Metabolites from Lactococcus lactis subsp. lactis: Isolation, Structure Elucidation, and Antimicrobial Activity

Abstract

Herein, we disclose the identification of novel metabolites from a potential probiotic strain, Lactococcus lactis subsp. lactis, obtained from traditional dairy milk samples collected in Maharashtra, India (in January 2021). Isolated metabolites include pyrazin-2-carboxamide [1, pyrazinamide, a potential antitubercular drug], 3,5-dihydroxy-6-methyl-2,3-dihydro-4H-pyran-4-one (2, DDMP), 2,4-di-tert-butylphenol (3), and hexadecanoic acid (4, palmitic acid). The chemical structures of these metabolites were elucidated through extensive 1D NMR ( 1 H and 13 C) and 2D NMR (HSQC, HMBC, and NOESY) analyses, high-resolution mass spectrometry, high-performance liquid chromatography, and single-crystal X-ray crystallography. Furthermore, these novel metabolites exhibited potent inhibitory activities against various bacteria, fungi, and yeast strains with minimum inhibitory concentrations ranging between 1.56 and 25 μg/mL, and compounds 1 and 3 were found to be most active against a wide range of microbial strains tested.

Probiotic evaluation, adherence capability and safety assessment of Lactococcus lactis strain isolated from an important herb “Murraya koenigii”

“…These findings were based on phenotypic and sequencing analyses. Early research has led to the strong notion that dairy products, such as milk, yogurt 28 , 29 , cheese and sourdough 30 , 31 are the primary source of Lactococcus sp . Nonetheless, accumulating evidence from multiple studies has demonstrated the isolation of Lactococcus species from non-dairy sources such as fresh vegetables 32 , fruits 33 , leaves 34 , and silage 35 .…”

Incorporation of Lactococcus lactis and Chia Mucilage for Improving the Physical and Biological Properties of Gelatin-Based Coating: Application for Strawberry Preservation

“…Gajbhiye et al [16] isolated and purified antifungal compounds such as cyclo-dipeptide from L. lactis, demonstrating the potential of L. lactis to be applied to fungal control in food preservation. Navale et al [17] found that L. lactis collected from milk showed effective inhibition of fungi because of the presence of metabolites such as phenolic compounds. Hence, considering the probiotic function and potential antifungal activity of L. lactis, it was expected to be incorporated as an ideal bioactive substance to enhance the antifungal properties of the GN coating.…”