title: Carbonate Mineral Formation under the Influence of Limestone-Colonizing Actinobacteria: Morphology and Polymorphism.
abstract: Microorganisms and their biomineralization processes are widespread in almost every environment on earth. In this work, Streptomyces luteogriseus DHS C014, a dominant lithophilous actinobacteria isolated from microbial mats on limestone rocks, was used to investigate its potential biomineralization to allow a better understanding of bacterial contributions to carbonate mineralization in nature. The ammonium carbonate free-drift method was used with mycelium pellets, culture supernatant, and spent culture of the strain. Mineralogical analyses showed that hexagonal prism calcite was only observed in the sub-surfaces of the mycelium pellets, which is a novel morphology mediated by microbes. Hemispheroidal vaterite appeared in the presence of spent culture, mainly because of the effects of soluble microbial products (SMP) during mineralization. When using the culture supernatant, doughnut-like vaterite was favored by actinobacterial mycelia, which has not yet been captured in previous studies. Our analyses suggested that the effects of mycelium pellets as a molecular template almost gained an advantage over SMP both in crystal nucleation and growth, having nothing to do with biological activity. It is thereby convinced that lithophilous actinobacteria, S. luteogriseus DHS C014, owing to its advantageous genetic metabolism and filamentous structure, showed good biomineralization abilities, maybe it would have geoactive potential for biogenic carbonate in local microenvironments.
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of SciencesGuiyang, China; Institute of Geochemistry, University of Chinese Academy of SciencesBeijing, China; The Key Laboratory of Biotechnology for Medicinal Plant of Jiangsu Province, School of Life Science, Jiangsu Normal UniversityXuzhou, China.
authors.forename: Chengliang
authors.initials: C
authors.lastname: Cao
authors.affiliation: The Key Laboratory of Biotechnology for Medicinal Plant of Jiangsu Province, School of Life Science, Jiangsu Normal University Xuzhou, China.
authors.forename: Jihong
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Division of Earth and Ecosystem Sciences, Desert Research Institute Las Vegas, NV, USA.
authors.forename: Henry
authors.initials: H
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences Beijing, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences Guiyang, China.
authors.forename: Faxiang
authors.initials: F
authors.lastname: Tao
authors.affiliation: Department of Biotechnology, College of Life Science, Nanjing Normal University Nanjing, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Lian
keywords: Streptomyces luteogriseus DHS C014; biomineralization; doughnut-like vaterite; hexagonal prism calcite; lithophilous actinobacteria