Spelling suggestions: "subject:"laccase."" "subject:"accase.""
131 |
Aprimoramento de biossensor de lacase para determinação de micropoluentes fenólicos em águas contaminadas / Laccase biosenseor enhancement for determination of contaminated water in micropollutants phenolicsRibeiro Júnior, Eli José Miranda 30 January 2015 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-23T12:13:09Z
No. of bitstreams: 2
Dissertação - Eli José Miranda Ribeiro Júnior - 2015.pdf: 709119 bytes, checksum: baa5cef4451e6bd53886e3cc249f19df (MD5)
license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-10-23T12:15:43Z (GMT) No. of bitstreams: 2
Dissertação - Eli José Miranda Ribeiro Júnior - 2015.pdf: 709119 bytes, checksum: baa5cef4451e6bd53886e3cc249f19df (MD5)
license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-10-23T12:15:43Z (GMT). No. of bitstreams: 2
Dissertação - Eli José Miranda Ribeiro Júnior - 2015.pdf: 709119 bytes, checksum: baa5cef4451e6bd53886e3cc249f19df (MD5)
license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5)
Previous issue date: 2015-01-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Laccase is a poliphenoloxidase enzyme that catalyzes the oxidation of phenolic compounds in the corresponding quinones. The current obtained in this redox process can be used for quantitative analysis. In this work, a carbon paste biosensor modified gluteraldehyde functionalized silica and an enzymatic extract of the “Pycnoporus sanguineus” fungi as a lacase source is proposed for phenol determination. The effect of carbon paste and electrolyte composition, pH from 3,0 to 8,0, start potential from 0,55 to 0,25mV, scan rate from 5 to 25 mV s-1 and potential pulse amplitude from 10 to 60mV on the differential pulse voltammetric response was investigated. A linear correlation of R² = 0,9946 was obtained for the phenol content (catechol) in the concentration range from 50 to 500nMol L-1, with a detection limit of 30nMol L-1. This biosensor was used for the determination of different kinds of phenolic compounds, presenting a better response for catechol. / A lacase é uma enzima poliphenoloxidase que catalisa a oxidação de compostos fenólicos nas correspondentes quinonas. A corrente obtida neste processo redox pode ser usada para a análise quantitativa da concentração dos fenóis na água. Neste trabalho, é proposto o uso de um biossensor modificado para a determinação de fenol. O biossensor de pasta de carbono com sílica funcionalizada foi modificado com glutaraldeído e um extrato enzimático de fungos “Pycnoporus sanguineus” como uma fonte de lacase. O efeito da pasta de carbono e da composição de electrólito, permite trabalhar com pH compreendido entre 3,0 - 8,0, e um potencial inicial entre 0,55 - 0,25mV. A velocidade de varrimento foi de 5 a 25mV s-1 e amplitude de pulso de 10 a 60mV, estudando-se na resposta voltamétrica de pulso diferencial .Uma correlação linear de R2 = 0,9946 foi obtida para o teor de fenol (catecol) na gama de concentrações de 50 a 500nMol L-1, com um limite de detecção de 30nMol L-1. Este biossensor foi utilizado para a determinação de diferentes tipos de compostos fenólicos, apresentando uma melhor resposta para o catecol.
|
132 |
Remediação bio-eletroquímica do hormônio sexual sintético 17-α-etinilestradiol / Bio-electrochemical remediation of synthetic sex hormone 17-a- ethinylestradiolGarcia, Luane Ferreira 28 March 2016 (has links)
Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2016-06-08T18:45:11Z
No. of bitstreams: 2
Dissertação - Luane Ferreira Garcia - 2016.pdf: 1247655 bytes, checksum: 7639a387a5a3d1f4157419202b05240e (MD5)
license_rdf: 19874 bytes, checksum: 38cb62ef53e6f513db2fb7e337df6485 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-06-09T11:35:52Z (GMT) No. of bitstreams: 2
Dissertação - Luane Ferreira Garcia - 2016.pdf: 1247655 bytes, checksum: 7639a387a5a3d1f4157419202b05240e (MD5)
license_rdf: 19874 bytes, checksum: 38cb62ef53e6f513db2fb7e337df6485 (MD5) / Made available in DSpace on 2016-06-09T11:35:52Z (GMT). No. of bitstreams: 2
Dissertação - Luane Ferreira Garcia - 2016.pdf: 1247655 bytes, checksum: 7639a387a5a3d1f4157419202b05240e (MD5)
license_rdf: 19874 bytes, checksum: 38cb62ef53e6f513db2fb7e337df6485 (MD5)
Previous issue date: 2016-03-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Hormones are released constantly in sewage, originated by of human/animal excreta, or waste of pharmaceutical industries, not treated satisfactorily. The eviction of these pollutants in water resources produces great environmental impact, as disruption in animals’ endocrine system. The 17α-ethinylestradiol (EE2) is the most popular synthetic estrogen, which is found in water and in considerable concentrations. Several strategies are being studied to remedy this pollutant. Enzymes as laccases, which have low specificity, are able to oxidize various pollutants, thus suggesting their potential in the treatment of effluents. Another alternative are the electrochemical processes as electro-oxidation and electrocoagulation. The aim of this study was to evaluate the removal efficiency of the EE2 for biological or/and electrochemical process. The crude extract containing the laccase from Pycnoporus sanguineus was immobilized in Ca/Cu-alginate-chitosan beads. For partial characterization were determined optimum pH and optimum temperature of enzyme activity, for free and immobilized enzyme. Biological remediation was performed in these conditions: shaking (100 rpm); temperature at 28°C (± 2); times of 4, 8 and 24 hours; EE2 solution buffered at pH 4 and 5, and EE2 solution without addition of buffer. For the electrochemical remediation: magnetic stirring; voltage of 2.5, 5 and 7.5 V; times of 10, 20 and 40 minutes; pHs 5 and 7. For bio-electrochemical remediation the best conditions were used. In the remediation assays of the EE2 with immobilized enzyme, the best result was obtained for the support Ca-alginate-chitosan with 89.81% (± 2.71) removal, in sodium acetate buffer pH 5.0 and 24 hours of treatment. Under the same conditions to the free enzyme, 91.81% (± 0.86) of removal was obtained. For electrochemical remediation with