Citation
Bioremediation of mining-impacted soils through the restoration of bacterial communities enhancing revegetation

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Title:
Bioremediation of mining-impacted soils through the restoration of bacterial communities enhancing revegetation
Creator:
Huizar, Nancy Moreno ( Author, primary )
Roane, T.M. ( Faculty mentor )
Place of Publication:
Denver, CO
Publisher:
University of Colorado Denver
Publication Date:
Language:
English

Notes

Abstract:
Bioremediation is the use of organisms to reduce or eliminate the toxicity of contaminants in the environment. The bioremediation of microbially deficient miningimpacted soils can involve restoration of bacterial communities through the addition of microorganisms from unimpacted soils. Soil-borne bacteria are able to detoxify metals through the production of exopolymers, siderophores, biosurfactants, metallothioneins, metal efflux systems, and metal methylation. Introduction of metal detoxification can increase opportunities for plant growth and plant-based stabilization of metal-impacted soils. The overall goal of this project is to enhance the ability of mining-impacted soils to support plant vegetation. By doing so, this will reduce the spread of toxic metals through erosion and weathering. The specific objectives are to assess the bacterial community composition differences among varying ratios of mining-impacted soils mixed with unimpacted soils, and to assess which ratios result in increased plant biomass and growth. To address these objectives, plant-based greenhouse studies, along with genetic-based bacterial identification methods, will be conducted. The anticipated results are increased plant productivity in ratios of increased unimpacted soil due to the introduced bacterial diversity.

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Source Institution:
University of Colorado Denver
Holding Location:
Auraria Library
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All applicable rights reserved by the source institution and holding location.

