Publications

Detailed Information

Synthesis of carbon quantum dot from spent coffee ground exhibiting visible-light-driven antimicrobial activity against Escherichia coli O157:H7 : Spent Coffee Ground (SCG)유래의 Carbon Quantum dot(CQD) 합성 및 광촉매 작용을 이용한 Escherichia coli O157:H7 저감화

DC Field Value Language
dc.contributor.advisorDong-Hyun Kang-
dc.contributor.author김지영-
dc.date.accessioned2024-05-31T18:01:01Z-
dc.date.available2024-05-31T18:01:01Z-
dc.date.issued2023-
dc.identifier.other000000174749-
dc.identifier.urihttps://hdl.handle.net/10371/204007-
dc.identifier.urihttps://dcollection.snu.ac.kr/common/orgView/000000174749ko_KR
dc.description학위논문(석사) -- 서울대학교대학원 : 농업생명과학대학 농생명공학부, 2023. 2. Dong-Hyun Kang .-
dc.description.abstractThe aim of this study was to synthesize carbon quantum dot (CQD) exhibiting visible-light-driven (VLD) antimicrobial activity using spent coffee ground (SCG) as biomass. CQD was synthesized from SCG through microwave treatment. It was confirmed that typical CQD was synthesized through analysis of morphology (high-resolution transmission electron microscopy), size distribution (dynamic light scattering), and chemical structure (X-ray photoelectron spectroscopy). VLD antimicrobial activities of CQD synthesized from SCG against Escherichia coli O157:H7 were found to be increased as pH decreased. Fluorescence quantum yield (FLQY), band gap energy (Eg), and fluorescence lifetime as photodynamic properties of CQD related to VLD antimicrobial activity did not show any significant changes according to pH change. On the other hand, as pH decreased, negative zeta potential (mV) values of CQD and pathogenic bacteria gradually decreased. As a result, it was confirmed that CQD uptake into E. coli O157:H7 was gradually increased due to a decrease in repulsive force between them. It was confirmed that major reactive oxygen species (ROS) that contributed to the inactivation of E. coli O157:H7 was singlet oxygen. In addition, it was found that as pH decreased, activities of enzymes (superoxide dismutase and catalase) known to scavenge ROS in cells decreased. In the presence of CQD, when visible light was applied, the amount of ROS generated inside the cell increased as the pH decreased. In addition, VLD antimicrobial activities of CQD were applied to the apple slices washing and significant (P < 0.05) reduction of E. coli O157:H7 occurred in both apple and liquid, and cross-contamination was also prevented. The activity of CQD was maintained after reuse for three consecutive treatment cycles, and there was no difference in activity by the date of manufacturing of CQD for four weeks. Results of this study suggest that it is advantageous to use CQD synthesized from SCG under acidic conditions and VLD antimicrobial activities can be applied to the fresh produce washing process. Further research is needed on a method for synthesizing CQD that is not affected by pH conditions.-
dc.description.tableofcontentsI. INTRODUCTION 1
II. MATERIALS AND METHODS 7
2.1. Synthesis of CQD 7
2.2. Characterization 7
2.3. Bacterial culture and inoculum preparation 8
2.4. Antimicrobial effect of CQD under visible light irradiation 9
2.5. Fluorescence Quantum yield (FLQY) measurement 10
2.6. Band gap energy determination 11
2.7. Measurement of surface charge 12
2.8. CQD uptake 12
2.9. ROS scavenger 13
2.10. ROS defense enzyme 13
2.11. Measurement of intracellular ROS generation and cell membrane damage 14
2.12. Application of VLD antimicrobial activities of CQD on apple washing process 16
2.12.1. Application on apple washing produce 16
2.12.2. Reusability of VLD antimicrobial activities of CQD on apple washing process 17
2.12.3. Evaluation of changes of CQD activity with temperature and storage time 18
2.13. Statistical analysis 19

III. RESULTS AND DISCUSSIONS 20
3.1. Characterization of CQD synthesized from SCG 20
3.2. Comparison of VLD antimicrobial activities of CQD synthesized from SCG at different pH conditions 26
3.3. Change in photodynamic properties of CQD synthesized from SCG at different pH conditions 30
3.4. Effect of zeta potential change of CQD and pathogens according to pH condition on uptake of CQD into cells 38
3.5. Investigation of ROS scavenger Changes within cells at different pH conditions 42
3.6. Changes in activities of ROS defense enzymes within cells at different pH conditions 46
3.7. Changes in the degree of intracellular ROS generation and oxidative damage at different pH conditions 49
3.8. Application in washing process with VLD antimicrobial activities of CQD 55
3.9. Evaluation of reusability and activity change over time of CQD 62

IV. CONCLUSION 65
V. REFERENCES 66
VI. 국문초록 82
-
dc.format.extentXII,83-
dc.language.isoeng-
dc.publisher서울대학교 대학원-
dc.subjectCarbon quantum dot-
dc.subjectvisible-light-driven antimicrobial activity-
dc.subjectEscherichia coli O157:H7-
dc.subjectantibacterial activity-
dc.subjectinactivation mechanism-
dc.subjectfresh produce washing-
dc.subject.ddc630-
dc.titleSynthesis of carbon quantum dot from spent coffee ground exhibiting visible-light-driven antimicrobial activity against Escherichia coli O157:H7-
dc.title.alternativeSpent Coffee Ground (SCG)유래의 Carbon Quantum dot(CQD) 합성 및 광촉매 작용을 이용한 Escherichia coli O157:H7 저감화-
dc.typeThesis-
dc.typeDissertation-
dc.contributor.AlternativeAuthorJiyeong Kim-
dc.contributor.department농업생명과학대학 농생명공학부-
dc.description.degree석사-
dc.date.awarded2023-02-
dc.contributor.major식품생명공학전공-
dc.identifier.uciI804:11032-000000174749-
dc.identifier.holdings000000000049▲000000000056▲000000174749▲-
Appears in Collections:
Files in This Item:

Altmetrics

Item View & Download Count

  • mendeley

Items in S-Space are protected by copyright, with all rights reserved, unless otherwise indicated.

Share