Mechanistic Insight to Bioremediation of Hazardous Metals and Pesticides from Water Bodies by Microbes (original) (raw)
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Heavy metal and pesticide pollution have become an inevitable part of the modern industrialized environment that find their way into all ecosystems. Because of their persistent nature, recalcitrance, high toxicity and biological enrichment, metal and pesticide pollution has threatened the stability of the environment as well as the health of living beings. Due to the environmental persistence of heavy metals and pesticides, they get accumulated in the environs and consequently lead to food chain contamination. Therefore, remediation of heavy metals and pesticide contaminations needs to be addressed as a high priority. Various physico-chemical approaches have been employed for this purpose, but they have significant drawbacks such as high expenses, high labor, alteration in soil properties, disruption of native soil microflora and generation of toxic by-products. Researchers worldwide are focusing on bioremediation strategies to overcome this multifaceted problem, i.e., the removal, ...
Recent Advancements in Bioremediation of Metal Contaminants
2021
Biofilms are an accumulation of single or various populations of microorganisms that are present on the surfaces through membrane-bound substances due to the gene expression, which differs from freefloating expression and leads to expressed genes regulating biofilm formation and development. In this regard, recent advances in microbial-based heavy metals have propelled bioremediation as a prospective alternative to conventional techniques. Adsorption and biodegradation of organic contaminants and the immobilization, mobilization, and/or transformation of metals are the main remediation processes that can be mediated by the action of several microorganisms surviving in hostile environments with high concentrations of pollutants. The chapter discussed the formation and regulation of biofilms to degrade the metal contaminant, the importance of gene transfer, and applications of biofilm-mediated bioremediation processes. Recent Advancements in Bioremediation of Metal Contaminants
Heavy metals are natural constituents of the environment, but indiscriminate use for human purposes has altered their geochemical cycles and biochemical balance. This results in excess release of heavy metals such as cadmium, copper, lead, nickel, zinc etc. into natural resources like the soil and aquatic environments. Prolonged exposure and higher accumulation of such heavy metals can have deleterious health effects on human life and aquatic biota. The role of microorganisms and plants in biotransformation of heavy metals into nontoxic forms is well-documented, and understanding the molecular mechanism of metal accumulation has numerous biotechnological implications for bioremediation of OPEN ACCESS Sustainability 2015, 7 2190 metal-contaminated sites. In view of this, the present review investigates the abilities of microorganisms and plants in terms of tolerance and degradation of heavy metals. Also, advances in bioremediation technologies and strategies to explore these immense and valuable biological resources for bioremediation are discussed. An assessment of the current status of technology deployment and suggestions for future bioremediation research has also been included. Finally, there is a discussion of the genetic and molecular basis of metal tolerance in microbes, with special reference to the genomics of heavy metal accumulator plants and the identification of functional genes involved in tolerance and detoxification.
Bioremediation of heavy metal ions from contaminated soil and water by microbes: A review
African Journal of Biological Sciences, 2021
Scientists all over the world are working tirelessly on the management of environmental toxicants and their control over the past two decades due to their injurious effects on plants, animals, and humans. These calcitrants released to the environment from both anthropogenic industries and natural sources can enter the food chain. The removal of such xenobiotic materials such as heavy metals from the soil and water around industrial areas has received great attention nowadays globally. It is, therefore; against this backdrop that this review research was conducted solely to establish the potentials of microorganisms (algae, fungi, bacteria, and plants) in the bio-removal of heavy metals contaminated soils and water. The study revealed that the use of these microbes in the decontamination of the environment cannot be overemphasized hence cost-effective, eco-friendly, and available almost everywhere on planet earth.
