PNNL

Abstract

Recently, there has been a focus on using soil microbes as a means to store carbon in the soil in the form of calcium carbonate as a way to reduce atmospheric CO2. The molecular processes, and some of the individual species, involved in microbially induced calcium carbonate formation are known but there is still a significant knowledge gap regarding how community interactions, emergent processes that are distinct from the roles of individual members, may drive the formation of carbonate. To answer these questions, we describe the development and application of a community of soil microbes consisting of one species each of the Rhodococcus, Microbacterium and Curtobacterium genera and two species from the Bacillus genera. We term these five species cultivated together carbon storing community A (CSC-A). Growth assays show that only a subset of CSC-A members produce CaCO3 with Rhodococcus producing the most CaCO3 but that the CSC-A community produces almost twice as much CaCO3 as sum total carbonate produced by all member species. The development of CSC-A shows that CaCO3 production may be as much a community process as it is the contribution of individual species, requiring us to move beyond single species analysis to fully understand carbonate formation by microbial communities in nature. CSC-A will allow the scientific community to ask and answer key questions about the molecular interactions surrounding carbon sequestration in soil, an important knowledge gap that must be filled if we wish to harness soil systems for long term storage of carbon from the atmosphere.