Exploring the formation of heterodimers of barley hydroxycinnamoylagmatines by oxidative enzymes.

Dimers of hydroxycinnamoylagmatines are phenolic compounds found in barley and beer. Although they are bioactive and sensory-active compounds, systematic reports on their structure-property relationships are missing. This is partly due to lack of protocols to obtain a diverse set of hydroxycinnamoylagmatine homo- and heterodimers. To better understand dimer formation in complex systems, combinations of the monomers coumaroylagmatine (CouAgm), feruloylagmatine (FerAgm), and sinapoylagmatine (SinAgm) were incubated with horseradish peroxidase. For all combinations, the main oxidative coupling products were homodimers. Additionally, minor amounts of heterodimers were formed, except for the combination of FerAgm and CouAgm. Oxidative coupling was also performed with laccases from Agaricus bisporus and Trametes versicolor, resulting in formation of the same coupling products and no formation of CouAgm-FerAgm heterodimers. Our protocol for oxidative coupling combinations of hydroxycinnamoylagmatines yielded a structurally diverse set of coupling products, facilitating production of dimers for future research on their structure-property relationships.

Identification of redox activators for continuous reactivation of glyoxal oxidase from Trametes versicolor in a two-enzyme reaction cascade.

Glyoxal oxidases, belonging to the group of copper radical oxidases (CROs), oxidize aldehydes to carboxylic acids, while reducing O2 to H2O2. Their activity on furan derivatives like 5-hydroxymethylfurfural (HMF) makes these enzymes promising biocatalysts for the environmentally friendly synthesis of the bioplastics precursor 2,5-furandicarboxylic acid (FDCA). However, glyoxal oxidases suffer from inactivation, which requires the identification of suitable redox activators for efficient substrate conversion. Furthermore, only a few glyoxal oxidases have been expressed and characterized so far. Here, we report on a new glyoxal oxidase from Trametes versicolor (TvGLOX) that was expressed at high levels in Pichia pastoris (reclassified as Komagataella phaffii). TvGLOX was found to catalyze the oxidation of aldehyde groups in glyoxylic acid, methyl glyoxal, HMF, 2,5-diformylfuran (DFF) and 5-formyl-2-furancarboxylic acid (FFCA), but barely accepted alcohol groups as in 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), preventing formation of FDCA from HMF. Various redox activators were tested for TvGLOX reactivation during catalyzed reactions. Among them, a combination of horseradish peroxidase and its substrate 2,2'-azino-di-(3-ethylbenzthiazoline sulfonic acid) (ABTS) most efficiently reactivated TvGLOX. Through continuous reactivation of TvGLOX in a two-enzyme system employing a recombinant Moesziomyces antarcticus aryl-alcohol oxidase (MaAAO) almost complete conversion of 8 mM HMF to FDCA was achieved within 24 h.

Under explored roles of microbial ligninolytic enzymes in aerobic polychlorinated biphenyl transformation.

Polychlorinated biphenyls (PCBs) are persistent organic pollutants in the environment that are responsible for many adverse health effects. Bioremediation appears to be a healthy and cost-effective alternative for remediating PCB-contaminated environments. While some microbial species have been observed to be capable of transforming PCBs, only two different microbial pathways (rdh and bph pathways) have been described to be involved in PCB transformations. Ligninolytic enzymes have been observed or are under suspicion in some microbial PCB transformations. However, the role of these promising PCB-transforming enzymes, which are produced by fungi and some aerobic bacteria, is still unclear. The present review describes their role by identifying microbial PCB-transforming species and their reported ligninolytic enzymes whether proven or suspected to be involved in PCB transformations. There are several lines of evidence that ligninolytic enzymes are responsible for PCB transformations such as (1) the ability of purified laccases from Myceliophthora thermophila, Pycnoporus cinnabarinus, Trametes versicolor, Cladosporium sp, and Coprinus cumatus to transform hydroxy-PCBs; (2) the increased production of laccases and peroxidases by many fungi in the presence of PCBs; and (3) the enhanced PCB transformation by Pseudomonas stutzeri and Sinorhizobium meliloti NM after the addition of ligninolytic enzyme enhancers. However, if the involvement of ligninolytic enzymes in PCB transformation is clearly demonstrated in some fungal species, it does not seem to be implicated in all microbial species suggesting other still unknown metabolic pathways involved in PCB transformation and different from the bph and rdh pathways. Therefore, PCB transformation may involve several metabolic pathways, some involving ligninolytic enzymes, bph or rdh genes, and some still unknown, depending on the microbial species. In addition, current knowledge does not fully clarify the role of ligninolytic enzymes in PCB oxidation and dechlorination. Therefore, further studies focusing on purified ligninolytic enzymes are needed to clearly elucidate their role in PCB transformation.

