Required equilibrium studies for designing a three-phase bioreactor to degrade trichloroethylene (TCE) and tetrachloroethylene (PCE) by Trametes versicolor

This paper aims to investigate the three-phase equilibriums to design a bioreactor to degrade trichloroethylene (TCE) and tetrachloroethylene (PCE) by the white-rot fungus Trametes versicolor. The vapour–liquid equilibrium constants were obtained from bibliographic values and these values are 0.392 for TCE and 0.723 for PCE, which show that these two compounds are very volatile. Adsorption of TCE and PCE by dead biomass pellets was studied. Due to the low concentration range studied for both compounds, the linear equation is enough to describe the adsorption equilibrium. The adsorption parameters are 0.110 and 0.176 for TCE and PCE, respectively. Then the equilibrium information obtained was used to calculate the distribution of these contaminants in a three-phase bioreactor in specific degradation conditions and despite it is checked that adsorption is not very high, it is significant (between 12.0% and 12.8%). Moreover, a comparison between TCE and PCE experimental and calculated degradation yields was done to validate the linear isotherm.     

Tetrachloroethylene and hexachloroethane degradation in Fe(III) and Fe(III)–citrate catalyzed Fenton systems

BACKGROUND: Tetrachloroethylene (PCE) and hexachloroethane (HCA) degradation, individually and in mixture, is investigated by Fe(III) or Fe(III)‐citrate initiated Fenton reaction under a range of hydrogen peroxide (H₂O₂) concentrations to illustrate the applicability and constraints of Fenton chemistry in degrading contaminants in polluted groundwater. RESULTS: In individual solutions Fe(III) rapidly degraded PCE for all H₂O₂ concentrations, but HCA at ≥ 0.2 mol L^?1 H₂O₂; the apparent PCE degradation rate initially increased but then decreased with increasing H₂O₂, while the HCA degradation rate was either unaffected or increased. With Fe(III)‐citrate PCE degradation was lower and no HCA degradation occurred. PCE degradation was lower in PCE‐HCA mixture, but the trend with H₂O₂ concentration was similar to the individual chemical; for HCA the residual was smaller for higher H₂O₂ concentration, but the apparent degradation rate constant was unaffected. CONCLUSION: Fe(III) catalyzed reactions can potentially degrade chemicals through reductive as well as oxidative transformations. Degradation of chemicals in mixtures occurs at a slower rate due to competition for radical moieties. The Fe(III)‐citrate complex further slowed chemical transformation. This study expands on the use of different forms of iron to catalyze the Fenton reaction to degrade chemicals. Copyright © 2012 Society of Chemical Industry     

The Wood Preservative Potentials of Valonia,Chestnut, Tara and Sulphited Oak Tannins

This study investigated antifungal properties of four different tannins as potential environmentally friendly wood preservatives. Scots pine wood samples were impregnated with 3, 5, 10, and 15% valonia, chestnut, tara, and sulphited oak tannins, and then were exposed to brown rot fungi Coniophora puteana and Postia placenta, and white rot fungi Trametes versicolor and Pleurotus ostreatus attack to determine the best tannin type and the optimum concentration level for sufficient decay resistance. Leaching test was conducted in order to evaluate any loss in effectiveness in decay resistance due to possibility of tannin leaching. Tannins were found efficacious in suppressing brown rot fungi attacks when no leaching prior the decay test was used, however, they seemed to be ineffective against white rot fungi attacks. The lowest weight losses were obtained with valonia and chestnut tannins both for brown and white rot fungi probable related with their high ellagic tannin content.     

