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Pink staining in shiitake (Lentinula edodes (Berk.) Pegler) billets (Quercus griffithii Hook.f. and Thomson ex Miq.) causing the inhibition of shiitake mycelium and a reduction in shiitake production was observed throughout Bhutan in 2017-2018. Completion of Koch's postulates confirmed the causal agent to be Scytalidium cuboideum, a first record of this disease in shiitake billets in Bhutan. In failed billets, it was observed that there was no growth of shiitake mycelium from the spawn. Trials suggest that S. cuboideum is responsible for the occurrences of poor colonisation by shiitake spawn--even when pink staining is not evident. Warm temperatures favour S. cuboideum, with shiitake able to sometimes overcome low rates of infection when incubated at low temperatures. [ABSTRACT FROM AUTHOR]

Pink staining in shiitake (Lentinula edodes (Berk.) Pegler) billets (Quercus griffithii Hook.f. and Thomson ex Miq.) causing the inhibition of shiitake mycelium and a reduction in shiitake production was observed throughout Bhutan in 2017–2018. Completion of Koch’s postulates confirmed the causal agent to be Scytalidium cuboideum, a first record of this disease in shiitake billets in Bhutan. In failed billets, it was observed that there was no growth of shiitake mycelium from the spawn. Trials suggest that S. cuboideum is responsible for the occurrences of poor colonisation by shiitake spawn—even when pink staining is not evident. Warm temperatures favour S. cuboideum, with shiitake able to sometimes overcome low rates of infection when incubated at low temperatures.

Pollution from the international dye industry continues to be a global problem. Biotechnology offers new options, including a closer look at select wood decay fungi to replace inorganic dyes. The pigments produced by a small group of soft rotting fungi are generally naphthoquinonic and remarkably stable. From this group, the dramada crystals, produced by Scytalidium cuboideum, are of particular interest. To test the application of this pigment as a natural colorant of cellulosic pulps, four different bleached pulps were selected (one hardwood, three softwood), in three different mediums (acetone, ethanol, and DI water). The pigment generated a significant change of color, but there was no significant difference in color intensity based on the solvent carrier. These preliminary results are promising as they open the door for further exploration of applications of fungal pigments in the paper industry. Once these pigments can be reliably grown, they will offer a sustainable organic alternative to polluting inorganic dyestuffs and help reduce the toxic effluent released into the soil and waterways. [ABSTRACT FROM AUTHOR]

Wood-staining fungal pigments have shown potential use as colorants for wood and textiles, with organic solvents as the pigment carrier. Natural oils have been suggested as an environmentally friendly and more available carrier; however, oils promoted color degradation. The current study examined the mechanism of said degradation and tested therapeutic and food-grade oils (instead of finishing oils) for their potential to carry draconin red, the pigment from Scytalidium cuboideum, without color loss over time. FTIR analysis from finishing oils indicated that oxidation was not likely the cause of color loss as the pigment could not be distinguished from the oils in the IR spectra. SEM was employed to determine if crystal degradation was contributing to color loss and indicated, surprisingly, that the crystals of draconin red formed rather than degraded over time. This suggested crystal breakdown was also not likely the cause of color loss. The pigment did not show degradation in hemp oil, flaxseed oil, and cold-pressed linseed oil when treated with β-carotene. Further in-depth chemical studies are needed to determine the mechanism of color loss in pigmented natural oils; however, food-grade oils appear to be a promising alternative to carry draconin red, without degradation of the color. [ABSTRACT FROM AUTHOR]

Pollution from the international dye industry continues to be a global problem. Biotechnology offers new options, including a closer look at select wood decay fungi to replace inorganic dyes. The pigments produced by a small group of soft rotting fungi are generally naphthoquinonic and remarkably stable. From this group, the dramada crystals, produced by Scytalidium cuboideum, are of particular interest. To test the application of this pigment as a natural colorant of cellulosic pulps, four different bleached pulps were selected (one hardwood, three softwood), in three different mediums (acetone, ethanol, and DI water). The pigment generated a significant change of color, but there was no significant difference in color intensity based on the solvent carrier. These preliminary results are promising as they open the door for further exploration of applications of fungal pigments in the paper industry. Once these pigments can be reliably grown, they will offer a sustainable organic alternative to polluting inorganic dyestuffs and help reduce the toxic effluent released into the soil and waterways.

