Transitions in Bacterial Communities Involved in the Fermentation-Based Production of Virgin Coconut Oil (Vco)
Date of Award
1-5-2023
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Biology (Standard Program)
First Advisor
Dr. rer. nat. Crisanto M. Lopez
Abstract
The Philippines is the second largest global producer of virgin coconut oil (VCO), a high value export commodity for many tropical nations. The manufacture of VCO relies on various methodologies that do not alter or adulterate its natural characteristics, preserving its health and nutraceutical benefits. Despite being one of the most utilized methods of VCO preparation, there is no metagenomic study that details the bacterial community shifts during fermentation based VCO production. The identification and abundance quantification of bacteria associated with coconut milk fermentation is useful for detecting dominant microbial genera involved in VCO production which remains largely unknown. Describing the constitutive microbial genera involved in this traditional fermentation method can serve as a preliminary basis for improving industrial practices and developing better fermentation procedures based on the identities of participating bacteria. In this study, 16S rRNA gene V3-V4 metagenomic sequencing was utilized to trace the transitions in microbial community profiles as coconut milk was fermented to release VCO in two commercial production lines. The results show that difference in the microbiome composition between the different processing steps examined in this work was mainly due to the abundance of Leuconostoc in the raw materials and its decline and transition into the lactic acid bacteria (LAB) groups Weissella, Enterococcus, Lactobacillus, Lactococcus, and Streptococcus during the latter stages of fermentation, corroborated through a randomized culture trial. A total of seventeen genera with relative abundances greater than 0.01% constitute the core microbiome of the two processing lines and account for 74% to 97% of the microbial abundance in all coconut-derived samples. Significant correlations were shown through an analysis of the Spearman’s rank between and within the microbial composition and pH at the genus level. The results of the present study show that the dynamics of VCO fermentation rely on the shifts in abundances of various members of the Lactobacillales order which vary per VCO production phase. The transitions between the LAB groups detected in the production phases are comparable to established changes of fermentative genera in many fermented foods. Several members of the core microbiome identified in this study may have potential impacts on VCO quality due to their acid and lipase metabolism, while some non-LAB genera can act as contaminants of concern in certain intermediary production steps. These findings could provide a basis for examining the specific roles of members of these genera in the adjustment and improvement of VCO production steps when performing the natural fermentation method.
Recommended Citation
Maini, Zomesh A., (2023). Transitions in Bacterial Communities Involved in the Fermentation-Based Production of Virgin Coconut Oil (Vco). Archīum.ATENEO.
https://archium.ateneo.edu/theses-dissertations/928
