5. Conclusion
In this study, the mechanism of SLs sedimentation in multiphase fermentation process was elucidated for the ratio of O/S. 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 rapeseed 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.