A novel Enterococcus durans with antimicrobial, anti-diabetes and anti-alzheimer activities isolated from Egypt

Enterococcus sp. is a subset of lactic acid bacteria that have beneficial effects on human health including prevention of gut chronic diseases, controlling Alzheimer and diabetes. The study involves morphological and biochemical identification of Enterococcus sp. and 16S rRNA gene sequencing methods, alongside an exploration of it's antimicrobial, anti-diabetes and anti-Alzheimer efficacy. The cell-free supernatant (CFS) derived from this isolate (Enterococcus durans) exhibited a significant antibacterial activity against both Gram-positive (Bacillus subtilis, Staphylococcus aureus, Enterococcus faecalis) with inhibition zones of 31.1, 33 and 27 mm, respectively and Gram-negative (Escherichia coli, Klebsiella pneumoniae, Salmonella typhi) bacteria, recording inhibition zones of 24, 25 and 30 mm, respectively. The least values of MIC and MBC were 15.62 µg/ml and 31.25 µg/ml, respectively; in case of Bacillus subtilis and Staphylococcus aureus. The highest MIC and MBC were 62.5 µg/ml and 250 µg/ml respectively, when testing CFS against Klebsiella pneumonia. Notably, the stability of CFS was maintained at various temperatures, including autoclaving conditions (121 ℃). The isolate displayed tolerance across a wide pH range (2.5-9.5), with enhanced activity observed at acidic pH levels. Butyrylcholinesterase inhibition was estimated to be 84.6%, while amylase inhibition was 97.6% & 94.2%, respectively. GC-MS revealed metabolites not defined previously in enterococci: 1H-purin-6-amine, [(2-fluorophenyl) methyl]-(29.72%), hexadecanoic acid, 2, 3 dihydroxypro polyester (18.60%), oleic acid (11.60%) and 9-octadecenamide (6.54%). Hence, our strain is a reservoir of strong bioactive compounds, with antimicrobial, anti-diabetes and anti- Alzheimer potentials.