article}\pagestyle{empty}\begin{document}$$dP/dt = B(P_m - P)$$\end{document} was found to apply. This equation, which incorporates a stoichiometric constant, Pm, predicted correctly the operation of a continuous fermentor at pH 3.6 and at 4.05. To study more fully the effect of alcohol concentration on yeast growth, a continuous fermentor was used in which the grape juice feed was supplemented with pure alcohol. At pH 3.6 the specific growth rate varied as, \documentclass{article}\pagestyle{empty}\begin{document}$$({\rm 1}/N)(dN/dt) = \mu _{{\rm max}} [{\rm 1} - 0.235(P - 2.6)]$$\end{document} There was no growth inhibition below an alcohol concentration of 2.6 g./100 cc., but inhibition was complete above 6.85 g./100 cc. This is a modified form of the relation suggested by Hinshelwood.1 The data suggest that growth in batch culture was limited not only by alcohol but also by some other factor, probably a nutritional deficiency.
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• 2
Electronic Resource
New York, NY [u.a.] : Wiley-Blackwell
Biotechnology and Bioengineering 11 (1969), S. 909-909
ISSN: 0006-3592
Keywords: Chemistry ; Biochemistry and Biotechnology
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
Type of Medium: Electronic Resource
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• 3
Electronic Resource
New York, NY [u.a.] : Wiley-Blackwell
Biotechnology and Bioengineering 15 (1973), S. 1159-1177
ISSN: 0006-3592
Keywords: Chemistry ; Biochemistry and Biotechnology
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
Notes: A simplified model of cell metabolism, consisting of a series of linked reversible enzymatic reactions dependent on the concentration of a single external substrate has been developed. The general mathematical solution for this system of reactions is presented. This general solution confirms the concept of a rate-limiting step, or “master reaction”, in biological systems as first proposed by Blackman. The maximum rate of such a process is determined by, and equal to, the maximum rate of the slowest forward reaction in the series.Of practical interest in modeling the growth rate of cells are three cases developed from the general model. The simplest special case results in the Monod equation when the maximum forward rate of one enzymatic reaction in the cell is much less than the maximum forward rate of any other enzymatic reactions.More realistic is the case where the maximum forward rates of more than one enzymatic reaction are slow. When two slow enzymatic reactions are separated from each other by any number of fast reactions that overall can be described by a large equilibrium constant, the Blackman form results: \documentclass{article}\pagestyle{empty}\begin{document}$$\mu = [S]/A, \rm{when} [S] 〈 A\mu_{\rm{max}}$$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$$\mu = \mu_{\rm{max}}, \rm{when} [S] \rm{〉} A\mu _{\rm{max}}$$\end{document}A third case is that in which two slow enzymatic steps are separated by an equilibrium constant that is not large. Unlike the Monod and Blackman forms, which contain only two arbitrary constants, this model contains three arbitrary constants: \documentclass{article}\pagestyle{empty}\begin{document}$$[S] = \mu A + \frac{{\mu B}} {{(\mu_{\rm{max}} - \mu)}}$$\end{document}The Monod and Blackman forms are special cases of this three constant form.In comparing equations with two arbitrary constants the Monod equation gave poorer fit of the data in most cases than the Blackman form. It is concluded that workers modeling the growth of microorganisms should give a t least as much consideration to the Blackman form as is given to the Monod equation.
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• 4
Electronic Resource
New York, NY [u.a.] : Wiley-Blackwell
Biotechnology and Bioengineering 11 (1969), S. 127-138
ISSN: 0006-3592
Keywords: Chemistry ; Biochemistry and Biotechnology
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Pure 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 of E. coli, or the dosage may decrease as it does for Lactobacillus.
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• 5
Electronic Resource
New York, NY [u.a.] : Wiley-Blackwell
Biotechnology and Bioengineering 19 (1977), S. 583-589
ISSN: 0006-3592
Keywords: Chemistry ; Biochemistry and Biotechnology
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
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• 6
Electronic Resource
New York, NY [u.a.] : Wiley-Blackwell
Journal of Applied Polymer Science 18 (1974), S. 3571-3579
ISSN: 0021-8995
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
Notes: Polycaprolactone is degraded by the mold P. pullulans in the presence of other nutrients. The weight loss from solid polymer films covered by a nutrient agar gel on which colonies are growing is used to establish comparative rates of degradation. There is substantial loss (16 mg/cm2 surface area) from a whole polymer of low (2,000) molecular weight in three weeks at 30°C. A high (30,000) molecular weight whole polymer degrades about 0.15 as much in the same time period. A fraction in the same range (38,000) but with a narrower molecular weight distribution shows no significant loss. This indicates that whole polymers of high molecular weight may lose only a portion of their distribution by microbial degradation in short-term tests. This hypothesis is tested by making mixtures of high (61,000) molecular weight with low (2,000) molecular weight polymer. Degradation is directly proportional to the low molecular weight content in these short-term tests with a single species of mold. Other workers have shown previously that in long-term, soil-burial tests, even a high (40,000) molecular weight polycaprolactone is essentially completely degraded after one year.
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• 7
Electronic Resource
New York, NY [u.a.] : Wiley-Blackwell
Biotechnology and Bioengineering 8 (1966), S. 71-84
ISSN: 0006-3592
Keywords: Chemistry ; Biochemistry and Biotechnology
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
Notes: A 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 discussed.
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• 8
Electronic Resource
[s.l.] : Nature Publishing Group
Nature 252 (1974), S. 572-574
ISSN: 1476-4687
Source: Nature Archives 1869 - 2009
Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
Notes: [Auszug] Table 1 Residence time as a function of radial distance for falling spheres Polymer solution 0.6%Polyhall 1.0%Polyox Radial distance from 0.52 1.85 1.17 1.85 bob surface (cm) 9 (s cm-1) 0.878 0.752 0.607 0.579 Bob rotational 8/1 Speed (r.p.m.) of Aluminium sphere A ...
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• 9
Electronic Resource
s.l. : American Chemical Society
Industrial & engineering chemistry 42 (1950), S. 1857-1861
ISSN: 1520-5045
Source: ACS Legacy Archives
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 10
Electronic Resource
s.l. : American Chemical Society
Industrial & engineering chemistry 48 (1956), S. 1540-1543
ISSN: 1520-5045
Source: ACS Legacy Archives
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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