Strains Of White Rot Fungi Research Articles

Biogenic Degradation of Lignite Coal from Pakistani Coal Mine and Extraction of Humic Acid through Pretreatment Strategies by Fungal Isolate

The utilization of white rot fungal strain for degradation of low rank coal from coal environments is considered to be the best choice for converting raw coal into different kinds of valuable by products. NF-1, a fungal strain was isolated from coal mine of Thar region of Pakistan. For enhancing the process of biodegradation, the indigenous fungal isolate was used in the study. The lignite (low rank) coal sample degradation initiated by NF-1 strain were undergone through optimization process and had shown considerable production of organics at 1.5% Glucose, 1% coal loading ratio and 7 days of incubation period. The FTIR analysis of untreated coal and treated coal after solubilization was performed in order to observe changes in structural pattern by NF-1 fungal isolate. NF1 has the ability to break down the aromatic side linkages and attacking the amine and carboxyl groups. Scanning electron microscopy (SEM) of the coal treated by NF-1 strain was analyzed to investigate the attachment and adherence of the fungal mycelium on the coal surface. At 200µm the NF-1 isolate hyphae has clearly entrapped the coal particles showing erosion and up to 50µm colonization and visible changes on the coal surface can be observed clearly. Moreover, the residual coal after fungal pretreatment was processed for extraction of humic acid as a byproduct for defining the effect of such biological pretreatments. The produced humic acid was analyzed on the basis of E4/E6 ratio and FTIR. The fungal pretreated humic acid has shown more improvement in E4/E6 ratio as well as presence of functional groups related to humic acid through FTIR. This explains that the isolate NF1 have ability to speed up the biodegradation process and shows an aptitude of producing valuable by products i.e. humic acid as an alternative fuel.

Effective Decolorization and Detoxification of Single and Mixed Dyes with Crude Laccase Preparation from a White-Rot Fungus Strain Pleurotus eryngii.

To fully harness the potential of laccase in the efficient decolorization and detoxification of single and mixed dyes with diverse chemical structures, we carried out a systematic study on the decolorization and detoxification of single and mixed dyes using a crude laccase preparation obtained from a white-rot fungus strain, Pleurotus eryngii. The crude laccase preparation showed efficient decolorization of azo, anthraquinone, triphenylmethane, and indigo dyes, and the reaction rate constants followed the order Remazol Brilliant Blue R > Bromophenol blue > Indigo carmine > New Coccine > Reactive Blue 4 > Reactive Black 5 > Acid Orange 7 > Methyl green. This laccase preparation exhibited notable tolerance to SO42- salts such as MnSO4, MgSO4, ZnSO4, Na2SO4, K2SO4, and CdSO4 during the decolorization of various types of dyes, but was significantly inhibited by Cl- salts. Additionally, this laccase preparation demonstrated strong tolerance to some organic solvents such as glycerol, ethylene glycol, propanediol, and butanediol. The crude laccase preparation demonstrated the efficient decolorization of dye mixtures, including azo + azo, azo + anthraquinone, azo + triphenylmethane, anthraquinone + indigo, anthraquinone + triphenylmethane, and indigo + triphenylmethane dyes. The decolorization kinetics of mixed dyes provided preliminary insight into the interactions between dyes in the decolorization process of mixed dyes, and the underlying reasons and mechanisms were discussed. Importantly, the crude laccase from Pleurotus eryngii showed efficient repeated-batch decolorization of single-, two-, and four-dye mixtures. This crude laccase demonstrated high stability and reusability in repeated-batch decolorization. Furthermore, this crude laccase was efficient in the detoxification of different types of single dyes and mixed dyes containing different types of dyes, and the phytotoxicity of decolorized dyes (single and mixed dyes) was significantly reduced. The crude laccase efficiently eliminated phytotoxicity associated with single and mixed dyes. Consequently, the crude laccase from Pleurotus eryngii offers significant potential for practical applications in the efficient decolorization and management of single and mixed dye pollutants with different chemical structures.