Wood-staining fungal pigments have shown potential use as colorants for wood and textiles, with organic solvents as the pigment carrier. Natural oils have been suggested as an environmentally friendly and more available carrier; however, oils promoted color degradation. The current study examined the mechanism of said degradation and tested therapeutic and food-grade oils (instead of finishing oils) for their potential to carry draconin red, the pigment from Scytalidium cuboideum, without color loss over time. FTIR analysis from finishing oils indicated that oxidation was not likely the cause of color loss as the pigment could not be distinguished from the oils in the IR spectra. SEM was employed to determine if crystal degradation was contributing to color loss and indicated, surprisingly, that the crystals of draconin red formed rather than degraded over time. This suggested crystal breakdown was also not likely the cause of color loss. The pigment did not show degradation in hemp oil, flaxseed oil, and cold-pressed linseed oil when treated with β-carotene. Further in-depth chemical studies are needed to determine the mechanism of color loss in pigmented natural oils; however, food-grade oils appear to be a promising alternative to carry draconin red, without degradation of the color.

Spalting fungal pigments have shown potential in technologies ranging from green energy generation to natural colorants. However, their unknown toxicity has been a barrier to industrial adoption. In order to gain an understanding of the safety of the pigments, zebrafish embryos were exposed to multiple forms of liquid media and solvent-extracted pigments with concentrations of purified pigment ranging from 0 to 50 mM from Chlorociboria aeruginosa, Chlorociboria aeruginascens, and Scytalidium cuboideum. Purified xylindein from Chlorociboria sp. did not show toxicity at any tested concentration, while the red pigment dramada from S. cuboideum was only associated with significant toxicity above 23.2 uM. However, liquid cultures and pigment extracted into dichloromethane (DCM) showed toxicity, suggesting the co-production of bioactive secondary metabolites. Future research on purification and the bioavailability of the red dramada pigment will be important to identify appropriate use; however, purified forms of the blue-green pigment xylindein are likely safe for use across industries. This opens the door to the adoption of green technologies based on these pigments, with potential to replace synthetic colorants and less stable natural pigments. [ABSTRACT FROM AUTHOR]

Identification of effective natural dyes with the potential for low environmental impact has been a recent focus of the textile industry. Pigments derived from spalting fungi have previously shown promise as textile dyes; however, their use has required numerous organic solvents with human health implications. This research explored the possibility of using linseed oil as a carrier for the pigment from Scytalidium cuboideum as a textile dye. Colored linseed oil effectively dyed a range of fabrics, with natural fibers showing better coloration. Scanning electron microscopy (SEM) revealed a pigment film over the fabric surface. While mechanical testing showed no strength loss in treated fabric, colorfastness tests showed significant changes in color in response to laundering and bleach exposure with variable effects across fabric varieties. SEM investigation confirmed differences in pigmented oil layer loss and showed variation in pigment crystal formation between fabric varieties. Heating of the pigmented oil layer was found to result in a bright, shiny fabric surface, which may have potential for naturally weatherproof garments.

Pigments from wood-decay fungi (specifically spalting fungi) have a long history of use in wood art, and have become relevant in modern science due to their longevity and colorfastness. They are presently under investigation as colorants for wood, bamboo, oils, paints and textiles. Major hurdles to their commercialization have been color repeatability (in that the same strain of the same species of fungus may produce different colors over time), and the binding of the pigments to glass storage containers. This is persistent as they do not naturally exist in a loose form. Due to these issues, the ‘standard’ color for each was historically determined not by the amount of pigment, but by the color in a solution of dichloromethane (DCM), using the CIE L*a*b colorspace. This method of standardization severely limited the use of these pigments in industrial applications, as without a dry form, standard methodologies for repeatable color processing into other materials could not be easily implemented. Recent studies have developed a method to crystalize the red pigment from Scytalidium cuboideum (Sacc. & Ellis) Sigler & Kang, producing a highly pure (99%) solid crystal named ‘Dramada’. Herein a method is detailed to compare the molarity of this crystallized pigment to variations in the color, to determine a color saturation curve (by weight) for the pigment from S. cuboideum in DCM and acetone. The molarities for this experiment ranged from 0.024 mM to 19 mM. Each molarity was color read and assigned a CIEL*a*b* value. The results showed that there was a correlation between the molarity and color difference, with the maximum red color occurring between 0.73 mM and 7.3 mM in DCM and between 0.97 mM to 0.73 mM in acetone. Extremely low molarities of pigment produced strong coloration in the solvent, and changes in molarity significantly affected the color of the solution. Having a saturation and color curve for the crystal ‘Dramada’ from S. cuboideum will allow for the reliable production of distinct colors from a known quantity (by weight) of pigment, erasing the final hurdle towards commercial development of the crystallized pigment from S. cuboideum as an industrial dyestuff.

