جستجوی مقالات مرتبط با کلیدواژه « bioremediation » در نشریات گروه « محیط زیست »

In different regions of the Persian Gulf, oil pollution along with other urban, agricultural and industrial pollution has destroyed this valuable ecosystem and the valuable aquatic resources in it have been exposed to the risk of various corruptions and have threatened the aquatic populations in it. (Pourrang, 2005). The Caspian Sea is one of the unique lakes in the world due to its biological resources (plants and animals) and supply of protein materials, sturgeon fishing, and caviar production (Bazrafshan, 1374). In recent years, the increasing development of human activities in the countries bordering the Caspian Sea has changed the ecology of this sea. The Caspian Sea has oil and gas refineries and oil reserves in oil fields and exploration and drilling activities by five common countries, especially Azerbaijan and Kazakhstan. And the discharge of sewage and industrial effluents has caused the pollution of the sea (Varedi, 2015). Some microorganisms are present in the contaminated site, but for more effective remediation, the growth of the microorganism must be stimulated. Biostimulation is the process of adding nutrients, electron acceptors, and oxygen to stimulate bacteria in bioremediation. This is the process of optimizing the environmental conditions of the place of correction. Additives are usually added to subsurface layers through injection wells. Subsurface characteristics such as groundwater velocity, subsurface hydraulic conductivity, and subsurface lithology are essential for the development of a biological stimulation system. The natural microorganisms in the soil are responsible for the decomposition of pollutants. But biostimulation can be improved with biological additives. The quality of life on earth depends on the quality of the environment. Large amounts of organic and inorganic substances are released into the environment every year as a result of human activities. Contaminated lands are generally the result of industrial activities, the use, and disposal of hazardous substances, and such. It is now widely recognized that contaminated land is a potential threat to human health, and its continued discovery over the past 13 years has led to international efforts to remediate many sites, or as a response to health hazards.or environmental effects caused by pollution or to activate this place for use, to be developed again. Bioremediation is a general concept that includes all those processes and actions that take place to transform an environment, which is currently changedby pollutants to its original state (Adhikari, 2004; Gunasekaran, 2003). Also, bioremediation means the process of cleaning hazardous waste with microorganisms or plants, and it is the safest method of cleaning soil pollution.So far, there have been several studies on biological indicators (various plant and animal species as biological monitors) of heavy metals in both aquatic and terrestrial environments, which we can mention here. The use of biological information and biological control programs for water pollution for the management of ecosystems started at the beginning of the 1920s in the United States and then in a more serious way since 1948 all over the world. Today, many researchers from international organizations, including the EPA and the World Health Organization (WHO), introduced these indicators as the most appropriate indicators for environmental assessment and ecosystem management (Freund, 2007). Hilsenhoff's research, which started in 1979 with periodic sampling of the end of aquatic habitats and measurement of physical and chemical parameters, and finally using the biological coefficient formula; is considered a turning point in the biological evaluations of the environment (Hilsenhoff, 1988).Also, by examining the management of drilling waste, which is one of the new biological methods being developed in Iran, we will deal with it. The wastes of drilling operations are mainly the result of the washing and cooling activities of drilling machines. These wastes are generally divided into two groups in terms of physical phase: solids and liquids. In the new method invented in this collection, these wastes are managed separately. Solids are recycled by biological methods (composting) and liquids are recycled by three chemical methods, biological absorbents, and evaporation-condensation, depending on their initial quality. This new method first recycles water with the help of flow management and mixing, and then with different chemical, physical, and sometimes biological methods.The results of various surveys show that by measuring different pollutants in the plants of the same region, it is possible to understand the state of pollution of various compounds, including heavy metals (Lehndorff, 2009). In 2010, Bonanno and Gaddis in South Phragmites examined reed aquatic plants in terms of the accumulation of heavy metals cadmium, chromium, copper, mercury, manganese, nickel, lead, and zinc in the root, rhizome, stem and leaf tissues and concluded They found that the mentioned plant can be a monitor to control water pollution (Bonanno, 2010). Wild oysters can also be used to monitor pollution. In 2011, Victoria et al. investigated the concentration of heavy metals in the soft tissue of a species of wild oysters from the Spanish North Atlantic coast and stated that wild oysters are a benchmark for international evaluation. Besada, 2011). Also, in 2015, Phillips et al. tested the concentration of four heavy metals cadmium, copper, lead, and zinc in the tissue of three aquatic plants, and based on the results of the research they have conducted, these species are suitable for use as indicators of the presence and level of pollutants. Heavy metals are introduced into estuary water places (Phillips, 2015). In Iran, many types of research have been conducted so far, by examining their results, the potential of different species in the direction of bioremediation can be achieved, and we are now mentioning some of them. In 2013, during research, Azami et al. investigated the amount of total mercury in different tissues of three of the most important waterfowl species in the north of the country, including the great cormorant, the mallard, and the green duck, and compared the results with the international standard of the American Environmental Protection Organization. Global health and domestic standards are compared and finally, while warning consumers of waterfowl, especially vulnerable people, the results of their research are an achievement for managers to control and monitor metal pollution in Gamishan and Anzali wetlands, which are one of the most important habitats. The wintering birds are listed (Aazami, 2012).

