Determination of fungal community diversity in fresh and traditional Chinese fermented pepper by pyrosequencing

Abstract

Fermented pepper is one of the traditional Chinese fermented vegetables. The production mainly relies on the fermentation by natural microorganisms. This fermentation system is a unique and dynamic microecological environment, and involved microbial communities are very complex. In this study, 454 pyrosequencing was first used to investigate the fungal communities in fresh pepper and different fermentation phases. The results showed that fungal communities in fresh pepper (sample M_0) were more abundant than later fermented phases. Taxa in proportions >0.01% could be assigned to 21 different genera. Taxa in proportions >1% were Trichosporon 24.11%, Rhodotorula 7.4%, Cladosporium 4.26%, Debarvomvces 3.94%, Mucor 2.51% and Cryptococcus 1.86%. There were a large number of unknown fungi (47.99%) in the sample waiting to be identified. Along with the fermentation, microbial communities became less diverse. Hanseniaspora and Pichia became the dominant fungal genera, while Trichosporon decreased from a maximum 24.11% to a minimum 0.1%. On the seventh fermentation day, the percentage of Hanseniaspora reached 89.3%. On the 20th fermentation day, taxa in proportions >1% were Hanseniaspora 69.25%, Unclassified 12.23%, Pichia 8.95%, Debaryomyces 6.22% and Rhodotorula 1.31%.