含vgb基因的重组毕赤酵母菌对重金属离子的吸附解吸特征

酵母因为其比表面积大、密度高被广泛用于水体中重金属的吸附.本文研究比较野生毕赤酵母KM71及含有vgb基因的重组毕赤酵母KM71对重金属Ni²⁺、Cd²⁺和Pb²⁺的吸附解吸特性，并研究混合金属离子对酵母菌吸附性能的影响.不同金属离子均在2 h达到吸附解吸平衡，酵母菌对不同种类金属离子的吸附具有选择性，温度和pH变化对毕赤酵母吸附重金属影响较小.重组毕赤酵母菌对重金属的抗性更强.通过对环境因素及复合剂的优化，得到对重金属镉、镍、铅具有高效吸附性能的重组酵母菌，重组酵母菌对单元素溶液中Ni²⁺、Cd²⁺和Pb²⁺的吸附量分别为10.56、17.68和20.14 mg·g^-1，对三元金属混合溶液中的Ni²⁺、Cd²⁺和Pb²⁺的吸附量分别为8.28、9.89和19.99 mg·g^-1.通过条件优化重组毕赤酵母对Ni²⁺、Cd²⁺和 Pb²⁺的吸附率分别提高了15.14%、21.04%、18.47%，吸附量分别提高了11.26、13.43、22.90 mg·g^-1.本试验为促进酵母菌在处理重金属污染废水中的广泛应用提供了科学依据.

The adsorption and desorption characteristics of heavy metals in water by recombinant Pichia pastoris

Yeast is widely used in heavy metal adsorption in water. In this paper, the adsorption and desorption characteristics of native Pichia pastoris KM71 and recombinant P. pastoris KM71 containing vgb gene for heavy metal ions Ni²⁺, Cd²⁺ and Pb²⁺ were studied, and the effects of mixed heavy metal ions on the adsorption properties of P. pastoris KM71 were also studied. The adsorption and desorption of different metal ions by P. pastoris KM71 reached equilibrium in 2 h. P. pastoris KM71 showed selective adsorption for different kinds of metal ions, and the alternation of temperature and pH had little effect on the adsorption of heavy metal ions by P. pastoris. Recombinant P. pastoris KM71 showed better tolerance to heavy metal ions. Through the optimization of environmental factors and mixed agents, the recombinant P. pastoris KM71 with high adsorption capacity for heavy metal ions including Ni²⁺, Cd²⁺ and Pb²⁺ was obtained. The adsorption capacities of recombinant P. pastoris KM71 for Ni²⁺, Cd²⁺ and Pb²⁺ in single element solution were 10.56, 17.68 and 20.14 mg·g^-1, respectively, and the adsorption capacities for Ni²⁺, Cd²⁺ and Pb²⁺ in solution containing mixed heavy metal ions were 8.28, 9.89 and 19.99 mg·g^-1, respectively. The adsorption rate of the recombinant P. pastoris KM71 for Ni²⁺, Cd²⁺ and Pb²⁺ increased by 15.14%, 21.04% and 18.47% through the condition optimization, and the corresponding adsorption capacities for Ni²⁺, Cd²⁺ and Pb²⁺ increased by 11.26, 13.43 and 22.90 mg·g^-1, respectively. This study would lay a scientific foundation for the further application of P. pastoris in the treatment of heavy metal polluted waste water.