Memoria para optar al Título Profesional de Ingeniero de la Madera / Nothofagus obliqua (Mirb.) Oerst (roble o pellín), es una especie que se distribuye desde la Región de Valparaíso hasta la Región de Los Lagos; también habita en Argentina. Esta especie se caracteriza por la alta durabilidad natural que presenta su madera en individuos adultos. Sin embargo, para la madera proveniente de renovales, con diferentes características de color y densidad, no existen antecedentes sobre su comportamiento frente al ataque de hongos de pudrición u otros agentes de biodeterioro. Actualmente, la madera de renovales de roble es sometida a un tratamiento de “vaporizado”, el que tiene como objetivo igualar el color rosado a rojizo del duramen de la madera de renoval, con el rojo oscuro del duramen de roble pellín, mucho más apreciado en el mercado. Con el objetivo de proporcionar antecedentes sobre la durabilidad natural de la madera de renoval de roble y de la influencia del tratamiento de cambio de color (vaporizado), se evaluó la resistencia de estas maderas frente a la acción de hongos de pudrición mediante la pérdida de peso, solubilidad en soda y el % de lignina. Para realizar el estudio se utilizó madera de renoval de roble, empleándose 40 probetas de albura y 40 de duramen. Se aplicó el proceso de vaporizado a 20 probetas de cada grupo, de manera de compararlas con el comportamiento de la madera sin vaporizar frente al ataque del hongo de pudrición blanca Polystictus versicolor y de pudrición café Poria monticola, utilizando además, 20 probetas de roble adulto como testigo. La mitad de las probetas de cada conjunto fue evaluada a los 2 meses (T1) y el resto a los 4 meses (T2) desde el inicio del ataque fúngico. Los resultados indicaron que el vaporizado no tuvo influencia sobre la resistencia de la madera de renoval frente al ataque de P. versicolor, que generó el %PP más alto para todos los tipos de madera a los 2 meses de acción fúngica. Así mismo, el % de solubilidad en soda indicó que el hongo de pudricion blanca provocó el mayor biodeterioro en comparación con el hongo de pudricion café. Para el caso de P. monticola, se observó que el vaporizado tampoco tuvo efecto sobre la resistencia al ataque de pudrición, generándose el mayor biodeterioro a los 4 meses (T2) que a los 2 meses (T1). Esto señaló finalmente, que la madera de renoval de roble no es una madera durable, considerando su resistencia frente al ataque de hongos de pudrición. / Nothofagus obliqua (Mirb.) Oerst (roble o pellín), is a specie allocated from Valparaiso Region to Los Lagos Region, Chile, also it can be found in Argentina. This kind is characterised by its high natural durability of its wood in adults members. Nevertheless, there are not history, for wood from secondary forests, with different characteristics of color and density, about its behaviour against the fungal attack or other biodeterioration agents. Nowadays, the roble wood from secondary forests is subjected to a “steaming” treatment, which aims to equalize pink to reddish heartwood color of the wood from secondary forests, with the dark red of the roble pellin heartwood, much more appreciated in the market. In order to provide history about the natural durability of the roble secondary forest wood, and of the influence of the color change treatment (steaming), the resistance of these woods against the action of fungal through weightloss, soda solubility and the lignin percentage was evaluated. Roble wood (renoval) was used to carry out the research, using 40 test tubes for sapwood and 40 test tubes for heartwood. Steaming process was tested in 20 test tubes of each group to do the comparison with those samples that were not under the process but under the white rot fungi attack Polystictus versicolor and the brown fungi Poria monticola. Also 20 test tubes of old roble were used as reference sample. Half of the samples of each group was checked at two months (T1) and the remaining samples at four months (T2) since the attacks of fungi started. The results shown that the steaming did not affect the wood resistance against the attack of P. versicolor produced the highest %PP for all the samples at 2 months of the test. Moreover, the %S indicated that the white fungi produced a bigger biodeterioration than the brown one. In the case of P. Monticola, it was observed that the steaming had no effect neither about the resistance of fungal attack, generating the greatest deterioration at 4 months (T2) than 2 months (T1). This finally pointed that the roble secondary forest wood is not a durable one, considering its resistance against the fungal attack

M. Tech. Agriculture / Brown rot caused by Monilinia laxa is the main pre and postharvest disease of peaches; it affects the shelf life and marketability of peaches. Increasing consumer concern regarding food safety makes it necessary to search for natural environmentally friendly alternative products for postharvest disease control. The objective of this study is to develop an environmentally friendly essential oil technology for the control of brown rot (M. laxa) in peaches at postharvest stage to replace the currently used synthetic fungicide (Iprodione)

