Redox potential control in anaerobic Clostridium beijerinckii fermentation using single-use vessels
March 4-8, 2018
Redox potential is an important physiochemical factor which measures the tendency of the medium to acquire electrons. In Clostridium beijerinckii fermentation, redox potential indicates the status of the NAD(P)+ pool regeneration which directs the electron flow leading to solvent production including butanol. In this study, anaerobic C. beijerinckii fermentation was conducted in Eppendorf BioBLU® 3f Single-Use Vessels controlled by the BioFlo® 120 bioprocess control station. The parameters being monitored throughout the fermentation were redox potential and pH using ISM® redox/pH sensors. The objectives of this study were (1) to investigate the effects of redox control on the growth and butanol production of C. beijerinckii; and (2) to validate the suitability of the BioFlo 120 and BioBLU 3f Single-Use Vessel for anaerobic fermentation applications. When C. beijerinckii was grown without redox control, a continuous change of redox potential was observed in the broth. When fermentation ended at 124 h, the optical density at 600 nm (OD600) was 0.8, glucose consumption was 33 % and butanol production was limited. When the redox potential was controlled at -500 mV by redox sensor guided addition of Na2S·9H2O solution, the OD600 was 1.6, glucose consumption was 51 %, and butanol production showed a 2-fold increase. In summary, with the combination of ISM redox sensor and BioBLU Single-Use Vessel, the high variability of redox potential during C. beijerinckii fermentation can be actively controlled to drastically increase biomass growth and solvent production.
Ying Yang and Ma Sha, "Redox potential control in anaerobic Clostridium beijerinckii fermentation using single-use vessels" in "Microbial Engineering", Prof. Eli Keshavarz-Moore , University College London, England Dr. Barry Buckland, BiologicB, USA Eds, ECI Symposium Series, (2018). http://dc.engconfintl.org/microbial/24