Rajkumar Bidlan | Delhi Technological University, Delhi, India (original) (raw)
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Papers by Rajkumar Bidlan
Dichlorodiphenyltrichloroethane (DDT) is the first synthetic compound used against pests. Though ... more Dichlorodiphenyltrichloroethane (DDT) is the first synthetic compound used against pests. Though it was first synthesised by Zeidler, the noble prize for its activity against insects especially against body lice and in control of typhus fever was awarded to Dr. Paul Muller. After the discovery that DDT can be used against insects, it was extensively used by almost all the countries for both agriculture as well as health programs. Later, it was discovered that DDT was responsible for many environmental problems viz. thinning of the eggshells in many birds especially Falcons, bringing it under the endangered category, being one among the first few hazards noticed. Today it is one of the suspect culprits for hormonal imbalance and even cancer. Its main advantage, when initially used, was its effectiveness on wide variety of insects, leading to a large-scale application on pests. However, the persistency has been now the main cause of concern to the environmentalists. Residues of DDT ha...
The study involved testing the effects of mixture of Organochlorine pesticides (Lindane and DDT) ... more The study involved testing the effects of mixture of Organochlorine pesticides (Lindane and DDT) on the germination of seeds and simultaneous bioremediation of these pesticidesby a novel microbial consortium. These two pesticides (Lindane and DDT) were selected as they are Persistent Organic Pollutants (POP), widely used in the developing economies for agricultural usage and in particular DDT which is used for mass healthcare programs thereby contributing to environmental pollution. The study was done using green gram seeds which is one of the commonly consumed legumes in India. The seed growth in presence of these pesticides exhibited a noticeable reduction in vigour index that significantly reduced withincreasing concentrations of organochlorine mixture, Lindane and DDT, at 10 ppm, 20 ppm and 30 ppm concentrations. The germination of green gram seeds was repressed upto a viguor index of 21.1on moist filter paper at 30 ppm concentrations which was evident in reduction of amylase an...
Bioscience Biotechnology Research Communications, 2017
Journal of Pure and Applied Microbiology, 2017
Journal of Experimental Biology and Agricultural Sciences, 2018
Bioscience Biotechnology Research Communications, 2018
Bioscience Biotechnology Research Communications, 2019
International Journal of Pharmacy and Pharmaceutical Sciences, 2016
International Journal of Current Microbiology and Applied Sciences, 2016
Process Biochemistry, 2002
Microbial degradation of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT)-residues is one of t... more Microbial degradation of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT)-residues is one of the mechanisms for the removal of this compound from the environment. A DDT-degrading consortium was isolated by long term enrichment of soil samples collected from DDT-contaminated fields. This consortium was acclimated by repeated passages through a mineral salt medium containing increasing concentrations of DDT. This acclimated consortium could degrade 25 ppm of
International Journal of Environmental Science and Technology, 2019
Research Journal of Microbiology, 2007
Chemosphere, 2004
The effects of technical grade hexachlorocyclohexane (tech-HCH) on the germination of different s... more The effects of technical grade hexachlorocyclohexane (tech-HCH) on the germination of different seeds were tested. Two types of seeds, radish and green gram showed marked reduction in germination percentage and seeding vigour index. The abnormalities and reduction in germination increased with increasing concentration of tech-HCH. At 100 microg HCH level the germination of radish and green gram seeds was inhibited almost completely on moist filter paper and soil. Protease and amylase activities were reduced in seeds grown in soil spiked with tech-HCH. Bioremediation of HCH-spiked soils with a HCH-degrading microbial consortium helped in eliminating the toxic effects of tech-HCH towards seed germination. The degradation of 25 microg tech-HCH g(-1) soil was complete by 120 h. The seed germination and the activities of the assayed enzymes, amylase and protease, were same as before or better in bioremediated soils.