Correlation of 13C‐NMR analysis with fungal decay tests of polymeric structural wood constituents. I. Basidiomycetes

Heat treatment at relatively high temperatures (from 150 to 260°C) is an effective method to improve the durability of wood. This study investigates the reasons for the decay resistance of heat‐treated and nontreated wood with respect to the polymeric structural constituents by solid‐state cross‐polarization/magic‐angle spinning (CP–MAS) ¹³C‐NMR analysis before and after exposure to brown rot and white rot fungi. An industrial two‐stage heat‐treatment method under relatively mild conditions (<200°C) has been used to treat the samples. Brown rot fungi attack polymeric carbohydrates of nontreated Scots pine sapwood at C4, resulting in cleavage and eventually depolymerization of cellulose and hemicelluloses. The attack at the carbohydrate C6, which has never been observed before, is remarkable because the C6 ? CH₂OH group has no covalent structural function but acts in fixing the three‐dimensional carbohydrate configuration just by secondary forces. The ? CH₂OH group carries ? OH, which forms some of the strongest hydrogen bonds in the structure of the crystalline native cellulose. It is suggested that the fungus tries to cleave this group to open the cellulose crystalline structure into an amorphous structure to decrease its water repellency to facilitate enzymatic cellulose degradation. Considerable degradation of the hemicelluloses occurs during brown rot fungal exposure, whereas in general the attack on lignin is rather limited, being mainly demethoxylation. However, Gloeophyllum trabeum is an active brown rot fungus in the (partial) degradation of lignin because there is some indication of ring opening of the aromatic ring of lignin during fungal exposure. Aromatic ring opening has also been observed after exposure to Coriolus versicolor, a white rot fungus. The demethoxylation of lignin and some attack on wood carbohydrates are also characteristic of the attack of this white rot fungus. The CP–MAS ¹³C‐NMR spectra of heat‐treated Norway spruce reveal similarities but also clear differences after fungal exposure in comparison with nontreated Scots pine sapwood. Brown rot fungi seem to have a preference to attack the carbohydrates of heat‐treated wood at C4 and especially C1, cleaving the skeleton of cellulose and glucomannans. In untreated Scots pine sapwood, this attack mainly occurs at C4, the nonreducing end of the glucose unit. An attack on the out‐of‐the‐ring alcoholic group ? CH₂OH of the carbohydrates of heat‐treated Norway spruce is less obvious than that in untreated Scots pine. The attack on C3/C5 of the carbohydrates is remarkable, indicating ring opening of the glucose units, which has not been observed in nontreated Scots pine sapwood. Lignin degradation is limited to demethoxylation, and low or no aromatic ring opening is observed, even after C. versicolor exposure. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2639–2649, 2006     

Fungal degradation of wood‐plastic composites and evaluation using dynamic mechanical analysis

Small samples of two wood–polyethylene (HDPE) composite formulations were incubated with either the white‐rot fungus Trametes versicolor or the brown‐rot fungus Gloeophyllum trabeum for 24 and 77 days in an agar‐block test. Noninoculated, side‐matched controls were employed in the tests to serve as references, and solid wood samples of yellow‐poplar (Liriodendron tulipifera L.) inoculated with T. versicolor were included as positive controls. Potential changes in storage and loss moduli because of fungal colonization and moisture were determined using dynamic mechanical analysis, whereas weight loss and visual observation served as indicators of fungal decay. Severe losses in storage modulus (E′) and loss modulus (E″) following incubation of yellow‐poplar with T. versicolor were observed. However, the E′ of the two wood–plastic composite (WPC) formulations increased after 24 days of incubation with T. versicolor. The same effect was observed for G. trabeum, but only in one formulation. The increase of E′ was attributed to a reinforcing effect of the fungal hyphae present in the interfacial gaps between the wood filler and the polymer matrix. Dynamic temperature scans revealed a peak in E″ between 30°C and 63°C, depending on the frequency and fungal treatment. The peak temperature of E″ represents the α‐transition of HDPE. Increased activation energies were required for the α‐transition in WPC samples incubated with T. versicolor for 77 days as compared to controls. This observation confirmed that incubation of WPC with T. versicolor improved interfacial adhesion and reinforced the composite under the assay conditions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3138–3146, 2006     

