OL2 (mmole CO2/ g biomass h)
<*3 (mmole CO2/ L h)
are not considered due to the complex nature of the phenomenon, and unavailability of the experimental data.
A typical inhibition term that includes hydrogen ion concentration [H+] is introduced into the specific growth rate expression. It has been found that the [H+]-dependent term in the rectangular parentheses in Eq. 2.48. The values of Ki and K2 are chosen to be in the range of their typical values in the literature [426, 545].
The influence of temperature on the specific growth rate of a microorganism shows an increasing tendency with an increase in temperature up to a certain value which is microorganism specific and a rapid decrease is observed beyond this value. This decrease might be treated as a death rate . These effects are reflected in the temperature-dependent term in Eq. 2.48 with kg and Eg being the pre-exponential constant and activation energy for cell growth, and k¿ and E¿ being the pre-exponential constant and activation energy for cell death, respectively. Typical values for these parameters were taken from the literature . An adjustment has been made so that an increase in temperature enhanced the biomass formation up to 35°C.
The production of penicillin is described by non-growth associated product formation kinetics. The hydrolysis of penicillin is also included in the rate expression  for completeness.
where, ep is the specific penicillin production rate defined
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