L’utilisation de matériaux d’origine végétale dans les bâtiments thermiquement performants pose la question de la pérennité des ouvrages principalement à cause de la dégradation fongique. Postia placenta est une espèce des champignons provoquant la pourriture brune, qui est la plus destructrice pour les constructions en bois.Ce travail se concentre sur l’observation et la modélisation de la croissance de Postia placenta à trois échelles successives : l'arborescence du mycélium (échelle discrète), la croissance en milieu libre (échelle continue) et la croissance en milieu encombré (échelle macroscopique). L’observation expérimentale de la croissance de Postia placenta utilise un microscope confocal à balayage laser pour quantifier les différentes mécanismes et obtenir les paramètres de croissance. A partir de cette observation, un modèle discret capable de générer un mycélium de forme extrêmement similaire à celle observée a été imaginé, développé et validé. Ensuite, à partir des profils de biomasse moyennés selon le rayon des mycéliums simulés par le modèle discret, un modèle continu basé sur une équation de réaction diffusion a été identifié pour décrire l’évolution de la concentration de biomasse fongique. Ce modèle continu offre la possibilité de la transition de l’échelle locale vers l’échelle macroscopique. Pour cela, des simulations de la prolifération en environnement encombré sont obtenues à l'aide du modèle continu. Par prise de moyenne, les champs spatio-temporels obtenus permettent de déterminer les paramètres d'un modèle continu similaire, mais valable à l'échelle macroscopique, sur un milieu fictif qui prend en considération la morphologie des obstacles. / The use of bio-based materials in thermally efficient buildings raises the question of the sustainability mainly due to fungal degradation. Among the wood-decay fungi, Postia placenta is one of the most common brown rot fungi, which are the most destructive due to their rapid decaying mechanisms. This work focused on the experimental observation and the modeling of fungal growth at three successive scales: the mycelial network (discrete scale), mycelial growth in homogeneous media (continuous scale) and mycelial growth in porous media (macroscopic scale).The experimental observation of the growth of Postia placenta was performed using confocal laser scanning microscopy to quantify the different growth mechanisms and obtain the growth parameters. A discrete model has been derived from this observation and is capable of generating mycelial networks extremely similar to the observed ones. A continuous formulation based on a reaction diffusion equation was developed from the radial biomass density of a mycelial network obtained in the discrete model. This continuous formulation was then used to derive an equivalent macroscale model able to account for fungal development in porous media. Simulations were performed on various periodic porous media. The parameters of the macroscale model was identified on the macroscopic fields obtained by averaging the local field over one periodic unit cell.

A number of fungi produce spalted wood, which is characterized by accumulation of black pigment in fine demarcation lines, often accompanied by discoloration or staining on the wood fibers. Specific spalting fungi were identified by molecular analysis. From a total of 19 isolates and 140 clones studied, 11 fungal species were identified. The two Chlorociboria species from North America were investigated and their anamorphs were unambiguously identified for the first time. Fungal pigment formation under the influence of moisture content and pH variation was investigated in sugar maple, American beech and agar inoculated with spalting fungi. Maximum pigment production occurred at treatment with pH 4.5 for sugar maple and beech inoculated with Trametes versicolor. Xylaria polymorpha produced external pigmentation in beech treated with buffer at pH 5 and sugar maple at pH 4.5. Fungal pigmentation by Trametes versicolor and Xylaria polymorpha was stimulated at low moisture content in both wood species tested. Melanin production by Inonotus hispidus and Polyporus squamosus was stimulated above 22-28% and 34-38% moisture content in beech and in sugar maple respectively. Fomes fomentarius and Polyporus brumalis produced maximum pigmentation in beech at 26 - 41% and in sugar maple at 59 - 96% moisture content. The variation of the moisture content and pH values of wood substrates can stimulate the intensity of pigmentation of specific fungi in wood. To investigate melanin synthesis from a variety of melanin precursors, experimental research on three spalting fungi tested their reaction to catechol and L-Dopa melanin precursors in wood and agar substrate. The results indicate multiple biosynthesis pathways for melanin assembly in Trametes versicolor, Xylaria polymorha and Inonotus hispidus, and catechol produced most pigmentation in all spalting fungi investigated. Microscopic analysis by light, fluorescence, electron and confocal microscopy also indicates a bi- or multi-modal activity of melanin production and assembly by several spalting fungi. Possible variations of melanin assembly were identified based on fungal and wood species. Immunofluorescence and immunogold labelling with Mab 6D2 melanin antibody confirmed the melanin nature of the pigments produced by Oxyporus populinus, Trametes versicolor, Xylaria polymorpha, Fomes fomentarius, and Inonotus hispidus.

