[Reduction of respiration and glucose uptake by bacteria after lyophilization]

The techniques of delayed fluorescence and potentiometry were used to study the restoration of respiration and the rate of glucose assimilation by E. coli M-17 rehydrated after lyophilization in various dehydrating media. The activity of respiration and the rate of glucose assimilation decreased after lyophilization, particularly if the cells were freeze-dried without protecting agents. The restoration of respiration and glucose assimilation to the stationary level took 20--60 min after rehydratation. The stationary level was lower than the level of respiration and glucose assimilation before lyophilization. The decrease in respiration and glucose assimilation after lyophilization correlated with the determination of the number of viable cells by the culturing technique only for effective protecting media, viz. sucrose-gelatin and milk. The absence of such a correlation for cells dehydrated in media with low-effective protecting properties is presumed to be due to their synthetic processes being disturbed and genetic damages.