Project description:Clostridium ljungdahlii can utilize CO as energy source during autotrophic growth. C. ljungdahlii grows sufficiently in CO and produces ethanol as the main product. In this study, C. ljungdahlii wild type and mutant were fermented on CO. C. ljungdahlii produced more ethanol than the ΔadhE1 mutant. The results showed that aldehyde dehydrogenase inactivation led to inefficient metabolism in C. ljungdahlii. Thus, comparative transcriptomes among cells grown on CO of WT and ΔadhE1 mutant were performed to investigate gene expression profiles based on three biological replicates.
Project description:Clostridium ljungdahlii not only utilizes CO, but also H2 as energy source during autotrophic growth. And C. ljungdahlii also grows in fructose fermentation. In theory, fructose is a more energetically favourable energy source than syngas in the fermentation of C. ljungdahlii. However, C. ljungdahlii grows insufficiently in fructose and produces less acetate and ethanol, compared to syngas fermentation. In this study, C. ljungdahlii wild type and mutants were fermented on fructose. C. ljungdahlii produced less ethanol than the ΔadhE1 mutant and consumed less fructose. The ΔadhE1+2 mutant cannot grow in the syngas fermentation and produced less ethanol among the three strains. The results showed that aldehyde dehydrogenase inactivation led to efficient metabolism in C. ljungdahlii and the bifunctional aldehyde/alcohol dehydrogenases inactivation led to decrease metabolism. Thus, comparative transcriptomes among cells grown on fructose of three strains were performed to investigate gene expression profiles based on three biological replicates.
Project description:Clostridium ljungdahlii not only utilizes CO, but also H2 as energy source during autotrophic growth. In theory, CO is a more energetically and thermodynamically favourable energy source than H2 in the gas fermentation of C. ljungdahlii. However, how C. ljungdahlii conserves energy for growth and ethanol/acetate formation grown on CO or CO2/H2 is not in great detail. In this study, C. ljungdahlii was fermented on CO and CO2/ H2 at pH 6.0 with 0.1 MPa gas pressure. C. ljungdahlii produced 27 g/L acetate, 9 g/L ethanol, 8 g/L 2,3-butanediol and traces of lactate in the presence of CO as energy source, while it produced 25.8 0.1 g/L acetate, 1.8 0.1 g/L ethanol, 0.7 0.01g/L 2,3-butanediol and trances of lactate in the same fermentation condition using H2 as energy source. Therefore, comparative transcriptomes between cells grown on CO and cells grown on H2/CO2 were performed to investigate gene expression profiles based on three biological replicates.
Project description:Transcriptomic profiles of the acetogen Clostridium ljungdahlii during lithoautotrophic growth with syngas or with H2 and CO2 compared to organoheterotrophic growth with fructose