A number of fungi produce spalted wood, which is characterized by accumulation of black pigment in fine demarcation lines, often accompanied by discoloration or staining on the wood fibers. Specific spalting fungi were identified by molecular analysis. From a total of 19 isolates and 140 clones studied, 11 fungal species were identified. The two Chlorociboria species from North America were investigated and their anamorphs were unambiguously identified for the first time. Fungal pigment formation under the influence of moisture content and pH variation was investigated in sugar maple, American beech and agar inoculated with spalting fungi. Maximum pigment production occurred at treatment with pH 4.5 for sugar maple and beech inoculated with Trametes versicolor. Xylaria polymorpha produced external pigmentation in beech treated with buffer at pH 5 and sugar maple at pH 4.5. Fungal pigmentation by Trametes versicolor and Xylaria polymorpha was stimulated at low moisture content in both wood species tested. Melanin production by Inonotus hispidus and Polyporus squamosus was stimulated above 22-28% and 34-38% moisture content in beech and in sugar maple respectively. Fomes fomentarius and Polyporus brumalis produced maximum pigmentation in beech at 26 - 41% and in sugar maple at 59 - 96% moisture content. The variation of the moisture content and pH values of wood substrates can stimulate the intensity of pigmentation of specific fungi in wood. To investigate melanin synthesis from a variety of melanin precursors, experimental research on three spalting fungi tested their reaction to catechol and L-Dopa melanin precursors in wood and agar substrate. The results indicate multiple biosynthesis pathways for melanin assembly in Trametes versicolor, Xylaria polymorha and Inonotus hispidus, and catechol produced most pigmentation in all spalting fungi investigated. Microscopic analysis by light, fluorescence, electron and confocal microscopy also indicates a bi- or multi-modal activity of melanin production and assembly by several spalting fungi. Possible variations of melanin assembly were identified based on fungal and wood species. Immunofluorescence and immunogold labelling with Mab 6D2 melanin antibody confirmed the melanin nature of the pigments produced by Oxyporus populinus, Trametes versicolor, Xylaria polymorpha, Fomes fomentarius, and Inonotus hispidus.

Τα υγρά απόβλητα ελαιοτριβείου (ΥΑΕ) παράγονται κατά την εξαγωγή του ελαιόλαδου από τα παραδοσιακά και τα φυγοκεντρικά ελαιοτριβεία τριών φάσεων. Τα ΥΑΕ έχουν διαφορετικά χαρακτηριστικά τα οποία εξαρτώνται από τη διαδικασία παραγωγής και τον τύπο των ελιών που χρησιμοποιούνται. Τα περισσότερα ελαιοτριβεία στην Ελλάδα χρησιμοποιούν την τριφασική διαδικασία εξαγωγής του ελαιόλαδου. Παρόλα αυτά, κάποια καινούρια χρησιμοποιούν τη διφασική διαδικασία εξαγωγής του ελαιολάδου. Παραδοσιακά ελαιοτριβεία συνεχίζουν να υπάρχουν, αλλά σε μικρότερη έκταση. Τα ΥΑΕ αποτελούν ένα σημαντικό πρόβλημα για την περιοχή της Μεσογείου, όπου παράγεται το 95 % της παγκόσμιας παραγωγής ελαιολάδου, εξαιτίας της υψηλής τους συγκέντρωσης σε χημικά απαιτούμενο οξυγόνο (ΧΑΟ) και της ικανότητάς τους να αντιστέκονται στη βιοαποδόμηση εξαιτίας της υψηλής τους περιεκτικότητας σε φαινολικές ενώσεις. Αυτές οι ενώσεις οφείλονται για το μαύρο χρώμα και τις φυτοτοξικές και αντιβακτηριδιακές ιδιότητες των ΥΑΕ. Διάφορες φυσικοχημικές μέθοδοι έχουν προταθεί για την επεξεργασία των ΥΑΕ, συμπεριλαμβανομένων της απλής συμπύκνωσης, της επίπλευσης και καθίζησης, της εξάτμισης και της χρήσης επιλεγμένων μεμβρανών, της ουδετεροποίησης με την προσθήκη H2SO4, της οξείδωσης με O3 και αντιδραστήριο Fenton, καθώς επίσης και την επαναχρησιμοποίηση των ΥΑΕ με διασκορπισμό σε αγροτικά εδάφη σαν λίπασμα. Σε ότι αφορά τις βιολογικές μεθόδους, οι αναερόβιες