Antibacterial and anticancer activity of ε-poly-L-lysine (ε-PL) produced by a marine Bacillus subtilis sp.

A marine Bacillus subtilis SDNS was isolated from sea water in Alexandria and identified using 16S rDNA sequence analysis. The bacterium produced a compound active against a number of gram negativeve bacteria. Moreover, the anticancer activity of this bacterium was tested against three different human cell lines (Hela S3, HepG2 and CaCo). The highest inhibition activity was recorded against Hela S3 cell line (77.2%), while almost no activity was recorded towards CaCo cell line. HPLC and TLC analyses supported evidence that Bacillus subtilis SDNS product is ε-poly-L-lysine. To achieve maximum production, Plackett-Burman experimental design was applied. A 1.5 fold increase was observed when Bacillus subtilis SDNS was grown in optimized medium composed of g/l: (NH(4))(2) SO(4), 15; K(2)HPO(4), 0.3; KH(2)PO(4), 2; MgSO(4) · 7 H(2)O, 1; ZnSO(4) · 7 H(2)O, 0; FeSO(4) · 7 H(2)O, 0.03; glucose, 25; yeast extract, 1, pH 6.8. Under optimized culture condition, a product value of 76.3 mg/l could be obtained. According to available literature, this is the first announcement for the production of ε-poly-L-lysine (ε-PL) by a member of genus Bacillus.