ATPS applied to extraction of small molecules – polycetides – and simultaneous clarification of culture media with filamentous microorganisms

Aqueous two-phase systems (ATPS) were applied for extraction of small molecules (polycetides) – retamycin, an anthracyclin, and two red pigments, rubropunctamin and monascorubramin – from the whole culture media of Streptomyces olindensis and Monascus purpureus. ATPS allows, in one step, the separation of the small hydrophobic molecules in the PEG rich phase, from the filamentous microorganisms, which remains in the salt phase. Through experimental designs, the main variables and their levels were defined, as follows: for retamycin extraction, PEG 6000 (10%, w/w), phosphate at 20% (w/w) and pH 6.0 led to the higher partition coefficient, Kr = 8.2, and yield = 91.3%; for red pigments, the statistical analysis indicate PEG 6000 (20%, w/w) and phosphate at 15% (w/w), for a high partition coefficient, (Kpig = 113 and 150).