BINARY CO-CULTURE SELECTION FROM MARINE-DERIVED MICROORGANISMS FOR DIFFERENTIAL PRODUCTION OF SPECIALIZED METABOLITES

Nowadays the discovery of new compounds from microorganisms has substantially decreased. Genomic studies have shown that certain genes are not expressed under standard laboratory conditions. In order to overcome this problem, several methods including microorganism co-culture have been developed. The aim of this work was to select binary co-cultures of marine-derived microorganisms to pursue further chemical studies. From 15 microorganisms, 151 interactions assays in solid media were performed using two different methodologies: distance assays and contact assays that allowed to distinguish between interactions due to diffusible compounds or due to cell-cell contact. For distance assays, the metabolic production changes were evaluated using 3 zones: two corresponding to each microorganism colony, and a third zone corresponding to the interaction zone. This division zone strategy allowed to assess the diffusion compounds gradient, and to suggest the producer microorganism of the induced compounds. The metabolic production of the co-cultures was evaluated using HPLC-DAD and NMR. Seven co-cultures were identified to be able to induce changes in the metabolic production. Remarkably, the co-culture between the fungus Purpureocillium sp. PNM-67 and the bacteria Rhodococcus sp. RKHC-26 or Gordonia sp. PNM-25 induce production of a red dye in the fungus. These are the first successful examples of interaction between a fungus and a mycolic acid-containing bacteria.