8 Abstract 9 The effects of technical grade hexachlorocyclohexane (tech-HCH) on the germination o... more 8 Abstract 9 The effects of technical grade hexachlorocyclohexane (tech-HCH) on the germination of different seeds were tested. 10 Two types of seeds, radish and green gram showed marked reduction in germination percentage and seeding vigour 11 index. The abnormalities and reduction in germination increased with increasing concentration of tech-HCH. At 100 lg 12 HCH level the germination of radish and green gram seeds was inhibited almost completely on moist filter paper and 13 soil. Protease and amylase activities were reduced in seeds grown in soil spiked with tech-HCH. Bioremediation of 14 HCH-spiked soils with a HCH-degrading microbial consortium helped in eliminating the toxic effects of tech-HCH 15 towards seed germination. The degradation of 25 lg tech-HCH g À1 soil was complete by 120 h. The seed germination 16 and the activities of the assayed enzymes, amylase and protease, were same as before or better in bioremediated soils. 17
Microbial degradation of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT)-residues is one of t... more Microbial degradation of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT)-residues is one of the mechanisms for the removal of this compound from the environment. A DDT-degrading consortium was isolated by long term enrichment of soil samples collected from DDT-contaminated fields. This consortium was acclimated by repeated passages through a mineral salt medium containing increasing concentrations of DDT. This acclimated consortium could degrade 25 ppm of DDT in 144 h. The consortium consisted of four bacteria. Of these, Serratia marcescens DT-1P was used for further studies. Various factors such as inoculum size, concentration of DDT, pH, temperature, presence of co-substrates, the type of carbon source used influenced the degradation of DDT in shake flasks. Complete degradation was observed up to 15 ppm DDT, followed by inhibitory effects at higher concentrations showing a total loss of degradative ability at 50 ppm DDT. Effective degradation of DDT was obtained with the inoculum pre-exposed to DDT for 72 h. Degradation was inhibited in the presence of auxiliary carbon sources such as citrate, rice straw hydrolysate. However, the presence of yeast extract, peptone, glycerol and tryptone soya broth (TSB) showed complete disappearance of DDT. Mesophilic temperatures (26 Á/30 8C) and near neutral pH (6.0 Á/8.0) were most favourable for degradation. This microbial culture holds the potential for use in bioremediation of DDT-contaminated soils, waste deposits and water bodies.
Dichlorodiphenyltrichloroethane (DDT) is the first synthetic compound used against pests. Though ... more Dichlorodiphenyltrichloroethane (DDT) is the first synthetic compound used against pests. Though it was first synthesised by Zeidler, the noble prize for its activity against insects especially against body lice and in control of typhus fever was awarded to Dr. Paul Muller. After the discovery that DDT can be used against insects, it was extensively used by almost all the countries for both agriculture as well as health programs. Later, it was discovered that DDT was responsible for many environmental problems viz. thinning of the eggshells in many birds especially Falcons, bringing it under the endangered category, being one among the first few hazards noticed. Today it is one of the suspect culprits for hormonal imbalance and even cancer. Its main advantage, when initially used, was its effectiveness on wide variety of insects, leading to a large-scale application on pests. However, the persistency has been now the main cause of concern to the environmentalists. Residues of DDT ha...
The study involved testing the effects of mixture of Organochlorine pesticides (Lindane and DDT) ... more The study involved testing the effects of mixture of Organochlorine pesticides (Lindane and DDT) on the germination of seeds and simultaneous bioremediation of these pesticidesby a novel microbial consortium. These two pesticides (Lindane and DDT) were selected as they are Persistent Organic Pollutants (POP), widely used in the developing economies for agricultural usage and in particular DDT which is used for mass healthcare programs thereby contributing to environmental pollution. The study was done using green gram seeds which is one of the commonly consumed legumes in India. The seed growth in presence of these pesticides exhibited a noticeable reduction in vigour index that significantly reduced withincreasing concentrations of organochlorine mixture, Lindane and DDT, at 10 ppm, 20 ppm and 30 ppm concentrations. The germination of green gram seeds was repressed upto a viguor index of 21.1on moist filter paper at 30 ppm concentrations which was evident in reduction of amylase an...
