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Ceriporiopsis subvermispora (C. subvermispora) is a selective degrader of lignin in the woody biomass. Glutathione S-transferases (GSTs) are multifunctional enzymes that play important roles in cellular detoxification and metabolism. The crystal structures of a GST of C. subvermispora , CsGST83044, in GSH-free and -bound forms were solved at 1.95 and 2.19 Å resolution, respectively. The structure of the GSH-bound form revealed that CsGST83044 can be categorized as an atypical-type of GST. In the GSH-bound form of CsGST83044, Asn22, Asn24, and Tyr46 are located closest to the sulfur atom and form hydrogen bonds with the thiol group. The functional mutagenesis indicated that they are critical for the enzymatic activities of CsGST83044. The critical residues of an atypical-type GST belonging to the GSTFuA class were revealed for the first time. A previous study indicated that CsGST83044 and another GST, CsGST63524, differ in substrate preference; CsGST83044 prefers smaller substrates than CsGST63524 for its esterase activity. The GSH-bound pocket of CsGST83044 turns out to be small, which may explain the preference for smaller substrates. Protein engineering of GSTs of C. subvermispora in the light of the obtained insight may pave a path in the future for utilization of the woody biomass. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Unsterilized corn stover, miscanthus, hardwood, and softwood were fungal pretreated. • Fungal pretreatment increased the enzymatic digestibility of non-sterile feedstocks. • Effects of fungal pretreatment on structure and composition depended on feedstock. • Sequential unsterilized fungal pretreatment was ineffective after second generation. • Fungal pretreatment was more effective for woods than herbaceous feedstocks. Abstract Fungal pretreatment with the white rot fungus Ceriporiopsis subvermispora was performed under non-sterile conditions for four different feedstocks, corn stover, miscanthus, softwood, and hardwood, using a sequential inoculation process that employed fungal-colonized feedstock as inoculum. Fungal pretreatment improved the enzymatic digestibility of unsterilized hardwood, softwood, and miscanthus after the first generation of the sequential process, increasing the glucose yield by 2-, 3- and 4.5- fold, and the xylose yield by 9-, 7- and 10- fold, respectively. However, the fungal pretreatment of unsterilized feedstocks was unsuccessful for corn stover throughout the sequential process and for all feedstocks for the second and third generation. Modifications in feedstock structure and composition were analyzed using microscopy, spectroscopy, and thermogravimetric analysis, and showed that the effects of fungal pretreatment with C. subvermispora were feedstock-dependent. A significant fungal colonization was observed in all the fungal pretreated feedstocks, but an extensive cell wall degradation was only detected in miscanthus and hardwood. Lignin-to-cellulose ratio decreased in all successful fungal pretreated feedstocks, but the lignin units (syringyl, guaiacyl, or p-hydroxyphenyl units) that were preferentially degraded varied with each feedstock. Interestingly, C. subvermispora was able to degrade terpenes from the pine resin during the fungal pretreatment of pine wood (softwood). [ABSTRACT FROM AUTHOR]

• C. subvermispora modification mechanism of corn stover was studied. • Tendency of lignocellulose degradation changed during C. subvermispora modification. • C. subvermispora modification for 15 d increased methane yield of corn stover by 15.2%. • Selective delignification was highly correlated to methane yield of corn stover. Ceriporiopsis subvermispora was used to modify corn stover for improving the biodegradability and biomethane yield. Corn stover was incubated with C. subvermispora for 5–90 days then anaerobically digested. It was found that the corn stover modified for 15 days achieved the highest biomethane yield of 235 mL·g−1 VS, which was an increase of 15.2% over that of the non-modified one. The mechanism analyses indicated that the improvement resulted from the combined roles of degradation selectivity, destruction of lignocellulosic structures, and linkages. The analyses showed that C. subvermispora has a high relative selectivity of lignin degradation. The structure of the lignin and the linkages among lignin and hemicellulose and cellulose were broken obviously by acetyl group removal, and the enzymatic hydrolysis of cellulose was increased by 35.61%. The finding indicated that C. subvermispora modification is one of the effective methods for enhancing biomethane yield of corn stover. [ABSTRACT FROM AUTHOR]

Glutathione S-transferases (GSTs) of wood-degrading fungi play essential roles in cellular detoxification processes and endogenous metabolism. Fungal GSTs of GSTFuA class are suggested to be involved in lignin degradation. Ceriporiopsis subvermispora is one of the important model fungi of the selective lignin degraders, we found it interesting to study its GSTs. Here, we characterized the activities of two GSTs of the GSTFuA class of C . subvermispora (CsGST63524 and CsGST83044). A high-yield expression systems involving Escherichia coli was developed for each of these enzymes. Both enzymes were found to exhibit GSH-conjugation activity toward 1-chloro-2,4-dinitrobenzene, and GSH-peroxidase activity toward cumene hydroperoxide. Both enzymes showed high GSH-conjugation activity under basic conditions (pH 8.0 to 9.0), and the optimum temperature for their activity was 40 °C. In addition, three fluorescent compounds were used i . e ., methylumbelliferyl acetovanillone was used to monitor etherase activity, and 5-chloromethylfluorescein diacetate and 4-methylumbelliferyl acetate to monitor esterase activity. CsGST83044 exhibited both etherase and esterase activities, while CsGST63524 displayed only esterase activity, which was much higher than that of CsGST83044. These findings imply the functional diversity of the GSTFuA class GSTs of C . subvermispora , suggesting that each protein plays distinctive roles in both the fungal detoxification system and wood compound metabolism. [ABSTRACT FROM AUTHOR]

