Single stage and two-stage sodium sulfite cooking were carried out on either spruce, pine or pure pine heartwood chips to investigate the influence of several process parameters on the initial phase of such a cook down to about 60 % pulp yield. The cooking experiments were carried out in the laboratory with either a lab-prepared or a mill-prepared cooking acid and the temperature and time were varied. The influences of dissolved organic and inorganic components in the cooking liquor on the final pulp composition and on the extent of side reactions were investigated. Kinetic equations were developed and the activation energies for delignification and carbohydrate dissolution were calculated using the Arrhenius equation. A better understanding of the delignification mechanisms during bisulfite and acid sulfite cooking was obtained by analyzing the lignin carbohydrate complexes (LCC) present in the pulp when different cooking conditions were used. It was found that using a mill-prepared cooking acid beneficial effect with respect to side reactions, extractives removal and higher stability in pH during the cook were observed compared to a lab-prepared cooking acid. However, no significant difference in degrees of delignification or carbohydrate degradation was seen.  The cellulose yield was not affected in the initial phase of the cook however; temperature had an influence on the rates of both delignification and hemicellulose removal. It was also found that the  corresponding activation energies increased in the order:  xylan, glucomannan, lignin and cellulose. The cooking temperature could thus be used to control the cook to a given carbohydrate composition in the final pulp. Lignin condensation reactions were observed during acid sulfite cooking, especially at higher temperatures. The LCC studies indicated the existence of covalent bonds between lignin and hemicellulose components with respect to xylan and glucomannan. LCC in native wood showed the presence of phenyl glycosides, ϒ-esters and α-ethers; whereas the α-ethers  were affected during sulfite pulping. The existence of covalent bonds between lignin and wood polysaccharides might be the rate-limiting factor in sulfite pulping. / The sulfite pulping process is today practised in only a small number of pulp mills around the globe and the number of sulfite mills that use sodium as the base (cation) is less than five. However, due to the increasing interest in the wood based biorefinery concept, the benefits of sulfite pulping and especially the sodium based variety, has recently gained a lot of interest. It was therefore considered to be of high importance to further study the sodium based sulfite process to investigate if its benefits could be better utilized in the future in the production of dissolving pulps. Of specific interest was to investigate how the pulping conditions in the initial part of the cook (≥ 60 % pulp yield) should be performed in the best way. Thus, this thesis is focused on the initial phase of sodium based single stage bisulfite, acid sulfite and two-stage sulfite cooking of either 100 % spruce, 100 % pine or 100 % pine heartwood chips. The cooking experiments were carried out with either a lab prepared or a mill prepared cooking acid and the temperature and cooking time were varied. Activation energies for different wood components were investigated as well as side reactions concerning the formation of thiosulfate. LCC (Lignin carbohydrates complexes) studies were carried out to investigate the influence of different cooking conditions on lignin carbohydrate linkages.

A digestibilidade in vitro da matéria seca e da parede celular, de diferentes amostras vegetais arranjadas em três grupos: forragens, madeiras ou bambus, foi correlacionada com os teores de lignia estimados por três métodos analíticos. Os métodos empregados foram: lígnina em detergente ácido (LDA). lignina Klason (LK) e lignina permanganato de potássio (LPer). Os teores de lignina foram diferentes entre os métodos, para as mesmas amostras analisadas, sendo no geral maiores para LK e LPer. Para quase todas as amostras, os teores de lignina foram negativamente correlacionadas com a digestibilidade in vitro da matéria seca e da parede celular. O método LDA estimou razoavelmente bem a digestibilidade de forrageiras e bambus, seguindo-se a LPer. A LK não estimou bem a digestibilidade de gramíneas. Quanto às madeiras, nenhum dos três métodos foi um bom indicador da digestibilidade, mesmo o método LK, tradicionalmente usado para madeiras. Conclui-se que, nenhum dos três métodos foi totalmente satisfatório, sugerindo que a determinação analítica da lignina seja mais profundamente estudada. / The in vitro digestibility either dry matter or cell wall of different vegetable samples arranged in three groups: forages, wood or bamboos was correlated with lignin concentration determined through three analytical methods. The employed methods were: acid detergent lignin (ADL), Klason lignin (KL) and potassium permanganate lignin (PerL). Lignin concentrations were different among the methods for the same samples, generally larger for KL and PerL. For almost all samples, lignin concentration was negatively correlated with in vitro digestibility of dry matter and cell wall. ADL method predicted digestibility of grasses and bamboos reasonably well, followed by PerL. KL content was not a good predictor of grass digestibility. Concerning woods, none of the three methods was a good predictor of digestibilty, even the KL method, traditionally used for wood. It is concluded that none of the three methods was totally satisfactory, suggesting that analytical determination of lignin needs more research effort.

