納豆生成に関与するバクテリアを分離して、一種は新種であるとして Bacillus nattoと名付け、馬鈴薯菌（Bacillus mesetericus vulgatus）との混用により、納豆を製造できると報告した。
著者：澤村真
農科大学学術報告 第七巻第一号
On the Micro-organisms of Natto
Bacillus No. 1.
Bacillus No. 2.
著者：澤村真
農科大学学術報告 第七巻第一号 
BULLETIN OF THE COLLEGE OF AGRICULTURE, TOKYO IMPERIAL UNIVERSITY, JAPAN
vol.7, no.1, 1906, p107-110.
vol.7, no.1, 1906, p107-110.
On the Micro-organisms of Natto
Natto is a kind of vegetable cheese prepared in Japan by fermentation of boiled soy-beans wrapped in rice straw and left for one or two days in a warm place.
This product contains much mucilage filled with innumerable bacteria and it is the great viscosity that is especially esteemed with this cheese.
Yabe isolated from natto three species of micrococci which formed yellow, orange and white colonies respectively, and formed white colonies on soy-bean.
According to Yabe the micrococci of the yellow colonies produced the peculiar aroma of natto when cultured on soy-bean, but thus far it was not decided which microbe gives rise to the viscous substance or mucilage.
Yabe has found that a large part of the albuminoids of soy-bean is decomposed to pepton and amido-compounds by the fermentation.
The micro-organisms of natto consist in the beginning chiefly of bacilli, but on being kept for some time micrococci gain predominance.
The Writer isolated various kinds of bacilli and micrococci from natto and observed their behavior in cultures on sterilised soy-bean.
Two kinds of bacilli grew well on soy-bean and formed a product similar to natto in regard to taste, aroma and viscosity.
Other bacilli, however, and micrococci in developing on soy-bean did not produce a palatable product, nor did mixed cultures of them with the former two species.
Also the behavior of Bacillus mesentericus vulgatus, Bac. mes. fuscus, Bac. subtilis, Bacterium filiform and B. tyrothrix filiformis was observed by the writer, but the products formed were of disagreeable taste and odor.
The writer infered that although many bacteria can grow on soy-bean, the genuine natto can only be produced by certain bacilli thus for isolated form the natto-cheese.
These bacilli show the following characteristics:
This product contains much mucilage filled with innumerable bacteria and it is the great viscosity that is especially esteemed with this cheese.
Yabe isolated from natto three species of micrococci which formed yellow, orange and white colonies respectively, and formed white colonies on soy-bean.
According to Yabe the micrococci of the yellow colonies produced the peculiar aroma of natto when cultured on soy-bean, but thus far it was not decided which microbe gives rise to the viscous substance or mucilage.
Yabe has found that a large part of the albuminoids of soy-bean is decomposed to pepton and amido-compounds by the fermentation.
The micro-organisms of natto consist in the beginning chiefly of bacilli, but on being kept for some time micrococci gain predominance.
The Writer isolated various kinds of bacilli and micrococci from natto and observed their behavior in cultures on sterilised soy-bean.
Two kinds of bacilli grew well on soy-bean and formed a product similar to natto in regard to taste, aroma and viscosity.
Other bacilli, however, and micrococci in developing on soy-bean did not produce a palatable product, nor did mixed cultures of them with the former two species.
Also the behavior of Bacillus mesentericus vulgatus, Bac. mes. fuscus, Bac. subtilis, Bacterium filiform and B. tyrothrix filiformis was observed by the writer, but the products formed were of disagreeable taste and odor.
The writer infered that although many bacteria can grow on soy-bean, the genuine natto can only be produced by certain bacilli thus for isolated form the natto-cheese.
These bacilli show the following characteristics:
Bacillus No. 1.
Form: Cells cultured on bouillon at 30ºC for 24 hours are 1µ wide and 3-4µ long. The ends of the rod are rounded. The baciili unite sometime to a long thread.
Motility: The Bacillus of young cultures is motile.
...(Omitted)
Natto produced by this bacillus has a good taste and aroma, but is not of so strong viscosity as that produced by Bcillus No.2.
The colonies of Bacillus No. 1 appear always in large number when plate cultures from natto are made.
Hence it become probable that this microbe exerts the chief action in the fermentation of natto.
It resembles somewhat Bacillus mesentericus, still it differs again considerably.
The writer considers it a new species which received the name of Bacillus natto.
Motility: The Bacillus of young cultures is motile.
...(Omitted)
Natto produced by this bacillus has a good taste and aroma, but is not of so strong viscosity as that produced by Bcillus No.2.
The colonies of Bacillus No. 1 appear always in large number when plate cultures from natto are made.
Hence it become probable that this microbe exerts the chief action in the fermentation of natto.
It resembles somewhat Bacillus mesentericus, still it differs again considerably.
The writer considers it a new species which received the name of Bacillus natto.
Bacillus No. 2.
Form: Cells cultured on bouillon at 30ºC for 24 hours are 1µ wide and 3µ long. The ends of the rod are rounded and two or more areoften united.
Motility: It already moves.
...(Omitted)
Soy-beans changed by this bacillus show a stronger viscosity but a less agreeable taste and aroma than those produced by Bac. No. 1.
It resembles Bac. mes. vulgatus, of which iti is probably a variety.
It is probable that for formentation of s good natto-cheese both the bacilli just described must be present.
In order to test for enzyms produced on soy-beans by Bac. No. 1 and No. 2, the precipitates obtained by alcohol with the extracts were redisolved in water and once more precipitated.
The aqueous solution in presence of some thymol quickly dissolved the proteins of soy-bean at 36ºC.
This proteolytic action was accelerated by 0.3% Na2CO2 but retarded by 0.2% HCl, acetic or lactic acid; hence the enzym was of tryptic mature.
Bac. No. 2 produced also a diastatic enzym which was comfirmed by formation of reducing sugar in bouillon containing starch.
From these facts we can infer that natto may exert some beneficial action on digestion.
The writer expresses his thanks to Mr. T. Yamasaki, assistant of the College who assisted him in these investigations.
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Motility: It already moves.
...(Omitted)
Soy-beans changed by this bacillus show a stronger viscosity but a less agreeable taste and aroma than those produced by Bac. No. 1.
It resembles Bac. mes. vulgatus, of which iti is probably a variety.
It is probable that for formentation of s good natto-cheese both the bacilli just described must be present.
In order to test for enzyms produced on soy-beans by Bac. No. 1 and No. 2, the precipitates obtained by alcohol with the extracts were redisolved in water and once more precipitated.
The aqueous solution in presence of some thymol quickly dissolved the proteins of soy-bean at 36ºC.
This proteolytic action was accelerated by 0.3% Na2CO2 but retarded by 0.2% HCl, acetic or lactic acid; hence the enzym was of tryptic mature.
Bac. No. 2 produced also a diastatic enzym which was comfirmed by formation of reducing sugar in bouillon containing starch.
From these facts we can infer that natto may exert some beneficial action on digestion.
The writer expresses his thanks to Mr. T. Yamasaki, assistant of the College who assisted him in these investigations.
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