Biological detergents contain protein-digesting enzymes produced by genetically engineered bacteria. Many of the stains on clothes, like blood and sweat, are proteins. Biological detergents have a number of advantages:
A mixture of enzymes called rennet is used during the production of cheese. Rennet is added to milk and helps to separate it into solid and liquid parts. Rennet can come from animal, fungal or plant sources, or can be produced by genetically modified bacteria.
In batch processing all the raw materials and the enzyme or cells are put into a vessel called a fermenter at the start. At the end the product and the enzyme must to be separated.
Immobilisation techniques restrict the movement of enzymes. This is usually done by attaching the enzymes to a solid substance such as a bead.
Immobilisation techniques allow continuous flow processing by holding the enzymes or cells in a column in a reactor vessel. The raw materials are fed into the top of the column continuously and the product is continuously removed from the bottom. This results in increased productivity and reduced costs compared to batch processing, as the process can be run non-stop for a long period of time.