Interactions Between Cells of Sulfobacillus thermosulfidooxidans and Leptospirillum ferriphilum During Pyrite Bioleaching

Abstract

Sulfobacillus and Leptospirillum occur frequently in leaching systems. Here we investigated the effects of cells of L. ferriphilum on biofilm formation and leaching performance by S. thermosulfidooxidans. The effects were caused by the presence of L. ferriphilum or an addition of pyrite leach liquor from L. ferriphilum. Data show that the number of attached S. thermosulfidooxidans on pyrite increases, if the pyrite had been pre-colonized by living biofilms of L. ferriphilum, while it decreases if the pre-colonized biofilms had been inactivated. Coaggregation between S. thermosulfidooxidans and L. ferriphilum occurs during the dual-species biofilm formation, but different effects on bioleaching were noted, if the preculture of L. ferriphilum had been different. If L. ferriphilum had been pre-colonized on a pyrite, significantly negative effect was shown. However, if the two species were simultaneously inoculated into a sterile leaching system, the bioleaching efficiency was better than that of a pure culture of S. thermosulfidooxidans. The effect might be related to a metabolic preference of S. thermosulfidooxidans. If S. thermosulfidooxidans performed leaching in a filtered pyrite leachate from L. ferriphilum, the cells preferred to oxidize RISCs instead of ferrous ion and the number of attached cells decreased compared with the control. This study gives an indication that in a short-term multi-species leaching system the role of S. thermosufidooxidans may be related to the time of its introduction.

Bioleaching and Electrochemical Behavior of Chalcopyrite by a Mixed Culture at Low Temperature

“…For instance, L. ferriphilum enhanced the adhesion of Sb. thermosulfidooxidans to pyrite ( Li et al, 2020 ). On the contrary, bioleaching using mixed cultures at low temperatures was scarcely studied.…”

Sulfobacillus harzensis sp. nov., an acidophilic bacterium inhabiting mine tailings from a polymetallic mine

“…Cells of species of the genus Sulfobacillus can obtain energy by oxidizing ferrous iron, elemental sulfur and sulfide minerals in the presence of small amounts of yeast extract. Owing to the sulfur- and iron-oxidizing activity, microorganisms of this genus are important in the oxidative dissolution of sulfide minerals [12–15]. For instance, the weak iron oxidation ability of S.…”

“…Cells of species of the genus Sulfobacillus can obtain energy by oxidizing ferrous iron, elemental sulfur and sulfide minerals in the presence of small amounts of yeast extract. Owing to the sulfur-and ironoxidizing activity, microorganisms of this genus are important in the oxidative dissolution of sulfide minerals [12][13][14][15]. For instance, the weak iron oxidation ability of S. thermosulfidooxidans improves chalcopyrite bioleaching by maintaining a favourable redox potential [16]; and chalcopyrite leaching by S. thermosulfidooxidans was not inhibited in the presence of 200 mM NaCl [17].…”

Contributions of Microbial “Contact Leaching” to Pyrite Oxidation under Different Controlled Redox Potentials

“…Chemotaxis response and wetting behavior of the substrates can affect the microbial adsorption significantly. Pre-colonized species can affect latter attachment, and cell attachment performance is varied even between mixed cultures and pure cultures alone [21,22]. The function of the attached microbes is very critical to study.…”