A novel bioemulsifier produced by Exiguobacterium sp. strain N4-1P isolated from petroleum hydrocarbon contaminated coastal sediment

Abstract

In this study, Exiguobacterium N4-1P is reported as a bioemulsifier producer for the first time. The strain was found to be closely related to E. oxidotolerans strain T-2-2T, E. antarcticum B7T, and E. antarcticum B7T with similarities of 99.47, 98.70 and 98.63%, respectively. Its phenotypic properties such as metabolic fingerprints, membrane composition, and cell morphology were determined. Different carbon sources were used for bioemulsifier production and diesel was confirmed to stimulate the yield effectively. The produced bioemulsifier is a complex mainly composed of lipopeptides with C16:0 (32.18%) and C18:0 (40.99%) as the primary fatty acids. The produced bioemulsifier could form emulsions effectively with diverse hydrocarbons. No foams were formed during the production and applications, which would facilitate its commercialization. The bioemulsifier was stable over a wide range of salinity (0-25%), pH (2-12), and temperature (below 50 °C). Exiguobacterium N4-1P and the produced bioemulsifier fills knowledge gaps and has promising application potential in diverse fields, especially in environmental engineering.