Decolorization of remazol brilliant blue R with laccase from Lentinus crinitus grown in agro-industrial by-products

In silico and in vitro assays suggests Congo red dye degradation by a Lentinus sp. laccase enzyme

Laccase is a superfamily of ligninolytic enzymes known to degrade a wide variety of xenobiotics, including synthetic dyes. Congo Red (CR) has a diazo dye function, carcinogenic and mutagenic potential, and is currently applied in clinical analysis. The objective of this work was to produce and characterize the crude extract of Lentinus sp. in semi-solid fermentation (FSS) and perform in vitro and in silico studies to assess the potential of the crude extract to discolor the CR dye. Laccase activity was determined using ABTS as substrate and characterized. The in vitro discoloration was carried out using experimental design 22 at room temperature and monitored at 340 nm for 24h. Molecular docking and molecular dynamics simulations were performed between laccase and CR. The maximum laccase activity production was 29.63 U L-1 with six days of FSS. The optimal temperature and pH were 50 °C and 3.0, respectively. Discoloration of the CR dye was obtained only in tests containing CuSO4. Laccase formed stable complexes with the dye, presenting negative binding energy values ranging from -70.94 to -63.16 kcal mol-1 and the occurrence of seven hydrogen bonds. Molecular dynamics results showed the stability of the system (RMSD ranging from 1.0 to 2.5 Ä) and protein-ligand interaction along simulation. RMSF values pointed residues at the end of chains A (residues 300 to 305, 480 to 500) and B (residues 650 to 655 and 950 to 1000) as the most flexible regions of the laccase. This study highlighted the enzymatic action in the bioremediation of CR in vitro in agreement with the in silico simulations that demonstrate the enzyme potential.Communicated by Ramaswamy H. Sarma.

Activity of Lignin-Modifying Enzyme of Selected Medicinal Mushrooms in Submerged Fermentation of Lignocellulosic Materials

In the present study, wide diversity in the set and activity of lignin-modifying enzymes (LME) was revealed during submerged fermentation of mandarin peel with 15 strains of white rot Basidiomycetes. Among them, Trametes pubescens BCC153 was distinguished by the simultaneous production of laccase, manganese peroxidase (MnP), and lignin peroxidase (LiP). Supplementation of CuSO4 at a concentration of 1 mM in the media for the cultivation of four Trametes species manifold increased the production of laccase. The diverse effects of chemically different lignocellulosic growth substrates and nitrogen sources on the production of individual LME have been established. The maximum laccase activity of T. pubescens was observed when the fungus was cultivated on media containing mandarin peel and wheat bran, whereas the highest MnP and LiP activities were detected in the submerged fermentation of tobacco residue. Peptone and casein hydrolysate appeared to be the best sources of nitrogen to produce laccase and both peroxidases by T. pubescens BCC153 whereas KNO3 was the worst nitrogen-containing compound for the production of all enzymes.

Oxidoreductase enzymes: Characteristics, applications, and challenges as a biocatalyst

Oxidoreductases are enzymes with distinctive characteristics that favor their use in different areas, such as agriculture, environmental management, medicine, and analytical chemistry. Among these enzymes, oxidases, dehydrogenases, peroxidases, and oxygenases are very interesting. Because their substrate diversity, they can be used in different biocatalytic processes by homogeneous and heterogeneous catalysis. Immobilization of these enzymes has favored their use in the solution of different biotechnological problems, with a notable increase in the study and optimization of this technology in the last years. In this review, the main structural and catalytical features of oxidoreductases, their substrate specificity, immobilization, and usage in biocatalytic processes, such as bioconversion, bioremediation, and biosensors obtainment, are presented.