Immobilization of recombinant Trametes versicolor aflatoxin B1-degrading enzyme (TV-AFB1D) with montmorillonite for absorption and in situ degradation of aflatoxin B1.

Aflatoxin B1 is a highly carcinogenic and teratogenic substance mainly produced by toxin-producing strains such as Aspergillus flavus and Aspergillus parasitic. The efficient decomposition of aflatoxin is an important means to reduce its harm to humans and livestock. In this study, Trametes versicolor aflatoxin B1-degrading enzyme (TV-AFB1D) was recombinantly expressed in Bacillus subtilis (B. subtilis) 168. MMT-CTAB-AFB1D complex was prepared by the immobilization of TV-AFB1D and montmorillonite (MMT) by cross-linking glutaraldehyde. The results indicated that TV-AFB1D could recombinantly express in engineered B. subtilis 168 with a size of approximately 77 kDa. The immobilization efficiency of MMT-CTAB-AFB1D reached 98.63% when the concentration of glutaraldehyde was 5% (v/v). The relative activity of TV-AFB1D decreased to 72.36% after reusing for 10 times. The content of AFB1 in MMT-CTAB-AFB1D-AFB1 decreased to 1.1 µg/g from the initial 5.6 µg/g after incubation at 50 °C for 6 h. The amount of 80.4% AFB1 in the MMT-CTAB-AFB1D-AFB1 complex was degraded by in situ catalytic degradation. Thus, the strategy of combining adsorption and in situ degradation could effectively reduce the content of AFB1 residue in the MMT-CTAB-AFB1D complex.

Genome-wide screen identifies new set of genes for improved heterologous laccase expression in Saccharomyces cerevisiae.

The yeast Saccharomyces cerevisiae is widely used as a host cell for recombinant protein production due to its fast growth, cost-effective culturing, and ability to secrete large and complex proteins. However, one major drawback is the relatively low yield of produced proteins compared to other host systems. To address this issue, we developed an overlay assay to screen the yeast knockout collection and identify mutants that enhance recombinant protein production, specifically focusing on the secretion of the Trametes trogii fungal laccase enzyme. Gene ontology analysis of these mutants revealed an enrichment of processes including vacuolar targeting, vesicle trafficking, proteolysis, and glycolipid metabolism. We confirmed that a significant portion of these mutants also showed increased activity of the secreted laccase when grown in liquid culture. Notably, we found that the combination of deletions of OCA6, a tyrosine phosphatase gene, along with PMT1 or PMT2, two genes encoding ER membrane protein-O-mannosyltransferases involved in ER quality control, and SKI3, which encode for a component of the SKI complex responsible for mRNA degradation, further increased secreted laccase activity. Conversely, we also identified over 200 gene deletions that resulted in decreased secreted laccase activity, including many genes that encode for mitochondrial proteins and components of the ER-associated degradation pathway. Intriguingly, the deletion of the ER DNAJ co-chaperone gene SCJ1 led to almost no secreted laccase activity. When we expressed SCJ1 from a low-copy plasmid, laccase secretion was restored. However, overexpression of SCJ1 had a detrimental effect, indicating that precise dosing of key chaperone proteins is crucial for optimal recombinant protein expression. This study offers potential strategies for enhancing the overall yield of recombinant proteins and provides new avenues for further research in optimizing protein production systems.

Toward a zero waste approach: Utilization of sugarcane bagasse for dye removal and multienzymes production.

