Characterization of E. coli cell disintegrates from a bead mill and high pressure homogenizers

The protein releases, the particle size distribution and the viscosity of disrupted E. coli suspensions from Dyno Mill KDL, Manton Gaulin 15 M-8TA and Microfluidizer M-110 were determined. The effects of these parameters on separation of the cell debris from the protein solution by centrifugation and by filtration were also examined. All three disintegration methods investigated give approximately the same protein and enzyme releases but considerably different physical properties of the cell disintegrates which influences centrifugation and filtration. The separation degree of biomass during centrifugation is only slightly affected by increasing degree of disruption (increasing protein releases) in the bead mill, while an increase in the degree of disruption in the two high pressure homogenizers drastically reduces the centrifugal degree of separation. However, increasing degrees of disruption result in shorter filtration times during filtration for all three disintegration methods. The results show further that the cell concentration only has a minor influence on protein releases in the Microfluidizer high-pressure homogenizer, while an increase in the biomass content reduces the separability of the cell disintegrate both in filtration and in centrifugation.