Novel urethanases for the enzymatic degradation of polyurethanes

Abstract

The present invention relates to new urethanases for the enzymatic breakdown of polyurethanes and to an enzymatic process for the complete breakdown of polyurethanes into defined monomers.

1 .- 11 . (canceled) 
     
     
         12 . A process for breaking down polyester polyurethanes into low-molecular-weight breakdown products, comprising the steps of
 a) cleaving the ester groups present in the polyester polyurethane; and   b) cleaving the urethane groups present in the polyester polyurethane with a polypeptide that has urethanase activity;   with the proviso that process steps a) and b) may be carried out in either order or else in parallel.   
     
     
         13 . The process as claimed in  claim 12 , wherein the polypeptide that has urethanase activity has an amino acid sequence selected from the group consisting of SEQ ID No. 1 to SEQ ID No. 10, and amino acid sequences having at least 90% sequence identity with the sequences SEQ ID No. 1 to SEQ ID No. 10. 
     
     
         14 . The process as claimed in  claim 12 , wherein process step a) is carried out before process step b). 
     
     
         15 . The process as claimed in  claim 12 , wherein polyols, polycarboxylic acids, and polyamines are formed as process products. 
     
     
         16 . The process as claimed in  claim 15 , wherein at least one polyamine selected from the group consisting of methylene-4,4′-diamine, methylene-2,4′-diamine, methylene-2,2′-diamine, naphthylene-1,4-diamine, naphthylene-1,5-diamine, naphthylene-1,6-diamine, tolylene-2,4-diamine, and tolylene-2,6-diamine is formed. 
     
     
         17 . The process as claimed in  claim 15 , wherein at least one polyol selected from the group consisting of ethylene glycol, diethylene glycol, 1,4-butanediol, triethylene glycol, propylene glycol, 1,2-dipropylene glycol, neopentyl glycol, glycerol, 1,1,1-trimethylolpropane, sucrose, sorbitol, and pentaerythritol is formed. 
     
     
         18 . The process as claimed in  claim 15 , wherein at least one polycarboxylic acid selected from the group consisting of succinic acid, glutaric acid, adipic acid, phthalic acid, terephthalic acid, benzenetricarboxylic acid, oleic acid, and ricinoleic acid is formed. 
     
     
         19 . The process as claimed in  claim 12 , wherein process step a) is carried out with a lipase. 
     
     
         20 . The process as claimed in  claim 19 , wherein the lipase has an amino acid sequence as in SEQ ID No. 11 or SEQ ID No. 12 or a variant of the abovementioned sequences having at least 90% sequence identity with SEQ ID No. 11 or SEQ ID No. 12. 
     
     
         21 . A method comprising utilizing a polypeptide having an amino acid sequence selected from the group consisting of SEQ ID No. 3, SEQ ID No. 2, SEQ ID No. 4, SEQ ID No. 5, SEQ ID No. 6, SEQ ID No. 8, SEQ ID No. 10 and variants of said polypeptides or of a GatA-similar polypeptide having an amino acid sequence in accordance with SEQ ID No. 7 or a variant thereof, wherein the polypeptide has urethanase activity in the enzymatic cleavage of urethane linkages. 
     
     
         22 . The method according to  claim 21 , wherein the urethane group is aromatically attached.