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Bioremediation of Mining-impacted Soils Through the Restoration of Bacterial Communities Enhancing Revegetation N. Moreno Huizar* and T.M. Roane Department of Integrative Biology University of Colorado Denver Introduction Mining-impacted soils have toxic metal concentrations that diminish bacterial communities. Metals bind to many cellular ligands, displacing essential metals from their normal binding site. This can result in lack of nutrients for the organism.1 Soil-borne bacteria have general and metal specific mechanisms of metal resistance (Figure 1).1 Mining-impacted soils lack the nutrients necessary for plant growth. Without vegetation, soils are prone to erosion and weathering that then cause the spread of toxic metal concentrations to other essential systems such as water sources.1 Remediation of miningimpacted soils is necessary to reestablish bacterial communities and vegetation. The mixing of mining-impacted and unimpacted soil is a novel remediation strategy and has been shown to be effective by diluting metal concentrations. Previous research has also shown a resulting change in bacterial communities. The work proposed here will assess whether mixing mining-impacted and unimpacted soils can improve plant growth and revegetation of metal impacted soils. Results of this research will add support to the existing studies.2,3 Objective 2: To assess the bacterial community composition differences among varying ratios of miningimpacted soils mixed with unimpacted soils Approach: Soil samples will be collected, from each pot, using autoclaved utensils. DNA extraction will then be conducted on each sample using PowerSoil DNA Isolation Kits produced by MOBIO, PCR will be done to amplify DNA and Illumina high-throughput sequencing will be preformed to correlate DNA with microorganism. Predicted results: The less mining-impacted soil, the greater the bacterial community composition differences will be. Metal resistant bacteria are likely to be more abundant, possibly through transform of bacterial communities in the unimpacted soil. Objective 1:To assess which ratios result in increased plant biomass and growth. Bioremediation is the use of organisms to reduce or eliminate the toxicity of contaminants in the environment. The bioremediation of microbially deficient miningimpacted soils can involve restoration of bacterial communities through the addition of microorganisms from unimpacted soils. Soil-borne bacteria are able to detoxify metals through the production of exopolymers, siderophores, biosurfactants, metallothioneins metal efflux systems, and metal methylation. Introduction of metal detoxification can increase opportunities for plant growth and plant-based stabilization of metal-impacted soils. The overall goal of this project is to enhance the ability of mining-impacted soils to support plant vegetation. By doing so, this will reduce the spread of toxic metals through erosion and weathering. The specific objectives are to assess the bacterial community composition differences among varying ratios of mining-impacted soils mixed with unimpacted soils, and to assess which ratios result in increased plant biomass and growth. To address these objectives, plant-based greenhouse studies, along with genetic-based bacterial identification methods, will be conducted. The anticipated results are increased plant productivity in ratios of increased unimpacted soil due to the introduced bacterial diversity. Abstract Acknowledgements Thank you to Dr. Timberley Roane for assistance in the project. Figure 1: Microbial metal-resistant mechanisms.1 Approach Four ratios, 1) 0:1, 2) 1:0, 3) 1:1, and 4) 1:2 of mining-impacted to unimpacted soil were chosen at random. Zero metal soil (potting soil) was used as a control. The ratios were mixed by hand and added to pots containing window screen to prevent excess soil loss in watering tray. Two Standard Fast Plant seeds were added to each pot at a depth equal to the diameter of the seed. The pots were incubated under continuous light in the CU Denver research greenhouse. Results: Plant growth was observed qualitatively. Germination was observed on soils 1, 3, 4 and control after 24 hours and germination of soil 2 was observed after 48 hours. Plants increased in height in soils 1 and control only, with control having the greatest height. Flowering of controls was observed 24 hours before flowering of plants in soil 1. Plant biomass will be assessed by weighing plant outside of the pot. References 1.! Roane, TM and IL Pepper. 2000. Microorganisms and Metal Pollutants. Environmental Microbiology, Maeier RM Gerba, CP and Pepper IL (eds). 403-423. 2.! Yao, Z., Li, J., Xie, H., & Yu, C. (2012). Review on remediation technologies of soil contaminated by heavy metals. Procedia Environmental Science,16, 722-729. Doi: 10.1016/ j.proenv.2012.10.099 3.! Stefanowicz, M. A., Niklinska, M., & Laskowski, R. (2008). Metals affect soil bacterial and fungal functional diversity differently. Environmental Toxicology and Chemistry, 27(3), 591-598. Doi: 10.1897/07-288.1 Figure 5: Pot set up in watering tray. Figure 4: Pots used with window screen addition. Figure 2: CUDenver greenhouse. Figure 7: Contained mine tailings (left ) and acid mine drainage (right). (adopted from http://www.groundtruthtrekking.org/Issues/MetalsMining/MineTailings.html and Google images). Figure 3: Standard Fast Plant seeds. Figure 6: Plants in control (left ) and soil 1 (right). *Presenting Author: Nancy Moreno Huizar University of Colorado Denver Department of Integrative Biology Campus Box 171, PO Box 173364 Denver, CO 80217-3364 Nancy.morenohuizar@ucdenver.edu Overall Goal: To enhance the ability of mining-impacted soils to support plant vegetation. Objectives of the Present Study Objective 1: To assess which ratios of mining impacted and unimpacted soils result in increased plant biomass and growth. Objective 2: To assess the bacterial community composition differences among varying ratios of mining-impacted soils mixed with unimpacted soils. Objectives Future Directions Quantitative analysis of plant biomass and growth will be conducted. More soil ratios will be tested Metal resistant bacteria will be investigated as an additional amendment to miningimpacted soils as a second remediation approach.

