A Computer‐aided noninterfering on‐line technique for monitoring oxygen‐transfer characteristics during fermentation processes

Abstract

The role of computers in the monitoring and control of fermentation processes has increased steadfastly. The ultimate utility of the machines will not depend on the availability of online sensors but also on the availability of techniques that combine direct measurements, leading towards estimates of variable closely related to the microbial process or its control. In this article, a methodology for on-line and noninterfering evaluation of the volumetric mass-transfer coefficient K(l)a is developed. A detailed presentation of the procedure, called "the static method," is given. Its feasibility is proved through implementation of the method on an antibiotic fermentation process. These experiments indicate that operator actions meant to modify the oxygen-transfer conditions can be checked on-line. The quantitative value of the static method is ascertained by comparing the experimental results with K(l)a estimates obtained with the "gassing-out" method. A sensitivity analysis was carried out, revealing the need for temperature and pressure corrections and showing that the precision of the oxygen analyzer determines the precision of the static method.

Scaling-up vaccine production: implementation aspects of a biomass growth observer and controller

“…As a result the observed biomass concentrations were closer to the samples when the dynamic OUR calculation was used (Eqs. [8][9][10].…”

“…2) and using online reconstruction (Eqs. [8][9]. Each of these signals was used as input for the Extended Kalman Filter [17] to observe biomass and specific growth rate and finally to predict biomass concentrations (Eq.…”

“…Often the computation of OUR using off-gas measurements is based on a steady-state assumption (for example in [5][6][7][8][9][10][11][12]):…”

Advanced control of glutathione fermentation process

“…Therefore an alternative process model which does not require any off-line data was developed using overall oxygen consumption rate instead of overall consumption rate of carbon source. This model may be written as Overall oxygen consumption rate = oxygen consumption rate for sugar consumption + oxygen consumption rate for ethanol consumption This relation can be formulated in the following equation: (11) where YoZis = oxygen required for sugar oxidation (mol YoliE = oxygen required for ethanol oxidation In Eq. (11), if S F , -d(VE)/dt, YozIs, and YoziE were assumed to be constant during fed-batch operation, sugar feed rate F could be easily calculated from total oxygen uptake rate Qo, X V .…”

Determination of the overall volumetric mass transfer coefficient kLa, by a temperature dependent change of gas solubility

“…The steady-state method (Spriet et al, 1982) requires respiring cells in the bioreactor. The dynamic methods require oxygen removal either by a sodium sulphite solution (Cooper et al, 1944), by respiring cells (Bandyopadhyay et ai., 1967) or by sparging with an inert gas (Yoshida et al,, 1980).…”