Versatile Peroxidase Research Articles

Oxidation of sulfonamide micropollutants by versatile peroxidase from Bjerkandera adusta

The oxidation of five sulfonamide antibiotics by the versatile peroxidase (VP, EC. 1.11.1.16) from Bjerkandera adusta was quantitatively assessed. The biocatalytic activity of the enzyme was studied by assaying different reaction conditions. Conversion levels were higher than 90 % for all five sulfonamide antibiotics in the model reaction system. In addition, the enzyme performance was also studied in treated wastewater effluents, where three sulfonamide antibiotics were oxidized at a higher level (greater than 85 % oxidation) and two were oxidized at a lower level (up to 50 %). The identified reaction products for two antibiotics, sulfasalazine, and sulfamethoxazole, showed higher antimicrobial activity than the parental compounds. Docking analyses exhibited that the reaction products interacted with the catalytic pocket of the dihydropteroate synthase from Escherichia coli, similar to the parental antibiotics. Though the oxidation is carried out at high velocity and conversion rates, the application of VP in the enzymatic oxidation technology of sulfonamide antibiotics must overcome the production of more toxic products.

Potential of lignocellulolytic biocatalysts of native and proposed genetically engineered microbial cell factories on jute fiber modification and jute waste recycling: A review

The lignocellulolytic microbial systems from different parts of the world responsible for lignocellulosic biomass (LCB) like jute (Corchorus spp.) waste degradation, fiber modification, and bioenergy production are not limited to a specific prokaryotic or eukaryotic group. The industrial applications of these highly efficient bacterial, fungal and algal communities are related to the production of lignocellulolytic enzymes such as cellulase, hemicellulase, lignin-peroxidase, versatile peroxidase, laccase, thermostable oxidants, pectinase, etc. They are a blessing for the jute, dye, paper, pulp, and biofuel industries as they help to generate a sustainable ecosystem. The jute plant is lignocellulosic biomass so it can be utilized in various ways, from everyday goods to power generation. Jute industries generally use different physicochemical strategies to generate quality fiber and post-retting activities, but these approaches cannot produce desired products; hence microbial routes are best for quality fiber generation, waste remediation, and biofuel generation. To this end, this review summarizes the most important milestones of the development of the leading enzyme-producing cell factories and their engineering by genetic, metabolic, and synthetic biology approaches with the emergence of high throughput methods, such as site-directed mutagenesis and others that can analyze the relevant mutations to accelerate our understanding of lignocellulolytic enzymology.

Bioremoval and Detoxification of the Anticancer Drug Mitoxantrone Using Immobilized Crude Versatile Peroxidase (icVP/Ba) Bjerkandera adusta CCBAS 930.

The aim of this study was to evaluate the biodecolorization and detoxification of the anticancer drug mitoxantron (MTX) by immobilized crude versatile peroxidase of Bjerkandera adusta CCBAS 930 (icVP/Ba). The concentrated crude VP was obtained from B. adusta CCBAS 930 culture on medium with MTX (µg/mL) addition, immobilized with 4% sodium alginate. MTX removal degree (decolorization), levels of phenolic compounds and free radicals were determined during MTX biotransformation. Moreover, the phytotoxicity (Lepidium sativum L.), biotoxicity (multi-species microbial assay, MARA), and genotoxicity (SOS Chromotest) of MTX were evaluated before and after the biological treatment. The use of icVP/Ba (95 U/mL) significantly shortened the bioremoval of 10 µg/mL MTX (95.57% after 72 h). MTX removal by icVP/Ba was correlated with an 85% and 90% decrease in the levels of phenolic compounds and free radicals, respectively. In addition, the use of icVP/Ba contributed to a decrease in the phyto-, bio-, and genotoxicity of MTX. This is the first study to describe the possibility of removing MTX using immobilized crude fungal peroxidase.

