Bacterial diversity of Cabernet Sauvignon must from different locations and the dynamics during wine fermentation

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dc.contributor.advisorSetati, Mathabatha Evodiaen_ZA
dc.contributor.advisorDu Plessis, Heinrichen_ZA
dc.contributor.authorMathidza, Billen_ZA
dc.contributor.otherStellenbosch University. Faculty of AgriSciences. Dept. of Viticulture and Oenology.en_ZA
dc.date.accessioned2022-03-10T18:20:34Z
dc.date.accessioned2022-04-29T09:33:43Z
dc.date.available2022-03-10T18:20:34Z
dc.date.available2022-04-29T09:33:43Z
dc.date.issued2022-04
dc.descriptionThesis (MScAgric)--Stellenbosch University, 2022.en_ZA
dc.description.abstractENGLISH ABSTRACT: Wine grapes harbour a microbiota that drives wine fermentations that may contribute to the chemical fingerprint of finished wines. The bacterial communities on grapes, in particular lactic acid bacteria (LAB) conduct malolactic fermentation (MLF), which modifies the acidity, flavour and microbial stability of wine. This study aimed to investigate the bacterial diversity on Vitis vinifera L. cv Cabernet Sauvignon in three vineyards (VIN-A, VIN-B and VIN-C), situated in different areas of the Stellenbosch wine district during 2019 and 2020 vintages. The Automated Ribosomal Intergenic Spacer Analysis (ARISA) was used to evaluate the community fingerprint of grape must. Bacterial population dynamics and diversity were determined in grape must and throughout the wine fermentation by cultivating bacteria on nutrient media and using Polymerase Chain Reaction and sequence analysis of the 16S region. Followed by the characterisation of a selection of Lactiplantibacillus plantarum and Oenococcus oeni isolates from the 2019 and 2020 vintages, which were subjected to Random Amplified Polymorphic DNA (RAPD) typing to generate genetic profiles, which were compared to determine their recurrence in the various vineyards. Chemical composition (pH, malic acid and sugar) of the grape must from each vineyard were different for both vintages. The fermentations differed between the vineyards, the wines from VIN- A was able to complete the MLF in 2019, while other vineyards presented stuck MLF. Using ARISA, 117 and 116 peaks were detected in 2019 and 2020, respectively. Each peak was considered as an operational taxonomic unit (OTU). The data showed some overlap of the OTUs in grape must from different vineyards. Thirteen bacterial OTUs in 2019 and 8 peaks in 2020 were detected in all three vineyards, whereas the majority of the OTUs were vineyard specific. Analysis of similarities (ANOSIM) of the OTU data showed notable differences in the bacterial communities between vintages. The viable counts of the grape must differed between the vintages. In 2019, the total bacterial population density in grape must ranged between 103 and 105 colony forming units per millilitres (CFU/mL), while in 2020, the bacterial population density ranged between 103 and 104 CFU/mL. A total of 360 bacterial isolates including both LAB and acetic acid bacteria (AAB) were obtained from grape must and different stages of fermentation from all vineyards during both vintages. The bacterial diversity differed between the vineyards and over the vintages. Five bacterial species were detected in grape must from VIN-B and VIN-C and 3 species in VIN-A in 2019, whereas 2020 presented higher bacterial diversity and 6, 11 and 6 different species were identified in VIN- A, VIN-B and VIN-C respectively. L. plantarum was found in grape must from all vineyards, accounting for more than 50% of the total population. O. oeni was detected in grape must of both 2019 and 2020 vintages from VIN-B and VIN-C, where it accounted for 4% of the total population in 2019. In general, the overlap of common species such as Apilactobacillus kunkeei and Acetobacter malorum was observed in wine from different vineyards. Minor unique species were isolated and clearly differed between the three vineyards. In addition, L. plantarum ISP20_9 and O. oeni ISO20_1 were the only isolates that were recurring in both 2019 and 2020 vintages. The L. plantarum and O. oeni strains showed different patterns of malic acid degradation within 7 days, indicating strain differences.