The functions and properties of fungal sheath, an extracellular polysaccharide produced by many white-rot fungi, have been studied. However, the strong adherence of the sheath to fungal hyphae had been a major impediment in preparing intracellular proteins from the fungi and analyzing their cellular responses. To overcome this issue, we developed a rapid and easy method to remove the polysaccharide sheath using a selective lignin degrader, Ceriporiopsis subvermispora , which produces large sheath amounts in the presence of a lignin-derived aromatic compound. Using this approach, we achieved thorough removal of sheath and cell disruption using beads and a solution with a high protein-solubilizing power, which enabled the efficient extraction of intracellular proteins from C . subvermispora surrounded by sheath. In addition, for proteomic analysis, we investigated whether these extracted proteins were compatible with two-dimensional electrophoresis. By efficiently concentrating on protein solubilization in the first dimension and using a stacking gel in the second dimension, we successfully obtained a high-resolution proteome map of C . subvermispora . We also used the same proteins for fluorescence two-dimensional difference gel electrophoresis to obtain the quantitative protein expression profiles. These steps demonstrated that two-dimensional electrophoresis-based proteomics can be used to clarify the composition of intracellular proteins from sheath-producing white-rot fungi. [ABSTRACT FROM AUTHOR]

Oxygen transfer in submerged cultures of basidiomycetes is a key factor for efficient fungal growth. However, conventional stirred tank and airlift reactors are not utterly suitable for basidiomycetes culturing because they promote high shear stress to the mycelial hyphae and favor rapid agglomeration of mycelial pellets, compromising the diffusion of oxygen to the inner side of mycelium. We describe an original reactor design that overcome some of the limitations of conventional bioreactors used in submerged cultures of basidiomycetes. The strategy was to use a mechanism that permits simultaneous axis rotation and air injection, being the agitation promoted by an L-shaped tube. Adherence of mycelium and shear stress is avoided once only rounded surfaces exist inside the bioreactor. Ceriporiopsis subvermispora was selected as a model basidiomycete. The most productive system employed sucrose/corn steep liquor as the culture medium and pulsed addition of sucrose during the culturing. This approach provided efficient mycelial growth (maximum of 14.1 g·L –1 ), and avoided pH increase and pellet agglomeration throughout the fungal cultivation for 7 days, resulting in a biomass productivity of 1.72 g·L –1 ·day –1 . Microscopic evaluation of chlamydospores accumulation in the grown mycelium confirmed that minimal fungal stress occurred in the cultures performed in the new designed bioreactor, contrasting with cultures carried out in conventional stirred tank bioreactors. [ABSTRACT FROM AUTHOR]

Miscanthus was pretreated with the fungus Ceriporiopsis subvermispora under non-sterile conditions, using sterile miscanthus that had been previously colonized with the fungus as the inoculum. Inoculum ratios equal to or greater than 30% yielded a successful pretreatment, enhancing the enzymatic digestibility of miscanthus by 3- to 4-fold over that of raw miscanthus, which was comparable with the fungal pretreatment under sterile conditions. This enhanced digestibility was linearly correlated with lignin degradation. Although cellulose loss of up to 13% was observed for the successful non-sterile pretreatments, the final glucose yield was 3–4 times higher than that of raw miscanthus and comparable to that of the sterile pretreated miscanthus. A time course study showed that maximum glucose yield can be achieved with a pretreatment time of 21 days. [ABSTRACT FROM AUTHOR]

Solid-state anaerobic digestion of Miscanthus sinensis harvested in fall and spring was compared under different total solids contents and feedstock-to-inoculum ratios. The highest specific methane yields reached 170–175 L CH 4 /kg volatile solids for both harvest seasons. Miscanthus harvested in fall generated a 6% higher methane yield in average than miscanthus harvested in spring. Fungal pretreatment with Ceriporiopsis subvermispora decreased the lignin content of miscanthus harvested in spring by 25.7%, but there was no significant delignification observed for miscanthus harvested in fall. Fungal pretreatment of miscanthus harvested in spring increased the specific methane yield by 25%, but fungal pretreatment caused a slight methane yield reduction for miscanthus harvested in fall. Methane yields for miscanthus were comparable with those from other energy crops. [ABSTRACT FROM AUTHOR]

Abstract: Aqueous extracts from wood biotreated with the white-rot fungus Ceriporiopsis subvermispora were evaluated for their Fe3+- and Cu2+-reducing activities and their anti- or prooxidant properties in Fenton-like reactions to decolorize the recalcitrant dye Azure B. The decolorization of Azure B was strongly inhibited in the presence of 10% (v/v) wood extracts. Only 0.1% (v/v)-diluted extracts provided some enhancement of the Azure B decolorization. The iron-containing reactions decolorized more Azure B and consumed substantially more H2O2 than the reactions containing copper. This study demonstrates that water-soluble wood phenols exert anti- or prooxidant effects that depend on their concentration in the reactions and on the type of cation, Fe3+ or Cu2+, used to convert H2O2 to OH radicals. [Copyright &y& Elsevier]

