In this study, a single-stage up-flow fixed-bed sulfidogenic bioreactor was operated for 288 days (six stages), treating mine-impacted water at different concentrations of nickel (Ni), cobalt (Co) and other associated metals. The effect of metals on the sulfate reducing activity, metal recovery, extracellular proteins and microbial diversity was evaluated. The bioreactor configuration showed a positive synergistic effect on both sulfate reducing activity and metals recovery, which could treat up to 200 mg/L Ni. Over 99% of Ni and Co, as well as over 91% of the other metals in the influent, precipitated and settled in the bioreactor regardless of the initial metal concentration. The scanning electron microscopy (SEM) analysis of the precipitates showed the presence of extracellular polymeric substances (EPS), which may have helped to agglomerate the metal sulfide precipitates increasing their ‘particle size’ from 0.1-0.5 μm to 10-100 μm. Different extracellular proteins associated to these EPS increased in abundance upon variations of the bioreactor operation. These included proteins involved in enzymatic reactions and metal binding, such as periplasmic [NiFeSe] hydrogenase, standing out when Ni and Co was added. The biofilm characterization showed the dominance of metal-tolerant SRB genera (e.g., Desulfomicrobium spp. and Desulfovibrio spp.), but also of other non-SRB, demonstrating that a higher microbial diversity may help the biofilm endure higher metal concentrations.

在这项研究中，单级上流固定床硫化生物反应器运行了288天（六个阶段），处理了不同浓度的镍（Ni），钴（Co）和其他相关金属的矿井冲击水。评估了金属对硫酸盐还原活性，金属回收率，细胞外蛋白质和微生物多样性的影响。生物反应器配置对硫酸盐还原活性和金属回收率均显示出积极的协同作用，可处理高达200 mg / L的镍。不论初始金属浓度如何，进水中超过99％的Ni和Co以及超过91％的其他金属都会沉淀并沉淀在生物反应器中。沉淀物的扫描电子显微镜（SEM）分析显示存在细胞外聚合物（EPS），这可能有助于凝聚金属硫化物沉淀，将其“粒度”从0.1-0.5μm增加到10-100μm。随着生物反应器操作的变化，与这些EPS相关的不同的细胞外蛋白大量增加。这些包括参与酶促反应和金属结合的蛋白质，例如周质[NiFeSe]氢化酶，当添加Ni和Co时脱颖而出。生物膜表征显示了耐金属SRB属的优势（例如，加入Ni和Co时脱颖而出。生物膜表征显示了耐金属SRB属的优势（例如，加入Ni和Co时脱颖而出。生物膜表征显示了耐金属SRB属的优势（例如，脱硫微生物 和Desulfovibrio spp。），以及其他非SRB的研究，表明较高的微生物多样性可能有助于生物膜忍受较高的金属浓度。