The impact of fermentation process on bee pollen antibacterial and antifungal activity

Abstract

Bee pollen is one of the most appreciated and oldest natural products, which chemical composition represents as a source of bioactive compounds that could be used in food industry or medicine [1]. In recent years, biologically active substances of natural origin focused a great interest of fermentation bioprocesses, which have persisted a main possibility in assay to increase a chemical variety or quantity [2]. Most of the bee pollen properties are influenced by considerable amount of phenolic compounds, mainly flavonoids, which is considered as the main reason for its antimicrobial properties [1]. The aim of this research was to determine the effect of fermentation process of bee pollen on its antibacterial and antifungal activity. Previous study shows, that solid-state fermentation of bee pollen increases total flavonoid content [3]. To our knowledge, this is the first study about the evaluation of antibacterial and antifungal activities of fermented bee pollen. Five samples of bee pollen were fermented with L. rhamnosus and L. lactis bacteria for 12 days. Spontaneous fermentation was also performed at the same conditions. Methanolic extracts of fermented and non-fermented bee pollen samples have been tested for antimicrobial activity. The antibacterial activity of bee pollen extracts was evaluated by well diffusion assay against Escherichia coli, Staphylococcus aureus and Micrococcus luteus. The results were expressed as μg of gentamicin equivalent (GEN) per millilitre of extract. The antifungal activity against mould species, namely Penicillium roqueforti and Penicillium camemberti, was also evaluated; results expressed in mm of clear zone radius around the well. The positive effect on antibacterial and antifungal activity of solid-state fermentation was revealed. Antibacterial activity of non-fermented bee pollen samples against M. luteus ranged from 13.46 ± 0.29 μg/ml (GEN) to 27.89 ± 0.29 μg/ml (GEN), [...]