Invited Talk: Dissecting Cocoa Beans Fermentation through Metagenomics Analysis

Cocoa cultivation in Colombia is highly relevant as Colombian cacao has unique organoleptic properties that have placed it into the category of special cocoa. One of the variables with the greatest impact is the presence and activity of the microorganisms associated with the fermentation processes, at which time most of the organoleptic properties of chocolate are acquired. Therefore, a comprehensive description of the microbial communities at the species level, associated with each day of a standardized process of fermentation, has not been reported yet. The objective of this research is to identify the species of microorganisms involved throughout a process of fermentation of fine aroma cocoa beans to produce chocolate and construct two genome-scale metabolic models (GSMMs), one for first day and other for the last one, to identify main metabolites related with this process. For this, a sample of the cocoa beans was extracted for each day during this process in a cocoa production farm. Sequencing of 16S rRNA and ITS2 was performed for the detection of bacteria and fungi by means of MiSeq Illumina. The identification allowed to describe that the dominant species are Bacillus subtilis, Lactobacillus fermentum, Saccharomyces cerevisiae, Acetobacter aceti, Fructobacillus pseudofilcunes and Halomonas stevensi. Interestingly, our study describes the presence of Pestalotiposis rhodondendri, Lysinibacillus xylanilyticus and Lactobacillus vini which had not been previously reported in cocoa beans fermentation. With GSMMs, the presence of sugars, alcohol and citric acid was register for first day and acetic acid production for the last day of fermentation process.