Loxoprofen has been widely used as a non-steroidal anti-inflammatory drug globally and it can also persist in the environment. Although it is known to be a non-toxic drug, its presence may still pose a potential risk to organisms in the environment. Here, the hyper lignin-degrading fungus Phanerochaete sordida YK-624 was used to study the degradation of loxoprofen. This fungus showed excellent loxoprofen biodegradation ability with 90.4% and 93.4% after one day of incubation at lower concentrations of 0.01 and 0.005 mM, respectively. And at a higher concentration of 0.1 mM, a significant removal of 94.2% was also observed after 10 days of incubation. In this study, four metabolites were isolated and determined by HR-ESI-MS and NMR. Furthermore, LC/MS analysis suggested the presence of intermediate hydroxy loxoprofen. In addition, loxoprofen-OH was also identified as a metabolite of loxoprofen through comparison with the synthesized compounds. In this metabolism of loxoprofen, cytochrome P450 may play a significant role. Interestingly, P. sordida YK-624 showed enantioselectivity in the degradation process of loxoprofen. By these results, three degradation pathways of loxoprofen by P. sordida YK-624 were hypothesized. To the best of our knowledge, this is the first report describing the potential degradation mechanisms of loxoprofen by a white-rot fungus.

Polycyclic aromatic hydrocarbons (PAHs) are a class of persistent organic pollutants with carcinogenic, mutagenic and teratogenic effects. The white-rot fungi in the fungal group have significant degradation ability for high molecular weight organic pollutants. However, exogenous fungi are easily antagonized by indigenous microorganisms. Low molecular weight organic acids, a small molecular organic matter secreted by plants, can provide carbon sources for soil microorganisms. Combining organic acids with white rot fungi may improve the nutritional environment of fungi. In this study, immobilized Trametes versicolor was used to degrade benzo[a]pyrene in soil, and its effect on removing benzo[a]pyrene in soil mediated by different low molecular weight organic acids was investigated. The results showed that when the degradation was 35 days, the removal effect of the experimental group with citric acid was the best, reaching 43.7%. The degradation effect of Trametes versicolor on benzo[a]pyrene was further investigated in the liquid medium when citric acid was added, and the effects of citric acid on the biomass, extracellular protein concentration and laccase activity of Trametes versicolor were investigated by controlling different concentrations of citric acid. In general, citric acid can act as a carbon source for Trametes versicolor and promote its extracellular protein secretion and laccase activity, thereby accelerating the mineralization of benzo[a]pyrene by Trametes versicolor. Therefore, citric acid can be used as a biostimulant in the remediation of PAHs contaminated soil with Trametes versicolor.

White-rot fungi differentially express laccases when they encounter aromatic compounds. However, the underlying mechanisms are still being explored. Here, proteomics analysis revealed that in addition to increased laccase activity, proteins involved in sphingolipid metabolism and toluene degradation as well as some cytochrome P450s (CYP450s) were differentially expressed and significantly enriched during 48 h of o-toluidine exposure, in Trametes hirsuta AH28-2. Two Zn2Cys6-type transcription factors (TFs), TH8421 and TH4300, were upregulated. Bioinformatics docking and isothermal titration calorimetry assays showed that each of them could bind directly to o-toluidine and another aromatic monomer, guaiacol. Binding to aromatic compounds promoted the formation of TH8421/TH4300 heterodimers. TH8421 and TH4300 silencing in T. hirsuta AH28-2 led to decreased transcriptional levels and activities of LacA and LacB upon o-toluidine and guaiacol exposure. EMSA and ChIP-qPCR analysis further showed that TH8421 and TH4300 bound directly with the promoter regions of lacA and lacB containing CGG or CCG motifs. Furthermore, the two TFs were involved in direct and positive regulation of the transcription of some CYP450s. Together, TH8421 and TH4300, two key regulators found in T. hirsuta AH28-2, function as heterodimers to simultaneously trigger the expression of downstream laccases and intracellular enzymes. Monomeric aromatic compounds act as ligands to promote heterodimer formation and enhance the transcriptional activities of the two TFs.IMPORTANCEWhite-rot fungi differentially express laccase isoenzymes when exposed to aromatic compounds. Clarification of the molecular mechanisms underlying differential laccase expression is essential to elucidate how white-rot fungi respond to the environment. Our study shows that two Zn2Cys6-type transcription factors form heterodimers, interact with the promoters of laccase genes, and positively regulate laccase transcription in Trametes hirsuta AH28-2. Aromatic monomer addition induces faster heterodimer formation and rate of activity. These findings not only identify two new transcription factors involved in fungal laccase transcription but also deepen our understanding of the mechanisms underlying the response to aromatics exposure in white-rot fungi.

