Fermentation downstream processing

Keywords. PHA, Polyester, Fermentation, Downstream process, Economics... 

Fig. 2. The processes involved in a typical SSF process. Note that the general categories of substrate preparation, inoculum preparation, fermentation, downstream processing, and waste disposal also occur in SLR However, the need to handle solids makes SSF more complicated...

Uses Antifoam for pharmaceuticals (antiflatulence and antacid preps.), foods (esp. for foodstuffs contg. greases and fats), fermentation, downstream processes such as active ingred. extraction and solv. recovery Features Readily sterilized by heat... 

In the development of new products, optimization of the fermentation medium for titer only often ignores the consequences of the medium properties on subsequent downstream processing steps such as filtration and chromatography. It is imperative, therefore, that there be effective communication and understanding between workers on the upstream and downstream phases of the produc t development if rational trade-offs are to be made to ensure overall optimahty of the process. One example is to make the conscious decision, in collaboration with those responsible for the downstream operations, whether to produce a protein in an unfolded form or in its native folded form the purification of the aggregated unfolded proteins is simpler than that of the native protein, but the refolding process itself to obtain the product in its final form may lack scalabihty. 

Traditionally, the upstream fermentation and cell culture processes have been viewed as being distinct from the subsequent downstream processing and purification steps, and the two different sets of processes nave been optimized individually. In some instances, careful consideration of the conditions used in the fermentation process, or manipulation of the genetic makeup of the host, can simplify and even... 

The culture can be used directly for the conversion of phenylpyruvic add to resting cells L-phenylalanine. Therefore, a batch process with resting cells can be carried out, with some glucose added for maintenance (fed-batch fermentation). Another approach is to harvest the cells from the fermentation broth and to use them in a separate bioreactor in higher concentrations than the ones obtained in the cell cultivation. An advantage of the last method can be that the concentration of compounds other than L-phenylalanine is lower, so that downstream processing may be cheaper. 

Glucose limits sucdnoglycan production (ammonia limits growth). It is necessary to limit sucdnoglycan production to avoid an excessively viscous fermentation liquor which would affect mixing and subsequent downstream processing to recover exopolysaccharide. 

In downstream processing of a fermentation unit for enzyme production with a feed stream of sugar- at a concentration of 35 g-l the expected product to be recovered is a-amylase. 

When we need to remove cells from fermentation broth, sedimentation is considered as a downstream processing method. Alum, lime, polyelectrolyte are commonly used. 

After fermentation, subsequent midstream to downstream processes such as cell disruption, centrifugation, extraction and drying will be carried on for product recovery. Fig. 9 shows a white sheet of PHB obtained from fermentation of sweet sorghum juice (SSJ) by Bacillus aryahhattai. 

Downstream Processing Microfiltration plays a significant role in downstream processing of fermentation products in the pharmaceutical and bioprocessing industry. Examples are clarification of fermentation broths, sterile filtration, cell recycle in continuous fermentation, harvesting mammahan cells, cell washing, mycelia recovery, lysate recovery, enzyme purification, vaccines, and so forth. 

Production of Microbial Polyesters Fermentation and Downstream Processes... 

As summarized above, various approaches were taken to alter the PHA production or to facilitate downstream processing by employing recombinant pseudomonads. However, as in the case with recombinant R. eutropha, no study has been carried out on the high cell density culture of recombinant pseudomonads or on the scale-up of fermentation. 

Biopharm production can be divided into upstream and downstream processing (Figure 5.5). Upstream processing refers to the initial fermentation process that results in the initial generation of product, i.e. the product biosynthesis phase. Downstream processing refers to the actual purification of the protein product and generation of finished product format (i.e. filling into its final product containers,... 

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