Abstract
The effects of oxidoreduction potential (ORP) regulation on the process of propionic acid production by Propionibacterium freudenreichii CCTCC M207015 have been investigated. Potassium ferricyanide and sodium borohydride were determined as ORP control agents through serum bottle experiment. In batch fermentation, cell growth, propionic acid and by-products distribution were changed with ORP levels in the range of 0-160mV. Based on these analysis results, an ORP-shift control strategy was proposed: at first 156h, ORP was controlled at 120mV to obtain higher cell growth rate and propionic acid formation rate, and then it was shifted to 80mV after 156h to maintain the higher propionic acid formation rate. By applying this strategy, the optimal parameters were obtained as follows: the propionic acid concentration 45.99g L(-1), productivity 0.192g L(-1) h(-1), the proportion of propionic acid to total organic acids 92.26% (w/w) and glycerol conversion efficiency 76.65%. The mechanism of ORP regulation was discussed by the ratio of NADH/NAD(+), ATP levels, and metabolic flux analysis. The results suggest that it is possible to redistribute energy and metabolic fluxes by the ORP-shift control strategy, and the strategy could provide a simple and efficient tool to realize high purity propionic acid production with glycerol as carbon source.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