Global production of sugarcane bagasse (SB) by sugar industries exceeds more than 100 tons per annum. SB is rich in lignin and polysaccharide and hence can serve as a low-cost energy and carbon source for the growth of industrially important microorganism. However, various other applications of SB have also been investigated. In this study, SB was used as an adsorbent to remove an azo dye, malachite green. Subsequently, the dye-adsorbed SB was fermented by Trametes pubescens MB 89 for the production of laccase enzyme. The fungal pretreated SB was further utilized as a substrate for the simultaneous production of multiple plant cell wall degrading enzymes including, cellulase, xylanase, pectinase, and amylase by thermophilic bacterial strains. Results showed that 0.1% SB removed 97.04% malachite green at 30°C after 30 min from a solution containing 66 ppm of the dye. Fermentation of the dye-adsorbed SB by T. pubescens MB 89 yielded 667.203 IU mL-1 laccase. Moreover, Brevibacillus borstelensis UE10 produced 38.41 and 18.6 IU mL-1 ß-glucosidase and pectinase, respectively, by using fungal-pretreated SB. Cultivation of B. borstelensis UE27 in the medium containing the same substrate yielded 32.14 IU mL-1 of endoglucanase and 27.23 IU mL-1 of ß-glucosidase. Likewise, Neobacillus sedimentimangrovi UE25 could produce a mix of ß-glucosidase (37.24 IU mL-1 ), xylanase (18.65 IU mL-1 ) and endoglucanase (26.65 IU mL-1 ). Hence, this study led to the development of a method through which dye-containing textile effluent can be treated by SB along with the production of industrially important enzymes.

Optimizing the degradation of aflatoxin B1 in corn by Trametes versicolor and improving the nutritional composition of corn.

BACKGROUND: Corn, being an important grain, is prone to contamination by aflatoxin B1 (AFB1 ), and AFB1 -contaminated corn severely endangers the health of humans and livestock. Trametes versicolor, a fungus that can grow in corn, possesses the ability to directly degrade AFB1 through its laccase. This study aimed to optimize the fermentation conditions for T. versicolor to degrade AFB1 in corn and investigate the effect of T. versicolor fermentation on the nutritional composition of corn. AFB1 -contaminated corn was used as the culture substrate for T. versicolor. A combination of single-factor experiments and response surface methodology was employed to identify the optimal conditions of AFB1 degradation. RESULTS: The optimal conditions of AFB1 degradation were as follows: 9 days of fermentation, a fermentation temperature of 26.7 °C, a moisture content of 70.5% and an inoculation amount of 4.9 mL (containing 51.99 mg of T. versicolor mycelia). With the optimal conditions, the degradation rate of AFB1 in corn could reach 93.01%, and the dry basis content of protein and dietary fiber in the fermented corn was significantly increased. More importantly, the lysine content in the fermented corn was also significantly increased. CONCLUSION: This is the first report that direct fermentation of AFB1 -contaminated corn by T. versicolor not only efficiently degrades AFB1 but also improves the nutritional composition of corn. These findings suggest that the fermentation of corn by T. versicolor is a promising, environmentally friendly and efficient approach to degrade AFB1 and improve the nutritional value of corn. © 2023 Society of Chemical Industry.

Bioremediation of Diesel-Contaminated Soil by Fungal Solid-State Fermentation.

To address the poor removal of diesel in soil by indigenous microorganisms, we proposed a fungal solid-state fermentation (SSF) method for bioremediation. We screened Pycnoporus sanguineus 5.815, Trametes versicolor 5.996, and Trametes gibbosa 5.952 for their diesel-degrading abilities, with Trametes versicolor 5.996 showing the most promise. The fungal inoculum was obtained through SSF using wood chips and bran. Trametes versicolor 5.996 was applied to two treatments: natural attenuation (NA, diesel-contaminated soil) and bioremediation (BR, 10% SSF added to diesel-contaminated soil). Over 20 days, NA removed 12.9% of the diesel, while BR achieved a significantly higher 38.3% degradation rate. BR also increased CO2 and CH4 emissions but reduced N2O emissions. High-throughput sequencing indicated SSF significantly enriched known diesel-degrading microorganisms like Ascomycota (83.82%), Proteobacteria (46.10%), Actinobacteria (27.88%), Firmicutes (10.35%), and Bacteroidota (4.66%). This study provides theoretical support for the application of fungal remediation technology for diesel and improves understanding of microbiologically mediated diesel degradation and soil greenhouse gas emissions.

Direct arene trifluoromethylation enabled by promiscuous activity of fungal laccase.

Laccase from Trametes versicolor was found to oxidize non-phenolic arenes and enable the trifluoromethylation of arenes in the presence of in situ generated CF3 radicals at a catalyst loading as low as 0.0034%. The biocatalytic trifluoromethylation proceeded under mild conditions and could increase the yield by up to 12 fold, compared to the control.

