Characterization, catalytic, and recyclability studies of nano-sized spherical palladium particles synthesized using aqueous poly-extract (turmeric, neem, and tulasi).

Green synthesis of noble metal nanoparticles (NPs) has gained immense significance compared to other metal ions owing to their unique properties. Among them, palladium 'Pd' has been in the spotlight for its stable and superior catalytic activity. This work focuses on the synthesis of Pd NPs using the combined aqueous extract (poly-extract) of turmeric (rhizome), neem (leaves), and tulasi (leaves). The bio-synthesized Pd NPs were characterized to study its physicochemical and morphological features using several analytical techniques. Role of Pd NPs as nano-catalysts in the degradation of dyes (1 mg/2 mL stock solution) was evaluated in the presence of a strong reducing agent (sodium borohydride; SBH). In the presence of Pd NPs and SBH, maximum reduction of methylene blue (MB), methyl orange (MO), and rhodamine-B (Rh-B) dyes was observed under 20nullmin (96.55 ± 2.11%), 36nullmin (96.96 ± 2.24%), and 27nullmin (98.12 ± 1.33%), with degradation rate of 0.1789 ± 0.0273 min-1, 0.0926 ± 0.0102 min-1, and 0.1557 ± 0.0200 min-1, respectively. In combination of dyes (MB + MO + Rh-B), maximum degradation was observed under 50nullmin (95.49 ± 2.56%) with degradation rate of 0.0694 ± 0.0087 min-1. It was observed that degradation was following pseudo-first order reaction kinetics. Furthermore, Pd NPs showed good recyclability up to cycle 5 (72.88 ± 2.32%), cycle 9 (69.11 ± 2.19%) and cycle 6 (66.21 ± 2.72%) for MB, MO and Rh-B dyes, respectively. Whereas, up to cycle 4 (74.67 ± 0.66%) during combination of dyes. As Pd NPs showed good recyclability, they can be used for several cycles thus influencing the overall economics of the process.

Role of metagenomics in prospecting novel endoglucanases, accentuating functional metagenomics approach in second-generation biofuel production: a review.

As the fossil fuel reserves are depleting rapidly, there is a need for alternate fuels to meet the day to day mounting energy demands. As fossil fuel started depleting, a quest for alternate forms of fuel was initiated and biofuel is one of its promising outcomes. First-generation biofuels are made from edible sources like vegetable oils, starch, and sugars. Second-generation biofuels (SGB) are derived from lignocellulosic crops and the third-generation involves algae for biofuel production. Technical challenges in the production of SGB are hampering its commercialization. Advanced molecular technologies like metagenomics can help in the discovery of novel lignocellulosic biomass-degrading enzymes for commercialization and industrial production of SGB. This review discusses the metagenomic outcomes to enlighten the importance of unexplored habitats for novel cellulolytic gene mining. It also emphasizes the potential of different metagenomic approaches to explore the uncultivable cellulose-degrading microbiome as well as cellulolytic enzymes associated with them. This review also includes effective pre-treatment technology and consolidated bioprocessing for efficient biofuel production.

Novel buffalo rumen metagenome derived acidic cellulase Cel-3.1 cloning, characterization, and its application in saccharifying rice straw and corncob biomass.

Lignocellulosic biomass (LCB) is a prominent option for second-generation biofuels production. Cellulase hydrolyses cellulose, a component of LCB by attacking the ß-1,4-glycosidic bonds, thus liberating mono, di, and oligosaccharides, which subsequently, can be converted to biofuel. In this study, a novel cellulase (Cel-3.1) of 1593 bp which encodes a 530 amino acid protein was identified from buffalo rumen metagenomic fosmid library, and functional expression was achieved through transformation into Escherichia coli. The molecular weight was estimated as 58 kDa on SDS-PAGE. Cel-3.1 belongs to glycosyl hydrolase family-5 (GH-5) and is predicted to have 14 α-helices and 15 ß-strands. The optimal temperature and pH for Cel-3.1 were experimentally determined as 5.0 and 50 °C respectively. The synergistic effect of Ca2+ with K+ ions improved Cel-3.1 activity significantly (25%) and 1% Polyethylene Glycol (PEG-400), 1% ß-mercaptoethanol enhanced the relative activity Cel-3.1 by 31.68%, 12.03% respectively. Further, the enzymatic (Cel-3.1) hydrolysis of pretreated rice straw and corncob released 13.41 ± 0.26 mg/mL and 15.04 ± 0.08 mg/mL reducing sugars respectively. High Performance Liquid Chromatography (HPLC), Scanning Electron Microscope (SEM), and Fourier Transformation Infrared spectroscopy (FTIR) analysis revealed the capability of Cel-3.1 for the breakdown and hydrolysis of both rice straw and corncob to generate various fermentable sugars.