molecular aspects, and discusses the significance of the precipitation event also
from an evolutionary point of view.
Microbiogeochemistry? The proof of the microbiogeochemical process is undeniable, but
we have yet to ascertain its magnitude and importance. Is it conceivable that life forms so
small could be indispensable for something so enormous? (Beveridge 1989)
5.1 Introduction
Calcium carbonate precipitation (CCP) is a widespread process among bacteria,
not restricted to any taxonomic group (Boquet et al. 1973) and common in
different environments such as marine waters and sediments, freshwater, and
soils (Castanier et al. 1999; Ehrlich 1998). It has drawn much attention in recent
decades because of its relevant implications in natural processes and its potentiality in numerous applications. It represents a fundamental part of the calcium
biogeochemical cycle as well as the carbon one (Zavarzin 2002), contributing to
atmospheric CO 2 fixation and to a vast reservoir of carbon sequestering through
formation of calcium carbonate (CC) sediments, deposits, and rocks. Bacterial
calcium carbonate precipitation (BCCP) is also involved in the production of
pathological concretions such as gallstones and kidney stones in humans and
recently the presence of microbial signatures preserved in the rock record has
been investigated to assess biogenic origin for speleothems and other carbonates
(Barton et al. 2001).
Proposed innovative applications of CaCO 3 mineralization by bacteria
include biomimetic processes and materials and examples of bioremediation
(and stabilization) in several fields ranging from applied environmental microbiology (leaching, solid-phase capture of inorganic contaminants), to civil and
environmental engineering (sediment dikes, bioplugging, biogrouting, and selfhealing of concrete and limestone structures) and conservation of monumental
calcareous stones. For implications and applications of BCCP, see references in
Rodriguez-Navarro et al. (2003); Barabesi et al. (2007); De Muynck et al.
(2010).
Different mechanisms of bacterial involvement in calcification have been proposed (Ehrlich 1996) and they have been a matter of controversy throughout the last
century (von Knorre and Krumbein 2000). The studies made in this field have
pointed out the complexity of the phenomenon that can be influenced by the
environmental physicochemical conditions and it is correlated both to the metabolic
activity and the cell surface structures of microorganisms (Castanier et al. 1999;
Beveridge 1989; Fortin et al. 1997).
Although BCCP is a widely occurring natural process and has been investigated
extensively both in natural environments and under defined laboratory conditions,
the role played by bacteria in calcium mineralization is still debated (von Knorre
and Krumbein 2000; Zavarzin 2002). CC deposition by bacteria is a process
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B. Perito and G. Mastromei
from an evolutionary point of view.
Microbiogeochemistry? The proof of the microbiogeochemical process is undeniable, but
we have yet to ascertain its magnitude and importance. Is it conceivable that life forms so
small could be indispensable for something so enormous? (Beveridge 1989)
5.1 Introduction
Calcium carbonate precipitation (CCP) is a widespread process among bacteria,
not restricted to any taxonomic group (Boquet et al. 1973) and common in
different environments such as marine waters and sediments, freshwater, and
soils (Castanier et al. 1999; Ehrlich 1998). It has drawn much attention in recent
decades because of its relevant implications in natural processes and its potentiality in numerous applications. It represents a fundamental part of the calcium
biogeochemical cycle as well as the carbon one (Zavarzin 2002), contributing to
atmospheric CO 2 fixation and to a vast reservoir of carbon sequestering through
formation of calcium carbonate (CC) sediments, deposits, and rocks. Bacterial
calcium carbonate precipitation (BCCP) is also involved in the production of
pathological concretions such as gallstones and kidney stones in humans and
recently the presence of microbial signatures preserved in the rock record has
been investigated to assess biogenic origin for speleothems and other carbonates
(Barton et al. 2001).
Proposed innovative applications of CaCO 3 mineralization by bacteria
include biomimetic processes and materials and examples of bioremediation
(and stabilization) in several fields ranging from applied environmental microbiology (leaching, solid-phase capture of inorganic contaminants), to civil and
environmental engineering (sediment dikes, bioplugging, biogrouting, and selfhealing of concrete and limestone structures) and conservation of monumental
calcareous stones. For implications and applications of BCCP, see references in
Rodriguez-Navarro et al. (2003); Barabesi et al. (2007); De Muynck et al.
(2010).
Different mechanisms of bacterial involvement in calcification have been proposed (Ehrlich 1996) and they have been a matter of controversy throughout the last
century (von Knorre and Krumbein 2000). The studies made in this field have
pointed out the complexity of the phenomenon that can be influenced by the
environmental physicochemical conditions and it is correlated both to the metabolic
activity and the cell surface structures of microorganisms (Castanier et al. 1999;
Beveridge 1989; Fortin et al. 1997).
Although BCCP is a widely occurring natural process and has been investigated
extensively both in natural environments and under defined laboratory conditions,
the role played by bacteria in calcium mineralization is still debated (von Knorre
and Krumbein 2000; Zavarzin 2002). CC deposition by bacteria is a process
114
B. Perito and G. Mastromei