Characterization of white rot fungi from wood decayed for lignin degradation.

The present study was conducted to isolate and identify white rot fungi (WRF) from wood decayed and to determine their ability to produce lignin-modifying enzymes (LMEs), specifically laccase (Lac), lignin peroxidase (LiP), and manganese peroxidase (MnP), on solid and liquid media supplemented with synthetic dyes namely 2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), azure B, and phenol red. A total of 23 isolates of WRF were isolated from decayed wood and identified as eight different species namely Phanerochaete australis, Perenniporia tephropora, Lentinus squarrosulus, Ganoderma australe, Trametes polyzona, Lentinus sajor-caju, Gymnopilus dilepis, and Fomitopsis palustris based on morphological characteristics, DNA sequences of the internal transcribed spacer (ITS) region, and phylogenetic inference. The fungal isolates can be divided into four groups based on the type of LMEs produced, namely A (Lac-LiP-MnP) with 16 isolates, B (Lac-MnP) (three isolates), C (Lac) (three isolates), and D (MnP) (one isolate). This study highlights P. australis (BJ38) as the best producer of Lac and LiP, while L. squarrosulus (IPS72) is the best producer of MnP. The present study is the first reported P. australis as an efficient lignin degrader by demonstrating the highest activity of two important LMEs.

Mechanistic Insights into the Biodegradation of Carbon Dots by Fungal Laccase.

While carbon dots (CDs) have the potential to support the agricultural revolution, it remains obscure about their environmental fate and bioavailability by plants. Fungal laccase-mediated biotransformation of carbon nanomaterials has received little attention despite its known capacity to eliminate recalcitrant contaminants. Herein, we presented the initial investigation into the transformation of CDs by fungal laccase. The degradation rates of CDs were determined to be first-order in both substrate and enzyme. Computational docking studies showed that CDs preferentially bonded to the pocket of laccase on the basal plane rather than the edge through hydrogen bonds and hydrophobic interactions. Electrospray ionization-Fourier transform-ion cyclotron resonance mass spectrometry (ESI-FT-ICR MS) and other characterizations revealed that the phenolic/amino lignins and tannins portions in CDs are susceptible to laccase transformation, resulting in graphitic structure damage and smaller-sized fragments. By using the 13C stable isotope labeling technique, we quantified the uptake and translocation of 13C-CDs by mung bean plants. 13C-CDs (10 mg L-1) accumulated in the root, stem, and leaf were estimated to be 291, 239, and 152 µg g-1 at day 5. We also evidenced that laccase treatment alters the particle size and surface chemistry of CDs, which could facilitate the uptake of CDs by plants and reduce their nanotoxicity to plants.

Seryl-tRNA Synthetase Shows a Noncanonical Activity of Upregulating Laccase Transcription in Trametes hirsuta AH28-2 Exposed to Copper Ion.

The function of Seryl-tRNA synthetase in fungi during gene transcription regulation beyond translation has not been reported. Here, we report a seryl-tRNA synthetase, ThserRS, which can negatively regulate laccase lacA transcription in Trametes hirsuta AH28-2 under exposure to copper ion. ThserRS was obtained through yeast one-hybrid screening using a bait sequence of lacA promoter (-502 to -372 bp). ThserRS decreased while lacA increased at the transcription level in T. hirsuta AH28-2 in the first 36 h upon CuSO4 induction. Then, ThserRS was upregulated, and lacA was downregulated. ThserRS overexpression in T. hirsuta AH28-2 resulted in a decrement in lacA transcription and LacA activity. By comparison, ThserRS silencing led to increased LacA transcripts and activity. A minimum of a 32-bp DNA fragment containing two putative xenobiotic response elements could interact with ThserRS, with a dissociation constant of 919.9 nM. ThserRS localized in the cell cytoplasm and nucleus in T. hirsuta AH28-2 and was heterologously expressed in yeast. ThserRS overexpression also enhanced mycelial growth and oxidative stress resistance. The transcriptional level of several intracellular antioxidative enzymes in T. hirsuta AH28-2 was upregulated. Our results demonstrate a noncanonical activity of SerRS that acts as a transcriptional regulation factor to upregulate laccase expression at an early stage after exposure to copper ions. IMPORTANCE Seryl-tRNA synthetase is well known for the attachment of serine to the corresponding cognate tRNA during protein translation. In contrast, its functions beyond translation in microorganisms are underexplored. We performed in vitro and cell experiments to show that the seryl-tRNA synthetase in fungi with no UNE-S domain at the carboxyl terminus can enter the nucleus, directly interact with the promoter of the laccase gene, and negatively regulate the fungal laccase transcription early upon copper ion induction. Our study deepens our understanding of the Seryl-tRNA synthetase noncanonical activities in microorganisms. It also demonstrates a new transcription factor for fungal laccase transcription.

