Limits...
Bioleaching genomics.

Siezen RJ, Wilson G - Microb Biotechnol (2009)

View Article: PubMed Central - PubMed

Affiliation: Kluyver Centre for Genomics of Industrial Fermentation, TI Food and Nutrition, 6700AN Wageningen, The Netherlands. r.siezen@cmbi.ru.nl

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

Bioleaching is a natural process involving acidophilic bacteria and archaea, which have the ability to either oxidize metal sulfides or to oxidize reduced inorganic sulfur compounds (RISCs) to sulfuric acid, or both (Fig.  1, left panel)... Acid mine drainage liquors were found to contain bacteria responsible for producing iron‐rich acidic waters from coal and metal mines... These reactions take place in the extracellular polysaccharide laid down by cells growing in biofilms rather than cells in a planktonic lifestyle... Biofilm formation greatly accelerates the reactions... The role of the microbes is therefore to produce sulfuric acid for proton attack and to keep the iron in the oxidized ferric state for oxidative attack on the metal... Table 1 lists examples of acidophilic prokaryotes identified in stirred‐tank mineral bioleaching and bio‐oxidation operations... Table 2 summarizes genome sequencing projects of acidophilic microbes involved in oxidation/reduction of iron and/or RISCs, many of which were isolated from bioleaching operations... The long‐awaited, complete annotated genome sequence of the mesoacidophilic A. ferrooxidans ATCC 23270 (3.0 Mb, 58.8% GC) has only recently been published... As expected, the organism was found to have a complete repertoire of genes required for a free‐living, chemolithoautotrophic lifestyle, including CO2 fixation, nucleotide and cofactor biosynthesis... In the complete genome sequence of the extremely thermoacidophilic archaeon Metallosphaera sedula (2.2 Mb, 46% GC), genes were identified for iron and sulfur oxidation, autotrophic carbon fixation, metal tolerance and adhesion... Comparative genomics with A. ferriooxidans showed that M. sedula has different respiratory electron transport chain components, as it does not appear to contain cytochromes... A classical metagenome sequencing study of a low‐complexity, acid‐mine drainage microbial biofilm, growing within a pyrite ore body, allowed the reconstruction of near‐complete genomes of the iron oxidizers Leptospirillum group II and Ferroplasma type II... Surprisingly, Acidithiobacilli have a very large number of Fe(III)‐siderphore uptake systems, but they do not make siderophores – so in conditions of higher pH 4–5, which may occur in industrial bioleaching heaps, they may scavenge the siderophores of other organisms.

Show MeSH
Diversity of alternative iron acquisition modules and putative regulatory connections in acidophiles. Light blue: ferrous iron uptake module, Violet: Ferric‐dicitrate uptake module, Orange: Ferric‐siderophore uptake module, Grey: Metalophosphate/phosphonate uptake module, Orange arrows: Regulatory connections. Reproduced from (Osorio et al., 2008a).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3815750&req=5

f3: Diversity of alternative iron acquisition modules and putative regulatory connections in acidophiles. Light blue: ferrous iron uptake module, Violet: Ferric‐dicitrate uptake module, Orange: Ferric‐siderophore uptake module, Grey: Metalophosphate/phosphonate uptake module, Orange arrows: Regulatory connections. Reproduced from (Osorio et al., 2008a).

Mentions: For instance, how do aerobic acidophiles, especially Fe(II)‐oxidizers, contend with the paradoxical hazards of iron overload and iron deficiency, each with deleterious consequences for growth? Some organisms encounter molar concentrations of iron compared with ‘normal’ conditions 10−16 M. Comparative genomics of iron management genes and Fur regulation was carried out for the same three Acidithiobacilli and for three extreme acidophilic iron oxidizers of the Leptospirillum genus (Osorio et al., 2008a,b). Significant differences in abundance and diversity or Fe‐management mechanisms are predicted in Acidithiobacilli and Leptospirilla, and may represent niche partitioning and ecological successions in a bioleaching environment (Osorio et al., 2008a) (Fig. 3). Surprisingly, Acidithiobacilli have a very large number of Fe(III)‐siderphore uptake systems, but they do not make siderophores – so in conditions of higher pH 4–5, which may occur in industrial bioleaching heaps, they may scavenge the siderophores of other organisms.


