Home About us MoEF Contact us Sitemap Tamil Website  
About Envis
Whats New
Microorganisms
Research on Microbes
Database
Bibliography
Publications
Library
E-Resources
Microbiology Experts
Events
Online Submission
Access Statistics

Site Visitors

blog tracking


 
Abstracts of Recent Publications
Abstracts 1 2 3 4 5 6 7 8 9 10 11 12



001- Sirpa Metsrinne a, Erja Ronkainen a, Tuula Tuhkanen b, Reijo Aksela c, Mika Sillanp (a University of Kuopio, Department of Environmental Sciences, P.O. Box 1627, FI-70211 Kuopio, Finland). Biodegradation of novel amino acid derivatives suitable for complexing agents in pulp bleaching applications. Science of the Total Environment, 377 (2007), 45-51.

The biodegradability of four novel diethanolamine derivative complexing agents was examined by using two biodegradation tests standardised by OECD (301B and 301F). Ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) were employed as reference substances. Biodegradation of the new complexing agents was studied both with unacclimated and acclimated inocula as well as by simulating wastewater treatment in sequencing batch reactors (SBRs). These new complexing agents were of technical grade, and therefore, the results are only indicative but these new compounds hold promise for use as complexing agents in the pulp and paper industry. The novel complexing agents were not readily biodegradable but they showed slight biodegradation. Around 10-30% degradation was found in the SBR where degradation was followed by measurement of concentration. Moreover the novel complexing agents did not have any negative impact on reactor performance as measured by chemical oxygen demand reduction. In the standardised biodegradation tests at best around 50% degradation was observed with the acclimated inoculum and in the prolonged test whereas EDTA and DTPA exhibited no biodegradation. The elevated degradation in acclimated sludge indicates that the water treatment plant microbes are capable of decomposing these molecules under favourable conditions. The total concentration of novel complexing agents decreased slightly during biodegradation tests, while the EDTA and DTPA concentrations remained stable.

Keywords: Biodegradation test; Complexing agents; Diethanolamine derivatives; DTPA; EDTA; Sequencing batch reactor.


UP
002-Gtz Haferburg a, Martin Reinicke a, Dirk Merten b, Georg Bchel b, Erika Kothe (a. Friedrich-Schiller-University, Institute of Microbiology, Microbial Phytopathology, Neugasse 25, 07743 Jena, Germany). Microbes adapted to acid mine drainage as source for strains active in retention of aluminum or uranium. Journal of Geochemical Exploration, 92 (2007). 196-204.

The use of microorganisms for the extraction of contaminants like solved metals from drainage or surface waters was investigated using strains adapted to a polluted environment at a former uranium mining site near Kauern, Eastern Thuringia, Germany. Soil respiration data showed increasing variation indicating stress response and hence need for adaptation.

Thus, isolation of single strains was performed for more detailed analyses. Of the isolated fungi and bacteria (single-celled bacteria as well as filamentous actinobacteria), 15 were grown in mine drainage waters in order to test their capacity to retain (heavy) metals including rare earth elements and radioisotopes. Out of the 15 strains (respectively 5 single-celled bacteria, actinobacteria and fungi), 11 strains could grow in media containing acid mine drainage waters diluted by half which is representative of the conditions a few meters downstream of the entry point of the acid mine drainage. Two strains showed promising capacity for aluminum or uranium retention. Using rare earth elements as tracers, selective biosorption or uptake of heavy rare earth elements was prominent in one sample, a fungal isolate. The actinobacterial strains also showed capacity for bioremediation of contaminated seepage waters. Different reactions to single elements varying between all isolates indicate biologically controlled transport processes because such strong fractionation would not be expected from physico-chemical adsorption processes.

Keywords: Heavy metals; Rare earth elements; Retention; Bioremediation; Bacteria; Fungi.

UP


003- Susan H. Ferguson a, Shane M. Powell b, Ian Snape a, John A.E. Gibson c, Peter D. Franzmann d. (a Department of the Environment and Heritage, Australian Government Antarctic Division, Kingston, 7050, Australia b University of Tasmania, Hobart 7001, Tasmania, Australia c CSIRO Marine Research, GPO Box 1538, Hobart 7001, Tasmania, Australia d CSIRO Land and Water, Underwood Ave, Floreat 6014, Western Australia, Australia). Effect of temperature on the microbial ecology of a hydrocarboncontaminated Antarctic soil: Implications for high temperature remediation. Cold Regions Science and Technology, 2007.

