Project description:This experiment aim was to characterize the catabolism of L-rhamnose of Clostridium beijerinckii DSM 6423 by transcriptomic analysis, generating new insights and knowledge on utilization of L-rhamnose for production of chemicals, including Isopropanol, Butanol, Ethanol (IBE) and 1,2-propandiol. These analysis on cultures grown on L-rhamnose compared to D-glucose grown cultures showed upregulation of the L-rhamnose-related clusters and genes, and lower expression of the solventogenic genes, which was reflected in the products formed.
Project description:Clostridium thermocellum is a promising CBP candidate organism capable of directly converting lignocellulosic biomass to ethanol. Low yields, productivities and growth inhibition prevent industrial deployment of this organism for commodity fuel production. Symptoms of potential redox imbalance such as incomplete substrate utilization, and fermentation products characteristic of overflow metabolism, have been observed during growth. This perceived redox imbalance may be in part responsible for the mentioned bioproductivity limitations. Toward better understanding the redox metabolism of C. thermocellum, we analyzed gene expression, using microarrays, during addition of two stress chemicals (methyl viologen and hydrogen peroxide) which we observed to change fermentation redox potential.
Project description:Differential RNA-Seq analyses to investigate the basis for metabolic inhibition of Clostridium thermocellum M1570 by xylose. The M1570 strain was developed in the C. thermocellum DSM 1313 Δhpt background strain. Lactate dehydrogenase (Ldh) and phosphotransacetylase (Pta) genes are deleted (Argyros DA, Tripathi SA, Barrett TF, Rogers SR, Feinberg LF, Olson DG, Foden JM, Miller BB, Lynd LR, Hogsett DA, Caiazza NC: High ethanol titers from cellulose by using metabolically engineered thermophilic, anaerobic microbes. Appl Environ Microbiol 2010, 77:8288-8294 )
Project description:Investigation of whole genome gene expression level changes in Lactococcus lactis KCTC 3769T,L. raffinolactis DSM 20443T, L. plantarum DSM 20686T, L. fujiensis JSM 16395T, L. garvieae KCTC 3772T, L. piscium DSM 6634T and L. chungangensis CAU 28T . This proves that transcriptional profiling can facilitate in elucidating the genetic distance between closely related strains.
Project description:Investigation of sulfur metabolism in Clostridium thermocellum DSM 1313 ∆hpt, to determine growth and gene expression when the organism is incubated with either the oxidized (i.e., sulfate) or the reduced and assimilated (i.e., cysteine) forms of sulfur. A sulfite reductase (∆hpt ∆SO3R) knockout mutant to limit sulfur assimilation was created to compare the resulting gene expression patterns by RNAseq transciptomics against the parental strain (∆hpt) when both are grown in the presence of sulfate. Additionally, we bypass the sulfate auxotrophy of the mutant by providing assimilated sulfur in the form of cysteine to determine whether growth is restored to normal and whether methionine can be biosynthesized by yet uncharacterized pathways in this organism.