Ligninolytic Fungi Research Articles

Inoculation of cellulolytic and ligninolytic microorganisms accelerates decomposition of high C/N and cellulose rich sugarcane straw in tropical sandy soils

Due to the limited functional potential of the microbial decomposer community in tropical sandy soils, a significant proportion of organic inputs with a high C/N ratio and cellulose (CL) content may remain undecomposed. Moreover, high C/N ratio organic input led to N immobilization and suppressed succeeding crop yield. Inoculation of competent microbial decomposers to such soils could constitute a promising approach to overcome this problem, with beneficial effects on soil organic carbon (SOC) accumulation. Therefore, the objectives were (i) to assess the ability of selected cellulolytic and ligninolytic microbial inoculants to promote the decomposition of high C/N ratio and high cellulose inputs in the initial stages after application, using soil enzyme activity measurements, and (ii) to verify the decomposition efficiency of microbial inocula to enhance short-term soil organic carbon (SOC) quantity and quality, using mid-infrared diffuse reflectance Fourier transform spectroscopy (midDRIFTS)-based functional SOC group analysis, integrated with assayed soil enzyme activities. The experiments consisted of 4 treatments: 1) Control (C): no application of organic inputs; 2) Mulch (M): sugarcane straw mulched at a rate of 6.25 tons ha−1; 3) Incorporation (I): sugarcane straw incorporated to soil at a rate of 6.25 tons ha−1; and 4) Incorporation (treatment 3) + inoculation of an artificial microbial consortium (I + MC). Two experiments were conducted i.e. experiment I (field-based micro-plot and litter bag study (32 weeks)) using a randomized complete block design (RCBD) and experiment II (lab-based incubation study (84 days)) using a completely randomized block design (CRD). Sandy soils derived from a farmer's field located in the Khon Kean province (Northeast Thailand) were used. MC was composed of cellulolytic and ligninolytic bacteria (2.2 × 108 CFU g−1 soil) and fungi (1.9 × 106 CFU g−1 soil) with an application rate of 0.1 g kg−1 sugarcane straw. Our results indicated that treatment I + MC led to the highest dry weight loss of sugarcane straw (73%), highest cellulolytic and ligninolytic enzyme activities (β-glucosidase, cellulase, peroxidase, and phenoloxidase), and short-term SOC accumulation. I + MC also showed increased peroxidase and phenoloxidase activities in the early stages of decomposition. Integration of midDRIFTS and enzyme activity analyses demonstrated that in the initial stages of decomposition cellulolytic and ligninolytic enzyme activities enhanced labile SOC components, while in the later stage, cellulolytic and ligninolytic activities enhanced both labile and stable SOC components. In conclusion, farmers may benefit from this approach, but field validation would be needed prior envisioned large-scale application, including the development of formulation and field application processes, evaluated against environmental and economic indicators.

Preliminary Evaluation of Three Species of Ligninolytic Fungi for Their Possible Incorporation in Vertical Flow Treatment Wetlands for the Treatment of Tequila Vinasse

Preliminary Evaluation of Three Species of Ligninolytic Fungi for Their Possible Incorporation in Vertical Flow Treatment Wetlands for the Treatment of Tequila Vinasse

Microbial proportion and heterotroph CO2 flux from drainage peatland under oil palm plantation