titanium electrode, 86.21% (± 9.30) was removed in pH 7 phosphate buffer and 40 minutes. For sequential bio-electrochemical remediation, EE2 concentrations were below the limit of detection of the chromatograph, with the removal by immobilized enzyme acting in unbuffered solution. It can be concluded that the two technologies are very effective for the removal of the EE2. / Hormônios são lançados constantemente em esgotos, sejam oriundos de excretas humanas ou animais, sejam de resíduos provenientes das indústrias farmacêuticas, não tratados de forma eficaz. O despejo destes micropoluentes nos recursos hídricos produz grande impacto ambiental, como desregulação do sistema endócrino em animais. O 17α-etinilestradiol (EE2) é o mais popular estrogênio sintético, sendo encontrado nos recursos hídricos em concentrações consideráveis. Diversas estratégias estão sendo estudadas para remediação deste poluente. Enzimas como as lacases, que possuem baixa especificidade, são capazes de oxidar diversos poluentes, sugerindo assim seu potencial no tratamento de efluentes. Outra alternativa são os processos eletroquímicos, como a eletro-oxidação e eletrocoagulação. Sendo assim, o objetivo deste trabalho foi avaliar a eficiência de remoção do EE2 por processo biológico ou/e eletroquímico. O extrato bruto contendo a lacase de Pycnoporus sanguineus foi imobilizado em beads de quitosana-alginato-Ca/Cu. Para caracterização parcial da enzima livre e imobilizada foram determinados pH e temperatura ótima de atividade enzimática. A remediação biológica foi realizada nas condições: agitação (100 rpm); temperatura em 28°C (± 2); tempos de 4, 8 e 24 horas; solução de EE2 tamponada em pHs 4 e 5, e solução do hormônio sem adição de tampão. A remediação eletroquímica: agitação magnética; tensão de 2,5, 5 e 7,5 V; tempos de 10, 20 e 40 minutos; solução de EE2 tamponada em pHs 5 e 7. Para remediação bio-eletroquímica, de modo sequencial, foram utilizadas as condições mais adequadas para ambas as tecnologias. Nos ensaios de remediação do hormônio EE2 com a enzima imobilizada, o melhor resultado foi obtido para beads de quitosana-alginato-Ca com remoção de 89,81% (± 2,71) em tampão acetato de sódio pH 5 e 24 horas de tratamento. Nas mesmas condições, para a enzima livre foi obtido 91,81% (± 0,86) de remoção. Para remediação eletroquímica, com eletrodo de titânio foi removido 86,21% (± 9,30) do EE2, em tampão fosfato pH 7 e 40 minutos. Para a remediação bio-eletroquímica em modo sequencial, obteve-se remoção do EE2 em concentrações abaixo do limite de detecção do cromatógrafo, com a enzima imobilizada atuando em solução não tamponada. Conclui-se que as duas tecnologias são bastante eficientes para a remoção do EE2, podendo ser utilizadas separadamente ou em conjunto.
|
133 |
Biodegradace polychlorovaných bifenylů pomocí ligninolytických hub a jejich enzymů / Biodegradation of polychlorinated biphenyls by white - rot fungi and their enzymesLinhartová, Lucie January 2010 (has links)
Polychlorinated biphenyls (PCB) represent relevant persistent organopollutants of the environment and the estimated amount of PCB released into the environment is 750000 metric tons. White-rot fungi have been studied for long time due to their degradative potential toward various aromatic pollutants and it is known that these fungi are able to decompose PCB in vivo. Biodegradation of PCB by the fungus Pleurotus ostreatus was studied in the frame of this work. A high degradative efficiency of P. ostreatus was observed in the first set of experiments, even in the presence of relative high amount of added PCB. Fungus was able to transform 780±50 µg out of the intial amount 1000 µg in 20 ml of a cultivation media within 42 days. A decrease in toxicity was recorded during the degradation that suggests the suitability of this organism for a practical use in decontamination. In vitro experiments with purified laccase induced with Cu2+ from this fungus did not prove any participation of the enzyme in the first step of PCB transformation. The enzyme did not show an ability to degrade PCB even after purification from cultivation media containing PCB. It was found that the first step of PCB transformation can be performed by an intracellular process with microsomal fraction. A degradation of 44-67% was observed for...
|
134 |
Studium interakce houby Pleurotus ostreatus a bakteriálních kultur na abiotickém nosiči - morfologická, biochemická a proteomická analýza / Study of the interaction between fungus Pleurotus ostreatus and bacterial cultures on the abiotic surfaces - morphological, biochemical and proteomic analysisKozická, Barbora January 2015 (has links)
Ligninolytic fungi are well known for their ability to degrade a wide range of xenobiotics contaminating the environment, including synthetic industrial dyes. In this work Pleurotus ostreatus was used for decolorization of a synthetic textile dye Remazol Brilliant Blue R (RBBR). To set up a model fungal "fixed-bed" bioreactor the fungus was immobilized on a polyurethane foam and artificially contaminated with a model bacterium Rhodococcus erythropolis. The development of bacterial contamination can be expected during a real application of fungal bio filters in wastewater treatment. The main aim of the work was to study interspecies interactions in the model bioreactors during the dye decolorization. Ligninolytic enzyme activities were followed in the bioreactor cultures as markers of fungal biodegradation ability. In contrast to the controls, no bacterial growth was observed in the P. ostreatus bioreactor culture liquid. The results showed that fungal laccase, pH of the culture liquid, and glucose consumption by the fungus had no effect on the bacterial growth. However, 4*105 - 1,3*106 CFU/ml of R. erythropolis was detected to be associated with the fungal solid support. The presence of these bacteria had no effect on the decolorization performance of the bioreactors. Dye decolorization efficiency...
|
135 |
Développement de papier bioactif par couchage à grande échelle d’enzymes immobilisées par microencapsulationGuerrero Palacios, Marco Polo 08 1900 (has links)
No description available.