Quantificou-se o teor de lignina em cinco amostras de plantas forrageiras, nas frações caule e folha, em quatro estádios de maturidade, através de três métodos analíticos: lignina detergente ácido (LDA), lignina permanganato de potássio (LPer) e lignina Klason (LK), todos de natureza gravimétrica. Os três métodos não foram concordantes entre si, sendo que para a maioria das amostras, o método LK mostrou valores mais elevados que os outros dois métodos, e o método LDA exibindo os menores valores. A fração caule exibiu teores mais elevados de lignina do que a folha; forrageiras maduras mostraram maiores concentrações de lignina do que plantas mais novas. Para quase todas as amostras, a digestibilidade in vitro da matéria seca foi negativamente correlacionada com os teores de lignina estimados pelos três métodos analíticos. O método LDA estimou razoavelmente bem a digestibilidade de forrageiras, seguindo-se a LPer. A LK não estimou bem a digestibilidade de gramíneas. Conclui-se que, nenhum dos três métodos foi totalmente satisfatório, sugerindo que a determinação analítica da lignina seja mais profundamente estudada. Este trabalho também quantificou as frações de carboidratos pelas equações da ″Cornell Net Carbohydrate and Protein System (CNCPS)″. A utilização da preparação parede celular (PC) nas equações da CNCPS, em substituição à fibra em detergente neutro (FDN), não proporcionou diferenças quanto aos teores de carboidratos de todas as frações. Porque foi realizada a comparação entre PC e FDN, foi descoberto que a equação da fração C, que estima os carboidratos indigeríveis da parede celular, pode ser simplificada, relacionando a fração indigerível em função do teor de lignina na matéria seca, e não em função da FDN, como é atualmente amplamente utilizado. Em outras palavras, o cálculo da fração indigerível da parede celular pode ser obtido independentemente da FDN isenta de cinzas e proteína. Como os valores da fração B1 (amido e pectina) pelo sistema CNCPS foram menores em relação à determinação laboratorial e com base nos resultados obtidos pelo emprego da PC nas equações de Cornell, sugere-se que a fração B2 seja destinada exclusivamente à pectina. E para os carboidratos digeríveis da parede celular, uma nova fração seja denominada, a B3 . Evidências colhidas na presente pesquisa sugerem que, pelas equações de Cornell, a pectina nunca esteve presente na fração B1 e sim na fração A. Portanto, do conteúdo da fração A, dever-se-ia subtrair o valor da pectina. A fração C continuaria inalterada e a fração B1 seria constituída apenas de amido / Lignin was quantified in five forage samples, in the fractions stem and leaf, at four maturity stages, through three analytical methods: acid detergent lignin (ADL), permanganate lignin (PerL) and Klason lignin (KL), all gravimetric procedures. The three techniques yielded different values for the same samples; in general, the KL method showed higher lignin concentrations than the two other methods, being the ADL which showed the lowest data. Stem fraction exhibited higher levels of lignin than leaf tissue; mature forages had higher concentrations of lignin than younger plants. For almost all the samples, lignin concentration was negatively correlated with the in vitro dry matter digestibility. The method ADL estimated reasonably well the digestibility of grasses, followed by PerL. The KL method was not a good predictor of digestibility of grasses. It was concluded that none of the three methods was totally satisfactory, suggesting that the analytical determination of lignin should be more deeply studied. This work also quantified the carbohydrate fractions through the Cornell Net Carbohydrate and Protein System (CNCPS). The utilization of crude cell wall instead of neutral detergent fiber in the CNCPS