Fermentors for Animal Cell Culture

For continuous enzyme reactors (i.e., CSTR for enzyme reactions), we have Equations 12.31 and 12.32  

Animal cells, and in particular mammalian cells, are cultured on industrial scale to produce vaccines, interferons, monoclonal antibodies for diagnostic and therapeutic uses, among others materials. 

One method of culturing anchorage-dependent tissue cells is to use a bed of packings, on the surface of which the cells grow and through which the culture medium can be passed. Hollow fibers can also be used in this role here, as the medium is passed through either the inside or outside of the hollow fibers, the cells grow on the other side. These systems have been used to culture liver cells to create a bioartificial liver (see Section 14.4.2). 

1 A fermentation broth contained in a batch-operated, stirred-tank fermentor, with a diameter D of 1.5 m, equipped with a flat-blade turbine with a diameter of 0.5 m, is rotated at a speed N= 3 s. The broth temperature is maintained at 30 °C with cooling water at 15 °C, which flows through a stainless steel helical coil, with an outside diameter of 40 mm and a thickness of 5 mm. The heat evolution by biochemical reactions is 2.5 x 104kJ h 1, and dissipation of mechanical energy input by the stirrer is 3.5 kW. Physical properties of the broth at 30 °C density p = 1,050 kg m , viscosity p — 0.004 Pa s, specific heat cp = 4.2kj kg-1 °C-1, thermal conductivity k = 2.1 kj h 1 m 1 °C 1. The thermal conductivity of stainless steel is 55kJh-1m-loC-1. 

Calculate the total length of the helical stainless steel coil that should be installed for the fermentor to function adequately. 

2 Estimate the liquid-phase volumetric coefficient of oxygen transfer for a stirred-tank fermentor with a diameter of 1.8 m, containing a viscous non-Newtonian broth, with consistency index K = 0.39, flow behavior index n = 0.74, 

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Commercial manufacturing operations in biotechnology usually employ bioreactors or fermentors for product expression. In this discussion, the term fermentor will refer to bacterial or fungal processes and the term bioreactor to animal cell cultures. While extensive description of the operation... 

For an animal cell culture, satisfactory results were obtained with a pilot fermentor, 0.3 m in diameter, with a liquid height of 0.3 m (clear liquid), at a rotational impeller speed N of 1.0 s (impeller diameter 0.1 m) and an air rate (30 °C) of 0.02 m min. The density and viscosity of the broth are 1020kg rn and 0.002 Pa s, respectively. The value can be correlated by Equation 7.36b. When k a is used as the scale-up criterion, and the allowable impeller tip speed is 0.5 m s , estimate the maximum diameter of a geometrically similar stirred tank. 

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