A Novel Conductometric Urea Biosensor with Improved Analytical Characteristic Based on Recombinant Urease Adsorbed on Nanoparticle of Silicalite

Development of a conductometric biosensor for the urea detection has been reported. It was created using a non-typical method of the recombinant urease immobilization via adsorption on nanoporous particles of silicalite. It should be noted that this biosensor has a number of advantages, such as simple and fast performance, the absence of toxic compounds during biosensor preparation, and high reproducibility (RSD = 5.1 %). The linear range of urea determination by using the biosensor was 0.05–15 mM, and a lower limit of urea detection was 20 μM. The bioselective element was found to be stable for 19 days. The characteristics of recombinant urease-based biomembranes, such as dependence of responses on the protein and ion concentrations, were investigated. It is shown that the developed biosensor can be successfully used for the urea analysis during renal dialysis

Landfill leachate: A promising substrate for microbial fuel cells

Landfill leachate emerges as a promising feedstock for microbial fuel cells (MFCs). In the present investigation, direct air-breathing cathode-based MFCs are fabricated to investigate the maximum open circuit potential from landfill leachate. Three MFCs that have different cathode areas are fabricated and studied for 17 days under open circuit conditions. The maximum open circuit voltage (OCV) of the cell is observed to be as high as 1.29 V which is the highest OCV ever reported in the literature using landfill leachate. The maximum cathode area specific power density achieved in the reactor is 1513 mW m(-2). Further studies are under progress to understand the origin of high OCV obtained from landfill leachate-based MFCs. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved

Recent advances in the development and utilization of modern anode materials for high performance microbial fuel cells

Microbial fuel cells (MFCs) are novel bio-electrochemical device for spontaneous or single step conversion of biomass into electricity, based on the use of metabolic activity of bacteria. The design and use of MFCs has attracted considerable interests because of the potential new opportunities they offer for sustainable production of energy from biodegradable and reused waste materials. However, the associated slow microbial kinetics and costly construction materials has limited a much wider commercial use of the technology. In the past ten years, there has been significant new developments in MFCs which has resulted in several-fold increase in achievable power density. Yet, there is still considerable possibility for further improvement in performance and development of new cost effective materials. This paper comprehensively reviews recent advances in the construction and utilization of novel anodes for MFCs. In particular, it highlights some of the critical roles and functions of anodes in MFCs, strategies available for improving surface areas of anodes, dominant performance of stainless-steel based anode materials, and the emerging benefits of inclusion of nanomaterials. The review also demonstrates that some of the materials are very promising for large scale MFC applications and are likely to replace conventional anodes for the development of next generation MFC systems. The hurdles to the development of commercial MFC technology are also discussed. Furthermore, the future directions in the design and selection of materials for construction and utilization of MFC anodes are highlighted

Low-cost stainless-steel wool anodes modified with polyaniline and polypyrrole for high-performance microbial fuel cells

A conducting polymer coated stainless-steel wool (SS-W) is proposed for use as a low-cost anode for microbial fuel cells (MFCs). When coated with polyaniline (PANi) and polypyrrole (PPy), the pristine SS-W, SS/PANi-W and SS/PPy-W anodes produced maximum current densities of 0.30 +/- 0.04, 0.67 +/- 0.05, 0.56 +/- 0.07 mA cm(-2), respectively, in air-cathode MFCs. Also, based on achieved power density, both SS/PANi-W and SS/PPy-W achieved 0.288 +/- 0.036 mW cm(-2) and 0.187 +/- 0.017 mW cm(-2), respectively, which were superior to 0.127 +/- 0.011 mW cm(-2) obtained with pristine SS-W. Further, in comparison with SS-P based anodes, all SS-W based anodes gave improved power densities under similar experimental conditions by at least 70%. Moreover, the charge transfer resistance of the SS-W was much lower (240 +/- 25 Omega cm(-2)) than for the SS-P (3192 +/- 239 Omega cm(-2)). The j(0(apparent)) values obtained for SS/PANi-W (0.098 +/- 0.007 Omega cm(-2)) and SS/PPy-W (0.036 +/- 0.004 mA cm(-2)) anodes were also much higher than that of the pristine SS-W (0.020 +/- 0.005 mA cm(-2)), as well as than those of all SS-P based anodes. The observed enhancement of the bioelectrocatalytic performances were well supported by physicochemical and electrochemical characterisation