title: Aquatic toxicity and biodegradability of a surfactant produced by Bacillus subtilis ICA56.
abstract: In this work, the environmental compatibility of a biosurfactant produced by a Bacillus subtilis strain isolated from the soil of a Brazilian mangrove was investigated. The biosurfactant, identified as surfactin, is able to reduce surface tension (ST) to 31.5 ± 0.1 mN m-1and exhibits a lowcritical micelle concentration (CMC) value (0.015 ± 0.003 g L-1). The highest crude biosurfactant concentration (224.3 ± 1.9 mg L-1) was reached at 72 h of fermentation. Acute toxicity tests, carried out with Daphnia magna, Vibrio fischeri and Selenastrum capricornutum indicated that the toxicity of the biosurfactant is lower than that of its chemically derived counterparts. The results of the biodegradability tests demonstrated that the crude surfactin extract was degraded by both Pseudomonas putida and a mixed population from a sewage-treatment plant, in both cases the biodegradation efficiency being dependent on the initial concentration of the biosurfactant. Finally, as the biodegradation percentages obtained fall within the acceptance limits established by the Organization for Economic Co-operation and Development (Guidelines for Testing of Chemicals, OECD 301E), crude surfactin can be classified as a "readily" biodegradable compound.
authors: a Departamento de Engenharia Química , Universidade Federal do Ceará , Fortaleza , CE , Brazil.
authors: Darlane W F
authors: DW
authors: De Oliveira
authors: b Department of Chemical Engineering , Faculty of Sciences, University of Granada , Granada , Spain.
authors: Alejandro B
authors: AB
authors: Cara
authors: b Department of Chemical Engineering , Faculty of Sciences, University of Granada , Granada , Spain.
authors: Manuela
authors: M
authors: Lechuga-Villena
authors: b Department of Chemical Engineering , Faculty of Sciences, University of Granada , Granada , Spain.
authors: Miguel
authors: M
authors: García-Román
authors: c Departamento de Biologia , LemBiotech, Laboratório de Ecologia Microbiana e Biotecnologia, Universidade Federal do Ceará , Fortaleza , CE , Brazil.
authors: Vania M M
authors: VM
authors: Melo
authors: a Departamento de Engenharia Química , Universidade Federal do Ceará , Fortaleza , CE , Brazil.
authors: Luciana R B
authors: LR
authors: Gonçalves
authors: b Department of Chemical Engineering , Faculty of Sciences, University of Granada , Granada , Spain.
authors: Deisi A
authors: DA
authors: Vaz
mesh_terms: D001412:Bacillus subtilis / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001938:Brazil; D006801:Humans; D013501:Surface-Active Agents / Q000378:metabolism* / Q000633:toxicity; D014733:Vibrio / Q000187:drug effects; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000378:metabolism* / Q000633:toxicity; D053833:Wetlands
chemical_list: D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical
keywords: Biosurfactant; OECD guidelines; environmental compatibility; saponin; surfactin