Genomic analysis uncovers laccase-coding genes and biosynthetic gene clusters encoding antimicrobial compounds in laccase-producing Acinetobacter baumannii

Thermostabilization of a fungal laccase by entrapment in enzymatically synthesized levan nanoparticles

In this work, we present a comprehensive investigation of the entrapment of laccase, a biotechnologically relevant enzyme, into levan-based nanoparticles (LNPs). The entrapment of laccase was achieved concomitantly with the synthesis of LNP, catalyzed by a truncated version of a levansucrase from Leuconostoc mesenteroides. The study aimed to obtain a biocompatible nanomaterial, able to entrap functional laccase, and characterize its physicochemical, kinetic and thermal stability properties. The experimental findings demonstrated that a colloidal stable solution of spherically shaped LNP, with an average diameter of 68 nm, was obtained. An uniform particle size distribution was observed, according to the polydispersity index determined by DLS. When the LNPs synthesis was performed in the presence of laccase, biocatalytically active nanoparticles with a 1.25-fold larger diameter (85 nm) were obtained, and a maximum load of 243 μg laccase per g of nanoparticle was achieved. The catalytic efficiency was 972 and 103 (μM·min)-1, respectively, for free and entrapped laccase. A decrease in kcat values (from 7050 min-1 to 1823 min-1) and an increase in apparent Km (from 7.25 μM to 17.73 μM) was observed for entrapped laccase, compared to the free enzyme. The entrapped laccase exhibited improved thermal stability, retaining 40% activity after 1 h-incubation at 70°C, compared to complete inactivation of free laccase under the same conditions, thereby highlighting the potential of LNPs in preserving enzyme activity under elevated temperatures. The outcomes of this investigation significantly contribute to the field of nanobiotechnology by expanding the applications of laccase and presenting an innovative strategy for enhancing enzyme stability through the utilization of fructan-based nanoparticle entrapments.

Harnessing the power of bacterial laccases for xenobiotic degradation in water: A 10-year overview

Industrialization and population growth are leading to the production of significant amounts of sewage containing hazardous xenobiotic compounds. These compounds pose a threat to human and animal health, as well as the overall ecosystem. To combat this issue, chemical, physical, and biological techniques have been used to remove these contaminants from water bodies affected by human activity. Biotechnological methods have proven effective in utilizing microorganisms and enzymes, particularly laccases, to address this problem. Laccases possess versatile enzymatic characteristics and have shown promise in degrading different xenobiotic compounds found in municipal, industrial, and medical wastewater. Both free enzymes and crude enzyme extracts have demonstrated success in the biotransformation of these compounds. Despite these advancements, the widespread use of laccases for bioremediation and wastewater treatment faces challenges due to the complex composition, high salt concentration, and extreme pH often present in contaminated media. These factors negatively impact protein stability, recovery, and recycling processes, hindering their large-scale application. These issues can be addressed by focusing on large-scale production, resolving operation problems, and utilizing cutting-edge genetic and protein engineering techniques. Additionally, finding novel sources of laccases, understanding their biochemical properties, enhancing their catalytic activity and thermostability, and improving their production processes are crucial steps towards overcoming these limitations. By doing so, enzyme-based biological degradation processes can be improved, resulting in more efficient removal of xenobiotics from water systems. This review summarizes the latest research on bacterial laccases over the past decade. It covers the advancements in identifying their structures, characterizing their biochemical properties, exploring their modes of action, and discovering their potential applications in the biotransformation and bioremediation of xenobiotic pollutants commonly present in water sources.