Chemical characterization and surface properties of a new bioemulsifier produced by Pedobacter sp. strain MCC-Z

A novel biopolymer was described in the form of an extracellular polysaccharide (EPS) by Pedobacter sp.strain MCC-Z, a member of a bacterial genus not previously described as an emulsifier producer. Thenew biomolecule was extracted, purified and characterized, and its surface and emulsifying propertieswere evaluated. The purified bioemulsifier, named Pdb-Z, showed high emulsifying activity (E24% = 64%)and reduced the surface tension of water up to 41 mN/m with a critical micelle concentration value of2.6 mg/mL. The chemical characterization of Pdb-Z was performed using1H NMR, FT-IR, HPLC/MS/MS andGC/MS. Pdb-Z was found to contain 67% of carbohydrates, consisting mainly of galactose and minor quan-tities of talose, 30% of lipids, being pentadecanoic acid the major lipidic constituent, and 3% of proteins. Thebioemulsifier was a glycolipids-protein complex with an estimated molecular mass of 106Da. Further-more, Pdb-Z emulsified pure aliphatic and aromatic hydrocarbons as well as diesel more efficiently thancommercial synthetic surfactants, used for comparison. Our results suggest Pdb-Z has interesting prop-erties for applications in remediation of hydrocarbon-contaminated environments and bioremediation processes.