Downstream process, protein recovery from

The ELISA can be used for identification and quantitation of the protein product (biopharmaceutical) of interest throughout the development, production, and manufacturing process. For example, in the initial development phase, ELISAs can aid in the selection of the best cell line. In the early manufacturing steps, it can be used to identify the appropriate product-containing pools or fractions in process to be subjected to further purification. Because of the selectivity of ELISA, it is a suitable tool to select out the protein of interest from complex protein mixtures, such as cell culture fermentation media or product pools in early steps of protein recovery as well as downstream processing. Even complex mixtures do not require much sample preparation. It is important to determine... 

From a point of view of industrial protein production the number of sequential operations necessary to achieve the desired purity of a protein contributes significantly to the overall costs of the downstream process. This is on one hand due to the capital investment and amount of consumables needed for each step as well as to the individual time requirements of each operation, as labour costs are a very important factor in the calculation of process economics. Secondly the overall yield of the purification is reduced with each additional process step, originating from its inherent loss of product. Furthermore, fast primary recovery should separate the protein of interest from process conditions detrimental to its structural stability, e.g. proteases, glycosidases, or oxidizing conditions. As the performance of the purification process, expressed by its overall yield, operation time, and capital cost may contribute to up to 80% of the total production costs [2], it is evident, that a reduction of the number of sequential steps in a purification protocol may be the key to the economic success of a potential protein product [3],... 

As the ligand-protein interaction takes place at the internal surface of porous adsorbents, kinetics and equilibrium of the interaction should be independent of the interstitial voidage within an adsorbent bed. Therefore the equilibrium capacity of an adsorbent will not be influenced by different experimental configurations e.g. batch stirred tank, batch fluidized bed, frontal application to packed or fluidized beds. The major difference arises from the medium from which the protein is isolated. As fluidized beds are used for whole broth adsorption, the properties of the broth have to be considered regarding the possible influence of components which are removed in conventional primary recovery steps and therefore are not present during the initial chromatography operations in a standard downstream process. These are on one hand nucleic... 

Downstream processing steps are also important process components and have received only limited attention. In general, however, the types of downstream processes needed to extract chemicals from cell culture would be similar to the steps involved in their extraction from whole plants. But the extraction, separation and purification steps can generally use harsher conditions than those usually employed in the biotechnology industry for the recovery of protein products from recombinant microorganisms or animal cell culture. A major emphasis is needed, however, in the integration of these steps into an overall process system. 

After biological reactions have generated a product of interest, it is necessary to recover this product from a liquid mixture that typically contains several undesirable components. The treatment of any culture broth after bioreactor cultivation is known as downstream processing. Downstream processing can account for 60-80%) of the total production cost, particularly in the production of modern recombinant proteins and monoclonal antibodies. A typical downstream process requires several steps in the areas of solid-liquid separation, cell rupture, product recovery, and product purification. It is important to minimize the number of downstream processing steps required because significant product losses inevitably occur during each step.f ... 

The topic of this paper is the modeling of events occurring in the recovery of proteins and in the conditioning of the product streams for further purification using precipitation. The typical goal of downstream processing is the recovery of a desired product from a very dilute stream while minimizing the loss of the material in what is usually a multi-step separation process. Precipitation enables an early concentration of the product and can simultaneously serve to remove contaminants that would interfere with subsequent purification steps. Further, the wide variety of potential... 

The quality characteristics of the oil produced by the enzyme-assisted aqueous extraction process is comparable to that of conventional extraction procedures except in its phosphorus content (Table 12.5). The enzymatic process yields oil with less phosphorus which requires no or limited degumming. The crude oil from this process can be physically refined without further treatment (Laiho et al., 1991). Despite this improved quality of the crude oil which is an apparent cost saving in subsequent downstream processing, the enzymatic process has not been commercially exploited due to problems with yields. Considerable degree of emulsification occurs during the process. Approximately 18-25% of the available oil in the seed remains unrecovered in a standard operation. The discovery that the versatile protein, oleosin, binds approximately 20% of the oil in oil-bearing seeds (Tzen et al., 1990) has implicated this protein in the low yields associated with this process. Thus, the recoveries could be improved by the use of proteases. It has, however, been observed that successful application of proteases to improve oil recovery produces excessively bitter meals, repressing the potential utilization of the meal as feed or food. 

Abstract Natural and synthetic polyelectrolytes have acquired notable importance in recent years due to their increasing application in different areas. One of these is downstream process methods which include the recovery, separation, concentration and purification of target enzymes from their natural sources. Polyelectrolytes interact with proteins to form soluble or non-soluble complexes. The interaction is driven by experimental variables of media such as pH, protein isoelectrical value, polyelectrolyte pKa, ionic strength and the presence of salts. The concentration of polyelectrolytes necessary to precipitate a protein completely is of the order of 10 " - 10 % p/v. Precipitation of protein by PE is a novel technique integrating clarification, concentration and initial purification in a single step. This chapter presents some properties of aqueous solutions of natural and synthetic PE as a tool to use them in the protein downstream process. 

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