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Applied and Environmental Microbiology Feb 2024White-rot fungi, such as , are the most efficient degraders of lignin, a major component of plant biomass. Enzymes produced by these fungi, such as lignin peroxidases...
White-rot fungi, such as , are the most efficient degraders of lignin, a major component of plant biomass. Enzymes produced by these fungi, such as lignin peroxidases and manganese peroxidases, break down lignin polymers into various aromatic compounds based on guaiacyl, syringyl, and hydroxyphenyl units. These intermediates are further degraded, and the aromatic ring is cleaved by 1,2,4-trihydroxybenzene dioxygenases. This study aimed to characterize homogentisate dioxygenase (HGD)-like proteins from that are strongly induced by the G-unit fragment of vanillin. We overexpressed two homologous recombinant HGDs, PcHGD1 and PcHGD2, in . Both PcHGD1 and PcHGD2 catalyzed the ring cleavage in methoxyhydroquinone (MHQ) and dimethoxyhydroquinone (DMHQ). The two enzymes had the highest catalytic efficiency (/) for MHQ, and therefore, we named PcHGD1 and PcHGD2 as MHQ dioxygenases 1 and 2 (PcMHQD1 and PcMHQD2), respectively, from . This is the first study to identify and characterize MHQ and DMHQ dioxygenase activities in members of the HGD superfamily. These findings highlight the unique and broad substrate spectra of PcHGDs, rendering them attractive candidates for biotechnological applications.IMPORTANCEThis study aimed to elucidate the properties of enzymes responsible for degrading lignin, a dominant natural polymer in terrestrial lignocellulosic biomass. We focused on two homogentisate dioxygenase (HGD) homologs from the white-rot fungus, , and investigated their roles in the degradation of lignin-derived aromatic compounds. In the genome database, PcMHQD1 and PcMHQD2 were annotated as HGDs that could cleave the aromatic rings of methoxyhydroquinone (MHQ) and dimethoxyhydroquinone (DMHQ) with a preference for MHQ. These findings suggest that MHQD1 and/or MHQD2 play important roles in the degradation of lignin-derived aromatic compounds by . The preference of PcMHQDs for MHQ and DMHQ not only highlights their potential for biotechnological applications but also underscores their critical role in understanding lignin degradation by a representative of white-rot fungus, .
Topics: Lignin; Dioxygenases; Phanerochaete; Homogentisate 1,2-Dioxygenase; Proteins; Peroxidases
PubMed: 38259078
DOI: 10.1128/aem.01753-23 -
Mycobiology Dec 2006One of the most economically viable processes for the bioconversion of many lignocellulosic waste is represented by white rot fungi. Phanerochaete chrysosporium is one... (Review)
Review
One of the most economically viable processes for the bioconversion of many lignocellulosic waste is represented by white rot fungi. Phanerochaete chrysosporium is one of the important commercially cultivated fungi which exhibit varying abilities to utilize different lignocellulosic as growth substrate. Examination of the lignocellulolytic enzyme profiles of the two organisms Phanerochaete chrysosporium and Rhizopus stolonifer show this diversity to be reflected in qualitative variation in the major enzymatic determinants (ie cellulase, xylanase, ligninase and etc) required for substrate bioconversion. For example P. chrysosporium which is cultivated on highly lignified substrates such as wood (or) sawdust, produces two extracellular enzymes which have associated with lignin deploymerization. (Mn peroxidase and lignin peroxidase). Conversely Rhizopus stolonifer which prefers high cellulose and low lignin containg substrates produce a family of cellulolytic enzymes including at least cellobiohydrolases and β-glucosidases, but very low level of recognized lignin degrading enzymes.