Screening and Molecular Identification of Potential Lignolytic White Rot Fungi Isolated from Western Ghats

ABSTRACT: The mounting concerns over the usage of enormous amount of wood and perilous chemicals in paper industry have led the researchers to develop ecofriendly green technologies for pulp and paper production. Lignocellulosic agro-waste can be an excellent alternative to the wood in papermaking. White rot fungi with ligninolytic properties can be effectively used for pretreatment of agro-wastes for pulp making. This study isolates and identifies previously unexplored strains of white rot fungi from Western Ghats of Kerala, India which can be used for developing biological systems for lignocellulosic treatment in pulp and paper production. Ten isolates were identified using molecular techniques and screened for their extracellular enzyme activities, including laccase, Manganese peroxidase and Lignin peroxidase. Among the 10 isolates, Trametes versicolor (Laccase activity 31.79 U/ml, Manganese peroxidase (MnP) 42.336 U/ml and Lignin peroxidase (LiP) - 50.65U/ml, Favolus teniculus (Laccase - 41.54 U/ml, MnP - 44.07 U/ml &LiP - 30.54), Coriolopsis byrsina (Laccase - 42.56 U/ml, MnP - 43.54 U/ml and LiP - 25.14 U/ml) Lenzitus betulina (Laccase - 37.15 U/ml, MnP - 38.97 U/ml and LiP - 30.43 U/ml) exhibited highly promising lignolytic enzymatic system. The study’s findings may provide a better eco-friendly substitute for conventional chemical treatments in various industrial applications.

Studies on the degradation effect of corn straw by Asian corn borer larva (Ostrinia furnacalis) digestive enzymes combined with white rot fungus (Phanerochaetc chrysosporium).

The lignin, cellulose and hemicellulose contained in corn straw need to be degraded before reuse. Therefore, it is urgent to explore a new strategy that can enhance the degradation effect of lignin, cellulose and hemicellulose. Ostrinia furnacalis is one of the corn pests feeding on corn straw, which can degrade and consume corn straw by digestive enzyme secreted in the midgut. Herein, the degradation efficiency of lignin, cellulose and hemicellulose was tested by a stain of white rot fungus combined with digestive enzyme of O. furnacalis extracted from its midgut. It was proved that the selected strain of white rot fungus could degrade lignin, cellulose and hemicellulose effectively. The contents of lignin, cellulose and hemicellulose decreased with the extension of degradation time, with the lowest level reached at 35 d with 9ml digestive enzyme solution of O. furnacalis added. Compared with the control group, digestive enzyme of O. furnacalis could improve the degradation effect of the selected white rot fungi on lignin, cellulose and hemicellulose. The effect of degradation was enhanced with the extension of degradation time and the increase in the amount of digestive enzyme added. The results provide a new strategy and a basis for strengthening the degradation effect of white rot fungi on corn straw.

In vitro ruminal degradability of wheat straw cultivated with white-rot fungi adapted to mushroom farming conditions

Biological treatment of cereal straw for ruminant nutrition purposes might present an environmentally friendly option of valorizing a widely available by-product of grain production for farming systems with low external input. Several strains of white-rot fungi have been selected in the past under mostly controlled laboratory conditions for their capacity of lignin degradation. The study adapted to conditions on farm for upscaling purposes. The development of the in vitro straw digestibility with two different moistening pre-treatments and inoculated with three different fungi species, namely Pleurotus ostreatus, Ceriporiopsis subvermispora and Volvariella volvacea, was determined up to 42 days of fermentation with five sampling times. The effect of physical straw pre-treatments on nutritional parameters was evaluated. The neutral detergent fiber digestibility (NDFD30h), enzymatically soluble organic substance (ELOS) and the gas production (Hohenheim Feed value Test, HFT) as indicators for in vitro ruminal degradability decreased over time independent of the fungus: HFT, ELOS and NDFD30h by up to 50, 35 and 30% of the original straw. Remoistening and autoclaving the straw increased the gas production significantly by 2.6 mL/200 g dry matter (DM), and ELOS and NDFD30h by 45 and 51 g/kg DM compared to the original straw (34.9 mL/200 mg DM, 342 g/kg DM, 313 g/kg NDF).

Advances in Fungal Removal of Polycyclic Aromatic Hydrocarbons

Many studies on the bioremediation of PAHs-contaminated soils have shown that fungi are often more effective than bacteria for PAHs depletion. Fungi can survive better in contaminated environments because their mycelial growth can penetrate the soil layer and get close to the source of contamination, which can improve the bioavailability of soil organic pollutants; and have better tolerance to toxins. field et al reported in their study eight strains of white rot fungi that all had the ability to degrade PAHs, including strain Bjerkandera sp. BOS55 showed a 28-day removal rate of 99.2% and 83% for anthracene and benzo[a]pyrene, respectively.