|
136 |
Auswirkungen der pilzlichen Artengemeinschaft sowie ausgewählter Pilzenzyme und physikochemischer Totholzparameter auf die Zersetzung von 13 Baumarten im Nationalpark Hainich-DünLeonhardt, Sabrina 16 June 2020 (has links)
Totholz ist als wichtiges Strukturelement in Waldökosystemen und von zentraler Bedeutung für deren Funktion. Es dient zahlreichen Organismen als Lebensraum oder Substrat und ist wichtiger Bestandteil des Kohlenstoff- und Nährstoffkreislaufes. Um Totholz effizient zu zersetzen, haben saprobionte Pilze aus den Phyla der Basidiomycota und Ascomycota verschiedene ökologische und physiologische Strategien entwickelt. Die bedeutendste Rolle im Totholzabbau spielen dabei Weißfäulepilze. Sie sind in der Lage, mit ihren extrazellulären oxidativen Enzymen, wie Laccasen und verschiedenen Peroxidasen, Lignin anzugreifen, chemisch zu modifizieren und abzubauen. Über den Abbauprozess im natürlichen Totholz durch lignocellulolytische Enzyme und deren dazugehörige Pilzgemeinschaft sowie über Faktoren, die zusätzlich Einfluss auf Abbauprozesse nehmen können, ist wenig bekannt. Das Ziel dieser Arbeit innerhalb des BELongDead-Projekts (als Teil der Biodiversitäts-Exploratorien) war es deshalb, den pilzlichen Abbau von Totholz in der fortgeschrittenen initialen Phase (nach ca. sechs Jahren) des Zersetzungsprozesses zu betrachten. Weiter sollte die Rolle der lignocellulolytischen Enzyme beschrieben und ihre Abhängigkeiten von verschiedenen physikalisch-chemischen Totholzvariablen aufgezeigt werden. Darüber hinaus sollte geklärt werden, welchen Einfluss die Zusammensetzung der pilzlichen Gemeinschaft auf den Totholzabbau hat und welche Arten sowie Ökotypen dominieren. Hierfür wurden natürliche Totholzstämme 13 verschiedener heimischer Baumarten (Acer sp., Betula sp., Carpinus betulus, Fagus sylvatica, Fraxinus excelsior, Larix decidua, Picea abies, Pinus sylvestris, Populus sp., Prunus avium, Pseudotsuga menziesii, Quercus sp. und Tilia sp.) im Nationalpark Hainich-Dün (Thüringen) untersucht. Zusätzlich erfolgte die getrennte Betrachtung der pilzlichen Abbauprozesse im Splint- und Kernholz. Insgesamt wurden 82 Totholzproben entnommen und darin die Aktivitäten der Lignin-modifizierenden Enzyme (Laccase/Lac, Generelle Peroxidase/GenP, Mangan-Peroxidase/MnP) und verschiedener (hemi)cellulolytischer Enzyme gemessen. Zudem wurden Enzyme, die im Stickstoff-, Phosphor- und Schwefelkreislauf eine Rolle spielen, betrachtet. Des Weiteren wurden Totholzvariablen wie Pilzbiomasse, pH-Wert, Wassergehalt, wasserlösliche Ligninfragmente, die Gehalte an Lignin und Extraktiven sowie an Nährstoffen (C, N, C:N) und Metallen (Ca, Cu, K, Mg, Mn und Zn) ermittelt. Die pilzliche Gemeinschaftsstruktur und Artenzahl wurde mit Hilfe einer Next Generation Sequencing Methode (Illumina MiSeq) erfasst.
Aufgrund der physikalischen und chemischen Eigenschaften des Holzes wurden für die 13 verschiedenen Baumarten und das Splint- und Kernholz signifikante Unterschiede bezüglich III der lignocellulolytischen Enzymaktivitäten und der analysierten Totholzvariablen (z.B. pHWert, Ligningehalt, Pilzbiomasse, wasserlösliche Ligninfragmente, bioverfügbare Elemente) gefunden. Die Enzymaktivitäten und die physikalisch-chemischen Totholzvariablen sowie die Nährstoffe und Metallgehalte waren zumeist im Laubholz höher als im Nadelholz sowie im Splintholz höher als im Kernholz. Die Aktivitäten der Lignin-modifizierenden Enzyme waren sehr variabel in den untersuchten Totholzproben, wobei hohe mittlere Lac-, GenP- und MnP-Aktivitäten nur in einzelnen Baumgattungen (> 50 mU g-1; Carpinus, Fagus, Betula, Acer, Tilia, Populus) ermittelt wurden. Hingegen wurden relevante mittlere cellulolytische und hemicellulolytische Enzymaktivitäten in fast jeder Baumart gefunden. Die ermittelte Pilzbiomasse korrelierte positiv mit dem Stickstoffgehalt und der pilzlichen Gemeinschaft, hingegen negativ mit den Extraktiven und der ermittelten Artenzahl. Weiterhin sollten die Unterschiede der pilzlichen Artengemeinschaft in den verschiedenen Baumarten sowie im Splint- und Kernholz geklärt werden. Generell zeigten sich signifikante Unterschiede in der Zusammensetzung der pilzlichen Gemeinschaft innerhalb der 13 Baumarten, jedoch wurde kein signifikanter Unterschied zwischen den Splint- und Kernholzproben gefunden. Es kann davon ausgegangen werden, dass eine Besiedlung durch Pilze vom Splintholz zum Kernholz hin erfolgt und sich die pilzliche Gemeinschaft zwischen dem Splint- und Kernholz nicht signifikant ändert während der Besiedlung. Neben der Pilzbiomasse korrelierten der pH-Wert, die organischen Extraktive und der Gehalt an Lignin positiv mit der Pilzgemeinschaft. Insgesamt ließen sich 194 Familien nachweisen, wobei die am häufigsten vorkommenden Pilzfamilien die Helotiaceae und Polyporaceae waren. Die Pilzart Ascocoryne sarcoides der Familie Helotiaceae dominierte in Betula und Pinus sowie im Kernholz von Fagus und Fraxinus. Die zweithäufigste Art, Bjerkandera adusta aus der Familie Meruliaceae, dominierte generell die Totholzproben in dieser Arbeit. Auch die Betrachtung der molekularen pilzlichen Gemeinschaftsstruktur in Bezug zu den Enzymaktivitäten ergab für einige Enzyme (z.B. Lac, MnP) positive Korrelationen. Die Sequenzabundanzen der Weißfäulepilze und der Meruliaceae zeigten signifikant positive Korrelationen zur Aktivität der Mangan-Peroxidase. Das häufige Auftreten von Weißfäulepilzen sowie die gleichzeitige Präsenz oxidativer Enzymaktivitäten und charakteristischer Molekularmassenverteilungen der wasserlöslichen Ligninfragmente lassen auf die fundamentale Bedeutung von Peroxidasen für die Zersetzung des Totholzes schließen. Einen direkten Zusammenhang der Metallkonzentrationen mit den oxidativen Enzymaktivitäten wurde nur in Teilen beobachtet, da einzig die Aktivität der Laccase positiv mit dem Gehalt an Kupfer korrelierte.
