28
K. KirupaSree et al.
bacteria are observed due to presence of phospholipids and LPS which favours the
phenomenon of adsorption (Gourdon et al. 1990; Das et al. 2008). Microorganisms
have advanced mechanisms to protect themselves from the toxic doses of heavy
metals such as adsorption, oxidation/reduction, or methylation. These mechanisms
can be adopted with some manipulation in treatment strategies for the removal of
metals from polluted environments (Hashim et al. 2011).
5 Applications and Future Prospects
Detection of novel genes and proteins associated with the ability of eco-friendly
clean-up will be a great benefit to achieve enhanced bioremediation. To identify new
genes which may be expressed in the presence of a particular heavy metal pollutant, gene expression studies employing microarray technology and whole genome
sequencing assays shall be worthwhile. Microbes possess many unique characteristic
features such as biofilm formation, biosurfactant productions, secondary metabolites
synthesis, and many more to withstand the adverse conditions in the environment.
These properties of metal resistant bacteria may be harnessed for their enhanced
utilization in bioremediation. Recently, multispecies biofilm communities have been
explored for their metal tolerance and bio-mineralization properties (Golby et al.
2014). Though bacteria develop metal-resistant phenotypes and genotypes as a mode
of adaptation in the contaminated environments, the gene pool of these resistant
bacteria can be a choice of research thirst in near future to have a proper insight into
the molecular genetics approaches for an enhanced heavy metal bioremediation so
as to save the environment.
6 Conclusion
This chapter revealed both the active (Bioaccumulation) and passive (Biosorption)
mechanisms of bioremoval of toxic heavy metals by Heavy metal tolerant-plant
growth promoting rhizobacteria. These communities are widely involved in the
removal of heavy metals from the polluted environment. At this juncture, Bacterial siderophores gain importance because of their capability to interact with the
heavy metals like Fe, Ni, Cd, Cu, and Zn. In which the metal uptake is concerned
through two special proteins. They are metallo-proteins or metal-binding proteins
and peptides. The use of PGPR for plant growth improvement is presently receiving
substantial worldwide concentration and the latest successive PGPR researches have
exhibit luminous prospects for bioremediation of polluted soil environments. In addition, the rapid development of molecular biological methods is bringing valuable
advantages to identify and enhance the rhizobacterial traits involved in heavy metal
bioremoval from the areas under heavy metal stress.
K. KirupaSree et al.
bacteria are observed due to presence of phospholipids and LPS which favours the
phenomenon of adsorption (Gourdon et al. 1990; Das et al. 2008). Microorganisms
have advanced mechanisms to protect themselves from the toxic doses of heavy
metals such as adsorption, oxidation/reduction, or methylation. These mechanisms
can be adopted with some manipulation in treatment strategies for the removal of
metals from polluted environments (Hashim et al. 2011).
5 Applications and Future Prospects
Detection of novel genes and proteins associated with the ability of eco-friendly
clean-up will be a great benefit to achieve enhanced bioremediation. To identify new
genes which may be expressed in the presence of a particular heavy metal pollutant, gene expression studies employing microarray technology and whole genome
sequencing assays shall be worthwhile. Microbes possess many unique characteristic
features such as biofilm formation, biosurfactant productions, secondary metabolites
synthesis, and many more to withstand the adverse conditions in the environment.
These properties of metal resistant bacteria may be harnessed for their enhanced
utilization in bioremediation. Recently, multispecies biofilm communities have been
explored for their metal tolerance and bio-mineralization properties (Golby et al.
2014). Though bacteria develop metal-resistant phenotypes and genotypes as a mode
of adaptation in the contaminated environments, the gene pool of these resistant
bacteria can be a choice of research thirst in near future to have a proper insight into
the molecular genetics approaches for an enhanced heavy metal bioremediation so
as to save the environment.
6 Conclusion
This chapter revealed both the active (Bioaccumulation) and passive (Biosorption)
mechanisms of bioremoval of toxic heavy metals by Heavy metal tolerant-plant
growth promoting rhizobacteria. These communities are widely involved in the
removal of heavy metals from the polluted environment. At this juncture, Bacterial siderophores gain importance because of their capability to interact with the
heavy metals like Fe, Ni, Cd, Cu, and Zn. In which the metal uptake is concerned
through two special proteins. They are metallo-proteins or metal-binding proteins
and peptides. The use of PGPR for plant growth improvement is presently receiving
substantial worldwide concentration and the latest successive PGPR researches have
exhibit luminous prospects for bioremediation of polluted soil environments. In addition, the rapid development of molecular biological methods is bringing valuable
advantages to identify and enhance the rhizobacterial traits involved in heavy metal
bioremoval from the areas under heavy metal stress.