Taking nature into lab: biomineralization by heavy metal-resistant streptomycetes in soil

[摘要] Biomineralization by heavy metal-resistant streptomycetes was tested toevaluate the potential influence on metal mobilities in soil. Thus, wedesigned an experiment adopting conditions from classical laboratory methodsto natural conditions prevailing in metal-rich soils with media spiked withheavy metals, soil agar, and nutrient-enriched or unamended soil incubatedwith the bacteria. As a result, all strains were able to form struviteminerals (MgNH₄PO₄• 6H₂O) on tryptic soy broth(TSB)-media supplemented with AlCl₃, MnCl₂ and CuSO₄, as wellas on soil agar. Some strains additionally formed struvite onnutrient-enriched contaminated and control soil, as well as on metalcontaminated soil without addition of media components. In contrast,switzerite (Mn₃(PO₄)₂• 7H₂O) was exclusivelyformed on minimal media spiked with MnCl₂ by four heavy metal-resistantstrains, and on nutrient-enriched control soil by one strain. Hydrated nickelhydrogen phosphate was only crystallized on complex media supplemented withNiSO₄ by most strains. Thus, mineralization is a dominant property ofstreptomycetes, with different processes likely to occur under laboratoryconditions and sub-natural to natural conditions. This new understandingmight have implications for our understanding of biological metal resistancemechanisms. We assume that biogeochemical cycles, nutrient storage and metalresistance might be affected by formation and re-solubilization of mineralslike struvite in soil at microscale.

[学科分类] 地球化学与岩石