PubMed: 24039492
DOI: 10.4489/MYCO.2006.34.4.159 -
International Journal of Biological... Sep 2009The development of alternative energy technology is critically important because of the rising prices of crude oil, security issues regarding the oil supply, and... (Review)
Review
The development of alternative energy technology is critically important because of the rising prices of crude oil, security issues regarding the oil supply, and environmental issues such as global warming and air pollution. Bioconversion of biomass has significant advantages over other alternative energy strategies because biomass is the most abundant and also the most renewable biomaterial on our planet. Bioconversion of lignocellulosic residues is initiated primarily by microorganisms such as fungi and bacteria which are capable of degrading lignocellulolytic materials. Fungi such as Trichoderma reesei and Aspergillus niger produce large amounts of extracellular cellulolytic enzymes, whereas bacterial and a few anaerobic fungal strains mostly produce cellulolytic enzymes in a complex called cellulosome, which is associated with the cell wall. In filamentous fungi, cellulolytic enzymes including endoglucanases, cellobiohydrolases (exoglucanases) and beta-glucosidases work efficiently on cellulolytic residues in a synergistic manner. In addition to cellulolytic/hemicellulolytic activities, higher fungi such as basidiomycetes (e.g. Phanerochaete chrysosporium) have unique oxidative systems which together with ligninolytic enzymes are responsible for lignocellulose degradation. This review gives an overview of different fungal lignocellulolytic enzymatic systems including extracellular and cellulosome-associated in aerobic and anaerobic fungi, respectively. In addition, oxidative lignocellulose-degradation mechanisms of higher fungi are discussed. Moreover, this paper reviews the current status of the technology for bioconversion of biomass by fungi, with focus on mutagenesis, co-culturing and heterologous gene expression attempts to improve fungal lignocellulolytic activities to create robust fungal strains.
Topics: Biomass; Cellulase; Cellulosomes; Fungal Proteins; Fungi; Lignin
PubMed: 19774110
DOI: 10.7150/ijbs.5.578 -
Medical Mycology Journal 2019Lophophyton gallinae (Microsporum gallinae) is a zoophilic fungus that causes ringworm in chickens and related species, and occasionally in humans. There are 45 human... (Review)
Review
Lophophyton gallinae (Microsporum gallinae) is a zoophilic fungus that causes ringworm in chickens and related species, and occasionally in humans. There are 45 human cases worldwide including a Japanese case from Okinawa in 2009. After the finding of the human L. gallinae case, 793 chickens in Japan, including 293 from the mainland and 500 from the Nansei Island areas, were investigated to determine the prevalence of dermatophytes and their related fungal species. The survey was carried out from December 2008 to March 2013. Various dermatophytes and related fungal species were isolated from the studied chickens, with a prevalence of 24.6%. In total, 224 dermatophytes and related species were isolated in the survey. The most commonly isolated species included, in descending order of frequency, Arthroderma multifidum, Aphanoascus terreus, and Chrysosporium spp. Ar. multifidum and Ap. terreus have no record of pathogenicity, and the present isolates of Chrysosporium spp. were not matched to pathogenic Chrysosporium spp. based on the ITS rDNA sequences. Interestingly, an L. gallinae isolate was detected in a male 10-month-old shamo (fighting cock) from the main island. Furthermore, one strain of Arthroderma simii was also isolated as the second record in Japan following that from an imported chimpanzee. Although L. gallinae and Ar. simii are likely to be endemic in our country, the transmission of dermatophytosis from chickens to humans is unlikely to occur because of the reduced chances for citizens to come in contact with chickens due to various factors.
Topics: Animals; Arthrodermataceae; Chickens; Chrysosporium; DNA, Fungal; DNA, Ribosomal; Dermatomycoses; Humans; Japan; Microsporum; Pan troglodytes; Sequence Analysis, DNA; Zoonoses
PubMed: 31155571
DOI: 10.3314/mmj.19.002 -
Frontiers in Bioengineering and... 2020The ability of white-rot fungi to degrade polysaccharides in lignified plant cell walls makes them a suitable reservoir for CAZyme prospects. However, to date, CAZymes...