The difference in soil layer can affect heterotroph respiration that means CO2 fluxes from microbial decomposition in peatlands. Oil palm plants release root exudates transported to other places, i.e., shrub, by water movement, which can stimulate microbial activity. This study was conducted to learn the effects of differences of the soil layer and distance from the trunk in drainage peatland under oil palm plantation on total bacteria, fungi, cellulolytic bacteria, ligninolytic fungi, and heterotroph fluxes CO2, then compared to a shrub. Heterotroph respiration decreased with soil layer depth, where at the layer 0-20 cm released amount of CO2 as much 6.07 + 1.76, at 20-40 cm was 5.18 + 0.50, and at 40-60 cm 5.27 + 1.20 mg CO2 100 g-1 day-1, and tended higher than in shrub where a layer of 0-20 cm released 5.51 + 1.69, then decrease at 20-40 cm to 4.83 + 1.38, and at 40-60 cm 4.30 + 1.08 mg CO2 100 g-1 day-1. Total bacteria (107 CFU g-1) and fungi (105 CFU g-1) were higher than total cellulolytic bacteria (103 CFU g-1) and ligninolytic fungi (102 CFU g-1) in both under oil palm plantation and shrub. Organic acids affected the abundance of total bacteria and fungi but did not affect cellulolytic bacteria and ligninolytic fungi on both sites, as shown by a lower population and low cellulose and laccase enzymes. These findings showed that heterotroph CO2 flux tended higher in oil palm plantations and lignocellulolytic microbes are not the only source of heterotroph respiration.

APPLICATION OF BROMELAIN LITTER SOLID COMPOST INDUCED BY LIGNINOLITIK Trichoderma sp. FUNGUS TOWARDS NUMBER OF LEAVES AND CHLOROPHYL CONTENT CHILI PLANTS (Capsicum annuum L.)

Piles of uncontrolled pineapple peel waste have a negative impact that will affect various aspects of life, either directly or indirectly. Therefore, pineapple peel waste that can no longer be processed can be used for making compost. The taste of pineapple can be degraded biologically with the help of enzymes that can be produced by microorganisms. One of the microorganisms that can support the decomposition process is a group of fungi. In this study, the fungus Trichoderma sp. (Bioggp 5) is a ligninolytic fungus. Trichoderma sp. is a saprophytic soil microorganism that attacks natural pathogenic fungi and is beneficial to plants. The purpose of this study was to determine the effect of solid bromelain compost inoculum of ligninolytic fungi (Trichoderma sp.) on leaf number and chlorophyll content of chili plants (Capsicum annum L.) and the best dose of compost that could be used. This study used a completely randomized design (CRD) with 7 treatments, namely T0 (control), T1 (1.4% pure bromelain), T2 (1.7% pure bromelain), T3 (2% pure bromelain), T4 (1, 4% bromelain + leaf litter), T5 (1.7% bromelain + leaf litter), T6 (2% bromelain + leaf litter). The parameters used were the number of leaves and chlorophyll content. And the results obtained from this study were the T3 dose (2% pure bromelain) was the best dose for the number of leaves, while the T2 dose (1.7% pure bromelain) was the best dose for chlorophyll content.

VEGETATIVE GROWTH OF TOMATO (Lycopersicum esculentum Mill.) INFLUENCED BY AERATED COMPOST TEA (ACT) FROM BROMELAIN LITTER INDUCED BY LIGNINOLITIC Trichoderma sp.

The pineapple waste increased by the rise of production in pineapple, one of increasing pineapple waste is pineapple pulp (bromelain litter). The bromelain litter will be disadvantage for the environment, this matter could be solved by converting bromelain litter into compost. The composting process in this study used ligninolytic fungus (Trichoderma sp.). Composting technology which currently has rapidly developed is Aerated Compost Tea (ACT) or a derivate product of compost. The use of this study was to ensure the best incubation period of ACT bromelain litter which induced by Trichoderma sp. fungus on the growth of tomato (L. esculentum Mill.). The study was conducted using a completely randomized design (CRD) with 7 treatments and 3 replications, namely: P0= control (without ACT), P1= ACT bromelain 24 hours, P2= ACT bromelain 48 hours, P3= ACT bromelain 72 hours, P4= ACT bromelain and leaf litter 24 hours, P5= ACT bromelain and leaf litter 48 hours, and P6= ACT bromelain and leaf litter 72 hours. The variables observed were number of leaves and plant chlorophyll content. The data obtained were analyzed with ANOVA at the level of 5 % and tested for the Least Significant Difference (LSD) at the level of 5 %. The results of this study showed that ACT was induced by Trichoderma sp. fungus which effective for the vegetative growth of tomato (L. esculentum Mill.) is ACT bromelain litter with incubation period up to 72 hours (P3).

