| Abstract | 第4-5页 |
| Chapter 1. Review of literature and objectives | 第9-26页 |
| 1. | 第9-15页 |
| 1.1 Importance of Yeasts | 第9-12页 |
| 1.2 Growth and maintenance of yeast cultures | 第12-13页 |
| 1.3 Yeast Pathogenecity | 第13-15页 |
| 2. Current classification of the yeasts | 第15-20页 |
| 2.1 Ribosomal RNA/DNA assessing phylogenetic relationships | 第18页 |
| 2.2 Phylogenetics | 第18-20页 |
| 3. Importance of Phytate and phytase | 第20-26页 |
| 3.1 Microbial phytases | 第24页 |
| 3.2 Phytase producing yeasts | 第24-26页 |
| Chapter 2. Screening of marine yeast strains from different habitats of China Sea and Indian Ocean | 第26-32页 |
| 2.1 Introduction | 第26页 |
| 2.2 Materials and methods | 第26-27页 |
| 2.2.1 Sample collection and culture media | 第26-27页 |
| 2.2.2 Phylogenetical analysis | 第27页 |
| 2.3 Results and discussion | 第27-32页 |
| Chapter 3. Screening of marine yeast strains for phytase and their phytase activity | 第32-39页 |
| 3.1 Introduction | 第32页 |
| 3.2 Materials and method | 第32-35页 |
| 3.2.1 Screening of yeasts for phytase activity | 第32-34页 |
| 3.2.2 Phytase assay | 第34-35页 |
| 3.3 Results and discussion | 第35-39页 |
| Chapter 4. Identification and classification of Phytase secreting yeast strains | 第39-59页 |
| 4.1 Introduction | 第39页 |
| 4.2 Materials and methods | 第39-43页 |
| 4.2.1 The yeast strains | 第39页 |
| 4.2.2 The morphology of cells | 第39-40页 |
| 4.2.3 Fermentation of sugars | 第40页 |
| 4.2.4 Assimilation of carbon compounds | 第40页 |
| 4.2.5 Assimilation of Nitrogen compounds | 第40-41页 |
| 4.2.6 Acid production from glucose | 第41页 |
| 4.2.7 Hydrolysis of urea | 第41页 |
| 4.2.8 Gelatin liquefaction | 第41-42页 |
| 4.2.9 185 rRNA gene sequencing and phylogenetic Analysis | 第42-43页 |
| 4.3 Results and discussion | 第43-59页 |
| 4.3.1 Morphology of Colonies and Cells | 第43-47页 |
| 4.3.2 Biochemical and physiological characteristics of ten yeast strains | 第47-49页 |
| 4.3.3 Growth on Nitrogen sources, different temperatures and other characteristics | 第49-52页 |
| 4.3.4 PCR results and genetic diversity | 第52-59页 |
| Chapter 5. Purification and properties of extra cellular phytase secreted by Hanseniaspora uvarum WZ1 | 第59-73页 |
| 5.1 Introduction | 第59-60页 |
| 5.2 Materials and methods | 第60-62页 |
| 5.2.1 Strains | 第60页 |
| 5.2.2 Medium and culture condition | 第60-61页 |
| 5.2.3 Purification of enzyme | 第61页 |
| 5.2.4 Determination of enzyme activity and total protein | 第61页 |
| 5.2.5 Gel electrophoresis | 第61-62页 |
| 5.2.6 Effects of pH and temperature on activity | 第62页 |
| 5.2.7 Effect of different salts on phytase activity | 第62页 |
| 5.2.8 Determination of Kinetic parameters | 第62页 |
| 5.3 Results and discussion | 第62-73页 |
| 5.3.1 Medium and culture condition | 第62-67页 |
| 5.3.2 Purification results and kinetic parameters | 第67-73页 |
| Overall conclusion and future prospects | 第73-76页 |
| References | 第76-87页 |
| List of publications | 第87-88页 |
| Acknowledgement | 第88-90页 |
