Fermentors construction

In the early 1970s open fermentors and the continuous fermenting systems were found to be obsolete. The batch process was going to survive, and many new fermentor constructions appeared. The cylindroconical fermentor seemed to be the preferred solution for both a single- and a combi-vessel fermentation system, ie, fermentation and lagering in the same vessel (Fig. 11). 

Industrial fermentors, as well as pipings, pipe fittings, and valves, and all parts that come into contact with the culture media and sterilized air are usually constructed from stainless steel. All ofthe inside surfaces should be smooth and easily polished in order to help maintain aseptic conditions. All fermentors (other than the glass type) must incorporate glass windows for visual observation. Naturally, all fermentors should have a variety of fluid inlets and outlets, as well as ports for sampling and instrument insertion. Live steam is often used to sterilize the inside surfaces of the fermentor, pipings, fittings, and valves. 

The advantages of the shallow-tray fermentor are the simplicity of its construction and the low investment involved. In a shallow-tray fermentor, the oxygen transfer in the solid bed occurs primarily by diffusion instead of forced convection [29]. The thickness of the solid substrate layer in the tray is, there-... 

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