Microbial and Plant-Assisted Bioremediation of Heavy Metal Polluted Environments: A Review
04 Dec 2017-International Journal of Environmental Research and Public Health (Multidisciplinary Digital Publishing Institute (MDPI))-Vol. 14, Iss: 12, pp 1504
TL;DR: The toxic effects of heavy metal pollution and the mechanisms used by microbes and plants for environmental remediation are discussed and the importance of modern biotechnological techniques and approaches in improving the ability of microbial enzymes to effectively degrade heavy metals at a faster rate is emphasized.
Abstract: Environmental pollution from hazardous waste materials, organic pollutants and heavy metals, has adversely affected the natural ecosystem to the detriment of man. These pollutants arise from anthropogenic sources as well as natural disasters such as hurricanes and volcanic eruptions. Toxic metals could accumulate in agricultural soils and get into the food chain, thereby becoming a major threat to food security. Conventional and physical methods are expensive and not effective in areas with low metal toxicity. Bioremediation is therefore an eco-friendly and efficient method of reclaiming environments contaminated with heavy metals by making use of the inherent biological mechanisms of microorganisms and plants to eradicate hazardous contaminants. This review discusses the toxic effects of heavy metal pollution and the mechanisms used by microbes and plants for environmental remediation. It also emphasized the importance of modern biotechnological techniques and approaches in improving the ability of microbial enzymes to effectively degrade heavy metals at a faster rate, highlighting recent advances in microbial bioremediation and phytoremediation for the removal of heavy metals from the environment as well as future prospects and limitations. However, strict adherence to biosafety regulations must be followed in the use of biotechnological methods to ensure safety of the environment.
Citations
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TL;DR: Soil heavy metal pollution has become a worldwide environmental issue that has attracted considerable public attention as mentioned in this paper, largely from the increasing concern for the security of agricultural products and the need to protect the environment.
Abstract: Soil heavy metal pollution has become a worldwide environmental issue that has attracted considerable public attention, largely from the increasing concern for the security of agricultural products...
335 citations
Cites background from "Microbial and Plant-Assisted Biorem..."
...…and cost-effective technique for heavy metal removal compared with the conventional chemical and physical methods, which are often very expensive and ineffective especially for low metal concentrations, in addition to producing significant amounts of toxic sludge (Ojuederie and Babalola, 2017)....
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...of heavy metals from contaminated soils include microorganisms through the processes of precipitation, biosorption via sequestration by intracellular metal binding proteins, and conversion of metals to innocuous forms by enzymes (Ojuederie and Babalola, 2017)....
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...significant amounts of toxic sludge (Ojuederie and Babalola, 2017)....
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...The mechanisms used in remediation of heavy metals from contaminated soils include microorganisms through the processes of precipitation, biosorption via sequestration by intracellular metal binding proteins, and conversion of metals to innocuous forms by enzymes (Ojuederie and Babalola, 2017)....
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TL;DR: In this article, the authors discuss some of the most recent and relevant findings related to the release of heavy metals, the possible risks for the environment and human health, the materials and technologies available for their removal.
Abstract: Water pollution is one of the global challenges that society must address in the 21st century aiming to improve water quality and reduce human and ecosystem health impacts. Industrialization, climate change, and expansion of urban areas produce a variety of water pollutants. In this work, we discuss some of the most recent and relevant findings related to the release of heavy metals, the possible risks for the environment and human health, the materials and technologies available for their removal. Anthropogenic activities are identified as the main source of the increasing amounts of heavy metals found in aquatic environments. Some of the health hazards derived from repeated exposure to traces of heavy metals, including lead, cadmium, mercury, and arsenic, are outlined. We also give some perspectives about several techniques used to detect heavy metals, as well as about the factors that could affect the contaminant removal. The advantages and drawbacks of conventional and non-conventional heavy metal removal methods are critically discussed, given particular attention to those related to adsorption, nanostructured materials and plant-mediated remediation. Some of the commercial products currently used to eliminate heavy metals from water are also listed. Finally, we point out some the requirements and opportunities linked to developing efficient methods for heavy metal removal, such as the ones that exploit nanotechnologies.
294 citations
TL;DR: In this article, the authors reviewed the bioremediation applications of combined contaminated soil with heavy metals and pesticides and proposed the future investigations required for this field, based on which the effectiveness evaluation methods of soil remediation are also reviewed.
190 citations
Posted Content•
TL;DR: The mechanism of biosorption is complex, mainly ion exchange, chelation, adsorption by physical forces, entrapment in inter and intrafibrilliar capillaries and spaces of the structural polysaccharide network as a result of the concentration gradient and diffusion through cell walls and membranes as discussed by the authors.
