Biosurfactants produced by Serratia species: Classification, biosynthesis, production and application

Biosurfactants are surface-active molecules that are synthesised non-ribosomally by a wide range of microorganisms including bacteria, yeast and filamentous fungi. The bacterial genus Serratia is gaining international interest, as biosurfactants produced by this genus have emerged as a promising source of antimicrobial, antifouling and antitumour compounds that possess emulsification and surface activity. Various species of Serratia have been identified as biosurfactant producers, including Serratia marcescens, Serratia rubidaea and Serratia surfactantfaciens. Members of the Serratia genus have been reported to principally produce two classes of biosurfactants, namely lipopeptides and glycolipids. Lipopeptides produced by Serratia species include serrawettins and stephensiolides, while identified glycolipids include rubiwettins and rhamnolipids. This review will primarily focus on the classification of biosurfactants produced by Serratia species and the genes and mechanisms involved in the biosynthesis of these biosurfactant compounds. Thereafter, an indication of the primary growth conditions and nutrient composition required for the optimum production of biosurfactants by this genus will be outlined. An overview of the latest advances and potential applications of the biosurfactants produced by Serratia in the medical, pharmaceutical, agricultural and petroleum industries is also provided.