Bacteria are unicellular organisms that reproduce asexually via binary fission. Rather than an increase in their cell size, bacterial growth is the increase in the number of bacterial cells. The growth of these bacterial cells is exponential, meaning that one cell splits into two, then four, then eight, sixteen, thirty-two, and so on.
The time required for a bacterial cell to divide is referred to as its generation time. The generation time of different bacterial species depends on the environmental conditions in which they thrive. The fastest growing bacteria is Clostridium perfringens, with a generation time of 10 minutes compared to Escherichia coli's doubling time of 20 minutes. Mycobacterium tuberculosis is one of the microorganisms with the slowest growth rate, doubling every 12 to 16 hours.
Upon introduced into the nutritional medium, the bacteria require time to adapt to their new surroundings. During this phase, bacteria do not reproduce but instead prepare for reproduction. The cells are metabolically active and continue to expand. RNA, growth factors, and other chemicals essential for cell division are synthesised by the cells.
Bacteria enter the log phase after the preparation phase, or lag phase. Log phase is exponential phase. Bacteria double in this period. Logarithmic cell growth maintains cell component. Nutrient depletion ends the log phase. Toxic compounds inhibit growth and halt the stage. Researchers favour bacteria from this stage for their experiments because the cells are the healthiest. This phase's bacterial growth curve is straight. This line's slope gives the organism's growth rate. It measures cell divisions per time.
In the stationary phase, the rate of cell growth equals the rate of cell death. Accumulation of hazardous chemicals and depletion of nutrients in the medium limit the rate of growth of bacterial cells. At this stage, the cell population remains steady. The result of plotting this phase on a graph is a straight horizontal line.
This is the final stage of bacterial development. At this stage, the rate of cell death exceeds the rate of cell production. Lack of nutrition, physical circumstances, or other cell damage result in cell death.