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.

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.

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.

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.

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.

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.

镉胁迫下复合菌剂对大豆的光合修复及其固定化效果的探究

镉(cadmium,Cd)作为对大豆等粮食类作物毒害最大的重金属之一,不仅会抑制植物生长发育,还会损害其光合系统致使光合速率下降。目前对于镉修复技术的探讨多集中于施加植物激素、改变种植模式等方向,微生物与植物互作的研究仍有待探索。本研究为探究复合白腐真菌(White rot fungi)对镉污染的修复效果和固定化技术的实际应用价值,以4种白腐真菌和大豆作为供试材料,制备固态菌剂并对大豆设置土培处理,且模拟镉污染土壤的浓度为0、50、100 mg L^(-1),对应每个浓度分别进行3种处理(CK组-不做处理、EG1组-加入游离菌株、EG2组-加入固态菌剂),研究混菌发酵与固定化技术对菌株吸附效能的影响,同时探明镉毒害、固定化菌球以及大豆植株三者间的关联性。结果表明:(1)除黄孢原毛平革菌外,其余3种菌株兼容性良好。(2)当混菌菌株组别为凤尾:云芝等于1∶1时,处理浓度为50 mg L^(-1)的镉溶液时可达到87.33%的吸附率。(3)为延长混合菌株的使用时效,提高吸附效果,以海藻酸钠(SA)质量浓度为10 g L^(-1)、生物炭(BC)质量浓度为15 g L^(-1)、加菌量为2%制得的PVA固定化小球,在加入适量添加剂后96 h吸附率可达(95.12±1.68)%。(4)将固定化混菌菌剂施加入模拟镉污染土壤后,大豆的各项生长和光合指标受到的抑制作用均得到缓释,其中Fo的最大降幅为42.5%,Fv/Fm最大增幅为17.2%。(5)大豆的抗氧化系统在菌剂处理14 d时得到增强,CK组中SOD、POD、CAT 3种酶最高活性均得以提升,分别为27.34%、12.41%、13.58%;此外,Pro及MDA含量分别呈上升和下降趋势,共同表现出植物抗性的提高。综上,镉胁迫下植株的PSII光化学反应中心受到抑制,混合菌株固定化与单个或游离状态的菌株相比吸附效率更高,施加固态菌剂后可有效开启大豆的光保护机制,产生渗透调节物质,同时激活抗氧化系统,保证了大豆体内稳定的氧化还原环境以应对镉胁迫。

白腐真菌预处理农作物秸秆的研究进展

农作物秸秆资源丰富,对反刍动物来说是一种低成本的可再生粗饲料来源,但秸秆在饲喂动物时其高含量的木质纤维素限制了反刍动物瘤胃微生物的作用,以致不能被有效利用,在实际生产中缺乏理想的处理方式,没有开发出其应有的营养价值。白腐真菌预处理可以提高农作物秸秆的消化率,该菌能够在营养价值相对较低的秸秆上生长,可以通过分泌1种或多种木质纤维素降解酶以及自由基等,将木质纤维素分解为能够被反刍动物消化的糖类等小分子化合物。本文就农作物秸秆的饲料化应用现状、处理方式展开讨论,并对白腐真菌处理木质纤维素的作用机制和影响因素以及在动物生产上的应用进行了综述,旨在为提高农作物秸秆的营养价值提供理论参考。

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。

生物有机肥对土壤镉形态及玉米镉积累的影响

为探究生物有机肥治理镉污染土壤的可行性及对土壤重金属污染修复的效果,采集河南省淅川县2种镉污染土壤,分别设置6种施肥处理:CK(不施用任何物料)、NPK(常规施NPK肥)、NPK+0.5%OF(常规施肥+0.5%商品有机肥)、NPK+1%OF(NPK+1%商品有机肥)、NPK+0.5%BF(NPK+0.5%生物有机肥)和NPK+1%BF(NPK+1%生物有机肥),测定种植前后土壤全镉含量、土壤各化学形态镉、玉米植株根系及籽粒镉含量。结果显示,以添加1%生物有机肥的治理效果最佳,NPK+1%BF处理下2种土壤有效态镉含量相较于NPK+1%OF降幅分别为19.74%、7.09%;施用有机物料降低土壤弱酸提取态镉含量,提高残渣态镉含量,NPK+1.0%BF弱酸提取态镉含量相比CK下降11%、残渣态镉上升16%;施用有机物料各处理玉米植株根系、籽粒镉含量显著降低,以NPK+1.0%BF处理效果最佳,相比NPK处理,土壤Ⅰ的玉米根系、籽粒镉含量降幅达34.41%、31.59%。综上,在镉污染土壤中施用生物有机肥,可显著降低土壤有效态镉含量,促进土壤弱酸提取态镉向残渣态镉转化,降低镉危害;玉米根系及籽粒镉含量均显著下降,综合治理效果表现为生物有机肥优于商品有机肥。

