Cellulose – Carrageenan coated carbon felt as potential anode structure for yeast microbial fuel cell

Anode material is an important part of Microbial Fuel Cells (MFCs). Carrageenan and cellulose are strong candidates for modifying anode due to their many advantages, especially their biocompatibility. Cellulose microfibrils and microcrystalline were trapped on the surface of carbon felt (CF) using carrageenan (KC). The MFC adopted with CF/[KC/CMF] as anodes structures produced a power density of 70.98 mW?m^?2, higher than MFC that used plain CF. The presence of KC changed the CF properties from hydrophobic to hydrophilic. This can be seen from the weight of biofilms formed in CF/KC, CF/[KC/CMC], and CF/[KC/CMF] being 60, 80, and 90 mg, respectively, higher than plain CF (60 mg). Carrageenan was also successful in entrapping cellulose. Cellulose donated hydrogen ions to form oxycellulose, which has a carboxyl group, wherein can increase Direct Electron Transfer (DET) between yeast and the anode. CF/[KC/CMF] anode structure showed excellent performance and has the potential to be developed in the future.     

Effects of the gold nanoparticles including different thiol functional groups on the performances of glucose-oxidase-based glucose sensing devices

Thiol-based self-assembled anchor linked to glucose oxidase (GOx) and gold nanoparticle (GNP) cluster is suggested to enhance the performance of glucose biosensor. By the adoption of thiol-based anchors, the activity of biocatalyst consisting of GOx, GNP, polyethyleneimine (PEI) and carbon nanotube (CNT) is improved because they play a crucial role in preventing the leaching out of GOx. They also promote electron collection and transfer, and this is due to a strong hydrophobic interaction between the active site of GOx and the aromatic ring of anchor, while the effect is optimized with the use of thiophenol anchor due to its simple configuration. Based on that, it is quantified that by the adoption of thiophenol as anchor, the current density of flavin adenine dinucleotide (FAD) redox reaction increases about 42%, electron transfer rate constant (k_s) is 9.1±0.1 s^?1 and the value is 26% higher than that of catalyst that does not use the anchor structure.     

Grafting of cellulose fibers latex by atom transfer radical polymerization

ABSTRACT

This study reported the synthesis of macro-initiator based on microfibers cellulose (MFC) from empty bunches (EFB), which was Ethyl α-bromoisobutyrate. The availability of the hydroxyl group on MFC offered a facile functionalization with Ethyl α-bromoisobutyrate to produce Bromo-ester group on MFC surface (MFC-BiB) that are known to be the excellent initiator for atom transfer radical polymerization (ATRP). As MFC provides only three hydroxyl groups per each unit of glucose with low reactivity, it is crucial to modify MFC with bromide functional groups having reactivity about 10.000 times greater than the hydroxyl group in the MFC. An MFC-BiB macro-initiator was successfully synthesized by homogeneous acetylation of cellulose with Ethyl α-bromoisobutyrate (EBiB) at 40°C. To confirm the performance MFC-BiB as macroinitiator, copolymerization between latex and MFC-BiB was conducted to produce Cellulose-g-latex by ATRP method with bipyridine/CuCl/CuCl₂ ligand as a complex catalyst and toluene/water as a mixed solvent. The degree of MFC-BiB substitution was measured by the FTIR method. The grafting copolymers were characterized by H-NMR and FTIR. The results indicated that the degree of substitution of macro-initiator at the ratio of MFC/EBiB of 1:3 and 1:6 were 1.27 and 1.28, respectively. The grafting efficiency of cellulose backbone with latex via ATRP showed a well-controlled grafting reaction at 44.5%.     

A novel of 2D-3D combination carbon electrode to improve yeast microbial fuel cell performance

Journal of Applied Electrochemistry - This study developed a unique and outstanding 2D-3D anode using an Activated Carbon (AC) or Charcoal Powder (CP) coating on the carbon felt (CF) surface. The...     

Highly sensitive glucose biosensor using new glucose oxidase based biocatalyst

Glucose, which is a primary energy source of living organisms, can induce diabetes or hypoglycemia if its concentration in blood is irregular. It is therefore important to develop glucose biosensor that reads the concentration of glucose in blood precisely. In the present work, we suggest new glucose oxidase (GOx) based catalysts that can improve the sensitivity of the glucose biosensor and make glucose measurements over a wide concentration ranges possible. For synthesizing such catalysts, a composite including pyrenecarboxaldehyde (PCA) and GOx is attached to substrate including carbon nanotube (CNT) and polyethyleneimine (PEI) (CNT/PEI/[PCA/GOx]). Catalytic activity and stability of the catalyst are then evaluated. According to the investigation, the catalyst shows excellent glucose sensitivity of 47.83 μAcm^?2mM^?1, low Michaelis-Menten constant of 2.2 mM, and wide glucose concentration detection, while it has good glucose selectivity against inhibitors, such as uric acid and ascorbic acid. Also, its activity is maintained to 95.7% of its initial value even after four weeks, confirming the catalyst is stable enough. The excellence of the catalyst is attributed to hydrophobic interaction, C=N bonds, and π-hydrogen interaction among GOx, PCA and PEI/CNT. The bindings play a role in facilitating electron transport between GOx and electrode.