Abstract:

Microbial mineral weathering is one of the most active and universal geological processes in the earth surface system. Microorganisms can degrade potassium-bearing rocks (mainly silicate minerals), release elements such as potassium, silicon and calcium, and promote mineral carbonate precipitation under appropriate environmental conditions, functioning as an important link in the geochemical cycles of earth surface elements. Microbial biotransformation of rocks involves growths and metabolic regulations of microorganisms, migration and transformation of elements and evolutionary sequence of secondary minerals-all are important research topics in mineralogy, microbiology and molecular biology. Combining researches in these areas is beneficial for systematically studying the process of microbial weathering of potassium-containing silicate minerals coupled with carbonation and its molecular regulation mechanism. It was confirmed that under the conditions of pure culture experiments, the synergistic effects of acidolysis, chelation, oxidoreduction and other chemical activities are effective in the microbial weathering processes, and the effective weathering can also be achieved by regulating the microbial relevant functional gene expression in response to potassium-deficient environments. Such effects clearly depend on a refined and specific molecular regulation mechanism through long-term evolution of microorganisms. In the soil ecological environment, a significant feature of microbial mineral weathering is the cooperative interaction of microbial communities in the habitats. The participation of microbial carbonic anhydrase in silicate mineral weathering, along with carbonate mineral formation, may be a long-neglected process of earth surface carbon sink. An in-depth exploration of such process will help us further understand the mechanisms of microbial driving carbon migration and transformation in geologic evolutionary history. The utilization of organic fertilizers containing potassium-bearing rock powders has shown positive effects on soil improvement, crop growth and carbon sequestration, which provides a new idea for using the biological weathering of silicate minerals to delay the continuous increase of atmospheric CO₂ concentration. In this paper, we reviewed the molecular mechanisms and carbon sequestration effect of potassium released from biotransformation of potassium-bearing rocks by microorganisms, so as to promote rapid development in this research area.

Key words: potassium rock, silicate minerals, microbial transformation, molecular mechanism, mineral weathering, carbon sink