Abstract: Pinus taeda wood chips were treated with the biopulping fungus Ceriporiopsis subvermispora in calcium- or oxalic acid-amended cultures. The secretion of hydrolytic and oxidative enzymes was inhibited only in the cultures having the highest concentration of calcium (1400 mg kg−1 wood). Calcium decreased the availability of free oxalic acid, inhibited fungal growth, and reduced lignin mineralization and transformations. Oxalic acid amendment in the cultures was found not to affect the lignin mineralization and transformations; however, it did inhibit the depolymerization reactions detectable in the residual lignin that was retained in the biotreated wood. C. subvermispora presented catabolic activity for oxalic acid in the cultures amended with 1660 mg acid kg−1 wood, whereas oxalic acid was synthesized when it was amended at low amounts or initially absent in the cultures. These data suggest one ideal ratio of oxalic acid in C. subvermispora cultures and indicate that its exogenous addition does not necessarily accompany the further degradation of lignin. [Copyright &y& Elsevier]

Abstract: Storage of lignocellulosic biomass is critical for a year-round supply of feedstock for a biorefinery. Compared with dry storage, wet storage is a promising alternative technology, providing several advantages including reduced dry matter loss and fire risk and improved feedstock digestibility after storage. This study investigated the concurrent pretreatment and wet-storage of corn stover with the assistance of NaOH or a lignin-degrading fungus, Ceriporiopsis subvermispora, during a 90-d period. Compared with ensilage, adding NaOH or inoculation with C. subvermispora significantly enhanced the enzymatic degradability of corn stover by 2–3-fold after 90-d wet storage. Lignin and xylan removal during NaOH pretreatment and wet-storage were influenced by NaOH loading and moisture. NaOH pretreatment retarded the production of organic acids during storage and the acetate release correlated with lignin and xylan removal. Further study is needed to reduce cellulose degradation during the late stage of fungal treatment. [Copyright &y& Elsevier]

Abstract: European black pine (Pinus nigra Arn.) chips were treated with the white-rot fungus Ceriporiopsis subvermispora for periods ranging from 20 to 100 days. The effects of pretreatment on the chemical composition of wood and kraft pulping were investigated. The results showed that fungal pretreatment reduced the lignin and extractive content of wood chips. Also, weight losses occurred. Kappa number, viscosity, and reject ratio of biokraft pulps decreased. Biokraft pulps gave better response to beating, which led to significant energy saving during refining. The tear index, burst index, and tensile index of biokraft pulps were found to be lower than those of kraft pulps. However, the tensile index and burst index of 20-day biotreated and unbeaten pulp was higher than those of kraft pulp. Also, the tear index of 20-day biotreated and beaten pulp was higher than that of kraft pulp. The brightness of biokraft pulps decreased irregularly with increasing incubation time. [Copyright &y& Elsevier]

Abstract: This work evaluates linoleic acid peroxidation reactions initiated by Fe3+-reducing compounds recovered from Eucalyptus grandis, biotreated with the biopulping fungus Ceriporiopsis subvermispora. The aqueous extracts from biotreated wood had the ability to reduce Fe3+ ions from freshly prepared solutions. The compounds responsible for the Fe3+-reducing activity corresponded to UV-absorbing substances with apparent molar masses from 3kDa to 5kDa. Linoleic acid peroxidation reactions conducted in the presence of Fe3+ ions and the Fe3+-reducing compounds showed that the rate of O2 consumption during peroxidation was proportional to the Fe3+-reducing activity present in each extract obtained from biotreated wood. This peroxidation reaction was coupled with in-vitro treatment of ball-milled E. grandis wood. Ultraviolet data showed that the reaction system released lignin fragments from the milled wood. Size exclusion chromatography data indicated that the solubilized material contained a minor fraction representing high-molar-mass molecules excluded by the column and a main low-molar-mass peak. Overall evaluation of the data suggested that the Fe3+-reducing compounds formed during wood biodegradation by C. subvermispora can mediate lignin degradation through linoleic acid peroxidation. [ABSTRACT FROM AUTHOR]

Abstract: Pinus taeda wood chips were treated with the biopulping fungus Ceriporiopsis subvermispora in soybean-oil-amended cultures. The secretion of oxalic acid and the accumulation of thiobarbituric acid reactive substances were significantly increased in soybean-oil-amended cultures. By contrast, the secretion of hydrolytic and oxidative enzymes was not altered in the cultures. Biotreated wood samples were characterized for weight and component losses as well as by in-situ thioacidolysis. Residual lignins were also extracted from biotreated wood using a mild-non-razing extraction procedure. The lignins were characterized by 31P nuclear magnetic resonance (31P-NMR) spectroscopy. Soybean oil amendment in the cultures was found to affect lignin degradation routes; however, it inhibited depolymerization reactions detectable in the residual lignin that was retained in the biotreated wood. As a consequence, chemithermomechanical pulping of the biotreated samples was not improved by soybean oil amendment in the cultures. [ABSTRACT FROM AUTHOR]