Abstract: Metallic species mobilized and released into the environment by the technological activities of human tend to persist indefinitely, circulating and eventually accumulating throughout the food chain, thus posing a serious threat to the environment, animals and humans. It is essential to realize that the metal is only removed from solution when it is appropriately immobilized. Apart from slow natural process of metal mineralization, ultimate removal is attained only when the metal becomes concentrated to the point that it can be either returned to the process or resold. The metallic pollutants can be sorbed by biosorbant material. The mechanism of biosorption is complex, mainly ion exchange, chelation, adsorption by physical forces, entrapment in inter and intrafibrilliar capillaries and spaces of the structural polysaccharide network as a result of the concentration gradient and diffusion through cell walls and membranes. Due to the extensive research and significant economic benefits of biosorption, some new biosorbant resources are poised for commercial exploitation.
176 citations
TL;DR: There are distinctive subsets of phytoremediation; the most successfully utilized ones are (a) Phytostabilization (b) Rhizodegradation (c) RHizofiltration (d), Phytodegradions (e) Phytoextraction (f) PhYtoaccumulation (g) and Phytovolatilization.
Abstract: Pollutants is one of the ecological contaminations for the time being days as effect of mechanical improvement in a few nations. Heavy metals and dyes give harmful consequences for human wellbeing and cause a few genuine maladies. A few systems have been utilizing for expelling toxic contaminants from the natural yet these strategies have impediments, for example, cost expense, logistical issues and time consuming, low efficiency. Phytoremediation is the best alternative for tidying up condition, as it is the naturally economical and ecologically practical innovation. Phytoremediation offers proprietors and chiefs of toxic polluted locales is an imaginative and financially effective choice to address headstrong natural contaminants. As it uses plants characteristic capacity to suck the contamination present in the dirt. There are numerous plants having this regular capacity to up take the toxic contaminants and natural contaminations from air, soil and water. There are distinctive subsets of phytoremediation; the most successfully utilized ones are (a) Phytostabilization (b) Rhizodegradation (c) Rhizofiltration (d) Phytodegradation (e) Phytoextraction (f) Phytoaccumulation (g) Phytovolatilization. This review focuses on fortifying innovation system, upgrade the resilience and protection from toxic contaminants, and application impact of phytoremediation.
149 citations
References
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TL;DR: The Biosphere The Anthroposphere Soils and Soil Processes Weathering Processes Pedogenic Processes Soil Constituents Trace Elements Minerals Organic Matter Organisms in Soils Trace Elements in Plants.
Abstract: Chapter 1 The Biosphere Chapter 2 The Anthroposphere Introduction Air Pollution Water Pollution Soil Plants Chapter 3 Soils and Soil Processes Introduction Weathering Processes Pedogenic Processes Chapter 4 Soil Constituents Introduction Trace Elements Minerals Organic Matter Organisms in Soils Chapter 5 Trace Elements in Plants Introduction Absorption Translocation Availability Essentiality and Deficiency Toxicity and Tolerance Speciation Interaction Chapter 6 Elements of Group 1 (Previously Group Ia) Introduction Lithium Rubidium Cesium Chapter 7 Elements of Group 2 (Previously Group IIa) Beryllium Strontium Barium Radium Chapter 8 Elements of Group 3 (Previously Group IIIb) Scandium Yttrium Lanthanides Actinides Chapter 9 Elements of Group 4 (Previously Group IVb) Titanium Zirconium Hafnium Chapter 10 Elements of Group 5 (Previously Group Vb) Vanadium Niobium Tantalum Chapter 11 Elements of Group 6 (Previously Group VIb) Chromium Molybdenum Tungsten Chapter 12 Elements of Group 7 (Previously Group VIIb) Manganese Technetium Rhenium Chapter 13 Elements of Group 8 (Previously Part of Group VIII) Iron Ruthenium Osmium Chapter 14 Elements of Group 9 (Previously Part of Group VIII) Cobalt Rhodium Iridium Chapter 15 Elements of Group 10 (Previously Part of Group VIII) Nickel Palladium Platinum Chapter 16 Elements of Group 11 (Previously Group Ib) Copper Silver Gold Chapter 17 Trace Elements of Group 12 (Previously of Group IIb) Zinc Cadmium Mercury Chapter 18 Elements of Group 13 (Previously Group IIIa) Boron Aluminum Gallium Indium Thallium Chapter 19 Elements of Group I4 (Previously Group IVa) Silicon Germanium Tin Lead Chapter 20 Elements of Group 15 (Previously Group Va) Arsenic Antimony Bismuth Chapter 21 Elements of Group 16 (Previously Group VIa) Selenium Tellurium Polonium Chapter 22 Elements of Group 17 (Previously Group VIIa) Fluorine Chlorine Bromine Iodine
9,739 citations
TL;DR: The generation, sites of production and role of ROS as messenger molecules as well as inducers of oxidative damage are described and the antioxidative defense mechanisms operating in the cells for scavenging of ROS overproduced under various stressful conditions of the environment are described.
