Evaluation of laccase production by Ganoderma lucidum in submerged and solid-state fermentation using different inducers.

Laccases are multicopper oxidases with high potential for industrial applications. Several basidiomycete fungi are natural producers of this enzyme; however, the optimization of production and selection of inducers for increased productivity coupled with low costs is necessary. Lignocellulosic residues are important lignin sources and potential inducers for laccase production. Pinus taeda, a dominant source of wood-based products, has not been investigated for this purpose yet. The aim of this study was to evaluate the production of laccase by the basidiomycete fungus Ganoderma lucidum in the presence of different inducers in submerged and solid-state fermentation. The results of submerged fermentation in presence of 5 µM CuSO 4 , 2 mM ferulic acid, 0.1 g/L P. taeda sawdust, or 0.05 g/L Kraft lignin indicated that although all the tested inducers promoted increase in laccase activity in specific periods of time, the presence of 2 mM ferulic acid resulted in the highest value of laccase activity (49 U/L). Considering the submerged fermentation, experimental design following the Plackett-Burman method showed that the concentrations of ferulic acid and P. taeda sawdust had a significant influence on the laccase activity. The highest value of 785 U/L of laccase activity on submerged fermentation was obtained on the seventh day of cultivation. Finally, solid-state fermentation cultures in P. taeda using ferulic acid or CuSO 4 as inducers resulted in enzymatic activities of 144.62 and 149.89 U/g, respectively, confirming the potential of this approach for laccase production by G. lucidum.

Thermal and chemical characterization of Dicksonia sellowiana extract by means of thermal analysis

Abstract Dicksonia sellowiana Hook., Dicksoniaceae, is a tree-fern which is being recently used in medicine mainly for its phytotherapic activities. While several other studies have focused on D. sellowiana extract characterization in terms of its biological and antioxidant activity, the novelty of this work aims to understand the fate of this extract during thermal disposal through thermogravimetry/differential thermal analysis, thermogravimetry/mass spectrometry, Fourier transform infrared spectroscopy and elemental analysis, to further characterize this plant's extract. Thermal analysis revealed mass loss within three well-defined steps, with the respective mass signals represented generated during heating. Light-volatiles were released during the first step, with release of NO2, CO2, and ethanol in the following, as a result of extract pyrolytic decomposition. Furthermore, mass signals variation during heating indicated the release of harmless by products in contrast to other pharmaceutical and personal care products. Finally, chemical characterization confirmed the observed under thermal analysis suggesting a highly polar structure within extract's composition.