Sterilization kinetic model

Two continuous stirred-tank fermenters are connected in series, the first having an operational volume of 100 1 and that of the second being 50 1. The feed to the first fermenter is sterile and contains 5000 mg/1 of substrate, being delivered to the fermenter at 18 1/h. If the microbial growth can be described by the Monod kinetic model with /x, = 0.25 h l and Ks = 120 mg/l, calculate the steady-state substrate concentration in the second vessel. What would happen if the flow were from the 50 I fermenter to the 100 1 fermenter ... 

Phenomenological Kinetic Model of Non-Thermal Plasma Sterilization of Air Streams... 

In the framework of the aforementioned kinetic model of plasma sterilization, the following formula describes the rate of inactivation of airborne micro-organisms inside a DBD from the combination of effects of ozone, hydroxyl, and UV radiation ... 

Sterilization of Media First-order kinetics may be assumed for heat destruction of living matter, and this leads to a linear relationship when logarithm of the fraction surviving is plotted against time. However, nonlogarithmic kinetics of death are quite often found for bacterial spores. One model for such behavior assumes inactivation of spores via a sensitive intermediate state by the mechanism ... 

Dry heat destruction of bacterial endotoxins is complex and poorly understood much of the research data is contradictory [2]. Most experimental evidence has shown that destruction follows second order chemical kinetics with a high initial rate of decrease of endotoxin followed by a much slower terminal rate. These second-order models give a better estimate of the kinetics of endotoxin destruction at temperatures above 250 C than in the 170 to 250 C temperature band. Impure endotoxin may account for these anomalies. There is practically no endotoxin destruction at temperatures below 80 0, and D-values for dry heat sterilization temperatures of around I70°C are as high as 20 min [2], These observations are in agreement with published c-values of around 40 C for endotoxin destruction. Evidence of endotoxin destruction in practical situations is usually taken from empirical observation because of the uncertainty over its theoretical basis. 

A very useful application of dummy or indicator variable regression is in modeling regression functions that are nonlinear. For example, in steam sterilization death kinetic calculations, the thermal death curve for bacterial spores often looks sigmoidal (Figure 9.9). 

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