Transcriptomic profiles of Clostridium ljungdahlii during lithotrophic growth with syngas or H and CO compared to organotrophic growth with fructose.

Clostridium ljungdahlii derives energy by lithotrophic and organotrophic acetogenesis. C. ljungdahlii was grown organotrophically with fructose and also lithotrophically, either with syngas - a gas mixture containing hydrogen (H), carbon dioxide (CO), and carbon monoxide (CO), or with H and CO.

Correlation between microbial community and granule conductivity in anaerobic bioreactors for brewery wastewater treatment.

Prior investigation of an upflow anaerobic sludge blanket (UASB) reactor treating brewery wastes suggested that direct interspecies electron transfer (DIET) significantly contributed to interspecies electron transfer to methanogens. To investigate DIET in granules further, the electrical conductivity and bacterial community composition of granules in fourteen samples from four different UASB reactors treating brewery wastes were investigated. All of the UASB granules were electrically conductive whereas control granules from ANAMMOX (ANaerobic AMMonium OXidation) reactors and microbial granules from an aerobic bioreactor designed for phosphate removal were not.

Syntrophic growth with direct interspecies electron transfer as the primary mechanism for energy exchange.

Direct interspecies electron transfer (DIET) through biological electrical connections is an alternative to interspecies H2 transfer as a mechanism for electron exchange in syntrophic cultures. However, it has not previously been determined whether electrons received via DIET yield energy to support cell growth. In order to investigate this, co-cultures of Geobacter metallireducens, which can transfer electrons to wild-type G.

When is a microbial culture "pure"? Persistent cryptic contaminant escapes detection even with deep genome sequencing.

Unlabelled: Geobacter sulfurreducens strain KN400 was recovered in previous studies in which a culture of the DL1 strain of G. sulfurreducens served as the inoculum in investigations of microbial current production at low anode potentials (-400 mV versus Ag/AgCl). Differences in the genome sequences of KN400 and DL1 were too great to have arisen from adaptive evolution during growth on the anode.

Transcriptomic and genetic analysis of direct interspecies electron transfer.

The possibility that metatranscriptomic analysis could distinguish between direct interspecies electron transfer (DIET) and H2 interspecies transfer (HIT) in anaerobic communities was investigated by comparing gene transcript abundance in cocultures in which Geobacter sulfurreducens was the electron-accepting partner for either Geobacter metallireducens, which performs DIET, or Pelobacter carbinolicus, which relies on HIT. Transcript abundance for G. sulfurreducens uptake hydrogenase genes was 7-fold lower in cocultures with G.

Bacterial and archaeal communities involved in the in situ degradation of (13) C-labelled straw in the rice rhizosphere.

Rice straw is a major substrate for the production of methane in flooded rice fields and results in increase of CH4 emission into the atmosphere. We investigated the bacteria and archaea involved in straw degradation by adding (13) C-labelled straw to the rhizosphere of planted rice microcosms in the greenhouse. The degradation of added straw resulted in the production of (13) C-labelled CH4 as end-product, which was detected in the pore water.

Effect of nitrogen fertilization on methane oxidation, abundance, community structure, and gene expression of methanotrophs in the rice rhizosphere.

Nitrogen, one of the limiting factors for the yield of rice, can also have an important function in methane oxidation, thus affecting its global budget. Rice microcosms, planted in the greenhouse, were treated with the N-fertilizers urea (UPK) and ammonium sulfate (APK) or were only treated with phosphorous and potassium (PK). Methane oxidation rates in PK and UPK treatments were similar during most of the rice-growing season, revealing no effect of urea.

Activity and composition of methanotrophic bacterial communities in planted rice soil studied by flux measurements, analyses of pmoA gene and stable isotope probing of phospholipid fatty acids.

Methanotrophs in the rhizosphere of rice field ecosystems attenuate the emissions of CH(4) into the atmosphere and thus play an important role for the global cycle of this greenhouse gas. Therefore, we measured the activity and composition of the methanotrophic community in the rhizosphere of rice microcosms. Methane oxidation was determined by measuring the CH(4) flux in the presence and absence of difluoromethane as a specific inhibitor for methane oxidation.