Exposure of minerals to rainwater, temperature changes and oxidative conditions results in weathering. All these events have driven the formation of sediments, soils and landscapes, determining soil fertility and water quality. Plants and microbes are also involved in formation and destruction of minerals. For example, microorganisms contribute to precipitation of new minerals and to carbonate production. Whereas carbonate precipitation strongly impacts global carbon cycling – mineral weathering – plays a fundamental role in the environment by influencing the bioavailability of chemical elements that can be either beneficial or toxic to living organisms. Microbial mineral weathering is a widespread key process, not only because of its ecological significance but also because it affects human health, as well as architectural and artistic patrimony. Moreover, bacterial mineral weathering is used by industries to recover scarce metals from ore, and fungi might be useful for bioremediation of asbestos-rich soils. Another exciting possibility is the future use of efficient mineral-weathering bacteria to replace chemical fertilization; these microbes are able to promote the growth of plants by releasing trapped mineral nutrients. This biofertilization might result in a reduction of both economical cost and environmental impact of crop production.
Soil microbes play an essential role in the environment by contributing to the release of key nutrients from primary minerals that are required not only for their own nutrition but also for that of plants. Although the role of fungi in mineral weathering is beginning to be elucidated, the relative impact of bacteria in this process and the molecular mechanisms involved remain poorly understood. This ppaer discusses the ecological relevance of bacterial weathering, mainly in the soil and especially in acidic forest ecosystems, which strongly depend on mineral weathering for their sustainability; molecular mechanisms and genetic determinants involved in the dissolution of complex minerals under aerobic conditions; the potential applications of genomic resources to the study of bacterial weathering.