Nutrient feed tanks

Essential equipment to a productive fermentation department are sterilizable tanks for nutrient feeds. Multiproduct plants usually require several different sizes of feed tanks (i) a small volume to be transferred once 

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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. 

The batch experiment had neither incoming fresh media nor any product stream leaving the fermentation vessel. A complete experimental set up with a B. Braun Biostat, is shown in the above laboratory experimental set up. The continuous flow of media requires a feed tank and product reservoir. The batch process has many disadvantages such as substrate and product inhibition, whereas in the continuous process the fresh nutrients may remove any toxic by-product formed. 

A 50,000-gal tank was installed adjacent to the test area. This tank was equipped with an aerator, nutrient feed equipment, and a submersible discharge pump. The physical layout of this system was very similar to that shown in Figure 12.11. 

The operation of fermenters is basically the same regardless of size, but seed fermenters usually do not have sterile anti-foam and nutrient feeds piped to the tanks as the main fermenters have. Therefore, foaming in the seed fermenters can lead to infection, which is one of the reasons they need more attention. Careful inoculation procedures, sampling and sterilizing the transfer lines from the seed fermenter require alert personnel. Careful attention to these details is more important than the proximity of the seed and main fermenters. 

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... 

Continuous reactors (Fig. 2) have both a continuous feed of nutrients and withdrawal of cells and product. The ideal continuous reactor is a stirred tank (CSTR) where the system is perfectly mixed and pH,... 

The goal of the research we report here was to determine whether the specific growth rate of predatory amoebae of the cellular slime mould Dictyostelium discoideum feeding on the gut bacteria, Escherichia coli was dependent upon prey density alone or upon the ratio of prey to predator. Two experimental systems were employed, both based on the chemostat type of continuous culture. A chemostat is a continuously stirred tank reactor in which microorganisms grow in a homogeneous environment and are supplied with nutrient solution at the same volumetric rate at... 

Contamination comes in after 24 hours] air supply/nutrient recharges/antifoam feed/loss of pressure during the run/lumps in the media/media blowbacks. [Contamination] [stock culture contaminated] /[raw materials contaminated] / [inoculation tank contaminated] /[ fermenter contaminated] /[incorrect proce-dures] /[ faulty maintenance] /[contamination by bacteriophage]. ... 

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