Size methods solubilization

Although the proposed theory has been used effectively in several practical applications, no experimental proof has been given that the oil solubilization rate is a function of surfactant aggregate size. In view of the importance of solubilization and the existence of practical methods of measuring and controlling surfactant aggregate size, we decided to correlate the solubilization rate with micellar properties for some anionic and nonionic surfactants. 

Blanch and coworkers [145] investigated in detail the solubilization properties of a-chymotrypsin and alcohol dehydrogenase (ADH) in RMs prepared by the above three techniques. Protein solubilization in RMs greatly depends on the method used for protein addition as well as on the size of the protein and of the RM. For the dry addition method protein solubilization is strongly dependent on micelle size whereas for the injection method it is less dependent. For smaller proteins like a-chymotrypsin (diameter of 44 A), maximum solubilization occurred when the micelle diameter was 50 - 60 A. For larger proteins like ADH... 

For the injection method, where a saturated protein solution is added directly to the surfactant-containing organic phase, the RMs are forced to form around the proteins already present in the solution. Thus, protein solubilization is not strongly dependent on micelle size in this technique. 

The phase transfer method of protein solubihzation is fundamentally different from the other two methods. In this method, there are two bulk phases (aqueous and organic) which are brought to equihbrium. Under certain conditions, the protein molecules are transferred from the aqueous phase to the surfactant-containing organic phase. Unhke the dry-addition and injection methods, it is difficult to obtain a value for the maximum solubihzation using the phase-transfer method. Moreover, since this method is mainly used for protein extraction, it is desirable to use aqueous phase protein concentrations consistent with those in a typical fermentation broth. For the phase-transfer method, pH of the aqueous phase, the size and isoelectric point of the protein, and the surfactant type were shown to have a significant effect on protein solubilization [145]. 

Most monomers polymerizing by the radical mechanism are almost insoluble in water. Intensive stirring of a mixture of such a monomer with water produces an emulsion which remains stable, however, only in the presence of a surface active compound (tenside), e. g. soap. By the addition of a water-soluble initiator to this emulsion, the monomer polymerizes at a rate several times higher than would be observed by any other radical method with an initiator of equal efficiency. At the same time, a higher polymer with a narrower molecular mass distribution is formed. At the initial stages of the reaction, the monomer is present as three types of particle in tenside-stabilized monomer droplets of diameter 10-3 to 10 4cm (about 1012 such droplets are present in 1 cm3 of emulsion of average concentration) in solubilized micelles about 10 nm in size and concentration 1018 cm 3 and in the growing, emulsifier-stabilized monomer—polymer particles 50-100 nm in size. This situation is illustrated schematically in Fig. 14(a). 

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