Sulfobacillus benefaciens强化中度嗜热菌群浸出铅锌硫化矿尾矿过程机制

Mechanism of Sulfobacillus benefaciens enhancing the lead⁃zinc sulfide tailings bioleaching performance by moderate thermophilic consortia

针对铅锌硫化矿尾矿生物浸出周期长和效率低的问题,本研究采用Leptospirillum ferriphilum(L.ferriphilum)和Acidithiobacillus caldus(A.caldus)等比例混合构建了中度嗜热菌群,浸出铅锌硫化矿尾矿.引入一株兼性自养铁/硫氧化微生物Sulfobacillus benefaciens(S.benefaciens),考察其对中度嗜热菌群浸出尾矿过程的影响.结果表明,中度嗜热菌群(L.ferriphilum+A.caldus)8 d Zn浸出率达到93.94%.随着S.benefaciens引入,浸出环境保持更高的氧化还原电位和微生物活性,浸出过程中Fe^(3+)浓度以及总铁浓度增加,4 d内Zn浸出速率提升了13.63%,8 d内Zn浸出率达到96.08%,S.benefaciens的加入强化了中等嗜热菌群的浸出效率.相关性分析表明多糖、蛋白质以及溶解性有机碳(DOC)与浸出过程中的溶液介质参数变化具有统计学意义上显著性和强相关性.表面官能团以及胞外聚合物(EPS)结果证实,引入S.benefaciens在浸出过程中促进菌群产生更多的蛋白质和碳水化合物,有助于提高中度嗜热菌群的浸出效率,加快浸出铅锌硫化矿尾矿中有价金属,降低其环境毒性.

To overcome the problems of long cycle and low efficiency of bioleaching the lead⁃zinc sulfide tailings,this study applied Leptospirillum ferriphilum and Acidithiobacillus caldus in equal proportion to constructed a moderate thermophilic consortia to leach lead⁃zinc sulfide.The influence of introducing a facultative autotrophic iron/sulfur⁃oxidizer Sulfobacillus benefaciens on the process of bioleaching tailings was investigated.The results showed that Zn leaching rate of by L.ferriphilum and A.caldus consortia reached 93.94%only in 8 days.With the introduction of S.benefaciens,the leaching system maintained a higher redox potential and microbial activity,and the ferric iron and total iron concentration increased during the leaching process.The relative leaching rate of Zn increased by 13.63%within 4 days,and the Zn leaching rate reached 96.08%within 8 days.Therefore,the addition of S.benefaciens enhanced the leaching efficiency of the moderate thermophilic consortia.Correlation analysis indicated that polysaccharides,protein,and dissolved organic carbon(DOC)showed a significant correlation with the changes in solution media parameters during the leaching process.Moreover,the result of surface functional groups and extracellular polymeric substances(EPS)confirmed that the introduction of S.benefaciens in the leaching process promoted the consortia to produce more proteins and carbohydrates,which could improve the leaching efficiency of moderate thermophilic bacteria,accelerated the leaching of valuable metals in lead⁃zinc sulfide tailings,and reduced its environmental toxicity.