There are three types of different media for bacterial growth :They are turbid growth, precipitation growth and bacterial film growth (surface growth)
1.Turbid growth: most bacteria grow and propagate in liquid media and become turbid evenly. Such as Escherichia coli, Shigella, etc.
2. Precipitation growth: a small number of chain bacteria, such as Streptococcus, Bacillus anthracis and so on, are precipitation growth.
3. Membrane growth (surface growth): specialized aerobic bacteria such as Bacillus subtilis, Mycobacterium tuberculosis and Pseudomonas aeruginosa generally grow on the surface and often form a membrane.
When the bacteria are inoculated in the liquid culture media, the liquid culture media will become turbid after the bacteria grow. Turbidity varies according to the different oxygen demand of bacteria: aerobic bacteria only make the upper culture liquid turbid, anaerobic bacteria make the bottom culture liquid turbid, facultative anaerobic bacteria make the culture liquid uniformly turbid; some bacteria can form a bacterial ring or membrane on the surface of the culture liquid, or produce sedimentation at the bottom.
Growth of bacteria in liquid culture media is mainly used for bacteria enrichment. Bacteria grow and propagate in the liquid culture media, which shows that the liquid becomes turbid, the surface forms bacterial membrane, and the bottom of the culture tube forms sediment.