Extracellular Enzymes of the White Rot Fungi

Manganese peroxidases (MnPs), gene family members of white-rot fungi, are necessary extracellular enzymes that degrade lignocellulose and xenobiotic aromatic pollutants. However, very little is known about the diversity and expression patterns of the MnP gene family in white-rot fungi, especially in contrast to laccases. Here, the gene and protein sequences of eight unique MnP genes of T. trogii S0301 were characterized. Based on the characteristics of gene sequence, all TtMnPs here belong to short-type hybrid MnP (type I) with an average protein length of 363 amino acids, 5–6 introns, and the presence of conserved cysteine residues. Furthermore, analysis of MnP activity showed that metal ions (Mn2+ and Cu2+) and static liquid culture significantly influenced MnP activity. A maximum MnP activity (>14.0 U/mL) toward 2,6-DMP was observed in static liquid culture after the addition of Mn2+ (1 mM) or Cu2+ (0.2 or 2 mM). Moreover, qPCR analysis showed that Mn2+ obviously upregulated the Group I MnP subfamily (T_trogii_09901, 09904, 09903, and 09906), while Cu2+ and H2O2, along with changing temperatures, mainly induced the Group II MnP subfamily (T_trogii_11984, 11971, 11985, and 11983), suggesting diverse functions of fungal MnPs in growth and development, stress response, etc. Our studies here systematically analyzed the gene structure, expression, and regulation of the TtMnP gene family in T. trogii, one of the important lignocellulose-degrading fungi, and these results extended our understanding of the diversity of the MnP gene family and helped to improve MnP production and appilications of Trametes strains and other white-rot fungi.

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Comparison of the Ability of Several White-rot Fungi to Biobleach Acacia Oxygen-delignified Kraft Pulp

Asian Journal of Biotechnology and Bioresource Technology ◽

10.9734/ajb2t/2019/v5i330061 ◽

2019 ◽

pp. 1-10

Author(s):

Sitompul Afrida ◽

Toshihiro Watanabe ◽

Yutaka Tamai

Keyword(s):

Kraft Pulp ◽

Extracellular Enzymes ◽

Low Cost ◽

White Rot Fungi ◽

Acacia Mangium ◽

White Rot ◽

Irpex Lacteus ◽

Lentinus Tigrinus

Previous screening analyses demonstrated that the in vivo biobleaching activities of the white-rot fungi Irpex lacteus KB-1.1 and Lentinus tigrinus LP-7 are higher than those of Phanerochaete chrysosporium and Trametes versicolor. The purpose of the current study was to examine the production of extracellular enzymes of these four white-rot fungi grown on three types of low-cost media containing agricultural and forestry waste, and to evaluate the ability of the produced extracellular enzymes to biobleach Acacia oxygen-delignified kraft pulp (A-OKP). The biobleaching activity of extracellular fractions of I. lacteus, L. tigrinus, T. versicolor, and P. chrysosporium cultures was the most pronounced after 3 days of incubation with Acacia mangium wood powder supplemented with rice bran and 1% glucose (WRBG) with resultant Kappa number reduction of 4.4%, 6.7%, 3.3%, and 3.3%, respectively. Therefore, biobleaching ability of I. lacteus and L. tigrinus have been shown to be higher than of T. versicolor and P. chrysosporium, both in vivo and in vitro.

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Biodegradation of lignin

Canadian Journal of Botany ◽

10.1139/b95-351 ◽

1995 ◽

Vol 73 (S1) ◽

pp. 1011-1018 ◽

Cited By ~ 57

Author(s):

Ian D. Reid

Keyword(s):

