4.2
Natural Bioresources Involved in Bioremediation
4.2.1 Enzymatic Soil Activity
Enzymatic soil activity is a soil quality parameter and is the result of the activity of
accumulated enzymes and enzymes from proliferating MOs. The sources of the
enzymes accumulated in the soil are MOs cells and organic residues (vegetal and
animal). Enzymes accumulate in the soil as free enzymes (exoenzymes released from
living cells and endoenzymes released from disintegrated cells) and enzymes linked
to cellular constituents, i.e., enzymes present in disintegrating cells (in cellular
fragments) in living but nonproliferating cells.
Enzymes of proliferating MOs are both those that are released from living cells
undergoing multiplication as well as those found within cells undergoing multiplication. Free enzymes are adsorbed by organic and mineral particles, soil, or/and
complexed with humic substances (HSs).
The amount of free enzymes is much lower in the soil solution than in the
adsorbed and/or complexed state. Enzymatic activities (EAs) in the [nmol/min/mg]
soil plays a role in decomposition and mineralization processes.
The main method by which this problem is studied is based on the comparison of
the transformation of the enzyme substrate in the soil samples containing
proliferating MOs with that of samples of the same soil, where the proliferation of
the MOs was stopped. Soil is an enzymatic system where the accumulated enzymes
and enzymes of the proliferating MOs have biological significance, participating in
the biological cycles of the elements and contributing to the fertility of the soil,
creating favorable conditions for the nutrition of the superior plants, and, implicitly,
perpetuating life on our planet (Wang et al. 2013).
4.2.2 The Importance of Soil Microorganisms for Biological
Depollution
A dynamic soil quality parameter is the activity of biodegradation and mineralization
of organic soil substances. This includes carbohydrate biodegradation (decomposition of cellulose, glucose, pectic substances, starch, chitin, lignin, etc.) and biodegradation of aliphatic hydrocarbons (methane, ethane, propane, etc.), and aromatic
(benzene, toluene, etc.). Processes such as lipid decomposition, pesticide biodegradation and decomposition of proteins from plant debris, animals and MOs, and
organic nitrogen compounds occur in the presence of soil macroorganisms. The
microbial population of the soil is made up of representatives of all MOs: bacteria,
actinomycetes, fungi (micromycetes, yeasts), microscopic algae and protozoa, and
soil viruses, also. Bacteria are the most important group of soil MOs. The intensity of
processes by which MOs participate in the biological cycles of the elements is higher
in bacteria; the decomposition of chitin (a nitrogen-containing polysaccharide composed of fungi or insect exoskeleton), where the action of actinomycetes is more
intense; as well as the decomposition of lignin and cellulose in which the
4 Advanced Technologies for Ecological Reconstruction and Bioremediation of. . .
83
Natural Bioresources Involved in Bioremediation
4.2.1 Enzymatic Soil Activity
Enzymatic soil activity is a soil quality parameter and is the result of the activity of
accumulated enzymes and enzymes from proliferating MOs. The sources of the
enzymes accumulated in the soil are MOs cells and organic residues (vegetal and
animal). Enzymes accumulate in the soil as free enzymes (exoenzymes released from
living cells and endoenzymes released from disintegrated cells) and enzymes linked
to cellular constituents, i.e., enzymes present in disintegrating cells (in cellular
fragments) in living but nonproliferating cells.
Enzymes of proliferating MOs are both those that are released from living cells
undergoing multiplication as well as those found within cells undergoing multiplication. Free enzymes are adsorbed by organic and mineral particles, soil, or/and
complexed with humic substances (HSs).
The amount of free enzymes is much lower in the soil solution than in the
adsorbed and/or complexed state. Enzymatic activities (EAs) in the [nmol/min/mg]
soil plays a role in decomposition and mineralization processes.
The main method by which this problem is studied is based on the comparison of
the transformation of the enzyme substrate in the soil samples containing
proliferating MOs with that of samples of the same soil, where the proliferation of
the MOs was stopped. Soil is an enzymatic system where the accumulated enzymes
and enzymes of the proliferating MOs have biological significance, participating in
the biological cycles of the elements and contributing to the fertility of the soil,
creating favorable conditions for the nutrition of the superior plants, and, implicitly,
perpetuating life on our planet (Wang et al. 2013).
4.2.2 The Importance of Soil Microorganisms for Biological
Depollution
A dynamic soil quality parameter is the activity of biodegradation and mineralization
of organic soil substances. This includes carbohydrate biodegradation (decomposition of cellulose, glucose, pectic substances, starch, chitin, lignin, etc.) and biodegradation of aliphatic hydrocarbons (methane, ethane, propane, etc.), and aromatic
(benzene, toluene, etc.). Processes such as lipid decomposition, pesticide biodegradation and decomposition of proteins from plant debris, animals and MOs, and
organic nitrogen compounds occur in the presence of soil macroorganisms. The
microbial population of the soil is made up of representatives of all MOs: bacteria,
actinomycetes, fungi (micromycetes, yeasts), microscopic algae and protozoa, and
soil viruses, also. Bacteria are the most important group of soil MOs. The intensity of
processes by which MOs participate in the biological cycles of the elements is higher
in bacteria; the decomposition of chitin (a nitrogen-containing polysaccharide composed of fungi or insect exoskeleton), where the action of actinomycetes is more
intense; as well as the decomposition of lignin and cellulose in which the
4 Advanced Technologies for Ecological Reconstruction and Bioremediation of. . .
83