A genetic approach to understanding the sensitivity and resistance of Listeria monocytogenes to rhamnolipid biosurfactants

Abstract

The growing environmental awareness of the population, combined with the requirements of legislation, encouraging industry to search for products less aggressive to health and environment. The rhamnolipids (RL) are a class of microbial surfactants which have properties of interest to the food industry not only because of their intrinsic characteristics, but also for their environmental-friendly nature, low toxicity and production from renewable resources; being currently considered important tools for innovation and sustainability. Previous work from our research group demonstrated that RL biosurfactants were able to inhibit the growth of the food pathogen L. monocytogenes. Although some attempts to elucidate the mode of action of rhamnolipids have been reported in the literature, the molecular basis of their action on the bacterial cell is not yet understood; the development of resistance and the factors relative to sensitivity of L. monocytogenes to rhamnolipids have never been studied. The objective of this project is to evaluate the antimicrobial activity of RLs using a genetic approach based on the isolation and characterization of mutants of L. monocytogenes hypersensitive or resistant to rhamnolipids. The results obtained can contribute to a better understanding of the mechanism of action of RL, in addition to providing useful information for the future industrial application of these biosurfactants. (AU)