Shewanella oneidensis MR-1和Shewanella putrefaciens对V(Ⅴ)的还原及其影响因素

The reduction of V(Ⅴ) by Shewanella oneidensis MR-1 and Shewanella putrefaciens and influencing factors

在实验室模拟培养条件下,研究Shewanella oneidensis MR-1和Shewanella putrefaciens在厌氧体系中对Ⅴ(Ⅴ)的耐性试验,探讨在不同的Ⅴ(Ⅴ)浓度、接菌量、pH值和不同蒽醌-2,6-二磺酸(AQDS)浓度下对Ⅴ(Ⅴ)还原的影响,并通过扫描电镜(SEM)和X射线光电子能谱(XPS)进行表征.结果表明Ⅴ(Ⅴ)浓度低于10mg/L时对S.oneidensis MR-1和S.putrefaciens的生长影响较小,Ⅴ(Ⅴ)浓度超过20mg/L则会抑制其生长和Ⅴ(Ⅴ)的还原;随着接菌量的增加,2种微生物对Ⅴ(Ⅴ)的还原能力逐渐增强;2种微生物最适生长pH值均为7.0左右,弱碱性环境下2种微生物对Ⅴ(Ⅴ)的还原率高于弱酸性环境;添加1mmol/L AQDS会加快2种微生物对Ⅴ(Ⅴ)的还原.菌株培养3d后通过SEM分析,S.oneidensis MR-1和S.putrefaciens进行Ⅴ(Ⅴ)还原的同时也伴有少量的吸附作用.利用XPS能谱分析表明S.oneidensis MR-1和S.putrefaciens将Ⅴ(Ⅴ)还原为Ⅴ(Ⅳ).

Under the laboratory and simulated conditions,the tolerance of Shewanella oneidensis MR-1 and Shewanella putrefaciens to Ⅴ(Ⅴ)was tested with anaerobic incubation.The effects of different Ⅴ(Ⅴ)concentration,inoculated quantity,pH value and anthraquinone-2,6-disulfonate(AQDS)concentration on Ⅴ(Ⅴ)reduction were investigated.The mechanisms of Ⅴ(Ⅴ)microbial reduction were studied by scanning electron microscopy(SEM)and X-ray photoelectron spectroscopy(XPS).The results showed that Ⅴ(Ⅴ)at the concentration within 10mg/L slightly affected the growth of S.oneidensis MR-1 and S.putrefronens,while cells growth and Ⅴ(Ⅴ)reduction were inhibited when the concentration of Ⅴ(Ⅴ)was over 20mg/L.With the increasing quantity of microbial inoculation,the reduction ability of the two bacteria to Ⅴ(Ⅴ)was gradually enhanced.The optimum pH for the growth of two bacteria was about 7.0,and the reduction rate of Ⅴ(Ⅴ)in weak alkaline growth environment was higher than that in the weak acid environment.The addition of 1mmol/L AQDS could enhance the reduction of Ⅴ(Ⅴ).The SEM analysis were carried out for the bacteria after 3days incubation,which found that S.oneidensis MR-1 and S.putrefaciens reduced Ⅴ(Ⅴ),accompanied with a small amount of adsorption.The XPS energy spectrum analysis indicated that Ⅴ(Ⅴ)were reduced to Ⅴ(Ⅳ)by S.oneidensis MR-1 and S.putrefaciens.