Screening of white rot fungi for the treatment of olive mill waste-waters

Several white rot fungi were evaluated for their ability to decolorize olive mill waste-waters (OMW). Among these, Phanerochaete chrysosporium showed the highest potential for the biological depollution of OMW. Approximately 65% of the color and 73% of the chemical oxygen demand (COD) were removed by P. chrysosporium strain HD. Phlebia radiata, Dichomitus squalens, Polyporus frondosus and Coriolus versicolor could also decolorize the OMW but to a lesser extent. The different abilities of these white rot fungi to decolorize OMW correlated with their rates of depolymerization of high molecular weight aromatics and the degradation of the low molecular weight aromatic compounds. Fourteen strains of P. chrysosporium were compared on the basis of their lignin peroxidase (LiP) production, OMW decolorization and residual material dry weight. High lignin peroxidase producer strains, such as strains HD and BKM-F-1767, showed the highest rates of OMW decolorization, P. chrysosporium strains 79–36 and FP 104297 (low LiP producer strains) did not exhibit any decolorization activity.     

固定化白腐菌对造纸废水的生物降解研究

就具有较强木质素降解能力的白腐菌对造纸废水的降解效果及条件进行了初步研究.分别采用固定化白腐菌和悬浮态白腐菌在不同接种量下对造纸废水进行降解,对降解过程中的白腐菌生长量、pH、COD、木质素含量等废水降解指标进行测定.结果显示两种不同状态下的白腐菌均能降解造纸废水,但它们的降解程度不同.其中固定化白腐菌降解木质素效果较好,且呈现较明显规律,说明固定化的白腐菌较悬浮态的白腐菌更具有降解造纸废水的潜在能力.     

Oxalate decarboxylase of Trametes versicolor: biochemical characterization and performance in bleaching filtrates from the pulp and paper industry

BACKGROUND: Oxalate decarboxylase (ODC) from acid‐induced cultures of the white‐rot fungus Trametes versicolor was purified and characterized with respect to its biochemical properties and the possibility to utilize the enzyme for treatment of process water with the intention to prevent problems with calcium‐oxalate scaling in the pulp and paper industry. RESULTS: Purified T. versicolor ODC was identified by tandem mass spectrometry. As estimated by using SDS‐PAGE, the molecular mass was 69 kDa, and 60 kDa after deglycosylation with N‐glycosidase F. The pH optimum was 2.5 and the temperature optimum was 40–45 °C. The effects of ten potential inhibitors in industrial filtrates were examined. The enzyme was sensitive to low concentrations (0.1 mmol L^?1) of chlorite and sulfite. T. versicolor ODC exhibited activity in 16 filtrates collected from mechanical pulping and kraft pulping. It had higher activity than ODC from Aspergillus niger in all of the filtrates and higher activity than oxalate oxidase from barley in all filtrates except two. CONCLUSIONS: The investigation shows basic biochemical properties of T. versicolor ODC and indicates that the enzyme may be useful for treatment of industrial filtrates under acidic conditions. Copyright © 2012 Society of Chemical Industry     

Influence of mediator immobilization on the electrochemically assisted microbial dechlorination of trichloroethene (TCE) and cis‐dichloroethene (cis‐DCE)

BACKGROUND: A bioelectrochemical process for trichloroethene (TCE) dechlorination was developed. In this new process, a solid‐state electrode polarized to ?450 mV versus the standard hydrogen electrode (SHE), in combination with a redox mediator (i.e., methyl viologen, MV) is employed as an electron donor for the microbial reductive dechlorination of TCE. In this study we compared the performance of the process with the redox mediator immobilized at the surface of electrodes or dissolved in the bulk liquid, using both a culture highly enriched in Desulfitobacterium spp., capable of dechlorinating TCE to cis‐dichloroethene (cis‐DCE), and a culture highly enriched in Dehalococcoides spp. capable of dechlorinating cis‐DCE to ethene. RESULTS: Short‐term potentiostatic (?450 mV versus SHE) experiments showed that TCE or cis‐DCE was dechlorinated both in the presence of soluble (500 µmol L^?1) and immobilized MV. However, TCE or cis‐DCE dechlorination rates with MV‐modified electrodes were remarkably lower than with soluble MV. Both cultures produced significant amounts of H₂ in the presence of electrically reduced, soluble MV, whereas no H₂ was produced when the mediator was immobilized at the electrode surface, regardless of the potential applied to the electrode, in the range ?425 to ?500 mV versus SHE. CONCLUSIONS: The process, operated with modified electrodes, supports the microbial dechlorination of TCE to ethene. Immobilization not only allows retention of the mediator within the system, but also increases process efficiency by preventing bioelectrochemical H₂ formation. On the other hand, strategies to increase dechlorination rates with modified electrodes need to be developed. Copyright © 2009 Society of Chemical Industry     

