Bacteria-induced mineral precipitation: a mechanistic review.

Micro-organisms contribute to Earth's mineral deposits through a process known as bacteria-induced mineral precipitation (BIMP). It is a complex phenomenon that can occur as a result of a variety of physiological activities that influence the supersaturation state and nucleation catalysis of mineral precipitation in the environment. There is a good understanding of BIMP induced by bacterial metabolism through the control of metal redox states and enzyme-mediated reactions such as ureolysis. However, other forms of BIMP often cannot be attributed to a single pathway but rather appear to be a passive result of bacterial activity, where minerals form as a result of metabolic by-products and surface interactions within the surrounding environment. BIMP from such processes has formed the basis of many new innovative biotechnologies, such as soil consolidation, heavy metal remediation, restoration of historic buildings and even self-healing concrete. However, these applications to date have primarily incorporated BIMP-capable bacteria sampled from the environment, while detailed investigations of the underpinning mechanisms have been lagging behind. This review covers our current mechanistic understanding of bacterial activities that indirectly influence BIMP and highlights the complexity and connectivity between the different cellular and metabolic processes involved. Ultimately, detailed insights will facilitate the rational design of application-specific BIMP technologies and deepen our understanding of how bacteria are shaping our world.