4. Conclusion
In this study, the mechanism of SLs sedimentation in multiphase fermentation process was elucidated for the first time. And then UEST was introduced to strengthen the SLs sedimentation rate. The real-time rational in-situ separation of SLs and semi-continuous fermentation with UEST was accomplished to achieve productivity and yield of 2.15 g/L and 0.58 g/g respectively as well as reduce the losses of cells, glucose, and oil by 68.2%, 16.2%, and 65.5%, respectively. The rational in-situ separation and UEST for complex multiphase systems could be extended to other biosurfactant fermentation systems to improve production efficiency.