Controlled release of biocides in solid wood. III. Preparation and characterization of surfactant‐free nanoparticles

Polymeric nanoparticles containing the fungicides tebuconazole and chlorothalonil were prepared by a simple, surfactant‐free method and found to have significantly smaller median particle diameters and more stable aqueous suspensions than their surfactant‐stabilized counterparts. These more stable suspensions were delivered into southern yellow pine and birch wood with greater efficiency than the equivalent surfactant‐stabilized nanoparticle suspensions. We found that the suspensions protected the treated wood against fungal attack by Gloeophyllum trabeum, a common brown rot wood decay fungus, and Trametes versicolor, a common white rot wood decay fungus, at low tebuconazole and chlorothalonil contents in the wood. Southern pine lost 5% or less of its mass after 55 days of exposure to G. trabeum when the tebuconazole or chlorothalonil content in the wood was only 0.4 kg/m³, while a tebuconazole or chlorothalonil content of 0.8 kg/m³ in birch wood was sufficient to bring its mass loss to less than 5% after 55 days of exposure to T. versicolor. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 615–621, 2002     

Evaluation of the Lignolytic Effect of the White‐Rot Fungi Ceriporiopsis Sp,Pleurotus Sp,and Phlebia Sp on Industrial Pinus Radiata Logs

Abstract

Pretreatment of pinus Radiata logs with the white‐rot fungi Ceriporiopsis sp (9C), Pleurotus sp (9P), and Phlebia sp (24P), under field conditions was studied. The lignin content was evaluated by gravimetric techniques (Klason lignin), FTIR spectroscopy, and gas chromatography. A control sample and samples treated for 90 days with each of the fungi were analyzed. The ability of the fungi to degrade the lignin was in the order Phlebia sp (24P) > Ceriporiopsis sp (9C) > Pleurotus sp (9P).     

Physico‐mechanical and decay resistance properties of chemically modified tropical wood material

In this present research, several kinds of selected tropical light hardwoods were chemically modified with benzene diazonium salt to improve their physico‐mechanical and decay resistance properties. Benzene diazonium salt underwent a coupling reaction with wood which was confirmed through fourier transform infrared spectroscopic analysis. The compressive modulus of the treated wood increased, whereas modulus of rupture was shown to decrease on treatment. Water absorption was also found to decrease considerably after modification. The modified wood samples had higher hardness (Shore D) value compared to that of the control ones. The wood was exposed to two types of fungi; white‐rot (Polyporus versicolor) and brown‐rot (Postia placenta), for 12 weeks and then decay was assessed through weight loss percentage (%). A significant improvement was found in the modified wood compared to the control wood. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Phosgene-Free Photocatalytic Degradation of TCE and PCE Vapors with Au/TiO2

Photocatalytic oxidation of trichloroethylene (TCE) and tetrachloroethylene (PCE) in air had been carried out with TiO₂ film alone and Au/TiO₂ film. On the TiO₂ film TCE and PCE were converted mainly into toxic COCl₂, while COCl₂ free TEC and PCE oxidation could be achieved with Au/TiO₂.     

