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Revista de la ciencia del suelo y nutrición vegetal

versión On-line ISSN 0718-2791

R.C. Suelo Nutr. Veg. v.8 n.especial Temuco  2008

http://dx.doi.org/10.4067/S0718-27912008000400020 

 

J. Soil Sci. Plant Nutr. v8 no especial 2008 (142-145)

ORAL ABSTRACTS

                                                     

Session 5. Environmental Biotechnology: Biochemical and Molecular Mechanisms of Microbe-Plant-Root Interactions & Their Genomic & Proteomic Advances Pertaining to Restoration of Contaminated Soils

 

Geomicrobiology of Acidic Hot Spring from the Largest Geothermal Region, Kamojang, West Java, Indonesia

A. Akhmaloka*. H. Yohandini, P. Aditiawati and F. Madayanti

Biochemistry Research Division, Faculty of Mathematics and Natural Sciences, Instituí Teknologi Bandung, Jin Ganesha 10, Bandung, Indonesia. * E-mail: loka@chem.itb .ac.id

Keywords: Acidic hot spring; thermophilic microorganisms; DGGE

Kamojang is one of the biggest geothermal regions in Indonesia. This area has a few hot springs divided into two types eg geyser and poll mad hot springs. Two hot springs, namely Kawah Hujan A (KHA) and Kawah Hujan B (KHB) represented both type of hot spring were chosen as model for assaying the biodiversity of thermophilic microorganism. The physico-chemical of the hot springs was differences. The KHA has pH at around 7.2 - 7.4, temperature at 80-86° C with concentration of Fe and sulfate ion at 0.08 and 156 mg mL-1 respectively, while KHB has pH 1.8-1.9, temperature at 90-92° C and Fe and sulfate ion at 12 and 2,740 mg/mL respectively. Biodiversity of thermophilic microorganism from these hot springs were analysis using 16 SrRNA gene sequences combining with DGGE method. The biodiversity was measured by two approaches, culture dependent and independent strategies. The results showed that the KHA samples were dominated by gama-proteobacteria while the KHB samples were dominated by crenorchaeta (arkhae) and gama-proteobacteria. The organisms from KHA samples were less variation compared to that the KHB. From both hot springs we found a few uncultured organisms from culture dependent strategy and a few unidentified organisms based on phylogenetic analysis.

 

Bioremediation Studies for the Clean-Up of Chlorinated Herbicide-Treated Agricultural Soils

V. Morgante, P. Miralles, M. Hernández, C. Flores, M. González and M. Seeger*

Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Deparíamenío de Química and Millennium Nucleus of Microbial Ecology and Environmental Microbiology and Biotechnology EMBA, Universidad Técnica Federico Santa María, Valparaíso, Chile. * E-mail: michael.seeger@usm. cl

Keywords: Bioremediation; chlorinated herbicide; agricultural soils

Herbicides are used world widely in agriculture and forestry. Chlorinated s-triazine herbicides (simazine, atrazine) are released in cultivation fields for weed control. Their persistence in the environment and potential toxicity for living organisms is of increasing concern. s-Triazines have been detected in surface and ground water in North America, Europe and Australia. Recently, s-triazines have been determined in watersheds close to agricultural fields in Chile. Bioremediation is an important biotechnology for the removal of persistent organic pollutants from soils. The low cost and in situ application are important advantages of this technology. The aim of this report was to analyze the effect of bioremediation on the fate of the herbicide simazine in agricultural soils. The native bacterium Pseudomonas nitroreducens MHP41 was characterized and selected as catalyst for the bioremediation studies. To describe simazine retention and availability in agricultural soils, batch experiments were conducted and the sorption coefficient was determined.

Herbicide depletion in soil microcosms was analyzed by HPLC. Microbial community changes during bioaugmentation were studied by cultivation-independent methods such as T-RFLP and FISH. Field studies were also performed. Distribution coefficient indicated moderate adsorption of simazine to these agricultural soils. Microcosm studies showed an increased degradation of the herbicide simazine in soil by bioaugmentation with P. nitroreducens MHP41. Microbial community analysis revealed that bioaugmentation with the bacterial strain MHP41 promotes changes in the structure of the soil microbiota. Acidobacteria, a-Proteobacteria and Planctomycetes are the phylogenetic groups most affected by bioaugmentation. In field studies, herbicide depletion was observed under natural environmental conditions using bioaugmentation. The fate of s-triazines in soil depends on physico-chemical as well as biological processes. Successful simazine biodegradation in agricultural soils was achieved by bioaugmentation with P. nitroreducens strain MHP41. This study showed that bioremediation could be useful for the clean-up of agricultural soils treated with pesticides.

