Enzyme Properties of a Laccase Obtained from the Transcriptome of the Marine-Derived Fungus Stemphylium lucomagnoense

Abstract

Only a few studies have examined how marine-derived fungi and their enzymes adapt to salinity and plant biomass degradation. This work concerns the production and characterisation of an oxidative enzyme identified from the transcriptome of marine-derived fungus Stemphylium lucomagnoense. The laccase-encoding gene SlLac2 from S. lucomagnoense was cloned for heterologous expression in Aspergillus niger D15#26 for protein production in the extracellular medium of around 30 mg L−1. The extracellular recombinant enzyme SlLac2 was successfully produced and purified in three steps protocol: ultrafiltration, anion-exchange chromatography, and size exclusion chromatography, with a final recovery yield of 24%. SlLac2 was characterised by physicochemical properties, kinetic parameters, and ability to oxidise diverse phenolic substrates. We also studied its activity in the presence and absence of sea salt. The molecular mass of SlLac2 was about 75 kDa, consistent with that of most ascomycete fungal laccases. With syringaldazine as substrate, SlLac2 showed an optimal activity at pH 6 and retained nearly 100% of its activity when incubated at 50°C for 180 min. SlLac2 exhibited more than 50% of its activity with 5% wt/vol of sea salt.

Biotransformation of the Fluoroquinolone, Levofloxacin, by the White-Rot Fungus Coriolopsis gallica

“…DyPs have also been applied to degrade human health-hazard molecules such as halophenols [80]. For these reasons, the two classes of enzymes could be promising enzyme targets to be overproduced in a fungal host such as Pichia pastoris [81] or Aspergillus niger [82] and tested for their broad properties in applied biotechnology processes. However, of the five identified enzymes, Laccase 1 of C. gallica was by far the most represented protein in the secretomes, which is coherent with the high laccase activities assayed in the secretomes.…”

Screening New Xylanase Biocatalysts from the Mangrove Soil Diversity

“…There was a similar effect on the terrestrial T. versicolor DyP1, Tv DyP1 [ 6 ]. Likewise, but with a less pronounced effect, a laccase purified from the marine-derived Stemphylium lucomagnoense strain from the Tunisian coast lost 50% of its initial activity in 4% of sea salt [ 38 ]. By contrast, two laccases obtained from Pestalotiopsis sp.…”

Purification, characterization and three-dimensional structure prediction of multicopper oxidase Laccases from Trichoderma lixii FLU1 and Talaromyces pinophilus FLU12

“…Fungal Laccases are glycoproteins which exist as monomer, homodimer, heterodimer, and multimer forms, with four redox-active copper atoms used in oxidizing substrates using oxygen as electron acceptor and its subsequent reduction to form water molecule 21 . The molecular mass and isoelectric point (pl) of Laccases ranges from 50 to 100 kDa and 3–7, respectively 22 . Typical Laccase consists of three Cu centres (Type I, II and III) with UV–vis spectrum absorption between 280 to 610 nm and a shouldering at 330 nm 23 .…”