Lentinus crinitus: Traditional use, phytochemical and pharmacological activities, and industrial and biotechnological applications

The saprophytic basidiomycete Lentinus crinitus (L.) Fr is a Brazilian native fungus with pantropical occurrence. L. crinitus produces edible fruiting bodies with medicinal, nutritional, and biotechnological applications. The compounds from fungal fruiting bodies can be applied to the preparation of products in the food, cosmetic, biomedical, and pharmaceutical industries. Our aim was to review the literature on L. crinitus concerning its botanical description, geographical distribution, phytochemistry, pharmacological properties, nutritional value, and biotechnology potential (in vitro cultivation and enzyme production). Scientific search engines, including ScienceDirect, CAPES Journals Portal, Google Scholar, PubMed, SciELO, MEDLINE, LILACS, and SciFinder, were consulted to gather data on L. crinitus. The present review is an up-to-date and comprehensive analysis of the phytochemical compounds, phytopharmacological activities, and biotechnological value of L. crinitus. Extracts from L. crinitus have been reported to exhibit numerous in vitro pharmacological activities such as antioxidant, antifungal, antibacterial, antiviral, and anticancer. The substances in these extracts belong to different classes of chemical compounds such as polysaccharides, fatty acids, terpenes, phenolic acids, and flavonoids. Reviews on Brazilian native fungi are of great importance for scientific knowledge, with great applicability as a mirror for species of the same family. The ethnobotanical, phytochemical, pharmacological, ethnomedicinal, and biotechnological properties of L. crinitus highlighted in this review provide information for future studies and commercial exploitation, and reveal that this fungus has enormous potential for pharmaceutical, nutraceutical, biotechnological, and ecological applications.

Probiotic growth-stimulating capacity and antimicrobial activities of aqueous extracts of Lentinus crinitus (L.) Fr (polyporales, basidiomycota)

Lentinus crinitus (L.) Fr is a wild macrofungus that is popular as antimicrobial and various biological activities. This study aims to determine the capacity growth stimulation of Lactobacillus paracasei and antimicrobial activity of aqueous extracts of L. crinitus obtained from wild basidiomata, mycelial biomass by liquid fermentation and spent mushroom substrate obtained by solid-state fermentation. The antimicrobial activity was investigated against bacterial and fungal pathogens and growth stimulation L. paracasei probiotic bacterium. The total carbohydrate and β-glucan contents of the extracts were determined using colorimetric analysis. The aqueous extracts obtained showed inhibition against Fusarium oxysporum., Penicillium sp., Rhizopus oryzae, Aspergillus niger, Escherichia coli and Salmonella typhimurium. The aqueous extract obtained from wild basidiomata, and mycelial biomass showed the highest percentage of stimulation of L. paracasei growth in 48 h. The extracts obtained from L. crinitus have antimicrobial potential and stimulating capacity of the probiotic Lactobacillus paracasei. Additionally, different biotechnological techniques such as liquid and solid-state fermentation can be used to obtain aqueous extracts.

Biosorption of methylene blue by residue from Lentinus crinitus mushroom cultivation

Conventional textile effluent treatments cannot remove methylene blue, a mutagenic azo dye, and an endocrine disruptor, that remains in the drinking water after conventional water treatment. However, the spent substrate from Lentinus crinitus mushroom cultivation, a waste, could be an attractive alternative to remove persistent azo dyes in water. The objective of this study was to assess the methylene blue biosorption by spent substrate from L. crinitus mushroom cultivation. The spent substrate obtained after mushroom cultivation had been characterized by the point of zero charge, functional groups, thermogravimetric analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. Moreover, the spent substrate biosorption capacity was determined in function of pH, time, and temperature. The spent substrate had a point of zero charge value of 4.3 and biosorbed 99% of methylene blue in pH from 3 to 9, with the highest biosorption in the kinetic assay of 15.92 mg g^- 1, and in the isothermal assay of 120.31 mg g^- 1. Biosorption reached equilibrium at 40 min after mixing and best fitted the pseudo-second-order model. Freundlich model best fitted the isothermal parameters and each 100 g spent substrate biosorbed 12 g dye in an aqueous solution. The spent substrate of L. crinitus cultivation is an effective biosorbent of methylene blue and an alternative to removing this dye from water, adding value to the mushroom production chain, and supporting the circular economy.