Degradation of Polycyclic Aromatic Hydrocarbons by Co-Culture of Pleurotus ostreatus Florida and Azospirillum brasilense

Bacterial-fungal interactions are important in the functioning of natural ecosystems. We examined possible synergistic or antagonistic effects during the degradation of polycyclic aromatic hydrocarbons (PAHs) by a fungal–bacterial co-culture. Bacteria and fungi were grown in a liquid nutrient medium supplemented with PAH substrates. The degradation of PAHs and the identification of metabolites were checked by HPLC. Enzyme activities were spectrophotometrically measured with test substrates. Compared to monocultures, the co-culture yielded higher mycelium dry weights and higher numbers of bacterial colony-forming units (CFUs). Both organisms and their co-culture transformed three- and four-ring PAHs into the corresponding quinones. The degradation of PAHs was accompanied by the production of fungal extracellular laccase and versatile peroxidase, whose activities were higher in the co-culture than they were in the monocultures. The presence of exogenous indole-3-acetic acid (IAA) boosted PAH degradation and enzyme production. The xylotrophic basidiomycete Pleurotus ostreatus Florida and the plant-growth-promoting rhizobacterium Azospirillum brasilense exerted a positive mutual effect, including increases in mycelium dry weight, number of CFUs, degradation of PAHs, and production of fungal extracellular enzymes. IAA may be a factor in the interactions of P. ostreatus Florida with A. brasilense.

Characteristics of new anthraquinone derivative-decolorizing versatile peroxidase produced by Bjerkandera adusta strain CCBAS 930

The aim of the study was to purify and characterize a peroxidase synthesized by the B. adusta strain CCBAS 930. Moreover, optimal pH and temperature, substrate specificity (2,2′-azino-bis(3-ethylben-zothiazoline-6-sulfonate (ABTS), veratryl alcohol (VA), guaiacol (GA), o-dianisidine, 2,6-dimetoxyphenol (2,6-DMP), 2-methoxy-1,4-benzohydroquinone (MBQH2), 2,6-Dimethoxy-1,4-benzohydroquinone (DBQH2)) and the influence of different ions (Al3+, Mn2+, Mg2+, Ca2+, Cu2+, Fe2+, Co2+, Ag2+, Cd2+, Hg2+, and K+ and organic solvents (ethanol, methanol, DMSO, ethyl acetate, n-hexane, diethyl ether, and dichloromethane) on VP/Ba activity were determined. The purified VP/Ba had an RZ value (A407/A280) of 1.85, 45 kDa and an N-terminal sequence VTXPGKVNVVENSA. The catalytic activity of VP/Ba measured by the oxidation of 2,6-DMP with/without Mn2+ was noted at optimum temperature values of 50 °C and 55 °C, respectively. After 24h incubation in different pH conditions (pH = 3.0–7.0), residual VP/Ba activity ranging from 30 to 50% with the optimum at pH = 5.5 (50%) was observed. All the seven substrates tested were oxidized by purified VP/Ba, but the oxidation ratio of 2,6-DMP, VA, GA, and o-dianisidine in the presence of Mn2+ was higher. The highest activity of VP/Ba was detected in the presence of 0.1 mM Al3+, Cu2+, Ca2+, and Mn2+ ions (126%–176%), while Ag2+, Hg2+, Ni+, and K+ at all the concentrations tested (5, 1, and 0.1 mM) significantly decreased its activity. Organic solvents e.g. ethanol, methanol, DMSO, ethyl acetate, n-hexane, diethyl ether, and dichloromethane, partially decreased the activities of VP/Ba measured without and with Mn2+, with residual activities ranging from 10.33% to 69.16% and from 50% to 68.75%, respectively.

Artificial microbial consortium producing oxidases enhanced the biotransformation efficiencies of multi-antibiotics

