bacteria are those microbes which consume chemicals from the rock as an energy
source and create their own food (Atomi 2002). Chemolithotrophic microorganism
occurs in dark habitats like hydrothermal vents, areas of the deep terrestrial subsurface, like caves and area where low organic carbon is present and no competition
with photosynthetic organisms occurs. In nutrient deficient habitats, the bacteria fix
CO 2 into organic compound through the oxidation of inorganic compounds such as
iron, sulfur, and manganese, and supply the energy to higher trophic levels (Madigan
et al. 2003).
11.3 Microbial Precipitation of Calcium Carbonate
Most of the bacterial species are capable to precipitate carbonates in an alkaline
environment rich in Ca
2+ ions. Carbonate precipitation by bacteria is a complex
process which was described by (Castanier et al. 2000). Carbonate precipitation is
associated with metabolic pathways like photosynthesis, nitrogen, and sulfur cycles,
and ion exchange (Ca
2+ /H
+
). Some researcher found that carbonate metabolism also
identified six genes which involved in crystal formation in Bacillus subtilis PB19
(Barabesi et al. 2007). The calcium carbonate precipitation by bacteria has been
described for involvement in positively charged Ca2+ ions and negatively charged
bacteria Cell walls (Hammes and Verstraete 2002). These Ca
2+ ion-cell wall
interactions produce changes in the overall charge of the cell wall. This process
permitting interaction between differently charged bacteria. Due to changes in the
overall ionic charge, bacteria aggregate to increase the size of the biomineral, and in
turn, bacteria become the nucleus of the biomineral (Ferrer et al. 1988; Rivadeneyra
et al. 1996, 1998). Figure 11.1 described the typical environment of calcium
carbonate precipitation which contain high extracellular calcium concentrations
(compared to intracellular) and low extracellular related to intracellular proton
concentrations (as a result of alkaline condition). The combination of an extracellular
alkaline pH and calcium ions poses an expectedtense environment for bacteria:
passive calcium influx as a result of the complementary Ca
2+ /2H
+ electrochemical
gradients will lead to intracellular calcium intake and excessive proton expulsion
(Dania et al. 2009) (Fig. 11.1a).
Survival under such conditions requires active export of intracellular calcium.
The ATP dependent calcium pumps, which would decrease intracellular calcium
ions and at the same time compensate the proton loss (Fig. 11.1, second b). The latter
event could result in a localized increase in pH, due to proton uptake, in the same
region as the calcium ion increase, which would procedure an ideal localized
precipitation micro environment (Fig. 11.1, section c). The formation of localized
micro-environments, survival of the organism is dependent on active calcium
metabolism. The energy (ATP) is required for the metabolism of organic substance
and produce CO 2 as a by-product which is used as a carbonate. The bacteria will lead
to increase in the extracellular dissolve inorganic carbon for the survival and
proliferation which would affect the solubility of CaCO 3 , which also service the
precipitation on calcium carbonate (Hammes and Verstraete 2002; Dania et al.
2009).
11 Sequestration of Carbon Dioxide by Microorganism and Production of Value. . .
237
source and create their own food (Atomi 2002). Chemolithotrophic microorganism
occurs in dark habitats like hydrothermal vents, areas of the deep terrestrial subsurface, like caves and area where low organic carbon is present and no competition
with photosynthetic organisms occurs. In nutrient deficient habitats, the bacteria fix
CO 2 into organic compound through the oxidation of inorganic compounds such as
iron, sulfur, and manganese, and supply the energy to higher trophic levels (Madigan
et al. 2003).
11.3 Microbial Precipitation of Calcium Carbonate
Most of the bacterial species are capable to precipitate carbonates in an alkaline
environment rich in Ca
2+ ions. Carbonate precipitation by bacteria is a complex
process which was described by (Castanier et al. 2000). Carbonate precipitation is
associated with metabolic pathways like photosynthesis, nitrogen, and sulfur cycles,
and ion exchange (Ca
2+ /H
+
). Some researcher found that carbonate metabolism also
identified six genes which involved in crystal formation in Bacillus subtilis PB19
(Barabesi et al. 2007). The calcium carbonate precipitation by bacteria has been
described for involvement in positively charged Ca2+ ions and negatively charged
bacteria Cell walls (Hammes and Verstraete 2002). These Ca
2+ ion-cell wall
interactions produce changes in the overall charge of the cell wall. This process
permitting interaction between differently charged bacteria. Due to changes in the
overall ionic charge, bacteria aggregate to increase the size of the biomineral, and in
turn, bacteria become the nucleus of the biomineral (Ferrer et al. 1988; Rivadeneyra
et al. 1996, 1998). Figure 11.1 described the typical environment of calcium
carbonate precipitation which contain high extracellular calcium concentrations
(compared to intracellular) and low extracellular related to intracellular proton
concentrations (as a result of alkaline condition). The combination of an extracellular
alkaline pH and calcium ions poses an expectedtense environment for bacteria:
passive calcium influx as a result of the complementary Ca
2+ /2H
+ electrochemical
gradients will lead to intracellular calcium intake and excessive proton expulsion
(Dania et al. 2009) (Fig. 11.1a).
Survival under such conditions requires active export of intracellular calcium.
The ATP dependent calcium pumps, which would decrease intracellular calcium
ions and at the same time compensate the proton loss (Fig. 11.1, second b). The latter
event could result in a localized increase in pH, due to proton uptake, in the same
region as the calcium ion increase, which would procedure an ideal localized
precipitation micro environment (Fig. 11.1, section c). The formation of localized
micro-environments, survival of the organism is dependent on active calcium
metabolism. The energy (ATP) is required for the metabolism of organic substance
and produce CO 2 as a by-product which is used as a carbonate. The bacteria will lead
to increase in the extracellular dissolve inorganic carbon for the survival and
proliferation which would affect the solubility of CaCO 3 , which also service the
precipitation on calcium carbonate (Hammes and Verstraete 2002; Dania et al.
2009).
11 Sequestration of Carbon Dioxide by Microorganism and Production of Value. . .
237