Ultrafiltration Method for Bacteria Collection in Fermentation Broth
Introduction
Utilizing the screening function of the ultrafiltration membrane, the fermentation broth is passed through the ultrafiltration membrane, so that larger bacteria and particles are retained on the membrane, and small molecular solutes and liquid phase are eluted through the membrane. The ultrafiltration method can effectively separate the bacteria and the solution, and collect relatively pure bacteria. However, the ultrafiltration method mandates specialized equipment and entails intricacy and time.
General steps for collecting bacteria by ultrafiltration
①Preparation of ultrafiltration device: select a suitable ultrafiltration device, usually including ultrafiltration membrane, membrane support and collection container. Make sure the ultrafiltration membrane and collection vessel are clean and sterile.
②Pretreatment of fermentation broth: according to actual needs, carry out necessary pretreatment on fermentation broth. For example, particulate matter or solid impurities can be removed by centrifugation and other operations to make the liquid clearer for subsequent ultrafiltration operations.
③Assembly of ultrafiltration device: install the ultrafiltration membrane in the ultrafiltration device, and ensure that the membrane support is correctly fixed and fits tightly with the ultrafiltration membrane. Place the ultrafiltration unit on the collection vessel to receive the filtrate passing through the membrane.
④Conducting the ultrafiltration operation: slowly pour the pretreated fermentation broth into the ultrafiltration device, or pass the liquid through the ultrafiltration membrane by applying pressure or vacuum force. The ultrafiltration operation needs to be careful and slow to prevent the ultrafiltration membrane from breaking or bacteria leakage.
⑤Bacteria collection: once the fermentation broth passes through the ultrafiltration membrane, the bacteria will stay on the membrane, while the small molecule solute and liquid phase will be eluted through the membrane. When the filtrate operation is completed, collect the bacteria on the ultrafiltration membrane into a clean container. ⑥Further processing of collected bacteria: the collected bacteria can be further processed according to the needs, such as freeze-drying, cryopreservation or cell crushing and extraction.