Lignin Peroxidase ◽

Manganese Peroxidase ◽

Extracellular Enzymes ◽

White Rot Fungi ◽

Wood Decay ◽

Brown Rot ◽

Economic Consequences ◽

White Rot ◽

Lignin Biodegradation ◽

Pulp Bleaching

Lignin is an aromatic polymer forming up to 30% of woody plant tissues, providing rigidity and resistance to biological attack. Because it is insoluble, chemically complex, and lacking in hydrolysable linkages, lignin is a difficult substrate for enzymatic depolymerization. Certain fungi, mostly basidiomycetes, are the only organisms able to extensively biodegrade it; white-rot fungi can completely mineralize lignin, whereas brown-rot fungi merely modify lignin while removing the carbohydrates in wood. Several oxidative and reductive extracellular enzymes (lignin peroxidase, manganese peroxidase, laccase, and cellobiose:quinone oxidoreductase) have been isolated from ligninolytic fungi; the role of these enzymes in lignin biodegradation is being intensively studied. Enzymatic combustion, a process wherein enzymes generate reactive intermediates, but do not directly control the reactions leading to lignin breakdown, has been proposed as the mechanism of lignin biodegradation. The economic consequences of lignin biodegradation include wood decay and the biogeochemical cycling of woody biomass. Efforts are being made to harness the delignifying abilities of white-rot fungi to aid wood and straw pulping and pulp bleaching. These fungi can also be used to degrade a variety of pollutants in wastewaters and soils, to increase the digestibility of lignocellulosics, and possibly to bioconvert lignins to higher value products. Key words: delignification, white-rot fungi, biobleaching, lignin peroxidase, manganese peroxidase, laccase.

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Determination of Lignin Modifying Enzymes from Pleurotus ostreatus and Lentinus squarrosulus

Annual Research & Review in Biology ◽

10.9734/arrb/2021/v36i630388 ◽

2021 ◽

pp. 39-45

Author(s):

S. B. Chuku ◽

E. O. Nwachukwu ◽

I. O. Agbagwa ◽

H. O. Stanley

Keyword(s):

Pleurotus Ostreatus ◽

Large Scale ◽

Extracellular Enzymes ◽

Colour Change ◽

White Rot Fungi ◽

White Rot ◽

Scale Production ◽

Large Scale Production ◽

Physiological Group

Fungi play vital roles as decomposers. White rot fungi are an eco-physiological group that degrades wood by the secretion of specialized extracellular enzymes including lignin-modifying enzymes. There is growing interest in the use of extracellular enzymes for bioremediation. This study determined the Lignin Modifying Enzymes (LMEs) associated with two species of mushroom, Pleurotus ostreatus and Lentinus squarrosulus. The qualitative study was conducted using agar medium substituted with chromogenic substances to determine the production of LMEs by the species. The appearance of colour change and clearance due to reaction with chromogenic substrates were used to determine LMEs production by the fungi. The results showed that Pleurotus ostreatus and Lentinus squarrosulus tested positive by the appearance of light brown colouration, reddish-brown colouration and discolouration of media for overall polyphenol oxidase, Laccase and Peroxidase activity, respectively. The study showed that the species studied are candidates for large scale production of LMEs that can be utilized as an eco-friendly solution for bioremediation of contaminated sites.

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Coupling structural characterization with secretomic analysis reveals mechanism of the disruption of cross-linked structure in bamboo culms by Echinodontium taxodii

10.21203/rs.2.18571/v1 ◽

2019 ◽

Author(s):

Wen Kong ◽

Jialong Zhang ◽

Qiuyun Xiao ◽

Jiashu Liu ◽

Zhixiang Cao ◽

...

Keyword(s):

Lignocellulosic Biomass ◽

Extracellular Enzymes ◽

Early Stage ◽

White Rot Fungi ◽

White Rot ◽

Biomass Recalcitrance ◽

Lignocellulose Conversion ◽

Fungal Pretreatment ◽

Insight Into

Abstract Background: Overcoming the biomass recalcitrance is essential for efficient utilization of lignocellulosic biomass in industrial bio-refining. White-rot fungi can overcome the biomass recalcitrance and accelerate the conversion of lignocellulose to biofuels via a large number of special extracellular lignocellulolytic enzymes. Previous studies try to dissect the function of extracellular enzymes on biomass resistant cross-linked structures by secretome analysis, but the bio-alteration of cross-linked structures is ignored usually. A deeper and detailed understanding of relationship between secretome and bio-alteration of cross-linked structure in lignocellulosic biomass is still lack. Results: As an efficient wood-decaying fungus, Echinodontium taxodii could improve the conversion efficiency of lignocellulose to biofuels. This study coupled comparative analysis of fungal secretomes and 2D HSQC NMR analysis of lignocellulose fractions, aiming to elucidate the role of extracellular enzymes from Echinodontium taxodii 2538 in the disruption of resistant cross-linked structure of bamboo culms. Carboxylesterases, alcohol oxidases and Class-II peroxidases showed importance in the cleavage of cross-linked structures, including ester and ether linkages of lignin-carbohydrate complexes (LCCs) and inter-unit linkages of lignin, which contributed to biomass resistance removal and cellulose exposure during the early stage of fungal decay. Moreover, the rapid oxidation of Cα-OH was found to contribute to the lignin bio-depolymerization. Conclusions: These findings revealed the detailed mechanisms of biomass recalcitrance reduction by fungal pretreatment, and provide insight into efficient strategy of lignocellulose conversion. It will advance the development in design of enzyme cocktail for efficient lignocellulose bio-refinery.

