Method and system of protein extraction

Abstract

The present invention relates to a method and a system of extracting a protein with high yield from a protein-comprising precipitate, in particular immunoglobulin, from human or non-human origins, such as blood plasma.

1 - 32 . (canceled) 
     
     
         33 . A closed system for extracting a protein of interest from a precipitate, comprising:
 (a) a first tank configured to contain the precipitate in the form of a suspension having a first dilution factor;   (b) a first filtration unit connected with the first tank and comprising a dynamic filter element, wherein the first filtration unit is configured to:
 receive the suspension from the first tank, 
 produce, using the first filtration unit, a first permeate enriched with the protein of interest 
 and a first retentate depleted of the protein of interest, and 
 return the first retentate to the first tank; 
   (c) a second tank connected with the first filtration unit and configured to receive the first permeate enriched with the protein of interest; and   (d) a second filtration unit configured to:
 concetrate the first permeate in the second tank so as to produce a second retentate enriched with the protein of interest and a second permeate depleted in the protein of interest, and 
 one or both of (i) return the second retentate to the second tank and (ii) return the second permeate to the first tank. 
   
     
     
         34 . The closed system according to  claim 33 , wherein the precipitate is an intermediate product of an alcohol fractionation process. 
     
     
         35 . The closed system according to  claim 34 , wherein the intermediate product is selected from Cohn Fraction I (Fr I), Cohn Fraction II+III (Fr II+III), Cohn Fraction I+II+III (Fr I+II+III), Kistler/Nitschmann Precipitate A (KN A), and combinations of KN A and one or more of Fr I, Fr II+III and Fr I+II+III. 
     
     
         36 . The closed system according to  claim 33 , wherein the precipitate is a culture supernatant or a fermentation product. 
     
     
         37 . The closed system according to  claim 33 , wherein the protein of interest is an immunoglobulin (Ig). 
     
     
         38 . The closed system according to  claim 33 , wherein the dynamic filter element is a dynamic cross flow filter element. 
     
     
         39 . The closed system according to  claim 38 , wherein the dynamic filter element is a rotational cross-flow filter element. 
     
     
         40 . The closed system according to  claim 39 , wherein the rotational cross-flow filter element is configured to rotate at a rotating speed from about 600 rpm to about 1200 rpm. 
     
     
         41 . The closed system according to  claim 33 , wherein the dynamic filter element is a rotating filter element comprising one or more filter discs. 
     
     
         42 . The closed system according to  claim 33 , wherein the first filtration unit is equipped with rotating filter discs comprising ceramic membranes. 
     
     
         43 . The closed system according to  claim 33 , wherein the first filtration unit is equipped with baffles configured for turbulence mixing of the content of the first filtration unit. 
     
     
         44 . The closed system according to  claim 41 , wherein the filter disks are configured to have a tangential speed of about 1 to about 7 m/sec. 
     
     
         45 . The closed system according to  claim 33 , wherein the first filtration unit comprises a pressure vessel. 
     
     
         46 . The closed system according to  claim 33 , wherein the first filtration unit is configured to maintain a temperature in the first filtration unit of 2° C. to 25° C. 
     
     
         47 . The closed system according to  claim 33 , wherein the closed system is configured to control flow velocities of the first permeate and the second permeate such that a constant product volume is maintained in the second tank. 
     
     
         48 . The closed system according to  claim 42 , wherein a transmembrane pressure across the ceramic membranes is from 0.1 bar to 2.5 bar. 
     
     
         49 . The closed system according to  claim 33 , wherein the dynamic filter element comprises a filtration membrane having an average pore size of 5 nm to 5000 nm. 
     
     
         50 . The closed system according to  claim 33 , wherein the precipitate has a total protein concentration of about 0.5% w/v to 6.5% w/v.