Abschließend erfolgte die Untersuchung des Genoms des häufig in den Totholzproben präsenten Ascomyceten Coniochaeta (Lecythophora) hoffmannii. Da Pilze aus der Familie Coniochaetaceae ubiquitär im Totholz zu finden sind, aber nur wenig über ihre Biologie bekannt ist, sollte die Sequenzierung des Genoms Auskunft über ihre Gene, die möglicherweise am Abbau beteiligt sind, geben. Die Analyse des Genoms von C. hoffmanii ergab 629 putative Enzyme und assoziierte Protein-Module (CAZymes, carbohydrate-active enzymes), darunter 74 aus der CBM Proteinfamilie (carbohydrate-binding modules). Echte lignolytische Peroxidasen (MnP, LiP oder VP) wurden allerdings nicht gefunden.:Zusammenfassung II
Abstract V
Inhaltsverzeichnis IX
Abkürzungsverzeichnis XII
1 Einleitung 1
1.1 Entstehung und Vorkommen von Totholz 4
1.2 Bedeutung von Totholz 7
1.3 Biodiversität im Totholz 11
1.4 Anatomie und chemischer Aufbau des Holzes 15
1.4.1 Die Holzstruktur 15
1.4.2 Die pflanzlichen Zellwandkomponenten und der Lignocellulose-Komplex 17
1.5 Holzzersetzende Pilze und ihre ökophysiologische Einteilung 23
1.6 Enzymatik des pilzlichen Totholzabbaus 27
1.6.1 Enzymatische Hydrolyse der Polysaccharide im Holz 28
1.6.2 Abbau und Modifizierung des Lignins durch oxidative Enzyme 30
1.7 Stand der Totholz–Forschung in den Deutschen Biodiversitäts-Exploratorien .34
2 Zielstellungen 39
3 Material und Methoden 42
3.1 Materialien 42
3.1.1 Untersuchungen am natürlichen Totholz 42
3.1.1.1 Untersuchungsgebiet Hainich-Dün 42
3.1.1.2 Plot-Design und Beprobung der Stämme auf den VIP-Flächen 44
3.2 Methoden 45
3.2.1 Aufbereitung der Totholzproben 45
3.2.2 Photometrische Bestimmung enzymatischer Aktivitäten 46
3.2.2.1 Oxidative Enzymaktivitäten 46
3.2.2.2 Aktivitäten der Endo-1,4-β-Cellulase und Endo-1,4-β-Xylanase 48
3.2.3 HPLC-basierte Methoden zur Bestimmung enzymatischer Aktivitäten 49
3.2.3.1 Bestimmungen hydrolytischer Aktivitäten mittels HPLC-DAD 49
3.2.3.2 Untersuchung der wasserlöslichen Lignin-Fragmente mittels HPSEC .52
3.2.3.3 Bestimmung der pilzlichen Biomasse 53
3.2.4 Bestimmung der physikalischen und chemischen Holzparameter 54
3.2.4.1 Organische Extraktive 54
3.2.4.2 KLASON-Lignin und säurelösliches Lignin 55
3.2.4.3 Bioverfügbare Metalle 56
3.2.4.4 Ermittlung des Kohlenstoff- und Stickstoffgehalts 56
3.2.5 Bestimmung der molekularen pilzlichen Diversität im Totholz 57
3.2.6 Analyse der Genome ausgewählter holzzersetzender Pilze 59
3.3 Statistiken 60
4 Ergebnisse 62
4.1 Enzymatische Aktivitäten in den 13 Baumarten 62
4.1.1 Oxidative Enzyme 63
4.1.2 Hydrolytische Enzyme 65
4.2 Unterschiede in Totholzvariablen und Elementen in den verschiedenen Baumarten 68
4.2.1 Totholzvariablen 68
4.2.2 Nährstoffgehalte und Elemente 74
4.2.3 Korrelationen zwischen den ligninolytischen Enzymaktivitäten und
verschiedenen Totholzvariablen 79
4.3 Die Struktur der pilzlichen Gemeinschaft und die Artenzahl 80
4.3.1 Die Struktur der pilzlichen Artengemeinschaft 81
4.3.2 Ökologie der gefundenen Pilzarten 88
4.3.3 Pilzliche Artenzahl 89
4.3.4 Korrelationen zwischen Pilzgemeinschaft, Enzymaktivitäten und physikalisch-chemischen Parametern 91
4.3.5 Korrelationen der Pilzfamilien und Ökotypen mit den Enzymaktivitäten 96
4.4 Genomanalyse von Coniochaeta (Lecythophora) hoffmanii 97
5 Diskussion 100
5.1 Allgemeine Unterschiede zwischen den Baumarten 100
5.1.1 Totholzvariablen, Nährstoffe und bioverfügbare Elemente 100
5.1.2 Die lignocellulolytischen Enzymaktivitäten 106
5.1.2.1 Lignin-modifizierende Enzyme (LME) 106
5.1.2.2 Cellulolytische und hemicellulolytische Enzyme 113
5.2 Die pilzliche Artengemeinschaft 119
5.2.1 Dominierende Pilzfamilien, Pilzarten und ökophysiologische Pilzgruppen 122
5.2.2 Zusammenhänge zwischen der pilzlichen Diversität und den abiotischen sowie
biotischen Variablen des Totholzes 127
5.2.2.1 Zusammenspiel der molekularen Pilzgemeinschaft mit Totholzparametern
und Enzymaktivitäten 127
5.2.2.2 Die Variabilität der molekularen Artenzahl und der Totholzparameter 131
5.2.2.3 Unterschiede zwischen den ökophysiologischen Pilzgruppen 132
5.2.2.4 Zusammenhänge zwischen ausgewählten Pilzfamilien und den Enzym-
Aktivitäten 133
6 Ausblick 136
Literaturverzeichnis 138
Anhang 172
Publikationen 178
Danksagung 215
Eidesstattliche Erklärung 217 / Deadwood is an important structural element and particularly relevant in forest ecosystems, as it serves as habitat and substrate for numerous organisms. Furthermore, it contributes to the carbon and nutrient cycle. Saprotrophic fungi from the phyla Basidiomycota and Ascomycota have developed various ecological and physiological strategies to efficiently decompose deadwood. Particularly, white-rot fungi play a crucial role in deadwood decomposition. They are able to oxidatively attack, chemically modify and degrade lignin with their extracellular enzymes such as laccases and various peroxidases. Nevertheless, little is known about the degradation process by lignocellulolytic enzymes in natural deadwood and the responsible fungal communities as well as on abiotic factors influencing decomposition. Therefore, the goal of this thesis within the BELongDead project (part of the German Biodiversity Exploratories) has been to investigate the fungal degradation of deadwood in the advanced initial phase (after about six years) of the decay process. Furthermore, the role of lignocellulolytic enzymes was analyzed and their dependence on various physical and chemical deadwood variables was shown. In addition, the thesis aims at clarifying the influence of the composition of the fungal community on deadwood decomposition and at answering the question which fungal species and ecotypes dominate during that process. For this purpose, natural deadwood logs of 13 tree species (Acer sp., Betula sp., Carpinus betulus, Fagus
