Degradation of lignite model compounds by the action of white rot fungi

Three compounds modeled on the lignite structure were chosen for experimental degradation by different fungi strains. Culture conditions and extracellular enzyme activities were optimized. The growth curves of the strains were determined to study mycelium dry weight and protein content changes. Gas chromatography and infrared spectroscopy were used to detect changes of functional groups before and after the action of the fungi on the model compounds. Possible decomposition products and degrada-tion mechanisms were proposed. The research findings show that C. Versicolor and Golden Mushroom can grow in presence of the model compounds. The optimum culture conditions were a pH of 6.0, a carbon-nitrogen ratio of five and a Tween-80 concentration of 0.1%. Newly produced substances were found by gas chromatography. Infrared analysis showed that the model compounds degraded under the action of the microorganisms.

Decolorization of reactive brilliant red K-2BP by white rot fungus under sterile and non-sterile conditions

Almost all the studies both domestic and international using white rot fungus for dye wastewater treatment are performed under sterile conditions. However, it is obviously unpractical that wastewater with dyes is treated under sterile conditions. A feasible study was made for using white rot fungus Phanerochaete chrysosporium to degrade reactive brilliant red K-2BP dye under non-sterile conditions. The results showed that there was no decolorizing effect under non-sterile condition if white rot fungus was incubated under non-sterile condition, and the decolorization was always near to 0% during decolorizing test for 3 d; in the meantime, a lot of yeast funguses were found in liquid medium when white rot fungus was incubated under non-sterile conditions; however, if white rot fungus was incubated under sterile condition firstly, its decolorization was above 90% under non-sterile condition, which was similar to that of sterile condition. So we point out that the treating process for wastewater with dyes should be divided into two stages. The first stage is that white rot fungus should be incubated under sterile conditions, and the second stage is that reactive brilliant red K-2BP is decolorized under non-sterile conditions. The method not only save the operation cost which decolorizing reactive brilliant red K-2BP under sterile condition, but also provide the feasibility for using white rot fungus to degrade wastewater with dyes under non-sterile conditions.

Experimental Study on Decolorization and Degradation of Reactive Brilliant Red X-3B in a White Rot Fungal Biofilm Reactor

Experimental results of an azo dye(reactive brilliant red X 3B, RBR X 3B) decolorization and degradation in a white rot fungal biofilm reactor were introduced and discussed. The fungal biofilm reactor is highly potential for dye decolorization and degradation with the highest decoloring rate of 95% within 96 hours reaction time at initial pH 4.5 under high nitrogen level (HN) (24 mmol/L ammonium tartrate) condition. Experimental conditions, such as nutrient nitrogen levels in reaction mixture and initial pH, significantly affected dye decolorization and degradation. Effluents from this biofilm reactor can be well treated to meet the discharging requirements by use of chemical flocculation.RBR X 3B was first absorbed onto fungal biomass and then degraded gradually. The SH 13 fungus monopolized the biofilm throughout the experiments, though the reactor was exposed to open air for 4 months.

Releasing nitrogen from ammoniated lignin by white rot fungus cometabolizes environmental pollutants

The nitrogen modified lignocelluloses(NML) produced under oxic ammoniation was metabolized by white rot fungus, NH + 4 N was released, NO - 3 N concentration was decreased and total nitrogen loss was blocked within incubation period. During releasing nitrogen from the metabolism of NML, white rot fungus cometabolized recalcitrant environmental pollutants and showed higher degradation capability. Results indicated that this NML complex colonized by white rot fungus might be effective with economic feasibility when they are applied into the vast field ecosystem, it might stabilize NH + 4 nitrogen flux and bioremediate the polluted environmental sites.

Effects of laccase incubated from white rot fungi on the mechanical properties of fiberboard

White rot fungi were optimized to cultivate highly active laccase. The characteristics of laccase incubated by continuous culture were compared with those of direct culture. The enzyme activity of laccase incubated by continuous culture technology reached a higher value on the fifth day of the growth. The optimization incubation time of high activity laccase was the eleventh day. A large amount of highly active laccase can be obtained in a relatively short time by continuous culture to replace traditional laccase. After laccase treatment, the lignin composition of wood fibers were oxidation-catalyzed by laccase. The number of chemical-bonding points between the wood fibers was increased. The wood fibers treated by laccase were fabricated into boards and their mechanical properties improved with the laccase-incubation times. Compared with the fiberboards made from fibers that were pre-treated by laccase of incubation 5 days, the static bending strength of those that were pre-treated by laccase of incubation 11 days was increased by 18.95%, the elastic modulus was increased by 35.49%, and the internal bond strength was increased by 44.11%.

