Table Table 1.

Centrifugation Performance and Product Stream Quality for Cell Harvesting, Alkaline Lysate Separation, CTAB Precipitate Recovery, and Hydrated Calcium Silicate plus Impurity Removal

	flow rate/equivalent settling area a  (L/m2/h)
% solids sedimented	whole E. coli cells	heat‐treated clarified lysate c	neutralized whole E. coli lysate c	CTAB plasmid DNA ppt with cellulose c	homogenized E. coli  b	NSO mammalian cell e
99.99	0.027 b		0.090
99.9	0.038 b		0.180
99.0	0.057 b	(0.003)	0.270	>0.16	(0.004)	0.018
	(0.039) c
	0.015 d
95.0	0.081 b	0.006		>0.16	0.010	0.065
	0.076 c
	0.032 d
fraction of solids holding space  g	0.4 b	0.2	0.5	0.1 f	0.6

^a  Users and their centrifuge suppliers are familiar with equivalent settling area (Σ) to characterize machines. The values given can simply be multiplied by the equivalent settling area in m² to give the flow rate in L h^{− 1} corresponding to the % solids sedimented in the left‐hand column. Because many biopharmaceutical plants process mammalian cells, a value is included as are values for homogenized E. coli cells with which some biopharmaceutical users will be familiar. The data are all from pilot scale intermittent discharge disk machines so that allowance for shear is inherent. Values obtained by extrapolation appear in parentheses; all others were obtained by interpolation of probability functions. ^b  Higgins et al. (54) E. coli. ^c  UCL, unpublished, for rec E. coli. ^d  UCL, unpublished for high cell density E. coli. ^e  Hutchison et al., unpublished. ^f  Dominated by cellulose, which absorbs about 10 times its weight in liquor. ^g  Packed solids capacity before breakthrough as a fraction of the total solids holding capacity.