Traditional bioreactors

Rhizosecretion is easy to scale up and very cost effective with respect to isolation and purification. However, the bioreactor systems used for hairy root cultures differ from those used for plant cell suspensions. Traditional bioreactor systems have recently been adapted for root culture, and this technology is now being taken to commercial scales. The most traditional system is the airlift bioreactor used for microorganisms or plant cells. This system is adapted for the culturing of roots in liquid medium. Mist culture systems have also been developed. For this technology, the volume of the culture medium is reduced and the concentration of the secreted therapeutic protein is increased. If the protein to be produced is known to be quite stable, then a less expensive hydroponic culture can be designed in a manner suitable for scale-up. 

In recent years, membrane bioreactors, bioreactors combined with membrane separation unit have established themselves as an alternative configuration for traditional bioreactors. The important advantages offered by membrane bioreactors are the several different types of membrane modules, membrane structures, materials commercially available. Membrane bioreactors seem particularly suited to carry out complex enzymatic/microbial reactions and/or to separate, in situ, the product in order to increase the reaction efficiency. The membrane bioreactor is a new generation of the biochemical/chemical reactors that offer a wide variety of applications for producing new chemical compounds, for treatment of wastewater, and so on. 

Fermenter Type of traditional bioreactor (involving either stirred or nonstirred tanks) in which cell fermentation takes place in continuous-culture fermenters, nutrients are continuously fed into the fermentation vessel so that cells can ferment indehnitely, whereas in batch fermenters, nutrients are added in batches. 

Non-stirred, aerated vessels are used in the process for traditional products such as wine, beer and cheese production. Most of the newly found bioprocesses require microbial growth in an aerated and agitated system. The percentage distribution of aerated and stirred vessels for bioreactor applications is shown in Table 6.1. The performances of various bioreactor systems are compared in Table 6.2. Since these processes are kinetically controlled, transport phenomena are of minor importance. 

Fluidization Regime. As for traditional fluidization applications, the fluidization regime—dispersed bubble, coalesced bubble, or slugging—in which a three-phase fluidized bioreactor operates depends strongly on the system parameters and operating conditions. Generally, desirable fluidization is considered to be characterized by stable operation with uniform phase holdups, typical of the dispersed bubble regime. It would be useful to be able to predict what conditions will produce such behavior. 

Harshbarger, D., Bautz, M., Davison, B. H., Scott, T. C., and Scott, C. D., Economic Assessment of Ethanol Production Comparing Traditional and Fluidized-Bed Bioreactors, Appl. Biochem. Biotechnol., 51/52 593 (1995)... 

Single-strand conformation polymorphism (SSCP) Wastewater bioreactors (including denitrifying and phosphate-removal system, Chinese traditional medicine wastewater treatment system, beer wastewater treatment system, fermentative biohydrogen producing system, and sulfate-reduction system) Microbial community structures, diversity and distribution in different wastewater treatment processes, and relationship between the structures and the status of processes [157]... 

Membrane bioreactors have been reviewed previously in every detail [3,4,7,8,18], There are two main types of membrane bioreactors (i) the system consists of a traditional stirred-tank reactor combined with a membrane separation unit (Figure 14.1) (ii) the membrane contains the immobilized biocatalysts such as enzymes, micro-organisms and antibodies and thus, acts as a support and a separation unit (Figure 14.2). The biocatalyst can be immobilized in or on the membrane by entrapment, gelification, physical adsorption, ionic binding, covalent binding or crosslinking [3, 7, 18]. Our attention will be primarily focused on the second case where the membrane acts as a support for biocatalyst and as a separation unit, in this study. The momentum and mass-transport process, in principle, are the same in both cases, namely when there is... 

Tissue engineering is a recent discipline that is closely related to cell therapy, but combines knowledge of molecular and cell biology with traditional concepts from biomaterials engineering, bioreactors, biomechanics, and controlled drug release, aiming at the development of new tissues. 

Parameters that are traditionally used to evaluate the metabolic activity of the cell population inside a hollow-fiber bioreactor include glucose consumption rate (rQLc) and oxygen consumption rate (rcu)- However, these parameters are highly dependent on variations in nutrient feed and metabolic products removal (Gramer et al., 1999). The use of a strategy to overfeed the ICS with nutrients results in a rapid increase in tglc- On the other hand, an increase in product titer and an improved metabolic... 

This has led to an increased interest in methods for the in vitro production of large quantities of mAbs. Submersed cultivation in bioreactors is one possibility. In contrast with traditional methods, this procedure uses large quantities of culture medium, increasing the scale of the process and making possible the production of virtually unlimited quantities of mAbs by a given hybridoma. 

Measurement and control of low-flow rates are a requirement in such applications as fuel cells, purging, bioreactors, leak testing, and controlling the reference gas flow in chromatographs or in plasma-emission spectrometers. The most traditional and least expensive low-flow sensor is the variable-area flowmeter. It has a high rangeability (10 1) and requires little pressure drop. Due to its relatively low accuracy, it is limited to purge and leak-detection applications. 

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