Bioremediation of pesticides in surface soil treatment unit using microbial consortia

The manufacturing and use of pesticides has been rising tremendously in India. The waste generated by the pesticide industry has become an environmental problem due to the present insufficient and ineffective waste treatment technology involving physico-chemical and biological treatment. The available data indicates that pesticide residues remain in surface soil, leading to toxicity in the soilwater environment. The recent advances in bioremediation technology using microbial consortium has been found effective for treatment of pesticides in soil. In the present study, a Surface Soil Treatment Unit has been designed wherein bioremediation of commonly used pesticides namely chlorpyrifos, cypermethrin, fenvalerate, and trichlopyr butoxyethyl ester at varying concentration viz. 25, 50 and 100 mg/kg have been carried out using cow-dung microbial consortia under simulated environmental conditions. The bioremediation conditions have been monitored and maintained during the study. The investigation has been extended till the parent compound was converted into intermediates and/or less harmful compounds. These then will further mineralize, from part of the microbial food chain and/or become integrated into the humic fractions. The results presented here highlight the potential of cowdung slurry consortia for bioremediation of soil contaminated with pesticides in surface soil treatment unit.Key words: Bioremediation, surface soil treatment unit, pesticides, cow-dung, microbial consortia

Remediation of anthracene in mycorrhizospheric soil using ryegrass

Rhizosphere bioremediation has become an effective technique that uses green plants to enhance biodegradation of persistent organic pollutants such as polycyclic aromatic hydrocarbons (PAHs), pesticides and radionuclides. Polycyclic aromatic hydrocarbons, due to their hydrophobic nature were found to be retained in the soil. Plants could be grown at the PAH contaminated sites to stimulate the biodegradation in the rhizosphere. In the present study, biodegradation of anthracene was studied using ryegrass in mycorrhizosphere soil by laboratory scale pot culture experiments. Ryegrass (Lolium multiflorum) was grown in pots containing soil contaminated with various levels of anthracene. Soil and plants from treated pots were sampled after 15, 30, 45 and 60 days and compared with uncontaminated planted pots. In the mycorrhizosphere, the concentrations of anthracene in the soil were found to be 5.2, 7.88, 15.43, 33.23 and 41.5 mg/kg at the 15 days harvest which further decreased to 0.31, 0.45, 0.89, 1.89 and 2.43 mg/kg over a period of 60 days when exposed to the initial concentrations of 10, 25, 50, 75 and 100 mg/kg amended in soil, respectively. Plant shoot and root dry biomass were observed to be significantly reduced at higher anthracene concentrations (75 and 100 mg/kg) whereas low concentrations had no distinct effect on plant biomass (p<0.05). The increase in the microbial counts was also monitored and quantified along the degradation of the anthracene in the soil. The findings of this research show that there is rapid degradation of anthracene under the influence of ryegrass mycorrhizosphere.Key words: Rhizosphere bioremediation, Lolium multiflorum, arbuscular mycorrhizal fungi, PAHs

HIGH-PERFORMANCE THIN LAYER CHROMATOGRAPHY (HPTLC) FINGERPRINTING PATTERN OF MANGROVE AVICENNIA MARINA

Objective: An attempt has been made to study phytoconstituents and High-Performance Thin Layer Chromatography (HPTLC) fingerprinting pattern of leaf/stem/root methanol extracts of Avicennia marina.Methods: The phytochemical screening was done by standard biochemical methods and standard optimized HPTLC densitometry determination was performed under two different energy zones [under UV-254 nm and under 540 nm after derivatization at sample size-10 µl, temperature = 25.8±0.3 °C (constant) and relative humidity = 86±1% (constant) in optimized solvent system].Results: Phytochemical analysis confirmed the presence of phytochemicals in the leaf, stem, and root of the plant. Under UV–254 nm energy range, the leaf, stem and root extract showed the presence of 8, 6 and 5 components respectively and under 540 nm energy zone after derivatization, the leaf, stem and root extract revealed the presence of 7, 5 and 5 components, respectively and specific marker components with very high concentration (under UV-254 nm; 3, 2, 2 in leaf, stem, and root respectively and under 540 nm after ASR treatment; 2, 1, 2 in leaf, stem, and root respectively) were detected among them.Conclusion: The preliminary phytochemical test results elucidated Avicennia marina leaf, stem, and root as a hug reservoir of various class of phytochemicals and metabolites. The results obtained by HPTLC fingerprinting method found to be acceptable as a quick, reliable, accurate and economical for identification and authentication of Avicennia marina mangrove plant and useful to differentiate this mangrove species from other similar mangroves, in a single TLC plate run. This serves as a biochemical marker pattern for leaf, stem and root parts of this mangrove and for its diverse phytoconstituents