Abstract: The feasibility of concurrent wet storage and microbial pretreatment of corn stover with Ceriporiopsis subvermispora for ethanol production was investigated in this study. The effects of particle size (5–15mm), moisture content (45–85%), pretreatment time (18–35 d), and temperature (4–37°C) on lignin degradation and enzymatic hydrolysis yield were studied. The results showed that C. subvermispora selectively degraded lignin up to 31.59% with a limited cellulose loss of less than 6% during an 18-d pretreatment. When 5mm corn stover was pretreated at 28°C with 75% moisture content, overall glucose yields of 57.67%, 62.21%, and 66.61% were obtained with 18-, 28-, and 35-d microbial pretreated corn stover, respectively. For the above conditions, the highest overall ethanol yield of 57.80% was obtained with 35-d-pretreated corn stover. Enzymatic hydrolysis yield was highly related to the lignin removal during microbial pretreatment. [Copyright &y& Elsevier]

Abstract: Delignification of corn stover by the white rot fungus Ceriporiopsis subvermispora in solid-state cultivation was evaluated for improving subsequent enzymatic hydrolysis. The results showed that C. subvermispora selectively degraded lignin by as much as 39.2% while the cellulose loss was less than 5% during 42d of cultivation. However, hemicellulose loss of up to 27.0% was concomitant with the lignin degradation. Ligninolytic enzymes, MnP and laccase, were detected during degradation of corn stover by C. subvermispora. For major hydrolytic enzymes, xylanase was the only enzyme detected. The enzymatic hydrolysis yield of corn stover delignified by C. subvermispora was remarkably improved, reaching about 57–67% overall glucose yield after 18–42d of pretreatment, while the glucose yield of the untreated was only 22%. A higher overall glucose yield of about 72% was obtained when the enzymatic hydrolysis of the 18d treated corn stover was supplemented with an accessory xylanase/cellulase enzyme complex. [Copyright &y& Elsevier]

Abstract: Ceriporiopsis subvermispora is a white-rot fungus used in biopulping processes and seems to use the fatty acid peroxidation reactions initiated by manganese-peroxidase (MnP) to start lignin degradation. The present work shows that C. subvermispora was able to peroxidize unsaturated fatty acids during wood biotreatment under biopulping conditions. In vitro assays showed that the extent of linoleic acid peroxidation was positively correlated with the level of MnP recovered from the biotreated wood chips. Milled wood was treated in vitro by partially purified MnP and linoleic acid. UV spectroscopy and size exclusion chromatography (SEC) showed that soluble compounds similar to lignin were released from the milled wood. SEC data showed a broad elution profile compatible with low molar mass lignin fractions. MnP-treated milled wood was analyzed by thioacidolysis. The yield of thioacidolysis monomers recovered from guaiacyl and syringyl units decreased by 33% and 20% in MnP-treated milled wood, respectively. This has suggested that lignin depolymerization reactions have occurred during the MnP/linoleic acid treatment. [Copyright &y& Elsevier]

Abstract: The degradation of the components of Japanese beech and Japanese cedar wood was measured over time in cultures of the white-rot fungus Ceriporiopsis subvermispora. Although there was no initial degradation of cedar wood, after 12 weeks the mass loss of both cedar and beech wood was 15–20%. The mass losses of filter paper in beech wood-containing cultures and glucose cultures after 12 weeks were 87% and 70%, respectively. The ratio of lignin loss to mass loss of both beech and cedar wood cultures approached 2.0. Although the cellulose loss in cedar wood was very low throughout the 12-week incubation, C. subvermispora degraded the hemicellulose in Japanese cedar much more effectively than that in Japanese beech. These results confirm that C. subvermispora is a selective lignin degrader. During the 12-week incubation with Japanese beech wood, C. subvermispora continuously produced at least one of three phenol oxidases: laccase was produced initially, followed by Mn-independent peroxidase activity peaking at 6 weeks and Mn-dependent peroxidase activity peaking at 10 weeks. Lignin peroxidase and carboxymethylcellulase activities peaked after 3 weeks of incubation. Avicelase activity was present throughout the incubation period, although the activity was very low. The low-molecular-mass fraction of the extracellular medium, which catalyzes a redox reaction between O2 and electron donors to produce hydroxyl radical, may act synergistically with the enzymes to degrade wood cell walls. [Copyright &y& Elsevier]