Although bioremediation is not the answer to all pollution, it provides a method of removing pollution by enhancing biological processes and natural biological decomposition. Also, its application in each place must be determined and depends on the local mineralogy, hydrology, geology, and chemistry of that place. Therefore, with the development and understanding of microbial communities and their response to the natural environment and pollutants, expanding the knowledge of microbial genetics to increase the ability to reduce pollutants, and conducting proper tests of new bioremediation techniques that are cost-effective, this technology is an efficient and cost-effective way to purify water, contaminated land, and soil. Therefore, this method is being developed and improved to be able to cover more areas of pollution.

An alternative and environmentally friendly method for purifying the environment from pollution is the use of biosurfactant derived from microorganisms. The advantage of biosurfactant is biodegradability, low toxicity, and effectiveness in increasing biological decomposition. Unlike chemical surfactants, surface active substances produced by microbes are easily decomposed, and for this reason, they are very suitable for environmental applications, especially bioremediation. The aim of this study was bioremediation and investigation of the absorption kinetics of heavy metals and Rhodamine B from water by biosurfactant produced from Pseudomonas aeruginosa bacteria.

In this study, a biosurfactant-producing bacterium that was isolated and identified as Pseudomonas aeruginosa HAK02 from the Kahrizak waste site in the south of Tehran was used to produce a surface bioactive agent to remove pollutants. Zeta potential test was performed to detect the load of biosurfactant produced and used in bioremediation. The amount of color removal was done by UV device and the removal of heavy metals was done by ICP_AES analysis.

Due to the negative charge of the substance, it was used to remove heavy metals and Rhodamine B cationic dye. Biosurfactant produced with Pseudomonas aeruginosa was able to remove 95% rhodamine B, 43% Cd2+, and 35% Co2+. Examining the kinetic model of absorption showed that better correlation with pseudo-second order kinetic model.

Bioremediation using surfactants to remove heavy metals and dyeing is a fast and environmentally friendly method. This sample is very suitable for the removal of Rhodamine B and has the moderate ability for heavy metals Cd2+ and Co2+.

In the last few decades, contamination of the environment especially the soil by toxic metals has been increased extremely at worldwide. Entrance of toxic metals into the soil from various sources is a constant and serious threat to the health of plants, animals and human societies. Bioremediation by using of the beneficial soil microorganisms improves the remediation efficiency of the metal contaminated areas and is a suitable alternative method for substitution of current physico-chemical strategies.

Arbuscular mycorrhizal (AM) fungi are found in virtually all ecosystems worldwide, including in soil contaminated with toxic metals. AM fungi sequestrate toxic metals at fungal intra- and extracellular structures by different mechanisms, so in addition to reduce their toxic effects on host plant prevent from their entrance in the food chain. This study has been addressed the role of glomalin as an important molecule of the cell wall of AM fungi spores and hyphae in soils contaminated by toxic metals.

The results showed that glomalin as a specific product of AM fungi, is present in the role of a heat shock protein as well a critical and main component of spores and hyphal cell wall.

Glomalin plays an essential and key role in maintaining and improving the soil health by reducing toxicity and availability of metals for symbiotic partner of AM fungi and other organisms.