An overview on potential use of microorganisms for bioremediation of heavy metals
Journal of emerging technologies and innovative research, 2017
Heavy metals are persistent environmental pollutants that are introduced into the environment by natural processes and various anthropogenic activities. Environmental pollution caused by heavy metals has become a severe threat to environment and life causing serious health effects. Removal of heavy metals from the environment is a real challenge and over the years, various physiochemical methods were used for its removal. Recently, bioremediation approach involving microorganisms have gain interest and the new approach is widely used for treating heavy metals from contaminated environment. Bioremediation approach has many advantages over other conventional methods as it is environmental friendly, safe and easy to handle. Microorganisms play a significant role in heavy metal detoxification, however, due to dearth of knowledge on its molecular mechanism their application in the field of bioremediation has been limited. This review describes how bioremediation approach involving microorganisms as agents for elimination of toxic metals from contaminated sites. The present review also focuses on potential adverse effects on human health issues from long term exposure of heavy metals.
Microbial Bioremediation of Heavy Metals
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Heavy metals are persistent in nature and toxic to all life forms. Increase in industrialization, urbanization and unsafe agriculture practices is constantly adding heavy metals to the environment, and consequently causing heavy metal pollution of water and soil. Considering the negative impacts of heavy metals on the environment, several strategies have been devised to remediate them. However, most of these have their own limitations. Bioremediation of metals by microorganisms is efficient, cost-effective and environmentfriendly method of metal detoxification. Microbes can utilize metal contaminants as their energy source and transform them to less toxic forms. When exposed to metals for a considerable period of time, microorganisms interact with them and become tolerant by developing resistance mechanism against them. Metalmicrobe interactions can occur in several ways such as biosorption, bioleaching, biomineralization, bioaccumulation and biotransformation. Study of these interactions is important to understand resistance mechanisms against metals which include barriers, efflux system, sequestration and reduction of metals. These mechanisms are encoded by the resistance genes localized in chromosomes and plasmids. Understanding resistance mechanisms against metals in microorganisms becomes crucial for devising strategies for bioremediation of metals.
The potential of naturally occurring bacteria for the bioremediation of toxic metals pollution
Brazilian Journal of Biological Sciences
An increase in industrialization and various kind of human activities added a huge amount of toxic heavy metals in the soil. As a result, toxic heavy metals in the environment may be adversely affects human being and aquatic ecosystem. Thus, it is very essential to understand mechanism of bioremediation through eco-friendly agent i.e. bacteria. Accumulation of high metal concentrations in soil above threshold limit causes lethal to bacterial communities in the environment. Few bacteria develop resistance mechanism to tolerate these toxic heavy metals and contain various methods to respond the metal stress. The present review emphasizes to understand the mechanism of bacterial resistance against toxic metals. Moreover, mechanism of bioaugmentation, biosorption, and bioaccumulation methods also described clearly.
BIOREMEDIATION POTENTIAL OF MICROBES TOWARDS HEAVY METAL CONTAMINATION
An increase in the anthropogenic activities leading to environmental pollution has gained awareness worldwide. The pertinacious nature of heavy metals lead to adverse health effects towards the life of both plants and animals, further resulting in crucial diseases in humans. Bioremediation is considered one of the safer, cleaner, cost effective and environmentally sound technique for removal of contamination from such sites which are contaminated with extensive range of pollutants. Heavy metals are imperishable and can only be altered from one oxidation state to another. Natures innate recycling mechanism involves certains microorganisms, which have the potential to biotransform toxic metals into a lesser toxic form which is utilized as their energy source. Reducing the toxicity of soil and water contaminants, microorganisms including certain bacteria and fungi, also play a pivotal role in promoting growth of plants in contaminated sites. Certain plant growth promoting rhizomicrobes (PGPR) including bacillus, pseudomonads, mycobacterium etc., help in increased nutrient uptake, along with higher phosphate and nitrogen content of the plants. These rhizobacteria may also lead to metal mobilization and increase metal uptake by some plant species leading to microbe assisted phytoremediation of an environmentally polluted site. The present study highlights certain bioremediation mechanisms of microbes and their role in phytobial cleaning of the environment.