This is post no. 11 under the main topic.
| 08-18-2013, 05:14 AM
Use of biological organisms, such as bacteria, fungi (usually) and plants (sometimes), to reduce or eliminate toxic pollutants from contaminated sites by degradation, assimilation or transpiration in the atmosphere is called bioremediation. Degradation is the mode of elimination mostly in case of organic compounds, while heavy metals are assimilated.
1. Microbial bioremediation
Bioremediation of organic compounds is primarily based on either microorganisms naturally present at the sites, or on microbial inoculants developed in the laboratory and introduced at the site. Certain bacterial, fungal and algal species are capable of accumulating some toxic inorganic contaminants as well. However, there is no cost-effective method of removing these microorganisms from the soil after they have sequestered the inorganic ions. Therefore, bioremediation of inorganic contaminants is primarily based on suitable plant species.
E.g. oil spills are known to cause fire, ground water pollution due to percolation, death of marine life and air pollution on evaporation. Earlier saw dust was used to treat oil spills. However, with the advent of bioremediation techniques, oil-eating bacteria have been used to treat the oil spills in a much more efficient and cost effective way.
E.g. Pseudomonas sp
Phytoremediation is the use of green plants and their associated microorganisms, soil amendments. And agronomic practices to remove contain or render harmless environmental contaminants. Plants were first used in Germany for sewage treatment over 300 years ago and since then their use has become rather common. Plants are also used to decontaminate soils polluted by organic wastes. For example, carrots are used to absorb DDT; these carrots are harvested, air dried and incinerated to destroy the DDT.
Plant roots absorb organic compounds and perform remediation by accumulating the organics in plant tissues, translocation to leaf and then volatilization or by metabolizing and degrading the organic compounds intrinsically using enzymes.
Plants remove inorganic contaminants wither by contaminant volatilization or by metal accumulation. Volatilization is a useful process for recovering mercury however the latter method is preferred for other inorganic compounds. The plants used in bioremediation have to be appropriately disposed.
E.g. A. thaliana converts volatile Hg to Hg (O)
This is post no. 12 under the main topic.
| 08-27-2014, 04:22 PM
(This post was last modified: 08-27-2014, 04:26 PM by Administrator.)
Thanks for sharing such an interesting and informative post. I want to add few more lines in that Bioremediation does not solely depend on microorganisms. Bioremediation is the process of utilizing biological means to eliminate toxic wastes from the environment. Phytoremediation is a bioremediation involving plants. Bioremediation can be carried out using live, dead or resting cells of microorganisms. Contaminated soil recovery and management of polluted environment can be successfully handled by bioremediation process.
Since, bioremediation is a flourishing and effective cleaning mechanism for polluted environment it is in use in many places around the world with varying degree of success. This results in strong scientific growth of the process.
Bioremediation is based on two major techniques: biodegradation and biosorption i.e. either the pollutant is degraded to a less polluting substance so that it can enter easily into the biogeochemical cycle or it is absorbed within the body of the biological substances used. So it is clear that biodegradation is metabolism dependent, whereas biosorption is independent of metabolism of the cells involved.
Bioremediation came up as a solution for several environmental pollution issues like landfill stabilization, endocrine disrupters, mixed waste biotreatment and biological carbon sequestration specially using aerobic and anaerobic bacteria and fungi.
Bioremediation has capacity to detoxify effluents and solid wastes at low cost with less impact on the environment. No doubt it is coming up as an attractive alternative to conventional cleaning techniques. Though the method is not very complex, still it needs enough knowledge and experience to successfully set up a bioremediation plant.
Proper use can make bioremediation a economically favorable treatment for cleaning certain oil-contaminated environments. But there are certain constraints. Spilled oil cannot be treated in open environment using Bioaugmentation where the addition of nutrients gives similar results. But in confined spaces Bioaugmentation works better. Addition of nutrients along with bioremediation can be a potent alternative in handling oil-contaminated coasts. This process can be used both as a primary as well as secondary (after conventional method) strategy to counter oil-spill, depending on the nature and location of the spill i.e. whether to be cleaned immediately or not. Efficiency of biostimulation is also highly site-specific and depends on the factors like availability of oxygen and nutrients. The process works better when oxygen is not a limiting factor. In anaerobic situations addition of nutrients often has very less impact on oil biodegradation. The choice of nutrients is also important and depends on the nature of oil spills.
Nevertheless bioremediation possess a bright future in cleaning our environment and thus demand thrust and more energy as well as investments for future studies and successful scientific implementation of the process.
This is post no. 15 under the main topic.
| 04-17-2015, 04:58 AM
(This post was last modified: 04-17-2015, 05:35 AM by Administrator.
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Do you have idea on difference between bioremediation and biodegradation with examples