Precipatation of calcium carbonate by Vibrio spp. from an inland saltern

Abstract

Calcium carbonate precipitation by 63 strains of moderately halophilic bacteria (Vibrio spp.) isolated from water of a saltern pond has been studied, taking into account the influence of salinity and temperature on the quantity and type of crystals precipitated. The bacteria formed crystals under all the conditions tested. All the crystals were magnesium calcite, with a variable Mg content, depending upon the medium provided. No aragonite was detected, even in a media with high Mg contents. Whether these microorganisms play an active role in precipitation is discussed, as well as the possibility that they may contribute to CaCO 3 precipitation in their natural habitats.

Biomineralization of Carbonates by Marinococcus albus and Marinococcus halophilus Isolated from the Salar de Atacama (Chile)

“…No crystal formation was observed on the control plates. The greatest number of crystalforming strains was in M. halophilus at salt concentrations of 7.5% and 15% (similar in both) and in M. albus at 7.5%; these results differ from those obtained in other moderately halophilic bacteria [5, 6,15,16,18].…”

“…However, M. halophilus and M. albus required a longer time to initiate precipitation, more similar to that required by Bacillus sp. [15] than by the moderately halophilic, Gram-negative bacteria mentioned previously [5, 6,16,18].…”

“…However, this would not account for the increase in the number of strains of both species which formed carbonates at 15% and which in both species was greater than at a salt concentration of 3%. Ferrer et al [5,6] and Rivadeneyra et al [15,16] have shown that the inhibitory effect of magnesium ions is less marked in moderately halophilic bacteria than in nonhalophilic bacteria. Our results confirm these observations, since, in both M. albus and M. halophilus, the influence of the magnesium ions seems to be even less than in other moderately halophilic bacteria.…”

“…2.b), proceeding from the formation and simultaneous growth of bioliths close to each other and which finally coalesced, should be noted. The spherulitic morphologies are also characteristic of the bioliths formed by other moderately halophilic bacteria [5,6,[14][15][16][17][18]. The bioliths were often not very porous superficially (Fig.…”

“…Moderately halophilic bacteria (optimal growth at a salt concentration between 3% and 15% wt/vol) constitute a highly useful group of microorganisms to determine how the ionic composition of the environment affects the precipitation of carbonates by bacteria. We studied the precipitation of carbonates by different, moderately halophilic bacteria [5,6,15,16,18] and found that there are differences between them, especially in terms of the mineralogy of the bioliths formed. In-depth investigation of these differences could help to further our knowledge of the role of bacteria in carbonate formation and their possible involvement in the precipitation of carbonates in natural habitats.…”