title: The production and physicochemical properties of a biosurfactant mixture obtained from Sphingobacterium detergens.
abstract: The commercial application of a new biosurfactant such as the one produced by Sphingobacteriumdetergens needs a cost-effective process and knowledge of its properties. In the present study, a specific medium and a downstream process have been developed to enhance biosurfactant production. Optimal concentrations of nutrients in MCA medium were (g/L) the following: KH(2)PO(4), 1; K(2)HPO(4), 2; CO(NH(2))(2) 0.88; CaCl(2) 0.01; FeSO(4)·7H(2)O, 0.01; MgSO(4)·7H(2)O 0.5; KCl, 1.0; trace elements 0.05 mL. Biosurfactant production in the MCA medium required a bacterial co-metabolism of glucose and an n-alkane. A fed-batch culture with supernatant lyophilization prior to organic extraction produced 466 mg/L of organic extract, which represents a 6.9-fold increase in production. The newly obtained biosurfactant was a complex mixture of molecules. The three characterized fractions consisted of the complete fraction and two second-level purification fractions with apolar and polar characteristics. The complete and apolar fractions have been shown to self-aggregate in the form of lamellar liquid crystals at a high concentration and bilayers at lower concentrations. Negatively charged particles were identified, which were neutralized at a low pH with a concomitant increase in size. The pH affected the surface tension of the solutions congruently with phosphate headgroups.
authors: Laboratory of Microbiology, Fac. of Pharmacy, Univ. Barcelona, Av. Joan XXIII, 08028 Barcelona, Spain.
authors: C
authors: C
authors: Burgos-Díaz
authors: R
authors: R
authors: Pons
authors: J A
authors: JA
authors: Teruel
authors: F J
authors: FJ
authors: Aranda
authors: A
authors: A
authors: Ortiz
authors: A
authors: A
authors: Manresa
authors: A M
authors: AM
authors: Marqués
mesh_terms: D061249:Batch Cell Culture Techniques; D007218:Industrial Microbiology / Q000379:methods*; D045249:Sphingobacterium / Q000737:chemistry / Q000378:metabolism*; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D013501:Surface-Active Agents