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.

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.

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.

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.

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.

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%.

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.

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 .

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.

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.

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.

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.

响应面法优化白腐菌Pleurotus ostreatus降解六氯苯

采用响应面法优化白腐菌侧耳属菌株(Pleurotus ostreatus)降解六氯苯(HCB)的条件。结果表明,对HCB降解率影响显著性较大的是摇床转速和pH。在摇床转速125r/min、pH为7.0、培养温度为28℃、HCB初始质量浓度为10mg/L、接种量为5%(体积分数)、培养时间为2d的优化条件下,HCB降解率和降解速率分别为92.73%和2.318mg/(L.d)。

Pleurotus ostreatus BP连续开放预处理玉米秸秆的研究

通过筛选开放性菌株以及对开放状态下玉米秸秆糖化率随预处理时间变化规律的研究,建立了菌株Pleurotus ostreatus BP连续开放预处理玉米秸秆体系,并进一步对该体系的稳定性进行了评价。从14株自腐菌中筛选出5株在秸秆上萌发时间短、生长速率快的菌株,其中只有P.ostreatus BP能在玉米秸秆上开放培养,预处理15 d时糖化率最高。由此建立了P.ostreatus BP开放预处理玉米秸秆15 d的连续体系并预处理5批。结果表明,前3批的预处理效果较稳定,糖化率均比对照提高了20%以上。在连续的第4、5批次中,糖化率提高很少,这主要是由于开放体系中的杂菌数量急剧增多造成的。

白腐菌Pleurotus ostreatus漆酶的生产及其最佳诱导条件

漆酶可催化酚类化合物和芳香胺的氧化,在小分子介体物质存在下,漆酶氧化范围可进一步扩大。白腐菌Pleurotusostreatus3.42产漆酶能力强,可成为工业用漆酶的重要生产者。研究结果表明,其在静止培养条件下,菌体生长及产漆酶能力都优于摇床培养,同时限氮培养也利于漆酶的生产。在所选的碳氮源中,纤维素和酪蛋白为最佳碳氮源。在诱导剂中ABTS诱导效果最佳,添加后漆酶酶活可达1000U／mL。

东北林区土著白腐菌Pleurotus ostreatus产漆酶培养基的优化

为提高东北土著白腐真菌的产酶能力,采用摇瓶试验对采自东北林区的白腐真菌Pleurotus ostreatus的产漆酶培养基进行优化,并与目前普遍采用的TK培养基进行对比.结果表明:最佳碳源为玉米粉,质量浓度为8g/L;最佳氮源为氯化铵,质量浓度为0.88g/L.在最佳培养基条件下,白腐真菌Pleurotus ostreatus的漆酶活力和生物量分别达149.45U/L和0.0452g(干重)/L.对比优化后的培养基和目前普遍采用的TK培养基的产漆酶活性,结果表明优化的培养基产漆酶活性是TK培养基的3倍.运用SPSS统计软件对各影响因素进行了差异显著性检验,发现白腐真菌Pleurotus ostreatus产漆酶的主要影响因子为碳源类型.试验证明优化后的培养基能明显促进白腐真菌产漆酶,而选取适合的碳源类型则是配制培养基的关键.

Pleurotus ostreatus对直接耐晒翠蓝染料溶液脱色的研究

研究Pleurotus ostreatus(白腐真菌)对直接耐晒翠蓝GL染料溶液的脱色性能。结果表明,Pleurotus os-treatus能有效用于直接耐晒翠蓝染料溶液的脱色,pH值为5、温度为22℃左右脱色效果最佳;C溶液/C培养基>20%时,增大营养物浓度对脱色率无显著影响;Pleurotus ostreatu对GL的生物吸附符合Langmuir吸附模式,饱和吸附量为20mg/g(湿菌体);并可用Freundlich吸附模型表达,吸附动力学可用准二级速率方程描述;脱色是通过菌体吸附和菌酶降解双重机制实现的。

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.