Artificial neural network prediction of CO emission and ash yield from co-combustion of empty fruit bunch, palm kernel shell and kaolin.

The quantity of ash yield and carbon monoxide (CO) emitted during co-combustion of empty fruit bunch (EFB), palm kernel shells (PKS) and kaolin in a grate furnace depend on the fuels mixing ratio, the combustion temperature and duration. These factors can be tuned to minimize ash deposition and CO emission which is partly responsible for the greenhouse effect. In this study, seventy-three (73) data points were obtained from combustion of EFB, PKS and kaolin mixtures based on D-optimal design. Artificial neural network (ANN) model, optimized with Taguchi technique, was developed to predict ash yield (AY) and CO emission from the combustion of the fuel mixture. The data were divided into training, validation and testing in a 2:1:1 relative proportion. The optimized ANN architecture for AY and CO emission were 5-11-3-1 and 5-6-3-1, respectively, with scale conjugate gradient training algorithm and a learning rate of 0.1. Results of the ANN model agreed significantly with the experimental results with coefficients of determination (R2) of 0.96 and 0.93 for ash yield and CO emission, respectively. The mathematical models for the ash and CO emission using the D-optimal design indicate a good fit with R2 of 0.916 and 0.906, respectively. Parametric studies based on the two models showed that ash yield and CO emission reduced with increased combustion temperature and increased fraction of PKS within the temperature range of 800-1000 °C. These results indicated that both ANN and D-optimal can be deployed to select mixture with minimal ash yield and CO emission.

Silver-gold alloy nanoparticles biofabricated by fungal xylanases exhibited potent biomedical and catalytic activities.

The search for biocompatible nanoparticles with vast applicability has impacted on exploration of various biomaterials for the synthesis of mono and bimetallic nanoparticles. Xylanase is widely regarded as an industrially important enzyme but its potentials in nanotechnological applications are yet to be fully explored. The current study investigates the exploit of xylanases of Aspergillus niger L3 (NE) and Trichoderma longibrachiatum L2 (TE) produced through valorization of corn-cob, to synthesize silver-gold alloy nanoparticles (Ag-AuNPs). Characterization of the Ag-AuNPs involved UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy and transmission electron microscopy, while their prospective use as antimicrobial, antioxidant, catalytic, anticoagulant, and thrombolytic agents were studied. The biosynthesized Ag-AuNPs were ruby red and light purple with surface plasmon resonance at 520 and 534 nm for NEAg-AuNPs and TEAg-AuNPs, respectively; while FTIR showed that protein molecules capped and stabilized the nanoparticles. The Ag-AuNPs were anisotropic with spherical, oval, and irregular shapes having sizes ranging from 6.98 to 52.51 nm. The nanoparticles appreciably inhibited the growth of tested clinical bacteria (23.40-90.70%) and fungi (70.10-89.05%), and also scavenged 2,2-diphenyl-1-picrylhydrazyl (48.51-53.79%) and hydrogen peroxide (80.5-95.50%). Furthermore, the Ag-AuNPs degraded malachite green (91.39%) and methylene blue (47.10%). Moreover, the Ag-AuNPs displayed outstanding anticoagulant and thrombolytic activities using human blood. This study further emphasizes the significance of xylanases in nanobiotechnology as it has established the potential of xylanases to synthesize Ag-AuNPs, which is being reported for the first time.

Biomedical and Catalytic Applications of Gold and Silver-Gold Alloy Nanoparticles Biosynthesized Using Cell-Free Extract of Bacillus Safensis LAU 13: Antifungal, Dye Degradation, Anti-Coagulant and Thrombolytic Activities.

This study investigated the green biosynthesis of gold (Au) and silver-gold alloy (Ag-Au) nanoparticles using cell-free extract of Bacillus safensis LAU 13 strain (GenBank accession No: KJ461434). The biosynthesized AuNPs and Ag-AuNPs were characterized using UV-Vis spectroscopy, Fourier-transform infrared spectroscopy, and transmission electron microscopy. Evaluation of the antifungal activities, degradation of malachite green, anti-coagulation of blood, and thrombolysis of human blood clot by the biosynthesized nanoparticles were investigated. The AuNPs and Ag-AuNPs had maximum absorbance at 561 and 545 nm, respectively. The FTIR peaks at 3318, 2378, 2114, 1998, 1636, 1287, 446, 421 cm-1 for AuNPs; and 3310, 2345, 2203, 2033, 1636, 1273, 502, 453, 424 cm-1 for Ag-AuNPs indicated that proteins were the capping and stabilization molecules in the biosynthesized nanoparticles. The particles were fairly spherical in shape with size of 10-45 nm for AuNPs and 13-80 nm for Ag-AuNPs. Moreover, energy dispersive X-ray analysis of AuNPs revealed gold as the most prominent metal in the AuNPs solution, while silver and gold were the most prominent in the case of Ag-AuNPs. Selected area electron diffraction showed the biosynthesized nanoparticles as crystal structures with ring shape pattern. AuNPs and Ag-AuNPs displayed growth inhibitions of 66.67-90.78% against strains of Aspergillus fumigatus and A. niger at concentration of 200 µg/ml , and remarkable degradation (> 90%) of malachite green after 48 h. Furthermore, the nanoparticles prevented coagulation of blood, and also completely dissolved blood clots, indicating the biomedical potential of AuNPs and Ag-AuNPs in the management of blood coagulation disorders. This is the first report of the synthesis of AuNPs and Ag-AuNPs using a strain of B. safensis for biomedical and catalytic applications.