Use of Anthracophyllum discolor and Stereum hirsutum as a Suitable Strategy for Delignification and Phenolic Removal of Olive Mill Solid Waste.

This study evaluated the use of the white-rot fungi (WRF) Anthracophyllum discolor and Stereum hirsutum as a biological pretreatment for olive mill solid mill waste (OMSW). The WRF strains proposed were added directly to OMSW. The assays consisted of determining the need to add supplementary nutrients, an exogenous carbon source or use agitation systems, and evaluating WRF growth, enzyme activity, phenolic compound removal and lignin degradation. The highest ligninolytic enzyme activity was found at day 10, reaching 176.7 U/L of manganese-independent peroxidase (MniP) produced by A. discolor, and the highest phenolic removal (more than 80% with both strains) was reached after 24 days of incubation. The confocal laser scanning microscopy analysis (CLSM) confirmed lignin degradation through the drop in lignin relative fluorescence units (RFU) from 3967 for untreated OMSW to 235 and 221 RFU, showing a lignin relative degradation of 94.1% and 94.4% after 24 days of treatment by A. discolor and S. hirsutum, respectively. The results demonstrate for the first time that A. discolor and S. hirsutum were able to degrade lignin and remove phenolic compounds from OMSW using this as the sole substrate without adding other nutrients or using agitation systems. This work indicates that it could be possible to design an in situ pretreatment of the valorization of OMSW, avoiding complex systems or transportation. In this sense, future research under non-sterile conditions is needed to evaluate the competition of WRF with other microorganisms present in the OMSW. The main drawbacks of this work are associated with both the low reaction time and the water addition. However, OMSW is seasonal waste produced in one season per year, being stored for a long time. In terms of water addition, the necessary optimization will be addressed in future research.

Solid-State Fermentation of Chestnut Shells and Effect of Explanatory Variables in Predictive Saccharification Models.

In this study, chestnut shells (CNS), a recalcitrant and low-value agro-industrial waste obtained during the peeling of Castanea sativa fruits, were subjected to solid-state fermentation by six white-rot fungal strains (Irpex lacteus, Ganoderma resinaceum, Phlebia rufa, Bjerkandera adusta and two Trametes isolates). After being fermented, CNS was subjected to hydrolysis by a commercial enzymatic mix to evaluate the effect of fermentation in saccharification yield. After 48 h hydrolysis with 10 CMCase U mL−1 enzymatic mix, CNS fermented with both Trametes strains was recorded with higher saccharification yield (around 253 mg g−1 fermented CNS), representing 25% w/w increase in reducing sugars as compared to non-fermented controls. To clarify the relationships and general mechanisms of fungal fermentation and its impacts on substrate saccharification, the effects of some independent or explanatory variables in the production of reducing sugars were estimated by general predictive saccharification models. The variables considered were lignocellulolytic activities in fungal fermentation, CNS hydrolysis time, and concentration of enzymatic hydrolysis mix. Multiple linear regression analysis revealed a very high significant effect (p < 0.0001) of fungal laccase and xylanase activities in the saccharification models, thus proving the key potential of these enzymes in CNS solid-state fermentation.

Evaluation of the capacity of laccase secretion of four novel isolated white-rot fungal strains in submerged fermentation with lignocellulosic biomass

The capacity of novel isolated white-rot fungi secreting laccase was evaluated for various kinds of lignocellulosic biomass in submerged fermentation. The laccase secreted by Neofomitella fumosipora Han 386 and Pleurotus pulmonarius Han 527 was significantly faster than that by Coriolopsis trogii Han 751 and Coriolopsis sanguinaria An 282. Maximum laccase from N. fumosipora Han 386 on the four kinds of lignocellulosic biomass tested appeared on the first day. This phenomenon indicated that N. fumosipora Han 386 secreted laccase rapidly compared with other tested strains in this study and showed the superiority in the rate of secreting laccase. Based on the maximum laccase activity, the ability of secreting laccase of C. sanguinaria An 282 was superior to other tested novel isolated strains. On the whole, N. fumosipora Han 386 and P. pulmonarius Han 527 preferred Toona sinensis to produce laccase, C. trogii Han 751 preferred to produce laccase on Populus beijingensis, and C. sanguinaria An 282 grown on Sorghum straw was more suitable for secreting laccase. The results will be helpful for developing bioprocesses using various kinds of lignocellulosic biomass for lignocellulolytic enzyme production and enlarging the number of laccase producing strains for industrial application.