Antibiotic mixtures in the environment result in the development of bacterial strains with resistance against multiple antibiotics. Oxidases are versatile that can bio-remove antibiotics. Various laccases (LACs), manganese peroxidases (MNPs), and versatile peroxidase (VP) were reconstructed in Pichia pastoris. For the single antibiotics, over 95.0% sulfamethoxazole within 48 h, tetracycline, oxytetracycline, and norfloxacin within 96 h were bio-removed by recombinant VP with α-signal peptide, respectively. In a mixture of the four antibiotics, 80.2% tetracycline and 95.6% oxytetracycline were bio-removed by recombinant MNP2 with native signal peptide (NSP) within 8 h, whereas < 80.0% sulfamethoxazole was bio-removed within 72 h, indicating that signal peptides significantly impacted removal efficiencies of antibiotic mixtures. Regarding mediators for LACs, 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) resulted in better removal efficiencies of multi-antibiotic mixtures than 1-hydroxybenzotriazole or syringaldehyde. Furthermore, artificial microbial consortia (AMC) producing LAC2 and MNP2 with NSP significantly improved bio-removal efficiency of sulfamethoxazole (95.5%) in four-antibiotic mixtures within 48 h. Tetracycline and oxytetracycline were completely bio-removed by AMC within 48 and 72 h, respectively, indicating that AMC accelerated sulfamethoxazole, tetracycline, and oxytetracycline bio-removals. Additionally, transformation pathways of each antibiotic by recombinant oxidases were proposed. Taken together, this work provides a new strategy to simultaneously remove antibiotic mixtures by AMC.

From pomiculture waste to biotechnological raw material: efficient transformation using ligninosomes and cellulosomes from Pleurotus spp.

The goal of this study was to determine the capacity of Pleurotus spp. lignocellulosome to transform frequent pomiculture residues (grapevine-, plum-, and raspberry sawdust) into raw materials for biotechnological processes. All three lignocellulosics induced the synthesis of ligninolytic and cellulolytic enzymes in the tested species. Laccase was dominant in the ligninolytic cocktail, with a maximum activity of 40,494.88 U L−1 observed after the cultivation of P. pulmonarius on grapevine sawdust. Grapevine sawdust also proved to be the optimal substrate for the synthesis of versatile peroxidases especially in P. eryngii (1010.10 U L−1), while raspberry sawdust favored the production of Mn-dependent peroxidase in P. pulmonarius (479.17 U L−1). P. pulmonarius was the dominant cellulolytic agent and raspberry sawdust was optimal for the synthesis of xylanases, and endo- and exo-cellulases (15,746.35 U L−1, 9741.56 U L−1, and 836.62 U L−1), while grapevine sawdust mostly induced β-glucosidase activity (166.11 U L−1). The degree of residues delignification was more substrate- than species-dependent, ranging between 6.44 and 23.72% after the fermentation of grapevine and raspberry sawdust with P. pulmonarius. On the other hand, the lowest level of cellulose consumption was also observed on raspberry sawdust after the cultivation of P. eryngii, which together with high delignification also induced the highest selectivity index (1.27). The obtained results show the exceptional lignocellulolytic potential of Pleurotus spp. enzyme cocktails which opens up many possibilities for their application in numerous biotechnological processes.Graphical

Influence of carbon, nitrogen sources, inducers, and substrates on lignocellulolytic enzyme activities of Morchella spongiola

The influence of various carbon, nitrogen sources, inducers, and different agro-wastes on the growth and ligninolytic enzyme activities of Morchella spongiola (MR17) was studied. This fungus has grown well in mineral salts broth containing mannitol as the carbon and yeast extract as the nitrogen sources. In presence of inducers, the growth was inhibited compared to control. The carbon and nitrogen sources and the inducers affected the laccase activity of M. spongiola . Rhamnose and galactose supported the laccase activity more than other carbon sources tested. The manganese peroxidase (MnP) and versatile peroxidase (VP) activities were not detected in the medium amended with different carbon and nitrogen sources. The inducers, ABTS, and veratryl alcohol enhanced the laccase activity more than others. The MnP activity was maximum in wheat straw, followed by rice straw and phenol red. Maximum VP activity was observed in wheat straw, and rice straw, followed by veratryl alcohol. The protein content increased significantly in groundnuts shell and wheat grain substrates inoculated with M. spongiola . Wheat grains and wheat bran served as the most promising substrates with maximum lignocellulolytic activity. The laccase activity was higher in wheat grains and wheat bran, while VP and MnP activities were higher in rice straw and wheat straw. The cellulase activity was much less compared to other enzyme activities in all the substrates. Maximum lignin degradation was observed in wheat straw, followed by wheat bran. The cellulose degradation was significantly higher in groundnuts shell compared to other substrates. The present study results suggest that M. spongiola can utilize these substrates, induce enzyme activities, and have the potential for mushroom cultivation.

