James F. Cuthbertson, P.E.,  Delta Environmental Consultants, Inc., 39810 Grand River Avenue, Suite C-100, Novi, Michigan, 48375, Tel: 248-699-0259, Fax: 248-699-0232, Email:  jcuthbertson@deltaenv.com
Lisa Noblet, Delta Environmental Consultants, Inc., 39810 Grand River Avenue, Suite C-100, Novi, Michigan, 48375, Tel: 248-699-0254, Fax: 248-699-0232, Email:  lnoblet@deltaenv.com
Lyle G. Bruce, PhD, BP Products North America Inc, Remediation Environmental Technology, 28100 Torch Parkway, Warrenville, Illinois 60555, Tel: 630-836-7174, Email:  lyle.bruce@bp.com 
Arati Kolhatkar, PhD, BP Products North America Inc. – Remediation Environmental Technology, 501 Westlake Blvd. , Suite 20.104B, Houston, TX  77079.  Tel: 281-366-5596, Email:  Arati.Kolhatkar@bp.com

Anaerobic degradation is the dominant driving force in natural attenuation of petroleum contamination in the subsurface. The contribution to natural attenuation by electron acceptors other than oxygen, such as nitrate, iron III, manganese IV, sulfate, and even carbon dioxide, has been the subject of considerable research in recent years.  The addition of these alternative electron acceptors has been shown to have many potential advantages over the traditional approach of attempting to add dissolved oxygen to the plume.  Kolhatkar et al. (2000), Wiedemeier et al. (1999), and Wilson et al. (2002) have shown that of these natural anaerobic processes, sulfate reduction accounts for most of the degradation.  Cuthbertson et al. (2006) presented case studies that demonstrated the benefits of using Magnesium Sulfate solution to stimulate the biodegradation of petroleum contaminants in groundwater under field conditions at various sites.  Results of detailed pilot studies performed at two sites in Michigan including changes in petroleum constituent concentrations, effects of application rates, determination of radius of influence, potential for aquifer clogging, influence of application solution concentrations and evaluation of potential adverse changes in soil gas composition will be presented.   The results of these pilot studies demonstrate the technical feasibility of utilizing sulfate solution to stimulate biodegradation to safely and expeditiously remediate petroleum impacted groundwater.  Updated results from case study sites presented in 2006 will also be discussed. 

Characterising and Testing a Novel Biological Reduction Cell to Remediate Heavy Metal and Acid-Containing Mineral Processing Leachates, Heybridge, Tasmania

Student Presenter

Alison L. Dann, University of Tasmania, Private Bag 54, School of Agricultural Science, Hobart, Tasmania 7001, Tel: +61 3 62262621, Fax: +61 3 62262642
John P. Bowman, University of Tasmania, Private Bag 54, School of Agricultural Science, Hobart, Tasmania 7001, Tel: +61 3 62262776, Fax: +61 3 62262642
Rodney Cooper, Echo Remediation PL, PO Box 402 Wynyard TAS 7325, Tel: +61 3 64424037, Fax: +61 3 64422588

