Understanding Stress Response to High-Arsenic Gold-Bearing Sulfide Concentrate in Extremely Metal-Resistant Acidophile Sulfobacillus thermotolerans

Abstract

Biooxidation of gold-bearing arsenopyrite concentrates, using acidophilic microbial communities, is among the largest commercial biohydrometallurgical processes. However, molecular mechanisms of microbial responses to sulfide raw materials have not been widely studied. The goal of this research was to gain insight into the defense strategies of the acidophilic bacterium Sulfobacillus thermotolerans, which dominates microbial communities functioning in industrial biooxidation processes at >35 °C, against the toxic effect of the high-arsenic gold-bearing sulfide concentrate. In addition to extreme metal resistance, this acidophile proved to be one of the most As-tolerant microorganisms. Comparative proteomic analysis indicated that 30 out of 33 differentially expressed proteins were upregulated in response to the ore concentrate, while the synthesis level of the functional proteins required for cell survival was not negatively affected. Despite a high level of cellular metal(loid) accumulation, no specific metal(loid)-resistant systems were regulated. Instead, several proteins involved in the metabolic pathways and stress response, including MBL fold metallo-hydrolase, sulfide:quinone oxidoreductase, and GroEL chaperonin, may play crucial roles in resistance to the sulfide ore concentrate and arsenic, in particular. This study provides the first data on the microbial responses to sulfide ore concentrates and advances our understanding of defense mechanisms against toxic compounds in acidophiles.

Unraveling the Central Role of Sulfur-Oxidizing Acidiphilium multivorum LMS in Industrial Bioprocessing of Gold-Bearing Sulfide Concentrates

“…ferrooxidans , and L. ferriphilum (72.0–85.4% a. a. similarity, 99% coverage). As mentioned above, Acidithiobacillus and Leptospirillum strains are common members of acidophilic communities in biomining operations, including the processing of gold-bearing pyrite-arsenopyrite concentrates [ 15 , 18 , 19 , 20 , 21 ]. The closest homolog of the arsenical efflux pump membrane protein ArsB was found to belong to the Gemmataceae bacterium (94% a. a. similarity, 100% coverage).…”

“…The overall response of Sb. thermotolerans cells to the toxic amounts of the gold-containing arsenopyrite concentrate was shown to involve mainly the mechanisms for resistance to arsenic [ 19 ]. The acquisition of additional arsenic resistance determinants by At.…”

“…spp., Leptospirillum ( L. ) spp., Sulfobacillus ( Sb. ) spp., Ferroplasma ( F. ) spp., and some other microorganisms [ 15 , 17 , 18 , 19 , 20 , 21 , 22 ]. The Olympiada biooxidation plant is located in the Krasnoyarsk Krai (Siberia, Russia) and has been operated by Polyus Krasnoyarsk JSC since 2001.…”

Acción bioxidativa de cultivos microbianos biolixiviantes sobre la arsenopirita

“…La biominería contempla la aplicación de distintas tecnologías y procesos hidrometalúrgicos a través del uso de microorganismos para la extracción o disolución de metales de interés económico a partir de minerales o sólidos, con la finalidad de recuperar los elementos deseados (Brierley & Le Roux, 1978;Panyushkina, et al, 2020). Múltiples microorganismos participan en los procesos de extracción de metales de interés económico a partir de yacimientos o concentrados minerales de baja ley.…”

“…La biooxidación en minerales de oro refractarios como el de la arsenopirita es un método prometedor para la recuperación del oro que puede encontrarse como partículas microscópicas, es de fácil funcionamiento con bajo costo y ecoamigable (Deng et al, 2020;Zhao et al, 2020). Su aplicación en concentrados de arsenopirita aurífera empleando microorganismos quimiolitotróficos acidófilos está considerado entre los procesos comerciales más importantes (Panyushkina et al, 2020).…”