College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China.
College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environment Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China.
J Hazard Mater. 2018 Jan 5;341:150-158. doi: 10.1016/j.jhazmat.2017.07.058. Epub 2017 Jul 25.
Genetically modified Bacillus thuringiensis (Bt) crops, which have been widely used in agricultural transgenic plants, express insecticidal Cry proteins and release the toxin into soils. Taking into consideration the environmental risk of Cry proteins, biosurfactant-rhamnolipids were applied to desorb Cry proteins from soil environment, which has not been elucidated before. Quartz crystal microbalance with dissipation (QCM-D) was used in this article to investigate the adsorption and desorption behaviors of Cry1Ac on SiO surface (model soil). Results showed that patch-controlled electrostatic attraction (PCEA) governed Cry1Ac adsorption to SiO and the solution pH or ionic strength can affect PCEA. The adsorption kinetics could be fitted by the pseudo-second-order model, and the adsorption isotherm was fitted to Langmuir model with correlation coefficients higher than 0.999. The desorption characteristics of Cry1Ac from SiO were assessed in the presence of mono-rhamnolipid, di-rhamnolipid or complex-rhamnolipid. Mono-rhamnolipid exhibited the most significant positive effect on desorption performance. With a complete removal of Cry1Ac reached when mono-rhamnolipid concentration was up to 50mgL. Additionally, the desorption was enhanced at alkaline pH range, and Cry1Ac can be completely and rapidly desorbed by rhamnolipids from SiO at ionic strength of 5×10M.
遗传改良的苏云金芽孢杆菌（Bt）作物已广泛应用于农业转基因植物，表达杀虫 Cry 蛋白并将毒素释放到土壤中。考虑到 Cry 蛋白的环境风险，生物表面活性剂鼠李糖脂被应用于从土壤环境中解吸 Cry 蛋白，这在以前尚未阐明。本文采用石英晶体微天平耗散（QCM-D）研究了 Cry1Ac 在 SiO 表面（模型土壤）上的吸附和解吸行为。结果表明，补丁控制静电吸引（PCEA）控制 Cry1Ac 对 SiO 的吸附，溶液 pH 值或离子强度会影响 PCEA。吸附动力学可用拟二级模型拟合，吸附等温线用 Langmuir 模型拟合，相关系数均高于 0.999。在单鼠李糖脂、双鼠李糖脂或复合鼠李糖脂存在的情况下，评估了 Cry1Ac 从 SiO 上的解吸特性。单鼠李糖脂对解吸性能表现出最显著的积极影响。当单鼠李糖脂浓度高达 50mgL 时，Cry1Ac 可完全去除。此外，在碱性 pH 范围内解吸增强，在离子强度为 5×10M 时，鼠李糖脂可完全且快速地从 SiO 上解吸 Cry1Ac。