Evaluation of basidiomycetous fungi for pretreatment of contaminated soil

BACKGROUND: For most dioxin‐contaminated sawmill soils, combustion is recommended. However, the process may be inefficient if the soil has a high organic matter content. The use of saprotrophic basidiomycetous fungi is an alternative for pretreatment of this kind of soil. A total of 147 fungi were evaluated for their ability to grow in sawmill soil. From this screening, the best soil colonizing fungi were selected to study their enzyme activities and degradation of soil organic matter. Pine (Pinus sylvestris) bark was used as a co‐substrate to propagate the fungi into the soil. The activities of manganese peroxidase (MnP), laccase, endo‐1,4‐β‐glucanase, endo‐1,4‐β‐xylanase, and endo‐1,4‐β‐mannanase were analysed from the inocula and fungal treated soil. RESULTS: The screening revealed that 56 out of 147 fungi were able to grow in non‐sterile soil, and most of them were litter‐decomposing fungi (LDF). In pine bark cultures, the highest enzyme activities were observed with Phanerochaete velutina, which produced 5 U g^?1 of MnP. The activity of endo‐1,4‐β‐glucanase was generally higher than that of other hydrolytic enzymes. The highest carbon loss from soil with a high organic matter content was achieved by P. velutina (3.4%) and Stropharia rugosoannulata (2.4%). CONCLUSIONS: Many LDF, and in addition the white‐rot fungus P. velutina, are potential degraders of soil organic matter since they showed good growth and respiratory activity. Pine bark was a suitable lignocellulosic co‐substrate and a good promoter of MnP activity. Copyright © 2009 Society of Chemical Industry     

Black liquor detoxification by laccase of Trametes versicolor pellets

Black liquors from a soda pulping mill were treated with the white‐rot fungus Trametes versicolor to detoxify and reduce colour, aromatic compounds and chemical oxygen demand (COD). The fungus was used in the form of pellets in aerated reactors (fluidized, stirred and air‐pulsed reactors). Reductions in colour and aromatic compounds of 70–80% and in COD of 60% were achieved. During the different experiments, laccase activity was detected but neither lignin peroxidase (LiP) nor manganese peroxidase activities were detected, although T versicolor is able to produce these enzymes. Experiments also showed a LiP activity inhibitory effect produced by lignin. From the results obtained, it can be concluded that there is a relationship between laccase production and toxicity reduction. This correlation responds to the equation Laccase production = 1.57 LN (toxicity reduction) ?16.40. Copyright © 2003 Society of Chemical Industry     

白腐真菌膜生物反应器处理复配染料废水营养源调控研究

构建白腐真菌膜生物反应器降解复配染料废水,研究营养源调控对反应器降解过程的影响。利用通过野外采集及紫外诱变得到的十五种白腐真菌,通过染料生产废水的摇瓶脱色实验,筛选出脱色能力最强的12社诱1菌种（出水色度由初始时的4000倍变为处理72h之后的15倍）作为后续实验的研究菌种。在白腐真菌膜生物反应器营养源调控研究中,得到如下结论：将碳源浓度从30g／L降低到10g／L、氮源浓度从560mgN／L（20mmol／L尿素）降低到56mgN／L（2mmol／L尿素）后,同样获得了良好的复配染料脱色效果。     

Identification of Anti-Wood Rot Compounds in Teak (Tectona grandis L.f.) Sawdust Extract

