Production of Ecofriendly Bio-dye using Microorganisms and their Applications to Biodegradable Polymers
미생물을 이용한 친환경 바이오 염료의 생산 및 생분해성 고분자로의 응용
- 주제(키워드) Poly(3-hydroxybutyrate) , indigo , indigo derivatives , deoxyviolacein , melanin
- 주제(DDC) 628
- 발행기관 아주대학교 일반대학원
- 지도교수 최권영
- 발행년도 2024
- 학위수여년월 2024. 2
- 학위명 박사
- 학과 및 전공 일반대학원 환경공학과
- 실제URI http://www.dcollection.net/handler/ajou/000000033527
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Recent advancements in biotechnology have widens the barriers that provides the opportunity develop a potential biodegradable polymers through a multifaceted approach. Encompass a wide range, including well known polymers like PHA (Poly(hydroxyalkanoate)), PLA (poly lactic acid), and PBS (poly alkylene succinate). Although these biodegradable polymers are environment friendly, they also have certain limitations. Firstly, the degradation rate of these polymers is often influenced by specific environmental conditions, making it challenging to precisely control the degradation timeline. Additionally, these polymers tend to have higher production costs and exhibit relatively modest mechanical properties, which place significant constraints on their widespread application. To overcome these challenges, efforts have been made to enhance their performance, regulate degradation, and improve their ecofriendliness through the incorporation of additives. Within the scope of my doctoral dissertation, the research has focused on the use of environmentally friendly biochemistry and the integration of microbially-derived dyes or pigments as additives to biodegradable polymers. Furthermore, these additives have been employed as functional chemicals to enhance the overall functionality and utility of the polymers. Firstly, a one-pot biosynthesis technique was employed to produce Indigo Derivatives-Incorporating Poly(3-hydroxybutyrate) (IDPs) using a modified E. coli strain. A spectrum of indigo derivatives was generated, each displaying unique physical and biological properties. These indigo derivatives were also employed as additives, providing the capability to regulate biodegradability. Each of the produced indigo derivative biodegradable films exhibited different antioxidant capacities, physical properties, and molecular weights, depending on their interaction with the PHB (polyhydroxybutyrate) polymer. This demonstrated that by modulating the indigo derivatives, it is possible to alter physiological and physical characteristics such as biodegradability, antioxidant capacity, and physical properties. Practical applications of these IDPs as coatings for cellulose were explored, resulting in various surface structures without compromising their color. Secondly, Violacein, a well-known purple dye, is produced by microorganisms like Chromobacterium violaceum. It's famous for its anti-cancer, anti-tumor, and anti-malignant properties against human cells, as well as its antibacterial, antifungal, and antimicrobial effects on various microorganisms, including bacteria and archaea. Owing to these qualities, violacein has been extensively studied and used for various purposes. Its unique color and antimicrobial properties have led to its adoption as an additive in films and polymers. A composite, designated as poly-β-hydroxybutyrate-cellulose augmented with deoxyviolacein (PHB-DVCell), was synthesized. This composite combined the properties of L-tryptophan-derived deoxyviolacein and externally sourced cellulose, revealing interesting characteristics, especially the stability of deoxyviolacein molecules within the biodegradable layers. Lastly, a breakthrough in addressing the historical issue of melanin's water-insolubility was achieved by developing an environmentally friendly melanin variant using genetically modified E. coli. This novel melanin chemical, derived from gallic acid, was successfully synthesized within genetically engineered E. coli, exhibiting superior antioxidant and antimicrobial properties when compared to conventional tyrosine-based melanin. Not only this, the new water-soluble gallic acid melanin also demonstrated enhanced thermal stability compared to traditional melanin, along with good electrical conductivity (0.136 S/cm). Overcoming one of the biggest drawbacks of conventional