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Investigation of cell wall and aggregation properties of co- evolved S.cerevisiae and C.sorokiniana
Thesis (MScAgric)--Stellenbosch University, 2022.
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| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2022
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| _version_ | 1867613910653206528 |
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| access_status_str | Open Access |
| author | Pillai, Santhuri |
| author2 | Bauer, Florian |
| author_browse | Bauer, Florian Pillai, Santhuri |
| author_facet | Bauer, Florian Pillai, Santhuri |
| author_sort | Pillai, Santhuri |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2022. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/125132 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:43:39.397Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/125132 Investigation of cell wall and aggregation properties of co- evolved S.cerevisiae and C.sorokiniana Pillai, Santhuri Bauer, Florian Rossouw, Debra Naidoo-Blassoples, Rene K. Stellenbosch University. Faculty of Agrisciences. Dept. of Viticulture and Oenology. Phenotype -- Molecular aspects Bacterial cell walls Yeast Coevolution Yeast -- Genetics Microbial aggregation UCTD Thesis (MScAgric)--Stellenbosch University, 2022. ENGLISH ABSTRACT: In the cultivation of micro-organisms, current industrial harvesting processes involve dewatering and filtration steps that are often environmentally detrimental, energy-intensive and costly. Thus, exploiting natural means of aggregation is highly relevant in the move towards more microbially- driven, “green” processes. A thorough understanding of the underlying mechanism of aggregation and the role of the cell wall would not only contribute to a more fundamental understanding of interspecies interactions but also inform microbially-driven industrial processes and contribute to these processes being applied more widely. A laboratory based experimental evolution system resulted in the generation of co-evolved isolates of Saccharomyces cerevisiae and Chlorella sorokiniana. The system was established through the reciprocal exchange of carbon and nitrogen sources that resulted in a co-operative obligate mutualism and over a short evolutionary period of 50 generations, the isolates generated from this co-culture experiment showed a range of phenotypes, including increased biomass production, improved mutualistic growth and, relevant to this study, differences in aggregation phenotypes. The aim of this study was therefore to further investigate the differences in these aggregation phenotypes, by exploring underlying cell wall changes and to further elucidate the co-aggregation mechanism of yeast and microalgae. Flocculation within yeast is well-characterised and is controlled by the FLO genes; a gene family encoding flocculins on the cell surface that are responsible for cellular adhesion phenotypes. In microalgae, studies have indicated that aggregation is largely condition dependent and involves interactions at the cell surface level. While microalgae have been shown to co-flocculate with other species of microalgae, filamentous fungi and bacteria there is little understanding of yeast- microalgae aggregation and cell surface interactions. This study clearly demonstrated strong phenotypic differences in aggregation and cell surface chemistries between evolved yeast isolates and identified isolates as potential cell wall mutants that would be good candidates for further genome sequencing. Furthermore, the study highlighted the need for further assay development to better characterise cell wall properties and aggregation, particularly for microalgae and further, the importance of molecular work to understand the process of cell wall remodelling in evolved isolates. In this study, as a means to address the existing knowledge gap with regards to a mechanistic understanding of yeast and microalgae aggregation, the cell wall properties of co-evolved isolates of Chorella sorokiniana and Saccharomyces cerevisiae were investigated. Overall, this study attempted to improve our mechanistic understanding of yeast-microalgae interactions and paves the way for further research into microbial-based aggregation technologies. AFRIKAANSE OPSOMMING:Industriële oesprosesse vir die verbouing van mikro-alge behels huidiglik ontwaterings- en filtrasiestappe wat dikwels nadelig vir die omgewing, energie-intensief en duur is. Die onwikkeling en gebruik van meer koste-effektiewe en natuurlike benaderings tot die verwydering van mikro-alge (en ander mikro-organismes) vanuit groei media is dus uiters relevant in die skuif na verbeterde bio-prosesse. 