Purification of yeast derived HBsAg from Pichia pastoris for preparation of a DNA recombinant hepatitis B vaccine

ABSTRACT

Positive clones from Pichia pastoris strain GS115-47-4 and KM71-47-1 were grown in 1200 ml BMGY/BMMY medium into 2 liters fermentor and 50 ml innoculum with high density was added, temperature was 30oC, agitation speed was 300 rpm and pressure was 0.5 kg/cm2. The biomass was harvested after 72 h of induction in case of GS115-47-4 strain and 48 h for KM71-47-1 strain. The density was 3,9 x 109 cells/ml. After cell lysis, the total HBsAg contents were obtained approximately 30 mg in both strains. 2 consecutive isopycnic KBr gradient ultracentifugations following one rate-zonal sucrose were performed.