Free enzyme batch reactor

Enzymatic Reactors Adding free enzyme to a batch reactor is practical only when the value of the enzyme is relatively low. With expensive enzymes, reuse by retaining the enzyme with some type of support makes great economic sense. As some activity is usually lost in tethering the enzyme and the additional operations cost money, stabihty is very important. However, many enzymes are stabilized by immobilization thus, many reuses may be possible. 

The inhibition analyses were examined differently for free lipase in a batch and immobilised lipase in membrane reactor system. Figure 5.14 shows the kinetics plot for substrate inhibition of the free lipase in the batch system, where [5] is the concentration of (S)-ibuprofen ester in isooctane, and v0 is the initial reaction rate for (S)-ester conversion. The data for immobilised lipase are shown in Figure 5.15 that is, the kinetics plot for substrate inhibition for immobilised lipase in the EMR system. The Hanes-Woolf plots in both systems show similar trends for substrate inhibition. The graphical presentation of rate curves for immobilised lipase shows higher values compared with free enzymes. The value for the... 

A commercial pectinase, immobilised on appropriately functionalised y-alumina spheres, was loaded in a packed bed reactor and employed to depolymerise the pectin contained in a model solution and in the apple juice. The activity of the immobilized enzyme was tested in several batch reactions and compared with the one of the free enzyme. A successful apple juice depectinisation was obtained using the pectinase immobilised system. In addition, an endopolygalacturonase from Kluyveromyces marxianus, previously purified in a single-step process with coreshell microspheres specifically prepared, was immobilised on the same active support and the efficiency of the resulting catalyst was tested. 

The patent described a method for the removal of thiophenic compounds from fossil fuels, in which the reacting media might contain organic solvents. Additionally, the biocatalyst may be contacted with the fuel directly either as free enzyme or in its immobilized form. The process could, therefore, be performed either in a batch reactor or in a semi-continuous or continuous manner. Further, it may be performed either as a stand... 

A substrate solution of 0.1 kmol m is reacted in a stirred-batch reactor using the free enzyme. Determine the initial reaction rate and the conversion of the substrate after 10 min. 

Free enzyme versus immobilized enzyme can influence the yield of lOS, additionally an immobilized system would be favorable economically as the biocatalyst can be reused, enables continuous production and the end product is free of contamination. Kim et al. [275] intended to make a comparison between the reaction kinetics of free and immobilized endo-inulinases in a batch reactor however significant differences were observed in the reaction behavior and product composition due to the form of enzyme used and the initial concentration of substrate. Yun et al. [276] investigated the effect of inulin concentration on the production of lOS by free and immobilized endo-inulinase from Pseudomonas sp. Their findings corroborate those of Kim et al. [275] whereby different products are formed depending on the form of enzyme a soluble enzyme yielded inulobiose and DP3 products, whereby the immobilized form predominantly produced inulobiose. As the concentration of inulin increased the yield of lOS did not increase in the soluble system and in the immobilized the yield remained the same. Although the enzyme was derived from Pseudomonas the immobilized form required a differ-... 

We have reasoned that a novel approach to prolong the production phase of secondary metabolites should be based on an attempt to prevent or retard the process of lja vivo Inactivation of the enzymes (synthetases) catalyzing their formation In fermentations. Such an attempt would require an understanding of the chemical nature of the Inactivation. This knowledge could be subsequently translated Into process development and control In actual fermentations, which, for the most part, are carried out In batch reactors. If the object of the fermentation Is the recovery of the enzymes for further use In a cell-free system or the acquisition of active whole cells for repeated use In a fixed bed-type bloreactor, the prevention or retardation of the Inactivation process would ensure both an adequate margin of time for primary harvesting and a longer half-life of the activity for the blo-catalysts In the cells. 

FIGURE 5.1 Typical schematic diagram of a batch reactor for the hydrolysis of chitosan using free enzyme. (From Kim, S.K. and Rajapakse, N., Carbohydr. Polym., 62, 357, 2005. With permission)... 

It is clear, however, that the operation of the SSF process in continuous reactors led to a worse performance than the one obtained in the batch experiments, with the same enzyme and yeast concentrations in the reactor and similar total reducing sugar concentration (initial, in the batch run and in the feed, for the continuous run). The concentration of free glucose in the effluent was lower than 1 g/1 for all the tested flow rates, except for the two... 

To select the most suitable solvent for a desired reaction, screening of various solvents is usually necessary, since the prediction of the best solvents by the simulation is still difficult. The screening has to be condurted to optimize the reaction conditions with respect to (1) the type and scale of the reaction, (2) the stability of the biocatalyst, (3) the hydrophobicity of the solvents, (4) the solubilities of the substrate and product, (5) the recovery of the product and enzyme, (6) environmental and safety concerns, and (7) the cost of the biocatalyst, substrate, and product. For example, to conduct a dehydration reaction using hydrolytic enzyme, a water-free nonaqueous solvent must be selected instead of water. On the other hand, the level of the dehydration should not be too much, as noted previously, to take away the water from enzyme necessary for its activity. Supercritical CO is better to be used in relatively large scale using a flow reactor than using in the very small-scale batch reaction because product recovery in the small-scale reaction in batch CO reactor needs extraction with organic solvents. 

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