This group of enzymes catalyze the hydrolysis of protein molecules. It is a mixture of pectin enzymes, proteinases, and peptidases. Most proteases are very specific in the peptide linkages they can break. Common sources are bacterial species like Pseudomonas, Clostridium, and Serratia as well as fungi such as Aspergillus Niger and Aspergillus Oryzae. High yielding strains are selected and grown in special culture media. These enzymes find use in detergents, beverage clarification, and cheese production.