Dissolved oxygen control strategy for improvement of TL1-1 production in submerged fermentation by Daldinia eschscholzii

Xing-Chen Wei,Liu Tang,Yan-Hua Lu

doi:10.1186/s40643-016-0134-4

Xing-Chen Wei, Liu Tang + Show 1 more

Open Access

https://doi.org/10.1186/s40643-016-0134-4

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Abstract

Background2,3-Dihydro-5-hydroxy-2-methylchromen-4-one (TL1-1) is a phenolic compound with significant anti-fungal and anti-cancer activities produced by Daldinia eschscholzii (D. eschscholzii). However, studies have rarely been reported on the fermentation process of D. eschscholzii due to the urgent demand for its pharmaceutical researches and applications.ResultsIn this work, the optimal fermentation medium for improved TL1-1 yield was first obtained in a shake flask. As the fermentation process was scaling up, the marked effects of dissolved oxygen (DO) on cell growth and TL1-1 biosynthesis were observed and confirmed. Controlling a suitable DO level by the adjustment of agitation speed and aeration rate remarkably enhanced TL1-1 production in a lab-scale bioreactor. Moreover, the fermentation of D. eschscholzii was successfully applied in 500-L bioreactor, and TL1-1 production has achieved 873.63 mg/L, approximately 15.4-fold than its initial production (53.27 mg/L).ConclusionsDissolved oxygen control strategy for enhancing TL1-1 production was first proposed. Furthermore, control of the appropriate DO level has successfully performed for improving TL1-1 yield and scale-up of D. eschscholzii fermentation process.

Highlights

Effects of fermentation medium on production of TL1‐1 Due to low concentration of TL1-1 in M1 which was used for isolation of natural product by D. eschscholzii, it is expected to obtain a fermentation medium suitable for higher yield of TL1-1 through selection of seven media and optimization of carbon source
The explanation may be that the lowest speed could cause insufficient oxygen concentration while highest one may create shear stress, both of which may have affected target product synthesis (Xu and Zhong 2011; Xia et al 2014)
These operating conditions in 50-L bioreactor seemed to be favorable for TL1-1 formation and the hypothesis that dissolved oxygen (DO) control strategy promoted target product biosynthesis was further confirmed

Summary

Results

The optimal fermentation medium for improved TL1-1 yield was first obtained in a shake flask. As the fermentation process was scaling up, the marked effects of dissolved oxygen (DO) on cell growth and TL1-1 biosynthesis were observed and confirmed. Controlling a suitable DO level by the adjustment of agitation speed and aeration rate remarkably enhanced TL1-1 production in a lab-scale bioreactor. The fermentation of D. eschscholzii was successfully applied in 500-L bioreactor, and TL1-1 production has achieved 873.63 mg/L, approxi‐ mately 15.4-fold than its initial production (53.27 mg/L)

Conclusions

Methods

Results and discussion