Bacillus, Arthrobacter, Agrobacterium, Pseudomonas, Flavobacterium, and
Alcaligenes.
Bacterial activity in the soil determines the fertility, soil properties, and evolution,
interfering with ammo-nitrification processes, decomposing resistant nitrate
compounds (e.g., chitin), forming HSs, and balancing the microbiota of this medium
by secretion of antibiotics. In the soil substrate, there are groups of specialized
bacteria that develop on specific substrates: cellulosic bacteria degrade cellulose
from the remaining vegetal matter left in the soil, and nitrifying bacteria produce
NH 3 oxidation resulting from metabolism processes, with the formation of nitrate
(NO 3
À ) and nitrite (NO 2
À ), form by which plants take nitrogen from the soil.
Sulfurous ferruginous bacteria play a role in the S and Fe circuit in nature and
putrefaction bacteria-degrade organic N and cause rotting corpses. Actinomycetes
(filamentous bacteria) represent approx. 30% of the total soil microflora. Together
with bacteria, they determine the mineralization of OSs and take part in the formation of humus, which is the reservoir of nutrients for plants. Soil closure is due to
actinomycetes. This type of soil retains better heat and has superior agrotechnical
qualities. They occur in all soil types and are more numerous in soils rich in OSs. It
develops mainly in alkaline soils. They are the main ammonium and chitinolysis
agents, having a role in the formation of humus. Some species, producing antibiotics,
also play a role in maintaining balance in the soil microflora. Excessive humidity and
acidity limit their development (Okie et al. 2015).
The most common genera are Actinomyces, Actinoplanes, Mycobacterium,
Mycococus, Micromonospora, Nocardia, and Streptomyces. Pathogenic sporulated
bacteria can be found in the soil: Bacillus anthracis (produce the anthrax of the
sheep), Clostridium tetani (produces tetanus), Clostridium botulinum, Clostridium
hystoliticum, and Clostridium sporogenes (toxicogenic bacteria). They accidentally
land in the soil by manure or dead bodies: Salmonella typhi, Shigella dysenteriae,
Vibrio cholerae, and Pseudomonas aeruginosa. The durability of these bacteria in
the soil varies according to species, soil type, and climatic conditions. Pathogenic
bacteria do not find favorable multiplication conditions in the soil due to the low
temperature relative to their thermal optimum (37
C) and inappropriate nutritional
environment and due to the competition of other bacteria, actinomycetes, and
protozoan predator (Acanthamoeba castellanii). Cyanobacteria form a large group
of photosynthetic MOs from the superficial soil layers. Dominant are the Nostoc and
Oscillatoria genera. They are important because they are the only living organisms
capable of using both carbon in CO 2 and molecular nitrogen in the synthesis of OSs.
The molecular nitrogen fixative species are Anabaena, Calothrix, Chroococcus,
Nostoc, Plectonema, and Schizothrix (Maier et al. 2018).
The viruses are especially present in the form of bacteriophages and
actinophages, living in a dynamic balance with the bacterial and actinomycete
species they parasite, having a weak lytic action on them. Pathogenic viruses cannot
be propagated through the soil. Yeasts and microfungi (molds) are represented in the
superficial soil layers that are better aerated, wet, and rich in OSs. The most common
genera are Candida, Cryptococcus, Debaryomyces, Hansenula, Lipomyces, and
4 Advanced Technologies for Ecological Reconstruction and Bioremediation of. . .
85
Alcaligenes.
Bacterial activity in the soil determines the fertility, soil properties, and evolution,
interfering with ammo-nitrification processes, decomposing resistant nitrate
compounds (e.g., chitin), forming HSs, and balancing the microbiota of this medium
by secretion of antibiotics. In the soil substrate, there are groups of specialized
bacteria that develop on specific substrates: cellulosic bacteria degrade cellulose
from the remaining vegetal matter left in the soil, and nitrifying bacteria produce
NH 3 oxidation resulting from metabolism processes, with the formation of nitrate
(NO 3
À ) and nitrite (NO 2
À ), form by which plants take nitrogen from the soil.
Sulfurous ferruginous bacteria play a role in the S and Fe circuit in nature and
putrefaction bacteria-degrade organic N and cause rotting corpses. Actinomycetes
(filamentous bacteria) represent approx. 30% of the total soil microflora. Together
with bacteria, they determine the mineralization of OSs and take part in the formation of humus, which is the reservoir of nutrients for plants. Soil closure is due to
actinomycetes. This type of soil retains better heat and has superior agrotechnical
qualities. They occur in all soil types and are more numerous in soils rich in OSs. It
develops mainly in alkaline soils. They are the main ammonium and chitinolysis
agents, having a role in the formation of humus. Some species, producing antibiotics,
also play a role in maintaining balance in the soil microflora. Excessive humidity and
acidity limit their development (Okie et al. 2015).
The most common genera are Actinomyces, Actinoplanes, Mycobacterium,
Mycococus, Micromonospora, Nocardia, and Streptomyces. Pathogenic sporulated
bacteria can be found in the soil: Bacillus anthracis (produce the anthrax of the
sheep), Clostridium tetani (produces tetanus), Clostridium botulinum, Clostridium
hystoliticum, and Clostridium sporogenes (toxicogenic bacteria). They accidentally
land in the soil by manure or dead bodies: Salmonella typhi, Shigella dysenteriae,
Vibrio cholerae, and Pseudomonas aeruginosa. The durability of these bacteria in
the soil varies according to species, soil type, and climatic conditions. Pathogenic
bacteria do not find favorable multiplication conditions in the soil due to the low
temperature relative to their thermal optimum (37
C) and inappropriate nutritional
environment and due to the competition of other bacteria, actinomycetes, and
protozoan predator (Acanthamoeba castellanii). Cyanobacteria form a large group
of photosynthetic MOs from the superficial soil layers. Dominant are the Nostoc and
Oscillatoria genera. They are important because they are the only living organisms
capable of using both carbon in CO 2 and molecular nitrogen in the synthesis of OSs.
The molecular nitrogen fixative species are Anabaena, Calothrix, Chroococcus,
Nostoc, Plectonema, and Schizothrix (Maier et al. 2018).
The viruses are especially present in the form of bacteriophages and
actinophages, living in a dynamic balance with the bacterial and actinomycete
species they parasite, having a weak lytic action on them. Pathogenic viruses cannot
be propagated through the soil. Yeasts and microfungi (molds) are represented in the
superficial soil layers that are better aerated, wet, and rich in OSs. The most common
genera are Candida, Cryptococcus, Debaryomyces, Hansenula, Lipomyces, and
4 Advanced Technologies for Ecological Reconstruction and Bioremediation of. . .
85