Biodegradation of organophosphorus insecticide chlorpyrifos into a major fuel additive 2,4-bis(1,1 dimethylethyl) phenol using white-rot fungal strain Trametes hirsuta MTCC-1171

Biodegradation of chlorpyrifos, a widely used organophosphorus insecticide, was accomplished by using a white-rot fungal strain (Trametes hirsuta MTCC-1171). The experimental results showed that the fungal strain can effectively and rapidly degrade chlorpyrifos while using it as a sole source of carbon and energy when provided with mineral salt medium (MSM). The optimum experimental conditions for degradation of chlorpyrifos in liquid media can be summed as follows: initial pH 6.0; mycelial inoculum 0.18 ​± ​0.01 ​g ​L−1 (dry weight); chlorpyrifos concentration 150 ​mg ​L−1; pH 6.0; temperature 30 ​°C; and shaking speed 150 ​rpm. Under these optimal experimental parameters, T. hirsuta MTCC-1171 achieved ≥95% degradation of chlorpyrifos in 16 ​h of incubation. The degradation rate was quantified by employing HPLC followed by identification of degradation metabolites using gas chromatography–mass spectrometry (GC-MS). 2,4-Bis (1,1 dimethylethyl) phenol, a fuel additive, was found to be a major metabolite product of chlorpyrifos degradation. However, no metabolite bioaccumulation was observed in the process. Additionally, soil studies were carried out to investigate the degradation ability of the strain against chlorpyrifos, in a natural environment. During the assessment 37 ​± ​2.3% degradation was observed after 15 days of incubation. These results illustrate that T. hirsuta MTCC-1171 has a potential of using chlorpyrifos as a sole source of carbon. Besides, fundamental understanding gained through this work lays a foundation to investigate efficient and rapid bioremediation processes in agricultural and forest environments.

A novel peroxidase from white-rot Agaricomycetes fungus Phlebia radiata strain KB-DZ15: Its purification, characterisation, and potential application for dye-decolorisation and lignin-biodegradation

A novel extracellular lignin peroxidase (LiP) has been produced (65 U/mL) in potato dextrose broth (PDB)-optimized media by a white-rot Agaricomycetes fungus strain KB-DZ15 newly isolated from dead deciduous trees at Zimoula Forest (Tizi-Ouzou, Algeria). This strain was identified as Phlebia radiata based on internal transcribed spacer (ITS) rDNA gene sequencing. The peroxidase enzyme (called LiP PR40) was purified and characterised. The matrix-assisted laser desorption-ionization – time of flight mass spectrometry (MALDI-TOF/MS) analysis revealed that LiP PR40 enzyme was a monomer with a molecular mass of 40,125.31 Da. The 25 N-terminal residue sequence of LiP PR40 showed high similarity with those of fungi LiPs. Interestingly, LiP PR40 presents premium activity at pH 3 and 80 °C with specific activity and Reinheitzahl (RZ) level of 510 U/mg and 2.81, respectively. Furthermore, it was completely inhibited by sodium azide (NaN3) and potassium cyanide (KCN), suggesting the presence of haem components in its tertiary structure. More interestingly, LiP PR40 illustrated more upper catalytic efficiency and dye-decolorisation aptitude than that of commercial well-known horseradish peroxidase (HRP) from roots of Armoracia rustanica and the purified reported LiP BA45 from Bjerkandera adusta strain CX-9. Consequently, these properties make LiP PR40 a potential candidate for destaining synthetic-dyes and lignin-biodegradation.

Greener approach to substitute chemical reduction clearing process for fabric dyed with Foron Blue E-BL 150, Foron Rubine RD-GFL and Foron Brilliant Yellow S-6GL using indigenous resources

