title: Environmental fate, toxicity, characteristics and potential applications of novel bioemulsifiers produced by Variovorax paradoxus 7bCT5.
abstract: The aims of this work were the characterisation and the evaluation of potential environmental applications of the bioemulsifiers produced by Variovorax paradoxus 7bCT5. V. paradoxus 7bCT5 produces a mixture of high molecular weight polysaccharides. The extracellular bioemulsifiers were able to produce a thick stable oil/water emulsion and maintained the emulsification activity after boiling and at low temperatures. Environmental behavior and impact of bioemulsifiers release were assessed by evaluating biodegradability, toxicity and soil sorption. Respirometric tests showed that moderate biodegradability occurred by soil bacterial inoculum. Furthermore, the produced compounds did not show any toxic properties through different ecotoxicological tests. The K(d) values ranged from 1.3 to 7.3 L/kg indicating a high sorption affinity of the bioemulsifier molecules to soil particles. The soil sorption affinity likely affected the bioemulsifier ability to remove hydrocarbons from contaminated soils. In fact, V. paradoxus 7bCT5 bioemulsifiers significantly increased the removal of crude-oil from sandy soil compared to water.
authors.affiliation: Department of Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milano, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Franzetti
authors.forename: Isabella
authors.initials: I
authors.lastname: Gandolfi
authors.forename: Chiara
authors.initials: C
authors.lastname: Raimondi
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Bestetti
authors.forename: Ibrahim M
authors.initials: IM
authors.lastname: Banat
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Smyth
authors.forename: Maddalena
authors.initials: M
authors.lastname: Papacchini
authors.forename: Massimo
authors.initials: M
authors.lastname: Cavallo
authors.forename: Letizia
authors.initials: L
authors.lastname: Fracchia
mesh_terms: D000327:Adsorption; D001673:Biodegradation, Environmental; D042621:Comamonadaceae / Q000737:chemistry*; D045703:Emulsifying Agents / Q000378:metabolism* / Q000633:toxicity*; D007218:Industrial Microbiology / Q000379:methods*; D010578:Petroleum / Q000378:metabolism; D012989:Soil Pollutants / Q000378:metabolism*; D018675:Toxicity Tests
chemical_list: D045703:Emulsifying Agents; D010578:Petroleum; D012989:Soil Pollutants