Intarsia was an art form popular between the 15th–18th centuries that used wood pigmented by spalting fungi to create detailed landscapes, portraits, and other imagery. These fungi are still used today in art but are also finding relevance in material science as elements of solar cells, textile dyes, and paint colorants. Here we show that the spalting fungus Scytalidium cuboideum (Sacc. and Ellis) Sigler and Kang produces a red/pink pigment that forms two distinct colors of crystals (red and orange)—a very rare occurrence. In addition, a second structure of the crystal is proved through nuclear magnetic resonance (NMR). This is only the second instance of a stable, naphthoquinone crystal produced by a fungus. Its discovery is particularly valuable for solar cell development, as crystalline materials have a higher electrical conductivity. Other fungi in this order have shown strong potential as thin films for solar cells.

The use of both naturally occurring and synthetic pigmented wood has been prevalent in woodcraft for centuries. Modern manifestations generally involve either woodworkers’ aniline dyes, or pigments derived from a special class of fungi known as spalting fungi. While fungal pigments are more renewable than anilines and pose less of an environmental risk, the carrier required for these pigments—dichloromethane (DCM)—is both problematic for humans and tends to only deposit the pigments on the surface of wood instead of evenly within the material. Internal coloration of wood is key to adoption of a pigmenting system by woodworkers. To address this issue, five solvents that had moderate solubility with the pigments extracted from Chlorociboria aeruginosa and Scytalidium cuboideum were identified, in the hopes that a reduction in solubility would result in a greater amount of the pigment deposited inside the wood. Of the tested solvents, acetonitrile was found to produce the highest internal color in ash, Douglas-fir, madrone, mountain hemlock, Port-Orford cedar, Pacific silver fir, red alder and sugar maple. While these carrier solvents are not ideal for extracting the pigments from the fungi, acetonitrile in particular does appear to allow for more pigment to be deposited within wood. The use of acetonitrile over DCM offers new opportunities for possible industrial spalting applications, in which larger pieces of wood could be uniformly pigmented and sold to the end user in larger quantities than are currently available with spalted wood.

Yellow rot, caused by an ascomycetous fungus having a distinctive arthroconidial anamorph, is the most destructive disease of cultivated Gano-derma lucidum in Korea, but the identity of the yellow rot pathogen (YRP) remains uncertain. Isolates have been identified as Xylogone sphaerospora (with putative anamorph Sporendonema purpurascens) or as Arthrographis cuboidea. Therefore we used morphological features, pathogenicity tests and phylogenetic analyses of DNA sequences from the nuclear ribosomal genes, including partial small subunit and internal transcribed spacer regions, and from the gene encoding RNA polymerase second largest subunit to evaluate the relationship between YRP isolates and these species. YRP isolates formed a distinct subgroup within a clade that included X sphaerospora, A. cuboidea and Scytalidium lignicola, the type species of Scytalidium, but the disposition of the clade within the Leotiomycetes was uncertain. We describe Xylogone ganodermophthora sp. nov. and Scytalidium ganodermophthorum sp. nov. for the teleomorph and anamorph of YRP respectively. Arthrographis cuboidea is reclassified as Scytalidium cuboideum comb, nov., and the anamorph of X. sphaerospora is named Scytalidium sphaerosporum sp. nov. In pathogenicity tests only X. ganodermophthora caused disease in Ganoderma lucidum. Amplified fragment length polymorphism analyses showed that X ganodermophthora populations from diseased fruiting bodies or from oak wood in Korea consisted of two clonal groups. [ABSTRACT FROM AUTHOR]