βιολογικές διεργασίες είναι ιδιαίτερα αποδοτικές εξαιτίας των γνωστών πλεονεκτημάτων που εμφανίζουν και σχετίζονται με την εξοικονόμηση ενέργειας και χημικών και της μικρής παραγωγής λάσπης, ειδικότερα όταν αφορά την επεξεργασία αποβλήτων με υψηλή συγκέντρωση ΧΑΟ. Η εποχιακή λειτουργία των ελαιοτριβείων (Νοέμβριος – Φεβρουάριος) δεν αποτελεί μειονέκτημα για τις αναερόβιες διεργασίες εξαιτίας των χαμηλών παρατηρούμενων ρυθμών αποδόμησης των μεθανογόνων μικροοργανισμών και της εύκολης επαναλειτουργίας των αναερόβιων χωνευτήρων μετά από αρκετούς μήνες μη λειτουργίας. Παρόλο που η αναερόβια χώνευση χρησιμοποιείται κατά κύριο λόγο για τη μείωση του υψηλού οργανικού φορτίου των ΥΑΕ, η παρουσία ενώσεων στα ΥΑΕ τοξικών προς τους μεθανογόνους φαίνεται να είναι ένα σημαντικό πρόβλημα για την αναερόβια επεξεργασία των ΥΑΕ. Μία προσέγγιση στο πρόβλημα θα ήταν η αραίωση του αποβλήτου ώστε να μειωθεί η συγκέντρωση των φαινολικών ενώσεων και των λιπαρών οξέων. Σε αυτή την περίπτωση εξετάζεται και η απομάκρυνση των στερών του αποβλήτου πριν την αναερόβια χώνευση. Μία δεύτερη προσέγγιση θα ήταν η εφαρμογή αερόβιας προεπεξεργασίας του αποβλήτου ώστε να απομακρυνθούν ενώσεις που είναι τοξικές για τα μεθανογόνα βακτήρια. Πιο συγκεκριμένα, ένα πρώτο στάδιο αερόβιας προεπεξεργασίας του ΥΑΕ με μύκητα λευκής σήψης, έχει προταθεί ως η πιο κατάλληλη μικροβιακή διεργασία προεπεξεργασίας για την επιλεκτική απομάκρυνση των φαινολικών. Στόχος της παρούσας διατριβής ήταν να μελετηθεί η ικανότητα του μύκητα λευκής σήψης Pleurotus ostreatus κάτω από άσηπτες ή μη συνθήκες να λειτουργήσει σε έναν καινοτόμο βιοαντιδραστήρα καθοδικής ροής και να διευρενηθεί η αποδοτικότητα εναλλακτικά της αραίωσης ή/και της προεπεξεργασίας στην αναερόβια χώνευση ΥΑΕ σε αναδευόμενο μεσόφιλο αντιδραστήρα. Επίσης, μελετήθηκε η αναερόβια χώνευση ΥΑΕ σε αντιδραστήρα τύπου ASBR και αντιδραστήρα PABR, αντίστοιχα. Μία καινοτόμος μέθοδος ακινητοποίησης των μυκήτων αποδείχτηκε κατάλληλη για την ανάπτυξη μιας αποδοτικής διεργασίας προεπεξεργασίας για την απομάκρυνση των φαινολικών. Η αναερόβια χώνευση είναι η πιο αποδοτική διεργασία για την επεξεργασία υγρών αποβλήτων ελαιοτριβείου. Παρόλα αυτά, αραίωση ή/και κάποιου τύπου προεπεξεργασία είναι απαραίτητη για την αποφυγή τοξικότητας των φαινολικών στους μεθανογόνους. Θερμική προεπεξεργασία ακολουθούμενη από καθίζηση ώστε να απομακρυνθεί το στερεό περιεχόμενο, από την άλλη, αποδείχτηκε ένας μη επιθυμητός τρόπος προεπεξεργασίας. Επιπλέον, αραιωμένο ΥΑΕ 1:1, χωρίς την απομάκρυνση των στερεών μπορεί να υποστεί επεξεργασία αποδοτικά σε υδραυλικό χρόνο παραμονής 30 ημέρες, εξασφαλίζοντας σταθερή παραγωγή βιοαερίου. Βιολογική προεπεξεργασία με μύκητα μπορεί να οδηγήσει σε σταθερή διεργασία σε υδραυλικό χρόνο παραμονής 30 ημέρες. Η αναερόβια επεξεργασία του αποβλήτου σε αντιδραστήρα ASBR είναι εφικτή με ισοδύναμο χρόνο παραμονής 30 ημερών χωρίς να αραιωθεί το απόβλητο. Η επεξεργασία σε αντιδραστήρα PABR είναι ωστόσο πιο αποδοτική εξαιτίας του σχεδόν κατά μία τάξη μεγέθους μικρότερο υδραυλικού χρόνου παραμονής (3.75 ημέρες), που αυτός μπορεί να λειτουργήσει και της μεγαλύτερης απόδοσης του σε βιοαέριο. Το αναερόβια επεξεργασμένο απόβλητο μπορεί να καταστεί κατάλληλο για διάθεση μετά από κατάλληλη επεξεργασία μεμβρανών (συνδυασμός υπερδιήθησης και αντίστροφης όσμωσης). / Olive mill wastewater (OMW) is produced during the extraction of oil from the olive fruit by the traditional mill and press process. ΟΜW has a wide range of characteristics depending on the type of the mill and the type of olive and equipment employed. Most of the mills in Greece use a 3-phase extraction process. However, some of the newer ones use the 2-phase extraction process. Traditional mills are still present but to a limited extent. OΜW treatment and disposal has become a critical environmental