Biosurfactant production from Candida lipolytica in bioreactor and evaluation of its toxicity for application as a bioremediation agent

- Animal fat and corn steep liquor were used as substrate for biosurfactant production.
- The production of biosurfactant reached 40 g/l and 25 mN/m in a 50-l bioreactor.
- The cell biomass was characterized for use in animal nutrition.
- The biosurfactant was not toxic to a bivalve, a microcrustacean or vegetal seeds.
- Degradation of oil in seawater was stimulated by the biosurfactant.

This large-scale production, toxicity, characterization and economic analysis of the biosurfactant from Candida lipolytica UCP 0988 produced in the low-medium formulated with animal fat and corn steep liquor was investigated. The biosurfactant was produced in the stationary phase under 200 rpm in the absence of aeration and reduced the surface tension of the medium from 50 to 28 mN/m after 96 h, yielding 10.0 g/L of isolated biosurfactant in a 2 L bioreactor. The production was maximized in a 50 L bioreactor, reaching 40 g/L biosurfactant and 25 mN/m. The cell biomass was quantified and characterized for use in animal nutrition. Chemical structures of the biosurfactant were identified using FTIR and NMR. The crude biosurfactant was not toxic to the bivalve Anomalocardia brasiliana, to the microcrustacean Artemia salina, or three species of vegetables seeds. The biosurfactant stimulated the degradation of motor oil by the seawater indigenous microorganisms. The results obtained indicate that the biosurfactant produced has great potential to be applied as a bioremediation agent for cleaning oil spills.

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