ISSN:
1432-0614
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Summary Maximization of microbial two-step conversion of 9α-fluorohydrocortisone to Δ1-dehydro-16α-hydroxy-9α-fluorohydrocortisone (triamcinolone) in a mixed culture of two microorganisms, Arthrobacter simplex and Streptomyces roseochromogenus, was attempted by a digital simulation, to optimize an operational parameter, pH, during batch cultivation. A mathematical model of the steroid transformation in the mixed culture was constructed with nine differential equations. The kinetic parameters other than the Michaelis-Menten constants in the mathematical model varied with pH of the culture medium. The mathematical model facilitated the simulation of the effect of pH on steroid conversion in the mixed culture. A modified Simplex method of direct search was applied to optimize the switching time and the combination of pH values in the batch culture with several step-changes of pH. Varied-pH processes showed much higher conversion yields than the constant pH process. A process of 3-phase pH change is expected to be advantageous in practical operation because of its lower susceptibility to pH perturbation, though the yield is almost the same as that of the 2-phase process.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00518048
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