The fermented substrates are crumbled and extraction is done either in a batch or continuous process
The fermented substrates are crumbled and extraction is done either in a batch or continuous process. There are solutions used to leach the enzymes such as, water, aqueous buffer, diluted solutions of salts, 1% glycerol, or diluted solutions of non-ionic detergents namely Triton X-100, Tween 20, Tween 40, Tween 60, and Tween 80. These detergents are useful for the extraction of membrane-bound enzymes.
In general, 50-60 minute contact period is allowed with the solvent-to-solid ratio ranges from 1 to 8. The extraction temperature is about 30°C, yet a temperature between 4-10°C is preferable to avoid denaturation, proteolysis, and microbial growth. pH 7 allows the extraction process to be conducted, however pH close to pI is not preferable since it may produce precipitation. The optimum pH of enzymes may differ to the optimum pH for leaching, example is Rhizopus oligosporus acid protease is best extracted at pH 7 from fermented rice bran, yet it is most stable at pH 4.
There are two types of enzyme preparation, in liquid or solid form. In a case for the first one, enzyme is stabilized against chemical and microbial denaturation and degradation through the addition of high concentration of salt and preservatives. Some of specific antimicrobial preservatives are also added. Furthermore, in the solid form, enzymes are spray-dried in order to obtain the powdered form of the enzymes.