Investigating the potential of urease active fungi in remediating Sr polluted water
(2024) BIOM02 20241Degree Projects in Biology
- Abstract
- This study investigates the potential of urease-positive fungus strains to form calcium carbonate via urea hydrolysis. Besides, we compare the precipitation ability of living and dead biomass of fungus to determine which one has better strontium removal performance. The first hypothesis was that the Sr removal efficiency of living biomass of fungus cultivated without Ca was expected to be lower than that grown with Ca since Ca2+ is a crucial component for producing precipitation. Besides, the living biomass of fungi can use both metabolism and non-metabolism-dependent biosorption mechanisms, so the second hypothesis was that the living biomass of fungi would perform at a higher Sr removal efficiency than dead fungi. The results did not... (More)
- This study investigates the potential of urease-positive fungus strains to form calcium carbonate via urea hydrolysis. Besides, we compare the precipitation ability of living and dead biomass of fungus to determine which one has better strontium removal performance. The first hypothesis was that the Sr removal efficiency of living biomass of fungus cultivated without Ca was expected to be lower than that grown with Ca since Ca2+ is a crucial component for producing precipitation. Besides, the living biomass of fungi can use both metabolism and non-metabolism-dependent biosorption mechanisms, so the second hypothesis was that the living biomass of fungi would perform at a higher Sr removal efficiency than dead fungi. The results did not show significance in Sr removal, whether cultivating with Ca or not. Sr has similar characteristics to Ca, which might influence the precipitation process. Furthermore, dead biomass of fungus removed more Sr than living fungi because the toxicity of Sr would not influence them and have a larger surface area. However, living urease-active fungi still have a significant potential for Sr remediation. Future studies could focus on optimizing growth conditions and controlling fungal biomass to improve Sr removal efficiency. (Less)
- Popular Abstract
- Investigating the potential of urease active fungi in remediating Sr polluted water
Nuclear energy development has been under scrutiny as a zero-emission clean energy source due to severe consequences of potential accidents, which might release many radionuclides, such as strontium (Sr), into the water environment. The toxicity of Sr on aquatic organisms is a significant concern. Therefore, radio pollution must be solved effectively and efficiently to ensure sustainable development. Urease active fungi as biosorbents might be a more sustainable alternative to traditional techniques. The process involves microbial-induced calcium carbonate precipitation (MICP), in which urease hydrolyzes urea and forms carbonate ions, and subsequent... (More) - Investigating the potential of urease active fungi in remediating Sr polluted water
Nuclear energy development has been under scrutiny as a zero-emission clean energy source due to severe consequences of potential accidents, which might release many radionuclides, such as strontium (Sr), into the water environment. The toxicity of Sr on aquatic organisms is a significant concern. Therefore, radio pollution must be solved effectively and efficiently to ensure sustainable development. Urease active fungi as biosorbents might be a more sustainable alternative to traditional techniques. The process involves microbial-induced calcium carbonate precipitation (MICP), in which urease hydrolyzes urea and forms carbonate ions, and subsequent precipitation of calcium carbonate (CaCO₃), which can incorporate Sr ions. This work aimed to select urease-positive fungal species and investigate the formation of calcium carbonate via urea hydrolysis. This was done to understand better whether Sr could be sequestered into CaCO₃ or coprecipitated alongside it. Additionally, we compared the precipitation capabilities of living versus dead fungi to determine which method offers superior Sr removal performance.
The experiment was divided into two parts: 1. Identify the fungal species with the highest precipitation ability for Sr removal by measuring CaCO3 precipitation and fungal biomass under different urea concentrations. 2. Compare the Sr removal efficiency of living versus dead fungi candidates in Sr-containing mediums with and without Ca to assess the role of urease activity in CaCO3 precipitation. We hypothesized that living fungi would exhibit higher Sr removal efficiency than dead fungi due to their ability to utilize metabolic (MICP)and non-metabolic dependent biosorption mechanisms. Conversely, dead fungi biomass could only use non-metabolic mechanisms. Besides, living fungi were expected to perform better in Ca conditions as they could produce CaCO3, facilitating Sr coprecipitation.
Among all the fungi species, strain N1.5 stood out, showing the highest biomass and CaCO3 production. This makes it the most promising candidate for further Sr removal experiments. However, our hypothesis was not fully supported by the results. Living strain N1.5 did not show a significant difference in Sr removal between the media with and without Ca. Surprisingly, dead N1.5 removed more Sr from the medium containing Ca²⁺compared to living N1.5. In the medium without Ca²⁺, there was no significant difference between the Sr removal by living and dead fungi. Several factors could explain these results, including the chemical properties of Ca and Sr, which can lead to substitutions in the crystal structure, influencing the production of calcite precipitation. Dead fungi showed higher strontium removal rates, possibly due to less aggregation of biomass, greater cell surface area for adsorbing Sr, and not being affected by the toxicity of Sr. The higher Sr concentration may hinder fungal growth, and nitrogen abundance in the YMG medium may reduce urea hydrolysis, thereby affecting Sr removal. Shorter incubation times may have limited enzyme activity, thereby reducing CaCO3 precipitation for Sr capture. Using urea as the sole nitrogen source and extending the incubation time may improve the Sr removal efficiency. Despite these findings, living urease-active fungi still hold significant potential in Sr remediation. Future studies could focus on optimizing growth conditions and controlling fungal biomass to improve Sr removal efficiency.
Master’s Degree Project in Biology/Aquatic Ecology/ 30 credits 2024
Department of Biology, Lund University
Advisor: Hanbang Zou
Advisors Unit/Department (or Company or Authority) (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9157551
- author
- Liu, Feng-Hsiu
- supervisor
-
- Hanbang Zou LU
- organization
- course
- BIOM02 20241
- year
- 2024
- type
- H2 - Master's Degree (Two Years)
- subject
- language
- English
- id
- 9157551
- date added to LUP
- 2024-06-03 16:08:24
- date last changed
- 2024-06-03 16:08:24
@misc{9157551,
abstract = {{This study investigates the potential of urease-positive fungus strains to form calcium carbonate via urea hydrolysis. Besides, we compare the precipitation ability of living and dead biomass of fungus to determine which one has better strontium removal performance. The first hypothesis was that the Sr removal efficiency of living biomass of fungus cultivated without Ca was expected to be lower than that grown with Ca since Ca2+ is a crucial component for producing precipitation. Besides, the living biomass of fungi can use both metabolism and non-metabolism-dependent biosorption mechanisms, so the second hypothesis was that the living biomass of fungi would perform at a higher Sr removal efficiency than dead fungi. The results did not show significance in Sr removal, whether cultivating with Ca or not. Sr has similar characteristics to Ca, which might influence the precipitation process. Furthermore, dead biomass of fungus removed more Sr than living fungi because the toxicity of Sr would not influence them and have a larger surface area. However, living urease-active fungi still have a significant potential for Sr remediation. Future studies could focus on optimizing growth conditions and controlling fungal biomass to improve Sr removal efficiency.}},
author = {{Liu, Feng-Hsiu}},
language = {{eng}},
note = {{Student Paper}},
title = {{Investigating the potential of urease active fungi in remediating Sr polluted water}},
year = {{2024}},
}