Apparatus continuous culture

Flow cytometry [141, 142] is a technique that allows the measurement of multiple parameters on individual cells. Cells are introduced in a fluid stream to the measuring point in the apparatus. Here, the cell stream intersects a beam of light (usually from a laser). Light scattered from the beam and/or cell-associated fluorescence are collected for each cell that is analysed. Unlike the majority of spectroscopic or bulk biochemical methods it thus allows quantification of the heterogeneity of the cell sample being studied. This approach offers tremendous advantages for the study of cells in industrial processes, since it not only enables the visualisation of the distribution of a property within the population, but also can be used to determine the relationship between properties. As an example, flow cytometry has been used to determine the size, DNA content, and number of bud scars of individual cells in batch and continuous cultures of yeast [143,144]. This approach can thus provide information on the effect of the cell cycle on observed differences between cells that cannot be readily obtained by any other technique. 

Chemostat an apparatus in which organisms are maintained in continuous culture (q.v.) through continuous input of a growth-limiting nutrient. 

Research with anaerobic cultures can be in batch or continuous culture. Fed-batch anaerobic reactors are not known to us but may very well be feasible. A reliable technique for batch cultures uses serum bottles sealed with butyl rubber stoppers and crimp sealed with an aluminum cap. Anaerobic microorganisms in batch flasks are mainly cultured by Hungate s methods [7] that are widely accepted in the research community. We will not describe these techniques but will focus on the different continuous culture apparatuses that have been developed over the years. 

Metabolic modifiers are added to the fermentation media to force the biosynthetic apparatus of the cell in a certain direction.Most metabolic blocks of commercial importance, however, are created by genetic manipulation. In screening media formulations in a relatively short period of time, banks of shake flask cultivations as well as continuous culture methods are most useful. 

Fermenter studies were carried out in a New Brunswick continuous culture apparatus with 15-liter stirred fermenter jars for culture vessel and nutrient reservoirs and a 20-liter carboy for a harvest vessel. Temperature of the culture was maintained at 28°-29°C. Impeller speed was kept at 120 r.p.m. with a 3-inch diameter set of four impeller blades low in the culture, and a second impeller just above the liquid level to aid in foam control. A few drops of Dow Coming Antifoam AF at 25 mg./ml. (emulsion) were added manually as required to control foam. The rate of aeration was 1 to 3 liters per minute. Contamination through the impeller shaft port was prevented by a loose fitting sleeve through which live steam was continually passed (10). Samples taken from the fermenter were streaked on potato dextrose agar, and Bacto plate count agar, incubated for 7-10 days and inspected for contamination. 

The ER, Golgi bodies, and nuclear envelopes in cotyledon cells and cells of Chara corallina showed a marked increase in density by ZIO staining (38,39). We investigated the continuity of the Golgi apparatus into the ER of cultured tobacco protoplasts by ZIO staining (40). 

Continuous cell culture (patented) [25] Cell-expansion apparatus (patented) [26] Production of a concentrated solution from biological substances (patented) [27]... 

Scaled-up codeine production by transformed cultures of R somniferum was achieved using a rotating drum fermenter (Table 25). The yields of codeine were not economically feasible. However, the data present a possibility for the continuous production of codeine because one forth of it (79.3 pg) was detected in the culture medium. In addition, productivity might be improved by further optimization including the selection of appropriate transformed clones and culture apparatus and condition. 

An alternative, possibly better method, is the pulse feed, or continuous feed. This lessens the potential for toxicity by the compound and can take the form of daily feeds starting from inoculation or from the end of log phase. Continuous feeding can be carried out with the help of advanced and expensive fermentation apparatus or by the use of a wick, with one end in the culture and the other in the solution of substrate. Once fed, the culture is left, typically for several days, to allow reactions to take place. 

This disk, with a human ureteral explant positioned on it, was placed on the mandril of a simulated bladder apparatus, as shown in Figure 9.36. The apparatus could be filled with culture medium and held in a static nonextended state for several days. Alternatively, the simulated bladder could be slowly filled to 100% extension over a 3-hour period and emptied in 25 seconds. This filling and emptying continued for several days. 

The Porton Mobile Enclosed Chemostat (POMEC) described by Evans and Harris-Smith was the first fermentation system designed and built to enable stirred batch (20 1) and continuous (2.5 1 vessel) culture of pathogenic bacteria to be carried out without risk of escape of any aerosols released from the fermenter vessel. A specially designed and constructed culture apparatus was contained within a purpose-built Class III type cabinet constituted of glass reinforced polyester resin. The various controls and measurement indicators were panel-mounted and accessible on the exterior of the cabinet. An inclined airlock with two UV lights and a liquid disinfectant lock (dunk tank) were set into the cabinet wall to allow safe... 

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