Method for killing microorganism

Abstract

Provided is a technique for enabling a liquid of microbial cells having an enzymatic activity to be easily stored and used. The technique is a method for killing a microorganism while maintaining the enzyme titer of a microbial cell liquid, characterized by including adjusting the pH of a liquid of microbial cells having an enzymatic activity, and then performing a heating treatment of the liquid, and also the technique is a method for killing a microorganism while maintaining the enzyme titer of a microbial cell liquid, characterized by including adding a carbohydrate to a liquid of microbial cells having an enzymatic activity, and then performing a heating treatment of the liquid.

1 . A method for killing a microorganism while maintaining an enzyme titer of a microbial cell liquid, the method comprising adjusting the pH of a liquid of microbial cells having an enzymatic activity, and then performing a heating treatment of the liquid, wherein an enzyme titer of the liquid of microbial cells is maintained. 
     
     
         2 . The method of  claim 1 , wherein the pH of the liquid of microbial cells is adjusted to 3.5 to 6.5. 
     
     
         3 . The method of  claim 1 , wherein the heating treatment is performed at 40 to 50° C. for at least 1 hour. 
     
     
         4 . The method of  claim 1 , wherein the enzymatic activity is β-galactosidase activity. 
     
     
         5 . The method of  claim 1 , wherein the microbial cells are yeast cells. 
     
     
         6 . The method of  claim 5 , wherein the yeast is  Sporobolomyces singularis.    
     
     
         7 . The method of  claim 1 , wherein the enzyme titer after performing the heating treatment is 80% or more of the enzyme titer before performing the heating treatment. 
     
     
         8 . The method of  claim 1 , further comprising adding a carbohydrate to the liquid of microbial cells (i) before adjusting the pH, (ii) after adjusting the pH but before performing the heating treatment, or both (i) and (ii). 
     
     
         9 . The method of  claim 8 , wherein the carbohydrate is added in an amount of 0.2 to 30 mass/vol %. 
     
     
         10 . The method of  claim 1 , wherein the pH is adjusted using a carbonate. 
     
     
         11 . A killed microbial cell liquid, wherein an enzyme titer of a microbial cell liquid before killing microbial cells is maintained. 
     
     
         12 . The killed microbial cell liquid of  claim 11 , wherein the microbial cells have β-galactosidase activity. 
     
     
         13 . The killed microbial cell liquid of  claim 11 , wherein the microbial cells are yeast cells. 
     
     
         14 . The killed microbial cell liquid of  claim 13 , wherein the yeast is  Sporobolomyces singularis.    
     
     
         15 . The killed microbial cell liquid of  claim 11 , wherein the enzyme titer after killing the microbial cells is 80% or more of the enzyme titer before killing the microbial cells. 
     
     
         16 . The killed microbial cell liquid of  claim 11 , obtained by adjusting the pH of a liquid of microbial cells having an enzymatic activity, and then performing a heating treatment of the liquid, wherein an enzyme titer of the liquid of microbial cells is maintained. 
     
     
         17 . The killed microbial cell liquid of  claim 16 , wherein the pH of the microbial cell liquid is adjusted to 3.5 to 6.5. 
     
     
         18 . The killed microbial cell liquid of  claim 16 , wherein the microbial cell liquid is heated at 40 to 50° C. for at least 1 hour. 
     
     
         19 . The killed microbial cell liquid of  claim 16 , wherein a carbohydrate is added to the liquid of microbial cells (i) before adjusting the pH, (ii) after adjusting the pH but before performing the heating treatment, or both (i) and (ii). 
     
     
         20 . The killed microbial cell liquid of  claim 19 , wherein the carbohydrate is added in an amount of 0.2 to 30 mass/vol %. 
     
     
         21 . The killed microbial cell liquid of  claim 16 , wherein the pH is adjusted using a carbonate. 
     
     
         22 . A dry killed microbial cell powder obtained by drying the killed microbial cell liquid of  claim 11 . 
     
     
         23 . An enzyme composition comprising the killed microbial cell liquid of  claim 11 . 
     
     
         24 . A method for killing a microorganism while maintaining an enzyme titer of a microbial cell liquid, the method comprising adding a carbohydrate to a liquid of microbial cells having an enzymatic activity, and then performing a heating treatment of the liquid, wherein an enzyme titer of the liquid of microbial cells is maintained. 
     
     
         25 . The method of  claim 24 , wherein the heating treatment is performed at 40 to 55° C. for at least 1 hour. 
     
     
         26 . The method of  claim 24 , wherein the enzymatic activity is β-galactosidase activity. 
     
     
         27 . The method of  claim 24 , wherein the microbial cells are yeast cells. 
     
     
         28 . The method of  claim 27 , wherein the yeast is  Sporobolomyces singularis.    
     
     
         29 . The method of  claim 24 , wherein the carbohydrate is added to the liquid of microbial cells in an amount of 0.2 to 30 mass/vol %. 
     
     
         30 . The method of  claim 24 , wherein the carbohydrate is at least one carbohydrate selected from the group consisting of lactose, glucose, maltose, a galactooligosaccharide, and a dextrin. 
     
     
         31 . The method of  claim 24 , wherein the enzyme titer after performing the heating treatment is 80% or more of the enzyme titer before performing the heating treatment. 
     
     
         32 . A killed microbial cell liquid, comprising a carbohydrate, wherein an enzyme titer of a microbial cell liquid before killing microbial cells is maintained. 
     
     
         33 . The killed microbial cell liquid of  claim 32 , wherein the microbial cells have β-galactosidase activity. 
     
     
         34 . The killed microbial cell liquid of  claim 32 , wherein the microbial cells are yeast. 
     
     
         35 . The killed microbial cell liquid of  claim 34 , wherein the yeast is  Sporobolomyces singularis.    
     
     
         36 . The killed microbial cell liquid of  claim 32 , comprising the carbohydrate in an amount of 0.2 to 30 mass/vol %. 
     
     
         37 . The killed microbial cell liquid of  claim 32 , wherein the carbohydrate is at least one carbohydrate selected from the group consisting of lactose, glucose, galactose, a lactose isomer, a galactooligosaccharide, maltose, a maltooligosaccharide, and a dextrin. 
     
     
         38 . The killed microbial cell liquid of  claim 32 , wherein the enzyme titer after killing the microbial cells is 80% or more of the enzyme titer before killing the microbial cells. 
     
     
         39 . The killed microbial cell liquid of  claim 32 , obtained by adding the carbohydrate to the liquid of microbial cells having an enzymatic activity, and then performing a heating treatment of the liquid, wherein an enzyme titer of the liquid of microbial cells is maintained. 
     
     
         40 . The killed microbial cell liquid of  claim 39 , wherein the heating treatment is performed at 40 to 55° C. for at least 1 hour. 
     
     
         41 . A dry killed microbial cell powder obtained by drying the killed microbial cell liquid of  claim 32 . 
     
     
         42 . An enzyme composition comprising the killed microbial cell liquid of  claim 41 .