sylvatica, Fraxinus excelsior, Larix decidua, Picea abies, Pinus sylvestris, Populus sp., Prunus avium, Pseudotsuga menziesii, Quercus sp sp.) were analyzed in the Hainich-Dün National Park in Thuringia (Germany). Moreover, the fungal decomposition process was separately considered with regard to sapwood and heartwood. A total of 82 deadwood samples were taken to analyze the activities of the lignin-modifying enzymes (laccase/Lac, General peroxidase/GenP, manganese peroxidases/MnP) and various (hemi)cellulolytic enzymes (Polysaccharide hydrolases); enzymes that play a role in the nitrogen, phosphorus and sulfur cycles were considered as well. Moreover, deadwood variables such as fungal biomass, pH, water content, water-soluble lignin fragments, lignin and extractive content as well as nutrients (C, N, C: N) and metals (Ca, Cu, K, Mg, Mn and Zn) were also determined. The fungal community structure and species richness were analyzed by using a Next Generation Sequencing method (Illumina MiSeq).
Because of the varying physical and chemical characteristics, significant differences were ascertained for lignocellulolytic enzyme activities and analyzed deadwood variables (e.g. pH, lignin content, fungal biomass, water soluble lignin fragments, bioavailable elements) between the 13 different tree species and between sapwood and heartwood. Generally speaking, the enzyme activities and the physico-chemical deadwood variables as well as the nutrients and metal contents were higher in deciduous than in coniferous trees and higher in sapwood than in heartwood. The activities of lignin-modifying enzymes were highly variable in the deadwood samples and relative high mean values of Lac, GenP and MnP were determined only in few tree species (> 50 mU g-1; Carpinus, Fagus, Betula, Acer, Tilia, Populus). By contrast, relevant mean activities of cellulolytic and hemicellulolytic Enzymes were found to be present in almost any tree species. The measured fungal biomass correlated positively with the content of nitrogen and the fungal community structure, but was negatively correlated with the organic extractives and the determined fungal species richness. Furthermore, the differences in the fungal species community structure of different tree species as well as in sapwood and heartwood were clarified. In general, there were significant differences in the composition of the fungal communities among the 13 tree species, but no significant difference was observed between sapwood and heartwood. Thus, it can be assumed that fungal colonization by fungi appears to proceed from sapwood towards heartwood and as the result, significant differences regarding the communities were not detected. In addition to fungal biomass, the pH, organic extractives and the content of lignin positively correlated with the fungal community structure. Altogether, 194 fungal families were found, with Helotiaceae and Polyporaceae being the most common ones. The fungus Ascocoryne sarcoides of the ascomycetous family Helotiaceae dominated in Betula and Pinus as well as in the heartwood of Fagus and Fraxinus. The second most common species, Bjerkandera adusta of the basidiomycetous family Meruliaceae, generally dominated the deadwood samples in this work. Furthermore, in some cases, positive correlations were found between the molecular fungal community structure and some enzyme activities (e.g. Lac, MnP). The sequence abundances of white-rot fungi and the Meruliaceae showed significant positive correlations with the activity of MnP. The frequent occurrence of white-rot fungi as well as the simultaneous presence of oxidative enzyme activities and characteristic molecular mass distributions of the water-soluble lignin fragments proved the fundamental importance of peroxidases for the decomposition of deadwood, particularly with respect to lignin degradation. A direct dependency of oxidative enzyme activities from metals was only discontinuously ascertained, since just the activity of Lac correlated positively with the content of copper.
Finally, the genome of the abundant (in the Hainich samples) ascomycetous species Coniochaeta (Lecythophora) hoffmannii was sequenced and analyzed. Since fungi of the family Coniochaetaceae are ubiquitously found in deadwood and on the other hand, merely little is known on their biology, sequencing of the genome should provide information about the putative enzymes/genes involved in wood degradation. The analysis of the genome of C. hoffmannii identified 629 potential enzymes and associated proteins/ modules (CAZymes, carbohydrate-active enzymes), including 74 from the CBM protein family (carbohydratebinding modules). However, true ligninolytic peroxidases (MnP, LiP or VP) were not found.:Zusammenfassung II
Abstract V
Inhaltsverzeichnis IX
Abkürzungsverzeichnis XII
1 Einleitung 1
1.1 Entstehung und Vorkommen von Totholz 4
1.2 Bedeutung von Totholz 7
1.3 Biodiversität im Totholz 11
