Hydrolase Enzymes are extracted from dead creatures using the Enzyme Extractor made by munitions traders.
The higher the CL of the creature, the better hydrolase can be extracted. Also, elite or boss creatures yield higher statistics than others of their same CL. The best hydrolase in the game are generally extracted from krayt dragons, with a unknown cap of purity(usually between 0-12) on an unrefined hydrolase.
Refined hydrolase can reach 20.0 purity, but can go above that in the mutagen rating.