Treatment of Pulp Stocks Using Oxidative Enzymes to Reduce Pitch Deposition

Abstract

Methods of treating pulp stocks with an enzyme formulation containing one or more oxidative enzymes, to reduce pitch deposition, control pitch related problems, modify the physical and/or chemical properties of tri, di-, and mono-glycerides, fatty acids, resin acids, esters of fatty acids and resin acids, and metal soaps of fatty acids and resin acids, or change the concentration of triglycerides, fatty acids, resin acids, and esters of fatty acids and resin acids, have been developed. The pulp stock is treated with an enzyme formulation containing laccases, peroxidases, esterases, and/or combinations thereof. The enzyme formulations may also contain a laccase mediator and/or a dispersant. The enzyme formulation can be applied at any of several locations during the pulping and/or papermaking process. The enzyme formulation is typically applied as a solution to the pulp stock. The enzyme treatment is effective at a temperature of between about 30° C. to about 95° C., more preferably from about 50° C. to about 80° C. The pH of the pulp stock is from about 4.0 to about 7.0, more preferably from about 4.5 to 5.5. The stock can be treated for a period of time ranging from about 5 minutes to about 10 hours.

1 . A method of reducing pitch deposition or controlling pitch related problems during the pulp and paper making process, the method comprising 
 treating a semi-chemical, recycled, or mechanical pulp stock or Kraft pulp not having added transition metal compounds to facilitate enzymatic reactions,    with an effective amount of a formulation of one or more oxidative enzymes selected from the group consisting of a formulation reducing pitch deposition, a formulation controlling pitch related problems, a formulation modifying the physical and/or chemical properties of tri-, di-, and mono-glycerides, fatty acids, resin acids, esters of fatty acids and resin acids, and metal soaps of fatty acids and resin acids, and a formulation changing the concentration of triglycerides, fatty acids, resin acids, and esters of fatty acids and resin acids.    
   
   
       2 . The method of  claim 1 , wherein the one or more oxidative enzymes is selected from the group consisting of oxidases, peroxidases, and combinations thereof.  
   
   
       3 . The method of  claim 1  wherein the formulation further comprises one or more compounds selected from the group consisting of redox mediators, dispersants, surfactants and combinations thereof.  
   
   
       4 . The method of  claim 3  wherein the redox mediator is selected from the group consisting of 2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate (ABTS); 6-hydroxy-2-naphtoic acid; 7-methoxy-2-naphtol; 7-amino-2-napththalene sulfonic acid; 5-amino-2-naphthalene sulfonic acid; 1,5-diaminonaphthalene; 7-hydroxy-1,2-naph-thimidazole; 10-methylphenothiazine; 10-phenothiazine-propionic acid (PPT); N-hydroxysuccinimide-10-phenothiazine-propionate; benzidine; 3,3′-dimethylbenzidine; 3,3′-dimethoxybenzidine; 3,3′,5,5′-tetramethylbenzidine; 4′-hydroxy-4-biphenylcarboxylic acid; 4-amino-4′-methoxystilbene; 4,4′-diaminostilbene-2,2′-disulfonic acid; 4,4′-diaminodiphenylamine; 2,7-diaminofluorene; 4,4′-dihydroxy-biphenylene; triphenylamine; 10-ethyl-4-phenothiazinecarboxylic acid; 10-ethylphenothiazine; 10-propyl-phenothiazine; 10-isopropyl phenothiazine; methyl-10-phenothiazinepropionate; 10-phenylphenothiazine; 10 allyl-phenothiazine; 10-phenoxazinepropionic acid (POP); 10-(3-(4-methyl-i-piperazinyl)propyl)phenothiazine; 10-(2-pyrrolidinoethyl)phenothiazine; 10-methylphenoxazine; iminostilbene; 2-p-aminophenyl)-6-methylbenzothiazole-7-sulfonic acid; N-benzylidene-4-biphenylamine; 5-amino-2-naphthalenesulfonic acid; 7-methoxy-2-naphtol; 4,4′-dihydroxybenzophenone; N-(4-(dimethylamino)benzylidene)-p-anisidine; 3-methyl-2-benzo-thiazolinone(4-(dimethylamino)benzylidene)hydrazone; 2-acetyl-10-methylphenothiazine; 10-(2-hydroxyethyl)phenothiazine; 10-hydroxyethyl)phenoxazine; 10-(3-hydroxypropyl)phenothiazine; 4,4′-dimethoxy-N-methyl-diphenylamine, and vanillin azine.  
   
   
       5 . The method of  claim 3  wherein the dispersant is selected from the group consisting of primary and branched alkoxylates, fatty acid alkoxylates, phosphate esters and their alkoxylates, alkylphenol alkoxylates, block copolymers of ethylene and propylene oxide, alkanesulfonates, olefinsulfonates, fatty amine alkoxylates, glyceride alkoxylates, glycerol ester alkoxylates, sorbitan ester alkoxylates, polyethylene glycol esters, polyalkylene glycols, polyacrylic acids, sodium polyacrylate, acrylic acid copolymer, acrylate copolymer, acrylic crosslinked copolymer, and their derivatives; maleic acid and acrylic acid or acrylate copolymer, maleic acid/olefin copolymer, and their derivatives, polyvinyl alcohol/polyvinyl acetate copolymers, polyvinyl pyrrolidone, and their derivatives, and combinations thereof.  
   
