Biodiversidade bacteriana durante a fermentação espontânea de frutos de açaí (Euterpe oleracea)

Abstract

Açai (Euterpe oleracea) fruits (AF) and a wide variety of products derived from this fruit are an example of success of a local and typically Brazilian product on the global market. The AF suffer spontaneous fermentation during postharvest due mainly to its high microbial load and the favourable intrinsic and extrinsic parameters. The biodiversity of microbial community in AF and their evolution between three geographical origins and two fermentation conditions were examined. Culture-independent methods based on 16S rRNA from fifteen samples revealed that Proteobacteria, Firmicutes, Actinobacteria, Bacteroidetes and Acidobacteria were the most abundant phyla. At genus level, were identified Massilia (taxon with more than 50 % of sequences remaining constant during the 30 h of fermentation), Pantoea (taxon with the highest increase during fermentation), Naxibacter, Enterobacter, Raoultella and Klebsiella, forming the carposphere bacterial microbiota of AF. Attributes related to plant growth promotion (siderophores) and others compounds e.g. poly-3-hydroxybutyrate (PHB) and violacein in response to stress conditions could improve the Massilia preponderance. Beta diversity showed that quality parameters of AF (pH, soluble solids, titratable acididy and lipids) and elemental analysis (C, N, H and C/N ratio) were unable to establish microbial patterns in AF. This research offers new insights and perspectives of the indigenous bacterial community composition on AF as a function of spontaneous fermentation during postharvest.