Adsorption Thermodynamic Characteristics of Cry1Ab Toxin from Bacillus thuringiensis in Chinese Latosol

Abstract

The adsorption thermodynamics of Cry1Ab toxin of Bacillus thuringiensis (Bt) in Chinese latosol was studied. The adsorption isotherms of Cry1 Ab toxin followed Langmuir equation (R² > 0.98) and the curves belonged to L type. The adsorption increased with the increased temperature and the maximum adsorption amount between 283 and 313 K ranged from 4.50 × 10^-6 to 7.55 × 10^-6 mol g^-1. The results show that the environmental risk of Cry1Ab toxin in Chinese latosol probably enhances if temperature increases. The adsorption of Cry1Ab toxin in Chinese latosol was a spontaneous, endothermic and entropy-increasing process. The separation factor ranged from 0.1865 to 0.4682, indicating that the adsorption of Cry1Ab toxin in Chinese latosol was favourable. The adsorption energy for Cry1Ab toxin ranged from 8 to 16 kJ mol^-1, indicating that it was an ion-exchange mechanism.