Separation of cadaverine from fermentation broths by salting-out

BACKGROUND

Cadaverine is an important diamine to synthesize nylon. However, the lower product concentration in the cadaverine production makes the downstream separation more complex and costly, and has become a bottleneck for large-scale production. Therefore, in this study, the salting-out was used to efficiently separate cadaverine in the simulated fermentation broth.

RESULTS

After analyzing the pH of readily soluble potassium salts, three alkaline salting-out agents—K₃PO₄, K₂CO₃ and K₄P₂O₇—were utilized to perform the salting-out separation of cadaverine. The effects of the type and concentration of salting-out agents and cadaverine concentration on the distribution and selection behavior of cadaverine in the simulated fermentation broth were investigated. Particularly, when the concentration of cadaverine was 10 wt% and the K₃PO₄ concentration was 500 g/kg, the recovery rate of cadaverine in the simulated fermentation broth with K₃PO₄ salting-out agent was as high as 99.6%, which was significantly higher than that of other salting-out agents, and only 0.01 wt% cadaverine remained in the aqueous phase.

CONCLUSION

The salting-out ability of the three inorganic salts to cadaverine in the simulated fermentation broth was K₃PO₄>K₂CO₃>K₄P₂O₇. Furthermore, within a certain range of cadaverine concentrations, the content of cadaverine in the aqueous phase and the amount of water residue in the organic phase could be calculated using a linear regression equation. Since inorganic salts have the advantages of good stability, low cost, non-toxicity and harmlessness, the salting-out process established in this study shows good potential for industrial application. © 2024 Society of Chemical Industry (SCI).