Gushing phenomenon and gene Hyd5 from Fusarium species in barley samples from Brazil

Anotace: Hydrophobins produced by the Fusarium genus and gushing phenomenon in brewing barley have been studied in many different countries. However, the presence of proteins associated with gushing in grains harvested in Brazil are still unknown. The surface active class 2 hydrophobin Hyd5 has been identified as a possible causative agent for gushing of beer. For this reason, the objective of this study was to evaluate the presence of HyD5 in isolated Fusarium strains from Brazilian barley samples, followed by gushing tests. The HyD5 gene was identified in all fungal isolates, and phylogenetic analysis exhibited four main linages. Gushing tests demonstrated that among the 21 malt samples analysed, 8 were positive considering overfoaming at the bottle opening. Levels ranged from 8 to 124 g/bottle of gushing. No correlation between phylogenetic analysis and gushing was observed when evaluated together; due to positive isolates for gushing being scattered throughout the phylogenetic tree, and all main clades containing at least one positive isolate for gushing. More research regarding hydrophobins and gushing should be carried out in the future due to the fungi isolated in Brazilian samples. These results offer excellent support to prevent industry losses and provide further understanding towards the gushing phenomenon in beer.