At Heybridge a titanium processing plant operated between 1948 and 1996. The process used hydrochloric acid to extract the titanium from the ilmenite ore resulted in acidic metal-rich waste water being pumped into holding dams and left after the plant closed down. These dams leaked into the Blythe River catchment and ultimately Bass Strait . The leachates (pH 3.5 – 4.8) contained 620 – 1200ppm iron and other significant metals present included aluminium (93 – 320ppm), manganese (15 – 44ppm) and lead (18 – 160ppb) with low levels of cadmium, chromium, copper and zinc. These metals concentrations are 2 to 3 times higher than any acid mine drainage leachates in the published literature. The bioremediation system that was set up in 2001 utilises locally sourced agricultural waste products such as potatoes, mushroom compost and straw in enclosed bioreactors which promote the growth of sulfate- and metal-reducing bacteria. At present the system is running at 20 – 60% efficiency, hence an improved bioremediation system was required. To monitor the microbial diversity in the bioreactors a TRFLP (Terminal Restriction Fragment Length Polymorphism) method was used. TRFLP data correlated with 16S rRNA clone libraries constructed from the existing bioreactors. The clones sequenced were similar to iron- and sulfate-reducing and iron-oxidising Proteobacteria and Acidobacteria as well as Bacteroidetes and Firmicutes. Nearly half of the clones sequenced fell into lineages that are poorly represented by cultured organisms or have thus far been represented by only a few environmental sequences from contaminated aquifers. Laboratory-scale microcosms were set up to trial different amendments such as the addition of bicarbonate, ethanol, and molasses as well as heating and retention time to promote the growth of the metal-reducing and sulfate-reducing bacteria identified. This work will be followed by pilot-scale trials in small bioreactors on site leading to improvements to the full scale bioreactors.

Spill Cleanup of Fuel Contaminated Soils after Roadway Accidents Using In Situ Bioremediation

Satya Ganti, Sarva Bio Remed, LLC, 36 South Broad Street , Trenton, NJ 08608, Tel: 609-695-4922, Fax: 419-710-5831
Bob Frye, GEC Environmental Contracting Corp., 13880 Berlin Turnpike, Lovettsville, VA 20180, Tel: 540-882-3802, Fax: 540-882-3405

Release of fuel oils during transportation or during roadside accidents is very common. According to the figures available, number of incidents involving hazmat accidents has increased from 7,297 in 1990 to 14,443 in 1999.  In most cases the standard cleanup protocol is followed but in some cases it is not possible to follow the protocol because of the accident locations. It is particularly difficult to excavate surface soil where utility lines are very near to the surface. In such situations, it is considered safe to use effective bioremediation solution for on-site cleanup.  In these situations, AgroRemed has been employed with successful results.  Two case studies are presented in this paper, one study demonstrating revitalization of roadside vegetation through bioremediation after a spill of motor oil and in another case application of AgroRemed to sites affected by diesel spill with underlying utility cables.  The TPH of the soil after bioremediation was reduced by more than 95% from 65,000 ppm in the first case while in the second case, the TPH was found to be below the detectable values from the initial value of 47,000 ppm.  Both AgroRemed and VaporRemed are available in a ready to use liquid form and have been known to effectively bioremediate the contaminated soils and fumes in a very short period of time.  They de-toxify the contaminated soils and facilitate growth of vegetation.

Virginia Department Of Transportation (VDOT) was actively involved in the cleanup operations and although Virginia DEQ (VDEQ) was not directly involved, the department reviewed the data to confirm that the values of TPH were below the accepted levels.

Bioremediation of TOCs present in Fuel-contaminated Desert Mining Soil and Sawdust in the Atacama Region (Chile)  

Lorenzo Reyes Bozo, Department of Chemical Engineering and Bioprocesses, Pontificia Universidad Católica de Chile, Vic. Mackenna 4860, Macul, Santiago, Chile, and Centro de Investigación Minera y Metalúrgica, Ave Antonio Parque Rabat 6500, Vitacura, Santiago, Chile Tel: 562-354-7205, Fax: 562-54-5803, Email: lcreyes@ing.puc.cl
Dr Blanca Antizar-Ladislao, Dpto. de Ciencias y Técnicas del Agua y del Medio Ambiente, Universidad de Cantabria -Campus de Torrelavega, Bulevard Ronda Rufino Peón, 254 - Tanos 39316 Torrelavega – Cantabria, Spain, Tel: +34 942 846542, Fax: +34 942 846541, Email: antizarb@unican.es
Dr César Sáez Navarrete, Department of Chemical Engineering and Bioprocesses, Pontificia Universidad Católica de Chile, Vic. Mackenna 4860, Macul, Santiago, Chile, Tel: 562-354-4257, Fax: 562-354-5803, Email: csaez@ing.puc.cl
Alex Godoy-Faúndez, Universidad Andrés Bello, Ave República 220, Santiago Centro, Santiago, Chile, Tel: 562-661-8461, Email: agodoy@puc.cl