Bioscience Biotechnology Research Communications, 2017
Journal of Pure and Applied Microbiology, 2017
Journal of Experimental Biology and Agricultural Sciences, 2018
Bioscience Biotechnology Research Communications, 2018
Bioscience Biotechnology Research Communications, 2019
International Journal of Pharmacy and Pharmaceutical Sciences, 2016
International Journal of Current Microbiology and Applied Sciences, 2016
Process Biochemistry, 2002
Microbial degradation of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT)-residues is one of t... more Microbial degradation of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT)-residues is one of the mechanisms for the removal of this compound from the environment. A DDT-degrading consortium was isolated by long term enrichment of soil samples collected from DDT-contaminated fields. This consortium was acclimated by repeated passages through a mineral salt medium containing increasing concentrations of DDT. This acclimated consortium could degrade 25 ppm of
International Journal of Environmental Science and Technology, 2019
Research Journal of Microbiology, 2007
Chemosphere, 2004
The effects of technical grade hexachlorocyclohexane (tech-HCH) on the germination of different s... more The effects of technical grade hexachlorocyclohexane (tech-HCH) on the germination of different seeds were tested. Two types of seeds, radish and green gram showed marked reduction in germination percentage and seeding vigour index. The abnormalities and reduction in germination increased with increasing concentration of tech-HCH. At 100 microg HCH level the germination of radish and green gram seeds was inhibited almost completely on moist filter paper and soil. Protease and amylase activities were reduced in seeds grown in soil spiked with tech-HCH. Bioremediation of HCH-spiked soils with a HCH-degrading microbial consortium helped in eliminating the toxic effects of tech-HCH towards seed germination. The degradation of 25 microg tech-HCH g(-1) soil was complete by 120 h. The seed germination and the activities of the assayed enzymes, amylase and protease, were same as before or better in bioremediated soils.
8 Abstract 9 The effects of technical grade hexachlorocyclohexane (tech-HCH) on the germination o... more 8 Abstract 9 The effects of technical grade hexachlorocyclohexane (tech-HCH) on the germination of different seeds were tested. 10 Two types of seeds, radish and green gram showed marked reduction in germination percentage and seeding vigour 11 index. The abnormalities and reduction in germination increased with increasing concentration of tech-HCH. At 100 lg 12 HCH level the germination of radish and green gram seeds was inhibited almost completely on moist filter paper and 13 soil. Protease and amylase activities were reduced in seeds grown in soil spiked with tech-HCH. Bioremediation of 14 HCH-spiked soils with a HCH-degrading microbial consortium helped in eliminating the toxic effects of tech-HCH 15 towards seed germination. The degradation of 25 lg tech-HCH g À1 soil was complete by 120 h. The seed germination 16 and the activities of the assayed enzymes, amylase and protease, were same as before or better in bioremediated soils. 17
Microbial degradation of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT)-residues is one of t... more Microbial degradation of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT)-residues is one of the mechanisms for the removal of this compound from the environment. A DDT-degrading consortium was isolated by long term enrichment of soil samples collected from DDT-contaminated fields. This consortium was acclimated by repeated passages through a mineral salt medium containing increasing concentrations of DDT. This acclimated consortium could degrade 25 ppm of DDT in 144 h. The consortium consisted of four bacteria. Of these, Serratia marcescens DT-1P was used for further studies. Various factors such as inoculum size, concentration of DDT, pH, temperature, presence of co-substrates, the type of carbon source used influenced the degradation of DDT in shake flasks. Complete degradation was observed up to 15 ppm DDT, followed by inhibitory effects at higher concentrations showing a total loss of degradative ability at 50 ppm DDT. Effective degradation of DDT was obtained with the inoculum pre-exposed to DDT for 72 h. Degradation was inhibited in the presence of auxiliary carbon sources such as citrate, rice straw hydrolysate. However, the presence of yeast extract, peptone, glycerol and tryptone soya broth (TSB) showed complete disappearance of DDT. Mesophilic temperatures (26 Á/30 8C) and near neutral pH (6.0 Á/8.0) were most favourable for degradation. This microbial culture holds the potential for use in bioremediation of DDT-contaminated soils, waste deposits and water bodies.