Abstract: Culturing bamboo with the white-rot fungus Ceriporiopsis subvermispora improved its nutritive value for ruminants. The bamboo substrate was prepared by grinding madake bamboo (Phyllostachys bambusoides) culm into a fibrous powder, mixing it with rice bran at an air-dry weight ratio of 19:1, then sterilizing the mixture at 118°C for 40min. After inoculating wheat grain spawn of C. subvermispora, the bamboo substrate was cultured at 28°C for 10 and 15 weeks. For in vivo digestion, mixed bamboo substrate (MBS) cultured for 10 or 15 weeks was used. Three sheep were each assigned to a diet group in a 3×3 Latin square experiment and fed either a basal diet composed of alfalfa hay cubes, wheat bran and soybean meal (699:201:100, on dry basis), 303g/kg of a basal diet replaced with bamboo or MBS. Organic matter (OM), neutral detergent fiber excluding residual ash (NDFom), acid detergent fiber excluded residual ash (ADFom), and lignin(sa) content of the bamboo substrate before inoculation decreased (P<0.05) following culture with C. subvermispora. The OM, NDFom and lignin(sa) content of the bamboo substrate cultured with C. subvermispora for 10 weeks were higher (P<0.05) than that of bamboo substrate cultured for 15 weeks. However, there was no difference in ADFom content of bumboo substrate between 10 and 15 weeks. The in vitro OM digestibility (IVOMD), in vitro NDFom digestibility (IVNDFomD), and in vitro gas production during 48h of incubation (IVGP) increased (P<0.05) in the bamboo substrate following culturing with C. subvermispora. NDFom and lignin(sa) content of bamboo used in in vivo digestion were 905g/kg DM and 198g/kg DM, respectively. NDFom and lignin(sa) content of MBS were 703g/kg DM and 106g/kg DM, respectively. The IVGP and IVOMD of bamboo were 19ml/g OM and 0.133, respectively, while those of MBS increased to 150ml/g OM and 0.671. The coefficients of apparent OM, NDFom and ADFom digestibility of bamboo were 0.129, 0.127 and 0.149, respectively, while those of MBS increased (P<0.05) to 0.447, 0.495 and 0.527, respectively. We suggest that C. subvermispora is capable of improving the nutritive value of bamboo that can then be used as a ruminant feed. [Copyright &y& Elsevier]

Abstract: One mannanase and one of the three xylanases produced by Ceriporiopsis subvermispora grown on Pinus taeda wood chips were characterized. A combination of ion exchange chromatography and SDS-PAGE data revealed the existence of a high-molecular-weight mannanase of 150kDa that was active against galactoglucomannan and xylan. Its activity was optimal at pH 4.5. The K m value with galactoglucomannan as substrate was 0.50mgml−1. One xylanase with molecular mass of 79kDa was also purified and characterized. Its activity was optimal at 60°C and pH 8.0. Its K m value with birchwood xylan as substrate was 1.65mgml−1. Both the mannanase and the 79kDa xylanase displayed relatively high activity on carboxymethyl cellulose. The sensitivity of the xylanase and mannanase to various salts was evaluated. None of the tested salts inhibited the xylanase, but Mn+2, Fe+3, and Cu+2 were strong inhibitors for the mannanase. [Copyright &y& Elsevier]

Abstract: Ceriporiopsis subvermispora was utilized for the biodegradation of Eucalyptus grandis in the presence or absence of co-substrates (glucose and corn steep liquor) during 7, 14 and 28 days. The biodegraded chips were used to prepare enzymatic extracts that, after pre-treatment with activated charcoal, were enriched in activity of manganese peroxidases (MnPs) with anion-exchange chromatography followed by elution with NaCl. Samples of these extracts were then analyzed by denaturing electrophoresis in order to compare the profiles of proteins and MnPs. Depending on the biodegradation period and on the presence or absence of co-substrates in the culture, one or two major proteins (relative molecular weights of 46.8±0.6 and 51.6±1.0kDa) were identified. The presence of MnPs activity was further confirmed by native electrophoresis followed by phenol red staining. [Copyright &y& Elsevier]

Abstract: Ceriporiopsis subvermispora was used for biochemical pulping of agricultural residues and the results were compared with chemical pulping. Independent variables were screened by Plackett–Burman and optimized by full factorial experimental designs. Biological treatment of rice, wheat and barley straw samples resulted in decrease of the kappa number of these straws by 34%, 21% and 19%, respectively, as compared with controlled samples. The tensile strength and burst factor of hand sheets produced from rice straw were increased by 51% and 33% as compared with the control straws. The tensile strength and burst factor of hand sheets produced from wheat straws were improved by 67% and 36%, these variables for barely straws were 36.7% and 45%, respectively. Although the delignification of wheat and barley straws are not as efficient as chemical process, but the quality of papers produced by biochemical pulping of straws were excellent. [Copyright &y& Elsevier]

Abstract: Ceriporiopsis subvermispora is a promising white-rot fungus for biopulping. However, the underlying biochemistry involved in lignin removal and insignificant cellulose degradation by this species is not completely understood. This paper addresses this topic focusing on the involvement of ethanol-soluble extractives and wood transformation products in the biodegradation process. Cultures containing ethanol-extracted or in natura wood chips presented similar levels of extracellular enzymes and degradation of wood components. Fe3+-reducing compounds present in undecayed Pinus taeda were rapidly diminished by fungal degradation. Lignin-degradation products released during biodegradation restored part of the Fe3+-reducing activity. However, Fe3+ reduction was ineffective in presence of 0.5mM oxalate at pH 4.5. Fungal consumption of Fe3+-reducing compounds and secretion of oxalic acid minimized the significance of Fenton''s reaction in the initial stages of wood biotreatment. This would explain limited polysaccharide degradation by the fungus that also lacks a complete set of hydrolytic enzymes. Scientific relevance of the paper: Ceriporiopsis subvermispora is a white-rot fungus suitable for biopulping processes because it degrades lignin selectively and causes significant structural changes on the wood components during the earlier decay stages. However, the intricate mechanism to explain lignin transformation and insignificant cellulose degradation by this species remains poorly understood. Some recent evidences pointed out for lipid peroxidation reactions as an initiating process explaining lignin degradation. On the other hand, alkylitaconic acids produced by the fungus via transformations of fatty acids occurring in wood showed to prevent polysaccharide degradation in Fenton reactions. [Copyright &y& Elsevier]

