The word “remediate” means to solve a problem, so the word “bioremediation” refers to the use of biological organisms to solve an environmental problem. Bacteria, fungi, protists and other microorganisms in a non-polluted environment are constantly breaking down organic matter, and when the soil is polluted, some of the organisms may die, but others will still be able to break down the pollutants. Bioremediation provides organisms that can consume the pollutants with fertilizer, oxygen, and other conditions to encourage the rapid growth of these organisms. They then would be able to break down the organic pollutants at a correspondingly faster rate. There are two general ways in which bioremediation functions. One way is where specific survival conditions of a microorganism living in the soil are enhanced to increase the rate of a pollutant’s degradation. The second way is when specialized microbes are added to degrade the contaminant. This way is less common. For many types of polluted soil, bioremediation provides an excellent method of clean-up, but in some cases the pollutant is toxic even for the microbes. These pollutants include metals such as cadmium or lead, and salts such as sodium chloride. Although it may not work in all cases, bioremediation is considerably easier than other methods because it enhances the functions that the microbes already carry out in the soil. Along with being easier, it can be much less expensive because the soil does not have to be pumped out of the ground for treatment (Environmental Inquiry-Bioremediation). Serratia Marcescens is a bacterium that is commonly used for bioremediation. The bacterium, Serratia marcescens, was first discovered by Bartholomeo Bizio in Padua, Italy in 1819. The bacte... ... middle of paper ... ...ppm of DDT. Effective degradation was achieved with an inoculum pre-exposed to DDT for 72 hours. In the presence of auxiliary carbon sources citrate and rice straw hydrolysate, the degradation was inhibited. In the presence of yeast extract, peptone, and glycerol and tryptone soya broth, there was a complete disappearance of DDT. The optimum conditions for degradation are mesophilic temperatures, (30-40 degrees Celsius) and a near neutral pH. (Science Direct-Aerobic Degradation of DDT by Serratia Marcescens). Using the new bacteria acclimated to DDT, fields where DDT was once applied can now be cleaned more thoroughly. The acclimated bacteria will still carry out their natural life functions, but now the metabolic processes of the Serratia Marcescens are now more capable of using the DDT as an energy source, and, therefore, the microbes will degrade the DDT faster.
Serratia marcescens, a Gram-negative bacillus, was originally and solely considered a biological marker in the medicinal industry, due to its highly natural red pigment: Prodigiosin (Hejazi and Falkiner, 1997). The pigment has numerous roles within bacteria, which can be further translated into the pharmaceutical and medical domain. This bacterium naturally occurs in water, soil, on plants as well as in humans and animals (Khanafari et al, 2006), where it is deemed an opportunistic pathogen.
Disinfection is applied in water as well as wastewater treatment as a finishing step so as to destroy pathogens but the cause of concern regarding the disinfection process is the formation of disinfection byproducts (DBPs). Natural organic matter (NOM) in water has been considered as the predominant DBP precursors. Disinfectants are powerful oxidants that oxidize the organic matter present in water forming DBPs. Chlorine, ozone, chlorine dioxide, and chloramines are the most common disinfectants used nowadays and each produces its own suite of chemical DBPs in finished drinking water (Richardson, 2003). DBPs so formed pose a threat to human health because of their potential to cause cancer and reproductive/developmental effects. Most developed nations have regulated concentration of DBPs so as to minimize exposure to potentially harmful DBPs while maintaining adequate disinfection and control of targeted
The process of identifying this microbe began by performing a Gram’s stain (see image #1, page 7). Pseudomonas fluorescens is a gram negative bacillus shaped bacterium. Following the establishment of the microorganism’s Gram stain
Peregrine Falcon status is special concern as this species was affected mainly by DDT (dichloro-diphenyl-trichloroethane) and PCBs (poly chlorinated biphenyls). DDT was used in 1950s and 1960s to control populations of insects. PCBs were previously used by industries. The adult Peregrine Falcon had high amount of DDT and PCBs by the process of bioaccumulation (when they eat more and more prey DDT was build up over time) and biomagnification (as falcon is the apex predator /top predator – The concentration of DDT progressively increases in food chains from bottom to top tropic level). Affected birds produced thin shell eggs that usually broke in the nest. This led the Falcons to produce lesser number of young birds than usual.
