两株重金属抗性细菌对铅镉吸附特性的比较研究

Comparative study on adsorption characteristics of lead and cadmium by two heavy metal resistant bacteria

针对目前重金属水污染现状,为探究微生物法修复重金属水污染机制,本试验以抗重金属革兰氏阴性菌Rhizobium sp.W33与革兰氏阳性菌Bacillus sp.H3为供试菌株,对不同重金属(Pb、Cd)浓度及pH条件下的菌株生长状况进行测定;比较不同状态细胞(Growing、Grown、Dead)的吸附能力;利用FTIR初步分析吸附相关官能团.结果表明:两株菌对Pb抗性较强,对Cd抗性相对较弱,最适生长pH均在6~7范围内;不同状态细胞的吸附能力大小为:Grown>Dead>Growing;随着重金属浓度的升高,Rhizobium sp.W33与Bacillus sp.H3的吸附容量逐渐增大,且对铅镉的吸附主要以胞外吸附为主,对铅有一定的胞内积累能力;FTIR分析显示菌株吸附过程中主要是—OH、—NH、—CO、—CH2官能团在生物吸附过程中发挥作用.Rhizobium sp.W33与Bacillus sp.H3表面官能团特性及整体吸附能力存在明显差异.

In view of the current situation of heavy metal water pollution,the mechanism of remediation of heavy metal water pollution by microbiological method was explored. In this study,the heavy metal resistant gram-negative bacterium（ Rhizobium sp. W33） and gram-positive bacterium（ Bacillus sp.H3） were used as test strains. The effects of pH,lead（ Pb） and cadmium（ Cd） concentrations on the growth of strains were measured; the adsorption capacity of lead and cadmium by cells（ Growing,Grown,Dead） of different states was compared; the adsorption related functional groups were preliminarily analyzed with FTIR. The results show that the strains had strong resistance to Pb compared to Cd. Moreover,the optimal growth pH was 6 ~ 7.The order of adsorption capacity of cells in different states was： Grown Dead Growing. The adsorption capacity of Rhizobium sp. W33 and Bacillus sp.H3 was gradually increased with the increase of heavy metal concentration,and the adsorption of lead and cadmium mainly focused on the extracellular adsorption,and there was a certain intracellular accumulation capacity of lead. The FTIR results show that the functional groups of —OH,—NH,—CO,—CH2 played a role in the biosorption process. The surface functional groups and the overall adsorption capacity of Rhizobium sp. W33 and Bacillus sp. H3 was significantly different.