Abstract Fabric dyed with disperse dyes followed a reduction clearing process (RCP)/chemical clearing process (CCP) to remove the unfixed dye from the fabric. In the clearing process, unfixed dyes and chemicals are discharged into streams. To combat this issue, an environment friendly approaches is explored that is a biological clearing using indigenous fungal strains of white-rot fungi (Pleurotus ostreatus and Ganoderma lucidum). In this context, fabrics dyed with three disperse dyes (Foron Blue E-BL 150, Foron Rubine RD-GFL and Foron Brilliant Yellow S-6GL) were considered. The fabric cleared with biological clearing process improved the quality of fabric versus chemically cleared fabric and among the tested strains, G. lucidum showed higher efficiency for color strength improvement. However, no significant difference in tensile and tear strength of all fabric samples was observed. The quality of effluents in clearing reduction process for three dyes was assessed and it was observed that water quality parameters including chemical oxygen demand (COD), total organic carbon (TOC), biological oxygen demand (BOD), total suspended solids (TSS), pH, dissolved oxygen (DO) and total dissolved solids (TDS) improved significantly and results revealed that the biological clearing approach can substitute chemical reduction clearing process for fabric dyed with dyes, which is greener and eco-friendly versus conventional processes to avoid unfixed dyes discharge in to water bodies.

Characterization of a Novel Laccase LAC-Yang1 from White-Rot Fungus Pleurotus ostreatus Strain Yang1 with a Strong Ability to Degrade and Detoxify Chlorophenols.

In this study, a laccase LAC-Yang1 was successfully purified from a white-rot fungus strain Pleurotus ostreatus strain yang1 with high laccase activity. The enzymatic properties of LAC-Yang1 and its ability to degrade and detoxify chlorophenols such as 2,6-dichlorophenol and 2,3,6-trichlorophenol were systematically studied. LAC-Yang1 showed a strong tolerance to extremely acidic conditions and strong stability under strong alkaline conditions (pH 9–12). LAC-Yang1 also exhibited a strong tolerance to different inhibitors (EDTA, SDS), metal ions (Mn2+, Cu2+, Mg2+, Na+, K+, Zn2+, Al3+, Co2+, and metal ion mixtures), and organic solvents (glycerol, propylene glycol). LAC-Yang1 showed good stability in the presence of Mg2+, Mn2+, glycerol, and ethylene glycol. Our results reveal the strong degradation ability of this laccase for high concentrations of chlorophenols (especially 2,6-dichlorophenol) and chlorophenol mixtures (2,6-dichlorophenol + 2,3,6-trichlorophenol). LAC-Yang1 displayed a strong tolerance toward a variety of metal ions (Na2+, Zn2+, Mn2+, Mg2+, K+ and metal ion mixtures) and organic solvents (glycerol, ethylene glycol) in its degradation of 2,6-dichlorophenol and 2,3,6-trichlorophenol. The phytotoxicity of 2,6-dichlorophenol treated by LAC-Yang1 was significantly reduced or eliminated. LAC-Yang1 demonstrated a good detoxification effect on 2,6-dichlorophenol while degrading this compound. In conclusion, LAC-Yang1 purified from Pleurotus ostreatus has great application value and potential in environmental biotechnology, especially the efficient degradation and detoxification of chlorophenols.

The lignocellulolytic effect from newly wild white rot fungi isolated from Colombia

Lignocellulose is the most abundant natural polymer on earth. It is the main agro-industrial waste component, it has no added value, and in some cases is the main cause of environmental problems. The fungi can be used in the transformation of residues and different biotechnological processes. In the present research, seven strains of white rot fungi collected in Ibague (Colombia) were isolated. The production of ligninolytic and cellulolytic enzymes as well as their capacity to transform lignocellulose from banana peel, rice husk and cocoa pod husk were evaluated. Strains of Pycnoporus sanguineus, Hexagonia glabra and Lentinus crinitus were selected from the enzymatic screening and showed high production of ligninolytic enzymes. The evaluation of agricultural waste degradation was carried out by Fourier-transform infrared spectroscopy and the results showed the ability of the tested fungi to, preferentially, degrade lignin or cellulose in each substrate. Based on the results, different biotechnological potentialities for each strain were proposed.

