Title Page
Contents
List of Abbreviations 11
Abstract (Korean) 12
CHAPTER 1. GENERAL INTRODUCTION 15
1.1. Microalgae 15
1.2. Byproducts from the tangerine processing industry 19
1.3. Extremophile microalgae, Galdieria Sulphuraria 21
CHAPTER 2. SELECTION OF BIOMASS & STRAINS AND OPTIMIZATION OF MEDIUM 24
2.1. Introduction 24
2.2. Material & method 27
2.2.1. Preparation of biomass and microalgae strain 27
2.2.2. Preparation of tangerine peel medium 27
2.2.3. Cultivation conditions 28
2.2.4. Measurement of cell growth 29
2.2.5. Analysis methods 29
2.3. Results and discussion 30
2.3.1. Selection of biomass 30
2.3.2. Selection of strain 32
2.4. Conclusion 36
CHAPTER 3. PHYCOCYANIN PRODUCTION OF Galdieria sulphuraria 37
3.1. Introduction 37
3.2. Material & method 40
3.2.1. Preparation biomass 40
3.2.2. Phycocyanin extraction 40
3.2.3. Measurement of cell growth 42
3.2.4. Analysis methods 42
3.3. Results and discussion 43
3.3.1. Verification of phycocyanin extraction method 43
3.3.2. Effect of glucose for phycocyanin production 47
3.3.3. Effect of initial cell density for phycocyanin production 49
3.4. Conclusion 51
CHAPTER 4. COMPARATIVE PHYCOCYANIN PRODUCTIVITY OF TANGERINE PEEL MEDIUM WITH CONVENTIONAL MEDIUM 52
4.1. Introduction 52
4.2. Material & method 55
4.2.1. Seed culture and preparation of TPM 55
4.2.2. Batch cultivation conditions 55
4.2.3. Phycocyanin extraction 56
4.2.4. Trophic transition condition 57
4.3. Results and discussion 58
4.3.1. Optimization of pH 58
4.3.2. Optimization of Ammonium concentration 60
4.3.3. Effect of seed condition for phycocyanin production 63
4.3.4. Comparison of growth profiles and PC production under different mediums 66
4.3.5. Transfer to phototrophic from the TPM 70
4.4. Conclusion 73
CHAPTER 5. CONCLUDING REMARKS 74
Bibliography 77
Abstract (English) 89
Table 1-1. Various alternative and additional nutrient sources for mixotrophic microalgal cultivation in previous studies 18
Table 1-2. The pharmacological and biological character of phycocyanins 23
Table 2-1. Chemical composition of tangerine peel extract 31
Table 2-2. Trace elements composition of ordinary medium (CM_ASU) 31
Figure 1-1. Simple schematic presentation of microalgae production for the competitiveness of the microalgae-based industry 17
Figure 2-1. Comparison of chemical properties of three different biomass 31
Figure 2-2. Cell growth and saccharide consumption profile of three different G. sulphuraria strains, growth of (a) G. sulphuraria O74G, (b) G. sulphuraria SOOS,... 34
Figure 2-3. Consumption of (a) NH₄⁺ and (b) PO₄³⁻ by G. sulphuraria 5587.1 cells in grown TPM and CMg₅. Student's t-test indicated significant changes of each ion... 35
Figure 3-1. Simple schematic presentation of phycocyanin extraction from microalgae 39
Figure 3-2. Profiles of extracted PC using (a) bead beating method, (b) freezing and thawing method, and (c) sonication method. 45
Figure 3-3. Picture of extracted PC using bead beating and sonication 46
Figure 3-4. Additional profiles of extracted PC using bead beating method from (a) dry cell condition and (b) wet cell condition. 46
Figure 3-5. Effects of glucose in conventional medium (CM_ASU) on (a) cell growth, (b) sugar consumption, (c) PC content, (d) PC yield. 48
Figure 3-6. Effects of initial cell density in conventional medium(CM) on (a) cell growth, (b) PC content, (c) PC yield, (d) PC productivity. 50
Figure 4-1. Effect of the pH of the TPM on growth of G. sulphuraria CCMEE 5587.1 cells. ANOVA indicated significant differences among the groups at day-10 (P < 0.001). 59
Figure 4-2. Effect of the pH of the TPM on HMF concentration. ANOVA indicated significant differences among the groups (P < 0.001) 59
Figure 4-3. Effects of ammonium concentrations in TPM on (a) cell growth, (b) sugar consumption, (c) ammonium consumption, (d) PC content. 62
Figure 4-4. Effects of seed culture adaptation (phototrophic vs. mixotrophic) on cell growth (a), sugar consumption (b), The maximum PSII quantum yield (Fv/Fm) (c), and PC level (d). Student's t-test indicated several significant between-group... 65
Figure 4-5. Growth (a) sugar concentration (b), PC concentration (c), and PC yield (d) for cells groups in TPM, CMg₂₁, and CM. Student's t-test indicated several significant differences between the TPM and CM groups, and between the TPM and CMg₂₁... 69
Figure 4-6. (a) Growth efficiency, (b) PC concentration efficiency, (c) PC production efficiency for cells groups in TPM+N,P, TPM, and CM_ASU. Student's t-test... 72