Abstract: Eucalyptus grandis biodegradation by Ceriporiopsis subvermispora in solid-state cultures supplemented with corn steep liquor (CSL), glucose and Mn2+ was evaluated. Chemical composition of biotreated wood was determined to correlate the extent of wood transformation with the levels of extracellular agents produced during fungal growth. Manganese-dependent peroxidases and xylanases were detected under all culture conditions. The lowest and the highest MnP activities were observed in cultures supplemented with Mn2+ and CSL/glucose (178 and 1317IUkg−1 of dry wood, respectively). In all cultures, glucan and xylan losses were lower than 3% while lignin loss varied from 2.7% to 9%. Lignin loss was correlated with the cleavage of aryl-ether linkages detected with basis on derivatization followed by reductive cleavage (DFRC) analysis. The highest lignin loss and the lowest yield of DFRC monomers were observed in cultures supplemented with Mn2+ and CSL. This culture condition presented intermediate levels of MnP production. Oxalate production was not strongly affected by addition of culture supplements suggesting that oxalate was not a limiting agent during wood degradation by C. subvermispora. Conversely, the results suggest that a compromise between the levels of MnP and Mn2+ was necessary to promote intense degradation of lignin revealed by DFRC analysis and lignin mass balances. [Copyright &y& Elsevier]

Abstract: Aligned epoxy-matrix composites were made from hemp fibres defibrated with the fungi Phlebia radiata Cel 26 and Ceriporiopsis subvermispora previously used for biopulping of wood. The fibres produced by cultivation of P. radiata Cel 26 were more cellulose rich (78%, w/w) than water-retted hemp due to more degradation of pectin and lignin. The defibrated hemp fibres had higher fibre stiffness (88–94GPa) than the hemp yarn (60GPa), which the fibre twisting in hemp yarn might explain. Even though mild processing was applied, the obtained fibre strength (643MPa) was similar to the strength of traditionally produced hemp yarn (677MPa). The fibre strength and stiffness properties are derived from composite data using the rule of mixtures model. The fibre tensile strength increased linearly with cellulose content to 850MPa for pure cellulose. The fibre stiffness increased also versus the cellulose content and cellulose crystallinity and reached a value of 125GPa for pure crystalline cellulose. [Copyright &y& Elsevier]

The Calabrien pine (Pinus brutia) wood chips prior to kraft pulping were biologically pre-treated with selected white-rot fungi (Ceriporiopsis subvermispora ), which was recorded to be preferentially attacking the lignin component of the wood. The effects of this treatment on beating performance and physical strength of resultant papers were studied in detail. Bio-treated samples showed comparable and, in most cases, higher physico-mechanical properties than those obtained from untreated controls. Under the same beating conditions the bio-treated kraft pulp was noted to have the lower SR* indicating a lower degree of external fibrillation. The paper made from bio-treated kraft pulp has a higher density, tensile property, air permeability and swellability. Furthermore, remarkable energy savings up to 33 % were observed when beating bio-treated kraft pulp. This study contributes to a better understanding of the mechanisms taking place during bio-treatment and the modification processes of cell wall components. [ABSTRACT FROM AUTHOR]

Abstract: Pinus taeda wood chips were treated with the biopulping fungus, Ceriporiopsis subvermispora, under solid-state fermentation for periods varying from 7 to 90 days. Low molecular mass compounds and oxidative enzymes were extracted from biotreated wood samples. Manganese-dependent peroxidase was the main oxidative enzyme on all biodegradation periods. Aqueous extracts from biotreated wood presented decreasing pH values, oxalic acid being the major organic acid secreted by the fungus. Analysis of these extracts by gas chromatography coupled with mass spectrometry (GC/MS) revealed small amounts of fatty acids, several short-chain organic acids (C3–C6) and numerous sugar derivatives. 3-methoxy-4-hydroxy benzaldehyde, 3-methoxy-4-hydroxy benzoic acid, 3,4-dihydroxy benzoic acid and tricarboxy-benzene were also found in the wood extracts. A remarkable characteristic of the wood extracts was a strong Fe3+-reducing ability. High Fe3+-reducing activity and high catechol concentrations were detected in the wood extracts from the undecayed control. This reducing activity and catechol concentrations decreased during the first 7 days of biodegradation. However, from the seventh day of culturing, catechol derivatives coming from lignin degradation start to accumulate in the cultures and Fe3+-reduction activity increased again. The Fe3+-reduction activity observed in the wood extracts indicates that Fe2+ would be available in solution during the wood decay process. Considering that Fe2+ and H2O2 (produced by this fungus based on MnP-degradation of oxalate) were present in the wood extracts, at least some extent for degradation reactions based on Fenton-chemistry, similarly to the observed in brown-rot fungi, is supposed to occur during wood decay by C. subvermispora. [Copyright &y& Elsevier]

