Microporous membrane filtration and sterilization experiment
Microporous membrane filtration and sterilization experiment
Filtration is the mechanical removal of bacteria from liquids or gases. According to different needs to choose different filter and filter plate materials. The biggest advantage of this method of sterilization is that it can not destroy the chemical composition of the various substances in the solution, but because of the limited amount of filtration, so it is generally only applicable to the filtration and sterilization of small quantities of solutions in the laboratory, and the filtration of large quantities of solutions, such as bacteriological examination of water, see the membrane method of determining coliforms in water experiments. Source: Laboratory Microbiology (Third Edition).
Operation method
basic program
Principle
Microporous membrane filter is composed of upper and lower two plastic cover boxes with outlet and inlet connecting devices, the outlet can be connected to a needle, the inlet can be connected to a syringe, the use of the filter membrane into the two plastic cover boxes between the tightening of the cover box, when the solution is injected from the syringe into the filter, the filter will be a variety of microorganisms to stay in the top of the microporous filter membrane, so as to achieve the purpose of sterilization. According to the amount of solution to be decontaminated, different sizes of filters can be used.
Materials and Instruments
Broth peptone plates Move 1. Assembly and sterilization Put the 0.22 μm pore size membrane into a clean plastic filter, screw it tightly and flatten it, then pack it and sterilize it for use (0.1 MPa, 121.5℃ for 20 min). 2. Connection Connect the inlet of the sterilized filter to a syringe containing the solution to be filtered (2% glucose solution) in a sterile manner, connect the needle to the outlet and insert it into a sterile test tube with a rubber stopper under aseptic conditions. 3. Filter Press The solution to be filtered from the syringe is squeezed slowly under pressure and filtered into a sterile test tube. 4. Aseptic Check Pipette 0.1 ml of sterile filtrate onto a broth peptone plate, spread evenly, and incubate at 37℃ for 24 hours to check for bacterial growth. 5. Cleaning Dispose of the microporous membrane on the plastic filter, clean the plastic filter and replace it with a new one, assemble and wrap it, then sterilize it for use. Caveat 1. When pressing filtration, the force should be appropriate, not too fierce and too fast, so as to avoid bacteria being squeezed through the filter membrane. 2. The whole process should be operated strictly aseptically under sterile conditions to prevent contamination. Osmosis should be avoided at the preparation connection during filtration. For more product details, please visit Aladdin Scientific website.
2% dextrose solution
Syringe Microporous membrane filter 0.22μm membrane Sterile test tube Tweezers Glass spatula