Open AccessCharacterization of the CaCO3 biomineral in coralline red algae (Corallinales) from the Pacific coast of Mexico
Author(s) -
Dalila Fragoso,
F Ramírez-Cahero,
Andrés RodríguezGalván,
R Hernández-Reyes,
Alejandro Heredia,
Dení Rodríguez,
Manuel Aguilar-Franco,
L. Bucio,
Vladimir A. Basiuk
Publication year - 2010
Publication title -
ciencias marinas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.215
H-Index - 29
eISSN - 2395-9053
pISSN - 0185-3880
DOI - 10.7773/cm.v36i1.1606
Subject(s) - aragonite , calcite , coralline algae , biomineralization , fourier transform infrared spectroscopy , vaterite , algae , mineral , chemistry , mineralogy , infrared spectroscopy , mineralization (soil science) , materials science , crystallography , chemical engineering , geology , botany , biology , organic chemistry , paleontology , engineering , nitrogen
Coralline red algae assimilate HCO3– to precipitate CaCO3 in their tissues in the form of calcite or aragonite. A characterization of the biomolecular content and the crystalline structure of the biomineral of coralline red algae from the Pacific coast of Mexico was performed by powder X-ray diffraction (XRD), scanning electron (SEM) and tunneling microscopy (STM), and Fourier transform infrared spectroscopy (FTIR). The preliminary conclusion drawn from the results is that this type of calcite-aragonite biomineral has a very low organic content occluded within the crystals. FTIR bands at 2945 and 2889 cm–1 indicate that the most likely organic molecules are carbohydrates; moreover, peptide bond bands (amide I ~1640 and amide II ~1540 cm–1) were not detected, suggesting that proteins are not related to mineral synthesis or their stabilization. This could be explained if the biomineral is synthesized by a biologically controlled extracellular mineralization process. The XRD study showed two main mineral phases, calcite and aragonite, with very similar structural parameters to the inorganic mineral counterparts. The crystallite shapes, seen by STM, were found as plates and needles with different sizes, between 20 and 100 nm.