The ability of white-rot fungi to degrade polysaccharides in lignified plant cell walls makes them a suitable reservoir for CAZyme prospects. However, to date, CAZymes from these species are barely studied, which limits their use in the set of choices for biomass conversion in modern biorefineries. The current work joined secretome studies of two representative white-rot fungi, and , with expression analysis of cellobiohydrolase (CBH) genes, and use of the secretomes to evaluate enzymatic conversion of simple and complex sugarcane-derived substrates. Avicel was used to induce secretion of high levels of CBHs in the extracellular medium. A total of 56 and 58 proteins were identified in cultures of and , respectively, with 78-86% of these proteins corresponding to plant cell wall degrading enzymes (cellulolytic, hemicellulolytic, pectinolytic, esterase, and auxiliary activity). CBHI predominated among the plant cell wall degrading enzymes, corresponding to 47 and 34% of the detected proteins in and , respectively, which confirms that Avicel is an efficient CBH inducer in white-rot fungi. The induction by Avicel of genes encoding CBHs () was supported by high expression levels of and C in and , respectively. Both white-rot fungi secretomes enabled hydrolysis experiments at 10 FPU/g substrate, despite the varied proportions of CBHs and other enzymes present in each case. When low recalcitrance sugarcane pith was used as a substrate, and secretomes performed similarly to Cellic CTec2. However, the white-rot fungi secretomes were less efficient than Cellic CTec2 during hydrolysis of more recalcitrant substrates, such as acid or alkaline sulfite-pretreated sugarcane bagasse, likely because Cellic CTec2 contains an excess of CBHs compared with the white-rot fungi secretomes. General comparison of the white-rot fungi secretomes highlighted enzymes for providing high glucan conversions, even at lower proportion of CBHs, probably because the other enzymes present in this secretome and CBHs lacking carbohydrate-binding modules compensate for problems associated with unproductive binding to lignin.
PubMed: 32766234
DOI: 10.3389/fbioe.2020.00826 -
Revista Argentina de Microbiologia 2018The degree of antagonism exercised by fungi on geohelminth development varies according to the morphological alterations caused by different fungal species. Saprophytic...
The degree of antagonism exercised by fungi on geohelminth development varies according to the morphological alterations caused by different fungal species. Saprophytic fungi may exert ovicidal or ovistatic effects. The aim of this study was to apply scanning electron microscopy (SEM) to observe the action of two soil saprophytic species of Chrysosporium (C. indicum and C. keratinophylum) on Toxocara canis eggs. The fungal strains to be tested were incubated for 28 days at 28°C in 2% water agar with a suspension of unembryonated T. canis eggs. A suspension of T. canis eggs in 2% water agar was used as control group. The assay was done in triplicate for each fungus and the control group. SEM observations were performed on the 4th, 7th, 14th, 21st, and 28th day after inoculation. The effect of the fungi on eggs was evaluated in accordance with the alterations observed on the surface and the changes in the normal characteristics of the eggs. Hyphae around the eggs, appresoria penetrating the shell and changes in the typical egg membrane were observed in this assay. Type 3 effect (alterations that occur both in the embryo and the shell, and hyphal penetration of the eggs) was the prevalent effect. SEM allowed us to observe clearly the morphological alterations in T. canis eggs due to the effect of C. indicum and C. keratinophylum. Both saprophytic species of Chrysosporium alter the egg structure and alterations increase as exposure increases.
Topics: Animals; Chrysosporium; Fungi; Ovum; Soil; Soil Microbiology; Toxocara canis
PubMed: 29221930
DOI: 10.1016/j.ram.2017.08.001 -
Microbial Cell Factories Jan 2021Cellobiose dehydrogenase from Phanerochaete chrysosporium (PcCDH) is a key enzyme in lignocellulose depolymerization, biosensors and biofuel cells. For these...
BACKGROUND
Cellobiose dehydrogenase from Phanerochaete chrysosporium (PcCDH) is a key enzyme in lignocellulose depolymerization, biosensors and biofuel cells. For these applications, it should retain important molecular and catalytic properties when recombinantly expressed. While homologous expression is time-consuming and the prokaryote Escherichia coli is not suitable for expression of the two-domain flavocytochrome, the yeast Pichia pastoris is hyperglycosylating the enzyme. Fungal expression hosts like Aspergillus niger and Trichoderma reesei were successfully used to express CDH from the ascomycete Corynascus thermophilus. This study describes the expression of basidiomycetes PcCDH in T. reesei (PcCDH) and the detailed comparison of its molecular, catalytic and electrochemical properties in comparison with PcCDH expressed by P. chrysosporium and P. pastoris (PcCDH).
RESULTS
PcCDH was recombinantly produced with a yield of 600 U L after 4 days, which is fast compared to the secretion of the enzyme by P. chrysosporium. PcCDH and PcCDH were purified to homogeneity by two chromatographic steps. Both enzymes were comparatively characterized in terms of molecular and catalytic properties. The pH optima for electron acceptors are identical for PcCDH and PcCDH. The determined FAD cofactor occupancy of 70% for PcCDH is higher than for other recombinantly produced CDHs and its catalytic constants are in good accordance with those of PcCDH. Mass spectrometry showed high mannose-type N-glycans on PcCDH, but only single N-acetyl-D-glucosamine additions at the six potential N-glycosylation sites of PcCDH, which indicates the presence of an endo-N-acetyl-β-D-glucosaminidase in the supernatant.