UV-light degradation of wood is one of the top reasons for consumer replacement of outdoor wooden structures. This type of degradation is seldom mechanical, and is instead often motivated by loss of aesthetics (graying). There are numerous commercial products available on the market that deal with this loss of color, many of which contain added pigments to 'rejuvenate' or 'revitalize' greyed wood. These pigments are almost uniformly synthetic. In contrast, pigments from wood decay fungi (spalting), which have been used in woodworking since the 1400s (intarsia), have remarkable optical (UV-light resistance) properties due to their naphthoquinonic configuration. In recent years the pigments made from these fungi have been extracted and tested across numerous substrates, from solar cells to textile dyes. In this work, researchers extracted pigments from Scytalidium cuboideum (red pigmentation) and Chlorociboria aeruginosa (blue-green pigmentation), solubilized the pigments in raw linseed oil, and tested the resulting solution on samples of Douglas-fir (Pseudotsuga menziesii) and western white pine (Pinus monticola). These mixtures were compared against a 'stain and coat' treatment (utilizing an aniline stain and coated with raw linseed oil), raw linseed oil, and untreated wood. The wood samples were then placed in an accelerated weathering machine (Q-UV) following the ASTM G154 standard, for 500 and 1000 h. The results showed that while no visible color change occurred to the wood when the pigmented oil was applied, the red pigment oil significantly lowered the coating degradation for both wood types at an exposure of 500 h. The results show the potential applications for fungal pigments in the wood coating industry, as it offers an increased coating service life. As there is a shift to renewable products, the pigments from wood decay fungi show potential as additives for wood coatings. [ABSTRACT FROM AUTHOR]

Abstract: Deciduous wood pigmented by fungi (spalted wood) has a long history of use in decorative woodcraft dating back to at least the 15th century and is still routinely utilized by woodworkers today. With the prevalence of the mountain pine beetle in western North America, a large amount of bluestained wood is currently available but is not utilized for value-added applications like spalting. This study shows that bluestained lodgepole pine is an ideal wood for additional spalting treatment with Scytalidium species, resulting in additional pigments of pink or yellow on the wood. The results of this study show that not only can coniferous wood be spalted, but that bluestained pine is particularly well suited for additional pigmentation. Brightly pigmented spalted wood is rare within the current marketplace and offers a new potential market for bluestained lumber and a chance for areas affected by mountain pine beetle to recapture lost income from their forest stock. [Copyright &y& Elsevier]

Spalting fungal pigments have shown potential in technologies ranging from green energy generation to natural colorants. However, their unknown toxicity has been a barrier to industrial adoption. In order to gain an understanding of the safety of the pigments, zebrafish embryos were exposed to multiple forms of liquid media and solvent-extracted pigments with concentrations of purified pigment ranging from 0 to 50 mM from Chlorociboria aeruginosa, Chlorociboria aeruginascens, and Scytalidium cuboideum. Purified xylindein from Chlorociboria sp . did not show toxicity at any tested concentration, while the red pigment dramada from S. cuboideum was only associated with significant toxicity above 23.2 uM. However, liquid cultures and pigment extracted into dichloromethane (DCM) showed toxicity, suggesting the co-production of bioactive secondary metabolites. Future research on purification and the bioavailability of the red dramada pigment will be important to identify appropriate use; however, purified forms of the blue-green pigment xylindein are likely safe for use across industries. This opens the door to the adoption of green technologies based on these pigments, with potential to replace synthetic colorants and less stable natural pigments.

Identification of effective natural dyes with the potential for low environmental impact has been a recent focus of the textile industry. Pigments derived from spalting fungi have previously shown promise as textile dyes; however, their use has required numerous organic solvents with human health implications. This research explored the possibility of using linseed oil as a carrier for the pigment from Scytalidium cuboideum as a textile dye. Colored linseed oil effectively dyed a range of fabrics, with natural fibers showing better coloration. Scanning electron microscopy (SEM) revealed a pigment film over the fabric surface. While mechanical testing showed no strength loss in treated fabric, colorfastness tests showed significant changes in color in response to laundering and bleach exposure with variable effects across fabric varieties. SEM investigation confirmed differences in pigmented oil layer loss and showed variation in pigment crystal formation between fabric varieties. Heating of the pigmented oil layer was found to result in a bright, shiny fabric surface, which may have potential for naturally weatherproof garments., Competing Interests: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

