Abstract: A bacterium strain, GAS 00152, was isolated form marine sediment collected at a depth of 2476 m in the South China Sea. This bacterium was identified as Bacillus amyloliquefaciens by analysis of its 16S rRNA gene sequence. Chemical investigation of the fermentation broth of GAS 00152 was carried out using silica gel column chromatography, PTLC and semi-preparative HPLC. Twelve compounds were isolated and identified as 4-phenyl-3-butenamide (1), 2-phenylacetamide (2), phenylacetic acid-2-(4-hydroxyl phenyl) ethyl ester (3), 4-hydroxyphenethylethanol (4), cyclo-(Gly-Leu) (5), cyclo-(Gly-Leu) (6), cyclo-(Gly-L-Pro) (7), cycl-(D-Pro-L-Val) (8), cyclo-(4-hydroxy-Pro-Leu) (9), cyclo-(N-methyl-Gly-Phe) (10 ), cyclo-(L-2-hydroxy-Pro-Phe) (11) and cyclo- (pipecolinyl-phenylalanine) (12) on the basis of spectroscopic data and comparison with literatures. Among them,Compound 1 was a new natural product. Compounds 1-12 were evaluated for their antibacterial activity. Compound 9 showed moderate activities against C. papayae and P. musrarum.

Key words: marine bacterium, Bacillus amyloliquefaciens, secondary metabolite, antibacterial activity