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Zwart, Wynand 2022-01-25T07:12:48Z 2022-01-25T07:12:48Z 2019 http://hdl.handle.net/11070/3113 A mini thesis submitted in partial fulfillment of the requirements for the Degree of Master of Science ( Microbiology) Wild olives are native to the Mediterranean area, sub-tropical and central Asia, and parts of Africa. Table olives are prepared from the raw fru it of the European or domesticated olive Olea europaea L. Hoff. Table olives are one of the lesser known fermented fruits in Namibia with naturally associated lactic acid bacteria (LAB) and yeast. These microorganisms are responsible for the development of aroma and flavour in the final olive product. The aim of this study was to document processing methods of table olive production, determine the physicochemical parameters which affect microbial growth and identify the microbial communities associated with olive fermentation in Namibian table olives using culture dependent and independent methods. Untreated table olives in Namibia are produced mostly by spontaneous fermentation . A total of 30 olive samples were collected from two different sites (Noab and Shalom) from February to October 2018. Total plate count, total phenolic content, total LAB and total yeast and mould count were also determined over 5 months to study the kinetics and dynamics of microbial populations during this fermentation. DNA was extracted using a culture dependent method and the culture independent method of metagenomic analysis was also used. Total phenol content ranged from 2.323 x 10-4 g Gallic Acid Equivalent (GAE) /mL at day 0 to 8.691 x 10-4 GAE/mL on day 150. Olive samples had an alkaline pH (8 .9) which was then decreased and stabilized to around 4.5 after day 30 and remained constant up until day 150. Titratable acidity ranged from 0.29 g/L at day 0 to 2.85 g/L at day 150, and combined ac idity from 0.008 Mol NaOH/L at day 0 to 0.128 Mol NaOH/L at day 150. NaCI content of both sites ranged from 8.24 to 10.54% NaCl. Total count plate showed that LAB (3.9814 ± 0.25494 log10 CFU/ mL) and yeast (4.1098 ± 0.23534 log1o CFU/ mL) had similar counts for both sites. Phyla including Rozellomycota, Chytridiomycota, Mucoromycota, Cercozoa, Rotifera, Glomeromycota, Calcarisporiellomycota, Mortierellomycota, Basidiomycota, Ascomycota, Neocallimastigomycota, Fusabacteria, Acidobacteria, Chlorojlexi, Deferribacteres, Verrucomicrobia, Actinobacteria, Bacteriodetes, Proteobacteria, Firmicutes and Cyanobacteria for 16S sRNA, 18S rRNA and ITS were identified through metagenomic analysis. This study is the first attempt to use metagenomics analysis on Namibian table olives and confirming the presence of probiotic LAB and yeast which might be responsible for the special organoleptic properties of this product. en University of Namibia Physicochemical assessment of microbial communities of fermented olives in Namibia using culture dependent and independent methods Thesisopen.access