1.4 Anatomie und chemischer Aufbau des Holzes 15
1.4.1 Die Holzstruktur 15
1.4.2 Die pflanzlichen Zellwandkomponenten und der Lignocellulose-Komplex 17
1.5 Holzzersetzende Pilze und ihre ökophysiologische Einteilung 23
1.6 Enzymatik des pilzlichen Totholzabbaus 27
1.6.1 Enzymatische Hydrolyse der Polysaccharide im Holz 28
1.6.2 Abbau und Modifizierung des Lignins durch oxidative Enzyme 30
1.7 Stand der Totholz–Forschung in den Deutschen Biodiversitäts-Exploratorien .34
2 Zielstellungen 39
3 Material und Methoden 42
3.1 Materialien 42
3.1.1 Untersuchungen am natürlichen Totholz 42
3.1.1.1 Untersuchungsgebiet Hainich-Dün 42
3.1.1.2 Plot-Design und Beprobung der Stämme auf den VIP-Flächen 44
3.2 Methoden 45
3.2.1 Aufbereitung der Totholzproben 45
3.2.2 Photometrische Bestimmung enzymatischer Aktivitäten 46
3.2.2.1 Oxidative Enzymaktivitäten 46
3.2.2.2 Aktivitäten der Endo-1,4-β-Cellulase und Endo-1,4-β-Xylanase 48
3.2.3 HPLC-basierte Methoden zur Bestimmung enzymatischer Aktivitäten 49
3.2.3.1 Bestimmungen hydrolytischer Aktivitäten mittels HPLC-DAD 49
3.2.3.2 Untersuchung der wasserlöslichen Lignin-Fragmente mittels HPSEC .52
3.2.3.3 Bestimmung der pilzlichen Biomasse 53
3.2.4 Bestimmung der physikalischen und chemischen Holzparameter 54
3.2.4.1 Organische Extraktive 54
3.2.4.2 KLASON-Lignin und säurelösliches Lignin 55
3.2.4.3 Bioverfügbare Metalle 56
3.2.4.4 Ermittlung des Kohlenstoff- und Stickstoffgehalts 56
3.2.5 Bestimmung der molekularen pilzlichen Diversität im Totholz 57
3.2.6 Analyse der Genome ausgewählter holzzersetzender Pilze 59
3.3 Statistiken 60
4 Ergebnisse 62
4.1 Enzymatische Aktivitäten in den 13 Baumarten 62
4.1.1 Oxidative Enzyme 63
4.1.2 Hydrolytische Enzyme 65
4.2 Unterschiede in Totholzvariablen und Elementen in den verschiedenen Baumarten 68
4.2.1 Totholzvariablen 68
4.2.2 Nährstoffgehalte und Elemente 74
4.2.3 Korrelationen zwischen den ligninolytischen Enzymaktivitäten und
verschiedenen Totholzvariablen 79
4.3 Die Struktur der pilzlichen Gemeinschaft und die Artenzahl 80
4.3.1 Die Struktur der pilzlichen Artengemeinschaft 81
4.3.2 Ökologie der gefundenen Pilzarten 88
4.3.3 Pilzliche Artenzahl 89
4.3.4 Korrelationen zwischen Pilzgemeinschaft, Enzymaktivitäten und physikalisch-chemischen Parametern 91
4.3.5 Korrelationen der Pilzfamilien und Ökotypen mit den Enzymaktivitäten 96
4.4 Genomanalyse von Coniochaeta (Lecythophora) hoffmanii 97
5 Diskussion 100
5.1 Allgemeine Unterschiede zwischen den Baumarten 100
5.1.1 Totholzvariablen, Nährstoffe und bioverfügbare Elemente 100
5.1.2 Die lignocellulolytischen Enzymaktivitäten 106
5.1.2.1 Lignin-modifizierende Enzyme (LME) 106
5.1.2.2 Cellulolytische und hemicellulolytische Enzyme 113
5.2 Die pilzliche Artengemeinschaft 119
5.2.1 Dominierende Pilzfamilien, Pilzarten und ökophysiologische Pilzgruppen 122
5.2.2 Zusammenhänge zwischen der pilzlichen Diversität und den abiotischen sowie
biotischen Variablen des Totholzes 127
5.2.2.1 Zusammenspiel der molekularen Pilzgemeinschaft mit Totholzparametern
und Enzymaktivitäten 127
5.2.2.2 Die Variabilität der molekularen Artenzahl und der Totholzparameter 131
5.2.2.3 Unterschiede zwischen den ökophysiologischen Pilzgruppen 132
5.2.2.4 Zusammenhänge zwischen ausgewählten Pilzfamilien und den Enzym-
Aktivitäten 133
6 Ausblick 136
Literaturverzeichnis 138
Anhang 172
Publikationen 178
Danksagung 215
Eidesstattliche Erklärung 217
|
137 |
Suivi simultané de la consommation d'oxygène et de la consistance des pâtes de farine de blé à l'aide d'un pétrin instrumenté (le sitoxygraphe) : tentative d'explication biochimique et rhéologique. Application à l'ajout de laccasesLevavasseur, Loïc 03 April 2007 (has links) (PDF)
Le pétrissage des pâtes constitue une étape clé en panification qui conduit au développement des réseaux de gluten et d'arabinoxylanes. Lors du pétrissage, les réactions d'oxydation, pour la plupart enzymatiques, participent à l'acquisition des propriétés viscoélastiques de la pâte et contribuent à la qualité du produit final. Afin de mesurer et caractériser les réactions d'oxydations au seins de la pâte, l'objectif de ce travail de thèse est la mise au point d'un pétrin pilote, le sitoxygraphe, instrumenté pour la mesure directe de la consommation et des vitesse de consommation d'oxygène et de l'évolution du couple s'exerçant sur le bras mobile du pétrin. Ces mesures ont permis d'étudier l'influence de la composition biochimique des farines sur les consommations d'oxygène et sur les paramètres de couple, confirmant l'importance du système lipoxygénasique dans les premiers instants de pétrissage ainsi que la probable participation de réactions secondaires. Les corrélations entre les données oxygène et les paramètres de couple ainsi qu'entre les paramètres de couple du sitoxygraphe et des données rhéologiques ont mis en évidence la contribution des réactions d'oxydation dans l'acquisition des propriétés rhéologiques de la pâte. Quelques effets d'améliorants connus ont également été mesurés. Enfin, après avoir sélectionné deux laccases (polyphénoloxydases) potentiellement intéressantes en panification, leurs effets au cours du pétrissage ont été étudiés mettant en évidence un effet positif sur la consommation d'oxygène et négatif sur les paramètres de couple (probable suroxydation). L'oxydation de composés endogènes par ces enzymes via un médiateur d'oxydation constitue une voie intéressante.
