一株抗汞真菌的分离纯化及其对含汞废水治理特性的研究

The separation and purification of a mercury-resistant fungal strain and its characteristics for mercury wastewater treatment

从汞污染土壤中分离纯化一株抗汞真菌菌株GX-4,经过内转录间隔区(ITS)序列比对,GX-4与尖孢镰刀菌(Fusarium oxysporum)同源性达到99%。采用GX-4吸附去除含汞废水中的Hg^(2+),考察反应时间、Hg^(2+)初始浓度、pH和GX-4菌悬液投加量对Hg^(2+)去除率的影响,观察GX-4吸附Hg^(2+)前后的微观形态变化。结果表明,30~60min为GX-4对Hg^(2+)的快速吸附阶段,在处理Hg^(2+)初始质量浓度低于0.50mg/L的含汞废水时,出水能够达到《污水综合排放标准》(GB 8978—1996)中的限值要求;GX-4菌悬液的最佳投加量为1.0~2.0g,最佳pH为5。对吸附Hg^(2+)后的GX-4菌株进行扫描电镜观察,发现该菌能够有效吸附Hg^(2+),并将吸附在细胞壁上的Hg^(2+)转化为稳定的沉淀物。

The high mercury-resistant fungal strains GX-4 was isolated from mercury-contaminated soil. As was shown by the results of ITS sequencing data,the fungal strain shared 99% conserved sequence with Fusarium oxys- porum. Applied the obtained fungal strains GX-4 to removal the Hg2＋ in mercury-containing wastewater,the effect of reaction time,initial Hg2＋ concentration,pH and fungal dosages on Hg2＋ removal efficiency was investigated,and the morphology of fungal strain GX-4 after Hg2＋ adsorption was observed. The experimental results showed that the rap- id bio-sorption of Hg2＋ happened in 30 to 60 rain period. The effluent Hg2＋ concentration could meet the requirement of ＂National wastewater discharge standard＂ （GB 8978-1996） after bio-sorption of wastewater with lower than 0.50 mg/L Hg2＋. The maximum adsorption of Hg2＋ was observed at pH 5 and fungal dosage from 1.0 to 2.0 g. SEM ima- ges showed that GX-4 had an effective Hgz＋ bio-sorption activity and could produce precipitation structure by some unknown mechanisms.