Stable and Functionally Diverse Versatile Peroxidases Designed Directly from Sequences.

White-rot fungi secrete a repertoire of high-redox potential oxidoreductases to efficiently decompose lignin. Of these enzymes, versatile peroxidases (VPs) are the most promiscuous biocatalysts. VPs are attractive enzymes for research and industrial use but their recombinant production is extremely challenging. To date, only a single VP has been structurally characterized and optimized for recombinant functional expression, stability, and activity. Computational enzyme optimization methods can be applied to many enzymes in parallel but they require accurate structures. Here, we demonstrate that model structures computed by deep-learning-based ab initio structure prediction methods are reliable starting points for one-shot PROSS stability-design calculations. Four designed VPs encoding as many as 43 mutations relative to the wildtype enzymes are functionally expressed in yeast, whereas their wildtype parents are not. Three of these designs exhibit substantial and useful diversity in their reactivity profiles and tolerance to environmental conditions. The reliability of the new generation of structure predictors and design methods increases the scale and scope of computational enzyme optimization, enabling efficient discovery and exploitation of the functional diversity in natural enzyme families directly from genomic databases.

Application of ESI FT-ICR MS to Study Kraft Lignin Modification by the Exoenzymes of the White Rot Basidiomycete Fungus TrametesHirsutaLE-BIN 072

Trameteshirsuta is a wood rotting fungus that possesses a vast array of lignin degrading enzymes, including7 laccases, 7 ligninolyticmanganese peroxidases, 9 lignin peroxidases and 2 versatile peroxidases. In this study,electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS)was used to examine kraft lignin modification by the enzymatic system of this fungus.The observed pattern of lignin modification suggested that before the 6th day of cultivation,the fungal enzymatic system tended to degrade more oxidized moleculesand, hence, less recalcitrant molecules, with the production of hard-to-modify reduced molecular species. At some point after the 6th day of cultivation,the fungal enzymatic system tended to degrade more oxidized moleculesand, hence, less recalcitrant molecules, with the production of hard-to-modify reduced molecular species. At some point after the 6th day of cultivation,the fungus started to degrade less oxidized, more recalcitrant, compounds, converting them into the more oxidized forms. The altered pattern of lignin modification enabled changes in the fungal enzymatic system. These changes were further attributed to the appearance of the particular ligninolyticmanganese peroxides enzyme(MnP7), which was added by the fungus to the mixture of enzymes that had already been secreted (VP2 and MnP5).&#x0D; Keywords: wood rotting fungi, kraft lignin, mass spectrometry, peroxidases

Ligninolytic enzymes in Basidiomycetes and their application in xenobiotics degradation

Variety of microorganisms have already proven their capabilities for degradation of wide range of wastes with anthropogenic nature. These pollutants, both liquid and solids, also include so called xenobiotics like phenol and its derivatives, PAHs, dyes, pesticides, pharmaceuticals, etc. Xenobiotics as bisphenol A (BPA), chlorhexidine (CHX), octenidine (OCT), other disinfectants and antiseptics have high ecotoxicological impact. Moreover, they can also impair our quality of life and our health interfering different metabolic and hormone receptors pathways in human body. Chemical treatment of such wastes is not a viable option because of its poor socio-economics and environmental merits. Therefore, applying effective, ecofriendly and cheap treatment methods is of great importance. Basidiomycetes are extensively investigated for their abilities to degrade numerous pollutants and xenobiotics. Through their extracellular ligninolytic enzymes they are capable of reducing or completely removing wide range of hazardous compounds. These enzymes can be categorized in two groups: oxidases (laccase) and peroxidases (manganese peroxidase, lignin peroxidase, versatile peroxidase). Due to the broad substrate specificity of the secreted enzymes Basidiomycetes can be applied as a powerful tool for bioremediation of diverse xenobiotics and recalcitrant compounds.