Abstract: Reactive oxygen species (ROS) are produced as a normal product of plant cellular metabolism. Various environmental stresses lead to excessive production of ROS causing progressive oxidative damage and ultimately cell death. Despite their destructive activity, they are well-described second messengers in a variety of cellular processes, including conferment of tolerance to various environmental stresses. Whether ROS would serve as signaling molecules or could cause oxidative damage to the tissues depends on the delicate equilibrium between ROS production, and their scavenging. Efficient scavenging of ROS produced during various environmental stresses requires the action of several nonenzymatic as well as enzymatic antioxidants present in the tissues. In this paper, we describe the generation, sites of production and role of ROS as messenger molecules as well as inducers of oxidative damage. Further, the antioxidative defense mechanisms operating in the cells for scavenging of ROS overproduced under various stressful conditions of the environment have been discussed in detail.
4,012 citations
Additional excerpts
...[142,145], that remove the free radicals [146]....
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TL;DR: This review gives details about some heavy metals and their toxicity mechanisms, along with their health effects.
Abstract: Heavy metal toxicity has proven to be a major threat and there are several health risks associated with it. The toxic effects of these metals, even though they do not have any biological role, remain present in some or the other form harmful for the human body and its proper functioning. They sometimes act as a pseudo element of the body while at certain times they may even interfere with metabolic processes. Few metals, such as aluminium, can be removed through elimination activities, while some metals get accumulated in the body and food chain, exhibiting a chronic nature. Various public health measures have been undertaken to control, prevent and treat metal toxicity occurring at various levels, such as occupational exposure, accidents and environmental factors. Metal toxicity depends upon the absorbed dose, the route of exposure and duration of exposure, i.e. acute or chronic. This can lead to various disorders and can also result in excessive damage due to oxidative stress induced by free radical formation. This review gives details about some heavy metals and their toxicity mechanisms, along with their health effects.
3,580 citations
01 Jan 1980
TL;DR: In this paper, the essential roles of arsenic, fluorine, nickel, silicon, tin and vanadium have in recent years been established in animal nutrition, and they are known as trace elements, minor elements or micro-nutrients.
Abstract: Fifteen or more elements present in rocks and soils normally in very small amounts are essential for plant and/or animal nutrition. By the nature of their low abundance in natural uncontaminated earth materials or plants, they are known as trace elements, minor elements or micro-nutrients. Boron, copper, iron, manganese, molybdenum, silicon, vanadium and zinc are required by plants; copper, cobalt, iodine, iron, manganese, molybdenum, selenium and zinc by animals. In addition essential roles of arsenic, fluorine, nickel, silicon, tin and vanadium have in recent years been established in animal nutrition.
3,339 citations
"Microbial and Plant-Assisted Biorem..." refers background in this paper
...Toxic heavy metals such as lead (Pb), cadmium (Cd), mercury (Hg), chromium (Cr), zinc (Zn), uranium (Ur), selenium (Se), silver (Ag), gold (Au), nickel (Ni) and arsenic (As) which are not useful to plants, are capable of reducing plant growth due to reduced photosynthetic activities, plant mineral nutrition, and reduced activity of essential enzymes [1,2]....
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TL;DR: This review article comprehensively discusses the background, concepts and future trends in phytoremediation of heavy metals.
2,718 citations
"Microbial and Plant-Assisted Biorem..." refers background in this paper
...This deals with the removal of soil contaminants by plants which are readily changed into vapour and consequently released into the atmosphere [88,124]....
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...Phytoremediation deals with the cleanup of organic pollutants and heavy metal contaminants using plants and rhizospheric microorganisms [3,88,89]....
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...The degradation of organic pollutants in the soil could also be enhanced by rhizospheric microorganisms through the process of rhizodegradation [88,131,133,134]....
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...The functional groups of important molecules in the cell are hindered by metal toxicity and the normal functioning of enzymes and pigments in the disrupted biomolecules, which interferes with the structure of the cytoplasmic membrane [63,88,138], and consistently suppress photosynthesis, respiration and enzymatic activities [137–139]....
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...Phytodegradation is the breakdown of organic contaminants into non-hazardous forms by plant enzymes [88]....
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