Biomedical Engineering Reference
In-Depth Information
plant root exudates encouraged microbial growth, leading to better bioremediation by those
bacteria (Gentry et al.,
2004
; Kuiper et al.,
2004
). In return, microbial products such as
surfactants and siderophores can enhance metal mobility and plant uptake (Zaidi et al.,
2006
;
Lebeau et al.,
2008
).
Phytoaugmentation is the addition of bacterial genes into plants to confer degradation
capacities (Gentry et al.,
2004
). These transgenic plants offer the benefits of phytoremediation,
such as an extensive root system that can process large amounts of pollutant and the ability to
sequester pollutants. They also can degrade compounds more thoroughly than non-modified
plants. While this technology has not yet been marketed, there are a wide variety of pollutants
that can be targeted (Abhilash et al.,
2009
; Sylvestre et al.,
2009
; Van Aken,
2009
).
1.3.2 Potential Bioaugmentation Strategies
Bioaugmentation is a rapidly developing field of study, as evidenced by the growing number
of publications over the last decade (Figure
1.4
). Many of these publications focus on the future
of bioaugmentation and what new techniques can be used to improve bioaugmentation success.
Some astounding and promising discoveries have been made, especially with the rapid progress
in molecular biology capabilities and the genetic manipulation of microorganisms. Some of the
bioaugmentation methods that have been proposed but not yet widely implemented in the field
are discussed below.
1.3.2.1 Genetically Engineered Microorganisms
In the event that an appropriate pollutant-degrading strain does not exist or results in toxic
or dead-end metabolites, there is the option of adding GEMs, in which genes are either
introduced into a host microbe or existing genes in a bacterium are altered (Garbisu and
Alkorta,
1999
; Sayler and Ripp,
2000
; Gentry et al.,
2004
; Khomenkov et al.,
2008
).
Bioaugmentation Publications (1990 - 2007)
100
91
90
80
76
70
66
70
63
61
60
46
50
38
40
27
30
25
20
19
20
11
11
10
4
3
3
2
0
Year
Figure 1.4. Number of international bioaugmentation publications (1991-2007) (adapted from the
Science Citation Index).
Search WWH ::
Custom Search