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。

一株白腐真菌固体发酵产酶条件优化

目的:漆酶是一种含铜的多酚氧化酶,能催化多种酚类化合物和芳香族胺氧化物,在食品、造纸、能源、高分子化合物合成等领域有着广阔的应用前景。本研究以一株白腐真菌为研究对象,利用农作物秸杆为原料进行固体发酵,对其产漆酶条件进行优化,为更好利用这一真菌资源提供技术支持。方法:采用单因素实验,从发酵时间、料液比、温度、pH等四个方面对白腐真菌固体发酵产漆酶条件进行优化。结果:在培养基质为玉米芯与麸皮,接种量为10%、发酵时间为4 d、料液比为1∶2.5、发酵温度为28℃、pH 5.5时产漆酶活性最强,漆酶活性达98.99 U/g。结论:该白腐真菌具有较强的利用农作物秸杆产漆酶能力,可为其在农作物秸杆等生物质能源的综合利用提供理论依据。

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.

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.

白腐真菌Pleurotus ostreatus产羟基自由基及其对苯酚的降解研究

白腐真菌可通过醌(Quinone,简称Q)氧化还原循环产生羟基自由基(·OH)。本研究以Pleurotus ostreatus为供试白腐真菌并建立了醌氧化还原循环,通过单因素评价了醌种类、醌含量、菌丝量和Fe3+/EDTA对·OH产生速率和苯酚去除率的影响。结果表明当醌为2,6-二甲氧基-1,4-苯醌(DBQ)且其含量为600μM(在300~600μM范围),菌丝量为120 mg(在0~120 mg范围),Fe3+/EDTA为100/600(在100/700~100/300范围)时,·OH的产生速率和苯酚的去除效率均最高;同时发现·OH的产生速率越高,苯酚去除率也越高,由此推测在氧化还原循环中·OH的氧化作用是去除苯酚的主要原因。

Comparative Studies on Biodegradative Abilities of <i>Pleurotus ostreatus</i>and <i>P. pulmonarius</i>in Soils Contaminated with Crude and Used Engine Oils

Crude and used engine oil degrading ability of two white rot fungi Pleurotus ostreatus and P. pulmonarius were investigated for six months. One hundred grams of sterilized soil moistened with 75% distilled water (w/v) were weighed into 9 × 9 × 4 cm (350 cm3) jam bottles and mixed thoroughly with bonny light crude oil and used engine oil at different concentrations (0%, 5%, 10%, 15%, 25% and 30%), separately. Each bottle was then inoculated with two agar plugs of a vigorously grown mycelium of P. ostreatus and P. pulmonarius using a sterile cork borer. The bottles were incubated at room temperature for 6 months. The mycelia-ramified waste was separated from soils and analysed for physicochemical parameters such as organic matter, carbon, nitrogen, phosphorus, potassium, pH and total hydrocarbon content, (THC) after drying. The organic carbon, nitrogen and phosphorus contents in contaminated and inoculated soils were increased after six months. However, decrease in potassium, pH and THC occurred in these soils after the period of investigation. P. ostreatus reduced the initial THC to 8% and 9% in soils contaminated with 20% of crude and engine oils, respectively, which was lower than that of P. pulmonarius. The two white rot fungi could be exploited in bioremediation of soils contaminated with bonny light crude and used engine oils.

Sustainable Discoloration of Textile Chromo-Baths by Spent Mushroom Substrate from the Industrial Cultivation of Pleurotus ostreatus

Synthetic dyes are recalcitrant to degradation and toxic to different organisms. Physical-chemical treatments of textile wastewaters are not sustainable in terms of costs. Biological treatments can be more convenient and the lig-nin-degrading extracellular enzymatic battery of basidiomycetes are capable to discolor synthetic dyes. Many basidi-omycetes are edible mushrooms whose industrial production generates significant amount of spent mushroom substrate (SMS) with residual high levels of lignin-degrading extracellular enzymatic activities. We have demon-strated that the low cost organic substrate, the SMS deriving from the cultivation of the basidiomycetes Pleurotus ostreatus, is able to discolor anthraquinonic, diazo and monoazo-dyes when incubated in dying chromo-reactive and chromo-acid baths containing surfactants and anti-foams, where the concentrations of the different dyes are exceeding the one recovered in the corresponding wastewaters. Laccase was the lignin-degrading extracellular enzyme involved in the discolouring process. The exploitation of the low cost SMS in the treatment of textile wastewaters is proposed. Accordingly, a toxicological assessment, based on a cyto-toxicity test on a human amnion epithelial cell line (WISH) and the estimation of the germination index (GI%) of Lactuca sativa, Cucumis sativus and Sorghum bicolor, has been performed, showing the loss of toxicity of the chromo-baths after being discoloured by the SMS.