A novel antimicrobial substance produced by Lactobacillus rhamnous LS8

- A novel antimicrobial substance (C6H11N3O2) produced by lactic acid bacteria was firstly purified and identified.
- C6H11N3O2 has broad antimicrobial spectrum including multidrug resistant pathogens.
- C6H11N3O2 is potential biopreservative or new antibiotic.

Superbugs or multi-drug resistant pathogens are not only clinical issue but also highlighted in food safety. However, development of new antibiotics and safe preservatives is declining. A novel workflow was used to purify antimicrobial substance produced by Lactobacillus rhamnosus LS-8, in which ethyl acetate extraction, polypeptide column and HPLC were involved in the purification process. Subsequently, a novel antimicrobial substance was purified and identified as 4,6-dimethyl-1,2,5-triazepane-3,7-dione (C6H11N3O2) by mass spectrum, 1H NMR and 13C NMR analysis. Fortunately, it has significant inhibitory effect on both gram-positive and gram negative strains including multi-drug resistance pathogens. Also it had good heat stability and resistant to proteolytic enzymes, however, it was only active in acidic condition. The results of scanning electron microscopy (SEM) and transmission electron microscope (TEM) showed that LS-8-25 destroyed the ultrastructure of S. aureus and E. coli. The discovery is adding a new variety of antimicrobial substance produced by lactic acid bacteria.