A series of nutrient-amended microcosms was used to investigate changing microbial communities during biodegradation in hydrocarbon-contaminated Antarctic soils at 4, 10 and 42 C. Although sample heterogeneity resulted in no statistically significant reduction in total petroleum hydrocarbons, biodegradation ratios indicate significant mineralisation. The number of culturable bacterial grown at 4 and 10 C increased from 3105 g-1 dry soil then peaked after 5 days incubation at 5107 g-1 dry soil, before decreasing to and remaining stable at ca. 2107 g-1 dry soil. While the bacterial population grown at 42 C was initially a minor constituent of the total culturable bacterial population, after 40 days there was similar numbers of bacteria estimated at all temperatures investigated. Denaturing gradient gel electrophoresis indicated significant differences in the microbial community between the 4 and 10 C and the 42 C microcosms.

Numerically dominant culturable hydrocarbon degrading bacteria were isolated at each temperature; 16S rRNA gene sequences identified the 4 and 10 C isolates as Pseudomonas spp., and the 42 C isolates as Paenibacillus spp. Fatty acid methyl ester profiles of the cultures were consistent with these identifications. The results from this study indicate that bioremediation treatments will substantially after the soil microbial ecosystem. All isolates form this study were capable of growth at 28 oC. The presence of autochthonous hydrocarbon degrading microbes capable of growth at higher temperatures introduces the possibility of in situ remediation treatment options involving heating (ca. 10-28 oC) to accelerate the rate of hydrocarbon degradation.

Keywords: Biodegradation; Microcosms; Petroleum contamination; Paenibacillus spp.; Pseudomonas spp. DGGE.
UP



004-Sangjin Lee. (Research and Development Center, Korea Coast Guard, 3-8 Bunji, Songdo-Dong, Yunsu-Gu, Incheon 406-130, South Korea). Enhanced dissolution of TCE in NAPL by TCEdegrading bacteria in wetland soils. Journal of Hazardous Materials, 145 (2007), 17-22.

The influence of trichloroethene (TCE) dechlorinating mixed cultures in dissolution of TCE in nonaqueous phase liquid (NAPL) via biodegradation was observed. Experiments were conducted in batch reactor system with and without marsh soils under 10 and 20 ?C for 2 months. The dissolution phenomenon in biotic reactors containing mixed cultures was showed temporal increases compared to abiotic reactors treated with biocide. Effective NAPL-water transfer rate (Km) calculated in this study showed more than four times higher in biotic reactors than that in abiotic reactors. The results might be attributed to the biologically enhanced dissolution process via dechlorination in reactors. Temperature would be a factor to determine the dissolution rate by controlling bacterial activity. The TCE dechlorination occurred even in an interface of TCE-NAPL that demonstrated no previous TCE biodegradation, suggesting that microbes may be useful in developing source-zone bioremediation system. In conclusion, dechlorinating mixed culture could enhance dissolution in NAPL that may be useful in the application of source zone bioremediation.

Keywords: TCE; Dechlorination; Biodegradation; NAPL (nonaqueous phase liquid); Dissolution.

Up


005-Elizabeth Boddya, Paul W. Hillb, John Farrarb, David L. Jonesa, (a School of the Environment and Natural Resources, University of Wales, Bangor, Gwynedd LL57 2UW, UK bSchool of Biological Sciences, University of Wales, Bangor, Gwynedd LL57 2UW, UK). Fast turnover of low molecular weight components of the dissolved organic carbon pool of temperate grassland field soils. Soil Biology & Biochemistry, 39 (2007), 827-835.

Large amounts of low molecular weight (LMW;o250 Da) carbon (C) are lost from roots into the rhizosphere as a consequence of root turnover and exudation. Their rates of turnover after release into the soil remain poorly understood. We extracted soil solution from a temperate grassland Eutric Cambisol, isotopically labeled the glucose and amino acid components, and then re-injected the solution back into the soil. We followed the subsequent evolution of 14CO2 and incorporation of the LMW C into the soil microbial biomass or grasses for 48 h. The experiments were performed both on grazed and ungrazed swards in the field, and in the laboratory. In the field, we showed that glucose and amino acids had short half-lives (t1/2) in soil solution (t1/2 20-40 min), but that they persisted in soil microbes for much longer. A first-order double exponential model fitted the experimental data well and gave rate constant (k) values of 1.21-2.14 h_1 for k1 and 0.0025-0.0048 h_1 for k2. Only small amounts of the added 14C were recovered in plant biomass (o5% of total added to soil) indicating that plant roots are poor competitors for LMW dissolved organic C (DOC) in comparison to soil microorganisms. The first phase of glucose and amino acid mineralization in the laboratory was slower (t1/2 40-60 min) than measured in the field reinforcing the importance of making flux measurements in situ. Whilst grazing stimulated below-ground respiration, it exerted only a small influence on the turnover of LMW DOC suggesting that the increase in respiration was due to increased root respiration and not turnover of soil organic matter (SOM). Our results suggest that some components of the LMW DOC pool are turned over extremely rapidly (ca. 4000 times annually).