Since the environmentally friendly reuse of corn stalks attracts more and more attention, it is an efficient and feasible way to reuse corn stalks as forage. However, whether the cellulose, lignin, and hemicellulose within corn stalks can be effectively decomposed becomes a key to reusing corn stalks as forage. Orthogonal test was designed by five different degradation temperatures (22°C, 24°C, 26°C, 28°C, 30°C), five different pH values (4, 5, 6, 8, 10), and five different degradation time durations (5, 15, 25, 30, and 35 days) to examine 25 kinds of different degradation conditions. It was found that the decomposition effect of hemicellulose, cellulose, and lignin, of group 25 (26°C, pH = 5, 25 days) was stronger compared with other groups, with the contents calculated as 8.22%, 31.55%, and 22.55% individually (p < 0.01, p < 0.05). Group 19 (22°C, pH = 4, 5 days) revealed the worst degradation effect of cellulose, lignin, and hemicellulose compared to other groups, with contents calculated as 15.48%, 38.85%, and 29.57%, individually (p < 0.01, p < 0.05). The research data deliver a basis for ideal degradation conditions for corn stalks degradation in combination with the digestive enzymes of P. chrysosporium and O. furnacalis larva. Aiming to explore a highly efficient and environmentally friendly corn stalk degradation method.

To fully harness the potential of laccase in the efficient decolorization and detoxification of single and mixed dyes with diverse chemical structures, we carried out a systematic study on the decolorization and detoxification of single and mixed dyes using a crude laccase preparation obtained from a white-rot fungus strain, Pleurotus eryngii. The crude laccase preparation showed efficient decolorization of azo, anthraquinone, triphenylmethane, and indigo dyes, and the reaction rate constants followed the order Remazol Brilliant Blue R > Bromophenol blue > Indigo carmine > New Coccine > Reactive Blue 4 > Reactive Black 5 > Acid Orange 7 > Methyl green. This laccase preparation exhibited notable tolerance to SO42- salts such as MnSO4, MgSO4, ZnSO4, Na2SO4, K2SO4, and CdSO4 during the decolorization of various types of dyes, but was significantly inhibited by Cl- salts. Additionally, this laccase preparation demonstrated strong tolerance to some organic solvents such as glycerol, ethylene glycol, propanediol, and butanediol. The crude laccase preparation demonstrated the efficient decolorization of dye mixtures, including azo + azo, azo + anthraquinone, azo + triphenylmethane, anthraquinone + indigo, anthraquinone + triphenylmethane, and indigo + triphenylmethane dyes. The decolorization kinetics of mixed dyes provided preliminary insight into the interactions between dyes in the decolorization process of mixed dyes, and the underlying reasons and mechanisms were discussed. Importantly, the crude laccase from Pleurotus eryngii showed efficient repeated-batch decolorization of single-, two-, and four-dye mixtures. This crude laccase demonstrated high stability and reusability in repeated-batch decolorization. Furthermore, this crude laccase was efficient in the detoxification of different types of single dyes and mixed dyes containing different types of dyes, and the phytotoxicity of decolorized dyes (single and mixed dyes) was significantly reduced. The crude laccase efficiently eliminated phytotoxicity associated with single and mixed dyes. Consequently, the crude laccase from Pleurotus eryngii offers significant potential for practical applications in the efficient decolorization and management of single and mixed dye pollutants with different chemical structures.

Synergistic microbial co-culture has been an efficient and energy-saving strategy to produce lignin-degrading enzymes (LDEs), including laccase, manganese peroxidase, and versatile peroxidase. However, the regulatory mechanism of microbial co-culture is still unclear. Herein, the extracellular LDE activities of four white-rot fungi were significantly increased by 88-544% over monoculture levels when co-cultured with Rhodotorula mucilaginosa. Ptf6 was demonstrated from the 9 million Y1H clone library to be a shared GATA transcription factor in the four fungi, and could directly bind to the laccase gene promoter. Ptf6 exists in two alternatively spliced isoforms under monoculture, namely Ptf6-α (1078 amino acids) containing Cys2/Cys2-type zinc finger and Ptf6-β (963 amino acids) lacking the complete domain. Ptf6 responded to co-culture by up-regulation of both its own transcripts and the proportion of Ptf6-α. Ptf6-α positively activated the production of most LDE isoenzymes and bound to four GATA motifs on the LDEs\' promoter with different affinities. Moreover, Ptf6-regulation mechanism can be applicable to a variety of microbial co-culture systems. This study lays a theoretical foundation for further improving LDEs production and providing an efficient way to enhance the effects of biological and enzymatic pretreatment for lignocellulosic biomass conversion.