|
138 |
The Use of Lignin Derivatives to Improve Selected Paper PropertiesAntonsson, Stefan January 2007 (has links)
<p>Ved består huvudsakligen av tre typer av polymerer, cellulosa, hemicellulosa och lignin. Lignin bildas i naturen genom enzymatiskt initierad oxidativ koppling av tre olika typer av fenylpropan-enheter. Dessa bygger genom olika kol-kol- och kol-syre-bindningar upp en amorf tredimensionell polymer. När kemisk massa tillverkas bryts lignin ner och löses ut i kokluten. Luten innehåller de förbrukade kokkemikalierna och bränns generellt i en sodapanna för att regenerera kemikalierna och producera ånga. Sodapannan är emellertid dyr. Därför har den blivit produktionsbegränsande på många massabruk. Att avlägsna en del av ligninet från avluten vore därför önskvärt och att finna ekonomiskt intressanta produkter baserade på lignin från svartlut är därför ett viktigt forskningsområde .</p><p>Ett lämpligt område för ligninprodukter vore som tillsatts i oblekt massa. Oblekt massa används till stor del för tillverkning av kraftliner, topp- och bottenskikten på wellpapp. När lådor av wellpapp lagras i containrar som färdas över haven, förändras den relativa luftfuktigheten. Detta gör att lådorna kollapsar lättare än om de skulle ha lagrats vid konstant luftfuktighet, även en hög sådan. Detta är på grund av det så kallade mekanosorptiva- eller accelererade krypfenomenet. Genom tillsatts av våtstyrkemedel till kraftliner eller behandla den med hydrofoba ämnen, finns indikatoner på att mekanosorptiva effekten skulle kunna minska.</p><p>För att försöka minska den effekten har ett lågmolekylärt kraftlignin, som utvunnits med hjälp av tvärsflödesfiltrering av svartlut och svavelsyrafällning, använts. Genom derivatisering av detta lignin med linolja erhölls ett hydrofobt ligninderivat som uppvisar strukturella likheter med biopolymeren suberin. När detta suberinlika ligninderivat tillsätts till massa verkar det mekanosorptiva krypet minska. När lågmolekylärt lignin används tillsammans med ligninradikalinitiatorerna lackas eller mangan(III) i kraftlinermassa erhålls dessutom en våtstyrka på ca 5% av torrstyrkan. Efter aminering av detta lignin gav en tillsatts till kraftlinermassan en våtstyrka på upp till 10% av torrstyrkan. Det finns indikationer på att det mekanosorptiva krypet samtidigt minskar när dessa behandlingar görs som ger upphov till ökad våtstyrka.</p> / <p>Wood consists mainly of three types of polymers; cellulose, hemi cellulose and lignin. Lignin is formed in nature through enzymatic initiated oxidative coupling of three different kinds of phenyl propane units. These form by various carbon-carbon and carbon-oxygen bonds, an amorphous three-dimensional polymer. As chemical pulp is produced, lignin is degraded and dissolved into pulping liquors. These liquors contain the spent cooking chemicals and are generally burnt in a recovery boiler to regenerate cooking chemicals and produce steam. However, the recovery boiler is expensive. Hence, it has become the bottleneck for production in many pulp mills. Removal of some lignin from the spent cooking liquor would, for that reason, be desired and valuable products based on lignin from cooking liquors are searched for.</p><p>One suitable area for lignin products would be as additive in unbleached pulp. A major product from unbleached pulp is kraftliner, the top and bottom layers of corrugated board. When boxes of corrugated board are stored in containers travelling overseas the relative humidity is varying. This makes the boxes collapse more easily than if they were stored at constant humidity, even a high one. This is due to the so called mechano-sorptive or accelerated creep phenomenon. By addition of wet strength additive to kraftliner or treating it with hydrophobic compounds there are indications on that the mechano-sorptive effect would decrease.</p><p>Trying to decrease this effect, low molecular weight kraft lignin has been used. It was obtained by cross-flow filtration of black liquor and precipitation by sulphuric acid. By derivatisation of this lignin by linseed oil, a hydrophobic lignin derivative was obtained, similar in structure to units in the biopolymer suberin. As this suberin-like lignin-derivative was added to pulp the mechano-sorptive creep seemed to be lowered. Furthermore, when the low molecular weight lignin was used together with the lignin radical initiators laccase or manganese(III) in kraftliner pulp, a wet strength of about 5% of dry strength was obtained. An amination treatment of this lignin and addition to kraftliner pulp resulted in a wet strength of up to 10% of dry strength. There are indications of that the mechano-sorptive creep also decreases as these treatments, resulting in increased wet strength, are made.</p>
|
139 |
Redução do Acefato utilizando lacases produzidas por Trametes villosa e Pycnoporus sanguineus com Trichodermas isolados do Cerrado / Reduction of the laccases produced by using acephate Trametes villosa and Pycnoporus sanguineus Trichoderma with isolated from SavannaSILVA, Carolina Braz 23 August 2011 (has links)
Made available in DSpace on 2014-07-29T15:01:45Z (GMT). No. of bitstreams: 1
Carolina Braz Silva.pdf: 810800 bytes, checksum: 70f05bacdef63b8aef2325761ace6cca (MD5)
Previous issue date: 2011-08-23 / The organophosphate insecticides have been widely used for agricultural purposes. In the environment, organophosphates have been found in various environmental matrices, resulting in a growing environmental concern, among these compounds
stands out Acephate, organophosphate and was registered by ANVISA reassessed in 2009, due to their toxicological and carcinogenic potential. The development of this work sought to select strains of Trichoderma harzianum capable of stimulating enzyme production by Trametes villosa and Pycnoporus sanguineus to promote the reduction of toxicity of Acephate. First there was the selection of strains of T.