Continuous fuel spills in the Atacama region due to Chilean mining industry, and consecutive pollution abatement using sawdust as a low-cost locally available adsorbent material, have resulted in large amounts of fuel-contaminated material. The Chilean legislation treats this fuel-contaminated material as hazardous waste and therefore, it should be contained or treated. This research sought to investigate the application of in-vessel composting of a fuel-contaminated desert-mining soil and sawdust in the Atacama region (Chile) as a bioremediation treatment technology. The composting reactors were operated using five soil to sawdust ratios (S:SD, 1:0, 3:1, 1:1, 1:3, 0:1, on a dry weight basis) under mesophilic temperature (30- 40°C ), humidity (50% MC) and ventilation (16 L/min) over 56 days using laboratory-scale in-vessel composting reactors. Total organic carbon (TOC) concentration in the composting reactors was monitored according to the Standard Methods (USEPA SW 846). The highest (50%) and the lowest (35%) TOC removals were observed in the sawdust and soil reactors after 56 days of treatment, respectively. The proportion of sawdust, time of treatment and interaction between both parameters had a significant effect (p<0.050) on the TOC removal. Additionally, correlations between TOC removal, pH, TOC/N ratio and total N were encountered in the different treatments. In the abiotic controls, no TOC removal was observed, suggesting that TOC removal in the treated reactors was due to biodegradation mechanisms. Higher levels of sawdust corresponded with an incremental number of O.T.U. (T-RFLP) at the microbial communities. The results of this research indicate that bioremediation of an aged fuel-contaminated mixture of soil/sawdust is feasible in desert mining soils in the Atacama region. Nevertheless, this research also suggests the necessity of providing a correct balance of nutrients in order to optimize the bioremediation treatment towards a maximum TOC removal.

Bioluminescence Bioassays by Testing Whole Solid and their Solid-aqueous Extracts from Various Sites in Korea

In C. Kong, Dept. of Environ. Eng. , Yeungnam University , Kyungbuk 712-749, Korea , Tel: +82-53-810-2546, Fax: +82-53-810-4624, Email: ickong@ynu.ac.kr
H. Jung, Dept. of Environ. Eng. , Yeungnam University , Kyungbuk 712-749, Korea ,  Tel: +82-53-810-3785, Fax: +82-53-810-4624, Email: jjjjblue84@nate.com
Kyung S. Ko, Korea Institute of Geoscience & Mineral Resources, Daejon, Korea,  Tel: +82-42-868-3162, Fax: +82-42-861-9723, Email: kyungsok@kigam.re.kr

Ecosystems are mostly exposed to complex mixtures made up of various pollutants, different chemical forms (chemical species), metabolites, or pollutants in complexes with non chemical stressors. Release of some chemicals into the ecosystem causes concern because of their toxic effects at very low concentration. Chemical data alone, therefore, are not sufficient to evaluate the toxic effects of the contaminants and characterize contaminated environment, because they are not able to provide information on the effects of the chemical compounds and do not take into consideration the interactions between contaminants, matrix and biota. And only a limited number of compounds can be analyzed by chemical analysis. One major advantage of biological toxicity tests, over chemical analysis, is direct assessment of the potential hazard to the soil ecosystem caused by the mixture contaminants. The aim of this present study was to demonstrate a rapid bioluminescence bioassay to determine toxicity of complex mixtures in various solid samples collected from Korea .  

