Laccases are blue multicopper oxidases, which catalyze the monoelectronic oxidation of a broad spectrum of substrates, for example, ortho- and para-diphenols, polyphenols, aminophenols, and aromatic or aliphatic amines, coupled with a full, four-electron reduction of O₂ to H₂O. Hence, they are capable of degrading lignin and are present abundantly in many white-rot fungi. Laccases decolorize and detoxify the industrial effluents and help in wastewater treatment. They act on both phenolic and nonphenolic lignin-related compounds as well as highly recalcitrant environmental pollutants, and they can be effectively used in paper and pulp industries, textile industries, xenobiotic degradation, and bioremediation and act as biosensors. Recently, laccase has been applied to nanobiotechnology, which is an increasing research field, and catalyzes electron transfer reactions without additional cofactors. Several techniques have been developed for the immobilization of biomolecule such as micropatterning, self-assembled monolayer, and layer-by-layer techniques, which immobilize laccase and preserve their enzymatic activity. In this review, we describe the fungal source of laccases and their application in environment protection.

Eco-friendly silver nanoparticles (AgNPs) were synthesized using a carboxymethylated gum kondagogu (CMGK) as capping and reducing agent by microwave irradiation method. Synthesized AgNPs were analyzed by TEM, showed spherical in shape with an average particle size distribution of 9 ± 2 nm. XRD results showed that the cubic-structured AgNPs with crystallite size of 8.6 nm. The synthesized CMGK capped AgNPs was tested for catalytic activity using hexacyanoferrate(III) in the presence of NaBH₄ and the impacts of catalyst dose and temperature were examined. The synthesized AgNPs demonstrated a huge antibacterial action on both Gram-positive and negative groups of microorganisms with inhibition zone of 23, 25 and 28 mm, respectively, for Bacillus subtilis, Bacillus cereus and Escherichia coli, they showed moderate antibacterial action (zone of inhibition 15 mm) with Pseudomonas aeruginosa. In addition, the ability of the AgNPs scavenging activity with different concentrations was studied using the DPPH radical scavenging.

An actinomycete was isolated from mangrove soil collected from Nellore region of Andhra Pradesh, India, and screened for its ability to produce bioactive compounds. The cultural, morphological, and biochemical characters and 16S rRNA sequencing suggest that the isolated strain is Nocardiopsis alba. The bioactive compounds produced by this strain were purified by column chromatography. The in vitro antioxidant capacity of the isolated compounds (fractions) was estimated and fraction F2 showed very near values to the standard ascorbic acid. The potential fraction obtained by column chromatography was subjected to HPLC for further purification, then this purified fraction F2 was examined by FTIR, NMR, and mass spectroscopy to elucidate its chemical structure. By spectral data, the structure of the isolated compound was predicted as “(Z)-1-((1-hydroxypenta-2,4-dien-1-yl)oxy)anthracene-9,10-dione.”

The Pepper leaves extract acts as a reducing and capping agent in the formation of silver nanoparticles. A UV–Vis spectrum of the aqueous medium containing silver nanoparticles demonstrated a peak at 458nm corresponding to the plasmon absorbance of rapidly synthesized silver nanoparticles that was characterized by UV–Vis spectrophotometer. The morphology and size of the benign silver nanoparticles were carried out by the transmission electron microscope (TEM) and field emission scanning electron microscope (FE-SEM). The sizes of the synthesized silver nanoparticles were found to be in the range of 5–60nm. The structural characteristics of biomolecules hosted silver nanoparticles were studied by X-ray diffraction. The chemical composition of elements present in the solution was determined by energy dispersive spectrum. The FTIR analysis of the nanoparticles indicated the presence of proteins, which may be acting as capping agents around the nanoparticles. This study reports that synthesis is useful to avoid toxic chemicals with adverse effects in medical applications rather than physical and chemical methods