Catabolic profiling of selective enzymes in the saccharification of non-food lignocellulose parts of biomass into functional edible sugars and bioenergy: An in silico bioprospecting.

Objectives:The research aims to analyze the catabolic strength of different hydrolytic enzymes in assessing the biological conversion potential of lignocellulose parts of agricultural biomass wastes into functional edible sugars and biofuels.Materials and Methods:The enzymes’ hydrolytic properties—versatile peroxidase, manganese peroxidase, and lignin peroxidase were used to identify their complexing strength with the lignin substrate, whereas endoglucanase cel12A, acidocaldarius cellulase, and Melanocarpus albomyces endoglucanase were tested on the cellulose gel substrate. Because the biodegradation properties are heavily influenced by the “enzyme-substrate complexing energy level,” proper molecular optimization and energy minimization of the enzymes and substrates were carried out, as well as the identification of the enzyme’s active sites prior to complexing.comprehensive molecular dynamic simulation was run to study their—alpha carbon, root-mean-square deviation (Å), molecular surface area (Å2), root-mean-square fluctuation (Å), radius of gyration (nm), hydrogen bonds with hydrophobic interactions, and solvent accessible surface area (Å2) values for 50 ns. The simulated data mining was conducted using advanced programming algorithms to establish the final enzyme-substrate complexing strength in binding and catalysis.Results:Among the lignin-degrading enzymes, versatile peroxidase shows promising catalytic activity with the best docking pose and significant values in all the dynamic simulation parameters. Similarly, Melanocarpus albomyces endoglucanase shows the best activity in all aspects of molecular docking and dynamics among the cellulose-degrading enzymes.Conclusion:The lignin content of biomass wastes can be degraded into cellulose and hemicellulose using lignin-degrading enzymes. The cellulose can be further degraded into glucose and xylose sugars following the cellulose-degrading enzyme activity. These sugars can be further degraded into biofuel through anaerobic fermentation. Systematic bioconversion of the lignocellulosic components can ensure sustainable biomass management, creating an alternative food and energy source for human beings to face the challenges of global hunger where the enzymes can pave the way.

Optimized process for the production of fungal peroxidases and efficient saccharification of pre-treated rice straw

Lignin is the most abundant natural source of aromatic polymers in plants. it prevents access to the underlying polymers of cellulose, hemicellulose/xylan for saccharification. Chemical pretreatment methods to remove this lignin barrier have their limitations such as corrosion of equipment, high capital costs, and environmental pollution due to emission of greenhouse gases. As an alternative, lignin modifying enzymes (LME) are being widely tested for delignification. While laccases are proven to break the lignin structure by attacking the phenolic bonds, additional enzymes to break bonds between non-phenolic units are needed. These reactions are commonly mediated by peroxidases such as Lignin peroxidases (LiP) and Versatile peroxidases (VP). Very limited data is available related to production of these very important peroxidases. In the current study, we present efficient production of these peroxidases from a white-rot fungi Pleurotus ostreatus and an optimized pre-treatment process showing an improvement of 20–25% cellulose to glucose conversion efficiency.

LIGNOCELLULOSE WASTE VALORIZATION BY AN ENZYMATIC COCKTAIL OF P. ERYNGII AND P. PULMONARIUS

The present study aimed to characterize Pleurotus eryngii and P. pulmonarius ligninolytic enzymes and to determine their potential for polymer degradation in common agroforestry residues. The peak of laccase activity (36052.33 U L-1) was observed after P. pulmonarius cultivation on oak sawdust. The maximal Mn-dependent peroxidase activity was reached by P. eryngii (2511.36 U L-1), while the highest level of versatile peroxidase activity was noted in P. pulmonarius (3053.03 U L-1), after fermentation of corn stalks. The highest level of lignin loss (46.28%) was achieved after cultivation of P. pulmonarius on corn stalks, but the most selective degradation of lignocellulose polymers was observed after P. eryngii cultivation on wheat straw. The obtained results lead to the conclusion that the studied P. eryngii and P. pulmonarius strains are good producers of ligninolytic enzymes and effective and selective depolymerizers of agroforestry residues, and therefore their use would be beneficial in numerous environmentally friendly technologies.