Fungal Biotransformation of Hazardous Organic Compounds in Wood Waste.

A diverse spectrum of organisms, such as fungi, bacteria, and actinomycetes, can degrade and transform organic matter, including wood, into valuable nutrients. A sustainable economy has the goal of efficiently using waste as raw materials, and in this optic, it uses biological preparations more and more often, supporting the decomposition of lignocellulosic waste. With reference to wood wastes, which are produced in a substantial amount by the forest and wood industry, one of the possibilities to biodegrade such lignocellulosic material is the composting process. In particular, microbiological inoculum containing dedicated fungi can contribute to the biodegradation of wood waste, as well as the biotransformation of substances from the protection of wood, such as pentachlorophenol (PCP), lindane (hexachlorobenzene) and polycyclic aromatic hydrocarbons (PAHs). The purpose of this research was to produce a literature review in terms of the selection of decay fungi that could potentially be used in toxic biotransformation unions. The findings of the literature review highlighted how fungi such as Bjerkandera adusta, Phanerochaete chrysosporium, and Trametes versicolor might be ingredients of biological consortia that can be effectively applied in composting wood waste containing substances such as pentachlorophenol, lindane, and polycyclic aromatic hydrocarbons (PAHs).

Optimization of dye-contaminated wastewater treatment by fungal Mycelial-light expanded clay aggregate composite.

Dye-contaminated wastewaters from the printing batik industry are hazardous if discharged into the environment without any treatment. Finding an optimization and reusability assessment of a new fungal-material composite for dye-contaminated wastewater treatment is important for efficiency. The study purposes to optimize fungal mycelia Trametes hirsuta EDN 082 - light expanded clay aggregate (myco-LECA) composite for real priting batik dye wastewater treatment by using Response Surface Methodology with Central Composite Design (RSM-CCD). The factors included myco-LECA weight (2-6 g), wastewater volume (20-80 mL), and glucose concentration (0-10%) were applied for 144 h of incubation time. The result showed that the optimum condition was achieved at 5.1 g myco-LECA, at 20 mL wastewater, and at 9.1% glucose, respectively. In this condition, the decolorization values with an incubation time of 144 h were 90, 93, and 95%, at wavelengths 570, 620, and 670 nm, respectively. A reusability assessment was conducted for 19 cycles and the result showed that decolorization effectiveness was still above 96%. GCMS analysis showed the degradation of most compounds in the wastewater and the degradation products of the wastewater demonstrated detoxification against Vigna radiata and Artemia salina. The study suggests that myco-LECA composite has a good performance and therefore is a promising method for the treatment of printing batik wastewater.

Effective bioremediation of clarithromycin and diclofenac in wastewater by microbes and Arundo donax L.

Bioremediation of pharmaceuticals has gained large research efforts, but there is still a need to improve the performance of bioremediation systems by selecting effective organisms. In this study, we characterized the capability to remove clarithromycin (CLA) and diclofenac (DCF) by the bacterium Streptomyces rochei, and the fungi Phanerochaete chrysosporium and Trametes versicolor. The macrolide antibiotic CLA and the non-steroid anti-inflammatory DCF were selected because these are two of the most frequently detected drugs in water bodies. Growth and content of the PhCs and a DCF metabolite (MET) by the energy crop Arundo donax L. were also evaluated under hydroponic conditions. The removal rate (RR) by S. rochei increased from 24 to 40% at 10 and 100 µg CLA L-1, respectively, averaged over incubation times. At 144 h, the RR by P. chrysosporium was 84%, while by T. versicolor was 70 and 45% at 10 and 100 CLA µg L-1. The RR by S. rochei did not exceed 30% at 1 mg DCF L-1 and reached 60% at 10 mg DCF L-1, whereas approached 95% and 63% by P. chrysosporium and T. versicolor, respectively, at both doses. Root biomass and length of A. donax were strongly affected at 100 µg CLA L-1. CLA concentration in roots and shoots increased with the increase of the dose and translocation factor (TF) was about 1. DCF severely affected both shoot fresh weight and root length at the highest dose and concentration in roots and shoots increased with the increase of the dose. DCF concentrations were 16-19 times higher in roots than in shoots, and TF was about 0.1. MET was detected only in roots and its proportion over the parent compound decreased with the increase of the DCF dose. This study highlights the potential contribution of A. donax and the tested microbial inoculants for improving the effectiveness of bioremediation systems for CLA and DCF removal.

