Effect of diurnal temperature range on bioleaching of sulfide ore by an artificial microbial consortium

• Published in: The Science of the total environment 2022-02, Vol.806, p.150234-150234, Article 150234
• Main Authors: Fang, Xiaodi, Sun, Shuiyu, Liao, Xiaojian, Li, Shoupeng, Zhou, Siyu, Gan, Qiaowei, Zeng, Liuting, Guan, Zhijie
• Format: Article
• Language: English
• Subjects: Artificial microbial consortium; Bioleaching; Diurnal temperature range; Extracellular polymeric substances; Sulfide ore
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2021.150234

Temperature is considered to be one of the main factors affecting bioleaching, but few studies have assessed the effects of diurnal temperature range (DTR) on the bioleaching process. This study investigates the effects of different bioleaching temperatures (30 and 40 °C) and DTR on the bioleaching of metal sulfide ores by microbial communities. The results showed that DTR had an obvious inhibitory effect on the bioleaching efficiency of the artificial microbial community, although this effect was mainly concentrated in the early and middle stages (0–18 days) of exposure, gradually decreasing until almost disappearing in the late stage (18–24 days). Extracellular polymeric substance (EPS) analysis showed that DTR did not change the composition of the EPS matrix (humic acid-like substances, polysaccharides and protein-like substances), but had a significant effect on the generative behavior of EPS, inhibiting the secretion of EPS during the early and middle stages of the bioleaching process. However, the continual increase in EPS secretion in the bioleaching system gradually reduced the adverse effects of DTR on mineral dissolution. X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Scanning electron microscopy- energy dispersive spectrometry (SEM-EDS) analysis of the bioleached residue showed that DTR had no obvious effect on the mineralogical characteristics of sulfide ore. Therefore, in industrial sulfide ore bioleaching applications, in order to accelerate the artificial microbial community start-up process, temperature control measures should be increased in the bioleaching process to reduce the adverse effects of DTR on mineral dissolution. [Display omitted] •The effect of diurnal temperature range (DTR) on ore dissolution was first studied.•DTR induced inhibition of the bioleaching efficiency.•DTR inhibits the initial secretion of extracellular polymeric substance (EPS).•The increased EPS (from 3.91 mg/L to 15.30 mg/L, TOC) help reduce DTR inhibition.•DTR had no obvious effect on the mineralogical characteristics.