Abstract: Production of cellulases and hemicellulases by Ceriporiopsis subvermispora cultured on wood chips of Eucalyptus grandis and Pinus taeda was studied. Xylanase, endo-1,4 β-glucanase, mannanase, β-glucosidase and β-xylosidase were detected in enzymatic extracts obtained after 30 days of cultivation. P. taeda gave rise to higher enzyme production compared to E. grandis. Biochemical characteristics of cellulases and hemicellulases produced in both wood species were almost the same. The optimum pH for the enzymes was between 4.0 and 5.0 and the optimum temperature was 60°C. Thermal stability of the enzymes at pH 5.0 was appreciable up to 50°C. The profile of proteins contained in extracts recovered from both biotreated wood species showed a similar number of bands during SDS-PAGE electrophoresis. Five bands with molecular weight ranging from 50 to 85kDa and two bands with high molecular weight (100–200kDa) were observed. Activity staining for xylanases indicated two enzymes with molecular weight of 80 and 33kDa. [Copyright &y& Elsevier]

Abstract: NAD-dependent formate dehydrogenase (FDH, EC 1.2.1.2.) was purified 34-fold with 5.8% yield as an electrophoretically homogeneous protein from the white-rot fungus Ceriporiopsis subvermispora. The native enzyme has a molecular mass of 84kDa consisting of two identical subunits as a homodimer. The K m values for formate and NAD were found to be 2.5mM and 28μM, respectively, at the optimum pH 6.5. The enzyme activity was inhibited by NADH, ADP, and ATP. The kinetic analysis indicated that the enzyme reaction proceeded by the ordered Bi Bi mechanism. Oxalate was found to be catabolized by mediations of oxalate decarboxylase (ODC, EC 4.1.1.2) and FDH during the vegetative growth of C. subvermispora, while it was oxidized by oxalate oxidase (OXO, EC 1.2.3.4) at the later stage of the cultivation. A possible role of the two-oxalate decomposing systems with ODC and OXO was discussed in relation to carbon metabolism of lignin-degrading basidiomycetes. [Copyright &y& Elsevier]

Abstract: The potential of five white-rot fungi to convert Japanese red cedar (Cryptomeria japonica) into feed for ruminants was determined. Pleurotus ostreatus (ATCC 66376), Pholiota nameko (IFO 30373), Dichomitus squalens (CBS 432.34), Lentinula edodes (IFO 6654) and Ceriporiopsis subvermispora (ATCC 90467) were inoculated into chips of cedar sapwood. L. edodes was cultured at 25°C, and the other fungi at 28°C, for 4, 8, 12, or 20 weeks. The in vitro organic matter (OM) digestibility (IVOMD) in cedar wood cultured without fungus were between 0.047 and 0.068, while it was elevated to 0.446 by culturing with C. subvermispora and to 0.281 by culturing with L. edodes for 20 weeks. In contrast, the IVOMD were 0.200, or lower, in cedar wood cultured with P. ostreatus, P. nameko, or D. squalens. The in vitro gas production (IVGP) in cedar wood cultured with P. ostreatus, P. nameko, or D. squalens was 37ml/g OM, or lower, while that in cedar not inoculated with fungus was between 4 and 17ml/g OM. In contrast, the IVGP in cedar wood cultured with C. subvermispora for 20 weeks increased to 107ml/g OM, and that in cedar wood cultured with L. edodes increased to 58ml/g OM. Lignin degradability in cedar wood cultured with C. subvermispora and L. edodes for 20 weeks were 0.578 and 0.288, respectively. These changes in IVOMD and IVGP demonstrate that a selective white-rot fungus, C. subvermispora has the ability to convert cedar wood into feed for ruminants, although further increase is required before the cultured cedar wood would have widespread feed potential. [Copyright &y& Elsevier]

Ceriporiopsis subvermispora is a white-rot basidiomycete that degrades lignin selectively and often is used in biopulping. Development of appropriate experimental procedures for recovery and determination of enzymes produced by C. subvermispora during biopulping is necessary to evaluate the role of each enzyme in this process. In this work, enzymes produced during biopulping were extracted and determined by using a series of substrates. Manganese-dependent peroxidases (MnP) predominated over laccases, which were of minor significance. The lack of laccases was further confirmed by assaying several substrates such as syrindaldazine, o-dianisidine and ABTS. A basal oxidation of syringaldazine and phenol red in the absence of exogenous Mn2+ led to the assumption that the extracts contained some Mn-independent peroxidase or enough Mn2+ to initiate MnP catalyzed reactions. The presence of Mn2+ was evidenced since phenol red was not oxidized by a 16-h-dialysed extract. Addition of 111 μM of Mn2+ to the reaction medium restored the oxidative activity. Lignin peroxidase activity was not detected in the extracts based on the Azure B assay. Cellulase activities were very low while xylanases predominated. The xylanolytic complex was deficient in beta-xylosidase. Successive extractions were performed for a quantitative recovery of the enzymes adsorbed on wood chips. The first 4-h extraction recovered an average of 50% of the total enzymatic activities. [Copyright &y& Elsevier]