2) is the ratio between the uptake of the chemicals from food and their clearance. Bio-magnification is also called Bio-amplification. It is simply the increase in concentration of a substance in a food chain, not an organism (Sijm et al., 1992). Persistent organic pollutants (POPs) are compound that bio-magnify. Persistent organic pollutants (POPs) are chemical substances that persist in the environment. These substances bio-accumulate through the food web and pose risk not only to humans but also other living organisms because of their adverse effects. These pollutants consist of pesticides (such as DDT), industrial chemicals (such as polychlorinated biphenyls, PCBs) and unintentional by-products of industrial processes (such as dioxins and furans). In essence, bio-magnification is similar to bioaccumulation but is descriptive of higher level biological processes, not individual. DDT has a half-life of 15 years, which means if you use 100 kg of DDT; it will break down as
van den Berg, H 2009, ‘Global Status of DDT and Its Alternatives for Use in Vector Control to Prevent Disease’, Environmental Health Perspectives, vol. 117, no. 11, pp. 1656-1663, http://search.ebscohost.com.ezproxy.taylors.edu.my/login.aspx?direct=true&db=a9h&AN=47243502&site=eds-live, accessed 21 February 2012.
DDT has been proven to lower the number of malaria caused deaths. For example India’s malaria of 800 000 a year death rate was cut to zero by the late 1960s. In Sri Lanka DDT was reduced to 2.8 million cases a year to just 17. (Dyson, J) The US National Academy of Sciences in 1970 stated that DDT had prevented millions of deaths that would have been inevitable. Small amounts of DDT can affect small microorganisms. (Duke.edu) DDT microorganisms don’t usually die, they tend to keep the DDT in themselves this makes it bad for those predators who eat these organisms.
Although DDT has several harmful effects, it still can be used to effectively control the malaria. This chemical can kill mosquitoes that spread malaria. It helped eradicate the disease in southern Europe and North America in the 1960s. But DDT is also toxic to birds, fish and mammals. It accumulates in the food chain, and can exist for several years in the environment. After eating the plants that have been sprayed with DDT, the animals accumulate in the body for a long time. Since the 1970s, DDT has been banned globally and scientists have been able to detect DDT from many animals today. In 2001, the Stockholm Convention of United Nation Environmental program suggest to stop using the 12 chemicals include DDT.At the same time, there are signs of malaria in Africa because there is no suitable substitute.
The major impact of DDT is directed on the aquatic life, animals, and birds. The tendency of DDT to concentrate in fats, animals, and wildlife has the ability to detrimentally affect organisms. DDT was originally used to fight off a disease called malaria. It was a parasite contained by mosquitoes that spread from person to person. Sir Ronald Ross proved this disease and was awarded the Nobel Prize in Medicine for his discovery in 1902. DDT was widely used to control mosquitoes. It was easy to use and effective. To avoid mosquitoes, people sprayed DDT on the walls and ceiling of their houses and public buildings. It was also used by farmers who sprayed it on their crop fields using airplanes or helicopters. The long term effects of DDT started to arise. The population of animals, birds, and fishes started to decrease rapidly. By the 1950s, biologists started to believe DDT was a culprit. When certain toxic substances
The presence of radionuclides and heavy metals in our surroundings has become the most serious environmental concern. These contaminants or pollutants fail to degrade on their own over time and must be removed or neutralized. Microorganisms act as natural catalysts in the process of transformation of toxic metals into non-toxic ones. This is why there is an increased interest in the understanding of microbiological processes which help in remediation of these toxic wastes from the environment (Francis 1990).
Microbiology has helped preserve our food through different processes. By making sure our food doesn’t go bad very quickly that can also manage waste. More than 25% of food supply is wasted, however people die of hunger everyday. So by using microbial processes we can make
environmental concerns. According to Zhang et al (2017), DDT was the preferred pesticide because it is odourless, colourless, tasteless and is an effective pesticide in controlling the spread of
Pollution-eating bacteria are used to clean soil that is contaminated with petroleum wastes. Researchers have successfully developed a bacteria that reduces the complexity of oils and gasoline.
The term Bioremediation has been introduce to describe the process of removing of toxic waste from environment with the help of microorganisms. Bioremediation is most effective management technique to reduce the contamination of soil and recoveration of contaminated soil. Bioremediation is natural and successful cleaning technique for polluted environment.
1) Sampling of the soil and Field study – Type of area to be treated and bio monitoring of the field to decide whether bioremediation is possible mainly by pre-treatment assessment.