Acknowledgments: MS acknowledges financial support of Millennium Nucleus EMBA P04/007-F and USM 130836 grants. MH and VM gratefully acknowledge CONICYT and MECESUP-UCV-0206 fellowships, respectively.

 

The Environmental Impact of Lignite Fly Ash Interacted with Quality of Soil and Rice Plant

O. Siriratpiriya*

The Environmental Research Institute, Chulalongkorn University, Bangkok 10330, Thailand. *E-mail: Orawan.Si@Chula.ac.th

Keywords: Lignite fly ash; heavy metals; plant nutrients

Lignite fly ash, a byproduct of coal combustion, was produced 75-85 % of total ash. 6,000-9,000 tones fly ash/day is a production from lignite electric power utility Mae Mao, Lumpang Province. Chemical composition of lignite fly ash consist of essential elements for plant and animal for both macroelements (P, Ca, K, S, Mg, etc.) and trace elements (Fe, Zn, Cu, Mn, Si, etc.) on one hand while another was contaminated with toxic heavy metals (Cd, Pb, Hg, Ni, As, etc.). Currently, fly ash is used in cement and concrete structures, brick manufacturing, golf ball and agricultural product as soil amendment because of its spherical-shape and hollow particle. Lignite fly ash, therefore possesses not only advantageous properties supported plant growth but also having the ability to inhibit plant growth such as heavy metals and particle size. Hence, the characteristics of lignite fly ash is important for effective the ash disposing and chemical composition is essential in assessing the environmental impact of lignite fly ash utilization. To clarify the possible positive and negative environmental impact of lignite fly ash interacted with quality of soil and rice plant, field experiment was conducted at paddy field of Amphore Mueng, Nakorn Nayok Province. The average particle size of lignite fly ash in this study was 155 um, ranging from 0.49 to 830 um, with spherical-shape and hollow. The experimental design was randomized complete block (RCB) with 3 replications of 4 application rate (0.5, 1, 2 and 4 t fly ash rai-1) (1 ha = 6.25 rai). The result indicated that application of lignite fly ash 0.5-4 tones rai-1 to clay soil (soil pH = 5.16) resulted in increasing soil pH around one pH unit. Moreover, Mn, Se, Si, Zn, As, and Cd also increased by increasing application rate of lignite fly ash when 0.005 M DTPA was used as soil extractant. The ash was sufficient potassium (K20) and magnesium (Mg) sources for plant growth with safe dose at the maximum rate 2 t fly ash rai-1 based on the heavy metal concentrations. In addition, root weight, root length and rice yield also were increased significantly. Lignite fly ash, therefore can be interacted as soil amendment to improve physical property of the soil and to avail as nutrients source for growth of rice with safe dose at the rate of 2 t fly ash rai-1. The significant factors of lignite fly ash utilization lead to positive environmental impact included soil property, physical property and chemical composition of the ash, essential elements for plant and risk of heavy metals.

Oil-Contaminated Soil Microorganism: Isolation and Characterization for Biodiesel Production

G. Ciudad1*, R. Briones2, J. Leal3, M. Jorquera4, L. Azocar3 and R. Navia1

1Departamento de Ingeniería Química, 2Programa de Magíster en Ciencias, de la Ingeniería m. Biotecnología, 3Programa de Doctorado en Ciencias de Recursos Naturales, 4Centro de Ciencias y Biotecnología de Recursos Naturales. Universidad de La Frontera, Casilla 54-D, Temuco, Chile. *E-mail: gciudad@ufro.cl

Keywords: Oil-contaminated soil; microorganisms; biodiesel.