Developed method was applied on whole and extracted solid samples. Test results with extracted samples showed lower toxicity and more variation than those with direct test. No significant correlation was observed between two test results. Such results may be due to the effects of complexity of the interactions of various contaminants with solid components, according to soil characteristics, such as pH, organic contents, redox potential, and contaminants properties. Though the solid-direct ecotoxicity tests indicated more harmful effect of the contaminated soil than the tests using soil extracts, the high variable toxicity by the soil extracts may be well related with the extractable portion of pollutant concentration in samples. According to these results it is highly recommended to complement the direct toxicity testing with soil extract toxicity testing to characterize the risks of contaminated soil. Future aim is to develop a practical interpretation for the relationship between contaminants by chemical analyses and both toxicity results.

Comparison of In-Situ Groundwater Bioremediation Technologies at a Dry Cleaner Release Site

Joseph P. Kraycik, P.G., MA, BA.  Environmental Standards, Inc.  1140 Valley Forge Road, P.O. Box 810, Valley Forge, PA 19482-0810, Tel: 610-935-5577, Fax: 610-935-5583, E-mail: jkraycik@envstd.com
Gerald L. Kirkpatrick, P.G., MS, BS.  Environmental Standards, Inc.  1140 Valley Forge Road, P.O. Box 810, Valley Forge, PA 19482-0810, Tel: 610-935-5577, Fax: 610-935-5583, E-mail: gkirkpatrick@envstd.com

Two pilot-scale in-situ engineered bioremediation technology and monitoring programs were conducted at a project site located in north-central Pennsylvania to compare the potential effectiveness of patented groundwater treatment technologies to address dissolved-phase volatile organic compounds (VOCs) in groundwater.  Groundwater and soil at the site are impacted with chlorinated ethenes resulting from an historic dry cleaner release. 

Initially, after formula injection of the first substrate, groundwater monitoring results were favorable and indicated that chlorinated VOC degradation was beginning to occur.  As time progressed, however, data clearly indicated that the in-situ microbial VOC breakdown that had been initiated was no longer occurring.

Evaluation of the groundwater monitoring results from the first groundwater treatment technology led to the conclusion that its failure was the result of a combination of the following factors:

Groundwater pH was severely affected by the production of acids post-injection and the acids inherently part of the substrate causing aquifer microbes to negatively respond through reduced reductive dechlorination activity. The relatively high viscosity of the substrate at the time of injection contributed to an uneven distribution of the injection material into the aquifer.  The dehalococcoides bacterial population present in the aquifer was somewhat low relative to what could be described as an “optimal” population count.

Based on the results of the first program, a modified in-situ treatment and monitoring program that included a focused application of a second commercially available substrate into the subsurface was initiated.  The second substrate injection program also included the introduction of sodium bicarbonate as a buffering agent to better manage the reduced groundwater pH levels.

Evaluation of analytical results and field-measured bioremediation parameters from the second, modified treatment suggested that a site-wide groundwater remediation strategy utilizing the alternative substrate is more appropriate at this particular site. 

Bioremediation of Arsenic Using Arsenite-Oxidizing Bacteria

Suranjit K. Prasad, Ph.D. Scholar, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India , 110067, Tel: 01191-9891276656
Jaishree Paul, Scientist B, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India, 110067, Tel:01191-9868047466
V. Subramanian, Prof. Biogeochemistry, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India, 110067, Tel: 01191-9810000878

