The production of enzymes by fermentation has been carried out for many years. Fermentation is usually carried out in stainless steel equipment i.e. mixing and blending tanks, and seed and main fermentators. Constant temperature, automatic foam and pH controllers and air purifiers are employed since the absence of foreign microorganisms is essential. Tap water is generally combined with the media ingredients and enzyme recovery begins as soon as fermentation is terminated. The medium is cooled and centrifuges are used to remove bacteria and large insolubles from the supernatant followed by filters to separate smaller particles. Enzyme is concentrated and removed from the filtrate by the addition of a precipitating agent. The precipitate is then further treated by additional filtering and drying etc. and is then standardized such as by using sodium chloride.
Proteases are enzymes which have been found to be particularly useful in industrial areas including cheese making, meat tenderizing, bread baking, beer haze elementation, digestive aid preparations, garment cleaning, pharmaceutical preparation and the like. Those proteases produced by cultivation can be used as food additives.
Characteristic of the protease enzyme broth is the formation of a suspension that does not settle. Upon centrifugation of a sample in a test tube, solids will be deposited in the lower 70% of the test tube and only the upper 30% of the tube will be clear supernatant solution.
One of the most difficult problems involving enzyme production is the isolation of the enzyme from its broth. Although many flocculating agents have been used for the precipitation of enzyme broths, most have suffered from some disability which renders the agent less attractive commercially. Examples of flocculants used commercially include epichlorohydrindimethylamine condensation products cross-linked with diethylenetriamine/dicyanamide; Mannich acrylamide polymers and polydimethyldiallylammonium halides. These additives, although tolerable, ofttimes fail to result in the isolation of the enzyme sufficiently e.g. the solids are not compacted; the supernatant has poor clarity, etc. Thus, the search for more effective flocculants is continuing and the discovery of useful materials which do not suffer from the deficiencies of the existing commercial flocculants would satisfy a long felt industrial need.