Protein recovery concentration

Membrane-retained components are collectively called concentrate or retentate. Materials permeating the membrane are called filtrate, ultrafiltrate, or permeate. It is the objective of ultrafiltration to recover or concentrate particular species in the retentate (eg, latex concentration, pigment recovery, protein recovery from cheese and casein wheys, and concentration of proteins for biopharmaceuticals) or to produce a purified permeate (eg, sewage treatment, production of sterile water or antibiotics, etc). Diafiltration is a specific ultrafiltration process in which the retentate is further purified or the permeable sohds are extracted further by the addition of water or, in the case of proteins, buffer to the retentate. 

Adsorption in expanded or fluidised beds is now widely adopted for the direct recovery of protein products from particulate feedstocks. As an integrative protein recovery operation it circumvents process bottlenecks encountered with the solid liquid separation required upstream of fixed bed adsorption, while achieving considerable concentration and primary... 

The tissue surrogates described here clearly represent a simplification of real FFPE tissues. However, they represent a useful and efficient construct for the evaluation and optimization of tissue extraction conditions for proteomic studies. More informative studies will likely be realized by using more complex tissue surrogates, which can be created by incorporating additional proteins into lysozyme solutions. Tissue surrogates comprised of up to five proteins have been successfully analyzed by MS (Fowler, unpublished data). Additionally, RNA, DNA, lipids, or carbohydrates can be added at nanomolar to millimolar concentrations to increase the complexity of the model system to better mimic whole tissue. The use of these more complex tissue surrogates should facilitate the development of protein recovery protocols optimal for proteomic investigation. 

Nguyen, N. Y., DiFonzo, J, and Chrambach, A (1980) Protein recovery from gel slices by steady-state stacking an apparatus for the simultaneous extraction and concentration of ten samples. Anal Biochem. 106,78-91. 

Integrative protein recovery operations are supposed to tolerate particle-containing biological suspensions as initial feedstock and to deliver a clarified product concentrate which can be transferred to further purification steps. Ideally, a first fractionation of the protein matrix contained in the feed is performed as well, thus combining clarification, concentration, and capture in a single process step. 

Chlor-alkali production Electrochemical synthesis Water-organic liquid separation Organic liquid mixture separaion Fermentation products recovery and purification Cell harvesting, virus and antibody concentration Protein desalting, concentration and fractionation Blood processing, including artificial kidney Isolation, concentration, and identification of solutes and particulates... 

The recovery of whole cells is best explained by the manufacturing procedure for baker s yeast. This process is almost identical to the early stage of protein recovery, except that the final product is the cell instead of the filtrate. After fermentation, the cells are spun out with a centrifuge, washed with water, and recentrifuged to yield a yeast cream with a solids concentration of approximately 18 percent. Cream yeast can be loaded directly into tanker trucks and delivered to customers equipped with an appropriate cream yeast handling system. Alternatively, the yeast cream can be pumped to a plate and frame filter press or an RDVF and dewatered to a cakelike consistency with 30-32 percent yeast solids content. The press cake yeast is crumbled into pieces and packed or spray-dried for dry products. After packaging, the yeast is ready for shipping to retail. 

Protein recovery and concentration are other major applications for inorganic membranes in the food processing area. 

These results demonstrated the feasibility of EDBM for whey protein separation and the influence of the initial protein concentration on the purity and yield of the separated fraction. At 5% WPI initial concentration, this technology allowed the separation of 98% pure (3-lg fraction with a 44% recovery yield, while at 10% WPI initial concentration a (3-lg-enriched fraction was produced containing 97.3% of (3-lg and 2.7% a-la, for a 98% total protein purity. The 10% protein concentration seems to be the best level for electrodialytic parameters and protein recovery. Furthermore, EDBM of a 10% WPI solution, by precipitation of 53.4% of the (3-lg, allowed the production of an a-la-enriched fraction in the supernatant. Since the best pH to precipitate (3-lg was demonstrated to be pH 4.65 [21], and that the protein yield increases with an increase in initial protein concentration in the solution, it was expected that electroacidilication of a 20% WPI solution to pH 4.65 would allow the highest precipitation yield. However, the limiting factor of such a process at 20% was the low conductivity of the protein solution at pH 5.0. 

Three basic quantities are defined to describe membrane performance. Flux is the permeate flow rate normalized to total membrane filter area. For protein recovery in the cell separation step, instantaneous protein transmission can be measured by determining enzyme concentration simultaneously on the retentate and permeate sides of the filter during cell concentration. Percent transmission is calculated as ... 

Figures 5(a) and 5(b) show the simulated breakthrough curves of both total protein and HSV-1 respectively. It should be noticed that the dimensionless time scales in these two figures differ by four orders of magnitude. The breakpoint of HSV-1 is the operating endpoint at which the effluent from the adsorption column can no longer meet the desired sterilization criterion. Since the HSV-1 has a much higher affinity to the bead surface, the breakpoint of HSV-1 appears much later than that of the total protein. To optimize the protein recovery, one should improve the design of the bead surface (better selectivity, higher loading capacity), size, and operating parameters of the filter to further delay the breakpoint of the virus elution. A stochastic approach to model the removal process may be more appropriate in low concentrations of viruses.

Cross-flow filtration (CFF) also known as tangential flow filtration is not of recent origin. It began with the development of reverse osmosis (RO) more than three decades ago. Industrial RO processes include desalting of sea water and brackish water, and recovery and purification of some fermentation products. The cross-flow membrane filtration technique was next applied to the concentration and fractionation of macromolecules commonly recognized as ultrafiltration (UF) in the late 1960 s. Major UF applications include electrocoat paint recovery, enzyme and protein recovery and pyrogen removal. 

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