Filamentous fungi diversity in the natural fermentation of Amazonian cocoa beans and the microbial enzyme activities

Abstract

Purpose The purpose of this study was to investigate the diversity of filamentous fungi and the hydrolytic potential of their enzymes for a future understanding of the influence of these factors on the sensory characteristics of the cocoa beans used to obtain chocolate. Methods Filamentous fungi were isolated from the natural cocoa fermentation boxes in the municipality of Tucuman, Pará, Brazil, and evaluated for the potential production of amylases, cellulases, pectinases, and xylanases. The fermentation was monitored by analyzing the pH and temperature. The strains were identified by sequencing the ITS1/ITS4 section of the 5.8S rDNA and partially sequencing the 18S and 28S regions, and the molecular identification was confirmed by phylogenetic reconstruction. Result The fungi isolated were comprised of three classes from the Ascomycota phylum and one class from the Basidiomycota phylum. There were found 19 different species, of this amount 16 had never been previously reported in cocoa fermentation. This fact characterizes the fermentation occurring in this municipality as having wide fungal diversity. Most of the strains isolated had the ability to secrete enzymes of interest. Cladosporium cladosporioides, Fomitopsis subtropical, Aspergillus versicolor, Penicillium pimiteouiense, Phanerochaete australis, Neonothopanus nambi, and Aspergillus parasiticus were the strains that excelled in the secretion of the following enzymes: amylase, pectinase, cellulase, and xylanase. Conclusion The presence of 16 species not yet reported in cocoa seed fermentations and their potential hydrolytic activities show a diversity of filamentous fungi in this microbial biome that needs to be better understood.

The microbiota diversity identified during the cocoa fermentation and the benefits of the starter cultures use: an overview

“…There is a strong correlation between the presence of filamentous fungi and the production of enzymes favourable to the fermentation of cocoa beans. One of the identified species and which presented a good activity in the production of amylases and pectinases, thus contributing to a good conduction in the microbial succession, as well as formation of precursors of aroma and chocolate flavour through the Maillard reaction in the roasting stage (Araújo et al ., 2019).…”

“…Three most reported groups of microorganisms gain prominence during cocoa fermentation, among which they exert influence during the process: yeasts, lactic acid bacteria (LAB) and acetic acid bacteria (AAB), and more recently, the participation of filamentous fungi is increasingly being studied. It is known that some species of filamentous fungi are natural producers of hydrolases that can corroborate in the fermentation stage (Araújo et al ., 2019).…”

Profile of Volatile Compounds of On-Farm Fermented and Dried Cocoa Beans Inoculated with Saccharomyces cerevisiae KY794742 and Pichia kudriavzevii KY794725

“…Several studies in the literature report the performance of a wide variety of yeasts, lactic and acetic bacteria during fermentation in different locations around the world [ 7 , 8 ]; however, in the Amazon, these studies are still scarce and few studies see reporting the cacao fermentative microbiota [ 9 , 10 , 11 ].…”

Understanding the Biosynthetic Changes that Give Origin to the Distinctive Flavor of Sotol: Microbial Identification and Analysis of the Volatile Metabolites Profiles During Sotol (Dasylirion sp.) Must Fermentation

“…These fermentations show the production of exoglucanase, B-xylosidase, endoglucanase, and manganese peroxidase [ 43 ]. The hydrolytic capacity of filamentous fungi enzymes to enhance sensory characteristics has been studied, showing significant levels of enzymes (xylanase, cellulose, amylase, and pectinase) produced by Aspergillus versicolor strains [ 44 ], whereas Aspergillus flavus strains are important inulinase production microorganisms [ 45 ]. Furthermore, these strains exhibit the ability to produce ascorbic acid, a metabolite that can improve the growth of other cultures during consortium fermentations [ 46 ].…”