scholarly journals Effects of Nitrogen Supplements on Degradation of Aspen Wood Lignin and Carbohydrate Components by Phanerochaete chrysosporium†

1983 ◽  
Vol 45 (3) ◽  
pp. 830-837 ◽  
Author(s):  
Ian D. Reid
1980 ◽  
Vol 26 (9) ◽  
pp. 1168-1171 ◽  
Author(s):  
Ian D. Reid ◽  
Keith A. Seifert

Phanerochaete chrysosporium degraded aspen wood lignin as well in 2 atm O2 (1 atm = 101.325 kPa) as in 1 atm O2, but 3 atm O2 inhibited the fungus, and O2 pressures above 4 atm killed it. Lignin degradation in 5 atm of air was similar to that in 1 atm of O2, indicating that O2 concentration, not pressure, was the inhibitory factor. The selectivity with which P. chrysosporium metabolised lignin in preference to other wood components did not increase at O2 pressures above 1 atm.


1982 ◽  
Vol 60 (11) ◽  
pp. 2357-2364 ◽  
Author(s):  
Ian D. Reid ◽  
Garth D. Abrams ◽  
James M. Pepper

When Phanerochaete chrysosporium degrades [14C] lignin-labelled aspen wood in static liquid culture, it releases almost as much 14C in water-soluble form as in 14CO2. Water-soluble ultraviolet-absorbing materials also accumulate in cultures that are degrading lignin. The water-soluble radioactive materials appear to be intermediates in lignin degradation, because they can be further metabolized to CO2 and because the soluble materials labelled during [14C] lignin degradation are distinct from the materials labelled during [14C] glucose metabolism. These lignin degradation products can be fractionated by gel chromatography and are mostly acidic.


1985 ◽  
Vol 31 (1) ◽  
pp. 88-90 ◽  
Author(s):  
Ian D. Reid ◽  
Ema E. Chao ◽  
Peter S. S. Dawson

Contrary to previous reports, cultures of Phanerochaete chrysosporium agitated on a gyrotory shaker degraded synthetic lignin to CO2 approximately as rapidly and extensively as static cultures. Agitated cultures also degraded the lignin in aspen wood to CO2 and water-soluble products as well as static cultures, if the wood particles became enmeshed in the mycelium. An atmosphere of oxygen stimulated lignin degradation, compared with air, in both agitated and static cultures. The mycelia in agitated cultures with ligninolytic activity formed single, large pellets.


1979 ◽  
Vol 57 (19) ◽  
pp. 2050-2058 ◽  
Author(s):  
Ian D. Reid

The degradation by Phanerochaete chrysosporium of "natural" lignin in aspen wood, like synthetic lignin, was inhibited by nitrogen and stimulated by carbohydrate. Nitrogen delayed the appearance and reduced the level of ligninolytic activity and indirectly hastened its decline by accelerating depletion of the carbohydrate supply. The carbon:nitrogen ratio of the medium was a better predictor of lignin degradation than the absolute carbohydrate and nitrogen levels. Unlike nitrogen limitation, sulphate and phosphate limitation of growth did not stimulate lignin metabolism.


1992 ◽  
Vol 7 (1) ◽  
pp. 17-21a ◽  
Author(s):  
Félix Carrasco ◽  
Jacques J. Garceau ◽  
Aziz Ahmed ◽  
Bohuslav V. Kokta
Keyword(s):  

Author(s):  
И.В. Коваленко ◽  
М.А. Чубинский ◽  
Д.С. Русаков ◽  
Г.С. Варанкина