Contribution of Lignin Peroxidase, Manganese Peroxidase, and Laccase in Lignite Degradation by Mixed White-Rot Fungi

The catalytic depolymerization of biological enzymes during biological liquefaction of coal is very important. In this study, the effects of medium types, lignite addition, and mixed culture on lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase (Lac) secreted by white-rot fungi are investigated. Fifteen strains of white-rot fungi are used for microbial liquefaction of the Zhaotong lignite in Yunnan. The results show that the activities of LiP, MnP, and Lac are highest in the Czapek-Dox medium (DOX), followed by the Sabouraud Maltose Broth (SMB) medium, and are almost zero in the Potato Dextrose Agar (PDA) medium. In the early stage of fungal growth, the medium contains sufficient nutrients, and lignite addition induces an inhibitory effect on extracellular enzyme secretion, whereas in the late growth stage characterized by nutrient deficiency, it exhibits an enhancing effect. For fungi pair combinations, if only single enzyme activity was considered, the positive synergistic effect of Lac in the mixed culture of s.commune and SL203 would be the highest, with the synergistic coefficient of 233.33. While three enzymes were considered, the integrated effects of ZTW07 and SL203 are the highest, with Lac, MnP, and LiP producing synergistic coefficients of 158.795, 1.217, and 1.006, respectively. It can be seen that the mixed culture can greatly improve the enzyme activity of white rot fungi and is one of the effective methods to improve the liquefaction efficiency.

Improving Biodegradation of Clofibric Acid by Trametes pubescens through the Design of Experimental Tools.

Clofibric acid (CLF) is the main pharmacologically active metabolite in composition of the pharmaceutical products used for controlling blood lipid content. This xenobiotic compound is highly persistent in the aquatic environment and passes unchanged or poorly transformed in wastewater treatment plants. A white-rot fungal strain of Trametes pubescens was previously selected, for its ability for clofibric acid biodegradation (up to 30%) during cultivation in submerged system under aerobic conditions at an initial CLF concentration of 15 mg L−1. Plackett-Burman design (PBD) and response surface methodology (RSM) were used for experimental planning, mathematical modelling and statistical analysis of data of the biotechnological process of CLF biotransformation by Trametes pubescens fungal strain. After optimization, the capacity of the selected Trametes pubescens strain to degrade CLF was increased by cultivation in a liquid medium containing 3 g·L−1 yeast extract, 15 g·L−1 peptone, 5 g·L−1 glucose and mineral salts, inoculated at 2% (v/v) vegetative inoculum and cultivated at pH 5.5, during 14 days at 25 °C and 135 rpm. In these optimized biotechnological conditions, the CLF biotransformation yield was 60%.

Pour une production contrôlée d’agarwood d’Aquilaria crassna Pierre ex Lecomte en Guyane : approches métagénomique, biochimique et histologique

Aquilaria Lam. est un genre d’arbre tropical de la famille des Thymelaeaceae dont le bois sain est de couleur blanche. Lorsque l’arbre est blessé, en interactions avec des micro-organismes environnementaux, l’arbre produit un bois transformé par sa forte teneur en composés secondaires : l’agarwood. L’agarwood, de couleur brun-noir, est particulièrement apprécié pour son odeur boisée intense. L’huile essentielle obtenue par hydrodistillation d’agarwood est très prisée en parfumerie. Ainsi, le marché mondial des produits dérivés d’Aquilaria est estimé, en 2018, à 11 milliards de dollars US. Face à la demande croissante sur le marché mondial, des agriculteurs guyanais ont réalisé des plantations expérimentales d’Aquilaria en Guyane. Ainsi, l’objectif du projet Aquil@Guyane est d’aider ces planteurs à produire une huile essentielle de composition chimique contrôlée, respectueuse de la biologie de l’arbre et de l’environnement. Dans ce contexte, le sujet de thèse a été orienté en vue de promouvoir la production de connaissances académiques de nature à contribuer au développement de la production d’agarwood d’Aquilaria crassna en Guyane. Après caractérisation des communautés fongiques présentes dans les arbres d’Aquilaria crassna en Guyane, permettant de révéler l’importance des Basidiomycètes dans la production d’agarwood, deux méthodes d’induction d’agarwood ont été comparées : une méthode d’induction par blessure, avec ou sans ajout de terre ; une méthode d’induction par inoculation de souches guyanaises sélectionnées de Basidiomycètes. Cette dernière méthode, notamment par inoculation de champignons de pourriture fibreuse, comme Pycnoporus sanguineus, est la plus performante pour obtenir un agarwood de qualité proche d’un agarwood de référence provenant du Laos. La spectrométrie proche infrarouge (SPIR) a été utilisée pour différencier le bois blanc et l’agarwood et pour distinguer différentes compositions chimiques d’agarwood. Les résultats obtenus sont cohérents avec ceux de l’analyse biochimique après hydrodistillation : l’utilisation de la SPIR pour trier et contrôler la qualité de l’agarwood avant son hydrodistillation est envisageable. Enfin, une méthode de culture de cals d’Aquilaria a été mise au point afin de comprendre, en laboratoire, les mécanismes moléculaires qui aboutissent à la production d’agarwood. Les résultats indiquent une production de terpènes par les cals d’Aquilaria contaminés par des souches de champignons de pourriture fibreuse.