   
       6 . The method of  claim 2  wherein the oxidase enzymes are selected from the group consisting of laccases, glucose oxidases, alcohol oxidases, cholesterol oxidases, fatty acid oxidases, polyvinyl alcohol oxidases, and polyphenyl oxidases.  
   
   
       7 . The method of  claim 2  where the peroxidase enzymes are selected from the group consisting of fatty acid peroxidases, catalases and manganese peroxidases.  
   
   
       8 . The method of  claim 6  wherein the concentration of laccase is from about 1 to about 50,000 laccase units (LAMU or LCU) per kilogram of oven-dried fibers.  
   
   
       9 . The method of  claim 8 , wherein the concentration of laccase is from about 10 to about 10,000 laccase units (LAMA or LCU) per kilogram of over-dried fibers.  
   
   
       10 . The method of  claim 8  wherein the concentration of laccase is from about 50 to about 1,000 laccase units (LAMU or LCU) per kilogram of oven-dried fibers.  
   
   
       11 . The method of  claim 7  wherein the concentration of peroxidase is from about 2 to about 20,000 peroxidase units (PU) per kilogram of oven dried fibers.  
   
   
       12 . The method of  claim 11  wherein the concentration of peroxidase is preferably from about 20 to about 10,000 peroxidase units (PU) per kilogram of oven-dried fibers.  
   
   
       13 . The method of  claim 11  wherein the concentration of peroxidase is from about 50 to about 5,000 peroxidase units (PU) per kilogram of OD oven dried fibers.  
   
   
       14 . The method of  claim 6  wherein the concentration of glucose oxidase is from about 1 to about 10,000 glucose oxidase units (GOU) per kilogram of oven dried fibers.  
   
   
       15 . The method of  claim 14  wherein the concentration of glucose oxidase is from about 10 to about 2,000 glucose oxidase unit (GOU) per kilogram of oven-dried fibers.  
   
   
       16 . The method of  claim 14  wherein the concentration of glucose oxidase is from about 50 to about 500 glucose oxidase units (GOU) per kilogram of OD oven dried fibers.  
   
   
       17 . The method of  claim 4  wherein the concentration of the redox mediator is from about 0.005 to about 3 kilograms/ton of oven dried fibers.  
   
   
       18 . The method of  claim 17  wherein the concentration of the redox mediator is from about 0.0002 to about 3 kilograms/ton of oven dried fibers.  
   
   
       19 . The method of  claim 5  wherein the concentration of the dispersant is from about 0.002 to about 10 kilograms/ton oven dried fibers.  
   
   
       20 . The method of  claim 19  wherein the concentration of the dispersant is from about 0.004 to about 3 kilograms/ton of oven dried fibers.  
   
   
       21 . The method of  claim 5  where the polyvinyl pyrrolidone and their derivatives is selected from the group consisting of a molecular weight between 7,000 to 2,500,000 daltons, more preferably between 400,000 and 2,000,000.  
   
   
       22 . The method of  claim 5  wherein the polyvinyl alcohol/polyvinyl acetate copolymers is selected from the group consisting of a molecular weight between 5,000 and 500,000 daltons, more preferably between 50,000 and 150,000, and a hydrolysis decree between 50% and 100%, more preferably between 70% and 95%.  
   
   
       23 . The method of  claim 1  wherein the pulp stock is produced by a process selected from the group consisting of mechanical pulping, semichemical pulping, chemi-theromomechanical pulping, bleached Kraft pulping and recovered fiber pulping.  
   
   
       24 . The method of  claim 1  wherein the pulp is a mechanical pulp selected from the group consisting of groundwood pulp, pressurized groundwood pulp and thermomechanical pulp.  
   
   
       25 . The method of  claim 1  wherein the pulp stock has been previously treated with a lipolytic enzyme.  
   
   
       26 . The method of  claim 1  further comprising treating the pulp stock with the oxidative enzyme in combination with a lipolytic enzyme.  
   
   
       27 . The method of  claim 1  wherein the pulp stock is subsequently treated with a lipolytic enzyme.  
   
   
       28 . The method of  claim 1  wherein the pulp stock is treated in a location selected from the group consisting, of the latency chest, the reject refiner chest, the disk filter and decker, TMP whitewater, the low density (“LD”) chest, the medium density (“MD”) chest, the high density (“HD”) chest, the decker, the blend chest, the machine chest, the headbox, the white water system, and the paper machine (“PM”).  
   
   
       29 . The method of  claim 1  wherein the formulation is maintained in the pulp stock at a temperature of about 30° C. to about 95° C.  
   
   
       30 . The method of  claim 29  wherein the formulation is maintained in the pulp stock at a temperature of about 50° C. to about 80° C.  
   
   
       31 . The method of  claim 1  wherein the formulation is maintained in the pulp stock at a pH of about 4.0 to about 7.0.  
   
   
       32 . The method of  claim 31  wherein the formulation is maintained in the pulp stock at a pH of about 4.5 to about 5.5.  
   
   
       33 . The method of  claim 1  wherein the pulp stock is treated with alum and an effective amount of one or more oxidative enzymes.  
   
   
       34 . The method of  claim 1  wherein the pulp stock is treated with laccase and an effective amount of one or more other oxidative enzymes.