Flow microfluorometry studies of bacterial subpopulation dynamics and enzyme production in batch fermentation



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Production of enzymes in batch fermentation processes under different inoculum, operating and environmental conditions has been studied. A laser flow microfluorometer (FMF) has been used to monitor population dynamics of the bacterium Bacillus subtilis. Protein and nucleic acid contents of individual bacterial cells are measured at rates of the order of 5000 cells per second. Accumulation of such information over a few minutes yields the composition distribution of the microbial population. These distributions have been determined at different times during batch operation. Statistical analysis of these FMF experimental data has revealed that up to four subpopulations (endospores, vegetative cells, cell chains and coccobacilli) may be present in varying amounts at different times during the fermentation. Extracellular hydrolase enzyme production appears to be related to the interactions among these subpopulations. FMF analyses have shown that the physiological state of the inoculum has a significant effect on microbial subpopulation dynamics and thereby on secondary product synthesis. [...]