Arsenic(III)-induced oxidative defense and speciation changes in a wild Trametes versicolor strain.

Oxidative defense or arsenic(As) changes exhibited by Trametes versicolor in response to toxicity under As stress remain unclear. In this study, after internal transcribed spacer identification, a wild T. versicolor HN01 strain was cultivated under 40 and 80 mg/L of As III stress. The antioxidant contents by multifunctional microplate reader and the speciations of As by high performance liquid chromatography in conjunction with inductively coupled plasma mass spectrometry were examined to explore the detoxification mechanisms. The results demonstrated this strain could tolerate As concentration of 80 mg/L with a bio-enrichment coefficients of 11.25. Among the four antioxidants, the activities of catalase, superoxide dismutase, and glutathione in the As-stress group at 80 mg/L improved by 1.10, 1.09, and 20.47 times that of non-stress group, respectively. The speciation results indicated that AsV was the dominant species in the hyphae of T. versicolor regardless of no-stress or As-stress. The detoxification mechanisms of this strain were involved alleviating the toxicity by increasing the activities of antioxidants, especially glutathione, as well as by converting As III into As V and other less toxic As species. T. versicolor could be used as a bio-accumulator to deal with As exposure in contaminated environments based on its extraordinary As tolerance and accumulation capacities.

In-situ synchrotron imaging, experimental, and computational investigations on the efficiency of Trametes versicolor laccase on detoxification of P-Cresyl Sulfate (PCS) Protein Bound Uremic Toxin (PBUT).

Protein bound uremic toxins (PBUTs) are small substances binding to larger proteins, mostly human serum albumin (HSA), and are challenging to remove by hemodialysis (HD). Among different classes of PBUTs, p-cresyl sulfate (PCS) is the most widely used marker molecule and major toxin, as 95 % is bound to HSA. PCS has a pro-inflammatory effect and increases both the uremia symptom score and multiple pathophysiological activities. High-flux HD to clear PCS leads to serious loss of HSA, which results in a high mortality rate. The goal of the present study is to investigate the efficacy of PCS detoxification in serum of HD patients using a biocompatible laccase enzyme from Trametes versicolor. Molecular docking was used to gain an in-depth understanding of the interactions between PCS and the laccase to identify the functional group(s) responsible for ligand-protein receptor interactions. UV-Vis spectroscopy and gas chromatography-mass spectrometry (GC-MS) were used to assess the detoxification of PCS. GC-MS was used to identify the detoxification byproducts and their toxicity was assessed using docking commutations. In situ synchrotron radiation micro-computed tomography (SR-µCT) imaging available at the Canadian Light Source (CLS) was conducted to assess HSA binding with PCS before and after detoxification with laccase and undertake the corresponding quantitative analysis. GC-MS analyses confirmed the detoxification of PCS with laccase at a concentration of 500 mg/L. The potential pathway of PCS detoxification in the presence of the laccase was identified. Increasing laccase concentration led to the formation of m-cresol, as indicated by the corresponding absorption in the UV-Vis spectra and a sharp peak on the GC-MS spectra. Our analysis provides insight into the general features of PCS binding on Sudlow site II, as well as insights into PCS detoxification product interactions. The average affinity energy for detoxification products was lower than that of PCS. Even though some byproducts showed potential toxicity, the level was lower than for PCS based on toxicity indexes (e.g., LD50/LC50, carcinogenicity, neurotoxicity, mutagenicity). In addition, these small compounds can also be more easily removed by HD compared to PCS. SR-µCT quantitative analysis showed adhesion of the HSA to a significant reduced extent in the presence of the laccase enzyme in bottom sections of the polyarylethersulfone (PAES) clinical HD membrane tested. Overall, this study opens new frontiers for PCS detoxification.

