The strains in fermentation are generally fermented in solid or liquid form.Solid strains have to go through test tube seed, primary seed and secondary seed in the fermentation process, while liquid strains are usually inoculated into fermenters after shake flask fermentation.Besides the different fermentation processes, why do more fermentation production choose liquid bacteria?
 
The difference between liquid and solid strains
1. Growth of strains: liquid strains grow fast, short cycle, strong reproduction ability and high production efficiency under the optimum temperature, pH, oxygen and other conditions in the tank. The solid strain grows slowly, with long cycle, and the yield is far inferior to the liquid strain.
2. Cost of strains: liquid strains are less expensive than solid strains.
3. Transportation of strains: liquid strains are highly mobile and active, with high transportation requirements, otherwise it is easy to cause pollution. Solid strains are not easy to break and easy to transport.
4. Preservation of strains: liquid strains with the increase of microorganisms, strong oxygen consumption, can not be stored for a long time. While solid strains are relatively stable, normal storage can be stored for a long time, and not easy to deteriorate.
5. Purity of strain: The liquid strain in the closed container is screened and tested by multiple processes, so the purity is high. Solid strains are very easy to cause contamination due to frequent expansion and transfer of generations.
6. Technical and equipment requirements: liquid strains require professional operators and high requirements for hardware equipment.
7. Observation of strains: liquid strains can be taken out at any time for testing, while solid strains are not easy to observe directly.
In large scale production fermentation, it is more appropriate to have liquid strains if the efficiency of the production cycle is considered.