Bacterial diversity and characterization of novel bacterial species from tidal and salt flats of Yongyu-do
용유도 갯벌에서의 세균 종 다양성 분석 및 신종 세균 보고
- 주제(키워드) Bacteria , Microbiology , Bacterial diversity
- 발행기관 고려대학교 대학원
- 지도교수 김재진
- 발행년도 2020
- 학위수여년월 2020. 2
- 학위구분 석사
- 학과 대학원 환경생태공학과
- 세부전공 생물재료공학
- 원문페이지 76 p
- UCI I804:11009-000000127487
- DOI 10.23186/korea.000000127487.11009.0000943
- 본문언어 영어
- 제출원본 000046051917
초록/요약
Microorganisms are the oldest living things on Earth, with bacteria having appeared four billion years ago. As bacteria have evolved and adapted to the constantly changing environment, they have become ubiquitous and can exist in a wide variety of habitats. Many bacteria are found in aquatic and terrestrial environments, as well as at high salinity, low temperatures, high temperatures, and various pH. Thus, bacteria present in various habitats have a unique metabolic capacity to survive in the environment, and these metabolites serve as important resources for biotechnological applications. However, bacteria that would prove useful in the field of biotechnology should first be culturable in a laboratory. Currently, more than 90% of bacteria cannot be cultivated by traditional laboratory culture methods, and thus, many microbial resources are still not developed. Therefore, it is necessary to isolate culturable bacteria and collect the resources in a sustainable manner. Tidal flats not only have high biodiversity as transitional areas of terrestrial and marine environments, but they also reduce the pollution of inland and coastal ecosystems by decomposing pollutants caused by human activities. Tidal flat microorganisms are known to have unique metabolic and physiological abilities to adapt to various environments, and the presence of nutrients and minerals from the ocean enables the distribution of specific microbial communities such as halophilic and halotolerant bacteria. In the past, Yongyu-do was an independent island with tidal flats and solar salterns; however, presently, Yongyu-do is joined to Yeongjong-do as land was reclaimed from the sea for constructing the Incheon International Airport. Therefore, the area does not only have a tidal flat environment but also an environmental factor that has been used to solar saltern in the past. In this study, the diversity of bacterial communities in tidal flats and salt flats was investigated through 16S rRNA gene sequencing, and novel bacteria were identified and classified through polyphasic classification. A total of 86 strains were isolated from the study area in Yongyu-do, with 67 of those from the tidal flats and 19 from the salt flats. In the salt flats, there were few species of bacteria that were relatively isolated from tidal flats, but on the other hand, only specific bacteria, such as halophiles or new species, were isolated. Among these strains, YJ-T1-11T and YJ-S3-2T, which appear to be novel species, were identified as Gemmobacter lutimaris sp. nov. and Marinobacter halodurans sp. nov. using the multiphase approach and genetic, morphological, and biochemical classification methods.
more목차
Abstract i
국문요약문 iii
LIST OF FIGURES AND TABLE viii
Chapter 1. General Introduction 1
1.1. Bacteria on Earth 2
1.2. Characteristics of coastal wetlands 3
1.3. Molecular methods for understanding the diversity of bacteria 4
1.4. Systematic approach for discovering novel bacteria 5
1.5. Objectives of this study 6
1.6. References 7
Chapter 2. Bacterial diversity from tidal and salt flats of Yongyu-do 9
2.1. Introduction 10
2.2. Materials and methods 13
2.2.1. Study sites and sediment sampling 13
2.2.2. Isolation of bacterial strains 14
2.2.3. DNA extraction and identification of isolates 15
2.2.4. Halotolerance test of bacterial strains 16
2.3. Results and Discussion 17
2.4. Conclusions 23
2.5. References 24
2.6. Supplementary tables 26
Chapter 3. Two novel bacterial species from the coastal sediments of Yongyu-do 32
3.1. Introduction 33
3.2 Materials and Methods 35
3.2.1. Bacterial isolation from tidal and salt sediment 35
3.2.2. 16S rRNA gene sequence analysis 35
3.2.3. Phylogenetic analysis 36
3.2.4. Phenotype taxonomy 37
3.2.5. Chemotaxonomy of bacterial isolates 37
3.3. Results and discussion 39
3.3.1. Isolation of bacteria from coastal sediment 39
3.3.2. Phylogenetic analysis 40
3.4. Description 50
3.4.1. Gemmobacter lutimaris sp. nov. 50
3.4.2. Marinobacter halodurans sp. nov. 52
3.5. Conclusions 54
3.6. Acknowledgement 55
3.7. References 56
Chapter 4. General conclusions 60