Применение древесины осины в промышленном производстве материалов и изделий ограничено из-за ее низких механических свойств, подверженности поражению коррозионно-деструктивной гнили, отсутствием должного обоснования технологии ее переработки. Невостребованная осина осложняет условия хозяйствования в лесу, ухудшает породный состав древостоев, препятствует восстановлению хвойных пород древесины. Древесина осины хуже смачивается водой по сравнению с другими породами. Изучение ее поверхностных свойств и строения на микроуровне представляет безусловный интерес для изучения взаимодействия древесины с водой, жидкими клеящими и защитно-декоративными веществами. Это сложная многопараметрическая задача, решение которой может явиться новым инструментом для обоснования наукоемких технологических процессов сушки, пропитки, склеивания и облагораживания древесины. Истинная поверхность древесины, образованная в результате обработки резанием (лущением, пилением, фрезерованием) значительно больше ее проекции на плоскости в результате разрезания микроструктурных элементов. Неровности на поверхности искажают результаты измерения поверхностных свойств, определяемых на основе угла смачивания. Учитывая то, что размеры стенок клеток меньше размеров полостей, истинная площадь поверхности древесины, в зависимости от вида разреза, может в десятки раз превышать кажущуюся. Ухудшение способности смачиваться объясняет образование на поверхности капель клея, нанесенного на шпон методом вальцевания. При горячем прессовании фанеры в первый момент времени повышается подвижность молекул клея, снижается упругость древесины, поверхность выравнивается, улучшая условия адгезионного взаимодействия связующего и древесины. Для определения истинных характеристик древесины, обоснования расхода клея, способности древесины поглощать жидкость необходимо знать размеры ее микроструктурных элементов и характер их распределения, объем поверхностных полостей. Эффективный радиус полостей древесины осины может быть описан с использованием теории фракталов. The use of aspen wood in manufacturing of materials and products is limited due to its low mechanical properties, corrosion susceptibility destructive lesion decay, its lack of proper justification processing technology. Unclaimed aspen difficult economic conditions in the forest, degrades the species composition of forest stands and prevents restoration of softwood. Wood aspen worse moistened with water compared to other breeds. The study of its structure and surface properties at the micro level is of great interest to study the interaction of wood with water, liquid adhesives and protective-decorative materials. This is the problem whose solution can be a new tool for the study of science-intensive technological processes of drying, impregnation, gluing and surface finishes. Real wood surface, formed by the machining (peeling, sawing, milling) significantly greater its projection on the plane as a result of cutting the microstructural elements. Surface irregularities distort the results of measurement of surface properties which are determined based on the contact angle. Given that the size of the cell walls is less than the size of the cavities, the true surface area of the veneer, depending on the type of incision, may be ten times the apparent. The deterioration of the ability of wetted explains the formation of droplets on the surface of adhesive deposited on the veneer by rolling. When plywood hot pressing at a first time increases mobility of adhesive molecules, decreases the modulus of elasticity of wood, surface is aligned, improving the conditions of interaction of the glue and the wood. To determine the true characteristics of the wood, glue flow study, the ability of wood to absorb liquid it is necessary to know the size of microstructural elements and their distribution, the amount of surface cavities. The effective radius of aspen wood cavities can be described using fractal theory.


2004 ◽  
Vol 4 (4) ◽  
pp. 175-182 ◽  
Author(s):  
K. Rojek ◽  
F.A. Roddick ◽  
A. Parkinson

Phanerochaete chrysosporium was shown to rapidly decolorise a solution of natural organic matter (NOM). The effect of various parameters such as carbon and nitrogen content, pH, ionic strength, NOM concentration and addition of Mn2+ on the colour removal process was investigated. The rapid decolorisation was related to fungal growth and biosorption rather than biodegradation as neither carbon nor nitrogen limitation, nor Mn2+ addition, triggered the decolorisation process. Low pH (pH 3) and increased ionic strength (up to 50 g L‒1 added NaCl) led to greater specific removal (NOM/unit biomass), probably due to increased electrostatic bonding between the humic material and the biomass. Adsorption of NOM with viable and inactivated (autoclaved or by sodium azide) fungal pellets occurred within 24 hours and the colour removal depended on the viability, method of inactivation and pH. Colour removal by viable pellets was higher under the same conditions, and this, combined with desorption data, confirmed that fungal metabolic activity was important in the decolorisation process. Overall, removals of up to 40–50% NOM from solution were obtained. Of this, removal by adsorption was estimated as 60–70%, half of which was physicochemical, the other half metabolically-dependent biosorption and bioaccumulation. The remainder was considered to be removed by biodegradation, although some of this may be ascribed to bioaccumulation and metabolically-dependent biosorption.


Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Hüseyin Pelit ◽  
Fatih Emiroglu

AbstractIn this study, the effect of thermo-mechanical densification on the density, hardness, compression strength, bending strength (MOR), and modulus of elasticity (MOE) of fir and aspen wood pretreated with water repellents was analyzed. Wood specimens were impregnated with paraffin, linseed oil and styrene after pre-vacuum treatment. Then, the impregnated wood specimens were densified with compression ratios of 20 and 40%, and at 120, 150 and 180 °C. The results indicated that the density, hardness and strength properties of the all densified specimens (untreated and impregnated) increased depending on the compression ratio and temperature. For all tested properties, higher increases were obtained in the paraffin and styrene pretreated specimens compared to untreated samples. However, the increase rates in linseed oil pretreated specimens were generally lower than untreated specimens. Regarding water repellents the most successful results in all tested properties were determined in styrene pretreated specimens. The density, hardness and strength properties of all specimens increased with the increase in compression ratio. On the other hand, the increase in the compression temperature negatively affects the properties of untreated and linseed oil pretreated specimens, while having a generally positive effect on the properties of paraffin pretreated specimens. However, all tested properties of styrene pretreated specimens have increased significantly due to the increase in compression temperature. The increasing strength properties of wood as a result of densification have increased much more with paraffin and especially styrene pretreatment. These combinations can be considered as an important potential for applications that require more hardness and strength.


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