Abstract

The tropical hardwood sawdust of Tectona grandis L.f. from the wood processing industry was extracted and tested for anti-wood rot activity. Tectona grandis extract inhibited the brown rot fungi Gloeophyllum sepiarium, Gloeophyllum trabeum, Piptoporus betulinus and Serpula lacrymans, and the white rot fungi Bjerkandera adusta, Merulius tremellosus, and Phlebia brevispora. Centrifugal partition chromatography was used to separate these compounds using n-hexane-MeOH-H₂O (50:47.5:2.5) as a solvent system. The compounds deoxylapachol, tectoquinone, 2-hydroxymethylanthraquinone, 3′-OH-deoxyisolapachol (2-[(1E)-3-hydroxy-3-methylbut-1-enyl]naphthoquinone), hemitectol (2,2-dimethyl-2H-benzo[h]chromen-6-ol), and tectol were isolated from Tectona grandis sawdust CHCl₃-MeOH (1:1) extract. Deoxylapachol inhibited the brown rot fungi Gloeophyllum sepiarium CBS 353.74 and Gloeophyllum trabeum CBS 318.50 and the white rot fungi Merulius tremellosus CBS 280.73 and Phlebia brevispora CBS 509.92. Hemitectol together with tectol showed a high percentage of cellulase inhibition followed by 3′-OH-deoxyisolapachol and deoxylapachol.     

Effect of bio‐oil and epoxidized linseed oil on physical,mechanical, and biological properties of treated wood

In this article, the effects of bio‐oil and epoxidized linseed oil (ELO) on water absorption, tangential swelling, decay and insect resistance, thermo‐gravimetric analysis, and mechanical properties of treated wood samples were studied. The bio‐oil used in this article was by‐product of ThermoWood thermal modification process. Linseed oil and hydrogen peroxide were used to prepare ELO. The results indicated that the samples treated with bio‐oil had lower water absorption than that of the control group. The second treatment with ELO significantly reduced further the water absorption. The decay resistance of treated wood samples with 20% of bio‐oil against brown (Coniophora puteana) and white rot (Trametes versicolor) fungi was very high. According to the insect test results, increasing bio‐oil concentration from 10% to 20% significantly decreased surviving rate of Hylotrupes bajulus. Thermo‐gravimetric analysis showed that all treated samples had higher initial deterioration temperature than that of the control group. Regarding the wood strength, the impregnated bio‐oil generally reduced the mechanical properties of wood except modulus of elasticity (MOE). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1562–1569, 2013     

Destruction of trichloroethylene (TCE) and trichloromethane (TCM) in the presence of selected VOCs over Pt-Pd-based catalyst

Catalytic oxidation of trichloroethylene (TCE) and trichloromethane (TCM) oxidized alone and in two-component mixtures with selected volatile organic compounds (VOCs) such as toluene, n-hexane, ethanol or acetone was investigated over a Pt-Pd-based catalyst on a monolithic, metallic, γ-Al₂O₃-washcoated support. TCE and TCM were more difficult to oxidize than VOCs and temperatures of their 50% conversion (T_50%) amouted to 420 and 330 °C, respectively. All the VOCs added were found to enhance the conversion of the two chlorinated compounds, drecreasing T_50% by 20 °C, at the most, for TCM in the presence of toluene and by 50 °C for TCE in the presence of acetone. Both the chlorinated compounds lowered the conversion of the VOCs added (except that of toluene), and this lowering was particularly distinct with n-heptane; they also raised the concentration of acetaldehyde formed during the oxidation of oxyderivative compounds.     

Inoculation of Filamentous Fungi in Manufactured Gas Plant Site Soils and PAH Transformation

Solid carriers have been developed to inoculate Trametes versicolor and Cunninghamella elegans into manufactured gas plant site soils. Pelleted wheat bran carriers were very efficient in stimulating the growth of fungi in an industrial soil containing about 2800 mg kg^?1 PAHs. Fungal biomass and activity of extracellular laccases, enzymes produced by T. versicolor as markers of metabolic activity in the contaminated soil, both decreased after 2 weeks of incubation. Supplementing the soil with a mixture of carbon, nitrogen and phosphorus enhanced the fungal activity period. A 38% decrease of solvent extractable PAHs was observed in manufactured gas plant site soils when supplemented with T. versicolor, Glucidex 19^TM, ammonium nitrate, lime phosphate and Montanox 80^TM, after 20 weeks. Then, the degradation proceeded more slowly during the following 30 weeks, and reached 43% of initial extractable PAHs. Some factors governing a limited PAH biotransformation in the soil are discussed.