微生物胞外聚合物特征组分影响黄铁矿分解作用的实验研究

The effects of the typical components of extracellular polymeric substances(EPS) of microorganism on the bio-decomposition of pyrite

为探讨微生物胞外聚合物(EPS)对矿物分解的影响,以查明微生物-矿物直接接触形式对硫化物分解的显著促进作用,分别采用葡萄糖、精氨酸、葡糖醛酸、柠檬酸等EPS的特征组分,配制浓度相同的系列反应溶液,与黄铁矿颗粒持续反应29d(30℃)。通过检测反应溶液中的全铁含量来近似表征黄铁矿的溶解速率,并利用扫描电子显微镜观察黄铁矿溶解前后的形貌变化。实验发现,在微生物-矿物相互作用的过程中,EPS中的部分组分,如葡糖醛酸、柠檬酸,可能起着关键的作用,而分子量相对较大的糖类和缺少化学活动性基团的葡萄糖、精氨酸等则会降低黄铁矿分解的速率,可能与其在黄铁矿表面的覆盖有关。

Extracellular polymeric substances （EPS） seem to play an important role in bioleaching. Generally,EPS consist of neutral sugars,lipids,a small amount of amino acid and some metabolites such as organic acid. In this paper,glucose,arginine,glucuronic acid and citric acid were used to study the effects of different components of EPS on the leaching of pyrite and indicate the facilitation of the direct contact between microbes and minerals on bioleaching. The iron contents of the experimental solution were measured in order to determine the dissolving rate of pyrite,and scanning electronic microscopy was employed to observe the changes of the surface characteristics of the pyrite. Some preliminary data obtained indicate that some kinds of components of EPS,such as glucuronic acid and citric acid,can promote the dissolution,while sugars and arginine suppress the decomposition,which may be attributed to their surface coating on the pyrite surfaces.