PROBLEM TO BE SOLVED: To provide a Natto bacillus strain producible of natto finished soft without remaining filmy skin in mouth, having the feeling of a sufficient umami, and not soybean smell but a good fermenting smell, in the natto obtained by using a colored soybean which is difficult to be fermented by a conventional Natto bacillus strain.SOLUTION: By using the Natto bacillus strain, Bacillus subtilis IBARAKI C-1 strain (FERM P-22078) which is a new microorganism variant strain belonging to the Bacillus subtilis, or the Natto bacillus strain obtained by mixing the above Natto bacillus strain with Bacillus subtilis IBARAKI P-1 strain (FERM P-22079) at a ratio of (8:2) in mass ratio, the soft natto having the feeling of the sufficient umami and good fermenting smell can be produced.COPYRIGHT: (C)2013,JPO&INPIT【課題】既存納豆菌株で十分な発酵が困難な有色素大豆を用いた納豆において、表皮が口に残らず柔らかく仕上がり、十分な旨みを感じ、大豆臭ではなく、良い発酵臭を感じる納豆を作ることの出来る納豆菌株、納豆及びその製造方法を提供する。【解決手段】バチルス・サブチリス(Bacillus subtilis)に属する新規な微生物変異株であるバチルス・サブチリスIBARAKI C-1(FERM P-22078)である納豆菌株、あるいは、当該納豆菌株とバチルス・サブチリス(Bacillus subtilis)IBARAKI P-1株(FERM P-22079)の混合割合が質量比で8:2である納豆菌株を用いることにより、柔らかく、十分な旨みと良い発酵臭を感じる納豆を製造することができる方法。【選択図】なし
