5. Conclusion
According to the physiological
metabolic state of cells, the fed-batch fermentation process for SLs
synthesis can be divided into three
stages: a stage that is limited by
cell production capacity, a stage that is inhibited by high product
concentration, and a stage that is limited by oxygen supply. Based on
the detection of process multi-parameters, we established a data-driven
feedback feeding model. This was combined with analyses of cellular
metabolic mechanisms such that an
optimal production state was achieved in the first and second stages,in
which there was a 4.9% increase in SLs production. Furthermore, the
mechanism-assisted data model was applied to the rational and precise
control of residual oil concentration during semi-continuous SLs
fermentation. The problem associated with oxygen limitation that was
encountered during the third stage was effectively alleviated, thereby
further increasing the SLs productivity to 2.30 g/L/h. The
mechanism-assisted data modeling method developed in this study could be
easily extended to other fermentation processes. We also expect our new
process strategy for the production of SLs to be applied on an
industrial-scale.