Pigments from wood-decay fungi (specifically spalting fungi) have a long history of use in wood art, and have become relevant in modern science due to their longevity and colorfastness. They are presently under investigation as colorants for wood, bamboo, oils, paints and textiles. Major hurdles to their commercialization have been color repeatability (in that the same strain of the same species of fungus may produce different colors over time), and the binding of the pigments to glass storage containers. This is persistent as they do not naturally exist in a loose form. Due to these issues, the 'standard' color for each was historically determined not by the amount of pigment, but by the color in a solution of dichloromethane (DCM), using the CIE L*a*b colorspace. This method of standardization severely limited the use of these pigments in industrial applications, as without a dry form, standard methodologies for repeatable color processing into other materials could not be easily implemented. Recent studies have developed a method to crystalize the red pigment from Scytalidium cuboideum (Sacc. & Ellis) Sigler & Kang, producing a highly pure (99%) solid crystal named 'Dramada'. Herein a method is detailed to compare the molarity of this crystallized pigment to variations in the color, to determine a color saturation curve (by weight) for the pigment from S. cuboideum in DCM and acetone. The molarities for this experiment ranged from 0.024 mM to 19 mM. Each molarity was color read and assigned a CIEL*a*b* value. The results showed that there was a correlation between the molarity and color difference, with the maximum red color occurring between 0.73 mM and 7.3 mM in DCM and between 0.97 mM to 0.73 mM in acetone. Extremely low molarities of pigment produced strong coloration in the solvent, and changes in molarity significantly affected the color of the solution. Having a saturation and color curve for the crystal 'Dramada' from S. cuboideum will allow for the reliable production of distinct colors from a known quantity (by weight) of pigment, erasing the final hurdle towards commercial development of the crystallized pigment from S. cuboideum as an industrial dyestuff. [ABSTRACT FROM AUTHOR]

Intarsia was an art form popular between the 15th–18th centuries that used wood pigmented by spalting fungi to create detailed landscapes, portraits, and other imagery. These fungi are still used today in art but are also finding relevance in material science as elements of solar cells, textile dyes, and paint colorants. Here we show that the spalting fungus Scytalidium cuboideum (Sacc. and Ellis) Sigler and Kang produces a red/pink pigment that forms two distinct colors of crystals (red and orange)—a very rare occurrence. In addition, a second structure of the crystal is proved through nuclear magnetic resonance (NMR). This is only the second instance of a stable, naphthoquinone crystal produced by a fungus. Its discovery is particularly valuable for solar cell development, as crystalline materials have a higher electrical conductivity. Other fungi in this order have shown strong potential as thin films for solar cells. [ABSTRACT FROM AUTHOR]

The use of both naturally occurring and synthetic pigmented wood has been prevalent in woodcraft for centuries. Modern manifestations generally involve either woodworkers’ aniline dyes, or pigments derived from a special class of fungi known as spalting fungi. While fungal pigments are more renewable than anilines and pose less of an environmental risk, the carrier required for these pigments—dichloromethane (DCM)—is both problematic for humans and tends to only deposit the pigments on the surface of wood instead of evenly within the material. Internal coloration of wood is key to adoption of a pigmenting system by woodworkers. To address this issue, five solvents that had moderate solubility with the pigments extracted from Chlorociboria aeruginosa and Scytalidium cuboideum were identified, in the hopes that a reduction in solubility would result in a greater amount of the pigment deposited inside the wood. Of the tested solvents, acetonitrile was found to produce the highest internal color in ash, Douglas-fir, madrone, mountain hemlock, Port-Orford cedar, Pacific silver fir, red alder and sugar maple. While these carrier solvents are not ideal for extracting the pigments from the fungi, acetonitrile in particular does appear to allow for more pigment to be deposited within wood. The use of acetonitrile over DCM offers new opportunities for possible industrial spalting applications, in which larger pieces of wood could be uniformly pigmented and sold to the end user in larger quantities than are currently available with spalted wood. [ABSTRACT FROM AUTHOR]