Study On The Adsorption Behavior Of The Insecticidal Protein From Bacillus Thuringiensis Onto Superifne Mineral Surface

Bacillus thuringiensis (Bt) is currently the largest produced and the most widely usedmicrobial insecticides,whose security problem has also been attention with the extensiveplanted of Bt transgenic crop.It is found that the toxin Bt transgenic crop released can beeasily absorbed by soil and mineral particles while capacity determined by soil types.Thepaper studies the adsorption and desorption characteristics of Bt insecticidal proteins on fivekinds of superfine mineral surface and the the effect of time,pH,temperature,metal ions on theadsorption by thermodynamics and kinetics,and the mechianism are also discussed with thepotential.The results show that Bt insecticidal protein can be adsorbed on the five kinds ofsuperfine mineral which belongs to the fast adsorption.It can be revealed from the dynamicscurve that adsorption time and quantity was straight up during the first 20min and the kineticchange trend remains unchanged after adding metal ions while the rate of adsorptionequilibrium is far greater than that without adding metal ions,thus adding metal ions canpromote the adsorption of Bt insecticidal protein and divalent metal ions is greater thanmonovalent’s.Desorption of Bt insecticidal protein on mineral decreases with protein mineral initialadsorption ratio, while the temperature rising, the addition of 1mmol·L-1Mg2 +desorptionrate has decreased and the changes of proportion protein between mineral do not affectdifferent desorption agent’s desorption laws. It is existence of lag phenomenon betweenadsorption and desorption of Bt insecticidal protein on minerals, which the metal ions ondesorption hysteresis coefficient has great influence on its effect, and the trend determined bymineral properties. Adding metal ions can cause mineral particle’s Zeta potential valuesincreased, thern revealing the metal ions adsorption quantity increases due to promote.