Functional Biodiversity of Yeasts Isolated from Colombian Fermented and Dry Cocoa Beans

Abstract

Yeasts play an important role in the cocoa fermentation process. Although the most relevant function is the degradation of sugars and the production of ethanol, there is little understanding of the enzyme activities and attributes that allow them to survive even after drying. The present study explored the functional biodiversity of yeasts associated with Criollo Colombian cocoa fermented beans, able to survive after drying. Twelve species belonging to 10 genera of osmo-, acid-, thermo-, and desiccation-tolerant yeasts were isolated and identified from fermented and dry cocoa beans, with Pichia kudriavzevii and Saccharomyces cerevisiae standing out as the most frequent. For the first time, we reported the presence of Zygosaccharomyces bisporus in cocoa fermented beans. It was found that resistance to desiccation is related to the different degradation capacities of fermentation substrates, which suggests that associative relationships may exist between the different yeast species and their degradation products. Besides, the increased thermotolerance of some species was related to the presence of polyphenols in the medium, which might play a fundamental role in shaping the microbial community composition.

Pod storage time and spontaneous fermentation treatments and their impact on the generation of cocoa flavour precursor compounds

“…Saccharomyces cerevisiae and Wickerhamomyces anomalus were occasionally isolated from fermentation carried out in WB and PB, respectively. Our results are similar to those obtained by several authors that reported most isolated yeasts species belonging to several genus such as Pichia, Candida, Saccharomyces, Saccharomycopsis, Schizosaccharomyces, Wickerhamomyces and Cryptococcus involved in the cocoa fermentation (Mota-Gutierrez et al, 2018;Delgado-Ospina et al, 2020). The relationship between specific yeast strains and the cocoa fermentation treatment could be explained by the dynamics and interactions between yeasts and bacteria strongly depending on the method (Mota-Gutierez et al, 2018).…”

Bioactive compounds and techno-functional properties of high-fiber co-products of the cacao agro-industrial chain

“…The drying treatments on the fibers are consistent with the low moisture content and water activity found, which can mean a low probability of proliferation of microorganisms that deteriorate the fibers. The pH found in the fibers is slightly acidic, in CS due to traces of organic acids originated during the fermentation and drying process of the beans [ 51 ], and in CPHF due to the ripening process. The effect of the treatments on CPH showed a significant decrease (P < 0.05) in pH ( Table 1 ).…”

Exploring the Capability of Yeasts Isolated from Colombian Fermented Cocoa Beans to Form and Degrade Biogenic Amines in a Lab-Scale Model System for Cocoa Fermentation

“…For this, we selected the strains P. kudriavzevii ECA33 and S. cerevisiae 4, which did not show decarboxylase activity of the amino acids tested individually in this study. These strains were characterized previously by their good thermotolerance, as well as a strong pectinolytic and β-glucosidase activity in a synthetic medium [ 18 ] suggesting that they may have an important impact on cocoa production.…”

“…Hence, the maximum of lactic and acetic acid production was reached at 24 °C for SCB samples and at 48 h (lactic acid) and 72 h (acetic acid) for PKB samples. On the other hand, P. kudriavzevii ECA33 that is more thermotolerant than S. cerevisiae 4 [ 18 ], promoted a major accumulation of both lactic (19.7 ± 0.9 mg/kg) and acetic acid (71.5 ± 3.6 mg/kg), with respect to SCB and CB samples, at the end of the fermentation period.…”

“…asahii (3), Wickerhamomyces anomalus (6), and Zygosaccharomyces bisporus (2). These strains belonging to the culture collection of the Faculty of Bioscience and Technology for Food, Agriculture and Environment of the University of Teramo, Italy, were previously isolated from Colombian cocoa beans and identified by molecular methods [ 18 ].…”