Protein reaction, removing impurities

Figure 5. Scheme for removing impurities from protein substrate by hydrolysis, purification, and resynthesis via the plastein reaction (i)... 

For SDS, the reaction proceeded to a reproducible end point rapidly —viz., 1 to 2 minutes—when nonionic surface active impurities such as parent dodecyl alcohol, DOH, were removed by ethyl ether extractions. This impurity effect was verified by adding traces of alkyl alcohol—viz., 1 X 10 9 mole per liter—to purified SDS, whereupon the penetration reaction rate was halved. A possible explanation for this behavior is that formation of an SDS-DOH interfacial complex reduced the SDS activity in the interface and consequently its rate of reaction with the protein monolayer. The reasons for the somewhat slower rate of reaction of Cetab with the protein film are more obscure. The reaction rate did not increase after extracting the detergent repeatedly. Two possible reasons for the time dependence in this case may have been that (1) the ether extraction method was not effective in removing surface active impurities, or (2) because of the greater bulk of the Cetab hydrocarbon chain, Ci6 vs. Ci2 for SDS, more time was required for diffusion and appropriate orientation before complex formation. 

Removal of dissolved inorganic impurities from methanol Is of Interest from the point of view of utilization of methanol as an alternative to conventional fuels. Reports show that the corrosion rate of metal alloys used for turbines and fuel transportation is greater in methanol than in water in the presence of traces of chlorine and sodium ions ( , 10). Further, ion complexes in trace quantities have been observed in methanol and there is concern that they could alter the reaction kinetics for processes which use methanol as a feedstock or reaction medium (11). Methanol that Is used as a feedstock In the production of single cell protein could be sterilized as well as purified of heavy metals by reverse osmosis which can be integrated in the design of these processes. 

A Tokyo group [46] was the first to propose a combined process of enzymatic protein hydrolysis and resynthesis for producing a product with improved sensory properties and modified amino acid composition. An enzymatic reaction was used also for the removal of bound impurities [108,109], for debittering of hydrolysates [47,110], and for decolorization of proteins of particular origin [111]. 

The preparation of cotton before it can be woven and subjected to downstream processes such as dyeing involves, amongst other processes, the removal of impurities from the raw cotton in particular, waxes, fats, pectins and proteins. There are a number of environmentally-friendly bioseparation processes that can perform this purification duty, without leading to effluents that do not biodegrade. These can be based upon enzymatic reactions, that are, as pointed out by Yachmenev et al. (2(X)4) rather slow. The aim of their research was to show that the process could be speeded up using active PI methods. 

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