BIO-DEINKING OF ONP AND ITS EFFLUENT TREATMENT BY WHITE ROT FUNGUS

Deinking of secondary fiber of ONP and effluent treatment with white rot fungus were studied in this paper. Results showed that white rot fungus exerted significant effect on deinking of ONP and CODcr decrease and degradation of pollutants of deinking effluent .

Biodegradation and Sugar Release from Canola Plant Biomass by Selected White Rot Fungi

Canola crop is rich in plant biomass. It is considered a major cash crop in North America and a potential source for biofuel. We evaluated six strains of white rot basidiomycetes under solid state fermentation (SSF) for their potentials to secrete oxidative and hydrolytic enzymes to biodegrade canola plant biomass (CPB), and release sugars. Fuscoporia gilva and Pleurotus tuberregium produced high amount of laccase (440.86 U/L and 480.63 U/L at day 7), as well as carboxylmethylcellulase (CMCase) (4.78 U/mL at day 21 and 3.13 U/mL at day 14) and xylanase (4.48 U/mL and 7.8 U/mL at day 21), respectively. Bjerkandera adusta showed high amount of MnP (50.4 U/L) and peroxidase (64.5 U/L), relative to the other strains. Loss of organic matter peaked after 21 days of incubation in all the tested strains;however, the best result (34.0%) was shown in P. tuberregium. The highest lignin loss was observed in Coriolopsis caperata strains. Among the sugar polymers, hemicellulose was highly degraded by P. tuberregium and P. pulmonarius (4.1% - 4.6%), while cellulose (3.3% - 4.3%) was mainly degraded by F. gilva and B. adusta. Glucose was the dominant sugar released by all the fungi tested, with the highest concentration of 1.25 mg/mL produced by B. adusta at day 14 of incubation. Results indicate that selected white rot fungi can achieve significant delignification of CPB within 14 days of solid state fermentation. Their importance in low cost pretreatment of lignocellulosic biomass prior to conversion into biofuels and bio-products of economic importance is discussed.

BIOCHEMICAL PULPING OF REED PRETREATED BY WHITE ROT FUNGI

The Soda-AQ pulps were made from reed pretreated by white rot fungi Panus conchatus, Cyathus stercoreus and Pleurotus florida respectively. It was found that kappa number decreased and the brightness increased for Soda-AQ pulps from the reed treated by Pleurotus florida and Panus conchatus, but it was reverse for the pulp from reed treated by Cyathus stercoreus. The result indicated that white rot fungi Pleurotus florida and Panus conchatus were selective to degrade lignin in reed, which were good for biopulping, but Cyathus stercoreus was preferential to degrade cellulose, which was not good for biopulping.

Enzymatic activities and kinetic properties of β-glucosidase from selected white rot fungi

Beta-glucosidase is among the suite of enzymes produced by white rot fungi (WRF) to biodegrade plant biomass. This study investigated the enzymatic activities and kinetic properties of β-glucosidase from seventeen WRF comprised of the following species from various geographical locations: Pleurotus ostreatus, Auricularia auricular, Polyporus squamosus, Trametes versicolor, Lentinula edodes, and Grifola frondosa. All the WRF studied showed β-glucosidase activities. Significant variations in protein and carbohydrate contents were also recorded. Beta-glucosidase activities after 30 min of incubation ranged from 6.4 μg (T. versicolor) to 225 μg (G. frondosa). The calculated kinetic constant (Km) ranged from 0.47 μM (A. auricular-1120) to 719 μM (L. edodes-7). The Vmax depending on the kinetic transformation model ranged from 0.21 μg·min-1 (T. versicolor) to 9.70 μg·min-1 (G. frondosa-28). Beta-glucosidase activities also exhibited pH optima between 3.5 and 5.0 while temperature optima were between 60°C and 70°C with some media exhibiting a secondary temperature peak at 90°C attributable to the presence of thermostable isoenzyme. WRF if appropriately screened and purified can be harnessed to potentially improve the bio-conversion of cellulose to glucose and also facilitate efficient plant biomass biodegradation and production of useful plant bio-products.

