contaminated areas such as soil and solid waste materials such as sludge, industrial
effluents, etc. According to Huang et al. (1991), in bioremediation, organic and
inorganic pollutants are biologically degraded or transformed into innocuous materials naturally or by adding bioremediation-promoting components such as electron
acceptor, nutrients, etc.
Bioremediation techniques are more advantageous compared to conventional
methods as it can be implemented on site, therefore, minimizing personnel risks,
and sludge disposal problems due to the generation of less effluent volume when
compared to traditional approaches (Yadav et al. 2017). It is reported in the literature
that many organisms such as bacteria, fungi, and algae have the ability to degrade,
transform, or chelate the dye pollutants into harmless or less toxic components either
naturally or by genetic modification (Mosa et al. 2016). Bioremediation process is a
very effective approach due to the ability of microorganisms to interact with various
types of pollutants. Microorganisms used in bioremediation can transform dye
pollutants from one oxidative state to another; thus, it reduces the toxic effects of
the pollutants. Bioremediation through microbial metabolism offers a viable, safer,
efficient, and less expensive method for the removal of pollutants.
3 Microorganisms Used in Bioremediation
In recent years, research on the utilization of microorganisms in bioremediation for
the treatment of textile dye effluents has been in focus. Various studies reported the
mechanisms of bioremediation of dye effluents using microorganisms such as
bacteria, fungi, and algae. Studies were also conducted on the ability of living and
nonliving organisms, chemically and physically treated organisms, and genetically
modified organisms in bioremediation of dyes. In bioremediation, both microorganisms present in the contaminated area and microorganisms isolated from the other
sites can be used. This allows the use of a wide variety of microbes for the dye
removal process. However, studies reported that microorganisms existing in the
contaminated area showed high tolerance towards environmental fluctuations and
high ability in removing dyes from the effluents. Several studies showed that many
microorganisms could tolerate the heavy metals present in dye effluents and are able
to degrade them into less toxic components or completely eliminate them by
utilizing them for growth metabolic processes (Qazilbash 2004).
Microbial resistance and tolerance towards metal ions in dye effluents are very
important parameters in the success of bioremediation process since these microbes
have close contact with the pollutants for long durations during the degradation of
pollutants. The heavy metal resistance of microorganisms helps in the bioremediation process in two ways; first is by reducing the concentration of metal ions through
the elimination of metal-chelating substances or by the breakdown of a specific
transport mechanism. Second is by the binding of ions on the intracellular microbial
cells (Joho et al. 1995).
176
N. S. KV
effluents, etc. According to Huang et al. (1991), in bioremediation, organic and
inorganic pollutants are biologically degraded or transformed into innocuous materials naturally or by adding bioremediation-promoting components such as electron
acceptor, nutrients, etc.
Bioremediation techniques are more advantageous compared to conventional
methods as it can be implemented on site, therefore, minimizing personnel risks,
and sludge disposal problems due to the generation of less effluent volume when
compared to traditional approaches (Yadav et al. 2017). It is reported in the literature
that many organisms such as bacteria, fungi, and algae have the ability to degrade,
transform, or chelate the dye pollutants into harmless or less toxic components either
naturally or by genetic modification (Mosa et al. 2016). Bioremediation process is a
very effective approach due to the ability of microorganisms to interact with various
types of pollutants. Microorganisms used in bioremediation can transform dye
pollutants from one oxidative state to another; thus, it reduces the toxic effects of
the pollutants. Bioremediation through microbial metabolism offers a viable, safer,
efficient, and less expensive method for the removal of pollutants.
3 Microorganisms Used in Bioremediation
In recent years, research on the utilization of microorganisms in bioremediation for
the treatment of textile dye effluents has been in focus. Various studies reported the
mechanisms of bioremediation of dye effluents using microorganisms such as
bacteria, fungi, and algae. Studies were also conducted on the ability of living and
nonliving organisms, chemically and physically treated organisms, and genetically
modified organisms in bioremediation of dyes. In bioremediation, both microorganisms present in the contaminated area and microorganisms isolated from the other
sites can be used. This allows the use of a wide variety of microbes for the dye
removal process. However, studies reported that microorganisms existing in the
contaminated area showed high tolerance towards environmental fluctuations and
high ability in removing dyes from the effluents. Several studies showed that many
microorganisms could tolerate the heavy metals present in dye effluents and are able
to degrade them into less toxic components or completely eliminate them by
utilizing them for growth metabolic processes (Qazilbash 2004).
Microbial resistance and tolerance towards metal ions in dye effluents are very
important parameters in the success of bioremediation process since these microbes
have close contact with the pollutants for long durations during the degradation of
pollutants. The heavy metal resistance of microorganisms helps in the bioremediation process in two ways; first is by reducing the concentration of metal ions through
the elimination of metal-chelating substances or by the breakdown of a specific
transport mechanism. Second is by the binding of ions on the intracellular microbial
cells (Joho et al. 1995).
176
N. S. KV