Keywords: Biodegradation; Carbon cycling; Carbon dioxide; Dissolved organic carbon; Dissolved organic nitrogen; DOC; DON; Grazing; Mineralization; Rhizodeposition; Soluble carbon.

UP


006-Roly Oliver a, Eric May b, John Williams a. (a Department of Civil Engineering, University of Portsmouth, Lion Gate Building, Lion Terrace, Portsmouth, Hants, PO1 3HF United Kingdom b School of Biological Sciences, University of Portsmouth, King Henry Building, King Henry 1 Street, Portsmouth, Hants, PO1 2DY United Kingdom). Microcosm investigations of phthalate behaviour in sewage treatment biofilms. Science of the Total Environment, 372 (2007), 605-614.

Discharge from sewage works has been shown to be an important source of phthalates into the environment which is of major concern because some are toxic, suspected endocrine disruptors and recalcitrant. Laboratory trickle filter microcosms (continuous and recirculating flow) were constructed and operated to investigate the biodegradation and adsorption of phthalates and also to isolate phthalate degrading microorganisms. It was found that adsorption was critical for the removal of both DEP (77.5%) and DEHP (55.7%) in continuous flow microcosms. The proportion of phthalates removed by biodegradation in the continuous flow microcosms was estimated. Recirculating flow microcosms improved the removal of DEHP compared to continuous flow microcosms. Microcosm biofilm used for an enrichment culture on phthalate media isolated a varied group of microbes including Gram negative and Gram positive bacteria, yeasts and fungi. Bacteria species with all the necessary enzymes to degrade phthalic acid were isolated.

Keywords: Phthalate; DEHP; DEP; Microorganisms; Sewage; Microcosms.

UP


007-James P. Amona, Abinash Agrawalb, Michael L. Shelleyc, Bryan C. Oppermanc, Michael P. Enrighta, Nathan D. Clemmerc, Thomas Slusserb, Jason Lachb, Teresa Sobolewskic, William Grunera, Andrew C. Entinghc. (a Wright State University, Department of Biological Sciences, Dayton, OH 45435, United States b Wright State University, Department of Earth & Environmental Sciences, Dayton, OH 45435, United States c Air Force Institute of Technology, Department of Systems & Engineering Management, Graduate School of Engineering, 2950 Hobson Way, Wright- Patterson Air Force Base, OH 45433, United States). Development of a wetland constructed for the treatment of groundwater contaminated by chlorinated ethenes. Ecological engineering, 3 0 (2 0 0 7), 51-66.

An upward-flowing subsurface supply wetland designed to mimic natural wetland systems shows evidence of sequential dechlorination of PCE in contaminated groundwater. An inherent microzonation in the rhizosphere of plants that extend roots over 1m into the soil apparently sustains communities of microbes responsible for both anaerobic and aerobic activity. PCE dechlorination and production of methane near the bottom of the soil column suggest that anaerobic or reducing conditions exist there, but core samples indicate roots may create oxygen-enriched zones throughout the depth of the wetland. Methane is available to stimulate oxidative cometabolism via methane monooxygenases and those enzymes may be responsible for removal of trichloroethene (TCE) microzones where higher levels of oxygen is supplied by abundant roots. Samples taken during different seasons show elevated degradation during the warmer months but mid-winter samples show significant removal of PCE and its breakdown products. Herbaceous plants derived from local wetland species grew well and did not appear to be visibly harmed by the PCE or its by-products.

Core sampling of the root system indicates that more roots are found when a mixture of wetland plant species are planted. Benchscale experiments with 14C labeled TCE show that wetland plants can also play a role in bioremediation by venting volatiles to the atmosphere. We suggest that minor modifications such as increased organic matter in the soil may lead to more rapid establishment of wetland performance.

Keywords: Perchloroethene;Phytoremediation;Bioremediation Groundwater; Rhizosphere.

