低温等离子体对镍吸附细菌B8的诱变

摘要

Radiofrequency low temperature plasma was used to mutate the strain B8 which can adsorb nickel ions, and the adsorptive ability of the mutant was tested. The experiments show that the optimum mutagenic conditions of B8 by plasma are as follows: the mutation time of 3 min, the mutation power of 50~65 W, the carrier gas of N2 and the carrier gas pressure of 20 Pa. The mutant Ni12 with high adsorptive ability was screened from the mutant strains of B8 mutated under above conditions, and the nickel ion adsorption capacity of the mutant Ni12 reaches 136.7 mg⋅g−1 (dry bacteria), which is 11.7%higher than that of raw strain B8. The genetic stability of mutant Ni12 can maintain in 5 generations. The mechanism study shows that the extra cellular polymer is an important factor affecting the adsorption of nickel ions. After the formation of mutant Ni12 biofilm on the porous ceramics, from solution with nickel ion concentration of 50 mg⋅L−1, the nickel ion adsorption ratio of Ni12 reaches 86%. The result of 16S rDNA sequence analysis indicates that the mutant Ni12 is Pseudomonas cedrina. The advantage of mutagenesis of raw strain B8 by radiofrequency low temperature plasma is its high efficiency, and the inheritance of mutant strain Ni12 is stable. Therefore, it has promising prospect of using it to treat the wastewater containing nickel ions.%　　利用射频低温等离子体对吸附镍细菌B8进行诱变，并测试突变体对镍离子的吸附能力。实验结果表明，对细菌B8诱变的最佳条件是以N2为载气，诱变时间为3 min，诱变功率为50~65 W，载气气压为20 Pa；通过对该诱变条件下的突变体进行筛选，得到了对镍的吸附能力较强的突变体Ni12，其对镍离子的吸附量达到了136.7 mg⋅g−1(干菌体)，比出发菌株B8提高了11.7%，且五代内可稳定遗传；对其机理进行讨论发现胞外聚合物为吸附镍离子的主要影响因素；同时探讨以多孔陶瓷为载体，采用微生物曝气挂膜法固定突变体Ni12，对含镍离子的溶液进行处理，其吸附率可达86%；经16S rDNA序列分析表明，突变体Ni12为Pseudomonas cedrina。射频低温等离子体对细菌B8的诱变效率高，突变体Ni12对镍离子有较强的吸附性，可稳定遗传，对含镍废水的处理有良好的应用前景。