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Review
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Microbial transformation
of xenobiotics for environmental bioremediation
Shelly Sinha1, Pritam Chattopadhyay2,
Ieshita Pan1, Sandipan Chatterjee1,
Pompee Chanda1, Debashis Bandyopadhyay1,
Kamala Das1 and Sukanta K. Sen1*
1Microbiology
Division, Department of Botany, Visva-Bharati, Santiniketan,
731 235, India.
2Plant
Biotechnology Division, Department of Botany, Visva-Bharati,
Santiniketan, 731 235, India.
*Corresponding author. E-mail:
sksenvb@rediffmail.com.
Accepted
4 September, 2009 |
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Abstract |
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The accumulation of recalcitrant xenobiotic compounds is due
to continuous efflux from population and industrial inputs
that have created a serious impact on the pristine nature of
our environment. Apart from this, these compounds are mostly
carcinogenic, posing health hazards which persist over a
long period of time. Metabolic pathways and specific
operon systems have been found in diverse
but limited groups of microbes that are responsible for the
transformation of xenobiotic compounds. Distinct catabolic
genes are either present on mobile genetic elements, such as
transposons and plasmids, or the chromosome itself that
facilitates horizontal gene transfer and enhances the rapid
microbial transformation of toxic xenobiotic compounds.
Biotransformation of xenobiotic compounds in natural
environment has been studied to understand the microbial
ecology, physiology and evolution for their potential in
bioremediation. Recent advance in the molecular techniques
including DNA fingerprinting, microarrays and metagenomics
is being used to augment the transformation of xenobiotic
compounds. The present day understandings of aerobic,
anaerobic and reductive biotransformation by co-metabolic
processes and an overview of latest developments in
monitoring the catabolic genes of xenobiotic-degrading
bacteria are discussed elaborately in this work. Till date,
several reviews have come up, highlighting the problem of
xenobiotic pollution, yet a comprehensive understanding of
the microbial biodegradation of xenobiotics and its
application is in nascent stage. Therefore, this is an
attempt to understand the microbial role in
biotransformation of xenobiotic compounds in context to the
modern day biotechnology.
Key
words:
Xenobiotics, degradation, bioremediation, co-metabolism,
catabolic genes, plasmid, transposon, horizontal gene
transfer. |
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