Project description:Methanococcus maripaludis is a methanogenic Archaea that conserves energy from molecular hydrogen to reduce carbon dioxide to methane. Chemostat grown cultures limited for phosphate or leucine were compared to determine the regulatory response to leucine limitation. Keywords: archaea, hydrogen, leucine, phosphate, nutrient limitation, growth rate, methanogen
Project description:Methanococcus maripaludis is a methanogenic Archaea that conserves energy from molecular hydrogen to reduce carbon dioxide to methane. Chemostat grown cultures limited for hydrogen, phosphate, or leucine were compared to determine the regulatory response to hydrogen limitation. This was done by comparing hydrogen limited cultures to both leucine limited and phosphate limited cultures. Slow and rapid growing samples limited for either hydrogen or phosphate were compared to determine the regulatory effects of growth rate. Keywords: archaea, hydrogen, leucine, phosphate, nutrient limitation, growth rate, methanogen
Project description:Our goal is to convert methane efficiently into liquid fuels that may be more readily transported. Since aerobic oxidation of methane is less efficient, we focused on anaerobic processes to capture methane, which are accomplished by anaerobic methanotrophic archaea (ANME) in consortia. However, no pure culture capable of oxidizing and growing on methane anaerobically has been isolated. In this study, Methanosarcina acetivorans, an archaeal methanogen, was metabolically engineered to take up methane, rather than to generate it. To capture methane, we cloned the DNA coding for the enzyme methyl-coenzyme M reductase (Mcr) from an unculturable archaeal organism from a Black Sea mat into M. acetivorans to effectively run methanogenesis in reverse. The engineered strain produces primarily acetate, and our results demonstrate that pure cultures can grow anaerobically on methane. Differential gene analysis of two growth conditions (three biological replicates each) was performed: (i) M. acetivorans/pES1-MATmcr3 grown on methane and (ii) M. acetivorans/pES1-MATmcr3 grown on methanol. All starter cultures (200 mL) were grown on methanol for 5 days, and harvested by centrifugation. Cell pellets were washed three times with HS medium, and resuspended using 5 mL HS medium, 2 µg/mL puromycin, and 0.1 mM FeCl3. For condition (i), methane was filled into the headspace of the cultures. For condition (ii), 150 mM methanol was added. All cultures were incubated at 37C for 5 days, followed by rapid centrifugation in the presence of 50 µL RNAlater solution (Ambion, Austin, TX) per mL of culture. Total RNA was isolated using RNeasy Mini kit (Qiagen, Valencia, CA) were then digested with terminator 5â-phosphate-dependent exonuclease (Epicentre, Madison, WI) to partially remove ribosomal RNA. Digested RNA were cleaned up using AgenCourt RNAClean XP beads (AgenCourt Bioscience, Beverly, MA) and used for cDNA library construction using the TruSeq Stranded mRNA Library kit (Illumina). Pooled and barcoded cDNA library was then sequenced on a HiSeq sequencing platform (Illumina). Obtained reads were mapped to the reference genome of M. acetivorans (Genbank accession NC_003552.1) using STAR. The mapped reads were assembled using Cufflink v2.2.1 to identify potential novel transcripts. Assembled, unannotated novel transcripts for all the strains were combined with the list of known genes. Differential expression of genes and potential novel transcripts were determined using Cuffdiff at a significance cutoff at q < 0.07 with a false discovery rate of 0.05. Expression levels of gene transcripts are expressed as fragments per kilobase of transcript per million mapped fragments (FPKM), and expression changes are determined by the ratio of FPKM of culture replicates grown on methane to FPKM of culture replicates grown on methanol.
Project description:We integrated genomic and transcriptomic analysis of a newly isolated obligate Methylomonas sp. DH-1 grown on methane and methanol. Comparative transcriptomic analysis between methane and methanol as a sole carbon source revealed different transcriptional responses of Methylomonas sp. DH-1, especially in C1 assimilation, the secondary metabolites pathways and the oxidative stress related genes
Project description:Methylomicrobium buryatense 5GB1 is an obligate methylotroph, which grows on methane or methanol with similar growth rates. Core metabolic pathways are similar on both substrates, but recent studies of methane metabolism suggest that growth on methanol might have significant differences from growth on methane. In this study, both a targeted metabolomics approach as well as a 13C tracer approach have been taken to understand core carbon metabolism in M. buryatense 5GB1 during methanol growth, to determine whether such differences occur. Targeted metabolomics analyses were performed on both methane and methanol cultures to identify metabolic nodes with altered fluxes. Several key metabolites showed significant differences in pool size. Noticeably, 2-keto-3-deoxy-6-phosphogluconate (KDPG) showed much larger pools under methanol culture, suggesting the Entner-Doudoroff (ED) pathway was more active. Intermediates in other parts of metabolism also showed differences in pool sizes under methanol growth. A systematic shift of active core metabolism is proposed to explain the changes. In order to distinguish flux partition differences at the C3-C4 node, 13C tracer analysis was also applied to methanol-grown cultures. Using the experimental results as constraints, we applied flux balance analysis to determine the metabolic flux phenotype of M. buryatense 5GB1 growing on methanol. The resulting new insights into core metabolism of this methanotroph provide an improved basis for future strain design.
Project description:Our goal is to convert methane efficiently into liquid fuels that may be more readily transported. Since aerobic oxidation of methane is less efficient, we focused on anaerobic processes to capture methane, which are accomplished by anaerobic methanotrophic archaea (ANME) in consortia. However, no pure culture capable of oxidizing and growing on methane anaerobically has been isolated. In this study, Methanosarcina acetivorans, an archaeal methanogen, was metabolically engineered to take up methane, rather than to generate it. To capture methane, we cloned the DNA coding for the enzyme methyl-coenzyme M reductase (Mcr) from an unculturable archaeal organism from a Black Sea mat into M. acetivorans to effectively run methanogenesis in reverse. The engineered strain produces primarily acetate, and our results demonstrate that pure cultures can grow anaerobically on methane.
2015-12-20 | GSE66445 | GEO
Project description:Enrichment of microflora with fungi and methanogen to produce methane from coal
Project description:Expression profile of wild-type S. ovata and methanol-adapted strain grown autotrophically with H2 as the source of electron. Illumina RNA-Seq of total RNA extracted from a strain of S. ovata evolved by adaptive laboratory evolution to grow faster with methanol 2% as the sole susbtrate and from the wild type. The adapted strain was transfer 18 times on methanol 2%. Total RNA was extracted from both strains growing with H2/CO2.