Bioleaching microbes — organisms that solubilize metals and can accumulate silver Which microorganism group is classically used to leach metals from sulfide ores and is well known in biohydrometallurgy (including processes that can lead to silver accumulation)?

Introduction / Context:
Bioleaching harnesses chemolithoautotrophic bacteria to oxidize sulfide minerals, releasing metals into solution. These processes operate at scale for copper, gold, and other metals, and can lead to mobilization and recovery of precious metals such as silver.

Given Data / Assumptions:

• Thiobacillus (now reclassified largely as Acidithiobacillus) oxidizes ferrous iron and reduced sulfur compounds.
• Their metabolism generates ferric iron and sulfuric acid, which attack metal sulfides.
• Other listed microbes are not the classical bioleaching workhorses.

Concept / Approach:

Acidithiobacillus ferrooxidans and related species catalyze oxidative dissolution of ores such as chalcopyrite and argentiferous minerals. The resulting metal-rich liquors can be processed to recover copper, gold, silver, and other metals.

Step-by-Step Solution:

Verification / Alternative check:

Industrial heap/dump bioleaching operations cite Acidithiobacillus spp. as primary catalysts, corroborating their central role in metal solubilization and recovery.

Why Other Options Are Wrong:

Pseudomonads are versatile bioremediators but not primary ore-leaching bacteria. Zoogloea ramigera is associated with activated sludge flocs. Yeast is not used for sulfide ore bioleaching.

Common Pitfalls:

Conflating general bioremediation microbes with acidophilic lithotrophs specialized for ore oxidation.

Final Answer:

Thiobacillus (e.g., Acidithiobacillus spp.)