title: Characterisation, surface properties and biological activity of a biosurfactant produced from industrial waste by Candida sphaerica UCP0995 for application in the petroleum industry.
abstract: The development of less toxic, biodegradable, surfactants, such as biosurfactants, is a key strategy for acquiring environmentally friendly compounds. The aim of the present study was to employ an optimised medium containing 9% ground nut oil refinery residue and 9% corn steep liquor for the production of a biosurfactant by Candida sphaerica. Fermentation was carried out at 28 °C and 200 rpm for 144 h. Biosurfactant yield was 9 g/l. The biosurfactant reduced the surface tension of the medium to 25 mN/m, with a critical micelle concentration of 0.025%. The product demonstrated stability with regard to surface tension reduction and emulsification in a range of temperatures (5-120 °C) and pH values (2-12) as well as tolerance to high concentrations of NaCl (2-10%). Hydrophobicity tests indicate two possible insoluble substrate uptake mechanisms: direct interfacial uptake and biosurfactant-mediated transfer (cell contact with emulsified or solubilised hydrocarbons). The biosurfactant was characterised as an anionic glycolipid consisting of 70% lipids and 15% carbohydrates and demonstrated no toxicity to the microcrustacean Artemia salina or the vegetables Brassica oleracea, Solanum gilo, Lactuca sativa L. and Brassica oleracea L. The biosurfactant recovered 95% of motor oil adsorbed to a sand sample, demonstrating considerable potential for use in bioremediation processes, especially in the petroleum industry.
authors.affiliation: Centro de Ciências e Tecnologia, Universidade Católica de Pernambuco, Rua do Príncipe, n. 526, Boa Vista, CEP 50050-900, Recife, Pernambuco, Brazil.
authors.forename: Juliana M
authors.initials: JM
authors.lastname: Luna
authors.forename: Raquel D
authors.initials: RD
authors.lastname: Rufino
authors.forename: Leonie A
authors.initials: LA
authors.lastname: Sarubbo
authors.forename: Galba Maria
authors.initials: GM
authors.lastname: Campos-Takaki
mesh_terms: D000818:Animals; D001156:Artemia / Q000187:drug effects; D002175:Candida / Q000378:metabolism*; D006017:Glycolipids / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D010578:Petroleum; D012639:Seeds / Q000009:adverse effects; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry* / Q000378:metabolism* / Q000633:toxicity; D013696:Temperature
chemical_list: D006017:Glycolipids; D007220:Industrial Waste; D010578:Petroleum; D013501:Surface-Active Agents