title: Purification and identification of Bacillus subtilis SPB1 lipopeptide biosurfactant exhibiting antifungal activity against Rhizoctonia bataticola and Rhizoctonia solani.
abstract: This study reports the potential of a soil bacterium, Bacillus subtilis strain SPB1, to produce lipopeptide biosurfactants. Firstly, the crude lipopeptide mixture was tested for its inhibitory activity against phytopathogenic fungi. A minimal inhibitory concentration (MIC), an inhibitory concentration at 50% (IC50%), and an inhibitory concentration at 90% (IC90%) values were determined to be 0.04, 0.012, and 0.02 mg/ml, respectively, for Rhizoctonia bataticola with a fungistatic mode of action. For Rhizoctonia solani, a MIC, an IC50%, and IC90% values were determined to be 4, 0.25, and 3.3 mg/ml, respectively, with a fungicidal mode of action. For both of the fungi, a loss of sclerotial integrity, granulation and fragmentation of hyphal mycelia, followed by hyphal shriveling and cell lysis were observed with the treatment with SPB1 biosurfactant fraction. After extraction, separation, and purification, different lipopeptide compounds were identified in the culture filtrate of strain SPB1. Mass spectroscopic analysis confirmed the presence of different lipopeptide compounds consisting of surfactin isoforms with molecular weights of 1007, 1021, and 1035 Da; iturin isoforms with molecular weights of 1028, 1042, and 1056 Da; and fengycin isoforms with molecular weights of 1432 and 1446 Da. Two new clusters of lipopeptide isoforms with molecular weights of 1410 and 1424 Da and 973 and 987 Da, respectively, were also detected. This study reported the ability of a B. subtilis strain to co-produce lipopeptide isoforms with potential use as antifungal compounds.
authors.affiliation: Unit "Enzymes and Bioconversion," National School of Engineers of Sfax, University of Sfax, Sfax, Tunisia. inesmnif2011@gmail.com.|Higher Institute of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia. inesmnif2011@gmail.com.|Inès Mnif, Unité "Enzyme et Bioconversion," ENIS, BP W 3038, Sfax, Tunisia. inesmnif2011@gmail.com.
authors.forename: Inès
authors.initials: I
authors.lastname: Mnif
authors.affiliation: Faculty of Chemistry, Department of Organic Chemistry, University of Barcelona, Joan XXIII s/n, 08028, Barcelona, Spain.
authors.forename: Ariadna
authors.initials: A
authors.lastname: Grau-Campistany
authors.affiliation: Laboratory of Microbiology, Faculty of Pharmacy, University of Barcelona, Joan XXIII s/n, 08028, Barcelona, Spain.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Coronel-León
authors.affiliation: Higher School of Agriculture of Kef, 7119, Kef, Tunisia.
authors.forename: Inès
authors.initials: I
authors.lastname: Hammami
authors.affiliation: Laboratory "Amélioration et Protection des Ressources Génétiques de l'Olivier," Institut de l'Olivier, University of Sfax, Sfax, Tunisia.
authors.forename: Mohamed Ali
authors.initials: MA
authors.lastname: Triki
authors.affiliation: Laboratory of Microbiology, Faculty of Pharmacy, University of Barcelona, Joan XXIII s/n, 08028, Barcelona, Spain.
authors.forename: Angeles
authors.initials: A
authors.lastname: Manresa
authors.affiliation: Unit "Enzymes and Bioconversion," National School of Engineers of Sfax, University of Sfax, Sfax, Tunisia.|Higher Institute of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.
authors.forename: Dhouha
authors.initials: D
authors.lastname: Ghribi
mesh_terms: D001412:Bacillus subtilis / Q000378:metabolism*; D005659:Fungicides, Industrial / Q000302:isolation & purification / Q000494:pharmacology*; D055666:Lipopeptides / Q000302:isolation & purification / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D025282:Mycelium / Q000187:drug effects; D012232:Rhizoctonia / Q000187:drug effects* / Q000254:growth & development; D012988:Soil Microbiology
chemical_list: D005659:Fungicides, Industrial; D055666:Lipopeptides; C049972:fengycin
keywords: Antifungal; Lipopeptide; Mass spectroscopy; Rhizoctonia sp.; Surfactin, iturin, and fengycin