To evaluate the production of bioactive secondary metabolites the 44 marine isolates were cultivated in nutritional arrays of 12 different liquid media using Duetz 96-deep well plates. Applying this micro-cultivation system, all steps in the screening procedure, including the fermentation, solvent extraction of fermentation broths, storage of extracts and bioassays, could be efficiently performed in a standard 96-well format. In total, 528 crude extracts were analyzed for the production of antibacterial and antifungal activities in whole-cell agar-based growth inhibition assays against Bacillus subtilis MB964, methicillin-resistant Staphylococcus aureus (MRSA) MB5393, Acinetobacter baumannii MB5973 and the yeast Candida albicans MY1055