两株耐铅镉菌株的分离筛选及铅镉去除性能研究

Isolation,Screening and Performance Study on Lead and Cadmium Removal of Two Pb-Cd Tolerant Strains

从尾矿土壤中分离筛选到了7株对铅镉具有双耐性的细菌菌株,其中G-1、G-2的耐受性高于其他菌株,G-1可分别耐受4000 mg·L^-1、500 mg·L^-1的铅镉,G-2可分别耐受4000 mg·L^-1、400 mg·L^-1的铅镉,16S rRNA基因序列初步鉴定G-1为芽孢杆菌属(Bacillus sp.),G-2为克雷伯菌属(Klebsiella sp.).以G-1、G-2为供试菌株,研究环境条件对其去除液体中铅镉离子的影响,结果显示,菌株G-1去除铅镉的最佳条件是温度32℃、pH为7、NaCl浓度4%、接种量2%,该条件下铅镉去除率分别为91.32%、80.66%;菌株G-2去除铅镉的最佳条件为32℃、pH为8,NaCl浓度4%、接种量2%,去除率分别达到了99.44%、72.89%.研究结果表明,两株菌株都对铅镉具有较高的耐受性,可期为微生物或微生物联合植物修复重金属污染土壤提供重要的微生物种质资源.

Seven lead and cadmium-resistant bacteria strains were obtained from the tailings soil.Among them,G-1 and G-2 are more resistant than other strains,and G-1 can tolerate Pb and Cd of 4000 mg·L^-1 and 500 mg·L^-1 respectively.G-2 can tolerate Pb and Cd of 4000 mg·L^-1 and 400 mg·L^-1 respectively.They were identified as Bacillus sp.and Klebsiella sp.respectively by 16S rRNA gene sequence.G-1 and G-2 were used as further strains to study the influence of environmental conditions on the removal of Pb^2+and Cd^2+from the liquid.The results showed that the best conditions for the removal of Pb^2+and Cd^2+by strain G-1 were the temperature of 32℃,pH of 7,NaCl concentration of 4%,and inoculation amount of 2%.Under these conditions,the removal rates of Pb^2+and Cd^2+were 91.32%,80.66%respectively.Strain G-2 has the highest Pb^2+and Cd^2+removal rate of 99.44%and 72.89%respectively under the condition of 32℃,pH of 8,4%NaCl concentration,and 2%inoculum.Both strains have a high tolerance to Pb and Cd and can be expected to provide important microbial resources for the remediation of heavy metal contaminated soil by microbes or microbes combined with phytoremediation methods.