melanin, this novel melanin was applied in hydrogel sensors. The melanin-bound hydrogel sensors showed increased adhesiveness, enabling the detection of finger movements even on localized areas like a finger. Furthermore, leveraging the high antioxidant and antimicrobial properties of this water-soluble gallic acid melanin, it was applied to PVA films to explore its potential as food packagingmaterial. Together, these studies highlight the versatility of biodegradable polymers and their potential in biotechnological applications. Essentially, this comprehensive research promises a colorful, functional, and sustainable future in the domain of biodegradable polymers and organic pigments
more목차
Chapter I. One-pot production of indigo derivatives and PHB by co-expression in E.coli and control of physical properties of PHB 1
A. Introduction 2
B. Materials and Methods 7
1. Materials 7
2. Bacterial species and cultivation conditions 7
3. Separation and refinement of PHBs integrated with indigo derivatives from cell cultures 8
4. Measuring PHB production through Gas Chromatography analysis 9
5. Assessing the Color Variations in the Films 10
6. Assessment of ABTS(2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic Acid) Radical Scavenging Abilities 10
7. Evaluating the Biodegradability of IDP Films through the Utilization of Active Cupriavidus necator 11
8. Assessing the Average Molecular Weight of IDP Films Using Gel Permeation Chromatography (GPC) 12
9. IDPs Examination Utilizing Differential Scanning Calorimetry (DSC), Nanoindentation, and Scanning Electron Microscopy (SEM) 12
10. Analyzing IDPs through Methods: Nanoindentation and Scanning Electron Microscopy (SEM) 13
C. Results and Discussion 14
1. Procedure for integrating PHB with indigo derivatives in Escherichia coli 14
2. Generation of pigmented IDPs 17
3. Radical scavenging capacity of IDP films 18
4. Investigation of thermal characteristics and differential scanning calorimetry (DSC) examination of IDPs 21
5. Determination of the mean6 molecular weight of IDP films using gel permeation chromatography (GPC) 24
6. Influence of the integration of indigo derivatives on the degradability and colorfastness of IDPs 27
7. Nanoindentation analysis of IDPs 32
8. Comprehension of relation between properties of polymers and IDP structures 36
9. Utilization of IDP in the cellulose overlay for single-use packaging substrates examined via scanning electron microscopy 37
D. Conclusion 40
E. Summary 41
Chapter II. Application of Deoxyviolacein, a functional dye, to PHB and cellulose double layer biodegradable polymer 42
A. Introduction 43
B. Materials and Methods 46
1. Chemicals 46
2. Bacterial strains and culture conditions 46
3. Tyrosinase inhibition test 47
4. Test of Biodegradability 47
C. Results and Discussion 48
1. The synthetic pathway for generating PHB and deoxyviolacein in the E. coli system 48
2. Properties of deoxyviolacein generated through E. coli cells expressing vioABCE 51
3. The synthesis of deoxyviolacein and the fabrication of deoxyviolacein-layered PHB films 55
4. The Assessment of Antioxidant Properties in PHB-DV and PHB-DV-Cell Films 63
5. Differential Scanning Calorimetry (DSC) Examination and Thermal Characteristics of PHB-Cell, PHB-DV, and PHB-DV-Cell Films 64
6. The Impact of Introducing Deoxyviolacein on the Biodegradability of the PHB Films 65
7. FT-IR and SEM analyses were conducted to characterize the PHB films 66
D. Conclusion 70
E. Summary 71
Chapter III. Biosynthesis of melanin, a bio-pigment, in Escherichia coli, synthesis of new melanin that overcomes the disadvantages of previous melanin, and its applications 72
A. Introduction 73
B. Materials and Methods 76
1. Chemical compounds and materials 76
2. Purification of melanin 76
3. Tensile properties of thin plastic sheeting 77
C. Results and Discussion 78
1. The synthetic pathway for generating soluble Melanin in the E. coli system 78
2. Analysis of structural features of melanin 81
3. Melanin charaterization: Exploring Biological Activity and Mass Dynamics 85
4. Characterization of the electrochemical potentials of soluble Melanin 90
5. Physical and biological properties of Gallic acid melanin applications 98
D. Conclusion 112
E. Summary 113
Chapter IV. Overall conclusion 114
References 117
