the multifunctional P-450 enzyme system with the addition of one oxygen atom
across a double bond. The epoxides formed on this way have a short lifetime and
may be transformed into phenols or hydrolyzed to dihydrodiols. The products may
be conjugated with glutathione, glucuronic acid, or sulfuric acid, and after further
transformation be excreted outside the microbial cell (Cerniglia 1992; Xu and Lu
2010).
5.3 The Use of Organic Matter in Bioremediation and Its
Environmental Implication
5.3.1 Nutrient Source for Bioremediation
Solid organic waste originating from agricultural or municipal sources constitutes a
valuable amendment for TPH biodegradation. The use of organic waste in soil
bioremediation is economically reasonable as production of inorganic fertilizers is
costly and energy consuming and in contrast to organic wastes does not provide
additional benefits to soil in a long term (Steiner et al. 2007). Inorganic amendments
are soluble in water and quickly consumed by microorganisms and plants. Mature
organic amendments are more stable because of low solubility and low biodegradability. Moreover, addition of organic matter into soil contributes to the turnover of
carbon and nutrients in SOM. Addition of organic nutrient has also a positive impact
on the improvement of soil physical and chemical characteristics such as aeration,
structure, pH neutralization, and total organic carbon maintenance (Nardi et al.
2004). Improved soil parameters contribute to creation and maintenance of suitable
condition for well-functioning of microbial societies (Masciandaro et al. 2013).
In many studies regarding soil composting performed at laboratory scale
(Table 5.3), addition of organic matter to contaminated soil was shown to significantly improve the rate of hydrocarbon biodegradation (Namkoong et al. 2002;
Juteau et al. 2003; Kriipsalu et al. 2007; Sayara et al. 2010c). In order to compare
the effectiveness of different nutrient sources, Table 5.3 also presents details regarding studies reporting on the use of mineral fertilizers (Lamy et al. 2013; Sutton et al.
2013; Mihial et al. 2006). To obtain optimal conditions for microbial development,
the use of nutrient in bioremediation treatments was combined with the application
of bulking agent, e.g., straws, wood chips, gravel grass clippings (Mihial et al. 2006;
Sayara et al. 2010c). This additional amendment allows improving oxygen diffusion
into the composting mixture, thus enhancing the activity of aerobic bacteria.
Different benefits may be obtained depending on the bulking agent selected. For
example, it was observed that peanut hull powder added to hydrocarboncontaminated soil acted as a bio-carrier, improving the mass transfer of water,
oxygen, nutrients, and contaminants, and also constituted an additional nutrient
source for microflora (Xu and Lu 2010). The effect of bulking agents such as pine
shavings, chopped grass, and wheat straw on C:N ratio during composting with
5 Potential Use of Waste-to-Bioenergy By-Products in Bioremediation of Total. . .
257
across a double bond. The epoxides formed on this way have a short lifetime and
may be transformed into phenols or hydrolyzed to dihydrodiols. The products may
be conjugated with glutathione, glucuronic acid, or sulfuric acid, and after further
transformation be excreted outside the microbial cell (Cerniglia 1992; Xu and Lu
2010).
5.3 The Use of Organic Matter in Bioremediation and Its
Environmental Implication
5.3.1 Nutrient Source for Bioremediation
Solid organic waste originating from agricultural or municipal sources constitutes a
valuable amendment for TPH biodegradation. The use of organic waste in soil
bioremediation is economically reasonable as production of inorganic fertilizers is
costly and energy consuming and in contrast to organic wastes does not provide
additional benefits to soil in a long term (Steiner et al. 2007). Inorganic amendments
are soluble in water and quickly consumed by microorganisms and plants. Mature
organic amendments are more stable because of low solubility and low biodegradability. Moreover, addition of organic matter into soil contributes to the turnover of
carbon and nutrients in SOM. Addition of organic nutrient has also a positive impact
on the improvement of soil physical and chemical characteristics such as aeration,
structure, pH neutralization, and total organic carbon maintenance (Nardi et al.
2004). Improved soil parameters contribute to creation and maintenance of suitable
condition for well-functioning of microbial societies (Masciandaro et al. 2013).
In many studies regarding soil composting performed at laboratory scale
(Table 5.3), addition of organic matter to contaminated soil was shown to significantly improve the rate of hydrocarbon biodegradation (Namkoong et al. 2002;
Juteau et al. 2003; Kriipsalu et al. 2007; Sayara et al. 2010c). In order to compare
the effectiveness of different nutrient sources, Table 5.3 also presents details regarding studies reporting on the use of mineral fertilizers (Lamy et al. 2013; Sutton et al.
2013; Mihial et al. 2006). To obtain optimal conditions for microbial development,
the use of nutrient in bioremediation treatments was combined with the application
of bulking agent, e.g., straws, wood chips, gravel grass clippings (Mihial et al. 2006;
Sayara et al. 2010c). This additional amendment allows improving oxygen diffusion
into the composting mixture, thus enhancing the activity of aerobic bacteria.
Different benefits may be obtained depending on the bulking agent selected. For
example, it was observed that peanut hull powder added to hydrocarboncontaminated soil acted as a bio-carrier, improving the mass transfer of water,
oxygen, nutrients, and contaminants, and also constituted an additional nutrient
source for microflora (Xu and Lu 2010). The effect of bulking agents such as pine
shavings, chopped grass, and wheat straw on C:N ratio during composting with
5 Potential Use of Waste-to-Bioenergy By-Products in Bioremediation of Total. . .
257