Project description:Clostridium thermocellum is a Gram-positive, anaerobic, thermophilic bacterium that ferments cellulose into ethanol. It is a candidate industrial consolidated bioprocess (CBP) biocatalyst for lignocellulosic bioethanol production to produce bioethanol directly from cellulosic biomass. However, few transcriptomic studies have been reported so far for C. thermocellum using biomass as carbon source. In this study, samples were taken from exponential and stationary phases of C. thermocellum cells growing in MTC media with pretreated switchgrass as carbon source, and transcriptomic profiling change of C. thermocellum during different growth phase was investigated using both expression array and tiling array. This study will help the understanding of gene expression of C. thermocellum using cellulosic biomass as carbon source and the knowledge will facilitate future metabolic engineering effort for strain improvement. [HX12 expression array]: A eleven array study using total RNA recovered from wild-type cultures of Clostridium thermocellum at different growth phase of T2 and T3 with switchgrass as carbon source. Two biological replicates used for each phase. [3Plex tiling array]: A six array study using total RNA recovered from wild-type cultures of Clostridium thermocellum at different growth phase of T2 and T3 with switchgrass as carbon source. Two biological replicates used for each phase.
Project description:The thermophilic anaerobe Clostridium thermocellum is a candidate consolidated bioprocessing (CBP) biocatalyst for cellulosic ethanol production. It expresses enzymes for both cellulose solubilization and its fermentation to produce lignocellulosic ethanol. To gain insights into the C. thermocellum genes, using an updated version of the C. thermocellum ATCC 27405 genome annotation, that are required for specific growth on the cellulosic feedstocks of either pretreated switchgrass or Populus, duplicate fermentations were conducted with a 5 g/L solid substrate loading. High quality RNA was extracted using a method we report for C. thermocellum grown on solid substrates. Transcriptome profiles were obtained at two time points during actively growing fermentations (12 h and 37 h post inoculation). A comparison of two transcriptomic analytical techniques, microarray and RNAseq, was performed and the data analyzed for statistical significance. When thresholds for genes passing significance of FDR>0.05 were applied, microarray (2351 genes) had a greater number of significant genes relative to RNA-seq (280 genes when normalized by KDMM). When a 2-fold difference in expression threshold was applied, seventy-three genes were significantly differentially expressed in common between the two techniques. We identified genes differentially expressed when C. thermocellum ATC 27405 was grown on the two biomass substrates, with two putative efflux/transport systems highly differentially regulated (>5-fold). This study has revealed consistency between these two transcriptomics analytical platforms that gives confidence in our switch from the DNA microarray platform to an RNAseq based platform for routine transcriptomics analyses. To gain insights into the C. thermocellum genes, using an updated version of the C. thermocellum ATCC 27405 genome annotation, that are required for specific growth on the cellulosic feedstocks of either pretreated switchgrass or Populus, duplicate fermentations were conducted with a 5 g/L solid substrate loading. High quality RNA was extracted using a method we report for C. thermocellum grown on solid substrates. Transcriptome profiles were obtained at two time points during actively growing fermentations (12 h and 37 h post inoculation). A comparison of two transcriptomic analytical techniques, microarray and RNAseq, was performed and the data analyzed for statistical significance.
Project description:Clostridium thermocellum is a Gram-positive, anaerobic, thermophilic bacterium that ferments cellulose into ethanol. It is a candidate industrial consolidated bioprocess (CBP) biocatalyst for lignocellulosic bioethanol production to produce bioethanol directly from cellulosic biomass. However, few transcriptomic studies have been reported so far for C. thermocellum using biomass as carbon source. In this study, samples were taken from exponential and stationary phases of C. thermocellum cells growing in MTC media with pretreated switchgrass as carbon source, and transcriptomic profiling change of C. thermocellum during different growth phase was investigated using both expression array and tiling array. This study will help the understanding of gene expression of C. thermocellum using cellulosic biomass as carbon source and the knowledge will facilitate future metabolic engineering effort for strain improvement.