SPE 10-1 is a microbial isolate from a brown colored sponge Haliclona sp. Order Haplosclerida Family Chalinidae. Through phylogenetic analysis, the actinomycete was identified as Saccharopolyspora sp. It only had 93% homology known sequences of the group, suggesting it to possibly form a new species.
Morphological and Biochemical tests of Saccharopolyspora SPE 10-1 revealed that it is a gram positive bacteria, did not ferment sugar, produced no indole, underwent mixed acid fermentation pathway, utilized citrate as carbon source and had the presence of catalase enzyme.
SPE 10-1 shake culture in M1 broth was solvent partitioned using methanol, ethyl acetate, and hexane and then dried. Test solutions at 100mg/ml concentration were prepared by dissolving the crude SPE 10-1 extracts in their respective solvents. Ampicillin (50g/ml) was used as positive control, and the uninoculated M1 broth with methanol, ethyl acetate, and hexane respectively served as solvent controls.
Preparative TLC visualized under UV light revealed seven bands and corresponding Rf values were computed. TLC bioautography assay results indicate that SPE 10-1 produced metabolites with antibacterial activity. In particular, the ethyl acetate extract of 10-1 (band 3 and 4) showed initial antibacterial activity against both Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. This indicates therefore, that the solvent ethyl acetate extracted the antibacterial metabolites of SPE 10-1. Disk diffusion method was used to confirm the antibacterial activity of band 3 and band 4, ZOI against Pseudomonas aeruginosa and Staphylococcus aureus for band 3 and 4 was observed.
Initial characterization of the antibacterial metabolite of SPE 10-1 EtOAc extract using UV, FT-IR showed the presence of unsaturated chromophoric compounds with the following functional groups: alcohol, alkane, nitro, carboxylic acid and its derivatives. GC-MS of different bands shows the presence of 7,9-Di-tert-butyl-1-oxaspiro (4,5) deca-6,9-diene-2,8-dione, a compound previously isolated sponges, indicating that Saccharopolyspora sp. is possibly a sponge symbiont, from band 4 2,5-Piperazinedione, 3,6-bis(2-methylpropyl)- and Pyrrolo [1,2-a] pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl)- are some interesting compounds that are found to have medical importance.