UP


008-Bart Lievens a,b, Loes Claes b, Matthew S. Krause b, Alfons C.R.C. Vanachter b, Bruno P.A. Cammue a, Bart P.H.J. Thomma c . (a Centre of Microbial and Plant Genetics (CMPG), Katholieke Universiteit Leuven, Kasteelpark Arenberg 20, B-3001 Heverlee- Leuven, Belgium b Scientia Terrae Research Institute, Fortsesteenweg 30A, B-2860 Sint-Katelijne-Waver, Belgium c Laboratory of Phytopathology, Wageningen University, Binnenhaven 5, 6709 PD Wageningen, The Netherlands). Assessing populations of a disease suppressive microorganism and a plant pathogen using DNA arrays. Plant Science, 172 (2007), 505-514.

Understanding the relationships between disease suppressive microbial populations and plant pathogens is essential to develop procedures for effective and consistent disease control. Currently, DNA array technology is the most suitable technique to simultaneously detect multiple microorganisms. Although this technology has been successfully applied for diagnostic purposes, its utility to assess different microbial populations, as a basis for further study of population dynamics and their potential interactions, has not yet been investigated. In this study, a DNA macroarray with multiple levels of phylogenetic specificity was developed to measure population densities of a specific disease suppressive microorganism, Trichoderma hamatum isolate 382, and the plant pathogen Rhizoctonia solani. Amongst others, the DNA array contained genus-, species- and isolate-specific detector oligonucleotides and was optimized for sensitive detection and reliable quantification of the target organisms in potting mix samples. Furthermore, this DNA array was used to quantify disease severity as well as incidence of severe disease based on pathogen population densities in the growing medium. Taking into account the unlimited expanding possibilities of DNA arrays to include detector oligonucleotides for other and more microorganisms, this technique has the potential for studying the population dynamics and ecology of several target populations in a single assay.

Keywords: Biological control; Disease management; Integrated pest management (IPM); Multiplex; Reverse dot blot; Quantification.

UP


009-Jong-Shik Kima, Gerd Sparovekb, Regina M. Longoc, Wanderley Jose De Meloc,David Crowleya,. (a Department of Environmental Sciences, University of California, Riverside, CA, USA bDepartment of Soil Science, ESALQ, University of Sao Paulo, Piracicaba CP 9, CEP 13418-900, Brazil cDepartment of Technology, Universidade Estadual Paulista, Jaboticabal, SP, CEP 14884-900, Brazil). Bacterial diversity of terra preta and pristine forest soil from the Western Amazon. Soil Biology & Biochemistry, 39 (2007), 684-690.

The survey presented here describes the bacterial diversity and community structures of a pristine forest soil and an anthropogenic terra preta from the Western Amazon forest using molecular methods to identify the predominant phylogenetic groups. Bacterial community similarities and species diversity in the two soils were compared using oligonucleotide fingerprint grouping of 16S rRNA gene sequences for 1500 clones (OFRG) and by DNA sequencing. The results showed that both soils had similar bacterial community compositions over a range of phylogenetic distances, among which Acidobacteria were predominant, but that terra preta supported approximately 25% greater species richness. The survey provides the first detailed analysis of the composition and structure of bacterial communities from terra preta anthrosols using noncultured-based molecular methods.

Keywords: Bacterial diversity; Forest soils; Microbial ecology; Terra preta.

UP


010-Brandon Clark, Raj Boopathy. (Department of Biological Sciences, Nicholls State University, Thibodaux, LA 70310, USA). Evaluation of bioremediation methods for the treatment of soil contaminated with explosives in Louisiana Army Ammunition Plant, Minden, Louisiana. Journal of Hazardous Materials, 143 (2007), 643-648.

Two bioremediation methods, namely, soil slurry reactor and land farming technique were evaluated for the treatment of soil contaminated with explosives in Louisiana Army Ammunition Plant, Minden, Louisiana. The soil had a high concentration of 2,4,6- trinitrotoluene (TNT) of 10,000 mg/kg of soil and medium level contamination of RDX 1900 mg/kg andHMX900 mg/kg of soil. The results indicated that soil slurry reactor under co-metabolic condition with molasses as co-substrate removed TNT more efficiently than land farming method. TNT removal efficiency was 99% in soil slurry reactor compared to 82% in land farming after 182 days. HMX and RDX were also removed from the soil in both methods, but the removal efficiency was low. The radiolabeled study showed that soil microbes mineralize TNT. The mass-balance of TNT indicated 23.5% of TNT was mineralized to CO2, 22.6% was converted to biomass, and 52.3% was converted to various TNT intermediates in the soil slurry reactor. Both methods maintained high bacterial population fairly well. The results of this bench-scale study are promising with regard to transferring the technology to full-scale application at this site.

