Bioremediation of Recalcitrant Xenobiotic Compounds: Advancements and Challenges

Widespread recalcitrant xenobiotic compounds have posed serious environmental threats. These compounds are known to contaminate groundwater, crops, water bodies, and lands, affecting the lives of people living nearby. Sites polluted with organic contaminants like polycyclic aromatic hydrocarbons (PAHs), chlorinated hydrocarbons (CHC), phenols, and aromatic hydrocarbons (benzene-toluene-ethylbenzene-xylenes, BTEX) are located worldwide, in both developed and developing countries. Many pollutants have been classified as persistent organic pollutants (POPs) whose production and usage have been either limited or banned by the Stockholm Convention. In May 2001, the Stockholm Convention gave a list of 12 POPs and called them “dirty dozens,” which has now increased to 36 POPs. Much advancement has been made in the last decade; however, on-field bioremediation techniques are still not well developed. Detection of ongoing remediation in trials by using metagenomics, metatranscriptomics, metabolomics, and metaproteomics produces huge data sets. These in-silico analyses required efficient algorithms and skilled professionals to contemplate data analyses. Carbon-stable isotope analysis, microarrays, and high-throughput cultivation techniques are also promising methods that have helped researchers track bioremediation. However, challenges faced by the scientific community are numerous, which has affected the pace of advancements in achieving a defined strategy for bioremediation of xenobiotic compounds. This review summarises the need for remediation of recalcitrant xenobiotic compounds that pose a threat to the environment and human health. Also, advancements made in the field of bioremediation and the problems posed in the implementation of designed strategies have been summed up.