MANUFACTURE OF LIGNINOLYTIC FUNGI INOCULUM Geotrichum sp. WITH SORGUM (Sorghum bicolor) MEDIA AND ITS EFFECT ON THE QUALITY OF BAMBOO LEAF COMPOST (Bambusa sp.)

Bamboo is a type of plant that grows in Indonesia. So far, people only use the stems and throw away the leaves. As a result, these abundant bamboo leaves become waste. Bamboo leaf waste contains lignin content of 19.8-26.6%, and becomes compost in the long term. The process of composting bamboo leaf litter can be accelerated using an activator such as the inoculum fungi Geotrichum sp. which is ligninolytic so that it can break down lignin complex compounds contained in bamboo leaf waste into simpler compounds. Sorghum contains about 6.5-7.9% fiber. The high fiber content in sorghum seeds can be used as a growth medium for fungal inoculum. The purpose of this study was to determine the effect of sorghum as an inoculum medium for Geotrichum sp. and the effect of inoculum on compost quality. This research was carried out in August - December 2019 at the Microbiology Laboratory of the Biology Department, Faculty of Mathematics and Natural Sciences, Unila. This study used a completely randomized design (CRD) method with 4 treatments, namely Control (Bamboo leaf litter), P1 (Bamboo leaf litter + 1% inoculum), P2 (Bamboo leaf litter + 1.5 % inoculum) and P3 (Bamboo leaf litter). + 2% inoculum) each treatment was repeated 3 times. The variables observed were the number of spores and spore viability using the Colony Forming Unit (CFU) calculation on inoculum and compost. Analysis of the content of C, N, P, and C/N ratio was carried out to determine the quality of the compost. Based on the research results, sorghum can be used as a growth medium for the ligninolytic fungi inoculum Geotrichum sp. with spore viability of 74.18% and the addition of 1.5% inoculum (P2) gave the best results on the quality of bamboo leaf compost (Bambusa sp.)

A novel basydiomycete isolated from mangrove swamps in the Colombian Caribbean shows promise in dye bioremediation

Ligninolytic fungi derived from coastal and marine environments, particularly mangrove swamps, are considered potential sources of novel enzymes with unique properties (thermostability, high-redox potential, salt and pH tolerance) not found in terrestrial strains, which are very attractive for the development of effective solutions for the elimination of contamination caused by the textile industry. In this study, the isolation and ligninolytic screening of 73 fungal strains derived from mangrove swamps were achieved. Ten strains showed ligninolytic potential, among which, the basidiomycete identified as INV BAS1 (Cyphellaceae family) exhibited outstanding laccase activity (11873.8 ± 329.0 UL−1). The laccase production was enhanced (5-fold) by optimizing the medium components concentration using a statistical design that combined the one factor at a time method and a central composite rotational design (CCRD), under Response Surface Methodology (RSM). Decolorization of the recalcitrant textile dye Remazol Briliant Blue R (RBBR) was carried out through fermentation and the use of enzyme extracts, reaching decolorization percentages of up to 95.64 ± 1.28 %, under alkaline and high salinity conditions. The laccase activity in the bulk extracts was the major responsible for the RBBR degradation according to gel zymography, UV-Vis and ATR-FTIR spectroscopy. These results contribute to the knowledge of fungal diversity in tropical mangroves and confirm their potential for the development of new bioremediation strategies in high-salt and alkaline effluents generated by the textile industry.

Biodegradation and detoxification of phenanthrene in in vitro and in vivo conditions by a newly isolated ligninolytic fungus Coriolopsis byrsina strain APC5 and characterization of their metabolites for environmental safety.

