Antimicrobial and anti biofilm activity of essential oil of LippiagracilisSchauer on Clostridium bifermentans and fungal-containing biofilms

Abstract

In oil industry microbiologically influenced corrosion plays a key role since it costs a lot of money yearly. This kind of corrosion is mainly induced by the microbial biofilms occurring on the metal surface and their metabolites that modify the electrochemical conditions from metal-solution interface. This study focused on the evaluation of the antimicrobial activity of essential oil of Lippiagracilis Schauer over Clostridium bifermentans isolated from ballast of ship transporter of crude oil as well as against fungi occurring on microbial biofilms. Additionally,it was evaluated the influence of the essential oil on the corrosion of AISI 1020 carbon steel by electrochemical and gravimetric techniques.A minimum inhibitory concentration of the 20.0μg.L -1 was obtained for the essential oil over the C. bifermentans that was the same used for investigating the biocide activity against fungal biofilms for different contact time. Results showed that colony former unit (CFU) for fungi reduced to zero after 120 minutes exposition to the essential oil. Also, the essential oil of L. gracilis Schauer showed a quite good potential to control effectively the growth of C. bifermentans .Electrochemical polarization and gravimetry assays showed that essential oil of L . gracilis Schauer at concentration of 60µg.L -1 was efficient to inhibit the corrosion of AISI 1020 carbon steel. L . gracilis Schauer essential oil acted as a powerful biocide.