Physiological Changes and Growth Behavior of Cells in Biofilm

Biofilm cells are well-known for their increased survival and metabolic capabilities and have been increasingly implemented in industrial and biotechnological processes. is one of the most widely used microorganisms in the fermentation industry. However, biofilm has been rarely reported and little is known about its cellular basis. Here, the physiological changes and characteristics of biofilm cells during long-term fermentation were studied for the first time. Results showed that the biofilm cells maintained stable metabolic activity and cell size was enlarged after repeated-batch of fermentation. Cell division was slowed, and chromosome content and cell proliferation efficiency were reduced during long-term fermentation. Compared to free cells, more biofilm cells were stained by the apoptosis indicator dyes Annexin V-FITC and propidium iodide (PI). Overall, these results suggested slow-growing, long-lived cells of biofilm during fermentation, which could have important industrial implications. This study presents first insights into the physiological changes and growth behavior of biofilm cell population, which would be valuable for understanding and developing biofilm-based processes.