Journal Article

Purification and identification of Bacillus subtilis SPB1 lipopeptide biosurfactant exhibiting antifungal activity against Rhizoctonia bataticola and Rhizoctonia solani

Ghribi, Dhouha, Mnif, Inès, Triki, Mohamed Ali, Coronel-León, Jonathan, Grau-Campistany, Ariadna, Manresa, Angeles, Hammami, Inès

2016

Overview

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.

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Antibiotics / antifungal agents / antifungal properties / Antimicrobial agents / Aquatic Pollution / Atmospheric Protection/Air Quality Control/Air Pollution / Bacillus subtilis / Bacillus subtilis - metabolism / Bacteria / Bioremediation / biosurfactants / Contamination / Crop diseases / culture filtrates / Disease prevention / Earth and Environmental Science / Ecotoxicology / Environment / Environmental Chemistry / Environmental Health / Environmental science / Fatty acids / Filtrate / Fungi / Fungicides, Industrial - isolation & purification / Fungicides, Industrial - pharmacology / hyphae / inhibitory concentration 50 / iturin / Laboratories / Lipopeptides - isolation & purification / Lipopeptides - pharmacology / Macrophomina phaseolina / mechanism of action / Microbial Sensitivity Tests / Microorganisms / minimum inhibitory concentration / Mode of action / Molecular weight / mycelium / Mycelium - drug effects / Pathogens / Pesticides / Plant diseases / plant pathogenic fungi / Research Article / Rhizoctonia - drug effects / Rhizoctonia - growth & development / Rhizoctonia bataticola / Rhizoctonia solani / sclerotia / soil bacteria / Soil contamination / Soil Microbiology / spectroscopy / Studies / Surfactants / surfactin / Thanatephorus cucumeris / Waste Water Technology / Water Management / Water Pollution Control