Biomineralization results directly from microbial metabolic processes creating the conditions for inorganic minerals to deposit within and around cells. Across diverse habitats, many cyanobacterial species, biofilms or planktonic, promote extracellular calcium carbonate (CaCO₃) precipitation or intracellular CaCO₃ deposits. Although biomineralization occurs across all domains of life, cyanobacteria display an exceptional capacity for this process. Cyanobacterial mineralization is largely a byproduct of photosynthetisis, supported by carbonic anhydrases (CAs), the carbon-concentrating mechanism (CCM), and the production of extracellular polymeric substances (EPS). Environmental factors including pH, ion concentration, nutrient levels, temperature, salinity, and hydrodynamic conditions influence the occurrence and rate of mineral precipitation and its composition and morphology. Through these mineralizing activities, cyanobacteria modify sediment properties, contribute to global carbon cycling, and generate extensive geological formations. Simultaneously, the formation of mineralized structures, often associated with organic matrices, enhances cyanobacterial survival by providing mechanical protection, improving metabolic efficiency, and increasing ecological competitiveness. In this review, we present an integrated perspective on the biological, metabolic, molecular, and environmental foundations of cyanobacterial biomineralization. Highlighting the mechanisms connecting EPS synthesis, biofilm dynamics and photosynthesis to mineral formation in natural and artificial environments. Compared with other microbial systems, cyanobacterial biomineralization offers a sustainable safe option for promising applications, particularly bioconsolidation for cultural heritage conservation. Their controllable growth, adaptability to diverse substrates and challenging environments, and ability to form cohesive mineral–organic matrices make them especially suitable for novel and impactful applications such as the bioconsolidation of weathered stone heritage and the production of geomaterial under microgravity. • Cyanobacteria are among the most significant microbial taxa contributing to biomineralization and carbon sequestration. • Cyanobacterial biomineralization is not solely extracellular and a byproduct of photosynthesis, but also a controlled intracellular process. • Biomineralization of CaCO 3 by cyanobacterial emerges as a promising and innovative strategy for bioconsolidation and the conservation of stone heritage. • Cyanobacteria thrive in diverse and extreme habitats by modulating metabolic capacities like photosynthesis and biomineralization in response to environmental signals. • The factors that facilitate cyanobacterial biomineralization considering established concepts and new discoveries are discussed in detail.
Corredor et al. (Fri,) studied this question.