A mineralogical characterization of biogenic calcium carbonates precipitated by heterotrophic bacteria isolated from cryophilic polar regions

Abstract

Precipitation of calcium carbonate (CaCO3(s) ) can be driven by microbial activity. Here, a systematic approach is used to identify the morphological and mineralogical characteristics of CaCO3(s) precipitated during the heterotrophic growth of micro-organisms isolated from polar environments. Focus was placed on establishing mineralogical features that are common in bioliths formed during heterotrophic activity, while in parallel identifying features that are specific to bioliths precipitated by certain microbial phylotypes. Twenty microbial isolates that precipitated macroscopic CaCO3(s) when grown on B4 media supplemented with calcium acetate or calcium citrate were identified. A multimethod approach, including scanning electron microscopy, high-resolution transmission electron microscopy, and micro-X-ray diffraction (μ-XRD), was used to characterize CaCO3(s) precipitates. Scanning and transmission electron microscopy showed that complete CaCO3(s) crystal encrustation of Arthrobacter sp. cells was common, while encrustation of Rhodococcus sp. cells did not occur. Several euhedral and anhedral mineral formations including disphenoid-like epitaxial plates, rhomboid-like aggregates with epitaxial rhombs, and spherulite aggregates were observed. While phylotype could not be linked to specific mineral formations, isolates tended to precipitate either euhedral or anhedral minerals, but not both. Three anhydrous CaCO3(s) polymorphs (calcite, aragonite, and vaterite) were identified by μ-XRD, and calcite and aragonite were also identified based on TEM lattice-fringe d value measurements. The presence of certain polymorphs was not indicative of biogenic origin, although several mineralogical features such as crystal-encrusted bacterial cells, or casts of bacterial cells embedded in mesocrystals are an indication of biogenic origin. In addition, some features such as the formation of vaterite and bacterial entombment appear to be linked to certain phylotypes. Identifying phylotypes consistent with certain mineralogical features is the first step toward discovering a link between these crystal features and the precise underlying molecular biology of the organism precipitating them.

Biological Characterization of Microenvironments in a Hypersaline Cold Spring Mars Analog

“…The dominant rod-shaped cells are consistent with the morphology of Marinobacter and Psychroflexus. The rough surface texture apparent on the cells imaging in RM is suggestive of mineral precipitation ( Ronholm et al, 2014 ). Cell-coating secondary mineral precipitation can occur through either passive or active biomineralization processes.…”

Microbial Diversity and Mineralogical-Mechanical Properties of Calcitic Cave Speleothems in Natural and in Vitro Biomineralization Conditions

“…These structures are known by different names as stalactites, stalagmites, moonmilk, drip stones, and flowstones depending upon their location (from floors, walls to ceilings) and appearance (soft, spongy, fibrous, or stony) ( Borsato et al, 2000 ; Jones, 2001 ; Melim et al, 2008 ). The inorganic and physical chemistry that drive these phenomena is well established ( Banks et al, 2010 ; Pacton et al, 2013 ), however, a growing body of research indicates that microorganisms can play an important role in carbonate precipitation during speleothem growth ( Banks et al, 2010 ; Rusznyak et al, 2012 ; Ronholm et al, 2014 ). Several studies on the analysis of the mineralogy and geochemistry of different cave environments have been conducted ( White, 1962 ; Harmon et al, 1983 ; Hill and Forti, 1986 ; Leél-Őssy et al, 2011 ).…”

Bacterial Community Dynamics and Biocement Formation during Stimulation and Augmentation: Implications for Soil Consolidation

“…Calcium carbonates exist in different polymorphs with varying morphologies and characteristics as calcite (rhombic), aragonite (needle like), vaterite (spherical), two hydrated crystalline phases monohydrocalcite, ikaite and amorphous phases (Rodriguez-Navarro et al, 2012; Ronholm et al, 2014; Bains et al, 2015; Anbu et al, 2016). The formation of these polymorphs has been reported to be influenced by a number of parameters including bacterial species involved and metabolic pathway associated as they control the amount of dissolved organic carbon, which is the major player in polymorph selection (Rodriguez-Navarro et al, 2012; Dhami et al, 2013b).…”