Enzymes and microorganisms having amidase activity for hydrolysing polyamides

An isolated enzyme with amidase activity towards substrates of the amide type having at least one of the following formulae:

• in which:
• A and B are monomer units,
• R1 and R3 are identical or different divalent radicals representing a substituted or unsubstituted, linear or branched alkylene, an arylene or an arylalkylene, and the number of carbons in the alkylene being greater than or equal to 4,
• R2 corresponds to identical or different radicals selected from hydrogen and alkyl radicals having from 1 to 6 carbons,
• X is:
• either X1=OH, OM or OR4, where M is selected from metals, and R4 is a linear or branched alkyl containing from 1 to 6 carbon atoms,
• or X2=
• where R2 and R3 are as defined above and R5 and R6, which are identical or different, have the same definition as that given above for R2,
• Y is:
• either Y1=hydrogen,
• or Y1=
• where R1 is as defined above and Z is hydrogen, a radical selected from metals or a radical which is a linear or branched alkyl containing from 1 to 6 carbon atoms,
• with the following conditions:
• if X=X1, then Y=Y1,
• if X=X2, then Y=Y2 or Y1,
• and p is between 1.5 and 10;
• or
• in which:
• R2 and R3 are as defined above,
• U and V respectively have the same definitions as those given above for X1 and Y1 in formula (I),
• and q=1 to 8,
• said enzyme being characterized by a ratio
• Ra=(enzymatic activity towards amide substrates of formula (I)(E.A.(I)))/(enzymatic activity towards amide substrates of formula (II)(E.A.(II))) which is greater than 2.