Fermentation vessels temperature probes

Activities associated with bioreactors include gas/hquid contacting, on-hne sensing of concentrations, mixing, heat transfer, foam control, and feed of nutrients or reagents such as those for pH control. The workhorse of the fermentation industry is the conventional batch fermenter shown in Fig. 24-3. Not shown are ladder rungs inside the vessel, antifoam probe, antifoam system, and sensors (pH, dissolved oxygen, temperature, and the like). Note that coils may lie between baffles and the tank wall or connect to the top to minimize openings... 

There several DO probes available. Some well-known branded fermenters, like New Brunswick, Bioflo series and the B. Braun Biotstat B fermenters are equipped with a DO meter. This unit has a 2 litre fermentation vessel equipped with DO meter and pH probe, antifoam sensor and level controllers for harvesting culture. The concentration of DO in the media is a function of temperature. The higher operating temperature would decrease the level of DO. A micro-sparger is used to provide sufficient small air bubbles. The air bubbles are stabilized in the media and the liquid phase is saturated with air. The availability of oxygen is major parameter to be considered in effective microbial cell growth rate. 

Fermenter contaminated[ [inoculum tank contaminated] /inoculum line con-taminated/procedure wrong/tank dirty/air leak/leak from the coil or jacket/faulty sensors/antifoam is not sterile/dirty gaskets, bottom valve, sample line and valve, vent line valve, vacuum breaker/nutrient feed tank or line not sterile/all lines wee not up to sterilization temperature/steam condensate left in lines/the humidity of the fermenter air upstream of the sterile filter is > 90%/pH and DO probes were not deaned between runs/probe holders were not brushed and deaned with a hypochlorite or formaldehyde solution/for a previously contaminated vessel the valves and gaskets were not replaced, instrument sensors were not removed and cleaned high boiling germicide, such as sodium carbonate or sodium phosphate was not used. 

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