The results of the experiment demonstrated that the optimum conditions for immobilization were as follows: the range of optimum concentration of solution papain was 1.0-(2.0 mg/mL),pH value was 7.0 and the time for immobilization was 2 h. The maximal activity of the immobility papain was 111.1 U/g and the activity recovery of the immobility papain was 57.9%.
The β-glucanase from strain GXC of Trichoderma reesei was purified in three steps which comprised ammonium sulfate precipitation, Sephadex G-100 chromatography, and DEAE-Sephadex A-50 chromatography. The purified enzyme showed an activity increase of 14.60 fold, and an activity recovery of 6.62%.
The results were as follows: the optimum load of enzyme was 40～50mg/g carrier, crosslinking for 12h with 0.4%～0.5%glutaraldehyde at 25～30℃and pH7.5. The activity recovery of the immobilizated papain was 61.6%respectively.
When the concentration of gelatin was 150 g/L, the concentration of glutaraldehyde was 0.5%, the lactase amount was 5 g/L, pH value was 7.2 and mixing round time was 3 minutes, the result of lactase activity recovery ratio was up to 78.12%.
hydrophobic chromatography,and Sephadex G-25 Fine. The final specific activity of LDH was up to 1096.8 U/mg and the purity was 88%. 21.4-fold purification was obtained with enzymatic activity recovery of 53.9%.
The protein mass yield of rhIFNα-2b under the optimum condition was 4.2 times higher than that of dialysis refolding process. The activity recovery rate was 68.7% with the specific activity of 1.77×108IU/mg,and purity of 90%.
The studies on the immobilization of tannase indicated that when 0.1g chitosan reacted with 3% glutaraldehyde 5 ml for 4 h, then reacted with 58.4 u tannase for 4 h at 4 °C , the activity recovery of tannase was 73%.
Addition of the same concentration of polysorbate 80 to the reconstitution medium caused an increase in activity recovery for each formulation, but the overall pattern remained unchanged.
Annealing of sucrose-glycine formulations causes a small but significant decrease in activity recovery relative to unannealed controls, whereas no annealing effect is observed with sucrose-only formulations.
In a sucrose-only excipient system, activity recovery of both model proteins is about 80% and is independent of sucrose concentration over a range from 1 to 40 mg/mL.
However, the high activity recovery in the presence of detergents, as the stripping agent, suggests that they can constitute suitable replacement for the more expensive and common stripping agent of cyclodextrins.
These findings may assist the activity recovery of recombinant proteins at relatively high concentrations.