Dereplication of antimicrobial biosurfactants from marine bacteria using molecular networking.

Biosurfactants are amphiphilic surface-active molecules of microbial origin principally produced by hydrocarbon-degrading bacteria; in addition to the bioremediation properties, they can also present antimicrobial activity. The present study highlights the chemical characterization and the antimicrobial activities of biosurfactants produced by deep-sea marine bacteria from the genera Halomonas, Bacillus, Streptomyces, and Pseudomonas. The biosurfactants were extracted and chemically characterized through Chromatography TLC, FT-IR, LC/ESI-MS/MS, and a metabolic analysis was done through molecular networking. Six biosurfactants were identified by dereplication tools from GNPS and some surfactin isoforms were identified by molecular networking. The half-maximal inhibitory concentration (IC) of biosurfactant from Halomonas sp. INV PRT125 (7.27 mg L) and Halomonas sp. INV PRT124 (8.92 mg L) were most effective against the pathogenic yeast Candida albicans ATCC 10231. For Methicillin-resistant Staphylococcus aureus ATCC 43300, the biosurfactant from Bacillus sp. INV FIR48 was the most effective with IC values of 25.65 mg L and 21.54 mg L for C. albicans, without hemolytic effect (< 1%), and non-ecotoxic effect in brine shrimp larvae (Artemia franciscana), with values under 150 mg L, being a biosurfactant promising for further study. The extreme environments as deep-sea can be an important source for the isolation of new biosurfactants-producing microorganisms with environmental and pharmaceutical use.