Bioleaching genomics.

Siezen RJ, Wilson G - Microb Biotechnol (2009)

Diversity of alternative iron acquisition modules and putative regulatory connections in acidophiles. Light blue: ferrous iron uptake module, Violet: Ferric‐dicitrate uptake module, Orange: Ferric‐siderophore uptake module, Grey: Metalophosphate/phosphonate uptake module, Orange arrows: Regulatory connections. Reproduced from (Osorio et al., 2008a).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3815750&req=5

f3: Diversity of alternative iron acquisition modules and putative regulatory connections in acidophiles. Light blue: ferrous iron uptake module, Violet: Ferric‐dicitrate uptake module, Orange: Ferric‐siderophore uptake module, Grey: Metalophosphate/phosphonate uptake module, Orange arrows: Regulatory connections. Reproduced from (Osorio et al., 2008a).
Mentions: For instance, how do aerobic acidophiles, especially Fe(II)‐oxidizers, contend with the paradoxical hazards of iron overload and iron deficiency, each with deleterious consequences for growth? Some organisms encounter molar concentrations of iron compared with ‘normal’ conditions 10−16 M. Comparative genomics of iron management genes and Fur regulation was carried out for the same three Acidithiobacilli and for three extreme acidophilic iron oxidizers of the Leptospirillum genus (Osorio et al., 2008a,b). Significant differences in abundance and diversity or Fe‐management mechanisms are predicted in Acidithiobacilli and Leptospirilla, and may represent niche partitioning and ecological successions in a bioleaching environment (Osorio et al., 2008a) (Fig. 3). Surprisingly, Acidithiobacilli have a very large number of Fe(III)‐siderphore uptake systems, but they do not make siderophores – so in conditions of higher pH 4–5, which may occur in industrial bioleaching heaps, they may scavenge the siderophores of other organisms.

View Article: PubMed Central - PubMed

Affiliation: Kluyver Centre for Genomics of Industrial Fermentation, TI Food and Nutrition, 6700AN Wageningen, The Netherlands. r.siezen@cmbi.ru.nl

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

Bioleaching is a natural process involving acidophilic bacteria and archaea, which have the ability to either oxidize metal sulfides or to oxidize reduced inorganic sulfur compounds (RISCs) to sulfuric acid, or both (Fig.  1, left panel)... Acid mine drainage liquors were found to contain bacteria responsible for producing iron‐rich acidic waters from coal and metal mines... These reactions take place in the extracellular polysaccharide laid down by cells growing in biofilms rather than cells in a planktonic lifestyle... Biofilm formation greatly accelerates the reactions... The role of the microbes is therefore to produce sulfuric acid for proton attack and to keep the iron in the oxidized ferric state for oxidative attack on the metal... Table 1 lists examples of acidophilic prokaryotes identified in stirred‐tank mineral bioleaching and bio‐oxidation operations... Table 2 summarizes genome sequencing projects of acidophilic microbes involved in oxidation/reduction of iron and/or RISCs, many of which were isolated from bioleaching operations... The long‐awaited, complete annotated genome sequence of the mesoacidophilic A. ferrooxidans ATCC 23270 (3.0 Mb, 58.8% GC) has only recently been published... As expected, the organism was found to have a complete repertoire of genes required for a free‐living, chemolithoautotrophic lifestyle, including CO2 fixation, nucleotide and cofactor biosynthesis... In the complete genome sequence of the extremely thermoacidophilic archaeon Metallosphaera sedula (2.2 Mb, 46% GC), genes were identified for iron and sulfur oxidation, autotrophic carbon fixation, metal tolerance and adhesion... Comparative genomics with A. ferriooxidans showed that M. sedula has different respiratory electron transport chain components, as it does not appear to contain cytochromes... A classical metagenome sequencing study of a low‐complexity, acid‐mine drainage microbial biofilm, growing within a pyrite ore body, allowed the reconstruction of near‐complete genomes of the iron oxidizers Leptospirillum group II and Ferroplasma type II... Surprisingly, Acidithiobacilli have a very large number of Fe(III)‐siderphore uptake systems, but they do not make siderophores – so in conditions of higher pH 4–5, which may occur in industrial bioleaching heaps, they may scavenge the siderophores of other organisms.

Show MeSH