Millions of people in the Eastern parts of India and Bangladesh suffer from arsenic toxicity because of natural contamination of drinking water by arsenic. The present research work addresses this problem by developing and testing a microbial intervention technology. Toxicity of arsenic is differential as far as species of arsenic is concerned i.e. arsenite As³⁺ toxicity is approximately 100 times higher than its pentavalent form (arsenate As⁵⁺). Chemical compound like Al₂O₃, Fe(OH)₃, activated charcoal etc have been tested for removal of arsenic but they can effectively adsorb only arsenate while most of the arsenite remain dissolved in drinking water. Thus over all question of elimination of arsenic from potable water remain questionable. Living cell prokaryotic as well as eukaryotic have different resistance mechanism to counter the toxicity of arsenic. In prokaryotes three kinds of enzymes responsible for detoxification of arsenic has been reported e.g. cytoplasmic arsenate reductase, respiratory arsenate reductase and very less described arsenite oxidase. We conceptualize to harsen the As(III) binding property of large subunit of enzyme arsenite oxidase coupled with chemical like alumina or activated charcoal to filter out arsenic from contaminated water.  At first we designed nucleotide primer form the most conserved region of the large subunit of an enzyme arsenite oxidase. After screening several bacterium grew in minimal media, with this sets of primer, we have been able to isolate a bacterium harboring partial gene sequence accession no.(AM 492534) of large subunit of enzyme arsenite oxidase. We report here a bacterium, Arthrobacter 15b accession no.(AM 491801)  capable of oxidizing arsenite to arsenate when cultivated in a medium containing 7.5 mM NaAsO₂. The bacterium was identified using molecular phylogenetic analysis. The enzyme responsible for the oxidation process was characterized biochemically. The presence of this enzyme prompted us to look for the arsenite oxidizing gene (aoxA and aoxB) . We present here our findings in this direction.

Feather Wastes as Petroleum Sorbents: Study of its Structural Biodegradation

Norma G. Rojas-Avelizapa, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada - IPN. Cerro Blanco 141, Colinas del Cimatario, Querétaro, Qro. México 76090. Tel: 52+5557296000 Ext. 81031, Fax: 52+4422290769  Email: nrojasa@ipn.mx
Elsa Cervantes-González, Depto. de Microbiología, Escuela Nacional de Ciencias Biológicas, Casco de Sto. Tomas Mexico City, México 11340, Tel: 52+5553412343, Fax: 52+53412343, Email: elcege@hotmail.com
Luz I. Rojas-Avelizapa, L.I., Depto. de Microbiología, Escuela Nacional de Ciencias Biológicas Casco de Sto. Tomas  Mexico City, México 11340, Tel: 52+ 55 53412343,Fax: 52+53412343, Email: luziremx@yahoo.com.mx
Ramón Cruz-Camarillo, Depto. de Microbiología, Escuela Nacional de Ciencias Biológicas Casco de Sto. Tomas Mexico City, México 11340 Tel: 52+ 55 53412343,Fax: 52+55 53412343, Email: cruzcamarillo@hotmail.com
Jaime García-Mena, Depto. de Genética y Biología Molecular, CINVESTAV-Zacatenco Av. IPN 2508, Mexico City. Mexico 07360, Tel. 52+ 55 5061-3800 Ext. 5328, Fax: 52+ 55 5061-3392, Email: jgmena@cinhtvestav.mx

In México, it is common to find hydrocarbon-contaminated sites in areas of difficult access such as marshes and mangles. This problem has encouraged the use of sorbents for hydrocarbon spills, being the most used synthetic sorbents of low cost and high effectiveness. However the disposal of these materials is complicated due to the cost related to their confinement and incineration which cause even more contamination and promotes climate changes. The use of biodegradable sorbents for hydrocarbon removal is an “earth-friendly” attractive alternative. Chicken feathers (CF) are a suitable option because in addition to its high affinity for petroleum, the waste resulting can be degraded by keratinolytic microorganisms. The present report evaluates by scanning electron microscopy (SEM), the biodegradation of CF occurring when they were used in combination with a defined-mixed culture with abilities to remove hydrocarbons and produce keratinases in liquid culture (unpublished results). Treatments were carried out in Erlenmeyer flasks, containing 25 ml of mineral media, 6% w/v of CF and petroleum hydrocarbons (64,800 mg/l). Flasks were inoculated with the keratinolytic-mixed culture and incubated at 28ºC , 180 rpm during 21 days. Every 7th day, samples were analyzed by SEM and the residual hydrocarbons were extracted and quantified by gas chromatography. Controls without inoculum were processing at the same conditions. The micrographs show the different stages of CF biodegradation; at initial time, CF are complete and the microorganisms from the mixed culture only are in the supernatants. After 7 day of treatment, the biodegradation of CF begins as well as the colonization of feathers. Since the day 14 was very considerable the biodegradation and the adhesion of the microorganisms on the CF. We conclude that feathers are excellent support for hydrocarbon contamination removal due to their dual function as support, sorbent and their concerted biodegradation by the same microorganisms.

