(Bio)chemistry of bacterial leaching—direct vs. indirect bioleaching

Sulfur K-edge XANES and acid volatile sulfide analyses of changes in chemical speciation of S and Fe during sequential extraction of trace metals in anoxic sludge from biogas reactors

“…4) and the AVS (Table 4) extractions revealed a partial oxidation of iron monosulfides to zero-valent S during the sequential extraction of the exchangeable fraction. Two main mechanisms have been proposed for oxidation of metal sulfides depending on the structure of the sulfide minerals and environmental conditions [37]. Table 1) in an anaerobic box.…”

Mineral CO2 sequestration by environmental biotechnological processes

“…In addition to the illustrated mechanisms, direct bacterial effects such as biofilm growth can also potentially improve the dissolution process via chelation by metabolites or oxidation-reduction reactions (Bennett et al, 2001;Castanier et al, 1999;Frey et al, 2010;Rogers & Bennett, 2004;Uroz et al, 2009). Assessing the exact role of bacteria on mineral dissolution is a challenging task because environmental factors that are altered by microbial activities and mineral dissolution can influence one another simultaneously (Sand et al, 2001;Vandevivere et al, 1994). One of the motivations for the 8 current thesis is to develop a method that can differentiate between the chemical and biological effect of microbial activity.…”

“…Fermentative conversions have been proposed to influence the silicate mineral dissolution process by indirect mechanisms including the proton-promoted mechanism, organic ligand complexation, and change of ionic strength and by direct mechanisms caused by attached microbes on the mineral surface such as acidolysis, chelation and oxidoreduction reactions (Bennett et al, 2001;Sand et al, 2001;Uroz et al, 2009). The individual effect of pH, wollastonite concentration and fermentation products (organic ligands and alcohols) on the kinetics of wollastonite dissolution was studied at 30 °C by performing a series of chemical batch experiments.…”

“…acetate), is another mechanism whereby the dissolution rate of silicate minerals can be accelerated (Pokrovsky et al 2009;Ullman et al 1996;Uroz et al 2009). In addition, it has been reported that when microbes are attached to the mineral surface they are able to influence the dissolution of silicate minerals by acidolysis, chelation or oxido-reduction reactions which are defined as direct impacts (Bennett et al 2001;Berthelin 1988;Frey et al 2010;Rogers and Bennett 2004;Sand et al 2001;Uroz et al 2009). Assessing the exact role of microbes on mineral dissolution is a challenging task since environmental factors that are altered by microbial activities and mineral dissolution can influence one another simultaneously (Sand et al 2001;Vandevivere et al 1994).…”

“…In addition, it has been reported that when microbes are attached to the mineral surface they are able to influence the dissolution of silicate minerals by acidolysis, chelation or oxido-reduction reactions which are defined as direct impacts (Bennett et al 2001;Berthelin 1988;Frey et al 2010;Rogers and Bennett 2004;Sand et al 2001;Uroz et al 2009). Assessing the exact role of microbes on mineral dissolution is a challenging task since environmental factors that are altered by microbial activities and mineral dissolution can influence one another simultaneously (Sand et al 2001;Vandevivere et al 1994). The main objective of the present study was to develop an experimental system to determine the main processes which can influence alkaline silicate mineral dissolution in an anaerobic fermentation process.…”