50 research outputs found
How Can We Define Mastery? Reflections on Learning, Embodiment and Professional Identity
Men in Tights and the Multiplication of Mixed Metaphors: Comment on Brent Beal's and Heather Olson Beal's âRethinking the Market Metaphor: School Choice, the Common Good, and the National Football Leagueâ
Advances in understanding the enzymatic potential and production of ochratoxin A of filamentous fungi isolated from cocoa fermented beans
In this work, we determined the degree of filamentous fungi contamination in cocoa fermented seeds and the fungal potential to produce enzymes that could contribute to the cocoa quality. Internal transcribed spacer amplicon sequencing (ITS) showed 11 different species with Byssochlamys spectabilis, Aspergillus niger, Aspergillus flavus, Aspergillus carbonarius, Circinella muscae and Penicillium citrinum as the most abundant species. Our results evidenced intra and inter-species differences in the enzymes production. Cellulases, ÎČ-glucosidase, ornithine decarboxylase and phenylalanine decarboxylase were the most diffused enzymes expressed in the 53 strains here studied. Moreover, A. niger (6/12), A. carbonarius (2/3), and P. citrinum (3/3) showed high pectinolytic activity. Remarkable was the amino decarboxylase activity of P. citrinum, and A. flavus strains. For the first time we reported the presence of B. spectabilis in cocoa fermented beans, which could play an important role in the biogenic amines formation. In addition, we explored the capability of the Aspergillus section Nigri strains, to produce ochratoxin A (OTA) in a cacao model system (CPMS) and in malt extract medium (MEL). We observed that CPMS, but not MEL, stimulated the OTA production in 6 out 15 strains of Aspergillus section Nigri, reaching values ranging between 1.70 and 4995 ÎŒg OTA kgâ1 dry mycelium