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Isolation of Antibiotics-degrading Soil Bacteria
Eun Hea JHO,Seon Hee KIM,Jinkyung HONG 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
Antibiotics are widely used to treat animals and crops from infections. In Korea, 6 antibiotics (streptomycin, oxytetracycline, oxolinic acid, kasugamycin, validamycin, polyoxin) have been registered and used for agricultural purposes. These antibiotics can remain in the soil and adversely affect soil microorganisms, but at the same time, they can be slowly degraded by soil microorganisms. In this study, antibiotic-degrading bacteria were to be isolated from agricultural soils. One field soil sample and one rice paddy soil sample was used to separate soil bacteria and cultured in the minimal medium with the target antibiotics, validamycin, as the sole carbon source. The bacterial growth (i.e., optical density) was measured at 600 ㎚. The degradability of the target antibiotics is to be studied by measuring the residual concentrations of validamycin every 7 days for 28 days. The degradation of validamycin and the changes in the microbial community structure of the separated bacteria after validamycin injection are to be reported in this study.
Jho, Eun Hea,Im, Jinwoo,Yang, Kyung,Kim, Young-Jin,Nam, Kyoungphile Elsevier 2015 CHEMOSPHERE - Vol.119 No.-
<P><B>Abstract</B></P> <P>This study was set to investigate the changes in the toxicity of arsenic (As)-contaminated soils after washing with phosphate solutions. The soil samples collected from two locations (A: rice paddy and B: forest land) of a former smelter site were contaminated with a similar level of As. Soil washing (0.5M phosphate solution for 2h) removed 24.5% As, on average, in soil from both locations. Regardless of soil washing, Location A soil toxicities, determined using Microtox, were greater than that of Location B and this could be largely attributed to different soil particle size distribution. With soils from both locations, the changes in As chemical forms resulted in either similar or greater toxicities after washing. This emphasizes the importance of considering ecotoxicological aspects, which are likely to differ depending on soil particle size distribution and changes in As chemical forms, in addition to the total concentration based remedial goals, in producing ecotoxicologically-sound soils for reuse. In addition, calcium phosphate used as the washing solution seemed to contribute more on the toxic effects of the washed soils than potassium phosphate and ammonium phosphate. Therefore, it would be more appropriate to use potassium or ammonium phosphate than calcium phosphate for phosphate-aided soil washing of the As-contaminated soils.</P> <P><B>Highlights</B></P> <P> <UL> <LI> As removal by soil washing may not reduce soil toxicity of As-contaminated soils. </LI> <LI> Negligible changes in soil toxicity could be due to changes in As chemical forms. </LI> <LI> Soil particle size distribution could affect soil toxicity following soil washing. </LI> <LI> Type of cations associated with phosphate affected toxicities of the washed soils. </LI> <LI> Ecotoxicological aspects need to be considered for reuse of soil after soil washing. </LI> </UL> </P>
Jho, Eun Hea,Jung, Jae‐,Woong,Nam, Kyoungphile John Wiley Sons, Ltd 2013 Journal of chemical technology and biotechnology Vol.88 No.8
<P><B>Abstract</B></P><P><B>BACKGROUND</B></P><P><B>Military areas such as firing ranges have serious contamination problems due to both heavy metals and nitroaromatic compounds (NACs). The feasibility of modified Fenton reactions for remediation of NACs is studied by investigating the fate of lead (Pb) and copper (Cu) during the modified Fenton reactions and its effect on the degradation of 2,4‐dinitrotoluene (2,4‐DNT) in soils at various hydrogen peroxide (H<SUB>2</SUB>O<SUB>2</SUB>) concentrations.