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Wyndruiwe huisves mikrobes wat die alkoholiese fermentasie dryf en bydra tot die chemiese profiel van die finale wyne. Die bakteriese gemeenskap op druiwe, veral melksuurbakterieë (MSB) voer appelmelksuurgisting (AMG) uit wat die suurheid, geur en mikrobiese stabiliteit van wyn kan modifiseer. Die doel van hierdie studie was om die bakteriese diversiteit op Vitis vinifera L. cv Cabernet Sauvignon, in drie wingerde (VIN-A, VIN-B and VIN-C) wat in verskillende areas van die Stellenbosch Wyndistrik geleë is, te ondersoek tydens die 2019 and 2020 oesjare. Outomatiese Ribosomale Intergeniese Spasieerder Analise (ORISA) was gebruik om die vingerafdruk van die mikrobiese gemeenskap van die druiwemos te genereer. Die bakteriese populasie dinamika en diversiteit van druiwemos en tydens fermentasie was ondersoek, deur die kultivering van bakterieë op voedingsmedia en die gebruik van die Polimerase kettingreaksie (PKR) in kombinasie met volgorde analise van die 16S streek. Dit was opgevolg deur die karakterisering van ‘n seleksie van Lactiplantibacillus plantarum and Oenococcus oeni isolate van 2019 en 2020 deur gebruik te maak Ewekansig Geamplifiseerde Polimorfiese DNA (EGPD) om die genetiese profiele op rasvlak te onderskei. Hierdie profiele was gebruik om te bepaal watter rasse herhaaldelik in die verskeie wingerde voorgekom het. Die chemiese samestelling (pH, appelsuur en suiker) van die druiwemos van elke kelder het verskil vir beide oesjare. Die fermentasies het verskil tussen wingerde en die wyne van VIN-A kon AMG suksesvol in 2019, maar die wyne van die ander wingerde kon nie. Een honderd en sewentien en 116 pieke kon respektiewelik in 2019 en 2020, onderskei word deur ORISA te gebruik. Elke piek was as ‘n operasionele taksonomiese eenheid (OTE) beskou. Die data het gewys dat daar oorvleueling tussen die OTEs van die druiwemos van die verskillende wingerde was. Dertien bakteriese OTEs in 2019 en 8 pieke in 2020 was waargeneem in al drie wingerde, maar die meerderheid van die OTEs was wingerd spesifiek. Ontleding van ooreenkomste van die OTE data het gewys dat daar noemenswaardige verskille in die bakteriese gemeenskappe tussen oesjare was. Die lewensvatbare tellings van die bakterieë in die druiwemos het verskil tussen die oesjare. In 2019, het die totale bakteriese populasie gewissel tussen 103 and 105 kolonievormende eenhede per milliliter (KVE/mL), terwyl dit in 2020, gevarieer het tussen 103 and 104 KVE/mL. Drie honderd en dertig bakteriese isolate, insluitende MSB en asynsuurbakterieë (ASB), was uit druiwemos en tydens die verskillende stadiums van fermentasie geïsoleer van al die wingerde en oor beide oesjare. Die bakteriese diversiteit het verskil tussen die wingerde en tussen die oesjare. Vyf bakteriese spesies was waargeneem in druiwemos VIN-B en VIN-C, maar slegs 3 spesies in druiwemos van VIN-A in 2019. In 2020, was meer bakteriese diversiteit waargeneem en 6, 11 en 6 verskillende spesies was geïdentifiseer in druiwemos van VIN-A, VIN-B en VIN-C, respektiewelik. L. plantarum was teenwoordig in druiwemos van al die wingerde en het bygedra tot 50% van die totale populasie. O. oeni was teenwoordig in druiwemos van VIN-B en VIN-C in 2019 en 2020, waar dit 4% van die totale populasie in 2019 verteenwoordig het. Die oorvleueling van gemeenskaplike spesies soos Apilactobacillus kunkeei en Acetobacter malorum was waargeneem in wyne van die verskillende wingerde. Unieke spesies wat teen lae persentasies voorgekom het, het ook duidelik verskil tussen die drie wingerde. L. plantarum ISP20_9 en O. oeni ISO20_1 was die enigste isolate wat herhalend voorgekom het gedurende die 2019 en 2020 oesjare. Die L. plantarum and O. oeni rasse het verskillende appelsuur afbraak patrone gewys, wat ‘n aanduiding is van rasverskille.af_ZA
dc.description.versionMastersen_ZA
dc.format.extent76 pages : illustrations (some color)en_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/124798
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subjectSpontaneous fermentationen_ZA
dc.subjectOenococcus oenien_ZA
dc.subjectLactiplantibacillus spp.en_ZA
dc.subjectMalolactic fermentationen_ZA
dc.subjectCabernet Sauvignonen_ZA
dc.subjectBacterial diversity -- Genetic aspectsen_ZA
dc.subjectWine and wine making -- Chemistryen_ZA
dc.subjectUCTDen_ZA
dc.titleBacterial diversity of Cabernet Sauvignon must from different locations and the dynamics during wine fermentationen_ZA
dc.typeThesisen_ZA
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