Environmental Engineering Reference
In-Depth Information
Table 2.1 Physiological groups of chemotrophic prokaryotes
Evolutionary lines of
prokaryotes
Physiological groups
Fermenting
prokaryotes
Anoxic
respiring
prokaryotes
Microaerophilic
and facultative
anaerobic
prokaryotes
Aerobic
respiring
prokaryotes
Gram-negative Bacteria
(prokaryotes of aquatic
evolutionary origin)
1
2
3
4
Gram-positive Bacteria
(prokaryotes of terrestrial
evolutionary origin)
5
6
7
8
Archaea (prokaryotes of
extreme environments
evolutionary origin)
9
10
11
12
of terrestrial evolutionary origin with thick and rigid cell wall), Gram-negative
Bacteria (prokaryotes of aquatic evolutionary origin with thin and elastic cell wall)
and Archaea (prokaryotes of environments with extreme temperature, pH, or
strong anaerobic conditions). These three evolutionary lines contain four parallel
physiological groups differentiated by the type of energy-yielding oxidation-
reduction reactions: (1) fermenting, (2) anoxic respiring, (3) microaerophilic and
facultative anaerobic, and (4) aerobic respiring prokaryotes. In total, there are 12
groups of chemotrophic prokaryotes differentiated by the type of energy-yielding
oxidation-reduction reactions (Table
2.1
).
Depending on the real conditions and requirements of the construction process,
all these physiological groups can be involved in biotechnologies of construction
materials or construction process biotechnologies. However, in majority cases
anaerobic, anoxic, facultative anaerobic, and aerobic Gram-positive bacteria are
most suitable for applications related to the soil improvement because of osmotic
tolerance of these bacteria. Facultative anaerobic or aerobic Gram-negative bac-
teria are most suitable for biosynthesis of construction biomaterials. Applications
of phototrophic (utilizing light energy) prokaryotes in civil engineering are rare.
For example, Gram-negative phototrophic Bacteria, cyanobacteria can be used for
the formation of soil crust to diminish water and wind erosion of soil.
The microorganisms that are used to start up the bioprocess are called inoculum
by microbiologists or ''seeds'' by civil and environmental engineers. The inoculum
could be a suspended, frozen, dried, or cooled microbial biomass. Cultivation after
inoculation is performed in batch or continuous mode. Inoculum for construction
materials production or biotreatment of soil/particles is selected using the fol-
lowing microbiological and molecular-biological methods:
(1)
Obtaining and testing of the microbial strains from national collections of
microorganisms, for example American Type Culture Collection (ATCC,
USA) or German Collection of Microorganisms and Cell Cultures (DSMZ,
Germany).
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