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Fermentor
FN1 - Fermentor, New Brunswick, Model MF-214 The Microferm is a bench-scale fermentor designed for mass cultivation of microorganisms in batch fermentation and continuous culture; this research apparatus is fully instrumented for monitoring and controlling temperature, rate of agitation and aeration. Cells are cultivated in a stirred Pyrex glass fermentor fabricated for repeated autoclaving. The vessel rests on a head adapter plate so that a single MicroFerm assembly can accommodate all available fermentor vessel sizes up to 14 liters when the appropriate adapter is employed. A quick-disconnect drive coupling with twist-lock design simplifies removal of the fermentor. In MF units the impeller shaft of the conventional mechanically coupled fermentor vessel is supported by two stainless steel ball bearings mounted within a housing sealed top and bottom, which is press fitted to the head plate. A lapped mechanical seal at the lower end of the housing prevents transfer of lubricant or fermentation broth, with resultant contamination, from housing to fermentor or vice versa. Efficient agitation is achieved by ijpellers with flat stirring paddles and by four vertical baffles. The culture medium is agitated in a radical pattern, achieving uniform dispersion of constituents. Since the impellers are removable they can be positioned for different working volumes if desired. Reproducible agitation is attained by means of a precision drive mechanism with a solid-state speed controller. The drive is quiet and provides constant speed over a wide range. Impeller speed is closely regulated by an electronic feedback system, which compensates automatically for normal voltage fluctuations and viscosity changes in the culture medium. Agitation is continuously monitored on a calibrated electrical tachometer, which provides accurate speed indication. Air or other gas is metered through a pressure regulator, needle valve, flow meter and a stainless steel, glass wool packed filter. Sterile gas is fed through a sparger line with a single orifice. The orifice fitting is removable and can be replaced with an accessory ring sparger or sintered disc sparger. To minimize liquid loss and evaporation of the culture medium, effluent gas is passed through a small, water-cooled exhaust gas condenser in the fermentor head plate. Here, vapor and aerosols are condensed and returned to the culture as the gas passes through the exhaust filter. Close thermal regulation is achieved by a temperature controller that energizes an in-line immersion heater in the water circulation circuit or a solenoid valve in the cold-water inlet line. Temperature fluctuations are avoided by conditioning the recirculating water before it passes through the hollow baffles. This mixing of cool and warm water in the circulating circuit, and the rapid flow through the baffles prevents temperature surges and increases control accuracy. Our stock unit contains:
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