McCarthy, Peter

Cultivation of microbial populations is a necessity for the use of microbes within the biotechnological and pharmaceutical industries, however, approximately only 1% of bacteria have been successfully cultivated in the lab. Dilution to Extinction (DTE) is a technique which involves serially diluting a microbial suspension to single cell inoculum prior to inoculation in a liquid medium designed to replicate natural aquatic environments. This technique was used here for the cultivation of diverse, potentially novel microbes from the marine sponge, Mycale microsigmatosa. One hundred thirty-six samples were successfully sequenced and identified with the majority belonging to the classes Alphaproteobacteria and Gammaproteobacteria. Furthermore, when combined with miniaturized fermentation, DTE allowed for the isolation and identification of marine natural products (3-Heptyl-3-hydroxy-2,4 (1H, 3H)-quinolinedione and 2-Heptyl-4-hydroxyquinoline) active against Methicillin-resistant Staphylococcus aureus. These metabolites originated from Pseudomonas aeruginosa, an isolate obtained from Mycale microsigmatosa using this technique.