problem in the Mediterranean area that accounts for approximately 95% of the world olive oil production. This is because of its high organic chemical oxygen demand (COD) concentration, and because of its resistance to biodegradation due to its high content in phenolic compounds. These compounds are responsible for its dark color, and its phytotoxic and antibacterial properties. Various physico-chemical methods have been proposed for treating OMW, including simple evaporation, flotation and settling, vaporization and use of selected membranes, neutralization with addition of H2SO4, oxidation by O3 and Fenton reagent, as well as reuse of the OMW by spreading onto agricultural soil as an organic fertilizer. As far as biological processes are concerned, anaerobic biological processes are particularly suitable because of their well known advantages related to energy and chemicals saving and to the low production of sludge, especially when it comes to treatment of high COD wastewaters. The seasonal nature of the operation of olive mills (typically November to February) is not a disadvantage for anaerobic processes because the observed decay rates for methanogens are very low and a digester can be easily restarted following several months of shut-down. Although anaerobic digestion may be in principle used for reducing the high organic content of OMW, the presence of compounds toxic to methanogens in OMW appears to be a significant problem for the anaerobic digestion of OMW. One approach to the problem has been to sufficiently dilute the OMW to reduce the concentration of phenolics and fatty acids. In this case, the possibility of prior solids removal needs to be examined. A second approach has been the use of aerobic pretreatment of OMW to remove compounds that are toxic to methanogenic consortia. In particular, a preceding aerobic treatment of OMW with white-rot fungi, has been proposed as the most suitable microbial pretreatment process for the selective removal of phenolics. The aim of the present study was to study the ability of the white rot fungus Pleurotus ostreatus under aseptic or non aseptic conditions to function in a novel trickling filter immobilized fungi bioreactor and to investigate the feasibility of alternative dilution and/or pretreatment processes for the anaerobic digestion of olive-mill wastewater in a stirred tank mesophilic digester. The anaerobic digestion of OMW in an anaerobic sequencing batch reactor (ASBR) and in a periodic anaerobic baffled reactor (PABR) was also studied. A novel fungi immobilization method proved very suitable for the development of an efficient pretreatment process for phenolics removal. Anaerobic digestion is the most effective process for the treatment of olive mill wastewater. However, dilution and/or some type of pretreatment are necessary to avoid toxicity of the phenolics on the methanogens. Thermal pretreatment followed by sedimentation to remove the solids content, on the other hand proved to be an undesirable type of pretreatment. Diluted 1:1 raw OMW on the other hand, without any solids removal, can be effectively treated at an HRT of 30d, securing a stable high biogas yielding operation. Biological pre-treatment with fungi may lead to a stable process at an HRT of 30d. Anaerobic digestion of OMW using an ASBR (anaerobic sequencing batch reactor) is feasible at an equivalent HRT of 30d with the advantage that it can treat nondiluted wastewater. Treatment in a PABR, however, is much more effective as it requires an order-of –magnitude lower HRT ( 3.75 d) and yields large amounts of biogas. The anaerobically treated effluent is still not suitable for disposal. A membrane process such as reverse osmosis may be effectively used to render the anaerobically treated wastewater readily disposable.

