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.

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.

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.

Bio-solubilization of Chinese lignite I:extra-cellular protein analysis

A white rot fungus strain, Trichoderma sp.AH, was isolated from rotten wood in Fushun and used to study the mechanism of lignite bio-solubilization.The results showed that nitric acid pretreated Fushun lignite was solubilized by T.sp.AH and that extracellular proteins from T.sp.AH were correlated with the lignite bio-solubilization results.In the presence of Fushun lignite the extracellular protein concentration from T.sp.AH was 4.5 g/L while the concentration was 3 g/L in the absence of Fushun lignite.Sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE) of the extracellular proteins detected at least four new protein bands after the T.sp.AH had solubilized the lignite.Enzyme color reactions showed that extracellular proteins from T.sp.AH mainly consisted of phenol-oxidases, but that lignin decomposition enzymes such as laccase, peroxidase and manganese peroxidases were not present.

A Simple Structure Model for Enzyme Production by Phanerochaete chrysosporium

In order to understand the behavior of ligninolytic enzyme production by white rot fungi Phanerochaete chrysosporium, study on time courses and a mathematical model for the production of lignin peroxidase (LiP) and manganese peroxidase (MnP) of the fungi was undertaken. Based on the Monod-Jacob operon model, the ligninolytic enzyme would be synthesized in the absence of a related repressor. The repressor is assumed to be active in the presence of ammonia nitrogen, and as combined as co-repressor, it causes the inhibition of enzyme synthesis. The model can explain the mechanism of extracellular ligninolytic enzyme production by white rot fungi. The results,as predicted by the model, correspond closely to those observed in experimental studies. In addition, some light is also shed on unmeasured variables, such as the concentrations of repressor and mRNA that are related to the enzyme synthesis.

To enhance the reproduction of Phanerochaete chrysosporium by adding natural lixiviums in liquid medium

Great promotion to the reproduction of white rot fungus Phanerochaete chrysosporium by adding natural lixiviums such as from wood, maize core and potato in liquid medium was found in this research. Incubated in the liquid medium contained 10 mg/L glucose as carbon source with natural lixiviums for three days, the production of mycelium pellet reaches more than 80 g/L, which is 5 times more than that of without natural lixiviums. Incubated in the liquid medium contained 5 mg/L glucose as carbon source with natural lixiviums for three days, the production of mycelium pellet can reach 69.5 g/L, while the production in the medium without natural lixiviums is very low. When the liquid medium contained 1—20 g/L glucose as carbon source, the production of mycelium pellet in 3 d can only reach 12.5 g/L to 14.5 g/L. The fungus in the medium with potato lixiviums are easily contaminated by other microorganisms and in the medium with maize core lixiviums are easily bulking, while in the medium with wood lixiviums are neither easily contaminated nor bulking. Medium with wood lixiviums can produce more pellet than other medium, endure contamination and keep better sedimentation capacity. So that, wood lixivium is better additive to the culture of white rot fungi in liquid medium. Addition of the mixture of wood, maize core and potato lixiviums is of advantage to the production of mycelium pellet. The difference of the production in the medium with different amount of wood lixiviums showed little in the first 3 d, while it expanded after 3 d. Wood lixiviums stimulate the growth of P. chrysosporium instead of supply organics which fungi need.