Recovery Of Roseoflavin From A Recombinant Streptomyces Davaonensis Strain By Using Biphasic Aqueous Systems

BACKGROUNDRoseoflavin (RoS) is a naturally occurring red color riboflavin analog compound, produced mainly by Streptomyces davaonensis, with a rising profile owing to its antibacterial potential. However, there is a lack of strategies for its downstream processing and the existing ones are limited to chromatographic techniques involving harmful reagents. The use of aqueous two-phase systems (ATPS), a liquid-liquid extraction method, is explored in this work as an alternative strategy to recover and purify RoS from S. davaonensis cultures.RESULTSPolymer-phosphate, alcohol-phosphate and ionic liquid (IL)-phosphate systems that varied in composition were tested, where polyethylene glycol (PEG), ethanol (EtOH) and 1-ethyl-3-methylimidazolium acetate ([C2mim] [OAC]) represent the top phases, and phosphate the bottom phase. The partition behavior of either RoS alone or with contaminants was evaluated. In both cases, RoS showed a preference for top phase in all the systems tested. When cell-free cultures were added to the systems, IL-salt (13% and 30% w/w), EtOH-phosphate [50% tie-line length (TLL)] and PEG8000-phosphate (35% w/w TLL) systems presented the highest RoS recovery (>95%), but separation of RoS and contaminants was not accomplished. The systems that demonstrated separation of RoS and contaminants were the PEG3350- and PEG8000-salt systems, both with a 15% w/w TLL, as RoS and contaminants partitioned to top and bottom phases, respectively.CONCLUSIONThis is the first attempt at using ATPS to recover RoS from S. davaonensis cultures. It has been proven that RoS can be recovered directly from S. davaonensis cultures using biphasic systems. This strategy may represent a greener alternative to chromatographic techniques. (c) 2021 Society of Chemical Industry (SCI).