Nuclease Reduction

Abstract

A method for reducing nuclease activity in a subtilisin solution obtained from a fermentation broth comprising a) adjusting the pH of the subtilisin solution to a pH in the range of from pH 8.5 to pH 10.5; b) adding a polyol; c) adjusting the temperature of the subtilisin solution to a temperature in the range of from 50° C. to 80° C.; whereby the nuclease activity is reduced to less than 5% of the initial value and the subtilisin activity is maintained at more than 80% of the initial value.

1 . A method for reducing nuclease activity in a subtilisin solution obtained from a fermentation broth comprising
 a) adjusting the pH of the subtilisin solution to a pH in the range of from pH 8.5 to pH 10.5;   b) adding a polyol;   c) adjusting the temperature of the subtilisin solution to a temperature in the range of from 50° C. to 80° C.;   whereby the nuclease activity is reduced to less than 5% of the initial value and the subtilisin activity is maintained at more than 80% of the initial value.   
     
     
         2 . The method according to  claim 1 , wherein the nuclease is a ribonuclease (RNase) or a deoxyribonuclease (DNase). 
     
     
         3 . The method according to  claim 1 , wherein the subtilisin is selected from the group consisting of subtilisin Carlsberg, subtilisin BPN′, subtilisin 147, subtilisin 309 and subtilisin 1168. 
     
     
         4 . The method according to  claim 1 , wherein the subtilisin is produced by  Bacillus.    
     
     
         5 . The method according to  claim 1 , wherein the subtilisin solution is an ultrafiltrated fermentation broth. 
     
     
         6 . The method according to  claim 1 , wherein the pH of the subtilisin solution is adjusted to a pH in the range of from pH 9.0 to pH 10.0. 
     
     
         7 . The method according to  claim 1 , wherein the temperature of the subtilisin solution is adjusted to a temperature in the range of from 60° C. to 70° C. 
     
     
         8 . The method according to  claim 1 , wherein the nuclease activity is reduced to less than 1% of the initial value. 
     
     
         9 . The method according to  claim 1 , wherein the subtilisin activity is maintained at more than 90% of the initial value. 
     
     
         10 . The method according to  claim 1 , wherein the polyol is selected from the group consisting of 1,2-propandiol (monopropylene glycol or MPG), 1,3-propandiol, glycerol, ethylene glycol, xylitol, arabitol, dulcitol, mannitol, erythritol, cellobiose and sorbitol. 
     
     
         11 . The method according to  claim 1 , wherein the subtilisin solution is incubated at the high pH and at the high temperature for a period of up to 10 minutes. 
     
     
         12 . The method according to  claim 1 , wherein step b) is performed before step a).