Biology subjects
Publications and source records attributed to Fernando, E. Y..
Withdrawal StatementThe authors have withdrawn this manuscript because of inaccuracies with funding information. Therefore, the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author.
High cathodic overpotential of the oxygen reduction reaction (ORR) in MFC carbon-based cathodes is one of the key barriers to the widespread adoption of the technology. Current Pt-based ORR catalysts are expensive. The use of novel and inexpensive catalysts as replacements for platinum is therefore desirable. In this study, nanomaterials were directly chemically synthesized on carbon microfiber electrodes to improve the performance of lake sediment inoculated MFCs. Nanomaterial of MnO2, MnO2/polyaniline (PANI), ZnO/NiO and ZnO/NiO/PANI attachments were directly chemically synthesized on the carbon material and used as cathode electrodes. The maximum power densities recorded for the different treatments were; MnO2 78.5 mW/m2, MnO2/PANI (Polyaniline) 141.6 mW/m2, ZnO/NiO 67.6 mW/m2, and ZnO/NiO/PANI 129.4 mW/m2. The current and poswer densities were more than six-fold higher in ZnO/NiO/PANI and MnO2/PANI nanoparticle modified cathodes compared to the control MFCs with no catalyst. Cyclic voltammetry (CV) and FTIR data and SEM images suggest that the nanoparticle attached carbon material is morphologically, chemically and electrochemically different from the controls with no nanomaterial attachment. The outcome of this study demonstrates that nanomaterials-incorporated carbon microfiber cathodes bring about significant enhancements to power densities and may potentially have applications in cost-effective MFCs.
Enhanced biological phosphorus removal (EBPR) is a globally important biotechnological process and relies on the massive accumulation of phosphate within special microorganisms. Candidatus Accumulibacter conform to classical physiology model for polyphosphate accumulating organisms and are widely believed to be the most important player for the process in full-scale EBPR systems. However, it was impossible till now to quantify the contribution of specific microbial clades to EBPR. In this study, we have developed a new tool to directly link the identity of microbial cells to the absolute quantification of intracellular poly-P and other polymers under in situ conditions, and applied it to eight full-scale EBPR plants. Besides Ca. Accumulibacter, members of the genus Tetrasphaera were found to be important microbes for P accumulation, and in six plants they were the most important. As these Tetrasphaera cells did not exhibit the classical phenotype of poly-P accumulating microbes, our entire understanding of the microbiology of the EBPR process has to be revised. Furthermore, our new single-cell approach can now also be applied to quantify storage polymer dynamics in individual populations in situ in other ecosystems and might become a valuable tool for many environmental microbiologists.