'n Deeglike begrip van die onderliggende meganisme van aggregasie en die rol van die selwand sal nie net bydra tot 'n meer fundamentele begrip van interspesie-interaksies nie, maar ook mikrobies-gedrewe industriële prosesse inlig en daartoe bydra dat hierdie prosesse wyer toegepas kan word. 'n Laboratorium-gebaseerde eksperimentele evolusiestelsel het gelei tot die generering van geëvolueerde isolate van Saccharomyces cerevisiae en Chlorella sorokiniana. Die ko-evolusie stelsel is gevestig deur die wedersydse uitruiling van koolstof- en stikstofbronne, wat gelei het tot 'n samewerkende, verpligte mutualisme. Oor 'n kort evolusionêre tydperk van 50 generasies het die isolate wat uit hierdie ko-kultuur eksperiment gegenereer is, 'n reeks fenotipes getoon, insluitend verhoogde biomassa produksie, verbeterde mutualistiese groei en, relevant tot hierdie studie, verskille in aggregasie-fenotipes. Die doel van hierdie studie was dus om die verskille in hierdie aggregasie-fenotipes verder te ondersoek, deur onderliggende selwandveranderinge te ondersoek en om die ko-aggregasiemeganisme van gis en mikroalge verder te ondersoek. Flokkulasie in gis (veral S. cerevisiae) is goed gekarakteriseer, terwyl minder bekend is oor die aggregasie meganismes van mikro-alge. Studies dui aan dat aggregasie in verskillende spesies van mikro-alge grootliks toestand-afhanklik is en dat die eienskappe van die seloppervlakvlak ʼn groot rol speel. Alhoewel daar al gewys is dat mikroalge saam flokkuleer met ander spesies van mikroalge, filamentagtige swamme en bakterieë, is daar beperkte begrip van gis-mikroalge-aggregasie en seloppervlak-interaksies. Hierdie studie het duidelik sterk fenotipiese verskille in aggregasie en seloppervlakchemie tussen geëvolueerde gisisolate gedemonstreer en spesifieke isolate as potensiële selwandmutante, wat goeie kandidate vir verdere genoomvolgordebepaling sou wees, geïdentifiseer. Verder het die studie die behoefte aan verdere toetsontwikkeling om selwandeienskappe en aggregasie van mikro-alge beter te karakteriseer, beklemtoon. Die belangrikheid van molekulêre werk om die proses van selwandhermodellering in geëvolueerde isolate te verstaan, is ook beklemtoon. Oor die algemeen het hierdie studie gepoog om ons meganistiese begrip van gis-mikroalge interaksies te verbeter en baan dit die weg vir verdere navorsing oor mikrobies-gebaseerde aggregasietegnologieë. Masters 2022-03-10T19:45:06Z 2022-04-29T12:55:22Z 2023-03-31T03:00:09Z 2022-03 Thesis http://hdl.handle.net/10019.1/125132 en_ZA Stellenbosch University xi, 92 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Phenotype -- Molecular aspects Bacterial cell walls Yeast Coevolution Yeast -- Genetics Microbial aggregation UCTD Pillai, Santhuri Investigation of cell wall and aggregation properties of co- evolved S.cerevisiae and C.sorokiniana |
| title | Investigation of cell wall and aggregation properties of co- evolved S.cerevisiae and C.sorokiniana |
| title_full | Investigation of cell wall and aggregation properties of co- evolved S.cerevisiae and C.sorokiniana |
| title_fullStr | Investigation of cell wall and aggregation properties of co- evolved S.cerevisiae and C.sorokiniana |
| title_full_unstemmed | Investigation of cell wall and aggregation properties of co- evolved S.cerevisiae and C.sorokiniana |
| title_short | Investigation of cell wall and aggregation properties of co- evolved S.cerevisiae and C.sorokiniana |
| title_sort | investigation of cell wall and aggregation properties of co evolved s cerevisiae and c sorokiniana |
| topic | Phenotype -- Molecular aspects Bacterial cell walls Yeast Coevolution Yeast -- Genetics Microbial aggregation UCTD |
| url | http://hdl.handle.net/10019.1/125132 |
| work_keys_str_mv | AT pillaisanthuri investigationofcellwallandaggregationpropertiesofcoevolvedscerevisiaeandcsorokiniana |