Temperature-sensitive Bacillus subtilis natto and natto having low spore content
AssigneeMizkan Holdings Co., Ltd.
InventorAtsushi Ishikawa
Life of this patent
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Abstract
A method of producing natto includes inoculating a mutant strain of Bacillus subtilis var. natto onto steamed or boiled soybeans, and fermenting the soybeans inoculated with the mutant strain by maintaining a temperature of the soybeans at 40° C. to 53° C. The number of the mutant strain spores after fermenting the soybeans is 5×105 or less spores per gram of the fermented soybeans. A single colony of the mutant strain cultured in a selective solid medium supplemented with biotin at a gas phase temperature of 49° C. for 48 hours has a region having a hue of yellow (Y), a value of 9 or more, and a chroma of 2 or less, as defined by the Munsell Color System, and a surface area of the region is 20% or less of the total surface area of the single colony.
Claims13
A method of producing natto, comprising:
- inoculating a mutant strain of Bacillus subtilis var. natto onto steamed or boiled soybeans, wherein 1×103 to 1×106 spores of the mutant strain per gram of the soybeans are inoculated;
- and
- fermenting the soybeans inoculated with the mutant strain by maintaining a temperature of the soybeans at 40° C. to 53° C.,
- wherein the number of the mutant strain spores after fermenting the soybeans is 5×105 or less spores per gram of the fermented soybeans, and
- wherein the mutant strain has the following properties:
- a single colony of the mutant strain cultured in a selective solid medium supplemented with biotin at a gas phase temperature of 49° C. for 48 hours has a region having a hue of yellow (Y), a value of 9 or more, and a chroma of 2 or less, as defined by the Munsell Color System, wherein a surface area of the region is 20% or less of the total surface area of the single colony;
- and
- the number of the mutant strain spores is 1×107 spores/ml or more after culturing the mutant strain in a liquid medium for spore formation at a liquid temperature of 37° C.
A mutant strain of Bacillus subtilis var. natto having the following properties:
- a single colony of the mutant strain cultured in a selective solid medium supplemented with biotin at a gas phase temperature of 49° C. for 48 hours has a region having a hue of yellow (Y), a value of 9 or more, and a chroma of 2 or less, as defined by the Munsell Color System, wherein a surface area of the region is 20% or less of the total surface area of the single colony;
- and
- the number of the mutant strain spores is 1×107 spores/ml or more after culturing the mutant strain in a liquid medium for spore formation at a liquid temperature of 37° C.
A method of producing natto, comprising the following steps (i) to (iii):
- (i) a step of preparing a mutant strain of Bacillus subtilis var. natto strain having the following properties:
- a single colony of the mutant strain cultured in a selective solid medium supplemented with biotin at a gas phase temperature of 49° C. for 48 hours has a region having a hue of yellow (Y), a value of 9 or more, and a chroma of 2 or less, as defined by the Munsell Color System, wherein a surface area of the region is 20% or less of a total surface area of the single colony;
- (ii) a step of culturing the mutant strain obtained in (i) in a liquid medium for spore formation at a liquid temperature of 37° C. so that a number of mutant strain spores is 1×107 spores/ml or more;
- and
- (iii) a step of fermenting soybeans inoculated with the mutant strain by maintaining a temperature of the soybeans at 40° C. to 53° C., wherein the number of the mutant strain spores after fermenting the soybeans is 5×105 or less spores per gram of the fermented soybeans.
A method of producing natto, comprising the following steps (i) and (ii):
- (i) a step of preparing a mutant strain of Bacillus subtilis var. natto strain having the following properties:
- a single colony of the mutant strain cultured in a selective solid medium supplemented with biotin at a gas phase temperature of 49° C. for 48 hours has a region having a hue of yellow (Y), a value of 9 or more, and a chroma of 2 or less, as defined by the Munsell Color System, wherein a surface area of the region is 20% or less of a total surface area of the single colony;
- and
- (ii) a step of culturing the mutant strain obtained in (i) in a liquid medium for spore formation at a liquid temperature of 37° C. so that a number of the mutant strain spores.
Dependencies are inferred from the claim text.