co-contaminated soils. Eventually, the bioaugmentation approach may be contingent
on the amount of contamination and the period frame obtainable for remediation.
Burghal et al. (2015) evaluated the effect of autochthonous microflora for the
bioaugmentation of hydrocarbon polluted soil after it has been biostimulated by the
mixture of sheep and cow dung in the presence of sawdust. The experiment was
carried out in a test biopile containing contaminated soil entailing petroleum waste
100 kg together with 1.5% sawdust as well as necessary minerals and water that
improve the growth of necessary microorganisms. Aeration was supplied to the pile
by drainage-pipe network to enhance the process of bioaugmentation for a period of
90 days. It was established that there was alteration in the bacterial communities and
the total petroleum hydrocarbons. There was also a drastic decrease in the total level
of total petroleum hydrocarbons from 52 to 10.6 g kg
À1 . It was also revealed that the
dominant microorganism available in the soil entails autochthonous microorganisms
and Gram-positive bacteria mainly from actinomycete group that possess the capability to biodegrade to the maximum level of 1.6 Â 10
7 cfu g
À1 at 45 days. Their
study revealed that ex situ (biopile) experiment was the best approaches because it is
cost-effective, eco-friendly, sustainable for effective bioremediation of polluted soil.
The list of numerous microorganism utilized for bioaugmentation purposes are listed
in Table 15.1.
15.2.1 Specific Gene Involved in Bioaugmentation
It has been recognized that most of the microorganisms utilized for the process of
bioaugmentation do not survive. They have introduced the application of natural
gene transfer so as to establish the transfers of remediation genes into polluted
environment. The introduction of recent advances like genome sequencing has
helped in rapid advancement in the establishment of the role of horizontal gene
transfer played in the bioremediation of heavily polluted environment (Ochman et al.
2000). The movement of horizontal gene transfer may take place through the process
of transformation or conjugation which involves the conjugative transposons
between microorganisms or exchange of genetic material or physical contact such
as plasmids, transduction which involves mediation by bacteriophage, and the
application of gene bioaugmentation which involves several remediation genes
that are available in mobile form that could be liked to self-transmissible plasmid
when compared to the out-of-date cell bioaugmentation techniques involved.
(1) There is no necessity for long-term persistence of the introduced host strain.
(2) Release of remediation genes into local microorganisms could endure and
increase in the environment. It has been observed that the movement of plasmids
through conjugation is the technology mostly premeditated with reverence to
bioaugmentation (Christensen et al. 1998; Dejonghe et al. 2000; DiGiovanni et al.
1996; Herrick et al. 1997; Newby et al. 2000a, b; Top et al. 1999, 2002, 1998).
Newby et al. (2000a, b) evaluated the level of bioaugmentation within two
various bacterial donors that possess the capability of conveying the
386
C. O. Adetunji and O. A. Anani
on the amount of contamination and the period frame obtainable for remediation.
Burghal et al. (2015) evaluated the effect of autochthonous microflora for the
bioaugmentation of hydrocarbon polluted soil after it has been biostimulated by the
mixture of sheep and cow dung in the presence of sawdust. The experiment was
carried out in a test biopile containing contaminated soil entailing petroleum waste
100 kg together with 1.5% sawdust as well as necessary minerals and water that
improve the growth of necessary microorganisms. Aeration was supplied to the pile
by drainage-pipe network to enhance the process of bioaugmentation for a period of
90 days. It was established that there was alteration in the bacterial communities and
the total petroleum hydrocarbons. There was also a drastic decrease in the total level
of total petroleum hydrocarbons from 52 to 10.6 g kg
À1 . It was also revealed that the
dominant microorganism available in the soil entails autochthonous microorganisms
and Gram-positive bacteria mainly from actinomycete group that possess the capability to biodegrade to the maximum level of 1.6 Â 10
7 cfu g
À1 at 45 days. Their
study revealed that ex situ (biopile) experiment was the best approaches because it is
cost-effective, eco-friendly, sustainable for effective bioremediation of polluted soil.
The list of numerous microorganism utilized for bioaugmentation purposes are listed
in Table 15.1.
15.2.1 Specific Gene Involved in Bioaugmentation
It has been recognized that most of the microorganisms utilized for the process of
bioaugmentation do not survive. They have introduced the application of natural
gene transfer so as to establish the transfers of remediation genes into polluted
environment. The introduction of recent advances like genome sequencing has
helped in rapid advancement in the establishment of the role of horizontal gene
transfer played in the bioremediation of heavily polluted environment (Ochman et al.
2000). The movement of horizontal gene transfer may take place through the process
of transformation or conjugation which involves the conjugative transposons
between microorganisms or exchange of genetic material or physical contact such
as plasmids, transduction which involves mediation by bacteriophage, and the
application of gene bioaugmentation which involves several remediation genes
that are available in mobile form that could be liked to self-transmissible plasmid
when compared to the out-of-date cell bioaugmentation techniques involved.
(1) There is no necessity for long-term persistence of the introduced host strain.
(2) Release of remediation genes into local microorganisms could endure and
increase in the environment. It has been observed that the movement of plasmids
through conjugation is the technology mostly premeditated with reverence to
bioaugmentation (Christensen et al. 1998; Dejonghe et al. 2000; DiGiovanni et al.
1996; Herrick et al. 1997; Newby et al. 2000a, b; Top et al. 1999, 2002, 1998).
Newby et al. (2000a, b) evaluated the level of bioaugmentation within two
various bacterial donors that possess the capability of conveying the
386
C. O. Adetunji and O. A. Anani