Ethanol was produced by simultaneous saccharification and fermentation (SSF) from beech wood chips after bioorganosolve pretreatments by ethanolysis and white rot fungi, Ceriporiopsis subvermispora, Dichomitus squalens, Pleurotus ostreatus, and Coriolus versicolor. Beech wood chips were pretreated with the white rot fungi for 2–8 weeks without addition of any nutrients. The wood chips were then subjected to ethanolysis to separate them into pulp and soluble fractions (SFs). From the pulp fraction (PF), ethanol was produced by SSF using Saccharomyces cerevisiae AM12 and a commercial cellulase preparation, Meicelase, from Trichoderma viride. Among the four strains, C. subvermispora gave the highest yield on SSF. The yield of ethanol obtained after pretreatment with C. subvermispora for 8 weeks was 0.294 g g−1 of ethanolysis pulp (74% of theoretical) and 0.176 g g−1 of beech wood chips (62% of theoretical). The yield was 1.6 times higher than that obtained without the fungal treatments. The biological pretreatments saved 15% of the electricity needed for the ethanolysis. [Copyright &y& Elsevier]

Significant contributions have been made to understand the ligninolytic system of the biopulping fungus, Ceriporiopsis subvermispora; however, the reason why this fungus selectively degrades lignin is still unclear. This study evaluates the depolymerization of wood components induced by C. subvermispora during wood decay under solid-state fermentation. Pinus taeda wood chips were biotreated for periods from 15 to 90 days. The fungus degraded lignin and extractives extensively without removing large amounts of glucan. Alpha-cellulose samples were prepared from decayed and undecayed wood chips for evaluation of cellulose depolymerization. The yields of alpha-cellulose decreased from 47.8% for undecayed wood to 42.6 and 34.2% for the wood samples biotreated for 30 and 90 days, respectively. High performance size exclusion chromatography of tricarbanyl derivatives of these alpha-cellulose preparations indicated a progressive decrease in the polymerization degree values from the 30th day of biotreatment. Lignin depolymerization, evaluated by gel permeation chromatography (GPC) of residual MWLs, was rapid in the first 30 days of biodegradation. After this period an extensive mineralization occurred. Some relevant hydrolytic and oxidative enzymes present in the culture extracts were studied. Xylanase was the main hydrolytic enzyme produced, while laccase was not detected in any biodegradation period evaluated. A correlation between the levels of wood-degrading enzymes produced and the pattern of wood constituents degradation was tentatively established. [Copyright &y& Elsevier]

The white-rot fungus Ceriporiopsis subvermispora grows on wood aggressively and is suitable for biopulping of both soft and hardwoods. This fungus is able to produce laccase and manganese peroxidase (MnP) isoenzymes, as well as hemicellulases and a poor complex of cellulases lacking in cellobiohydrolase activity. In the present work, C. subvermispora was grown on Eucalyptus grandis wood chips under solid-state fermentation. Wood weight loss ranged from 2.9 to 11.7% for biodegradation periods of 15–90 days. The highest lignin loss was 27 %, which was similar to the loss of polyoses (21.6%) after 90 days of treatment. Glucan loss started to be significant only after 60 days of biodegradation attaining a maximum of 7.3% after 90 days. Extractives removal was also significant, reaching 42% after 90 days. Holocellulose yields were almost unchanged over all the biodegradation periods. However, the holocellulose viscosities decreased as a function of the biodegradation time, especially after 30 days. The yields of alpha-cellulose decreased from 44 to 37% as a function of the biodegradation time, indicating that cellulose depolymerization took place even when the glucan losses were low. Some relevant hydrolytic and oxidative enzymes present in the culture extracts were studied. Xylanase was the main hydrolytic enzyme and the levels of peroxidase were lower than those of laccase. During the initial wood decay stages, there was not a direct correlation between the levels of enzymatic activities and the extent of losses of wood weight or components. This suggests that the mineralization of wood components might be limited by the non-diffusion of the enzymes into the wood cell walls at the initial decay stages. [Copyright &y& Elsevier]

• Wheat bran improves colonization of wheat straw by Ceriporiopsis subvermispora and Lentinula edodes. • The two fungal species degraded wheat bran starch clearly differently. • Supplementation with wheat bran had no effect on lignin degradation. A rapid and complete colonization of lignocellulosic biomass by white-rot fungi is a prerequisite for an efficient and contamination free delignification. To improve the colonization, mycelium growth and delignification by Ceriporiopsis subvermispora and Lentinula edodes of wheat straw, with addition of 2, 4, 6 and 10% of wheat bran for 0, 2, 4, 8 and 12 weeks, was evaluated. The ergosterol content, chemical composition and in vitro gas production (IVGP) by ruminal microorganisms were determined. The fungal biomass and starch amount was significantly (P < 0.001) affected by the inclusion level of wheat bran and incubation time. An increase in added wheat bran increased the fungal biomass with different effects observed for the two fungi. The added starch from the wheat bran was degraded by C. subvermispora , mainly during the first two weeks (up to 44%), whereas, L. edodes degraded starch during 12 weeks up to 83%. The supplementation of wheat bran, however, did not affect (P > 0.05) the amount of hemicellulose and lignin at the end of the incubation. There was no significant effect of wheat bran addition on the IVGP for the two fungal treatments. Supplementation of wheat straw with wheat bran resulted in a quicker fungal colonization, which is useful for C. subvermispora , a fungus that forms only thin mycelium and is more prone to contamination than L. edodes. [ABSTRACT FROM AUTHOR]