抄録
In the previous works1), 2) it has been reported that plenty of aerobic bacteria belonging to genus Bacillus are present in fish sausage and that fish sausage is in so anaerobic a condition as can hardly inhibit the growth of Bacillus. In tne present work the growth of those three kinds Bacillus, namely Bac.subtilis, Bac. coagulans and Bac. firmus, which have been isolated from fish sausage is studied under aerobic and anaerobic conditions, and at the same time are measured changes of the Eh of the media to be caused during their growth. Each of the Bacillus used for the purpose is cultured under three different conditions-aerated, aerobic stationary and anaerobic. The anaerobic culture is made by means of ROSENTHAL method. For the aerobic cultures, both methods aerated and stationry are used in order to vary the amount of oxygen to be put into the media, either method being usually taken for the purpose.
The results obtained are shown in Tables 1-3 and Figs. 1-3, which may be summarized as follows:
All the used bacteria can grow well in the aerobic conditions, though their growth is predominant in the aerated culture, but less so in the stationary one. The germination of spores takes place in Bac. subtilis and Bac. coagulans either in the aerobic or anaerobic condition, but Bac. firmus hardly germinates spores in the anaerobic condition. In the anaerobic condition Bac. subtilis seems to be able to grow vegetatively to some extent, though its sporulation seems difficult in it. As for Bac. coagulans, no such thing occurs.
As Bac. subtilis grows, the Eh value of the medium is lowered in the aerobic culture, but raised in the anaerobic one, consequently some definite range (-100 ?? -150m volt) is reached regardless of the cultural method to be used. As Bac. coagulans grows, the Eh value of the medium is lowered to be raised again. When Bac. firmus begins to grow, the Eh value is unchanged, but when it has reached the maximum of its growth, the Eh value is lowered to some definite degree. As to latter two kinds of bacteria, the Eh value in the aerated culture is always higher than that in the aerobic stationary culture, and these values are not lowered into minus range throughout their growing period.