Plasticizer phthalate esters degradation with a laccase from Trametes versicolor: effects of TEMPO used as a mediator and estrogenic activity removal.

Phthalate esters (PAEs) are toxic and persistent chemicals that are ubiquitous in the environment and have attracted worldwide attention due to their threats to the environment and human health. Dimethyl phthalate (DMP) is a relatively simple structure and one of the most observed PAEs in the environment. This study investigated the degradation of the DMP using Trametes versicolor laccase and its laccase-mediator systems. The degradation effect of laccase alone on DMP was poor, while the laccase-mediator systems can effectively enhance the degradation efficiency. Within 24 h, 45% of DMP (25 mg/L) was degraded in the presence of 0.8 U/mL laccase and 0.053 mM 2, 2, 6, 6-tetramethylpiperidine-1-oxyl (TEMPO). A certain concentration (1 mM) of metal ions Al3+, Cu2+ or Ca2+ can positively promote DMP degradation with the laccase-TEMPO system. Moreover, the structure of PAEs also had a great influence on the degradation efficiency. Higher degradation efficiencies were observed when incubating PAEs with short alkyl side chains by the laccase-TEMPO system compared to that with long alkyl side chains. Additionally, the branched-chain PAEs had a better degradation effect than the straight-chain. The estrogenic activity of the DMP solution after reaction was much smaller than that of the original solution. Finally, transformation products ortho-hydroxylated DMP and phthalic acid were identified by GC-MS and the possible degradation pathway was proposed. This study verifies the feasibility of the laccase-TEMPO system to degrade PAEs and provides a reference for exploring more potential value of laccase.

Trametes hirsuta as an Attractive Biocatalyst for the Preparative Scale Biotransformation of Isosafrole into Piperonal.

Piperonal is a compound of key industrial importance due to its attractive olfactory and biological properties. It has been shown that among the fifty-six various fungal strains tested, the ability to cleave the toxic isosafrole into piperonal through alkene cleavage is mainly found in strains of the genus Trametes. Further studies involving strains isolated directly from different environments (decaying wood, fungal fruiting bodies, and healthy plant tissues) allowed the selection of two Trametes strains, T. hirsuta Th2_2 and T. hirsuta d28, as the most effective biocatalysts for the oxidation of isosafrole. The preparative scale of biotransformation with these strains provided 124 mg (conv. 82%, isolated yield 62%) and 101 mg (conv. 69%, isolated yield 50.5%) of piperonal, respectively. Due to the toxic impact of isosafrole on cells, preparative scale processes with Trametes strains have not yet been successfully performed and described in the literature.

Natural durability of timber species exposed to xylophagous fungi in southern Durango, Mexico.

Introduction: Wood is a natural resource used for construction and the manufacture of many products. This material is exposed to damage due to biotic and abiotic factors. An important biotic factor is wood-degrading fungi that generate large economic losses. The objectives of this study were to determine the effect of xylophagous fungi (Coniophora puteana and Trametes versicolor) on the natural durability of six timber species in southern Durango, Mexico, and to establish differences between fungal effects on each tree species. Materials and Methods: Samples of Pinus durangensis, P. cooperi, P. strobiformis, Juniperus deppeana, Quercus sideroxyla, and Alnus acuminata were exposed to fungi for 4 months under laboratory conditions according to European Standard EN350-1. Samples of Fagus sylvatica were used as control. Durability was determined as the percentage of wood mass loss for each species. Welch ANOVA tests were performed to establish differences among tree species. Welch t-tests were used to prove loss mass differences between fungi for each tree species. Results: The most resistant species to C. puteana were P. durangensis, J. deppeana, P. cooperi and P. strobiformis, showing mean mass losses lower than 8.08%. The most resistant species to T. versicolor were J. deppeana, P. strobiformis and P. durangensis (mean mass losses lower than 7.39%). Pinus strobiformis and Q. sideroxyla were more susceptible to C. puteana effect; in contrast, P. durangensis and P. cooperi showed more damage due to T. versicolor degradation. Conclusions: Woods of P. durangensis, P. cooperi, P. strobiformis and Juniperus deppeana are well adapted to infection by these xylophagous fungi and are therefore highly recommended for commercial use in southern Durango, Mexico.