Engineering the Oleaginous Yeast Rhodosporidium toruloides for Improved Resistance Against Inhibitors in Biomass Hydrolysates.

Conversion of lignocellulosic biomass into lipids and related chemicals has attracted much attention in the past two decades, and the oleaginous yeast Rhodosporidium toruloides has been widely used in this area. While R. toruloides species naturally have physiological advantages in terms of substrate utilization, lipid accumulation, and inhibitor resistance, reduced lipid production and cell growth are noticed when biomass hydrolysates are used as feedstocks. To improve the robustness of R. toruloides, here, we devised engineered strains by overexpressing genes responsible for phenolic compound degradation. Specifically, gene expression cassettes of the manganese peroxidase gene (MNP) and versatile peroxidase gene (VP) were constructed and integrated into the genome of R. toruloides NP11. A series of engineered strains were evaluated for lipid production in the presence of typical phenolic inhibitors. The results showed that R. toruloides strains with proper expression of MNP or VP indeed grew faster in the presence of vanillin and 5-hydroxymethylfurfural than the parental strain. When cultivated in concentrated mode biomass hydrolysates, the strain VP18 had improved performance as the cell mass and lipid content increased by 30% and 25%, respectively. This study provides more robust oleaginous yeast strains for microbial lipid production from lignocellulosic biomass, and similar efforts may be used to devise more advanced lipid producers.

Enhanced Efficiency of the Removal of Cytostatic Anthracycline Drugs Using Immobilized Mycelium of Bjerkandera adusta CCBAS 930.

The aim of this study was to evaluate the bioremoval of anthracycline antibiotics (daunomycin-DNR, doxorubicin–DOX, and mitoxantrone-MTX) by immobilized mycelium of B. adusta CCBAS 930. The activity of oxidoreductases: versatile peroxidases (VP), superoxide dismutase (SOD), catalase (CAT), and glucose oxidase (GOX), and the levels of phenolic compounds (PhC) and free radicals (SOR) were determined during the biotransformation of anthracyclines by B. adusta strain CCBAS 930. Moreover, the phytotoxicity (Lepidium sativum L.), biotoxicity (MARA assay), and genotoxicity of anthracyclines were evaluated after biological treatment. After 120 h, more than 90% of anthracyclines were removed by the immobilized mycelium of B. adusta CCBAS 930. The effective biotransformation of anthracyclines was correlated with detoxification and reduced genotoxicity.

Functional screening and adaptation of fungal cultures to industrial media for improved delignification of rice straw

Screening and development of industrial process for enzymatic delignification is an option for those industries who want to minimize acids and chlorine containing bleaches, thus minimizing the impact on environment. For commercial applications, it is important to screen fungi producing lignin modifying enzymes (LMEs) and adapting them to industrial media for submerged fermentations. Using functional plate assays and a full factorial design (FFD) approach, an optimal media composition for the highest expression of these LMEs has been achieved in this study. Two fungal strains (Trametes versicolor and Pleurotus ostreatus) were selected for evaluation. SDS PAGE and native gel analysis confirmed the results of screening and submerged culture media optimizations. When rice straw was added as inducer, secretion of additional enzymes other than laccases such as manganese peroxidase (MnP), lignin peroxidases (LiP), and versatile peroxidase (VP) in the cultures has been observed. This paper also demonstrates an improved process of enzymatic pretreatment resulting from a washing step introduced before saccharification (Scheme. 1). Hence, the current study proposes that removal of LMEs by washing helps in improvement of cellulase/hemicellulose depolymerization efficiency.

Isolation of Fungi from a Textile Industry Effluent and the Screening of Their Potential to Degrade Industrial Dyes.

