metabolic pathways necessitate the movement of electron from electron donors to
electron acceptors. It has been observed that the electron donor serves as substrates
and food for these microorganisms that could biodegrade but are normally restricted
in a non-polluted site. However, it has been stated that in polluted environment the
liberation of an organic electron donor may enhance microorganisms to strive for
any available acceptors to restore the balance of the system.
There are two types of bioremediation which depend on the location of the
contaminant treatment. If the methods to adopt involves in situ bioremediation, the
pollutant samples are treated in the original place of pollution but in ex situ
remediation, management of pollutants takes place typically off-site (Vogt and
Richnow 2014; Jorgensen 2007). It has been observed that in situ bioremediation
has several advantages which includes reduction on the cost of transportation and
disruption of sites. Moreover, it has been observed that optimization of chemical and
physical conditions might hasten the process of biodegradation by bacteria most
especially when supplemented by nutrients. Another effective way of biodegradation is to apply genetically engineered microorganisms which can modulate the
pathways for enhanced biodegradation of heavily polluted environment (Singh
et al. 2011; Hedlund and Staley 2001; Nakajima-Kambe et al. 2009).
Also, indigenous bacterial communities have been recognized to possess the
potential to metabolize any available heavy metals, and persistent organic pollutants
into a lesser toxic constitutes. The presence of limited nutrient and lack of adequate
access to these contaminants prevents these process involved in the reduction of
these pollutant available in the environment (de Lipthay et al. 2003; Petrie et al.
2003). It has been observed that biofilm and free-living planktonic bacteria could
metabolise toxic and pollutants in the environment. Some factors such as reduction
in protection, low bioavailability of the pollutants and reduced metabolic activity
might result in improper transformation mainly by planktonic bacteria (von Canstein
et al. 2002).
It has been observed that some bacterial community possess the capability to
biodegrade, neutralize and play active role in the mineralization of numerous
xenobiotic compounds in wastewater-activated sludge (Byrns 2001; Bertin et al.
2007). The application of biofilm has been identified as a sustainable and effective
means of detoxification of pollutant in the environment, and they also play a crucial
role in the protection of microbial diversity as well as enhance the increase in their
population (Boon et al. 2003; Accinelli et al. 2012).
The genus Dehalococcoides have been recognized for their potential to produce
biofilm with high application in the biofilm reactor community for the bioremediation of dechlorination of trichloroethene (Chung et al. 2007). Guezennec et al.
(2012) reported that the inactive oxidation of arsenic and iron by biofilms was
effective at gold-quartz mining sites while Williams et al. (2013) wrote that biofilm
in the tube could reduce the level of selenium concentration in the tubes having
nutrients. Also, Pool et al. (2013) also highlighted the significance of biofilm
enzymes and their application in the coal mine drainage regions when applied as
biomarkers for stream water quality.
9 Utilization of Microbial Biofilm for the Biotransformation and Bioremediation. . .
229
electron acceptors. It has been observed that the electron donor serves as substrates
and food for these microorganisms that could biodegrade but are normally restricted
in a non-polluted site. However, it has been stated that in polluted environment the
liberation of an organic electron donor may enhance microorganisms to strive for
any available acceptors to restore the balance of the system.
There are two types of bioremediation which depend on the location of the
contaminant treatment. If the methods to adopt involves in situ bioremediation, the
pollutant samples are treated in the original place of pollution but in ex situ
remediation, management of pollutants takes place typically off-site (Vogt and
Richnow 2014; Jorgensen 2007). It has been observed that in situ bioremediation
has several advantages which includes reduction on the cost of transportation and
disruption of sites. Moreover, it has been observed that optimization of chemical and
physical conditions might hasten the process of biodegradation by bacteria most
especially when supplemented by nutrients. Another effective way of biodegradation is to apply genetically engineered microorganisms which can modulate the
pathways for enhanced biodegradation of heavily polluted environment (Singh
et al. 2011; Hedlund and Staley 2001; Nakajima-Kambe et al. 2009).
Also, indigenous bacterial communities have been recognized to possess the
potential to metabolize any available heavy metals, and persistent organic pollutants
into a lesser toxic constitutes. The presence of limited nutrient and lack of adequate
access to these contaminants prevents these process involved in the reduction of
these pollutant available in the environment (de Lipthay et al. 2003; Petrie et al.
2003). It has been observed that biofilm and free-living planktonic bacteria could
metabolise toxic and pollutants in the environment. Some factors such as reduction
in protection, low bioavailability of the pollutants and reduced metabolic activity
might result in improper transformation mainly by planktonic bacteria (von Canstein
et al. 2002).
It has been observed that some bacterial community possess the capability to
biodegrade, neutralize and play active role in the mineralization of numerous
xenobiotic compounds in wastewater-activated sludge (Byrns 2001; Bertin et al.
2007). The application of biofilm has been identified as a sustainable and effective
means of detoxification of pollutant in the environment, and they also play a crucial
role in the protection of microbial diversity as well as enhance the increase in their
population (Boon et al. 2003; Accinelli et al. 2012).
The genus Dehalococcoides have been recognized for their potential to produce
biofilm with high application in the biofilm reactor community for the bioremediation of dechlorination of trichloroethene (Chung et al. 2007). Guezennec et al.
(2012) reported that the inactive oxidation of arsenic and iron by biofilms was
effective at gold-quartz mining sites while Williams et al. (2013) wrote that biofilm
in the tube could reduce the level of selenium concentration in the tubes having
nutrients. Also, Pool et al. (2013) also highlighted the significance of biofilm
enzymes and their application in the coal mine drainage regions when applied as
biomarkers for stream water quality.
9 Utilization of Microbial Biofilm for the Biotransformation and Bioremediation. . .
229