CONCLUSIONS
Heterologous production of PcCDH is faster and the yield higher than secretion by P. chrysosporium. It also does not need a cellulose-based medium that impedes efficient production and purification of CDH by binding to the polysaccharide. The obtained high uniformity of PcCDH glycoforms will be very useful to investigate electron transfer characteristics in biosensors and biofuel cells, which are depending on the spatial restrictions inflicted by high-mannose N-glycan trees. The determined catalytic and electrochemical properties of PcCDH are very similar to those of PcCDH and the FAD cofactor occupancy is good, which advocates T. reesei as expression host for engineered PcCDH for biosensors and biofuel cells.
Topics: Carbohydrate Dehydrogenases; Cellobiose; Glycosylation; Hypocreales; Phanerochaete; Recombinant Proteins; Transformation, Genetic
PubMed: 33407462
DOI: 10.1186/s12934-020-01492-0 -
International Journal of Environmental... Jun 2020Eutrophication has become a severe environmental problem. This study evaluated the algicidal efficiency and genotoxic effects of co-cultured with for 48 h under the...
Eutrophication has become a severe environmental problem. This study evaluated the algicidal efficiency and genotoxic effects of co-cultured with for 48 h under the optimum conditions of 250 mg/L of at 25 °C with dissolved oxygen content of 7.0 mg/L. The results showed that the activity of algal dehydrogenase, superoxide dismutase, and peroxidase were all decreased and the malondialdehyde content increased after co-culturing. Fourier transform infrared spectroscopy and scanning electron microscopy observations showed that the functional group and structure of algal cells were significantly changed. Compared with those of control tadpoles, blood cells of tadpoles had increased micronucleus frequency (from 1.05 ± 0.09 to 1.99 ± 0.05) and abnormal nuclei (from 2.45 ± 0.06 to 5.83 ± 0.07). The tail length of co-cultured with increased from 1.12 ± 0.21 to 21.68 ± 0.34, and the comet length increased from 6.45 ± 0.09 to 36.45 ± 0.67 within 48 h. Micronucleus assay and Comet assay results demonstrated that might effectively remove algae and reduce genotoxic effects and may be safe for aquatic ecosystems.
Topics: DNA Damage; Ecosystem; Eutrophication; Microcystis; Phanerochaete
PubMed: 32517048
DOI: 10.3390/ijerph17114029 -
Frontiers in Cellular and Infection... 2022Accumulating evidence indicates that gut microbiota dysbiosis contributes to colorectal cancer and adenoma. However, a few studies revealed the altered gut mycobiota...
Accumulating evidence indicates that gut microbiota dysbiosis contributes to colorectal cancer and adenoma. However, a few studies revealed the altered gut mycobiota architecture in colorectal cancer. The present study characterized the gut mycobiota profiles in adenoma and colorectal cancer patients by metagenomic sequencing. increased, while and significantly decreased in adenoma. , , and were the top 3 fungi that were significantly enriched in colorectal cancer, while , , and were dominant in the healthy controls. Thirteen fungi, ranked as critical biomarkers in diagnosing colorectal cancer, showed positive associations among all samples. and showed the most significant association within CRC. The values of area under the receiver-operating characteristics curve (AUROC) of selected 13 mycobiota were 0.926 in the training model and 0.757 in the 10-fold validation model. Our study provided a reliable investigation of the alterations of gut mycobiota in the development of colorectal cancer and established a convincing diagnostic model for colorectal cancer, which might improve the treatment strategy for colorectal cancer in the future.
Topics: Adenoma; Colorectal Neoplasms; Dysbiosis; Feces; Gastrointestinal Microbiome; Humans
PubMed: 35281451
DOI: 10.3389/fcimb.2022.839435 -
PLoS Pathogens Oct 2014
Review
Topics: Animals; Chrysosporium; Classification; Humans; Incidence; Infections; Reptiles; Virulence
PubMed: 25329049
DOI: 10.1371/journal.ppat.1004367