i was thinking about characterization of chemical structure and biological activity of the traget compounds. If i am in the right way, So What kind of methods should I use? 

Is it difficult question? should I wait more?

I am afraid your question is not very clear. What exactly you mean by isolated purified compound? If you can explain with an example it would be easier to understand.

I meant purified compounds that are isolated from marine sediment and go through various steps such as isolation, screening, fermentation, extraction and then purification. What about the next step after that?

Are you talking about organic compounds?

what I'm looking for is a new antibiotics from a marine environment.

A simple way you can test substrates antimicrobial activities with challenge test towards specific microorganisms or pathogen. If it is in line with what you think, you can check some of my preliminary research below.

Poster The Potential of “Asam Sunti” Indonesian Fermented Condiment...

Article Preliminary Identification of Inhibition Activities towards ...

Thanks so much Gemilang. I am gonna look at them and I am sure it will be helpful