Natural and human activities lead to soil degradation and soil salinization. In the last two centuries, world metal pollution level has increased extremely. Presence of some heavy metals in aquatic ecosystems is a constant threat to the health of human societies. The decrease of farmlands threatens food security. There are approximately 1 billion ha salt-affected soils all over of world, which can be made available resources after chemical, physical and biological remediation. Existence of many mines in the world and also in Iran and as a result, soil erosion and dust release from waste dams is matter of concern. Bioremediation using biological agents to detoxify and degradation of environmental pollutants- provides a suitable alternative method for substitution of current heavy metals removal strategies.

Daily as a result of extraction operations by cyanidation in Mouteh gold mining complex, waste water and waste soil sediment widely achieved. In this study soil samples were collected from Mouteh Goldmine tailing damp soil in September 2018. The collected soil samples were cultured in BG11 medium and incubated for microalgae identification and biomass production. Also 5 gr soil inoculated with 0.5 gr biomass and the physico-chemical characteristics of the soil including pH, Na+ and K+, Pb and Cd, before and after the inoculation of soil with Cyanobacteria were determined.

in this study, cyanobacteria Phormidium tenue Gomont, Osillatoria tenuis C.Agardh ex Gomont, Lyngbya aestuarii Liebman ex Gomont and green Algae, Scenedesmus obliquus (Turpin) Kützing were identified. Culture results of filamentous cyanobacteria on goldmine tailing damp soil showed that cyanobacteria can grow easily and produced a surface crust significantly. The results of the Physical analysis of the soil samples showed that O. tenuis decreased Na as a salinity element, and P. tenue absorbed high amounts of Pb as a heavy metal pollution element. Probably by using Mouteh Goldmine soil cyanobacteria, Osillatoria tenuis and Phormidium tenue for mine tailingdamp soil bioremediation, could play mine recovery from salinity and heavy metals and also preventing soil erosion and dust release from waste dams.

Generally, it can be concluded thatdue to the existence of many goldmines in the word and Iran, daily as a result of extraction operations by cyanidation and high toxicity of cyanide, environmental adverse effects are observed. Dust release from waste dams can be affected health of living organisms like mining workers, plants and even soil microalgae which are close to the mine. By soil goldmine bioremediation can be processed biological resuscitation faster. The research results of African goldmine researchers on soil samples showed that cyanobacteria produced a surface crust significantly, that with the results of this research based on the growth of Phormidium tenue in the mine and producing a surface crust is consistent.

Petroleum hydrocarbon pollutants are one of the hardest compounds in terms of decomposition and control and classified as stable and important organic pollutants that have adverse effects on human health and the environment and combating environmental pollution caused by them is an important issue for the world and human societies. Although the removal of these pollutants from the environment is a major problem, biodegradation (which uses natural microbial biodegradation activity) is an ecofriendly and economical approach to control these types of contaminants and has become a pivotal method of cleaning up environments contaminated with petroleum hydrocarbons. The present study provides a comprehensive, uptodate and efficient review of the bioremediation of petroleum hydrocarbon pollutants, taking into account the hydrocarbon alterations in microorganisms with a particular focus on the new insights gained in recent years. Also, the metabolism of hydrocarbons in microorganisms has been described by reviewing research presented in recent years. The results of studies show well that petroleum hydrocarbon pollutants are biodegradable using some microorganisms such as oleophilic and their removal by this method is cost-effective and economical. Microbial biodegradation of petroleum hydrocarbon contaminants uses the enzymatic catalytic activities of microorganisms to increase the degradation of contaminants several times more than traditional methods

Bioremediation is an approach that exploits the ability of microorganisms to increase the rate and extent of degradation of pollutants and thereby removing pollutants from the environment. The moisture content and temperature are of the main environmental factors affecting growth and activity of microorganisms and accordingly affecting the efficiency of organic pollutant biodegradation.

To study the effect of these two factors a factorial experiment was carried out as completely randomized design with three replications. The factors were moisture in three levels (30%, 55% and 80% of Field Capacity), temperature in three levels (25, 30 and 35 degrees of Celsius) and inoculation with bacteria in two levels (with and without inoculation by Pseudomonas putida) which were triplicated.

The results showed that highest biodegradation rate was observed in the treatment with the moisture content of 55% F.C, temperature of 30 degrees of Celsius and inoculation with Pseudomonas putida which was 92.8% and the lowest biodegradation rate was observed in the treatment with the moisture of 30% F.C, temperature of 30 degrees of Celsius and without inoculation which was 42.3%.

These results shows that the optimization of the environmental conditions in bioremediation process may lead to 50.5% increase in the efficiency of removal.