The core equipment for biological fermentation is a bioreactor (commonly a glass jar), which requires real-time monitoring and controlPH valueandDissolved oxygen (DO)Two key parameters, suitable for room temperature fermentation (cultivation at 30-35 ℃), the reactor can withstand sterilization at 121 ℃ for half an hour, meeting the requirements of aseptic fermentation.
Pre installation of electrodes: Before sterilization, install the pH electrode into the reactor. The interface can be K8S, S8 (without temperature) or VP (with temperature), and it should be inserted vertically during installation;
Joint protection: Wrap the electrode joint with tin foil to prevent water from entering during sterilization;
Material preparation: Fill the tank with a culture medium containing nutrients such as yeast extract, yeast powder, glucose water, etc., and do not inoculate the bacterial strains temporarily.
Dissolved oxygen calibration: After sterilization, turn on the ventilation and stirring, adjust to the appropriate speed, and complete 100% dissolved oxygen calibration on the instrument (calibrated before pH electrode sterilization);
PH adjustment: After sterilization, the culture medium tends to be slightly acidic (usually around pH 6), and alkaline solution needs to be added to adjust it to neutral to ensure the growth environment of bacterial strains.
Aseptic inoculation: Install a flame ring at the inoculation port and ignite it. Pour in the bacterial strain and tightly cover the lid to ensure sterility before removing the flame ring;
Fermentation monitoring: During the initial stage of inoculation, the dissolved oxygen value may fluctuate (due to microbial growth requirements), and it is necessary to supplement nutrients such as sugar (most commonly) and nitrogen sources as needed; If the pH deviates during the process, acid or alkali supplementation can be done through reserved interfaces;
Equipment maintenance: Keep the reactor sealed throughout the process to avoid bacterial contamination and ensure accurate pH and dissolved oxygen data.
Electrode interface adaptation: Depending on whether temperature monitoring is required, choose VP (with temperature) or K8S/S8 (without temperature) interface;
Aseptic operation: The sterilization, inoculation, and feeding processes must be strictly sterile, such as joint tin foil protection and the use of flame rings for inoculation;
Parameter calibration: Dissolved oxygen needs to be calibrated under ventilation and agitation after sterilization, and PH needs to be adjusted to neutral after sterilization to ensure the accuracy of monitoring.