Antibiofilm activity of LAE (ethyl lauroyl arginate) against food-borne fungi and its application in polystyrene surface coating

Several filamentous fungi species as Fusarium oxysporum or Cladosporium sp. can form biofilms by themselves or by participating in polymicrobial biofilms with bacteria. However, despite the high impact of biofilm on the food industry and the high efforts done to control biofilm produced by bacteria in the food area, there has been little study of strategies to control fungal biofilm in this area. In this study, the antibiofilm activity of the safe antimicrobial compound ethyl lauroyl arginate (LAE) was investigated against food spoilage fungi (Cladosporium cladosporioides, Aspergillus ochraceus, Penicillium italicum, Botrytis cynerea and Fusarium oxyspoum). Finally, the efficacy of a varnish-based coating incorporating LAE and coated onto polystyrene microtiter plates has been evaluated as a strategy to reduce fungal biofilm formation. The results of the 2,3-bis-(2-metoxi-4-nitro-5-sulfofenil)-2H-tetrazoilo-5-carboxanilida (XTT) assay, which measure the biofilm metabolic activity of moulds, demonstrated that LAE reduced significantly the formation of fungal biofilm at concentrations from 6 to 25 mg/L. This reduction was confirmed by the micrographs obtained by scanning electronic microscopy (SEM). In addition, LAE also showed antifungal activity against established biofilms. Particularly, it reduced their metabolic activity and viability at concentrations from 6 to 25 mg/L according to results obtained in the XTT assay and observations made by confocal laser scanning microscopy (CLSM). Finally, active coating incorporating from 2% of LAE proved to reduce significantly the biofilm formation in C. cladosporioides, B. cynerea and F. oxyspoum according to the results obtained in the XTT assay. However, the released studies indicated that the retention of LAE in the coating should be improved to prolong their activity.