Effective extraction of tylosin and spiramycin from fermentation broth using thermo‐responsive ethylene oxide/propylene oxide aqueous two‐phase systems

Abstract

Recyclable aqueous two-phase systems with thermo-responsive phase-forming materials have been employed to separate macromolecules; however, these systems have achieved very limited separation efficiency for small molecules, such as antibiotics. In this study, aqueous two-phase systems composed of the ethylene oxide/propylene oxide copolymer and water were developed to extract alkaline antibiotics from the fermentation broth. In the aqueous twophase systems with an ethylene oxide ratio of 20 and propylene oxide ratio of 80, the partition coefficients of tylosin and spiramycin reached 16.87 and 20.39, respectively, while the extraction recoveries were 70.67 and 86.70%, respectively. Coupled with mechanism analysis, we demonstrated the feasibility of extracting alkaline antibiotics using this aqueous two-phase system, especially for 16-membered macrolide antibiotics. The molecular dynamic simulation was employed to visualize the process of dual-phase formation and the partition behavior of antibiotics in an aqueous two-phase system. The dynamic simulation revealed the binding energy between the antibiotic and ethylene oxide/propylene oxide copolymers, which provides a simple indicator for screening suitable antibiotics in aqueous two-phase systems. Our recyclable aqueous two-phase systems provide a robust approach for the extraction of 16-membered macrolide antibiotics with ease of operation and high recovery rates, which is appropriate for large-scale extraction in the fermentation industry.

Selectivity of PEG/Salt Aqueous Two-Phase System Enhanced by Surfactant@MWCNT Composites

“…Since there are no traditional volatile organic compounds present in ATPS and the bulk of both phases is mainly composed of water, ATPS can provide a mild environment for bioactive molecules, allowing them to maintain their original structure and function. , Besides, ATPS liquid–liquid extraction technology can avoid the adverse effects of organic solvents on the environment, and the phase components of ATPS can be recycled. , Therefore, ATPS has biocompatibility and environmental friendliness and has been considered as a new type of green separation system. However, ATPS so far has not been applied on a large scale in the field of separation and purification due to drawbacks such as high viscosity and long phase separation time for surfactant-based ATPS, , the restricted difference in polarities between the two phases of polymer-based ATPS, , and the low selectivity for target molecules. , …”

“…However, ATPS so far has not been applied on a large scale in the field of separation and purification due to drawbacks such as high viscosity and long phase separation time for surfactant-based ATPS, 5,6 the restricted difference in polarities between the two phases of polymer-based ATPS, 7,8 and the low selectivity for target molecules. 9,10 To date, many researchers have tried to improve ATPS performance by developing novel ATPS (for example, ionic liquid-based ATPS 11−13 ) or by using adjuvants (such as adding surfactants, 14 acetonitrile, 15 or ionic liquids 16−18 into PEG/salt ATPS). It has been concluded that these two methods can help improve the extraction efficiency of ATPS under certain conditions, however, the selectivity of ATPS for the molecules with similar structures or properties is still limited; actually, so far, the selectivity of ATPS is far from satisfactory.…”