Bacilli-Mediated Degradation of Xenobiotic Compounds and Heavy Metals

Abstract

Xenobiotic compounds are man-made compounds and widely used in dyes, drugs, pesticides, herbicides, insecticides, explosives, and other industrial chemicals. These compounds have been released into our soil and water due to anthropogenic activities and improper waste disposal practices and cause serious damage to aquatic and terrestrial ecosystems due to their toxic nature. The United States Environmental Protection Agency (USEPA) has listed several toxic substances as priority pollutants. Bacterial remediation is identified as an emerging technique to remove these substances from the environment. Many bacterial genera are actively involved in the degradation of toxic substances. Among the bacterial genera, the members of the genus Bacillus have a great potential to degrade or transform various toxic substances. Many Bacilli have been isolated and characterized by their ability to degrade or transform a wide range of compounds including both naturally occurring substances and xenobiotic compounds. This review describes the biodegradation potentials of Bacilli toward various toxic substances, including 4-chloro-2-nitrophenol, insecticides, pesticides, herbicides, explosives, drugs, polycyclic aromatic compounds, heavy metals, azo dyes, and aromatic acids. Besides, the advanced technologies used for bioremediation of environmental pollutants using Bacilli are also briefly described. This review will increase our understanding of Bacilli -mediated degradation of xenobiotic compounds and heavy metals.

Recent Advanced Technologies for the Characterization of Xenobiotic-Degrading Microorganisms and Microbial Communities

“…Microbial remediation of xenobiotic compounds is regarded as a superficial, proficient, economically feasible approach that uses a wide range of microorganisms to consume organic pollutants as carbon or nitrogen supplements to sustain their developmental activities (Chen et al, 2013 ; Mahmoud, 2016 ; Arora et al, 2018 ; Ortiz-Hernandez et al, 2018 ; Siles and Margesin, 2018 ; Zhan et al, 2018 ; Bhatt et al, 2020b ). Microorganisms are ubiquitous in nature, and diverse microbial communities thrive in natural and extreme stress environments, including soil, water, the human gut, hydrothermal vents, acid mine runoff, and oil reservoirs (Cycoń and Piotrowska-Seget, 2016 ; Jalowiecki et al, 2016 ; Ding et al, 2017 ; Aguinga et al, 2018 ; Wang Y. F. et al, 2018 ; Zierer et al, 2018 ; Delegan et al, 2019 ; Arora, 2020 ; Shekhar et al, 2020 ). Microbial populations exhibit potential for the remediation of any contaminated environment because of their genetic diversity and functionality (Chen et al, 2015 ; Bastida et al, 2016 ; Bhatt and Barh, 2018 ; Dangi et al, 2018 ).…”

Degradation of benzo[a]pyrene by halophilic bacterial strain Staphylococcus haemoliticus strain 10SBZ1A

“…Polycyclic aromatic hydrocarbons (PAHs) are classified as low molecular weight PAHs, containing three or less fused benzene rings such as naphthalene, anthracene and phenanthrene, and high molecular weight PAHs (HMW-PAHs), consisting of four or more fused benzene rings, such as pyrene and benzo[a]pyrene (BaP) [ 6 ]. The biodegradation of HMW-PAHs is challenging, the higher the number of rings, the more difficult it is to degrade [ 7 ]. Because of its high ring number, BaP is one of the most recalcitrant PAHs to degradation, thus, it persists longer in the environment, with its attendant toxicity.…”

A New Ciboria sp. for Soil Mycoremediation and the Bacterial Contribution to the Depletion of Total Petroleum Hydrocarbons

“…Bacillus sp. is described for its capability to transform xenobiotics by the exploitation of intracellular and extracellular enzymatic machinery, associated to the capacity to produce biosurfactants ( Arora, 2020 ).…”