Interfacial processes and mechanisms of synergistic degradation of dichlorobiphenyl by white rot fungi and magnetite nanoparticles

The rapid increase in the artificial syntheses of organic pollutants has raised widespread concern.However,the mechanisms by which fungi degrade these new organic pollutants in the environment and adapt to environmental stressors remain unclear.In this study,Phanerochaete chrysosporium,a model white rot fungus,was used to explore the interfacial processes and mechanisms for synergistic degradation of 4,4′-dichlorobiphenyl(PCB15)with magnetite nanoparticles.The results showed that after 3 and 5 days of cultivation with Phanerochaete chrysosporium alone,the rates for PCB15 degradation were 32%and 65%,respectively,indicating that the white rot fungus itself was able to degrade the organic pollutant.Moreover,the addition of magnetite nanoparticles significantly enhanced the degradation of PCB15 by Phanerochaete chrysosporium.After cocultivation for 3 and 5 days,the rates for PCB15 degradation increased to 42%and 84%,respectively.Synchrotron radiation-based Fourier transform infrared spectromicroscopy(SR-FTIR)showed that the magnetite particles were tightly adhered to the fungal hyphae and were unevenly distributed on the hyphal surfaces.Furthermore,cocultivation of the fungus and magnetite nanoparticles significantly enhanced the nanozymatic activity of magnetite.A linear regression model provided a significantly negative correlation(r=−0.96,p<0.001)between the nanozymatic activity of the magnetite and the concentration ratio of the PCB15,supporting the hypothesis that white rot fungi degraded the PCB15 by enhancing the nanozyme activity of magnetite.High-resolution X-ray photoelectron spectroscopy(XPS)revealed that the nanozymatic activity of magnetite was mainly governed by oxygen vacancies on the mineral surfaces rather than the iron valence.Together,these findings increase our understanding of the powerful capabilities of fungi in terms of stress resistance and adaptation to extreme environments and provide new insights into fungal-mediated degradation of organic pollutants for soil remediation in contaminated sites.

The anti-hyperlipidemia activities of six herbs before and after fermentation with white rot fungi

Hyperlipidemia has high morbidity. We explored the novel activities of six Chinese herbs before and after fermentation for preventing hyperlipidemia. The herbs were fermented with white rot fungi Ganoderma lucidum, a strain of EN2. Lovastatin was used as the positive control. Mice were treated with those herbs before and after fermentation treatment for 15 d and then injected peritoneally with Triton 3393. After the treatment, the serum total cholesterol （TC） and triglyceride （TG） were measured. More- over, the changes of the ingredients of those herbs were analyzed by fingerprint chromatography. The results showed that Herba leonuri before fermentation, Ramulus mori and Caulis lonicerae after fermentation, Radix sophoraeflavescentis before and after fermentation showed activities to prevent hypertriglyceridemia, while Ramulus mori and Herba leonuri before fermentation showed activities to prevent hypercholesterolemia. In addition, some new ingredients were appeared after fermentation. In conclusion, the novel activities of these herbs to prevent hyperlipidemia were identified and the new ingredients that emerged after fermentation warrant further exploration.

White-rot Fungus Growth Conditions and Its Metabolic Kinetic Models

To investigate the growth conditions of white-rot fungus and simulate its metabolism kinetic models, the rules how the factors such as biomass, culture fluid, pH value, glucose consumption and exopolysaccharides generation, etc., changed during the batch culture process of white-rot fungi by using an air-lift fermenter, as well as metabolic kinetics of white-rot fungi were studied. Based on Logistic equation, Luedeking-Piret equation and experimental data, the correlation model parameters of mycelia biomass, glucose consumption and exopolysaccharide generation were obtained and found to be change with time in metabolism process. Detailedly, μm=0.071 8 h-1,α= 0.831 8 g/(g·h), β= 0.002 g/(g·h), b1=0.016 3 g/(g·h) and b2=3.023 3 g/(g·h). Hence the mycelial growth kinetic model, exopolysaccharide generation kinetic model and substrate consumption kinetic model which describe fermentation process of white-rot fungi were established. Meanwhile, the experimental data were verified by this model, and a good fitting result with an average relative error less than 10% between the data obtained from experiments and the model was yielded. The results show that these models can predict the growth and metabolic rules of white-rot fungus, the fermentation process of exopolysaccharides and the kinetic mechanism of white-rot fungus accurately.