Enhanced Bioremediation Pilot Study of a Cr (VI)-Impacted Overburden Groundwater System in Kanpur, Uttar Pradesh, India

I. Richard Schaffner, Jr., P.G., C.G.W.P., GZA GeoEnvironmental, Inc, 380 Harvey Road, Manchester, NH 03103, Tel: 603-623-3600, Fax: 603-624-9463, Email: rschaffner@gza.com
Rajiv Kumar Singh, Ph.D., Central Pollution Control Board, M/o Envt.& Forests; Govt.of India, PIC-UP Building (GF),Gomtinagar, Lucknow-10, Uttar Pradesh, India, Tel: 91-522-2721915, Fax: 91-522-2721891, Email: rsingh1962@rediffmail.com, rksingh.cpcb@nic.in
Steven R. Lamb, P.G., C.G.W.P., GZA GeoEnvironmental, Inc, 380 Harvey Road, Manchester, NH 03103, Tel: 207-879-9190, Fax: 207-879-0099, Email: slamb@gza.com
Donald N. Kirkland, P.E., GZA GeoEnvironmental, Inc, 380 Harvey Road, Manchester, NH 03103 , Tel: 603-623-3600, Fax: 603-624-9463, Email: dkirkland@gza.com

Pilot-scale electron donor injection enhances hexavalent chromium Cr (VI) biochemical reduction to Cr (III) in an overburden groundwater system impacted by Cr (VI) disposal in Kanpur , Uttar Pradesh , India .  The Study Area is located in the Indo-Gangetic alluvial plain, and is characterized by overburden stratigraphy consisting of up to about 50 meters of generally fine to medium sand interbedded with silty clay, which is underlain by about 100 meters of laterally continuous clay.  The clay is underlain by interbedded fine to medium sand and clay to a depth of about 500 meters, which overlies granitic bedrock.  Cr(VI) has been detected for about 20 years at concentration up to 16 milligrams per liter in groundwater samples collected from the shallower fine to medium sand unit.  The source is believed to be indiscriminate dumping of wastes resulting from production of Basic Chrome Sulfate [Cr(OH)₂SO₄] and other reagents used by local leather tanneries.  Approximately 540 kilograms of a carbohydrate-based remedial additive were injected into two wells screened in the fine to medium sand unit using about 40,000 liters of groundwater.  Treatment solution make-up water was obtained from a downgradient extraction well located within the Cr (VI) plume, amended with remedial additive, and then injected into the upgradient wells to establish hydraulic control on the injection and to minimize dilution.  Performance monitoring included five rounds of groundwater sampling for Cr (VI), total chromium, and certain indicator parameters, including total organic carbon (TOC) as an electron donor surrogate.  Pilot study results suggest that remedial additive amendment resulted in an up to 99.9% reduction in Cr (VI) concentration; an up to 97% reduction in total Cr; and up to an order of magnitude increase in TOC concentration over the four month study.

