ABSTRACT
Biomineralization is a known natural phenomenon associated with a wide range of bacterial species. Bacterial-induced calcium carbonate precipitation by marine isolates was investigated in this study. Three genera of ureolytic bacteria, Sporosarcina sp., Bacillus sp. and Brevundimonas sp. were observed to precipitate calcium carbonate minerals. Of these species, Sporosarcina sp. dominated the cultured isolates. B. lentus CP28 generated higher urease activity and facilitated more efficient precipitation of calcium carbonate at 3.24 ± 0.25 × 10−4 mg/cell. X-ray diffraction indicated that the dominant calcium carbonate phase was calcite. Scanning electron microscopy showed that morphologies of the minerals were dominated by cubic, rhombic and polygonal plate-like crystals. The dynamic process of microbial calcium carbonate precipitation revealed that B. lentus CP28 precipitated calcite crystals through the enzymatic hydrolysis of urea, and that when ammonium ion concentrations reached 746 mM and the pH reached 9.6, that favored calcite precipitation at a higher level of 96 mg/L. The results of this research provide evidence that a variety of marine bacteria can induce calcium carbonate precipitation, and may influence the marine carbonate cycle in natural environments.
Subject(s)
Bacillus/isolation & purification , Calcium Carbonate/metabolism , Caulobacteraceae/isolation & purification , Geologic Sediments/microbiology , Sporosarcina/isolation & purification , Ammonium Compounds/metabolism , Bacillus/classification , Bacillus/genetics , Bacillus/metabolism , Cluster Analysis , Caulobacteraceae/classification , Caulobacteraceae/genetics , Caulobacteraceae/metabolism , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Hydrogen-Ion Concentration , Microscopy, Electron, Scanning , Molecular Sequence Data , Phylogeny , /genetics , Sequence Analysis, DNA , Sporosarcina/classification , Sporosarcina/genetics , Sporosarcina/metabolism , Urea/metabolism , X-Ray DiffractionABSTRACT
Brevundimonas vesicularis has rarely been isolated from clinical specimens. We report here a case of B. vesicularis bacteremia in a female infant who presented with fever, vomiting and altered sensorium. USG abdomen showed mild hepatomegaly, moderate ascitis with bilateral mild basal pleural effusion. Blood culture was processed by BACTEC BD. Isolate was identified as B. vesicularis, by API ID 32 GN automated system. We have come across only one report of neonatal sepsis caused by B. vesicularis from India. To the best of our knowledge, this is one of the rare case reports of B. vesicularis bacteremia in a female infant.