harzianum then became mixed cropping of selected strains of T. harzianum with Trametes villosa and T. harzianum with Pycnoporus sanguineus to determine the potential production of enzymes, and further tests were carried out with
concentrations of 10% and 50% Acephate then held the toxicity test to assess the reduction of toxicity of Acephate. The results obtained in the experiments show that linhanges T. harzianum are good producers of lignin peroxidase (45 U.mL-1) and manganese peroxidase (23 Uml-1), the strains of T. harzianum were able to increase the production of Laccase in culture with T. villosa (20.57 Uml-1) and assessed that the fungi produced more enzymes in the presence of 50% Acephate. In toxicity tests, the samples with 10% Acephate addressed by the fungi indicated that compared to control, the association of P. sanguineus and Trichoderma T47
increased by 94% of cholinesterase, indicating a decrease in its toxicity, the association of P. sanguineus and Trichoderma harzianum ALL42 increase of 93% and the association between T. villosa and T. harzianum T39, an increase of 100%
of cholinesterase, indicating that fungi were able to reduce the toxicity of Acephate. / Os inseticidas organofosforados têm sido amplamente utilizados para fins agrícolas. No ambiente, os
organofosforados têm sido encontrados em diversas matrizes ambientais, resultando em uma crescente preocupação ambiental, dentre estes compostos destaca-se o Acefato, organofosforado que teve seu registro reavaliado pela ANVISA em 2009, devido ao seu potencial toxicológico e carcinogênico. O desenvolvimento deste trabalho buscou
selecionar linhagens de Trichoderma harzianum capazes de estimular a produção enzimática por Trametes villosa e Pycnoporus sanguineus a fim de promover a diminuição da toxicidade do Acefato. Primeiramente realizou-se a seleção das linhagens de T. harzianum, em seguida fez-se o cultivo misto das linhagens selecionadas de T. harzianum com
Trametes villosa e T. harzianum com Pycnoporus sanguineus para verificar o potencial de produção das enzimas, e posteriormente foram realizados os ensaios com concentrações de 10% e 50% de Acefato, em seguida realizou-se os teste de toxicidade para avaliar a redução da toxicidade do Acefato. Os resultados obtidos nos experimentos
demonstram que as linhanges de T. harzianum são bons produtores de Lignina peroxidase (45 U.mL-1) e Manganês peroxidase (23 UmL-1), as linhagens de T. harzianum foram
capazes de aumentar a produção de Lacase no cultivo com T. villosa (20,57 UmL-1) e que os fungos avaliados produziram mais enzimas na presença de 50% de Acefato. Nos testes
de toxicidade, as amostras com 10% de Acefato tratadas pelos fungos indicaram que em relação ao controle, a associação de P. sanguineus e o Trichoderma T47 teve aumento de 94% de Colinesterase, indicando diminuição de sua toxicidade, na associação de P. sanguineus e Trichoderma harzianum ALL42 aumento de 93% e na associação entre T.
villosa e o T. harzianum T39, aumento de 100% de Colinesterase, indicando que os fungos foram capazes de reduzir a toxicidade do Acefato.
|
140 |
The Use of Lignin Derivatives to Improve Selected Paper PropertiesAntonsson, Stefan January 2007 (has links)
Ved består huvudsakligen av tre typer av polymerer, cellulosa, hemicellulosa och lignin. Lignin bildas i naturen genom enzymatiskt initierad oxidativ koppling av tre olika typer av fenylpropan-enheter. Dessa bygger genom olika kol-kol- och kol-syre-bindningar upp en amorf tredimensionell polymer. När kemisk massa tillverkas bryts lignin ner och löses ut i kokluten. Luten innehåller de förbrukade kokkemikalierna och bränns generellt i en sodapanna för att regenerera kemikalierna och producera ånga. Sodapannan är emellertid dyr. Därför har den blivit produktionsbegränsande på många massabruk. Att avlägsna en del av ligninet från avluten vore därför önskvärt och att finna ekonomiskt intressanta produkter baserade på lignin från svartlut är därför ett viktigt forskningsområde . Ett lämpligt område för ligninprodukter vore som tillsatts i oblekt massa. Oblekt massa används till stor del för tillverkning av kraftliner, topp- och bottenskikten på wellpapp. När lådor av wellpapp lagras i containrar som färdas över haven, förändras den relativa luftfuktigheten. Detta gör att lådorna kollapsar lättare än om de skulle ha lagrats vid konstant luftfuktighet, även en hög sådan. Detta är på grund av det så kallade mekanosorptiva- eller accelererade krypfenomenet. Genom tillsatts av våtstyrkemedel till kraftliner eller behandla den med hydrofoba ämnen, finns indikatoner på att mekanosorptiva effekten skulle kunna minska. För att försöka minska den effekten har ett lågmolekylärt kraftlignin, som utvunnits med hjälp av tvärsflödesfiltrering av svartlut och svavelsyrafällning, använts. Genom derivatisering av detta lignin med linolja erhölls ett hydrofobt ligninderivat som uppvisar strukturella likheter med biopolymeren suberin. När detta suberinlika ligninderivat tillsätts till massa verkar det mekanosorptiva krypet minska. När lågmolekylärt lignin används tillsammans med ligninradikalinitiatorerna lackas eller mangan(III) i kraftlinermassa erhålls dessutom en våtstyrka på ca 5% av torrstyrkan. Efter aminering av detta lignin gav en tillsatts till kraftlinermassan en våtstyrka på upp till 10% av torrstyrkan. Det finns indikationer på att det mekanosorptiva krypet samtidigt minskar när dessa behandlingar görs som ger upphov till ökad våtstyrka. / Wood consists mainly of three types of polymers; cellulose, hemi cellulose and lignin. Lignin is formed in nature through enzymatic initiated oxidative coupling of three different kinds of phenyl propane units. These form by various carbon-carbon and carbon-oxygen bonds, an amorphous three-dimensional polymer. As chemical pulp is produced, lignin is degraded and dissolved into pulping liquors. These liquors contain the spent cooking chemicals and are generally burnt in a recovery boiler to regenerate cooking chemicals and produce steam. However, the recovery boiler is expensive. Hence, it has become the bottleneck for production in many pulp mills. Removal of some lignin from the spent cooking liquor would, for that reason, be desired and valuable products based on lignin from cooking liquors are searched for. One suitable area for lignin products would be as additive in unbleached pulp. A major product from unbleached pulp is kraftliner, the top and bottom layers of corrugated board. When boxes of corrugated board are stored in containers travelling overseas the relative humidity is varying. This makes the boxes collapse more easily than if they were stored at constant humidity, even a high one. This is due to the so called mechano-sorptive or accelerated creep phenomenon. By addition of wet strength additive to kraftliner or treating it with hydrophobic compounds there are indications on that the mechano-sorptive effect would decrease. Trying to decrease this effect, low molecular weight kraft lignin has been used. It was obtained by cross-flow filtration of black liquor and precipitation by sulphuric acid. By derivatisation of this lignin by linseed oil, a hydrophobic lignin derivative was obtained, similar in structure to units in the biopolymer suberin. As this suberin-like lignin-derivative was added to pulp the mechano-sorptive creep seemed to be lowered. Furthermore, when the low molecular weight lignin was used together with the lignin radical initiators laccase or manganese(III) in kraftliner pulp, a wet strength of about 5% of dry strength was obtained. An amination treatment of this lignin and addition to kraftliner pulp resulted in a wet strength of up to 10% of dry strength. There are indications of that the mechano-sorptive creep also decreases as these treatments, resulting in increased wet strength, are made. / QC 20101103
|
Page generated in 0.0513 seconds