γ-Fe_2O_3 nanoparticle-facilitated bisphenol A degradation by white rot fungus

The effect of γ-Fe_2O_3 nanoparticles on bisphenol A(BPA)biodegradation by white rot fungus(Pleurotus ostreatus)was investigated.Interestingly,the addition of γ-Fe_2O_3 nanoparticles enhanced BPA degradation efficiency by as much as 32% after 3 d in the presence of an environmentally relevant concentration of H_2O_2.The γ-Fe_2O_3-induced BPA degradation enhancement was not due to a commonly assumed Fenton-like reaction catalyzed by γ-Fe_2O_3 or dissolved Fe^(3+) ions.However,γ-Fe_2O_3was bioreduced to Fe_3O_4,which was more efficient at catalyzing the Fenton reaction,producing a highly active hydroxyl radical.The bioreduction of γ-Fe_2O_3 was confirmed by X-ray powder diffraction analysis.This study elucidates the potential biotransformation of nanoparticles in the environment and broadens the application of iron oxide nanoparticles for improved pollutant control.

Cometabolic degradation of veratryl alcohol and biphenyl by white rot fungus under nitrogen nutrition-rich condition

In this paper, changes of enzymes involved in the degradation of recalcitrant aromatic pollutants from white rot fungus Phlebia radiata I 5 6 and cometabolism of biphenyl and varatryl alcohol by this fungus under nitrogen nutrition rich were studied. Results from the experiment showed that C/N concentration ratio in the culture media played an important role on the activity of LiP. Under the condition of high concentration ratio of C/N or N/C, activity of LiP was higher, but higher activity of MnP only followed the low concentration of glucose or tartrate ammonium concentration in the media, when concentration of glucose or tartrate ammonium was more than 0 01 mol/L, the activity of MnP dropped down quickly. Veratryl alcohol increased the activity of LiP and MnP as well as the amount of ·OH radical free under different concentration of nitrogen or carbon source; ascorbic acid, a scavenger of ·OH radical free, brought the opposite effect to that of the veratryl alcohol on the LiP and MnP activity. Under nitrogen nutrition rich condition removal percentage of biphenyl was lower, however, under cometabolic condition of veratryl alcohol and biphenyl, the degradation was enhanced obviously, moreover, intermediate products accumulated in the media during the cometabolic degradation process of biphenyl and veratryl alcohol was different from these which was found in the process of separate degradation of biphenyl or veratryl alcohol.

Biodegradation of Gaseous Chlorobenzene by White-rot Fungus Phanerochaete chrysosporium

Objective To evaluate the effect of white rot fungus Phanerochaete chrysosporium on removal of gaseous chlorobenzene. Methods Fungal mycelium mixed with a liquid medium was placed into airtight bottles. A certain amount of chlorobenzene was injected into the headspace of the bottles under different conditions. At a certain interval, the concentrations in the headspace were analyzed to evaluate the degradation of chlorobenzene by P. chrysosporium. Results The degradation effects of P. chrysosporium on chlorobenzene under different conditions were investigated. The difference in the optimum temperature for the growth of the fungi and chlorobenzene degradation was observed. The data indicated that a lower temperature （28℃） would promote the degradation of chlorobenzene than the optimum temperature for the growth of the fungi （37℃）. A low nitrogen source concentration （30 mg N/L） had a better effect on degrading chlorobenzene than a high nitrogen source concentration （higher than 100 mg N/L）. A high initial concentration （over 1100 mg/m3） of chlorobenzene showed an inhibiting effect on degradation by P chrysosporium. A maximum removal efficiency of 95% was achieved at the initial concentration of 550 mg/m3. Conclusion P. chrysosporium has a rather good ability to remove gaseous chlorobeuzene. A low nitrogen source concentration and a low temperature promote the removal of chlorobenzene by P. chrysosporium. However, a high initial chlorobenzene concentration can inhibit chlorobenzene degradation.

Comparative study on using carbon or nitrogen limited medium to culture white rot fungi for reactive brilliant red dye K-2BP decolotization under non-sterile conditions

In order to explore ways for the application of white rot fungus in dye effluent treatment under non-sterile conditions, experiment on decolorization of reactive brilliant red was carried out, employing nitrogen-limited and carbon-limited medium with C/N ratio of 56/2.2 and 28/44 (in mmol/L), respectively. The results showed that the decolorization rate reached 92% while culturing white rot fungus with ni- trogen-limited medium; however, the decolorization process ended in carbon-limited medium (n(C)/n(N) = 28/44) because of bacterial contamination. In addition, pH rose up to 9.31 after 4 d of decolorization, which was caused by bacterial contamination in the carbon-limited system. Therefore, it is concluded that nitrogen-limited medium can inhibit bacterial growth to some extent while carbon-limited medium is more easily contaminated by bacteria. Nitrogen-limited medium is more suitable in culture of white rot fungus for decolorization of reactive dye. Medium with the ability of inhibiting yeast growth should be developed by adjusting other components of nitrogen-limited medium.