Six fungal strains were isolated from the textile industry effluent in which they naturally occur. Subsequently, the fungal strains were identified and characterized in order to establish their potential decolorizing effect on textile industry effluents. The strains of interest were selected based on their capacity to decolorize azo, indigo, and anthraquinone dyes. Three of the strains were identified as Emmia latemarginata (MAP03, MAP04, and MAP05) and the other three as Mucor circinelloides (MAP01, MAP02, and MAP06), while the efficiency of their decolorization of the dyes was determined on agar plate and in liquid fermentation. All the strains co-metabolized the dyes of interest, generating different levels of dye decolorization. Plate screening for lignin-degrading enzymes showed that the MAP03, MAP04, and MAP05 strains were positive for laccase and the MAP01, MAP02, and MAP06 strains for tyrosinase, while all strains were positive for peroxidase. Based on its decolorization capacity, the Emmia latemarginata (MAP03) strain was selected for the further characterization of its growth kinetics and ligninolytic enzyme production in submerged fermentation under both enzyme induction conditions, involving the addition of Acetyl yellow G (AYG) dye or wheat straw extract, and no-induction condition. The induction conditions promoted a clear inductive effect in all of the ligninolytic enzymes analyzed. The highest level of induced enzyme production was observed with the AYG dye fermentation, corresponding to versatile peroxidase (VP), manganese peroxidase (MnP), and lignin peroxidase (LiP). The present study can be considered the first analysis of the ligninolytic enzyme system of Emmia latemarginata in submerged fermentation under different conditions. Depending on the results of further research, the fungal strains analyzed in the present research may be candidates for further biotechnological research on the decontamination of industrial effluents.

Obtaining Cellulose-Available Raw Materials by Pretreatment of Common Agro-Forestry Residues With Pleurotus spp.

The goals of the present study were to characterize the profile of ligninolytic enzymes in five Pleurotus species and determine their ability to delignify eight common agro-forestry residues. Generally, corn stalks were the optimal inducer of Mn-dependent peroxidase activity, but the activity peak was noted after wheat straw fermentation by P. eryngii (3066.92 U/L). P. florida was the best producer of versatile peroxidase, especially on wheat straw (3028.41 U/L), while apple sawdust induced the highest level of laccase activity in P. ostreatus (49601.82 U/L). Efficiency of the studied enzymes was expressed in terms of substrate dry matter loss, which was more substrate-than species-dependent. Reduction of substrate dry mass ranged between 24.83% in wheat straw and 8.83% in plum sawdust as a result of fermentation with P. florida and P. pulmonarius, respectively. The extent of delignification of the studied substrates was different, ranging from 51.97% after wheat straw fermentation by P. pulmonarius to 4.18% in grapevine sawdust fermented by P. ostreatus. P. pulmonarius was also characterized by the highest cellulose enrichment (6.54) and P. ostreatus by very low one (1.55). The tested biomass is a highly abundant but underutilized source of numerous value-added products, and a cocktail of ligninolytic enzymes of Pleurotus spp. could be useful for its environmentally and economically friendly transformation.

Functional Characterization of Melanin Decolorizing Extracellular Peroxidase of Bjerkandera adusta.

Melanin pigmentation in the human skin results from complicated cellular mechanisms that remain to be entirely understood. Uneven melanin pigmentation has been counteracted by inhibiting synthesis or transfer of melanin in the skin. Recently, an enzymatic approach has been proposed, wherein the melanin in the skin is decolorized using lignin peroxidase. However, not many enzymes are available for decolorizing melanin; the most studied one is lignin peroxidase derived from a lignin degrading fungus, Phanerochaete chrysosporium. Our current study reveals that versatile peroxidase from Bjerkandera adusta can decolorize synthetic melanin. Melanin decolorization was found to be dependent on veratryl alcohol and hydrogen peroxide, but not on Mn2+. The degree of decolorization reached over 40% in 10 min at 37 °C and a pH of 4.5. Optimized storage conditions were slightly different from those for the reaction; crude enzyme preparation was the most stable at 25 °C at pH 5.5. Since the enzyme rapidly lost its activity at 50 °C, stabilizers were screened. As a result, glycerol, a major component in several cosmetic formulations, was found to be a promising excipient. Our results suggest that B. adusta versatile peroxidase can be considered for future cosmetic applications aimed at melanin decolorization.