</B></P><P><B>RESULTS</B></P><P><B>During the reactions, the Pb fate was not affected at ≤0.2 mol L<SUP>−1</SUP> H<SUB>2</SUB>O<SUB>2</SUB>, but final aqueous phase Pb was higher in the samples than in the controls at >0.2 mol L<SUP>−1</SUP> H<SUB>2</SUB>O<SUB>2</SUB>. These changes in the Pb fate resulted in interference with 2,4‐DNT degradation at ≥0.2 mol L<SUP>−1</SUP> H<SUB>2</SUB>O<SUB>2</SUB>. Similarly, aqueous phase Cu was higher in samples with >0.2 mol L<SUP>−1</SUP> H<SUB>2</SUB>O<SUB>2</SUB> than in the controls; however, unlike Pb, these changes did not have adverse effects on 2,4‐DNT degradation.</B></P><P><B>CONCLUSION</B></P><P><B>The different effects of heavy metals such as Pb and Cu on 2,4‐DNT degradation in soils during modified Fenton reactions need to be understood to optimize 2,4‐DNT degradation performance. The results help to advance the Fenton reaction applications for the remediation of soils contaminated with Pb or Cu and 2,4‐DNT mixtures. © 2012 Society of Chemical Industry</B></P>
Degradation of Oxytetracycline by Persulfate Activation Using Hand Warmer Waste
Eun Hea JHO,Youn Jun LEE,Chang-gu LEE 한국생물공학회 2021 한국생물공학회 학술대회 Vol.2021 No.10
Reactive radical species are widely used for the removal of organic compounds in wastewater. These species are usually generated by activating peroxides (eg., hydrogen peroxide, persulfate, peroxymonosulfate) using catalysts. Among various catalysts, iron-based catalysts such as ferrous, ferric, and iron oxide are widely used for the activation of peroxide because it is effective and less expensive. In this study, waste of hand warmer was magnetically separated and was used as a persulfate activator for the removal of antibiotics, oxytetracycline. The degradation of oxytetracycline in the presence of catalyst and persulfate was studied by analyzing residual concentration of oxytetracycline in the samples. The removal ratio of oxytetracycline by persulfate activation was more than 99% for 5 min of reaction time at pH 6. In addition, the reuse test revealed that the catalyst can be reused for 8 cycles. The results suggest that the hand warmer waste can be an efficient catalyst for persulfate activation.
Effect of co-presence of cadmium or procymidone with microplastic films in soil on lettuce growth
Jho Eun Hea,Yang Ji Won,Ju Won Jung,Lee Sung-Jong,Hasan Md Mehedee 한국응용생명화학회 2023 Applied Biological Chemistry (Appl Biol Chem) Vol.66 No.-
Agricultural environment is often contaminated with various chemicals (e.g., pesticides, heavy metals) and microplastics due to the uses of plastic products. The effects of chemical contaminants or microplastics on terrestrial environment have been extensively studied, but the studies on the co-presence of chemical contaminants and microplastics are relatively limited. This study was set to investigate the effect of co-presence of microplastics (i.e., low-density polyethylene (LDPE) and polyvinyl chloride (PVC) microplastic films) and chemical contaminants (i.e., cadmium (Cd) and procymidone (PCM)) in soil on the lettuce growth and Cd and PCM uptake by lettuce using pot tests. The lettuce leaf lengths were not affected by the presence of only Cd or PCM, but the rates of change in the lettuce leaf number were adversely affected by the presence of PCM. The presence of only LDPE or PVC in soil at the concentrations used in this study did not have significant impacts on the lettuce growth. But the co-presence of Cd and LDPE and the co-presence of PCM and PVC resulted in the negligible increases in the lettuce leaf length and leaf number with time, although the lettuce growths were statistically similar in the Cd- or PCM-contaminated soils regardless of the presence of microplastics. The results suggest that the adverse effects of Cd or PCM can be intensified by the co-presence of microplastics, and the effects can be different depending on the types of microplastics. The promoted adverse effects of chemical contaminants in the co-presence of microplastics can be supported by the tendency of the increased absorption of Cd or PCM by lettuce in the co-presence of microplastics. Overall, this study shows the need for management of both chemical contaminants and microplastics that may reside in the agricultural environment.