Purification and characterization of antibacterial surfactin isoforms produced by Bacillus velezensis SK

Abstract

Bacillus velezensis SK having broad-spectrum antimicrobial activity has been isolated from soil. The efficient extraction of antimicrobial compounds produced in various mediums has been done using Diaion HP-20 resin. Further, characterization of an antimicrobial compound by TLC, FTIR, in-situ bioautography analysis revealed the presence of cyclic lipopeptides, which is then purified by the combination of silica gel, size exclusion, dual gradient, and RP-HPLC chromatography techniques. Growth kinetic studies showed that Bacillus velezensis SK produces a mixture of lipopeptides (1.33 gL−1). The lipopeptide exhibits good pH (2–10) and temperature stability up to 80 °C. LC–ESI–MS analysis of partially purified lipopeptide identified variant of surfactin, further analysis of purified chromatographic fractions revealed the occurrence of most abundant C15-surfactin homologues (m/z 1036.72 Da). The isolated surfactin exhibits good antimicrobial activity (1600 AU/ml) against drug-resistant food-born B. cereus and human pathogen Staphylococcus aureus. Hence, identified strain B. velezensis SK and its potent antibacterial surfactin lipopeptide could be used in various food and biomedical applications.

Effect of fermentation on structural properties and antioxidant activity of wheat gluten by Bacillus subtilis

“…Bacillus subtilis is a Gram-positive bacterium found in soil and is widely used in biological fermentation processes in the food industry. Bacillus subtilis has the ability to produce antimicrobial proteins and a variety of protease activities such as antifungal proteins (5,6), nattokinase (7), pectinase (8) and various bioactive peptides such as antimicrobial peptides and antioxidant peptides etc. (9)(10)(11).…”

LC-MS and Transcriptome Analysis of Lipopeptide Biosynthesis by Bacillus velezensis CMT-6 Responding to Dissolved Oxygen

“…More genes with transmembrane transport function means that more protein translocation channels could be synthesized, including those involved in the secretion of lipopeptides, extracellularly resulting in an increase in production [ 16 , 17 ]. A greater number of genes with oxidation–reduction processes reduces the conversion of NADH into NAD to ensure the oxidation–reduction state (NADH/NAD + ) balance at high DO concentrations [ 18 ], resulting in more ATP production with an increased utilization of substrate by bacteria, culminating in an accelerated metabolism to the synthesis of more lipopeptide [ 9 , 19 ].…”

Dairy and Wine Industry Effluents as Alternative Media for the Production of Bacillus-Based Biocontrol Agents

“…BioSol021 resulted in decreased residual concentrations of lactose, glucose and fructose in the cultivation broth at the end of the cultivation, with the consumption rates 30%, 70% and 32%, respectively. Previous studies have shown that the majority of Bacillus strains prefer glucose as the easily fermentable carbon source for biomass growth and lipopeptide production, with a suggested initial glucose concentration in the cultivation medium in the range of 20–40 g/L [ 53 , 54 ]. Lowering the content of carbon sources, as the main contaminants of waste-based media, is significant from the point of view of ecological efficiency of the created bioprocess solution, considering the positive impact on reduction in environmental burden.…”