Gold structures on 3D carbon electrodes as highly active nanomaterials for the clean energy conversion of crude glycerol

Electrochemical nonenzymatic glucose sensors catalyzed by Au nanoclusters on metallic nanotube arrays and polypyrrole nanowires

Monitoring blood glucose level is critical, since its abnormality leads to diabetes and causes death, even though glucose is essential for human living. Herein, the sensing study was performed on electrochemical nonenzymatic glucose sensors, which are composed of an Au nanocluster (AuNC) catalyst deposited on a metallic nanotube array (MeNTA) and polypyrrole nanowire (PPyNW). The AuNC was produced by irradiating a femtosecond pulse laser to the Au precursor solution, and it is a simple and facile method. The successful deposition of AuNC on both MeNTA and PPyNW was confirmed by means of the surface morphology and the Au content increase. On the exploration by cyclic voltammetry in alkaline condition, AuNC/MeNTA electrodes showed better performance than AuNC/PPyNW electrodes: The former was a remarkable electrocatalytic detector towards glucose oxidation with better sensitivity, lower detection limit, wider linear range, and longer-term stability without interference from potential interfering agents such as ascorbic acid, urea, NaCl, KCl, etc. Moreover, nonenzymatic AuNC/MeNTA electrodes exhibited high precision and accuracy in real human blood samples and, thus, can be a promising candidate in glucose sensing applications.

Improving tolerance and 1,3-propanediol production of Clostridium butyricum using physical mutagenesis, adaptive evolution and genome shuffling

Bioconversion efficiency of glycerol to 1,3-propanediol (1,3-PD) by Clostridium butyricum is bottlenecked by its low tolerance to various stressors, especially glycerol as the substrate, 1,3-PD as the end product, and butyric acid as a by-product, which eventually decreases 1,3-PD yield. This study aimed at improving the tolerance and 1,3-PD production capability of C. butyricum using random mutagenesis and evolutionary techniques. Mutagenesis of wild strain by atmospheric room temperature plasma (ARTP) provided the first population with maximum tolerance to 160 g/L glycerol, while microbial microdroplet culture system (MMC)-mediated adaptive laboratory evolution (ALE) generated the second population with tolerance to 100 g/L 1,3-PD. Subsequently, genome shuffling of both populations yielded a final strain, GJH-418, which generated 60.12 g/L1,3-PD with a productivity of 1.72 g/L/h. The transcript analysis of the mutant and wild strains revealed the possible involvement of 8 genes in high tolerance and high 1,3-PD production through either up- or down-regulation.