La méthanisation de la biomasse lignocellulosique est un des moyens les plus efficients pour la production d’énergie renouvelable. Cependant, la lignine présente dans cette biomasse est difficile à hydrolyser. Cette limite peut être surmontée grâce aux prétraitements. Parmi eux, les prétraitements peu couteux par pourritures blanches sont attrayants mais ils ont été peu appliqués pour la digestion anaérobie. La présente étude explore les prétraitements par pourritures blanches de la paille de blé afin d’en améliorer sa méthanisation. Tout d’abord, une étape de sélection a révélé l’efficacité de la souche Polyporus brumalis BRFM 985 puisque 43% de méthane supplémentaire ont été obtenus par gramme de matières volatiles par comparaison avec la paille témoin. En prenant en compte les pertes de matières occasionnées par le prétraitement, cela correspondait à 21 % d’amélioration par gramme de matière sèche initiale. De plus, il a été montré que l’addition de glucose durant le prétraitement limitait la délignification et donc la production de méthane du substrat. Puis, des échantillons prétraités furent obtenus lors d’un plan d’expérience visant à optimiser le prétraitement par P. brumalis BRFM 985 ; les paramètres du prétraitement testés étaient : la durée et la température de culture, l’humidité initiale du substrat et l’addition de métaux. Les surfaces de réponse de la production de méthane à partir de ces échantillons furent construites. La production optimale de méthane ne fut pas atteinte dans le domaine expérimental testé mais l’impact positif de l’addition de métaux fut démontré, ainsi que l’importance de choisir une durée de culture adaptée. Ensuite, l’usage de la technique de la pyrolyse-GC-MS pour évaluer l’efficacité du prétraitement fut étudié. Une estimation de la quantité de biomasse fongique avec cette méthode apparaît possible. Le ratio polysaccharides/lignine déterminé par py-GC-MS a permis de classer des échantillons prétraités selon leur biodégradabilité anaérobie. La digestion anaérobie en voie sèche (DAVS) de paille de blé prétraitée en réacteur pilote fut menée en batch avec recirculation des lixiviats. Durant le démarrage de la DAVS, un trop fort S/I mène à une accumulation d’acides gras volatils (AGV) et parfois à la défaillance de la DAVS. Néanmoins, de forts S/I permettent de traiter plus de substrat et augmentent la production de méthane par volume de réacteur. Avec la paille de blé, des S/I entre 2 et 3 (en matières volatiles) permettent un bon démarrage de la DAVS. Alors qu’un ratio AGV totaux/alcalinité inférieur à 0,6 correspond à des réacteurs stables en digestion anaérobie voie liquide ; cette limite semble mal adaptée à la DAVS. Il fut observé que la DAVS pouvait récupérer d’une phase d’acidification tant que le ratio AGV totaux/alcalinité était inférieur à 2 et que la concentration en AGV était inférieure à 10 g/L dans les lixiviats. Malgré une amélioration de la biodégradabilité et une phase de démarrage facilitée, le prétraitement fongique non optimisé ne permit pas d’améliorer la production de méthane après prise en compte des pertes de matière occasionnées par le prétraitement. / Anaerobic digestion of lignocellulosic biomass is one of the most efficient ways to produce renewable energy. However, lignin contained in this biomass is difficult to hydrolyze. This limitation can be overcome by pretreatments. Among them, low-cost white-rot fungi pretreatments seem attractive but were scarcely applied for anaerobic digestion. The current study investigates white-rot fungi pretreatments of wheat straw to improve its methane production. Firstly, a selection step has revealed the efficiency of Polyporus brumalis BRFM 985 since 43% more methane per gram of pretreated volatile solids were obtained compared to the control straw. Taking into account the dry weight loss occurring during the pretreatment, it still corresponded to 21% more methane per gram of initial total solids. Moreover, glucose addition during the pretreatment was shown to limit delignification and thus methane production from the substrate. Secondly, pretreated samples were obtained in an experiment device aiming to optimize the pretreatment with P. brumalis BRFM 985; tested pretreatments parameters were: culture duration, temperature, initial substrate moisture content and metals addition. Response surfaces of methane production from those samples were built. Optimum methane production was not reached in the experimental domain but the positive impact of metals addition was demonstrated, so as the importance to choose adequate culture duration. Then, the use of pyrolysis-GC-MS technic to access pretreatment efficiency was studied. Estimation of fungal biomass amount on wheat straw with this method appeared possible. Polysaccharides/lignin ratio determined with py-GC-MS allowed to classify some pretreated samples according to their anaerobic degradability. Solid State Anaerobic Digestion (SSAD) of wheat straw pretreated in pilot-reactor was carried out in batch with leachate recycle. During SSAD start-up phase, too high Substrate/Inoculum (S/I) ratio leads to Volatile Fatty Acid (VFA) accumulation and sometimes to reactor failure but with high S/I more substrate can be treated and methane production per reactor volume increases. With wheat straw, S/I between 2 and 3 (Volatile Solid basis) allow a successful start-up in SSAD. Whereas Total VFA/alkalinity ratio under 0.6 corresponds to stable wet anaerobic digestion; this limit seems not well adapted to SSAD. It was observed that SSAD reactors were able to recover from acidification phase when Total VFA/alkalinity was lower than 2 and with VFA concentrations inferior to 10 g/L in leachate. Despite the improvement of biodegradability and the facilitation of start-up phase, non-optimized fungal pretreatment did not improve methane production after taking into account mass losses occurring during the pretreatment.

