Beyond carbonate biomineralization: Why prokaryote-driven CO₂ sequestration demands holistic evaluation

Richard Schinteie^1*Veena Nagaraj²Linda Stalker³Nai Tran-Dinh¹David Midgley⁴

• ¹CSIRO Energy, Lindfield, Australia
• ²CSIRO Environment, Perth, Australia
• ³CSIRO Energy, Perth, Australia
• ⁴CSIRO Energy, Pullenvale, Australia

Microbially induced carbonate precipitation (MICP) offers a promising biological approach to sequester atmospheric CO₂ as stable mineral carbonates, mitigating climate change impacts. This perspective highlights the complexity underpinning prokaryote-driven biomineralization processes, emphasizing the necessity for holistic evaluation beyond simple carbonate formation. Key metabolic pathways such as carbonic anhydrase-mediated CO₂ hydration, ureolysis, photosynthesis, and sulfate reduction contribute variably to mineral precipitation and local pH modulation. Furthermore, calcium carbonate polymorphs with varying stability form can affect carbon storage durability, while net carbon sequestration estimates often overlook critical factors including respiratory CO₂ release, growth phases, and embodied emissions in microbial nutrient substrates. Finally, differentiating between transient microbial organic carbon and long-term mineral carbon storage is essential for accurate carbon accounting. Lifecycle carbon footprints vary significantly with metabolic strategies and substrate choices, impacting sustainable application prospects. Advancing MICP as an effective carbon removal technology requires integrated assessment of microbial physiology, environmental interactions, and process lifecycle emissions to optimize CO₂ drawdown with environmental and economic viability.