High-potency white-rot fungal strains and duration of fermentation to optimize corn straw as ruminant feed

Five white-rot fungi Pleurotus ostreatus, Lentinus edodes, Hericium erinaceus, Pleurotus eryngii and Flammulina filiformis were studied (solid-state incubation and in vitro gas production) to determine lignin degradation and optimal duration of fermentation of corn straw. All fungi significantly decreased lignin, with optimal reductions after 28 d. Although cellulose also decreased, L. edodes and P. eryngii minimized these losses. In intro dry matter digestibility, total volatile fatty acid concentration and total gas production of fermented corn straw decreased (P < 0.001) as fermentation was prolonged, with improved rumen fermentability for all fungal treatments except F. filiformis. Total gas production in L. edodes did not decrease but peaked on day 28, whereas F. filiformis reduced methane emission. In conclusion, fermentation of corn straw with P. eryngii or L. edodes for 28 d degraded lignin and improved nutritional value as ruminant feed.

Combination of Biological and Hydrothermal Pretreatment of Mixed Rice Biomass for Fermentable Sugars Production

Rice biomass is one of the most staple agricultural by-products in Malaysia. In this study, mixed rice biomass (MRB) which combines rice husk and straw in certain ratio was used to produce the fermentable sugars. White-rot fungal strain, P.chrysosporium was used in biological pretreatment for 7 days (30°C). The pretreatment was proceeded by hydrothermal autohydrolysis for further removal of hemicellulose. The reducing sugar of soluble solid mixed rice biomass after autohydrolysis process was determined (0.225g sugar/g MRB). The characteristic of raw and insoluble solid pretreated MRB was observed by Scanning Electron Microscopy (SEM) and the functional groups changes were determined by Fourier Transformed Infrared (FTIR). The parameters of enzymatic saccharification were optimized using Central Composite Design for Response Surface Methodology by setting the concentration of commercial cellulase enzyme used, Celluclast 1.5L from 5 FPU/g to 15 FPU/g and incubation times from 24 to 72 hours. It was discovered that fermentable sugars production was increased from 0.098g sugar/g MRB (0.125 g/L) to 0.248g sugar/g MRB (0.319g/L) at optimized condition 82 hours incubation time and 10 FPU/g enzyme concentrations. Hence, the total reducing sugar produced was calculated as 0.473g sugar/g MRB and saccharification was determined as 66.31%.

Mycoremediation of high concentrations of polychlorinated biphenyls with Pleurotus sajor-caju LBM 105 as an effective and cheap treatment

Polychlorinated biphenyls (PCBs) are exceptionally stable organic pollutants. An effective and economically feasible process is essential for their removal. Mycoremediation using white-rot fungal strains proved as a highly effective approach that has not been thoroughly investigated. The aim of this work was to evaluate PCBs remediation efficacy applying Pleurotus sajor-caju LBM 105. Axenic cultures of the fungus, either in complex or N-limited liquid media, were spiked with 217 mg L−1 of a technical mixture of Aroclor 1242, 1254 y 1260 in oil transformer. PCBs removal capacity, toxicity reduction, changes in fungal morphology and laccase expression caused by pollutant addition and the cost-effectiveness of the remediation treatment were assessed when growing the fungus under two different nutritional conditions. P. sajor-caju LBM 105 could remove 97.7% and 91.7% of the PCBs mixture and reduced the toxicity in complex and mineral media respectively after 35 days of incubation. The addition of PCBs to P. sajor-caju LBM 105 culture media resulted in an increase in hyphal diameter, changes in biomass, glucose consumption, proteins and laccase secretion. A 3-fold rise in laccase activity was detected in both media at 28 day. Laccase mRNA augmented 16% and 91% at 21 and 28 days respectively when PCBs were added to the N-limited liquid media. Mycoremediation of PCBs with P. sajor-caju LBM 105 cultivated in N-limited liquid medium is an effective low-cost (0.69 $ g-1d-1) alternative technique for PCBs treatment.