Banca de DEFESA: PATRÍCIA MARIA ROCHA

Production of lipopeptides by submerged fermentation of Bacillus subtilis UFPEDA 438 and recovery by solvent extraction with and without the addition of di-(2-ethylhexyl)phosphoric acid (D2EHPA)

biosurfactants, D2EHPA, iturin, liquid-liquid extraction, surfactin.

Biosurfactants have potential applications in environmental sectors, as well as in the pharmaceutical, food, and other industries. Among the various classes of biosurfactants, lipopeptides, particularly surfactin and iturin, stand out. In the present study, kinetic parameters related to the synthesis of surfactin and iturin were evaluated, as well as the characterization of these biosurfactants produced by Bacillus subtilis UFPEDA 438. Additionally, liquid-liquid extraction assays were conducted employing a range of organic solvents (n-hexane, n-octanol, and chloroform-methanol 2:1, v/v), both with and without the addition of di-(2-ethylhexyl) phosphoric acid (D2EHPA). Maximum concentrations of surfactin and iturin were achieved at 24 hours, corresponding to 187.01 ± 0.37 mg/L and 10.80 ± 1.03 mg/L, respectively. The lipopeptides exhibited good thermal stability across a wide temperature range (20 to 100°C) and pH range (6 to 9), with a critical micelle concentration (CMC) of 18.70 mg/L. Extraction results with the addition of the complexing agent D2EHPA in combination with n-octanol (76.36%) and n-hexane (72.96%) demonstrated improved recovery efficiency of iturin. Regarding surfactin recovery, n-octanol alone provided the highest recovery rate, reaching 72.22%. These results position B. subtilis UFPEDA 438 as a promising producer of biosurfactants with superior surfactant properties, suitable for sustainable applications in multiple biotechnological sectors.