The release of hepatitis B core antigen from Escherichia coli by batch mode bead milling

Abstract

The performance of a batch model bead mill on the release of hepatitis B core antigen (HBcAg) from Escherichia coli was investigated in this study. The operating parameters examined were impeller tip speed (8-14 m/s), biomass concentration [5-20% (w/v)] and bead loading [65-80% (v/v)]. The highest yield (24.3 mg/g cell) and rate constant (0.471 l/min) of HBcAg release were achieved at impeller tip speed of 14 m/s. However, the high-shear stress under these operating conditions caused damage of the HBcAg. The highest yield (22.7 mg/g cell) and rate constant (0.344 l/ min) of HBcAg release were observed at biomass concentration of 20% (w/v). There was no significant effect of bead loading on the performance of bead milling being observed. In conclusion, the optimal operating condition for the release of HBcAg was at bead loading of 75% (v/v), biomass concentration of 20% (w/v) and impeller tip speed of 10 m/s.

Combined effect of attrition and ultrasound on the disruption of Pseudomonas putida for the efficient release of arginine deiminase

“…In general, it can be stated that, for otherwise fixed conditions, more ADI was released from more concentrated slurries. Similar increase in protein release with increasing cellmass has been reported by Ho et al, 45 for release of hepatitis B core antigen from Escherichia coli. The presence of higher cellmass in the disruption chamber is presumed to reduce the distances between centers of neighboring cells and consequently to increase the intensity of mutual interactions of the microbial cells.…”

“…Also, higher bead loading leads to higher heat generation and higher power consumption in dyno mill. A bead loading of 80–85% in Dyno mill has been widely accepted as an optimum as previously reported in various studies …”

“…Similar increase in protein release with increasing cellmass has been reported by Ho et al ., for release of hepatitis B core antigen from Escherichia coli . The presence of higher cellmass in the disruption chamber is presumed to reduce the distances between centers of neighboring cells and consequently to increase the intensity of mutual interactions of the microbial cells . However, the increase in ADI and protein release with the increasing cellmass concentration did not share a direct relation to the concentration of the cellmass slurry (Figure A,B).…”

Effect of different operating modes and biomass concentrations on the recovery of recombinant hepatitis B core antigen from thermal-treated unclarified Escherichia coli feedstock

“…Cell disintegration was carried out using a Dyno horizontal bead-mill machine (Type Multilab, Willy A. Bachofen AG, Basel, Switzerland) with 600 ml glass chamber as described by Ho et al (2008). The disrupted cells were treated with DNAse (7 g/ml) for 1 h with gentle shaking at 25 • C. The cell homogenate (unclarified feedstock) was then thermal-treated at 60 • C for 45 min with gentle mixing as described by Ng et al (2006).…”

Purification of recombinant hepatitis B core antigen from unclarified Escherichia coli feedstock using phage-immobilized expanded bed adsorption chromatography

“…HBcAg expression was induced with isopropyl-␤-dthiogalactopyranoside (IPTG) with final concentration of 0.5 mM. The cells were then harvested with centrifugation at 3836 × g (JA 14 rotor, Beckman, Beckman Coulter, California, USA) for 15 min at 4 • C. Cell disintegration was carried out based on the method described by Ho et al [22] using a horizontal bead-mill (Type Multilab, Willy A. Bachofen AG, Basel, Switzerland).…”