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Dibenzyl Sulfide Metabolism by White Rot Fungi

Applied and Environmental Microbiology ◽

10.1128/aem.69.2.1320-1324.2003 ◽

2003 ◽

Vol 69 (2) ◽

pp. 1320-1324 ◽

Cited By ~ 39

Author(s):

Jonathan D. Van Hamme ◽

Eddie T. Wong ◽

Heather Dettman ◽

Murray R. Gray ◽

Michael A. Pickard

Keyword(s):

Extracellular Enzymes ◽

Laccase Activity ◽

Petroleum Industry ◽

White Rot Fungi ◽

Viscosity Reduction ◽

White Rot ◽

Organosulfur Compounds ◽

Trametes Hirsuta ◽

Dibenzyl Sulfide ◽

Cytochrome P 450

ABSTRACT Microbial metabolism of organosulfur compounds is of interest in the petroleum industry for in-field viscosity reduction and desulfurization. Here, dibenzyl sulfide (DBS) metabolism in white rot fungi was studied. Trametes trogii UAMH 8156, Trametes hirsuta UAMH 8165, Phanerochaete chrysosporium ATCC 24725, Trametes versicolor IFO 30340 (formerly Coriolus sp.), and Tyromyces palustris IFO 30339 all oxidized DBS to dibenzyl sulfoxide prior to oxidation to dibenzyl sulfone. The cytochrome P-450 inhibitor 1-aminobenzotriazole eliminated dibenzyl sulfoxide oxidation. Laccase activity (0.15 U/ml) was detected in the Trametes cultures, and concentrated culture supernatant and pure laccase catalyzed DBS oxidation to dibenzyl sulfoxide more efficiently in the presence of 2,2′-azinobis(3-ethylbenzthiazoline-6-sulfonate) (ABTS) than in its absence. These data suggest that the first oxidation step is catalyzed by extracellular enzymes but that subsequent metabolism is cytochrome P-450 mediated.

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Assessing The Biodegradation of Vulcanised Rubber Particles by Fungi Using Genetic, Molecular and Surface Analysis

10.21203/rs.3.rs-785149/v1 ◽

2021 ◽

Author(s):

Rodrigo Andler ◽

Vivian D’Afonseca ◽

Javiera Pino ◽

Cristian Valdés ◽

Marcela Salazar-Viedma

Keyword(s):

Extracellular Enzymes ◽

Degradation Products ◽

White Rot Fungi ◽

Fungal Species ◽

White Rot ◽

Great Resistance ◽

Rubber Particles ◽

Tyre Waste ◽

Public Repositories ◽

Highly Hydrophobic

Abstract Millions of tonnes of tyre waste are discarded annually and are considered one of the most difficult solid wastes to recycle. A sustainable alternative for the treatment of vulcanised rubber is the use of microorganisms that can biotransform polymers and aromatic compounds and then assimilate and mineralise some of the degradation products. However, vulcanised rubber materials present great resistance to biodegradation due to the presence of highly hydrophobic cross-linked structures that are provided by the additives they contain and the vulcanisation process itself. In this work, the biodegradation capabilities of 10 fungal strains cultivated in PDA and EM solid medium were studied over a period of 4 weeks. The growth of the strains, the mass loss of the vulcanised rubber particles and the surface structure were analysed after the incubation period. With the white rot fungi Trametes versicolor and Pleurotus ostreatus, biodegradation percentages of 7.5 and 6.1%, respectively, were achieved. The FTIR and SEM-EDS analyses confirmed a modification of the abundance of functional groups and elements arranged on the rubber surface, such as C, O, S, Si and Zn, due to the biological treatment employed. The availability of genomic sequences of P. ostreatus and T. versicolor in public repositories allowed the analysis of the genetic content, genomic characteristics and specific components of both fungal species, determining some similarities between both species and their relationship with rubber biodegradation. Both fungi presented a higher number of sequences for laccases and manganese peroxidases, two extracellular enzymes responsible for many of the oxidative reactions reported in the literature. The integrative analysis of the results, supported by genetic and bioinformatics tools, allowed a deeper analysis of the biodegradation processes of vulcanised rubber. It is expected that this type of analysis can be used to find more efficient biotechnological solutions in the future.

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Mycoremediation of Soils Polluted with Trichloroethylene: First Evidence of Pleurotus Genus Effectiveness

Applied Sciences ◽

10.3390/app11041354 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1354

Author(s):

Begoña Mayans ◽

Raquel Camacho-Arévalo ◽

Carlos García-Delgado ◽

Cynthia Alcántara ◽

Norbert Nägele ◽

...