White-rot fungi are the most important group of lignin biodegraders. Phanerochaete sordida YK-624 has higher ligninolytic activity than that of model white-rot fungi. However, the underlying mechanism responsible for lignin degradation by white-rot fungi remains unknown, and the induced compounds isolated from white-rot fungi for lignin degradation have never been studied. In the present study, we tried to screen ligninolytic-inducing compounds produced by P. sordida YK-624. After large-scale incubation of P. sordida YK-624, the culture and mycelium were separated by filtration. After the separation and purification, purified compounds were analyzed by high-resolution electrospray ionization mass spectrometry and nuclear magnetic resonance. The sterilized unbleached hardwood kraft pulp was used for the initial evaluation of ligninolytic activity. Ergosterol was isolated and identified and it induced the lignin-degrading activity of this fungus. Moreover, we investigated ergosterol metabolites from P. sordida YK-624, and the ergosterol metabolites ergosta-4,7,22-triene-3,6-dione and ergosta-4,6,8(14),22-tetraen-3-one were identified and then chemically synthesized. These compounds significantly improved the lignin-degrading activity of the fungus. This is the first report on the ligninolytic-inducing compounds produced by white-rot fungi.

Azo dyes are widely used in textile, paper and packing industries, and have become one of the research hot spots in dye wastewater treatment because of their carcinogenicity, teratogenic mutagenicity, stable structure and degradation difficulty. In this study, the biodecolorization of acid orange 7 (AO7), an azo dye, by different white rot fungi was investigated, and the effect of different conditions on the decolorization rate of the dye was analyzed. At the same time, the degradation liquor was analyzed and the phytotoxicity experiment was performed to deduce the possible degradation pathway of AO7 and assess the toxicity of its degradation products. The results showed that the decolorization rate reached 93.46% in 24 h at pH 4.5, 28 ℃ by Pleurotus eryngii and Trametes versicolor when AO7 concentration was 100 mg/L. The biodegradation pathway of AO7 was initiated by the cleavage of the azo bond of AO7, generating p-aminobenzenesulfonic acid and 1-amino-2-naphthol. Subsequently, the sulfonic acid group of p-aminobenzene sulfonic acid was removed to generate hydroquinone. Moreover, the 1-amino-2-naphthol was de-ringed to generate phthalic acid and p-hydroxybenzaldehyde, and then further degraded into benzoic acid. Finally, hydroquinone and benzoic acid may be further oxidized into other small molecules, carbon dioxide and water. Phytotoxicity experiment showed that the toxicity of AO7 could be reduced by P. eryngii and T. versicolor.

As human society and industrialization have progressed, harmful algal blooms have contributed to global ecological pollution which makes the development of a novel and effective algal control strategy imminent. This is because existing physical and chemical methods for dealing with the problem have issues like cost and secondary pollution. Benefiting from their environmentally friendly and biocompatible properties, white-rot fungi (WRF) have been studied to control algal growth. WRF control algae by using algae for carbon or nitrogen, antagonism, and enhancing allelopathies. It can be better applied to practice by immobilization. This paper reviews the mechanism for WRF control of algae growth and its practical application. It demonstrates the limitations of WRF controlling algae growth and aids the further study of biological methods to regulate eutrophic water in algae growth research. In addition, it provides theoretical support for the fungi controlling algae growth.

Wood-inhabiting fungi are abundant in China, but their distribution is uneven, with more fungi in southwest China and fewer fungi in northwest China. During the investigation of wood-inhabiting fungi in Xinjiang, we collected a large number of specimens. Eight specimens growing on Piceaschrenkiana were collected from Tianshan Mountains, and they were described as two new species in Ceriporiopsis and Sidera based on morphological characters and molecular evidence. Ceriporiopsistianshanensis is characterized by a cream to salmon-buff pore surface, larger pores measuring 1-3 per mm, and broadly ellipsoid basidiospores 5-6.5 × 3-4 μm. Sideratianshanensis is characterized by annual to perennial basidiocarps, measuring 15 mm thick, pores 5-7 per mm, cream to rosy buff pore surface, and allantoid basidiospores 3-3.5 × 1-1.4 µm. Detailed illustrations and descriptions of the novel species are provided.