A new linear glyceryl acid derived heptapeptide (1), together with known isocoumarin antibiotic, Y-05460M-A (2), were isolated from the culture of the deep sea sediment strain SI 79 classified as "Paenibacillus profundus" sp. nov. Their structures were determined by 1D- and 2D- NMR techniques and ESI-MS/MS experiments. HPLC analysis of the Marfey derivatives in comparison to their analogs of authentic amino acids revealed that all amino acids in peptide 1, with an exception of Val, have the D-configuration. The compound 1 showed inhibitory activity against Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Enterococcus faecium as well as cytotoxic and moderate colony growth inhibitory activity against SK-MEL-28 cell line.