Made available in DSpace on 2015-03-26T13:51:43Z (GMT). No. of bitstreams: 1 01 - capa_abstract.pdf: 74835 bytes, checksum: 716f5bf894e92efbf5c4b42ff95351ad (MD5) Previous issue date: 2008-04-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The increase in world population demands ever more food and consumer goods, with a consequent increase in the production of agroindustrial residues natives from logging, alcohol fuel plants and industries for beneficiary eligibility of agricultural products. Several studies have demonstrated the potential of white rot fungi to decompose of lignocellulosic substrates, but the use of such residues in ruminant diets has not been properly examined. The objective of this study was to determine the chemical composition and in vitro digestibility of agroindustrial residues (eucalyptus bark, sawdust, sugarcane bagasse, corn kernels, coffee bark, coconut fiber and lump of cotton) inoculated with white rot fungi (Pleurotus ostreatus and Lentinula edodes), and determine the activity of cellulase, xylanase and laccase in ruminal fluid incubated in vitro with corn kernels or sugarcane bagasse ground at different particle sizes. When the residues were treated with L. edodes the content of CP in eucalyptus bark increased 91 % and 78 % in the treatments added with rice bran or urea, respectively. The content of ADL decreased 70% in fructified sawdust added with rice bran compared to the controls. The NDF of sugarcane bagasse decreased 5 % when added with rice bran and 21 % when added with urea. When the residues were treated with P. ostreatus the levels of CEL and ADL of eucalyptus bark decreased 22 % and 137 %, respectively. With sawdust, the concentrations of NDF and ADF decreased 19 % and 27 %, respectively, after fruit body formation. The EE increased 402 % in sugarcane bagasse treated with P. ostreatus. With corn kernels, the content of ash increased 130 % compared to controls in the treatment showing fruit body formation. There was a reduction of 60 % in the LDA content of coffee barks after fructification. Fungus fructification in the coconut fiber reduced the levels of LDA and CEL in 25 % and 20 %, respectively. There were no significant differences between treatments for CP, ADF, CEL, HEM and ADL contents in the lump of cotton. However, there was significant difference in IVDMD between the enriched fructified substrates treated with L. edodes. An average increase 111 % and 98 % was observed for the fructified fungus added with rice bran or urea, respectively, compared to controls. The biggest increase in IVDMD after fructification in residues treated with P. ostreatus was obtained for the eucalyptus bark (200 %), followed by corn kernels (67 %) and sugar cane bagasse (13 %). The highest cellulase activity in corn kernels residues was obtained when using particles with a diameter of 0.6 mm. The xylanase activity was higher than the activity of cellulase for all treatments and sizes of particles tested. The particle size of 0.6 mm in the inoculated treatment yielded maximum xylanase activity after 48 hours of incubation (118.17 U/mL). The activity of cellulase in sugarcane bagasse was superior for all treatments and particle sizes when compared to corn kernels residues. The highest activity of xylanase (78.89 U/mL) in the fructified sugarcane bagasse was obtained after 48 hours of incubation and particles size of 0.6 mm. The changes in chemical composition and IVDMD showed that L. edodes (UFV 73) and P. ostreatus (PLO 06) could improve the nutritional quality of ruminant rations by increasing the content of CP and IVDMD and reducing the levels of NDF, ADF and ADL of agroindustrial residues, allowing its use in ruminant rations. / O aumento da população mundial demanda cada vez mais alimentos e bens de consumo, com conseqüente aumento na produção de resíduos agroindustriais oriundos de madeireiras, usinas de álcool combustível e indústrias de beneficiamento de produtos agrícolas. Diversos estudos têm demonstrado o potencial de fungos da podridão branca em decompor substratos ligninocelulósicos, mas a utilização desses resíduos na alimentação de ruminantes ainda tem sido pouco explorada. O objetivo deste trabalho foi determinar a composição bromatológica e a digestibilidade in vitro de resíduos agroindustriais (casca de eucalipto, serragem de eucalipto, bagaço de cana-de-açúcar, sabugo de milho, casca de café, fibra de coco e casca de caroço de algodão desengordurado) inoculados