抄録
As previously reported, the authors have confirmed that vitamin B12 is decomposed by several species of bacteria, such as Escherichia coli, Achromobactor, Pseudomonas and others. To ascertain the presence of the vitamin B12 de ?? troying eazymes, several experiments were carried out, using Escherichia coli. In these experiments vitamin B12 was determined by the Euglena method, after digesting bacterial cells with trypsin.
The extracellular enzyme was not detected, as the culture medium revealed no decomposing activity on the vitamin. The intact cell suspension, however, degraded the vitamin under the pre ?? ence of bacteriostatic agents such as toluene, chloroform and thymol as shown in Table 1. The cells killed and dried by Lyophil method were capable for the vitamin degradation, whereas the activity was lost entirely in the ace ?? onedried cells (Table 2).
