The specific growth rate is one of the most important process variables characterizing the state of microorganisms during fermentations mainly because the biosynthesis of many products of interest is often related with the values assumed by this parameter. In the particular case of the fed-batch operation of Escherichia coli for the production of recombinant proteins, it is important to maintai...

In this paper, the metaheuristics algorithm Cuckoo Search (CS), is adapted and applied for a model parameter identification of an E. coli fed-batch cultivation process. The dynamics of bacteria growth and substrate (glucose) utilization is described by a system of ordinary nonlinear differential equations. Using real experimental data set from an E. coli MC4110 fed-batch cultivation process a p...

M athematical model–based simulations of actual bioreactor runs suggest how process variables such as substrate and product concentrations change and how nutrient feeding should be “tuned” with respect to time, pattern, concentration, and composition to elicit a desired response. Insights gained from modeling can guide us in the adjustment of a process, reducing the number of characterization r...

In this paper, a fed-batch cultivation process in recombinant Escherichia coli BL21(DE3) bacteria, for the production of human soluble catechol-O-methyltransferase (hSCOMT), is presented. For the first time, a straightforward model is applied in a recombinant hSCOMT expression system and distinguishes an initial cell growth phase from a protein production phase upon induction. Specifically, the...

Increase in air or oxygen pressure in microbial cell cultures can cause oxidative stress and consequently affect cell physiology and morphology. The behaviour of Saccharomyces cerevisiae grown under hyperbaric atmospheres of air and pure oxygen was studied. A limit of 1.0 MPa for the air pressure increase (i.e. 0.21 MPa of oxygen partial pressure) in a fed-batch culture of S. cerevisiae was est...

A novel strategy to increase protein expression yield is unintended induction of expression in complex media, called auto-induction. This method can be used to express proteins under control of the lac promoter without any need to monitor bacterial growth pattern, and addition of specific expression inducers such as Isopropyl β-D-1-thiogalactopyranoside (IPTG) at proper time. In the present stu...

In the paper a genetic algorithm for feed rate profiles synthesis is proposed. An E. coli fed-batch fermentation process is considered. The feed rate profiles based on three different lengths of chromosomes are synthesized. A satisfactory result for the fermentation system due to economical effect and process effectiveness is achieved.

The relationship between lipid content and tolerance to freezing at -50 degrees C was studied in Saccharomyces cerevisiae grown under batch or fed-batch mode and various aeration and temperature conditions. A higher free-sterol-to-phospholipid ratio as well as higher free sterol and phospholipid contents correlated with the superior cryoresistance in dough or in water of the fed-batch-grown com...

In this paper we review recent advances on the practice and theory of process control with particular emphasis to the operation of bioreactors. We present in detail a case-study on the modelling, model-based identification and adaptive control of fed-batch baker's yeast fermentation. 1. Practice and Theory of Process Control An Overview 1.

Introduction Single-Use Bioreactors are now commonly used for Process Development activities, as seeding bioreactors or to produce Drug Substances. The advantages of this equipment have been well demonstrated over the last years on batch/fed-batch processes. Continuous processes were widely applied in the past to increase the overall productivity of small bioreactors or for sensitive molecule p...