Enzymatic Bioreactor

Nowadays, studies of direct electrochemistry of redox proteins at the electrodesolution interface have held more and more scientists interest. Those studies are a convenient and informative means for understanding the kinetics and thermodynamics of biological redox processes. And they may provide a model for the study of the mechanism of electron transfer between enzymes in biological systems, and establish a foundation for fabricating new kinds of biosensors or enzymatic bioreactors. 

Enzymatic bioreactor Immobilized enzyme biosensor Immobilized enzyme reactor Immobilized microfluidic enzyme reactor (IMER) Membrane reactor... 

Hemoperfusion circulates blood directly over sorbents, such as charcoal or anion exchange resins, or other more complex biochemical reactors, including immobilized enzymatic bioreactors, which allows the chemical processing of specific biologic products. This technique is limited by the loss of other useful substances and can cause complications, such as bleeding when there is an excessive removal of coagulation factors and platelets. To minimize these losses and improve biocompatibility, sorbents can be coated with cellulose to avoid direct contact with blood or plasma, although this in turn reduces the effectiveness of the sorbents. 

Another example was done by Opitz et al. They utilized P4HB scaffolds to produce viable ovine blood vessels, and then implanted the blood vessels in the systemic circulation of sheep. Enzymatically derived vascular smooth muscle cells (vSMC) were seeded on the scaffolds both under pulsatile flow and static conditions. Mechanical properties of bioreactor-cultured blood vessels which were obtained from tissue engineering approached those of native aorta. 

There have been many papers reporting studies on the influence of structure and conditions of the medium. Specifically, the kinetic behavior of enzymatic reactions in two-phase media was probed [7,25,27,63]. The reaction localization and the interaction between mass transfer and metabolism in compartmentalized media are interesting phenomena. Their study in the laboratory are useful for optimizing the operating conditions of bioreactors in a preparative scale. In addition, they also help to understand better the behavior of enzymatic systems in vivo. 

The approach presented here can help us better understand the behavior of some enzymatic systems in vivo. It can be useful for optimizing the operating conditions of bioreactors containing chemical species with amphiphilic properties. 

Fig. 11. Concentration profiles inside an SMB bioreactor. Dextrin (open square) was introduced in the reactor and enzymatically converted into maltose (filled circle), which was separated due to differences in the retention on the stationary phase. (Reprinted with permission from [177])... 

Several application methods are available for enzymatic reduction and precipitation of uranium. These include bioreactors, placement of the microorganisms on solid substrates for filtration, or placement in groundwater to create precipitation zones through which the contaminated groundwater migrates. 

More recently, enzymatic carboligation in a solid/gas bioreactor was demonstrated to be possible [55] in a model system based on the condensation of two propanal molecules to produce of propioin using thiamine diphosphate-dependent... 

In this chapter we provide the fundamental concepts of chemical and biochemical kinetics that are important for understanding the mechanisms of bioreactions and also for the design and operation of bioreactors. First, we shall discuss general chemical kinetics in a homogeneous phase and then apply its principles to enzymatic reactions in homogeneous and heterogeneous systems. 

Enzyme kinetics deals with the rate of enzyme reaction and how it is affected by various chemical and physical conditions. Kinetic studies of enzymatic reactions provide information about the basic mechanism of the enzyme reaction and other parameters that characterize the properties of the enzyme. The rate equations developed from the kinetic studies can be applied in calculating reaction time, yields, and optimum economic condition, which are important in the design of an effective bioreactor. 

FIG. 21 Schematic diagram for the production of L-malic acid from fumaric acid using a six-compartment (Zi-Z6) ED stack composed of anionic (a) and cationic (c) membranes, as extracted from Sridhar (1987). As ammonium fumarate is formed, it is enzymatically converted into ammonium malate in an external bioreactor (R). The combined system is also provided with a series of storage tanks for the acidic cathode-(Dl) and anode-(D6) rinsing solutions, raw materials (D2), ammonium fumarate (D3), ammonium malate (D4), and final product (D5). 

On the other hand, membranes are frequently employed in combination with a bioreactor, for instance, in enzymatic pharmaceutical processes. An example... 

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. 

---