Keywords: TNT; Soil slurry; Land farming; Bioremediation; Cometabolism; Co-substrate.

UP


011-Carey K. Bagdassariana, Amy E. Dunhamb,1, Christopher G. Browna,2, Daniel Rauschera,2. (a Department of Chemistry, College of William and Mary, P.O. Box 8795, Williamsburg, VA 23187-8795, USA bDepartment of Organismic and Evolutionary Biology, Harvard University, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, MA 02138, USA). Biodiversity maintenance in food webs with regulatory environmental feedbacks. Journal of Theoretical Biology, 245 (2007), 705-714.

Although the food web is one of the most fundamental and oldest concepts in ecology, elucidating the strategies and structures by which natural communities of species persist remains a challenge to empirical and theoretical ecologists. We show that simple regulatory feedbacks between autotrophs and their environment when embedded within complex and realistic food-web models enhance biodiversity. The food webs are generated through the niche-model algorithm and coupled with predator-prey dynamics, with and without environmental feedbacks at the autotroph level. With high probability, especially at lower, more realistic connectance levels, regulatory environmental feedbacks result in fewer species extinctions, that is, in increased species persistence. These same feedback couplings, however, also sensitize food webs to environmental stresses leading to abrupt collapses in biodiversity with increased forcing. Feedback interactions between species and their material environments anchor food-web persistence, adding another dimension to biodiversity conservation. We suggest that the regulatory features of two natural systems, deep-sea tubeworms with their microbial consortia and a soil ecosystem manifesting adaptive homeostatic changes, can be embedded within niche-model food-web dynamics.

Keywords: Environmental feedbacks; Food webs; Predator-prey dynamics; Niche model; Species persistence.

UP


012-Susan H. Ferguson a, Shane M. Powell b, Ian Snape a, John A.E. Gibson c, Peter D. Franzmann d (a Department of the Environment and Heritage, Australian Government Antarctic Division, Kingston, 7050, Australia b University of Tasmania, Hobart 7001, Tasmania, Australia c CSIRO Marine Research, GPO Box 1538, Hobart 7001, Tasmania, Australia d CSIRO Land and Water, Underwood Ave, Floreat 6014, Western Australia, Australia). Effect of temperature on the microbial ecology of a hydrocarboncontaminated Antarctic soil: Implications for high temperature remediation. Cold Regions Science and Technology , (2007).

A series of nutrient-amended microcosms was used to investigate changing microbial communities during biodegradation in hydrocarboncontaminated Antarctic soils at 4, 10 and 42 C. Although sample heterogeneity resulted in no statistically significant reduction in total petroleum hydrocarbons, biodegradation ratios indicate significant mineralisation. The number of culturable bacterial grown at 4 and 10 C increased from 3105 g- 1 dry soil then peaked after 5 days incubation at 5107 g- 1 dry soil, before decreasing to and remaining stable at ca. 2107 g- 1 dry soil. While the bacterial population grown at 42 C was initially a minor constituent of the total culturable bacterial population, after 40 days there was similar numbers of bacteria estimated at all temperatures investigated. Denaturing gradient gel electrophoresis indicated significant differences in the microbial community between the 4 and 10 C and the 42 C microcosms. Numerically dominant culturable hydrocarbon degrading bacteria were isolated at each temperature; 16S rRNA gene sequences identified the 4 and 10 C isolates as Pseudomonas spp., and the 42 C isolates as Paenibacillus spp. Fatty acid methyl ester profiles of the cultures were consistent with these identifications. The results from this study indicate that bioremediation treatments will substantially alter soil microbial ecosystem. All isolates from this study were capable of growth at 28 C. The presence of autochthonous hydrocarbon degrading microbes capable of growth at higher temperatures introduces the possibility of in situ remediation treatment options involving heating (ca. 10-28oC) to accelerate the rate of hydrocarbon degradation.

Keywords: Biodegradation; Microcosms; Petroleum contamination; Paenibacillus spp.; Pseudomonas spp. DGGE.

UP


ENVIS CENTRE Newsletter Vol.5, July 2007 Back 
 
     
Copyright © 2005 ENVIS Centre ! All rights reserved
This site is optimized for 1024 x 768 screen resolution