Lipase producing microorganisms (LPM) may catalyze hydrolysis or transesterification of triacylglycerols to fatty acids alkyl esters (biodiesel). In this sense, the main objective of this work was to isolate and identify LPM in oil and grease contaminated soil for future applications in biodiesel production from rapeseed oil. Samples from contaminated soil (with rapeseed oil), from an industrial facility and contaminated soil (with salmon grease) near to a fish wastewater treatment plant were collected. The samples were first inoculated at 150 rpm and 30°C in a liquid enriched selective medium (70g L-1 polypeptone, 1 g L-1 NaNO3, 1 g L-1 KH2PO4, 0.5 g L-1 MgS04 7H20, and 30 g L-1 rapeseed oil as sole carbon source). Then, agar was added to the same medium for counting and isolating colonies at 20° C (solid medium). The colonies that showed growth were chosen. The characterization was carried out by 16S ribosomal RNA gene sequencing using the following primers: EUB933F, 358F and 907R. Lipase activity was measured spectrophotometrically using ρ-nitrophenyl-palmitate as substrate. Nine strains were isolated and characterized based on their ability to grow in rapeseed oil as the sole carbon source (7 from salmon grease contaminated soil and 2 from rapeseed oil contaminated soil). All strains were Bacteria domain. In salmon grease contaminated soil Myroide, Arthrobacter, Bacillus and Serratia genus were identified, whereas in rapeseed oil contaminated soils only Bacillus genus was identified. All strains showed lipase activity, being the highest 696 U (Myroide) and the lowest 118 U (Serratia). It is shown that soil contaminated with rapeseed oil or fish grease are possible sources of LPM, which could be useful in novel and innovative future applications for biodiesel production, such as whole-cell biocatalysts that unlike commercial lipase, requires no purification or complicate immobilization methods, minimizing biodiesel production process costs.

Acknowledgements: This work was sponsored by the Chilean FONDECYT Project 3080021, Chilean FONDEF Project D05I10391 and partially supported by the Bicentenary Program in Science and Technology from CONICYT-Chile, through Grants PSD26 and TPI-16.

 

Ecological, Biochemical and Molecular Mechanisms Involved in Nutrient Acquisition and Heavy Metal Stress Alleviation by Mycorrhizal Plants

J.M. Barea*

Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Prof. A lb are da 1, 18008, Granada, Spain. *E-mail: josemiguel.barea@eez.csic.es

Keywords: Nutrient acquisition; heavy metals stress; mycorrhizal plants.

Mycorrhizas are mutualistic fungal-root symbiosis established by specialized soil-borne fungi and the majority of land plants. Arbuscular mycorrhiza (AM) is the most common mycorrhizal type which is formed by more than 80 % of plant species including almost all of the agronomical interest, and herbaceous and shrub species in natural ecosystems. The AM fungi are ubiquitous microbial fungi, whose origin and divergence have been dated back to more than 450 million years ago to critically contribute to plant evolution on Earth.

The AM fungi, after colonization of the root cortex of the host plant, improve plant capacity for nutrient acquisition. The AM role in nutrient supply to plants is exerted by the AM mycelium linking the geo-chemical and biotic portions of the soil ecosystem, thereby affecting rates and patterns of P and N cycling in both agricultural and natural ecosystems. In addition, the AM symbiosis improves plant health through increased protection against environmental stresses, whether they be biotic (e.g. pathogen attack) or abiotic (e.g. drought, salinity, heavy metals, organic pollutants), being able to enhance soil structure, through the formation of the aggregates necessary for good soil quality. The AM fungi can be therefore considered as an integral component to the function of root systems, usually acting in cooperation with other soil microorganisms in the so-called "mycorrhizosphere".

The available information on the impact of AM fungi on plant functioning in both agricultural and natural systems, with special emphasis in stresses soils, is analyzed in this presentation. After a brief introduction of the AM fungal and symbiosis biology, the information is systematized as follows: (i) ecological, biochemical and molecular bases of the AM role on plant acquisition of P and N, in low-nutrient and degraded soils; (ii) ecological, biochemical and molecular bases of the AM role in increasing plant tolerance to heavy metals (HM); and (iii) evaluating the possibilities to use these micro-fungi as an environmental biotechnology tool for improving plant developments in low-nutrient and/or HM-contaminated environments.

 

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