Polycyclic aromatic hydrocarbons (PAHs) are recalcitrant organic pollutants generated from agricultural, industrial, and municipal sources, and their strong carcinogenic and teratogenic properties pose a harmful threat to human beings. The present study deals with the bioremediation of phenanthrene by a ligninolytic fungus, Coriolopsis byrsina (Mont.) Ryvarden strain APC5 (GenBank; KY418163.1), isolated from the fruiting body of decayed wood surface. During the experiment, Coriolopsis byrsina strain APC5 was found as a promising organism for the degradation and detoxification of phenanthrene (PHE) in in vitro and in vivo conditions. Further, HPLC analysis showed that the C. byrsina strain degraded 99.90% of 20 mg/L PHE in in vitro condition, whereas 77.48% degradation of 50 mg/L PHE was reported in in vivo condition. The maximum degradation of PHE was noted 25 °C temperature under shaking flask conditions at pH 6.0. Further, GC-MS analysis of fungal treated samples showed detection of 9,10-Dihydroxy phenanthrene, 2,2-Diphenic acid, phthalic acid, 4-heptyloxy phenol, benzene octyl, and acetic acid anhydride as the metabolic products of degraded PHE. Furthermore, the phytotoxicity evaluation of degraded PHE was observed through the seed germination method using Vigna radiata and Cicer arietinum seeds. The phytotoxicity results showed that the seed germination index and vegetative growth parameters of tested plants were increased in the degraded PHE soil. As results, C. byrsina strain APC5 was found to be a potential and promising organism to degrade and detoxify PHE without showing any adverse effect of their metabolites.

Biodegradation Pathway of Polycyclic Aromatic Hydrocarbons by Ligninolytic Fungus Podoscypha elegans Strain FTG4 and Phytotoxicity Evaluation of their Metabolites

Biodegradation Pathway of Polycyclic Aromatic Hydrocarbons by Ligninolytic Fungus Podoscypha elegans Strain FTG4 and Phytotoxicity Evaluation of their Metabolites

Screening of ligninolytic fungi for bioremediation of dyes

Water pollution is a growing concern worldwide. One of the main causes of water pollution includes the textile industry which produces a large amount of wastewater every day. This wastewater is known to contain dyes that are recalcitrant and hard to treat. In order to solve this problem, bioremediation using ligninolytic fungi is commonly used for the ligninolytic enzymes which are able to break down the dyes. In this study, samples were collected from decaying woods and soils in the vicinity of UiTM Puncak Alam forests. A total of 20 fungal isolates were tested for ligninolytic enzyme production. Out of the 20 isolates, 13 were found to produce lignin peroxidase and manganese peroxidase, but only one produced laccase. The isolate that produced all three enzymes was used for DNA isolation and identified using amplification of the ITS region by PCR. The isolate was identified as Trichoderma asperellum, a soft rot fungal species which is renowned for its role in bioremediation as a biosorbent.

Lignin-Degrading Microorganisms from Organic Soils

The most prevalent aromatic polymer in nature is lignin, produced by higher plants and thought to make up 30-35 percent of the non-fossil organic carbon on the planet. Lignin hydrolyzing enzymes such as lignin peroxidase, laccase, manganese peroxidase, and others produce a variety of aromatic monomers, including ferulic and vanillic acids. However, very little research has been done on the role of microbes in lignin degradation. In the present work, we have isolated 25 ligninolytic bacteria and 25 ligninolytic fungi from organic soils of Koppal, Raichur districts of Karnataka. The bacterial isolates were identified as Pseudomonas putida, Bacillus subtilis, based on biochemical tests, and fungi were identified as Aspergillus niger, Trichoderma viridae, Phanerochaete chrysosporium and Pleurotus ostreatus based on morphological characters. The ligninolytic activity of bacterial isolates was high when compared to fungal isolates. All the isolates produced detectable amounts of lignin peroxidase, manganese peroxidase, and laccase under in vitro conditions. In dye decolorization test, fungal isolates KGST-1, KGST-2, and KKSP could decolorize Ramazol Brilliant Blue R and Congo red.

Degradation Products of Polychlorinated Biphenyls and Their In Vitro Transformation by Ligninolytic Fungi.

