METHODS FOR THE HARVESTING OF CELL CULTURES

1 - 24 . (canceled)

25 . A method of harvesting a protein from a cell culture comprising:

(a) providing a portion of the cell culture;

(b) performing disk-stack centrifugation on the cell culture to obtain a centrate comprising the protein;

(c) visualizing the centrate using imaging technology to confirm at least a reduced number of particles in the centrate relative to the number of particles in the cell culture prior to centrifugation; and

(d) depth filtering the centrate to obtain a filtrate comprising the protein,

thereby harvesting the protein from the cell culture,

wherein the centrifugation step is performed at a flow rate/equivalent settling area (Q/Σ) ratio that separates cells and cellular debris from the centrate with a reduced number of particles, and wherein the Q/Σ ratio has been determined by:

(i) performing a design of experiment (DOE) statistical analysis on a centrifugation step employing x input parameters;

(ii) obtaining samples from the centrate of the centrifugation step for each DOE statistical analysis;

(iii) analyzing the samples for y output parameters;

(iv) employing a statistical analysis to generate the Q/Σ ratio;

wherein

x is 1-10; and

y is 1-10;

and wherein the imaging technology comprises a charge-coupled device (CCD)-sensor unit or a complementary metal oxide semi-conductor (CMOS)-sensor unit.

26 . The method of claim 25 , wherein the cell culture is a bacterial cell culture, an insect cell culture or a mammalian cell culture.

27 . The method of claim 25 , wherein the cell culture is a mammalian cell culture.

28 . The method of claim 27 , wherein the mammalian cell culture is comprised of CHO cells or NS0 cells.

29 . The method of claim 25 , wherein x is 1-5.

30 . The method of claim 29 , wherein the input parameters comprise:

(i) Q, flow rate;

(ii) g, relative centrifugal force (RCF) of the centrifuge unit employed; and

optionally one or more of:

(iii) cell viability of the cell culture;

(iv) total cell count; and

(v) percent solids by volume.

31 . The method of claim 29 , wherein the input parameters comprise:

(i) Q, flow rate

(ii) g, relative centrifugal force (RCF) of the centrifuge unit employed; and

(iii) cell viability of the cell culture.

32 . The method of claim 25 , wherein y is 1-5.

33 . The method of claim 25 , wherein the imaging technology comprises a CCD-sensor unit.

34 . The method of claim 33 , wherein the CCD-sensor unit is in-line and capable of analyzing samples during operation of the centrifugation step.

35 . The method of claim 25 , wherein the output parameters comprise:

(i) the number of particles per frame; and optionally one or more of:

(ii) the average chord length of the particles;

(iii) the minimum centroid diameter of the particles;

(iv) the equivalent circular diameter of the particles;

(v) the statistical distribution of particle size versus the number of particles at said size; and

(vi) turbidity.

36 . The method of claim 35 , wherein output parameters (i) and (ii)-(vi) if used are measured by a CCD-sensor unit.

37 . A method of harvesting a protein from an industrial scale cell culture comprising:

(a) providing a portion of the cell culture;

(b) performing disk-stack centrifugation on the cell culture to obtain a centrate comprising the protein;

(c) visualizing the centrate using imaging technology to confirm at least a reduced number of particles in the centrate relative to the number of particles in the cell culture prior to centrifugation; and

(d) depth filtering the centrate to obtain a filtrate comprising the protein,

thereby harvesting the protein from the cell culture,

wherein the centrifugation step is performed at a Q new /Σ new ratio that separates cells and cellular debris from the centrate with a reduced number of particles, and

wherein the Q new /Σ new ratio has been determined by:

(i) determining the value of Q old using a lab-scale depth filtration device;

(ii) performing a design of experiment (DOE) statistical analysis on a lab-scale centrifugation step employing x input parameters;

(iii) obtaining samples from the centrate of the centrifugation step for each DOE statistical analysis;

(iv) analyzing the samples for y output parameters;

(v) employing a statistical analysis to generate the Q old /Σ old ratio for the lab-scale centrifugation step;

(vi) determining the value of Q new using an industrial scale depth filtration device; and

(vii) determining the value of Σ new using equation (1);

wherein

x is 1-10; and

y is 1-10;

and wherein the imaging technology comprises a charge-coupled device (CCD)-sensor unit or a complementary metal oxide semi-conductor (CMOS)-sensor unit.

38 . The method of claim 37 , wherein the cell culture is a bacterial cell culture, an insect cell culture or a mammalian cell culture.

39 . The method of claim 37 , wherein the cell culture is a mammalian cell culture.

40 . The method of claim 39 , wherein the mammalian cell culture is comprised of CHO cells or NS0 cells.

41 . The method of claim 37 , wherein x is 1-5.

42 . The method of claim 37 , wherein the input parameters comprise:

(i) Q, flow rate;

(ii) g, relative centrifugal force (RCF) of the centrifuge unit employed; and

optionally one or more of:

(iii) cell viability of the cell culture;

(iv) total cell count; and

(v) percent solids by volume.

43 . The method of claim 37 , wherein the input parameters comprise:

(i) Q, flow rate;

(ii) g, relative centrifugal force (RCF) of the centrifuge unit employed; and

(iii) cell viability of the cell culture.

44 . The method of claim 37 , wherein y is 1-5.

45 . The method of claim 37 , wherein the imaging technology comprises a CCD-sensor unit.

46 . The method of claim 45 , wherein the CCD-sensor unit is in-line and capable of analyzing samples during operation of the centrifugation step.

47 . The method of claim 37 , wherein the output parameters comprise:

(i) the number of particles per frame; and optionally one or more of:

(ii) the average chord length of the particles;

(iii) the minimum centroid diameter of the particles;

(iv) the equivalent circular diameter of the particles;

(v) the statistical distribution of particle size versus the number of particles at said size; and

(vi) turbidity.

48 . The method of claim 47 , wherein output parameters (i) and (ii)-(iv) if used are measured by a CCD-sensor unit.