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Precautions and solutions for fermentation tank sterilization

Data: 2020-11-04


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Precautions and solutions for fermentation tank sterilization

The trend of replacing solid strains with liquid strains has been recognized by everyone. Now more and more factories are beginning to use liquid strains for production. Although the production indicators of liquid strains are better than solid strains, the The risk is gradually being ignored by people. Liquid strains must undergo rigorous testing before inoculation. More importantly, once the fermenter is infected with bacteria, the cause of the infection must be analyzed and resolved as soon as possible.

The various processes and solutions that affect the fermentation tank

1. Sterilization

Bacteria caused by incomplete sterilization of the fermentor will show up within 2-3 days. The performance is that the culture solution gradually becomes turbid, the formation and growth of bacteria balls become slower, and the degree of expression of different bacteria from the exhaust smell is different. 

It must be noted that if the cultivation is a low-temperature variety, such as Flammulina velutipes, the performance time will be delayed, and there is no obvious macroscopic performance even before inoculation. Only by testing can it be determined that the bacteria have been infected.

Solution: Korean-style fermentation tank, check the sterilization pot program, pipeline, solenoid valve (pneumatic valve), temperature sensor, pressure sensor, etc. For the monomer fermentation tank, check whether the cold air is exhausted and whether the pipeline sterilization meets the standard.

If the problem cannot be resolved after investigation, it is necessary to appropriately increase the sterilization time or sterilization temperature.

2. Cooling

Bacteria infection during the cooling process is mainly due to the fact that the fermentation tank is not fed into the fermenter in time before the pressure "0" during the cooling process, resulting in negative pressure. Although the pipelines are equipped with check valves, it is important to know that the check valves are not absolute and single The possibility of failure of the valve is very high after using for a long time. 

Generally, the chance of infection caused by cooling is not high, and the time for infection to appear is later than that caused by incomplete sterilization.

Solution: Arrange a special person to be responsible for the cooling of the fermentation tank to avoid negative pressure and strengthen the daily inspection and maintenance of the fermentation tank pipe fittings.

3. Vaccination

The process of fermentation tank inoculation is the process of opening the tank to the outside world. It is the most dangerous link. When the infection caused by inoculation is severe, it will show up quickly, and it may show up in 1-2 days, mainly due to improper operation by personnel. 

If the edible fungus laminar flow hood has a reduced purification effect, it can also cause bacteria contamination.

Solution: Strengthen the operating skills of the inoculation personnel and formulate operating procedures; regularly check the purification effect of the inoculated laminar flow hood, and conduct flat-plate settlement tests on the laminar flow hood every day if necessary.

4. Air source

The period during which the contamination of the fermentor caused by the gas source is uncertain and irregular, and the severity of the contamination of the gas source also affects the performance of the contamination. In particular, the impact caused by the inflow of water from the gas source is the greatest. One of the biggest characteristics of the bacteria caused by the gas source is that the fermentation tanks of different days show the infection at the same time.

Solution: Check the quality of sterile air every day or regularly, and strengthen the inspection of sterile air system equipment. Long-term interruption of the gas source will also affect the growth of liquid bacteria, but generally does not cause bacteria infection.

5. Triangular flask strain

The impure strains of the Erlenmeyer flask will directly cause the fermentation tank to be infected. The performance period is also very early. The fastest performance will appear on the first day. 

The probability of this situation is not very large, but it must be Enough attention should be paid to the purity of the species. A qualified liquid strain technician is not only a good job of the fermenter, but also the level of making the test tube mother species and the Erlenmeyer flask.

Solution: Pay attention to and strengthen the production level of test tube mother species and Erlenmeyer flask strains, prepare standards and implement them. 

If you are not sure about the Erlenmeyer flask strains, you can empty the inoculated Erlenmeyer flasks to cultivate.

The offline sterilization fermentation tank provided by Paragon can solve the above problems to a large extent and save more manpower and material resources.