Steps and precautions of sterilization for empty fermentation system

Sterilization of empty fermentation system means that the air path, material path, seed tank, fermentation tank, alkali tank, and defoaming tank must be sterilized with steam before feeding in order to eliminate all bacteria and ensure the system is in a sterile state.

1.  sterilization of air pipeline

(1)  There are three-stage filtration: pre-filter, refrigeration dryer and fine filter on the air pipeline. Pre-filter and refrigeration dryer cannot be sterilized by steam. Therefore, before steaming the air line, the valve leading to the pre-filter must be closed so that the steam passes through the pressure reducing valve, the steam filter and then into the fine filter.

(2) The filter element of the sterilization filter cannot withstand high temperature and high pressure. Therefore, the steam pressure reducing valve must be adjusted at 0.13Mpa and not more than 0.15MPa.

(3) During the air path sterilization process, the exhaust valve at the lower end of the sterilization filter should be slightly opened to drain the condensed water.

(4)  The time of sterilization should last about 40 minutes. When the equipment is used for the first time or started after long-term use, it is best to use intermittent sterilization, that is, after the first-time sterilization, it will be sterilize again every 3 to 5 hours in order to eliminate Spores. 

(5) The filter after sterilization should be ventilated and dried for about 20-30 minutes, and then close the air valve. 

2. Seed tank, fermentation tank, alkali tank and defoaming tank are empty for sterilization

(1)  Seed tank, fermentation tank, alkali tank and defoaming tank are used to directly pass steam into the tank for empty sterilization. 

(2) When sterilizing, the inoculation port, exhaust valve, and material path valve on the tank should be slightly opened to allow steam to be discharged through these valves while maintaining the tank pressure at 0.13～0.15Mpa. 

(3) The sterilizing time is 30-40 minutes. In special circumstances, intermittent sterilization can be used. 

(4)  Before the seed tank, fermentation tank, alkali tank and defoaming tank are sterilizing, the water in the jacket should be drained. 

(5) After the empty tank sterilization, drain the condensed water in the tank and open the drain valve to prevent negative pressure in the tank and damage to the equipment after cooling. 

(6) When sterilizing, the dissolved oxygen and PH electrodes should be taken out in order to prolong its service life.

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