On-line Characterization of Metabolic State in Batch Cultivation of Clostridium diolis for 1,3-Propanediol Production Using NADH+H+ Fluorescence

Abstract

NADH is a coenzyme which plays a central role in cellular growth and metabolism. It is an intracellular fluorophore which fluoresces at 460 nm when cells are irradiated by 340 nm wavelength of light. The application of NADH+H(+) fluorescence measurement for characterization of biomass and its metabolic activity during batch fermentation of 1,3-propanediol (1,3-PD) using Clostridium diolis was investigated in this study. A linear correlation between net fluorescence and biomass concentration was observed during both the initial and final phases of 1,3-PD fermentation. This could be used as an on-line indicator of biomass concentration inside the bioreactor thereby eliminating the need for sampling and off-line analysis for establishing biomass concentration during these phases. Also a sharp decline in the NADH+H(+) fluorescence value was obtained towards the end of fermentation which could be a significant on-line, in situ signal of substrate depletion in the bioreactor and therefore possible fresh nutrient feed for enhanced production of 1,3-PD by repetitive and/or various fed-batch cultivation(s). This is the first report on the use of NADH + H(+) fluorescence measurement technique for 1,3-PD fermentation.

Production of 1,3-propanediol from glycerol via fermentation by Saccharomyces cerevisiae

“…21,22 Although the bioconversion of glycerol to 1,3propanediol via fermentation has been extensively investigated, it appears that only several species of the Enterobacteriaceae family such as Citrobacter freundii, Klebsiella pneumoniae, Enterobacter agglomerans, Lactobacilli brevis, and Lactobacilli buchneri, as well as Clostridium butyricum and Clostridium pasteurianum, are able to form 1,3propanediol. 2,21,23,[24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] The dissimilation of glycerol in these organisms is strictly linked to their capacity to synthesize the highly reduced product 1,3-propanediol. 39 The potential for using these organisms at the industrial level is limited due to their pathogenicity, the requirement for strict anaerobic conditions, the need for rich nutrient supplementation, and the lack of availability of the genetic tools and physiological knowledge necessary for their effective manipulation.…”