Method of Increasing Enzyme Stability and Activity for Pulp and Paper Production

Abstract

Wood pulp is treated with an esterase formulation in combination with a metal ion or cationic polymer to increase the stability or activity or both of esterase enzymes at high temperature, or at extreme pH ranges of acidic and alkaline conditions. The treatment by esterase together with metals ion or cationic polymer can be used to treat pitch containing pulp at high temperatures prior to, during or after refining of wood chip/pulp, in order to enhance the reduction of pitch problems and facilitate in the manufacture of paper.

1 . A method of enhancing the reduction of pitch deposition or controlling pitch related problems during the pulp and paper making process, the method comprising:
 treating pitch-containing pulp stock at a temperature from 80° C. to 98° C. with a first enzyme formulation consisting essentially of one or more esterases (EC 3.1.1),   treating pitch-containing pulp, prior to or during the treatment with the first enzyme formulation, with one or more aluminum salts in an amount effective to stabilize the one or more esterases,   treating pitch-containing pulp, at a temperature below 80° C., with a second enzyme formulation comprising one or more enzymes.   
     
     
         2 . The method of  claim 1 , wherein the esterases are selected from the group consisting of lipase, phospholipases, carboxyl esterases, pectinesterases, and acetyl esterases. 
     
     
         3 . The method of  claim 1 , wherein the application dosage of the enzyme blend is from about 0.005% to 1.0% based on oven-dried fibers. 
     
     
         4 . (canceled) 
     
     
         5 . The method of  claim 1 , wherein the salt can be in the form of sulfate, sulfite, chloride, nitrate, perchlorate, phosphate, acetate, or an amino acid. 
     
     
         6 . The method of  claim 1 , wherein the cationic polymer is selected from the group consisting of epichlorohydrin/dimethylamine polymers (EPI-DMA) and cross-linked solutions thereof, polydiallyl dimethyl ammonium chloride (DADMAC), polyethylenimine (PEI), hydrophobically modified polyethylenimine, polyamines, resin amines, polyacrylamide, DADMAC/acrylamide copolymers, and ionene polymers. 
     
     
         7 . The method of  claim 1 , wherein the pitch containing pulp is treated with the first enzyme formulation for a time of from about 0.1 to 36 hours. 
     
     
         8 . The method of  claim 7  wherein the treatment with the first enzyme formulation is from about 0.5 to 15 hours. 
     
     
         9 . (canceled) 
     
     
         10 . The method of  claim 1  wherein the pitch containing pulp is treated in a location selected from the group consisting of latency chest, pulp storage chests, stock pumps, and white water streams. 
     
     
         11 . The method of  claim 1  wherein the pitch containing pulp is treated with the enzyme at a pH of between 3.0 and 11 or between 5 and 10. 
     
     
         12 . The method of  claim 1  wherein the application dosage of the metal ions is from about 0.1% to 10.0%, based on oven-dried fibers. 
     
     
         13 . The method of  claim 1  wherein the application dosage of the cationic polymer is from about 0.005% to 1.0% based on oven-dried fibers. 
     
     
         14 . A composition for enhancing the stability, or activity, or both stability and activity of esterases at elevated temperatures comprising one or more metal salt, a cationic polymer, or both metal salt and cationic polymer, in an amount effective to increase both the enzyme activity and stability. 
     
     
         15 . The composition of  claim 14 , wherein the esterase is selected from the group consisting of lipolytic enzyme, phospholipase, carboxyl esterase, pectinesterase, and acetyl esterase. 
     
     
         16 . The composition of  claim 13 , wherein the metal ion is selected from the group consisting of aluminum, calcium, magnesium, iron, copper, zinc, titanium and zirconium ions. 
     
     
         17 . The composition of  claim 14 , wherein the aluminum ion is in the form of a compound selected from the group consisting of aluminum sulfate, aluminum chloride, poly aluminum sulfate, and sodium aluminate. 
     
     
         18 . The composition of  claim 14 , wherein the cationic polymer is selected from the group consisting of epichlorohydrin/dimethylamine polymers and cross-linked solutions thereof, polydiallyl dimethyl ammonium chloride, polyethylenimine, hydrophobically modified polyethylenimine, polyamines, resin amines, polyacrylamide, DADMAC/acrylamide copolymers, and ionene polymers. 
     
     
         19 . The method of  claim 1 , wherein the second enzyme formulation comprises cellulase, hemicellulase, pectinase, amylase, laccase, or a combination thereof. 
     
     
         20 . The method of  claim 1 , wherein the esterase concentration is from about 0.005% to 1.0% based on oven-dried fibers. 
     
     
         21 . The method of  claim 20 , wherein the esterase concentration is from about 0.01% to 0.5% based on oven-dried fibers. 
     
     
         22 . The method of  claim 3 , wherein the application dosage of the enzyme blend is from 0.01 to 0.5% based on oven-dried fibers. 
     
     
         23 . The method of  claim 12 , wherein the application dosage of the metal ions is from 1% to 5% based on oven-dried fibers. 
     
     
         24 . The method of  claim 13 , wherein the application dosage of the cationic polymer is from 0.01 to 0.5% based on oven-dried fibers.