Investigation of potential rhizospheric isolate for cypermethrin degradation

Rhizoremediation is the use of plant–microbe interaction for the enhanced degradation of contaminants. Rhizosphere bioremediation of pyrethroid pesticides will offer an attractive and potentially inexpensive approach for remediation of contaminated soil. The present study was done with the aim of establishment of highly effective remediation method using plant with degradative rhizosphere and isolation of naturally occurring rhizosphere associated potential degrader providing the possibility of both environmental and insitu detoxification of cypermethrin contamination. The remediation efficacy of Pennisetum pedicellatum was investigated using green house pot culture experiments in cypermethrin amended potting soil mix (10, 25, 50, 75 and 100 mg/kg) for periodic evaluation of changes in concentration. Total proportion of cypermethrin degraders was found to be higher in rhizosphere soil compared to bulk soil. The cypermethrin degrading strain associated with rhizosphere capable of surviving at higher concentrations of cypermethrin was designated as potential degrader. On the basis of morphological characteristics, biochemical tests and 16S rDNA analysis, isolate was identified as Stenotrophomonas maltophilia MHF ENV 22. Bioremediation data of cypermethrin by strain MHF ENV22 examined by HPLC and mass spectroscopy, indicated 100, 50 and 58 % degradation within the time period of 72, 24 and 192 h at concentrations 25, 50 and 100 mg/kg, respectively. This is the first report of effective degradation of cypermethrin by Stenotrophomonas spp. isolated from rhizosphere of Pennisetum pedicellatum. Rhizoremediation strategy will be of immense importance in remediation of cypermethrin residues to a level permissible for technogenic and natural environment

Microbial degradation of petrochemical waste-polycyclic aromatic hydrocarbons

Abstract Background Petrochemical industry is one of the fastest growing industries. This industry has immense importance in the growth of economy and manufacture of large varieties of chemicals. The petrochemical industry is a hazardous group of industry generating hazardous waste containing organic and inorganic compounds. In spite of the present treatment process, the hazardous waste compounds are found untreated to the acceptable level and found discharged at soil–water environment resulting into the persistent organic–inorganic pollutant into the environment. The bioremediation will be the innovative techniques to remove the persistent pollutants in the environment. Result Petrochemical contaminated site was found to be a rich source of microbial consortium degrading polycyclic aromatic hydrocarbons. Indigenous microbial consortiums were identified and used for bioremediation of polycyclic aromatic hydrocarbons (naphthalene and anthracene) at the concentrations of 250, 500, and 750 ppm. The potential microorganism was also identified for naphthalene and anthracene, and their bioremediation was studied at varying concentrations. The bioremediation with consortium was found to be comparatively more effective than the potential microorganism used for bioremediation of each compound. Pseudomonas aeruginosa a potential organism was identified by 16S rRNA and further studied for the gene responsible for the PAH compounds. Conclusion Indigenous microorganism as a consortium has been found effective and efficient source for remediation of organic compound—Polycyclic aromatic hydrocarbon and this will also be applicable to remediate the toxic compounds to clean up the environment

Phytoremediation of heavy metals: Recent techniques

The current remediation technique of heavy metal from contaminated soil-water are expensive, time consuming and environmentally destructive. Unlike organic compounds, metals cannot degrade, andtherefore effective cleanup requires their immobilization to reduce or remove toxicity. In recent years, scientists and engineers have started to generate cost effective technologies that include use ofmicroorganisms/biomass or live plants to clean polluted areas. Phytoremediation is an emerging technology for cleaning up contaminated sites, which is cost effective, and has aesthetic advantages and long term applicability. It is best applied at sites with shallow contamination of organic, nutrient or metal pollutants that are amenable to one of the five applications; phytotransformation, rhizosphere bioremediation, phytostabilization, phytoextraction and rhizofiltration. The technology involves efficient use of plants to remove, detoxify or immobilize environmental contaminants in a growth matrix (soil, water or sediments) through the natural, biological, chemical or physical activities or processes of the plants. A brief review on phytoremediation of heavy metals and its effect on plants have been compiled to provide a wide applicability of phytoremediation

Vermicomposting of vegetable waste: A biophysicochemical process based on hydro-operating bioreactor

The increasing waste generation rate, high collection cost and dwindling financial resources are the major problems faced by most of the developing countries for efficient solid waste management. Insome cities, the organic waste (market, municipal, household) are dumped indiscriminately or littered on the streets causing environmental deterioration. Biological processes such as composting followed by vermicomposting to convert vegetables waste (as valuable nutrient source) in agriculturally useful organic fertilizer would be of great benefit. Therefore this technique is studied in the present research work. A simple and potentially inexpensive Hydro Based Operating Bioreactor (HBOB) was developed for aeration and turning of plant biomass for efficient aerobic composting process. The compostingprocess was done viz ambient, mesophilic, thermophilic and cooling down stages for a period of two weeks. After cooling stage, the partially decomposed material was used further as bedding forearthworms for vermicomposting. Experiments were conducted to determine the changes in the physicochemical parameters (pH, temperature, moisture content and C/N ratio). The dominant speciesof microorganisms at different temperatures during entire process of composting and vermicomposting were investigated. Self heating of the ingredients due to microbial activity occurred within thebioreactor at the thermophilic stage of the composting process. The vermicompost developed in the HBOB was found to have comparatively high value of nutrients such as calcium, sodium, magnesium,iron, zinc, manganese and copper which can serve as a natural fertilizer giving high yield of plants. The vermicomposting has proved very effective and efficient for developing compost from vegetable waste