Time course of production

Initial scale-up of microbial biotransformation is conveniently run with multiple flasks without extensive reaction optimization. A typical flask fermentation is performed at 28 °C, 250 rpm with 100 mL culture in a 500 mL Erlenmeyer flask, although other settings will work fine too. Three parameters need to be investigated before scale-up the time for adding the substrate, the optimal substrate concentration and the time course of product formation. Optimization of other factors, such as medium composition and pH, growing cells versus resting cells [74], is helpful, if the timeline allows and if there is a sufficient amount of the substrate to support the screening. 

Figure C1.1.2 Time course of product generation for typical enzyme-catalyzed reaction. Product concentration is shown to asymptotically approach its equilibrium value (horizontal dashed line). The diagonal dashed line illustrates the portion of the curve used to calculate initial velocity.

Time course of product of PBN adduct Solvent used in extraction ESR parameters (G) Nature of trapped radical (R )... 

Figure 9.11 Time course of production of octopamine with varying DBH concentrations 0.01 and 0.02 mg/mL for line A (A) and line B (O), respectively. Lines represent the least-squares fits of the initial data (From Feilchenfeld et al., 1982.)...

Figure 17.4 (a) Time course of product concentration in UF-membrane bioreactor at various substrate concentration (benzonitrile in 50mM sodium phosphate buffer, pFI 7.0). Cell load lOrngocw, temperature 10°C, flow-rate 12mlh. ... 

Action of ACTH. ACTH given in injections to rats decreases adrenal lipids and Choi esters but increases phosphatides and arachidonic acid S, Bovine adrenal slices use more added Choi but not P in the presence of ACTh8. The conclusion that a pool of 21-desoxypregnanes is released by ACTH for hydroxylatlon is questionable in the absence of data on the time course of production of steroids. 

Fig. (1). Time course of production of monorden (94) in Q6/2 medium (150 ml shake flasks) by strain P 0297.

Figure 6. Time course of production of (%) cell wall nigeran and (O) exocellular nigeran protein complex by A. awamori on incomplete medium. After growth on complete medium, washed cells were transferred to medium lacking nitrogen source (16). Aliquots of the culture were withdrawn periodically and cells were separated by filtration. The nigeran-protein complex was isolated from the filtrate by centrifugation at 30,000 Xg CL d washed repeatedly with water.

Figure 1. Time course of production of elsinan. Five liter medium containing sucrose was fermented with airation, 5-6.5 L/min and agitation, 300 rpm, at 24°C elsinan (O) dry cell (—A--) sucrose (— X —) pH reducing...

Time-course The time-course of production of heparin-induced antibodies has been studied in 435 patients receiving heparin thromboprophylaxis [76 ]. Antibodies formed in 56%, and in over 90% of cases they appeared at 4-14 days. After reaching maximum reactivity by days 10-12, the antibody titers fell, despite heparin continuation, even in two patients with HIT. Individual IgG, IgA, and IgM classes had identical times of onset (median day 6). Most of the antibody-positive patients (59%) developed all three immunoglobulin classes only 11% lacked an IgG response, and all three immunoglobulins usually increased simultaneously. 

Figure 5.3 Simulation of the time course of product formation (enzyme bound and free) under the condition when the dissociation of product from the enzyme complex is rate limiting. Diagrams (a) and (b) show the approach to the steady state on different time scales and (c) shows the formation of the enzyme product complex. The intercept 77 in diagram (a) can be used to calculate the concentration of active sites according to equation (5.1.23).

Measurement of Components of Mixtures. The problem of measurement of the individual components of a mixture confronts anyone who works with organisms that form several antibacterial substances. Interest may center in only one component, and its time course of production may be of considerable importance. What, then, are the procedures that have been used to solve the problem ... 

Abe s group (Abe, 1971 Abe et al, 1970) isolated L-leucyl-D-proline lactam and L-phenylalanyl-D- and L-proline lactam from cultures in which ergokryptine and ergotamine, respectively, were the major peptide alkaloids. The time course of production of the lactams was consistent with their involvement in peptide alkaloid biosynthesis (Abe et al, 1970). The role of the lactams as precursors of the peptide alkaloids was tested by carrying out incubations with the tritium-labeled lactams. Incorporation of L-leucyl-D- and -L-proline lactam into ergokryptine plus ergokryptinine was 0.06-1.45%, and incorporation of L-phenylalanine-D- and -L-proline lactam... 

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