Determining butanol inhibition kinetics on the growth of Clostridium pasteurianum based on continuous operation and pulse substrate additions

Abstract

BACKGROUND Clostridium pasteurianum is a well described strain for the conversion of glycerol into butanol. In general, cell growth kinetics depends on the type of glycerol used and the concentration of butanol in the fermentation broth. However, despite the numerous studies existing on the subject, there is limited information in the literature regarding growth inhibition kinetics due to the cytotoxic effect of butanol on cell growth. This can be attributed to the difficulty of growing cells at high butanol concentration which renders the determination of inhibition kinetics a rather challenging task. RESULTS During this study a new approach for the determination of butanol inhibition kinetics on the growth of C. pasteurianum was tested. Specifically, pulses of crude glycerol were applied when steady state was reached during continuous fermentation experiments with increasing butanol concentration in the feed. Combining pulse experiments with batch fermentation at low substrate concentration allowed for accurate determination of the kinetic constants for inhibited growth. This approach also minimized the correlation of the growth constants which often leads to poor identifiability. CONCLUSION The proposed experimental approach showed good identifiability of the kinetic parameters for butanol inhibition of the microbial growth and can be proven valuable for the determination of inhibitory effects of highly toxic compounds. © 2019 Society of Chemical Industry

Modeling of syngas biomethanation and catabolic route control in mesophilic and thermophilic mixed microbial consortia

“…5 and 25 for the mesophilic and the thermophilic model, respectively (table 6). As shown in table 6, the datasets used for model calibration could not support the estimation of parameter combinations including both µmax and ks of the same microbial group, even when estimating only two parameters in the case of the mesophilic syngas biomethanation model [38,39]. Similarly, the importance of kLaH2 and kLaCO and their high collinearity with other parameters in both models would also limit the identifiability of other kinetic parameters if these were included, as other parameters would have to be fixed manually instead (table 6).…”

Acetone–Butanol–Ethanol Production from Eastern Canadian Yellow Birch and Screening of Isopropanol–Butanol–Ethanol-Producing Strains

“…For example, potential production of n-butanol without the formation of acetone has been investigated using Clostridium pasteurianum. [41][42][43][44][45][46][47][48][49] All scientific peer-reviewed open literature revealed that the highest butanol concentration recorded for C. pasteurianum was 21 g/ L during mixed carbon source fermentation (1:1 glucose/glycerol). Even though the C. pasteurianum is unlike other clostridia (e.g., Clostridium beijerinckii) used to produce n-butanol, it generates 1,3-propanediol (1,3-PDO) as a major by-product.…”