com fungos causadores da podridão branca (Pleurotus ostreatus e Lentinula edodes), assim como determinar a atividade enzimática de celulase, xilanase e lacase em três diferentes tamanhos de partículas dos resíduos sabugo de milho e bagaço de cana-de-açúcar incubados com líquido ruminal in vitro, visando avaliar o potencial hidrolítico das comunidades microbianas do rúmen. Quando os resíduos foram tratados com L. edodes o teor de PB do resíduo casca de eucalipto aumentou 91 % e 78 % no tratamento enriquecido com farelo de arroz e uréia, respectivamente. O teor de LDA diminuiu 70 % na serragem de eucalipto frutificada e enriquecida com farelo de arroz comparada ao controle. A FDN do resíduo bagaço de cana diminuiu 5 % quando enriquecido com farelo e 21 % quando enriquecido com uréia. Quando os resíduos foram tratados com P. ostreatus os teores de CEL e LDA da casca de eucalipto diminuíram 22 % e 137 %, respectivamente, após o tratamento. Na serragem de eucalipto as concentrações de FDN e FDA diminuíram 19 % e 27 % no tratamento frutificado, respectivamente. O EE aumentou 402 % no tratamento frutificado no bagaço. No sabugo o conteúdo de cinzas aumentou 130 % no tratamento frutificado em relação ao controle. Houve redução de 60 % no teor de LDA da casca de café após a frutificação. A frutificação fúngica reduziu os teores de LDA e CEL em 25 % e 20 %, respectivamente na fibra de coco. Não houve diferenças significativas entre os tratamentos para os teores de PB, FDA, CEL, HEM e LDA no resíduo casca de caroço de algodão desengordurado. Houve diferença significativa na DIVMS entre os enriquecimentos dos resíduos tratados com L. edodes, tendo sido observado aumento médio de 111 % e 98 % quando frutificado e adicionado de farelo de arroz e uréia, respectivamente, em relação ao controle O maior incremento de DIVMS no tratamento frutificado nos resíduos tratados com P. ostreatus foi obtido para a casca de eucalipto (200 %), sabugo de milho (67 %) e bagaço de cana-de-açúcar (13 %). As maiores atividades de celulase no resíduo sabugo de milho foram obtidas quando se utilizou partículas com 0,6 mm de diâmetro. A atividade de xilanase foi maior quando comparada à atividade de celulase em todos os tratamentos e tamanhos de partículas testados. O tamanho de partícula 0,6 mm no tratamento inoculado foi o que apresentou atividade máxima de xilanase após 48 horas de incubação (118,17 U/mL). A atividade de celulase no resíduo bagaço de cana-de-açúcar foi superior em todos os tratamentos e tamanhos de partículas quando comparado ao resíduo sabugo de milho. O tamanho de partícula 0,6 mm apresentou as maiores concentrações de xilanase no bagaço de cana-de-açúcar, tendo sido observado valor máximo após 48 horas de incubação de 78,89 U/mL no tratamento frutificado. As mudanças na composição química e na DIVMS indicam que L. edodes (UFV 73) e P. ostreatus (PLO 06) melhoram o valor nutricional dos resíduos tratados, aumentando o teor de PB e DIVMS e reduzindo os teores de FDN, FDA e LDA dos resíduos agroindustriais, com possibilidade de utilização na alimentação de ruminantes.

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The remediation of persistent chlorinated aromatic compounds has become a priority of great relevance due to the teratogenic, carcinogenic and endocrine-disrupting properties of these xenobiotics. The use of biological methodologies for the clean-up of contaminated sites, collectively referred to as "bioremediation", has been gaining an increasing interest in recent years because it represents an effective, cost-competitive and environmentally friendly alternative to the physico-chemical and thermal treatments. In this respect, "white rot" fungi, an ecological subgroup of filamentous fungi, display features that make them excellent candidates to design an effective remediation technology ("mycoremediation"). In spite of this, fungi have not been widely exploited for their metabolic capabilities and the mechanism by which they are able to degrade the aforementioned pollutants has not been fully elucidated yet. Within this frame, the present Ph.D thesis was aimed at: i) assessing the efficiency of different mycoremediation strategies for the clean-up of a polychlorinated biphenyl (PCBs)-contaminated soil; ii) understanding the fungal degradation pathways of polychlorinated biphenyls and their major metabolites, namely chlorobenzoic acids (CBAs) and hydroxylated polychlorinated biphenyls (OH-PCBs). i)...