Long-term cryopreservation of Lentinus crinitus strains by wheat grain technique

Lentinus crinitus (Basidiomycota: Polyporales) is a saprophytic fungus with biotechnological importance described more than 20 years ago. However, there are few studies on the long-term preservation of this basidiomycete. Cryopreservation is a long-term storage technique that reduces the metabolic activity of microorganisms, but its success depends on the adjustment of the freezing process, the cryoprotectants, and the protective substrates for each species. This study aimed to assess the mycelial viability and genetic stability of L. crinitus strains cryopreserved at -86 °C for two years by the wheat grain technique using different cryoprotectants and freezing methods. Three strains of L. crinitus (U9-1, U13-5, and U15-12) were subjected to different concentrations and types of cryoprotectants (dimethyl sulfoxide, glycerol, glucose, and sucrose), freezing methods such as immediate freezing from 25 to -86 °C and progressing freezing from 25 to -86 °C in a freezing container with isopropyl alcohol to control the rate of cell freezing at -1 °C min^-1, protective substrate (wheat grain and 2% malt extract agar), and cryopreservation period (1, 6, 12, and 24 months). After thawing, samples were evaluated for mycelial viability, time to mycelial recovery, mycelial stability, and genetic stability of the fungus. All techniques achieved effective cryopreservation at -86 °C, mainly with the wheat grain technique. All cryoprotectants (3.5% glycerol, 1.5% dimethyl sulfoxide, 25% sucrose, and 5% glucose), freezing methods (immediate and gradual), and protective substrate (wheat grain and malt extract agar) were effective for cryopreservation of the three L. crinitus strains in an ultra-low temperature freezer for two years. Mycelial viability, mycelial stability, and genetic stability of the fungus were not affected after two-year cryopreservation, evidencing the robustness of the long-term cryopreservation technique and the fungus.

Optimization and kinetic modeling of Trametes maxima IIPLC-32 laccase and application in recalcitrant dye decolorization

Enhanced laccase production by the Trametes maxima fungus and its use for decolorization of the textile dye RBBR.

Decolorization of azo and anthraquinone dyes by crude laccase produced by Lentinus crinitus in solid state cultivation

White-rot basidiomycetes such as Lentinus crinitus produce laccases with potential use in dye biodegradation. However, high productivity and enzymes with specific properties are required in order to make viable laccase production. We aimed to produce laccase from Lentinus crinitus grown in sugarcane bagasse for dye decolorization. Solid state cultivation medium had sugarcane bagasse added with a nutrient solution of 10 g/L glucose, 1 g/L KH₂PO₄, 0.5 g/L MgSO₄, 0.001 g/L FeSO₄, 0.01 g/L ZnSO₄, and 0.01 g/L MnSO₄. The addition of different nitrogen sources (peptone, urea, or peptone plus urea) and different nitrogen concentrations (0, 0.4, 0.6, 0.8, 1.0, and 1.2 g/L) were evaluated. Enzymatic extract was used in the decolorization of azo dyes, reactive blue 220 (RB220) and reactive black 5 (RB5), and anthraquinone dye, Remazol brilliant blue R (RBBR). The greatest laccase activity (4800 U/g dry mass) occurred when the peptone and urea mixture was added to the solid state cultivation medium. When the nitrogen concentration was 1 g/L, the laccase activity increased to 6555 U/g dry mass. The laccase activity peak occurred on the 10th day, and the maximum decolorization within 24 h was observed with enzymatic extracts obtained on different cultivation days, i.e., 6th day for RB220, 10th day for RB5, and 9th day for RBBR. Manganese and lignin peroxidases were not produced when nitrogen was added to the cultivation medium. The crude enzymatic extract was more effective in the decolorization of azo dyes (RB220 and RB5), more than 90% of decolorization, than anthraquinone dye with 77% decolorization.