Integrated GC-MS and UHPLC-HRMS/MS profiling of bioactive compounds from Streptomyces sp. BPA-6 isolated from bees-collected pollen.

Antimicrobial resistance is one of the most current global health challenges, due to the increasing ineffectiveness of antibiotics and the increasing difficulty in treating infections. Approximately two-thirds of microbial antibiotics are produced by actinomycetes, of which approximately 74% come from the genus Streptomyces. In this study, a novel actinomycete strain, Streptomyces sp. BPA-6, isolated from pollen collected by Algerian bees, was investigated for its antimicrobial potential and chemical composition by GC-MS and HPLC-MS analyses. The strain showed strong antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, and Candida albicans, with minimum inhibitory concentrations (MICs) ranging from 62.5 to 250 µg/mL. Molecular identification using 16S rRNA gene sequencing and scanning electron microscopy confirmed the affiliation of the isolate to the genus Streptomyces. GC-MS analysis of the ethyl acetate extract revealed a complex mixture of volatile organic compounds, including fatty acid methyl esters, long-chain hydrocarbons, and sesquiterpenes, many of which are associated with antimicrobial, antioxidant, or anti-inflammatory properties. Complementary HPLC-MS profiling identified more than 40 nonvolatile bioactive compounds, including macrolides (erythromycin), polyethers (nigericin), aminoglycosides (netilmicin), polyketides (cytosporone C), and various sugar and lipid derivatives. The chemical diversity of the extract highlights the rich biosynthetic capacity of BPA-6 and its potential as a source of novel natural products.