Biosurfactant-Producing Bacillus velezensis PW192 as an Anti-Fungal Biocontrol Agent against Colletotrichum gloeosporioides and Colletotrichum musae

Abstract

In this study, plant-root-associated Bacillus species were evaluated as antifungal biocontrol agents by analyzing the production of surface bioactive molecules known as lipopeptide biosurfactants. This study aimed to isolate and characterize antifungal biosurfactant-producing Bacillus bacterium. Bacillusvelezensis PW192 was isolated from the rhizosphere of Lagerstroemia macrocarpa var macrocarpa and identified based on phylogenetic analysis of the 16S rRNA gene. The biosurfactant was excreted to cultured supernatant and exhibited emulsification power up to 60% and a decrease in surface tension from 72 in distilled water to 21 mN/m. The surface tension properties were stable in a broad range of pH from 6 to 10, in high temperatures up to 100 °C, and in salinities with a NaCl concentration up to 12% (w/v). Starting from 0.5 mg of acid, precipitated crude biosurfactant exhibited antifungal activity toward Anthracnose, caused by the phytopathogens Colletotrichum gloeosporioides and C. musae. The chemical structures of the biosurfactant were structurally characterized as lipopeptides fengycin A and fengycin B. The stability of the biosurfactant, as well as the antifungal properties of B. velezensis PW192, can potentially make them useful as agricultural biocontrol agents, as well as in other biotechnological applications.

Antifungal Potential of Bacillus velezensis CE 100 for the Control of Different Colletotrichum Species through Isolation of Active Dipeptide, Cyclo-(D-phenylalanyl-D-prolyl)

“…The lipopeptides such as surfactin, iturin, and fengycin are major bioactive compounds derived from the genus Bacillus and they mainly attack cell membranes of the target pathogens through osmotic disturbance due to pore formation and ion leakage, interaction with lipid layers, and structural alteration of the cell membrane, and interference of membrane integrity, disruption, and solubilization with pore formation [46]. Suppression of growth of Colletotrichum species by these lipopeptides has been well documented in several reports [47][48][49]. Iturin A purified from B. amyloliquefaciens MG3 strongly restricted mycelial growth and spore germination of C. gloeosporioides.…”

Broad-Spectrum Antifungal, Biosurfactants and Bioemulsifier Activity of Bacillus subtilis subsp. spizizenii—A Potential Biocontrol and Bioremediation Agent in Agriculture

“…Stability at different temperatures was evaluated by incubating the CL 84 solutions at 0, 5, 70 and 100 °C for 1 h and at 120 °C for 20 min; the samples were then cooled to room temperature and the emulsification indexes were measured. The pH stability was studied by adjusting the CL 84 solutions to different pH values (2–12) using HCl or NaOH solutions and then the emulsifying activity was measured as previously described [ 65 , 85 ]. All the experiments were carried out in triplicate.…”

Bacteria Halotolerant from Karst Sinkholes as a Source of Biosurfactants and Bioemulsifiers

“…The bottles were incubated in a rotary culture system at 7 rotations per minute (rpm) at 35 °C for 24 h, and then 10 mL of fresh TSB culture medium was added [ 28 ]. Every 24 h, two bottles were removed to determine the BS and BE activity, up to 96 h, as described in numbers ( Section 2.3.1 and Section 2.3.2 ); in addition, stability at 5 and 10% NaCl was evaluated at the time (h) of the highest BS and BE activity [ 29 ].…”