Project description:Immobilization of Clostridium acetobutylicum B3 onto fibrous matrix by surface-adsorption was developed and applied to biobutanol production. The immobilized C. acetobutylicum B3 cells formed biofilm and showed dramatically improved butanol tolerance and production rate. DNA array-based transcriptional analysis of C.acetobutylicum B3 biofilm cells was conducted to elucidate the gene expression profile of the biofilm cells. Results showed that about 16% of the whole genome was differentially expressed. The most apparently differentially expressed genes were involved in amino acid transport and metabolism, inorganic ion transport and metabolism, energy production and conversion, and coenzyme transport and metabolism.
Project description:Immobilization of Clostridium acetobutylicum B3 onto fibrous matrix by surface-adsorption was developed and applied to biobutanol production. The immobilized C. acetobutylicum B3 cells formed biofilm and showed dramatically improved butanol tolerance and production rate. DNA array-based transcriptional analysis of C.acetobutylicum B3 biofilm cells was conducted to elucidate the gene expression profile of the biofilm cells. Results showed that about 16% of the whole genome was differentially expressed. The most apparently differentially expressed genes were involved in amino acid transport and metabolism, inorganic ion transport and metabolism, energy production and conversion, and coenzyme transport and metabolism.
Project description:Immobilization of Clostridium acetobutylicum B3 onto fibrous matrix by surface-adsorption was developed and applied to biobutanol production. The immobilized C. acetobutylicum B3 cells formed biofilm and showed dramatically improved butanol tolerance and production rate. DNA array-based transcriptional analysis of C.acetobutylicum B3 biofilm cells was conducted to elucidate the gene expression profile of the biofilm cells. Results showed that about 16% of the whole genome was differentially expressed. The most apparently differentially expressed genes were involved in amino acid transport and metabolism, inorganic ion transport and metabolism, energy production and conversion, and coenzyme transport and metabolism. Samples for biofilm cells and planktonic cells were withdrawn at four diffierent fermentation phases. The gene expression pattern of biofilm cells were investigated relative to that of planktonic cells from the same phase. The experiment was carried out twice independently. Cotton fibrous matrix (60 g/L) was used as biofilm carrier.
Project description:Immobilization of Clostridium acetobutylicum B3 onto fibrous matrix by surface-adsorption was developed and applied to biobutanol production. The immobilized C. acetobutylicum B3 cells formed biofilm and showed dramatically improved butanol tolerance and production rate. DNA array-based transcriptional analysis of C.acetobutylicum B3 biofilm cells was conducted to elucidate the gene expression profile of the biofilm cells. Results showed that about 16% of the whole genome was differentially expressed. The most apparently differentially expressed genes were involved in amino acid transport and metabolism, inorganic ion transport and metabolism, energy production and conversion, and coenzyme transport and metabolism. Samples for biofilm cells and planktonic cells were withdrawn at four diffierent fermentation phases. The gene expression pattern of biofilm cells were investigated relative to that of planktonic cells from the same phase. The experiment was carried out twice independently. Cotton fibrous matrix (60 g/L) was used as biofilm carrier.
Project description:Previously, we performed DNA array-based transcriptomic analysis of Clostridium acetobutylicum biofilm adsorbed onto fibrous matrix in batch fermentation. Here, to further shed light on the transcriptomic modulation of maturing Clostridium acetobutylicum biofilm, we performed the DNA array-based transcriptomic analysis in repeated-batch fermentation. Significant time course changes in expression levels were observed for the genes involved in amino acid metabolism, oligopeptide ABC transporter, nitrogen fixation, and various other processes.
Project description:Previously, we performed DNA array-based transcriptomic analysis of Clostridium acetobutylicum biofilm adsorbed onto fibrous matrix in batch fermentation. Here, to further shed light on the transcriptomic modulation of maturing Clostridium acetobutylicum biofilm, we performed the DNA array-based transcriptomic analysis in repeated-batch fermentation. Significant time course changes in expression levels were observed for the genes involved in amino acid metabolism, oligopeptide ABC transporter, nitrogen fixation, and various other processes. Repeated-batch fermentation was carried out in 2-L stainless steel columns packed with 40 g of cotton towel ?cut into pieces?approximately 3 cm × 5 cm) containing 1.5 L of P2 medium. Medium circulation rate was maintained at 35 mL/min via a peristaltic pump and the temperature was controlled at 37°C. Fermentation broth was replaced with fresh P2 medium every 12 h. Samples were withdrawn at 6 h after the medium replacement at predetermined interval, except for the last 3 samples. The last 3 samples were withdrawn at 12 h, 15 h, and 17 h after the medium replacement, respectively, to study the transcriptomic response to the adverse condition at the end of fermentation. A total of 8 samples were withdrawn over a period of 7 days, and time course gene expression profiles were studied.
Project description:Caproate (hexanoate) and other medium-chain fatty acids are valuable platform chemicals produced by processes utilizing petroleum or plant oil. Clostridium kluyveri, growing on short chain alcohols (notably ethanol) and carboxylic acids (such as acetate) is noted for its ability to perform chain elongation to produce 4- to 8-carbon carboxylates. C. kluyveri has been studied in monoculture and coculture conditions, which lead to relatively modest carboxylate titers after long fermentation times. To assess the biosynthetic potential of C. kluyveri for caproate production from sugars through coculture fermentations, in the absence of monoculture data in the literature suitable for our coculture experiments, we first explored C. kluyveri monocultures. Some monocultures achieved caproate titers of 150 to over 200 mM in 40–50 h with a production rate of 7.9 mM/h. Based on that data, we then explored two novel, syntrophic coculture partners for producing caproate from sugars: Clostridium acetobutylicum and Clostridium saccharolyticum. Neither species has been cocultured with C. kluyveri before, and both demonstrate promising results. Our experiments of C. kluyveri monocultures and C. kluyveri—C. saccharolyticum cocultures demonstrate exceptionally high caproate titers (145–200 mM), fast production rates (3.25–8.1 mM/h), and short fermentation times (18–45 h). These results represent the most caproate produced by a C. kluyveri coculture in the shortest known fermentation time. We also explored the possibility of heterologous cell fusion between the coculture pairs similar to the results seen previously in our group with C. acetobutylicum and Clostridium ljungdahlii. Fusion events were observed only in the C. acetobutylicum—C. kluyveri coculture pair, and we offer an explanation for the lack of fusion between C. saccharolyticum and C. kluyveri. This work supports the promise of coculture biotechnology for sustainable production of caproate and other platform chemicals.
Project description:Clostridium acetobutylicum is an organism involved in the production of acetone and butanol by traditional acetone-butanol-ethanol fermentation (ABE). We report the draft genome sequence of C. acetobutylicum strain GXAS18-1, which can produce ABE directly from cassava flour.