Effects of White-Rot Fungi Composting on Wood Powder-Chicken Manure Mixture

[ Objective] To explore the possibility of treating livestock manure with white-rot fungi. [Method] The wood powder-chicken manure mixture was respectively composted by three kinds of white-rot fungi, the weight of lignin, cellulose, protein, fat, ash and crude polysaccharide as well as the mycelial growth was determined during this process. [ Result] The mixture was better composted with white-rot fungi than the control. The best effect was achieved in P. ostreatus composting group. In this group, the rate of weight reduction, lignin degradation and cellulose degradation were respectively 15.68% （6.79 times as great as that of the control group）, 39.92% （6.54 times as great as that of the control group） and 32.26% （2.77 times as great as that of the control group）. The weight of protein and fat were increased by 31.68% and 146.58%, respectively. The content of crude polysaccharide was 2.43%. No crude polysaccharide was detected, and the weight of protein and fat decreased by 21.96% and 70.99%, respectively. [ Conclusion] It is feasible to compost livestock and poultry manure with white-rot fungi.

Transcriptome Analysis of White-Rot Fungi in Response to Lignocellulose or Lignocellulose-Derived Material Using RNA Sequencing Technology

White-rot fungi are the only organisms that can completely degrade all components of lignocellulosic biomass, including the recalcitrant lignin polymer. Lignin degradation is important for the industrial application of lignocellulosic biomass as a raw material for producing value-added chemicals and materials. Therefore, elucidating the lignin degradation mechanism in white-rot fungi will help researchers develop efficient and eco-friendly methods enabling the production of value-added chemicals from lignocellulosic biomass. A transcriptome analysis is an effective way to compare gene expression patterns between different samples under diverse conditions and can provide insights into biological processes. The democratization of next-generation sequencing technology, especially RNA-sequencing, has made transcriptome sequencing and analysis a common research approach for many laboratories. In this review, we focus on the transcriptome profiles of two well-characterized white-rot fungi (Phanerochaete chrysosporium and Dichomitus squalens) in response to various lignocellulosic materials. The application of RNA-seq technology combining with other techniques remains the best approach for investigating fungal secretomes and elucidating the mechanisms of fungal responses to lignocellulose.

不同条件下白腐真菌多糖调控合成的铁(氢)氧化物的特征

对白腐真菌胞外多糖在铁(氢)氧化物的生物形成过程中的作用展开具体研究,使用傅里叶红外光谱仪研究了不同多糖浓度、陈化时间、Fe^(3+)初始浓度、矿化体系pH和陈化温度条件下白腐真菌胞外多糖调控形成的铁(氢)氧化物的特征,探究了在不同条件下白腐真菌生物矿化的铁(氢)氧化物的晶型组成和不同相之间的转化规律。结果表明:适当增大多糖含量可促进铁(氢)氧化物在多糖分子中成核,且陈化过程中铁(氢)氧化物的晶型和结晶程度均会发生变化;Fe^(3+)初始浓度的升高有助于提高铁(氢)氧化物羟基结合态的稳定程度;酸性条件下有利于α-FeOOH的形成,而在碱性条件下则有利于α-Fe_(2)O_(3)的形成;温度的适当升高有利于Fe—O结晶度的提高,温度的进一步升高有利于铁(氢)氧化物转化成更稳定的相。

白腐菌改性黄芪药渣吸附脱色模拟染料废水的研究

本文用白腐真菌发酵改性黄芪药渣,制备得到具有对亚甲基蓝模拟染料废水有较好吸附效果的吸附剂,并研究了初始pH值、吸附反应温度、吸附剂加入量、吸附时长对亚甲基蓝吸附效果的影响。实验结果表明,在溶液初始pH值为6~8、吸附温度为30℃、改性黄芪药渣加入量为0.1g、吸附时长为4h的条件下,改性黄芪药渣对亚甲基蓝的吸附率可达91.03%。