Metabolites of polychlorinated biphenyls (PCBs)—hydroxylated PCBs (OH-PCBs), chlorobenzyl alcohols (CB-OHs), and chlorobenzaldehydes (CB-CHOs)—were incubated in vitro with the extracellular liquid of Pleurotus ostreatus, which contains mainly laccase and low manganese-dependent peroxidase (MnP) activity. The enzymes were able to decrease the amount of most of the tested OH-PCBs by > 80% within 1 h; the removal of more recalcitrant OH-PCBs was greatly enhanced by the addition of the laccase mediator syringaldehyde. Conversely, glutathione substantially hindered the reaction, suggesting that it acted as a laccase inhibitor. Hydroxylated dibenzofuran and chlorobenzoic acid were identified as transformation products of OH-PCBs. The extracellular enzymes also oxidized the CB-OHs to the corresponding CB-CHOs on the order of hours to days; however, the mediated and nonmediated setups exhibited only slight differences, and the participating enzymes could not be determined. When CB-CHOs were used as the substrates, only partial transformation was observed. In an additional experiment, the extracellular liquid of Irpex lacteus, which contains predominantly MnP, was able to efficiently transform CB-CHOs with the aid of glutathione; mono- and di-chloroacetophenones were detected as transformation products. These results demonstrate that extracellular enzymes of ligninolytic fungi can act on a wide range of PCB metabolites, emphasizing their potential for bioremediation.

Diversity and Geographic Distribution of Ligninolytic Fungi Associated With Castanopsis sieboldii Leaf Litter in Japan.

The diversity and geographic pattern of ligninolytic fungi were investigated within the distribution range of an evergreen tree, Castanopsis sieboldii (Fagaceae), in Japan. Fungal isolates obtained from 18 sites in subtropical and temperate regions in Japan were classified into 50 operational taxonomic units in Ascomycota and Basidiomycota according to the base sequence of the rDNA internal transcribed spacer region. Ordination by nonmetric multidimensional scaling showed the separation of fungal compositions between the study sites which was significantly related to the latitude, longitude, and mean annual temperature (MAT) of the study sites. We applied variation partitioning to separate the magnitude of the climatic, spatial, and leaf property factors and found the roles of MAT and spatial factors in structuring fungal assemblages, suggesting the importance of both niche processes and such non-niche processes as priority effect and dispersal limitation. The bleached area on leaf litter was greater at sites with higher MAT and precipitation located at lower latitudes and at sites where some major ligninolytic fungi occurred at greater relative frequencies, indicating that not only the climatic conditions but also the biogeographic patterns of distribution of ligninolytic fungi influence the decomposition of lignin in leaf litter.

Biodegradation potential of indigenous litter dwelling ligninolytic fungi on agricultural wastes

BackgroundThe present study was focused to study the efficiency of two indigenous litter dwelling ligninolytic fungi (such as Mucor circinelloides GL1 and Fusarium verticillioides GL5) in degrading the agricultural wastes (areca husk, coffee husk and paddy straw) through solid-state fermentation.ResultsAfter fermentation process, the lignocellulosic residues left over were evaluated for their physico-chemical studies and degradation pattern of cell wall constituents along with the activity of enzymes. In each substrate, the initial pH was found to change from near-neutral to acidic pH after fungal decomposition. Significantly increased loss of total organic matter and organic carbon content was observed in each substrate decomposed by the fungal strains selected. The total nitrogen, crude protein, total phosphorus and total potassium contents of the fungal decomposed substrates were significantly increased with the progress of time. The study indicated that the degradation patterns of lignin and holocellulose were more effective from 20 to 120 days after fungal inoculation with respect to their loss between the different harvesting intervals. During decomposition process, both the strains produced the ligninolytic enzymes [laccase, manganese peroxidase (MnP) and lignin peroxidase (LiP)] and carboxymethyl cellulase (CMCase) on each substrate with their remarkably varied activities with respect to different harvesting times.ConclusionsIn concern with the present environmental problems, the present study suggested that these potential ligninolytic fungi can be utilized successfully for the management of agricultural wastes and reuse of their residues in the forest soil conservation system to eliminate the harmful effects of the crop residue burning.