Use of Denitrifying Bioretention Systems to Control Non-Point Sources of Nitrogen

Student Presenter

Ryan Siegel, Dept. Civil & Environmental Engineering, University of Massachusetts, 18 Marston Hall, Amherst, MA 01003, Tel: 413-427-5535, Fax: 413-545-2202
Sarina J. Ergas, Dept. Civil & Environmental Engineering, University of Massachusetts, 18 Marston Hall, Amherst MA 01003, Tel: 413-545-3424, Fax: 413-545-2202
Sukalyan Sengupta, Dept. Civil & Environmental Engineering, University of Massachusetts Dartmouth, 285 Old Westport Rd., North Dartmouth MA 02747, Tel: 508-999-8470, Fax: 508-999-8964

Non-point sources of ammonia, organic N, nitrate and nitrite cause eutrophication in freshwater and marine ecosystems.  Eutrophication degrades water quality due to algae growth and depletion of aquatic life.  Public health is another concern with high nitrate or nitrite levels in drinking water, since these compounds are known to cause methaemoglobinaemia in infants.  Control of point sources of nitrogen, such as discharges from municipal wastewater treatment plants, has been a focus of environmental agencies over the last few decades.  However, control of non-point nitrogen sources, such as atmospheric deposition, leaking septic systems and runoff from fertilizer use and animal wastes has been inadequate.  This research focuses on the use of bioretention systems to control non-point sources of nitrogen.  Two pilot-scale bioretention systems were designed and constructed with an aerobic nitrification layer and an anoxic denitrification layer.  The anoxic denitrification layer differed in the two systems in that one was composed of a wood chip media to support the growth of heterotrophic denitrifiers and the other was composed of an elemental sulfur/oyster shell media and supported the growth of autotrophic sulfur oxidizing denitrifiers.  The units were tested in the laboratory under varying total nitrogen (organic N, ammonia and nitrate) and co-contaminant (e.g. suspended solids, phosphorus, metals) loading rates and transient conditions typical of stormwater treatment units.  Once the units are optimized they will be field tested at an agricultural site in Connecticut.  The results of this study will be presented at the meeting.     

Aerobic Degradation of 3-Nitrophenol by Pseudomonas aeruginosa Strain 3-NP-1 Isolated From Sewage Treatment Plant

Student Presenter

Deepak Singh, Department of Chemistry, Indian Institute of Technology , Kanpur, India-208016, Tel: +91-512-2597417, Fax: 91-512-2597436, Email: singhds@iitk.ac.in, deepak_226@yahoo.co.in
Leela Iyengar, Department of Chemistry, Indian Institute of Technology, Kanpur, India- 208016, Tel: +91-512-2597104, Email: leela @iitk.ac.in
Gurunath Ramnathan, Department of Chemistry, Indian Institute of Technology, Kanpur, India- 208016, Tel: +91-512-2597417, Email: gurunath@iitk.ac.in

Nitrophenols are widely used in the manufacture of explosives, pharmaceuticals, pesticides, pigments, dyes and wood preservatives. Thus they will be present in the industrial effluents and have the potential to contaminate surface/ground water. Due to their high solubility and xenobiotic character, removal of nitrophenols requires specialized bacterial strains. Reports on the degradation of 3-nitrophenol (3-NP) are scarce. The present study reports the isolation and characterization of a bacterial strain degrading 3-NP.

3-NP degrading strain was isolated by serial enrichment from the sludge of a sewage treatment plant situated at Jajmau, Kanpur city. The strain was identified to be Pseudomonas aeruginosa by using biochemical tests as well as 16S rDNA sequence analysis. This strain was able to utilize 50mg/L 3-NP in the minimal medium devoid of any other carbon and nitrogen source. With ammonium chloride and 10mg/L yeast extract, degradation was observed up to 100mg/L 3-NP .However when succinate (1 mM) was used, the strain could tolerate and degrade even  200 mg/L 3-NP efficiently. No intermediate could be detected during growth phase.  Release of ammonia (56%) and absence of nitrite in the culture broth during degradation indicate that 3-NP degradation was proceeding through reductive pathway. Total organic carbon (TOC) analysis of culture filtrate at the end of exponential growth phase indicated the extensive mineralization of 3-NP.Resting cell preparations could degrade repeated additions of 3-nitrophenol (100mg/L) even up to six cycles. Further studies are underway.  

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