Vilinska ljubav i licemjerje svijeta. Jean Giraudoux, Ondine, 56. dubrovačke ljetne igre

<p><b>Copyright information:</b></p><p>Taken from "Characterization of a filamentous biofilm community established in a cellulose-fed microbial fuel cell"</p><p>http://www.biomedcentral.com/1471-2180/8/6</p><p>BMC Microbiology 2008;8():6-6.</p><p>Published online 10 Jan 2008</p><p>PMCID:PMC2254626.</p><p></p>he anode chamber (mM); closed diamond, propionate in the anode chamber (mM); open triangle, methane in the anode chamber. Methane concentration was expressed as 'mM equivalent (eq.)' by supposing that all methane was present in the aqueous phase. Broken lines represent times when the anode electrode was transferred to new anode chambers, solid stars indicate times when cellulose (6 g l) was added to the anode chambers, while arrows indicate times when pH in the anode chamber was adjusted to 7.0. The arrowhead indicates the time when the cathode chamber was supplemented with potassium ferricyanide

Self-Supporting Oxygen Reduction Electrocatalysts Made from a Nitrogen-Rich Network Polymer

We report the design, synthesis, and evaluation of a new type of non-precious-metal catalyst made from network polymers. 2,6-Diaminopyridine was selected as a building-block monomer for the formation of a nitrogen-rich network polymer that forms self-supporting spherical backbone structures and contains a high density of metal-coordination sites. A Co-/Fe-coordinating pyrolyzed polymer exhibited a high specific oxygen reduction activity with onset and half-wave potentials of 0.87 and 0.76 V vs RHE, respectively, in neutral media. There was no crossover effect of organics on its activity. The power output of a microbial fuel cell equipped with this catalyst on its cathode was more than double the output with a commercial 20 wt % Pt/C catalyst

CpdA is involved in amino acid metabolism in <i>Shewanella oneidensis</i> MR-1

<p>Cyclic 3′,5′-adenosine monophosphate (cAMP) phosphodiesterase (CPD) is an enzyme that catalyzes the hydrolysis of cAMP, a signaling molecule affecting diverse cellular and metabolic processes in bacteria. Some CPDs are also known to function in cAMP-independent manners, while their physiological roles remain largely unknown. Here, we investigated physiological roles of CPD in <i>Shewanella oneidensis</i> MR-1, a model environmental bacterium, and report that CPD is involved in amino-acid metabolism. We found that a CPD-deficient mutant of MR-1 (Δ<i>cpdA</i>) showed decreased expression of genes for the synthesis of methionine, <i>S</i>-adenosylmethionine, and histidine and required these three compounds to grow in minimal media. Interestingly, deletion of adenylate cyclases in Δ<i>cpdA</i> did not restore the ability to grow in minimal media, indicating that the amino acid requirements were not due to the accumulation of cAMP. These results suggest that CPD is involved in the regulation of amino acid metabolism in MR-1 in a cAMP-independent manner.</p> <p>cAMP and cGMP levels and growth rates of cells aerobically grown in lactate minimal medium are shown in panels A, B, and C, respectively.</p

Polarization (open squares) and power (closed squares) curves for the methanol-fed MFC.

<p>Polarization (open squares) and power (closed squares) curves for the methanol-fed MFC.</p

Catabolic pathway for methanol/acetate conversion in the methanol-fed MFC predicted from the metagenome data (A), and phylum-level distributions of genes assigned to each catabolic step (B).

<p>Step I, methanol:THF methyltransferase; II, acetyl-CoA synthase (EC.2.3.1.169); III, carbon monoxide dehydrogenase (EC.1.2.7.4); IV, acetyl-CoA synthetase (EC.6.2.1.1); V, phosphate acetyltransferase (EC.2.3.1.8); and VI, acetate kinase (EC.2.7.2.1).</p

Comparison of the total lengths of large contigs affiliated with different phyla as determined by MEGAN or BLSOM analyses of the metagenome data.

<p>Comparison of the total lengths of large contigs affiliated with different phyla as determined by MEGAN or BLSOM analyses of the metagenome data.</p

Characterization of a filamentous biofilm community established in a cellulose-fed microbial fuel cell-0

<p><b>Copyright information:</b></p><p>Taken from "Characterization of a filamentous biofilm community established in a cellulose-fed microbial fuel cell"</p><p>http://www.biomedcentral.com/1471-2180/8/6</p><p>BMC Microbiology 2008;8():6-6.</p><p>Published online 10 Jan 2008</p><p>PMCID:PMC2254626.</p><p></p>he anode chamber (mM); closed diamond, propionate in the anode chamber (mM); open triangle, methane in the anode chamber. Methane concentration was expressed as 'mM equivalent (eq.)' by supposing that all methane was present in the aqueous phase. Broken lines represent times when the anode electrode was transferred to new anode chambers, solid stars indicate times when cellulose (6 g l) was added to the anode chambers, while arrows indicate times when pH in the anode chamber was adjusted to 7.0. The arrowhead indicates the time when the cathode chamber was supplemented with potassium ferricyanide

Metagenomic Analyses Reveal the Involvement of Syntrophic Consortia in Methanol/Electricity Conversion in Microbial Fuel Cells

<div><p>Methanol is widely used in industrial processes, and as such, is discharged in large quantities in wastewater. Microbial fuel cells (MFCs) have the potential to recover electric energy from organic pollutants in wastewater; however, the use of MFCs to generate electricity from methanol has not been reported. In the present study, we developed single-chamber MFCs that generated electricity from methanol at the maximum power density of 220 mW m⁻² (based on the projected area of the anode). In order to reveal how microbes generate electricity from methanol, pyrosequencing of 16S rRNA-gene amplicons and Illumina shotgun sequencing of metagenome were conducted. The pyrosequencing detected in abundance <i>Dysgonomonas</i>, <i>Sporomusa</i>, and <i>Desulfovibrio</i> in the electrolyte and anode and cathode biofilms, while <i>Geobacter</i> was detected only in the anode biofilm. Based on known physiological properties of these bacteria, it is considered that <i>Sporomusa</i> converts methanol into acetate, which is then utilized by <i>Geobacter</i> to generate electricity. This speculation is supported by results of shotgun metagenomics of the anode-biofilm microbes, which reconstructed relevant catabolic pathways in these bacteria. These results suggest that methanol is anaerobically catabolized by syntrophic bacterial consortia with electrodes as electron acceptors.</p></div

Characterization of a filamentous biofilm community established in a cellulose-fed microbial fuel cell-5

<p><b>Copyright information:</b></p><p>Taken from "Characterization of a filamentous biofilm community established in a cellulose-fed microbial fuel cell"</p><p>http://www.biomedcentral.com/1471-2180/8/6</p><p>BMC Microbiology 2008;8():6-6.</p><p>Published online 10 Jan 2008</p><p>PMCID:PMC2254626.</p><p></p>he anode chamber (mM); closed diamond, propionate in the anode chamber (mM); open triangle, methane in the anode chamber. Methane concentration was expressed as 'mM equivalent (eq.)' by supposing that all methane was present in the aqueous phase. Broken lines represent times when the anode electrode was transferred to new anode chambers, solid stars indicate times when cellulose (6 g l) was added to the anode chambers, while arrows indicate times when pH in the anode chamber was adjusted to 7.0. The arrowhead indicates the time when the cathode chamber was supplemented with potassium ferricyanide

Typical time courses of cell voltage (A), methanol concentration (B), and acetate concentration (C), after supplementation of the MFC with 10 mM methanol.

<p>In panels B and C, data are means ± SD (n = 3), and error bars are shown when they are larger than symbols.</p