The invention concerns a method for the enzymatic treatment of raw polymeric feedstock comprising the following steps: (a) preferably separation of soluble components from the raw polymeric feedstock, (b) treating the raw polymeric feedstock with an enzyme system in order to liberate defined soluble monomeric or oligomeric building blocks from the insoluble raw polymeric feedstock; and (c) separating the defined monomeric or oligomeric building blocks produced in step b) from the remainder of the raw polymeric feedstock. Preferably, the enzyme system used in step b) contains not more than 50%, preferably not more than 20%, more preferably not more than 10%, more preferably not more than 5%, more preferably not more than 2%, more preferably not more than 1% of other enzyme activities apart from the enzyme activity resulting in liberation of said defined monomeric or oligomeric building blocks from the raw polymeric feedstock according to step b). Further aspects of the invention concern the use of “less pure” and thus less costly enzyme systems in subsequent enzymatic treatment steps and methods for determining the optimum sequence of enzymatic treatment steps by analysis of the raw polymeric feedstock used.