Characterization of 2,3,7,8-tetrachlorodibenzo-p-dioxin biodegradation by extracellular lignin-modifying enzymes from ligninolytic fungus

Ligninolytic fungi secrete extracellular lignin-modifying enzymes (LME) that degrade plant polymers for fungal nutrition but that are, because of their broad substrate specificity, also applicable for the degradation of many hazardous pollutants. Laccase is one of the most well characterized LME and is involved in the removal and degradation of recalcitrant aromatic compounds with or without the assistance of laccase-mediators. The Ligninolytic fungus Rigidoporus sp. FMD21 can degrade 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) with a half-life of 6.2 days. Using Rigidoporus sp. FMD21 crude extracellular enzyme extract (ExE) that mainly consisted of laccase, 77.4% of 2,3,7,8-TCDD was degraded within 36 days. The degradation rate did not depend on the 2,3,7,8-TCDD concentration in the tested range between 0.005 and 0.5 pgTEQ/μL. 2,3,7,8-TCDD was analysed by DR-CALUX® bioassay and the degradation was confirmed by GC-HRMS. In this study, we found evidence for cleavage of the diaryl ether bond in the 2,3,7,8-TCDD molecule and here we propose a new degradation mechanism in which 3,4-dichlorophenol is the main metabolite of 2,3,7,8-TCDD degradation by FMD21’s ExE. Six laccase-mediators were tested. Three of them 1-hydroxybenzotriazole (HBT), syringaldehyde (Syr) and violuric acid (Vio) showed an equipotent added effect on 2,3,7,8-TCDD degradation by ExE, however only in case of Vio a level of significance was reached. The others showed no effect or negatively impacted degradation. In conclusion, we have shown that Rigidoporus sp. FMD21 produces extracellular enzymes, mainly laccases that apparently are able to degrade the highly recalcitrant and most toxic 2,3,7,8-congener of TCDD via diaryl bond cleavage into 3,4-dichlorophenol.

High dye removal capacity of Peniophora laxitexta immobilized in a combined support based on polyurethane foam and lignocellulosic substrates

ABSTRACT Dye removal from effluents is a major problem for most textile industries. At present, wastewater treatments are currently based on physico-chemical methods which are expensive, energy inefficient and of limited versatility. The aim of this work was to find a low-cost and efficient method for dye removal. To do this, we designed a combined system based on the immobilization of the ligninolytic white-rot fungus Peniophora laxitexta (BAFC 4687) on mixed supports consisting of two polyurethane foam discs and a middle layer of diverse lignocellulosic substrates: soybean hulls, wheat straw or cellulose spent casings. As a corticioid fungus, P. laxitexta was able to completely colonize the supports developing a compact and tight structure that maintained the integrity of the system after several dye removal cycles. The immobilized fungus removed between 30% and 50% of the azoic dye Xylidine and more than 50% of the anthraquinonic dye RBBR in three successive cycles, and near 90% of the triphenylmethane Malachite Green in 10 repeated cycles without any loss of efficiency. Our analysis showed that the removal of the dyes was due to the combined effect of adsorption to the supports and enzymatic decolorization by soluble laccases and enzymes associated with the mycelium. Additionally, we showed that the presence of Malachite Green induced the expression of a new laccase isoform with high decolorization capacity. Based on these results, we propose that this inoculated laminar biocarrier could be effectively used for dye removal in textile wastewater.

Fungal bioremediation of diuron-contaminated waters: Evaluation of its degradation and the effect of amendable factors on its removal in a trickle-bed reactor under non-sterile conditions