PAGE 2

Bioremediation of Mining-impacted Soils Through the Restoration of Bacterial Communities Enhancing Revegetation N. Moreno Huizar* and T.M. Roane Department of Integrative Biology University of Colorado Denver Introduction Mining-impacted soils have toxic metal concentrations that diminish bacterial communities. Metals bind to many cellular ligands, displacing essential metals from their normal binding site. This can result in lack of nutrients for the organism.1 Soil-borne bacteria have general and metal specific mechanisms of metal resistance (Figure 1).1 Mining-impacted soils lack the nutrients necessary for plant growth. Without vegetation, soils are prone to erosion and weathering that then cause the spread of toxic metal concentrations to other essential systems such as water sources.1 Remediation of miningimpacted soils is necessary to reestablish bacterial communities and vegetation. The mixing of mining-impacted and unimpacted soil is a novel remediation strategy and has been shown to be effective by diluting metal concentrations. Previous research has also shown a resulting change in bacterial communities. The work proposed here will assess whether mixing mining-impacted and unimpacted soils can improve plant growth and revegetation of metal impacted soils. Results of this research will add support to the existing studies.2,3 Objective 2: To assess the bacterial community composition differences among varying ratios of miningimpacted soils mixed with unimpacted soils Approach: Soil samples will be collected, from each pot, using autoclaved utensils. DNA extraction will then be conducted on each sample using PowerSoil DNA Isolation Kits produced by MOBIO, PCR will be done to amplify DNA and Illumina high-throughput sequencing will be preformed to correlate DNA with microorganism. Predicted results: The less mining-impacted soil, the greater the bacterial community composition differences will be. Metal resistant bacteria are likely to be more abundant, possibly through transform of bacterial communities in the unimpacted soil. Objective 1:To assess which ratios result in increased plant biomass and growth. Bioremediation is the use of organisms to reduce or eliminate the toxicity of contaminants in the environment. The bioremediation of microbially deficient miningimpacted soils can involve restoration of bacterial communities through the addition of microorganisms from unimpacted soils. Soil-borne bacteria are able to detoxify metals through the production of exopolymers, siderophores, biosurfactants, metallothioneins metal efflux systems, and metal methylation. Introduction of metal detoxification can increase opportunities for plant growth and plant-based stabilization of metal-impacted soils. The overall goal of this project is to enhance the ability of mining-impacted soils to support plant vegetation. By doing so, this will reduce the spread of toxic metals through erosion and weathering. The specific objectives are to assess the bacterial community composition differences among varying ratios of mining-impacted soils mixed with unimpacted soils, and to assess which ratios result in increased plant biomass and growth. To address these objectives, plant-based greenhouse studies, along with genetic-based bacterial identification methods, will be conducted. The anticipated results are increased plant productivity in ratios of increased unimpacted soil due to the introduced bacterial diversity. Abstract Acknowledgements Thank you to Dr. Timberley Roane for assistance in the project. Figure 1: Microbial metal-resistant mechanisms.1 Approach Four ratios, 1) 0:1, 2) 1:0, 3) 1:1, and 4) 1:2 of mining-impacted to unimpacted soil were chosen at random. Zero metal soil (potting soil) was used as a control. The ratios were mixed by hand and added to pots containing window screen to prevent excess soil loss in watering tray. Two Standard Fast Plant seeds were added to each pot at a depth equal to the diameter of the seed. The pots were incubated under continuous light in the CU Denver research greenhouse. Results: Plant growth was observed qualitatively. Germination was observed on soils 1, 3, 4 and control after 24 hours and germination of soil 2 was observed after 48 hours. Plants increased in height in soils 1 and control only, with control having the greatest height. Flowering of controls was observed 24 hours before flowering of plants in soil 1. Plant biomass will be assessed by weighing plant outside of the pot. References 1. Roane, TM and IL Pepper. 2000. Microorganisms and Metal Pollutants. Environmental Microbiology, Maeier RM Gerba, CP and Pepper IL (eds). 403-423. 2. Yao, Z., Li, J., Xie, H., & Yu, C. (2012). Review on remediation technologies of soil contaminated by heavy metals. Procedia Environmental Science,16, 722-729. Doi: 10.1016/ j.proenv.2012.10.099 3. Stefanowicz, M. A., Niklinska, M., & Laskowski, R. (2008). Metals affect soil bacterial and fungal functional diversity differently. Environmental Toxicology and Chemistry, 27(3), 591-598. Doi: 10.1897/07-288.1 Figure 5: Pot set up in watering tray. Figure 4: Pots used with window screen addition. Figure 2: CUDenver greenhouse. Figure 7: Contained mine tailings (left ) and acid mine drainage (right). (adopted from http://www.groundtruthtrekking.org/Issues/MetalsMining/MineTailings.html and Google images). Figure 3: Standard Fast Plant seeds. Figure 6: Plants in control (left ) and soil 1 (right). *Presenting Author: Nancy Moreno Huizar University of Colorado Denver Department of Integrative Biology Campus Box 171, PO Box 173364 Denver, CO 80217-3364 Nancy.morenohuizar@ucdenver.edu Overall Goal: To enhance the ability of mining-impacted soils to support plant vegetation. Objectives of the Present Study Objective 1: To assess which ratios of mining impacted and unimpacted soils result in increased plant biomass and growth. Objective 2: To assess the bacterial community composition differences among varying ratios of mining-impacted soils mixed with unimpacted soils. Objectives Future Directions Quantitative analysis of plant biomass and growth will be conducted. More soil ratios will be tested Metal resistant bacteria will be investigated as an additional amendment to miningimpacted soils as a second remediation approach.