Air-lift fermenter

FIG. 24-4 Air-lift fermenters (a) Concentric cylinder (h) external recycle. 

There is only one choice for the antibiotic production process the synthesis of benzyl-penicillin (penicillin G, originally known as penicillin ). This, the most renowned antibiotic and the first one have been manufactured in bulk, is still universally prescribed.5 Although originally made by surface liquid culture, penicillin G is now produced by air-lift fermentation under aerated conditions. 

Decolorization of polymeric dyes Poly R-478 (polyanthraquinone-based) and Poly S-l 19 (azo dye) by immobibzed white rot fungus Crysosporium lignorum CL1 on circular plastic packing material in 2L air-lift fermenter was studied by Buckley and Dobson [47]. They also examined the relationship between polymeric dye decolorization and the production of LiP and MnP activity in its statistically growth... 

Figure 5.9 Design of a generalized microbial cell fermentation vessel (a) and an animal cell bioreactor (b). Animal cell bioreactors display several structural differences compared with microbial fermentation vessels. Note in particular (i) the use of a marine-type impeller (some animal cell bioreactors-air lift fermenters-are devoid of impellers and use sparging of air-gas as the only means of media agitation) (ii) the absence of baffles (iii) curved internal surfaces at the bioreactor base. These modifications aim to minimize damage to the fragile animal cells during culture. Note that various additional bioreactor configurations are also commercially available. Reprinted with permission from Proteins Biochemistry and Biotechnology (2002), J. Wiley Sons...

Your boss asked you to study the possibility of using an air-lift fermenter as a replacement since it has many advantages. What is your recommendation ... 

FIG. 19-32 Some examples of fermenters. (1) Conventional batch fermenter. (2) Air lift fermenters (a) Concentric cylinder or bubble column with draft tube (b) external recycle. (3) Rotating fermenter. (4) Horizontal fermenter. (5) Deep-shaft fermenter. (6) Flash-pot fermenter. 

Air coming in the bottom provides mixing for most small chemostats, referred to as air-lift fermenters. Spargers should never be used since the small bubbles remove too much C02 and the pores tend to become clogged. Otherwise, the chemostat is stirred with a magnetic stir bar or paddles. The stir bar requires that the chemostat have a flat bottom and be set on a magnetic stirrer, whereas the paddles are driven from the top. Anaerobic chemostats are mixed mechanically with either stir bars or paddles. 

The need for highly cost-efficient oxygen transfer in fermentations such as those with hydrocarbon feedstocks has led to air-lift fermenters as shown in Fig. 24-4. The world s largest industrial fermenter was... 

With the cone for a continuous flow rate of perfusion, the flow rate in the column is inversely proportional to the square of the radius of the cone at any given position. If the ratio of the radii of the inlet and outlet is 1 10 and the flow rate of the outlet is 1/100 of the inlet flow rate, then the separation efficiency of the supernatant fluid and suspended cells are improved. As shown in Fig. 13, the jacket type sedimentary system allows easy control of the temperature for separating the static supernatant from the cells. This jacket method was applied to an air-lift fermenter since it had not been done in an air-lift perfusion culture. According to Katinger et al., air-lift methods have smaller shear forces than impeller type agitation. However, in perfusion culture, comparable maximum cell densities were obtained using all three types of fermenters. 

Fermentation carried out in air lift fermenter Fermentation medium containing corn starch as carbon source... 

With the 20-1 air-lift fermenter, Davies et al. (1990) found that as the OUR was decreased so the proportions of oleic acid and linoleic acid decreased in accordance with prediction. The stearic acid content of the lipid was then increased by 50% simultaneously the content of the other saturated fatty acid, palmitic acid, also increased by over 50%. These results were then successfully repeated using a 500-1 fermenter (Table 9.6). 

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