Keyword(s):

Extracellular Enzymes ◽

Sandy Loam ◽

Anaerobic Bacteria ◽

White Rot Fungi ◽

Environmental Pollutant ◽

Sandy Loam Soil ◽

White Rot ◽

Mn Peroxidase ◽

Loam Soil ◽

Industrial Cleaning

Trichloroethylene (TCE) is a proven carcinogenic chlorinated organic compound widely used as a solvent in industrial cleaning solutions; it is easily found in the soil, air, and water and is a hazardous environmental pollutant. Most studies have attempted to remove TCE from air and water using different anaerobic bacteria species. In addition, a few have used white-rot fungi, although there are hardly any in soil. The objective of the present work is to assess TCE removal efficiency using two species of the genus Pleurotus that have not been tested before: Pleurotus ostreatus and Pleurotus eryngii, growing on a sandy loam soil. These fungi presented different intra- and extracellular enzymatic systems (chytochrome P450 (CYP450), laccase, Mn peroxidase (MnP)) capable of aerobically degrading TCE to less harmful compounds. The potential toxicity of TCE to P. ostreatus and P. eryngii was firstly tested in a TCE-spiked liquid broth (70 mg L−1 and 140 mg L−1) for 14 days. Then, both fungi were assessed for their ability to degrade the pollutant in sandy loam soil spiked with 140 mg kg−1 of TCE. P. ostreatus and P. eryngii improved the natural dissipation of TCE from soil by 44%. Extracellular enzymes were poorly expressed, but mainly in the presence of the contaminant, in accordance with the hypothesis of the involvement of CYP450.

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Decolorization of Coal Humic Acid by Extracellular Enzymes Produced by White-Rot Fungi

Coal Preparation ◽

10.1080/07349340500444463 ◽

2005 ◽

Vol 25 (4) ◽

pp. 211-220 ◽

Cited By ~ 11

Author(s):

Y. Kabe ◽

T. Osawa ◽

A. Ishihara ◽

T. Kabe

Keyword(s):

Humic Acid ◽

Extracellular Enzymes ◽

White Rot Fungi ◽

White Rot

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Coculture of white rot fungi enhance laccase activity and its dye decolorization capacity

Research Society and Development ◽

10.33448/rsd-v9i11.10643 ◽

2020 ◽

Vol 9 (11) ◽

pp. e88191110643

Author(s):

Katielle Vieira Avelino ◽

Marisangela Isabel Wietzikoski Halabura ◽

Renan Alberto Marim ◽

Nelma Lopes Araújo ◽

Maria Graciela Iecher Faria Nunes ◽

...

Keyword(s):

Biomass Production ◽

Extracellular Enzymes ◽

Laccase Activity ◽

Dye Degradation ◽

White Rot Fungi ◽

White Rot ◽

Mycelial Biomass ◽

Pycnoporus Sanguineus ◽

Biochemical Alterations

Fungal cocultures can promote complex interactions that result in physiological and biochemical alterations that favor the synergic and more efficient action of extracellular enzymes such as laccase. Thus, coculture can be used as a strategy to increase enzymatic activity, dye degradation, and bioremediation of textile effluents. This study aimed to evaluate the coculture effect of Lentinus crinitus, Pleurotus ostreatus, Pycnoporus sanguineus, and Trametes polyzona on laccase activity, mycelial biomass production, and in vitro decolorization of azo, anthraquinone, and triphenylmethane dyes. The species were cultivated in liquid medium in monoculture and coculture in paired combinations for 15 days to determine the laccase activity and produced mycelial biomass. The enzymatic extracts of fungal cultivations were used in decolorization tests of reactive blue 220 (RB220), malachite green (MG), and remazol brilliant blue R (RBBR). Pleurotus-Trametes, Lentinus-Pleurotus, and Lentinus-Trametes cocultures increase laccase activity compared to respective monocultures. Lentinus-Pycnoporus, Lentinus-Trametes, Lentinus-Pleurotus, and Pleurotus-Trametes cocultures stimulate mycelial biomass production in relation to their respective monocultures. The enzymatic extracts of monocultures and cocultures promoted the decolorization of all dyes. RB220 dye presented fast decolorization. In 24 h, all extracts reached maximum decolorization and the greatest color reduction percentage was 90% for Pleurotus-Trametes coculture extract. Pleurotus-Trametes extract also increased the decolorization of MG and RBBR dyes when compared to their respective monocultures in 48 h and 72 h, respectively. However, RBBR dye presented the greatest resistance to decolorization.

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