Identifying microorganisms related to copper bioleaching at 35 and 50°C

ABSTRACT Bioleaching is an alternative to pyrometallurgy for the production of metals from low-grade ores containing high level of impurities, once that live pyrometallurgical methods are economically unfeasible. The quantification and identification of those microorganisms related to bioleaching is an important strategy for process control and thus metal recovery. In this regard, molecular biology is one of the main techniques utilized for such objective. This study applied PCR, RFLP and PCR-DGGE techniques to show that the microbial diversity in copper bioleaching columns under investigation is low and the temperature is important to define the species found, with predominance of Acidithiobacillus ferroxidans, at 35°C and Sulfobacillus thermosulfidooxidans at 50°C.

摘要：生物浸出（Bioleaching）可作为从高杂质低品位矿石中提取金属的替代方案，用以替代火法冶金（pyrometallurgy），鉴于传统火法冶金手段在经济上不可行。对与生物浸出过程相关的微生物进行定量分析与种类鉴定，是实现工艺管控、提升金属回收率的重要策略。在此研究方向中，分子生物学技术是达成该目标的主要手段之一。本研究采用聚合酶链式反应（PCR，Polymerase Chain Reaction）、限制性片段长度多态性（RFLP，Restriction Fragment Length Polymorphism）以及PCR-变性梯度凝胶电泳（PCR-DGGE）技术，证实所研究的铜生物浸出柱内的微生物多样性水平较低，且温度是决定菌群组成的关键因素：在35℃条件下，优势菌种为氧化亚铁硫杆菌（Acidithiobacillus ferroxidans）；在50℃条件下，则以热硫化芽孢杆菌（Sulfobacillus thermosulfidooxidans）为优势菌种。