The occurrence of the extensively used herbicide diuron in the environment poses a severe threat to the ecosystem and human health. Four different ligninolytic fungi were studied as biodegradation candidates for the removal of diuron. Among them, T. versicolor was the most effective species, degrading rapidly not only diuron (83%) but also the major metabolite 3,4-dichloroaniline (100%), after 7-day incubation. During diuron degradation, five transformation products (TPs) were found to be formed and the structures for three of them are tentatively proposed. According to the identified TPs, a hydroxylated intermediate 3-(3,4-dichlorophenyl)-1-hydroxymethyl-1-methylurea (DCPHMU) was further metabolized into the N-dealkylated compounds 3-(3,4-dichlorophenyl)-1-methylurea (DCPMU) and 3,4-dichlorophenylurea (DCPU). The discovery of DCPHMU suggests a relevant role of hydroxylation for subsequent N-demethylation, helping to better understand the main reaction mechanisms of diuron detoxification. Experiments also evidenced that degradation reactions may occur intracellularly and be catalyzed by the cytochrome P450 system. A response surface method, established by central composite design, assisted in evaluating the effect of operational variables in a trickle-bed bioreactor immobilized with T. versicolor on diuron removal. The best performance was obtained at low recycling ratios and influent flow rates. Furthermore, results indicate that the contact time between the contaminant and immobilized fungi plays a crucial role in diuron removal. This study represents a pioneering step forward amid techniques for bioremediation of pesticides-contaminated waters using fungal reactors at a real scale.

Crosslinked Enzyme Aggregates (CLEAs) of Laccases from Pleurotus citrinopileatus Induced in Olive Oil Mill Wastewater (OOMW).

The enzymatic factory of ligninolytic fungi has proven to be a powerful tool in applications regarding the degradation of various types of pollutants. The degradative potential of fungi is mainly due to the production of different types of oxidases, of which laccases is one of the most prominent enzymatic activities. In the present work, crude laccases from the supernatant of Pleurotus citrinopileatus cultures grown in olive oil mill wastewater (OOMW) were immobilized in crosslinked enzyme aggregates (CLEAs), aiming at the development of biocatalysts suitable for the enzymatic treatment of OOMW. The preparation of laccase CLEAs was optimized, resulting in a maximum of 72% residual activity. The resulting CLEAs were shown to be more stable in the presence of solvents and at elevated temperatures compared to the soluble laccase preparation. The removal of the phenolic component of OOMW catalyzed by laccase-CLEAs exceeded 35%, while they were found to retain their activity for at least three cycles of repetitive use. The described CLEAs can be applied for the pretreatment of OOMW, prior to its use for valorization processes, and thus, facilitate its complete biodegradation towards a consolidated process in the context of circular economy.

Biodegradability of Dental Care Antimicrobial Agents Chlorhexidine and Octenidine by Ligninolytic Fungi.

Chlorhexidine (CHX) and octenidine (OCT), antimicrobial compounds used in oral care products (toothpastes and mouthwashes), were recently revealed to interfere with human sex hormone receptor pathways. Experiments employing model organisms—white-rot fungi Irpex lacteus and Pleurotus ostreatus—were carried out in order to investigate the biodegradability of these endocrine-disrupting compounds and the capability of the fungi and their extracellular enzyme apparatuses to biodegrade CHX and OCT. Up to 70% ± 6% of CHX was eliminated in comparison with a heat-killed control after 21 days of in vivo incubation. An additional in vitro experiment confirmed manganese-dependent peroxidase and laccase are partially responsible for the removal of CHX. Up to 48% ± 7% of OCT was removed in the same in vivo experiment, but the strong sorption of OCT on fungal biomass prevented a clear evaluation of the involvement of the fungi or extracellular enzymes. On the other hand, metabolites indicating the enzymatic transformation of both CHX and OCT were detected and their chemical structures were proposed by means of liquid chromatography–mass spectrometry. Complete biodegradation by the ligninolytic fungi was not achieved for any of the studied analytes, which emphasizes their recalcitrant character with low possibility to be removed from the environment.

Evaluation of genotoxicity in industrial waste waters

This article presents the results of a research dealing with the detection of mutagenic activity of two samples used in the textile industry, Methylene Blue synthetic dye and Inotex real dye bath before, during and at the end of the biodegradation process by means of ligninolytic fungus Irpex lacteus. There is evidence that Methylene Blue synthetic dye was detected as an indirect mutagen prior to the biodegradation process. However, the biodegradation intermediate product was evaluated as a direct mutagen and the final product of biodegradation no longer induced any mutagenic activity. Inotex dye bath samples were assessed as non-mutagenic.