equations showed no differences in the estimates of all carbohydrate fractions. Because it was made a comparison between CW and NDF, it was discovered that the equation for the fraction C could be simplified where lignin expressed as a ratio of NDF, could be described on dry matter basis and not on NDF basis as it is largely used nowadays. In another words, estimate of indigestible cell wall could be obtained independently of ash + protein-free NDF. Because estimates of B1 fraction (starch and pectin) by means of CNCPS equations were lower than wet chemistry determinations and based on the results obtained by the substitution of NDF for PC in the Cornell equations, we suggest that B2 fraction be allocated exclusively for pectin. And for the digestible cell wall carbohydrates a new fraction, B3, be named. Evidences collected in the present experiment suggest that in the Cornell equations pectin was never part of B1 fraction but present in the A fraction. Thus, from the content of fraction A, pectin must be subtracted. The fraction C would remain unaltered and the fraction B1 would be constituted only by starch

Quantificou-se o teor de lignina em cinco amostras de plantas forrageiras, nas frações caule e folha, em quatro estádios de maturidade, através de três métodos analíticos: lignina detergente ácido (LDA), lignina permanganato de potássio (LPer) e lignina Klason (LK), todos de natureza gravimétrica. Os três métodos não foram concordantes entre si, sendo que para a maioria das amostras, o método LK mostrou valores mais elevados que os outros dois métodos, e o método LDA exibindo os menores valores. A fração caule exibiu teores mais elevados de lignina do que a folha; forrageiras maduras mostraram maiores concentrações de lignina do que plantas mais novas. Para quase todas as amostras, a digestibilidade in vitro da matéria seca foi negativamente correlacionada com os teores de lignina estimados pelos três métodos analíticos. O método LDA estimou razoavelmente bem a digestibilidade de forrageiras, seguindo-se a LPer. A LK não estimou bem a digestibilidade de gramíneas. Conclui-se que, nenhum dos três métodos foi totalmente satisfatório, sugerindo que a determinação analítica da lignina seja mais profundamente estudada. Este trabalho também quantificou as frações de carboidratos pelas equações da ″Cornell Net Carbohydrate and Protein System (CNCPS)″. A utilização da preparação parede celular (PC) nas equações da CNCPS, em substituição à fibra em detergente neutro (FDN), não proporcionou diferenças quanto aos teores de carboidratos de todas as frações. Porque foi realizada a comparação entre PC e FDN, foi descoberto que a equação da fração C, que estima os carboidratos indigeríveis da parede celular, pode ser simplificada, relacionando a fração indigerível em função do teor de lignina na matéria seca, e não em função da FDN, como é atualmente amplamente utilizado. Em outras palavras, o cálculo da fração indigerível da parede celular pode ser obtido independentemente da FDN isenta de cinzas e proteína. Como os valores da fração B1 (amido e pectina) pelo sistema CNCPS foram menores em relação à determinação laboratorial e com base nos resultados obtidos pelo emprego da PC nas equações de Cornell, sugere-se que a fração B2 seja destinada exclusivamente à pectina. E para os carboidratos digeríveis da parede celular, uma nova fração seja denominada, a B3 . Evidências colhidas na presente pesquisa sugerem que, pelas equações de Cornell, a pectina nunca esteve presente na fração B1 e sim na fração A. Portanto, do conteúdo da fração A, dever-se-ia subtrair o valor da pectina. A fração C continuaria inalterada e a fração B1 seria constituída apenas de amido / Lignin was quantified in five forage samples, in the fractions stem and leaf, at four maturity stages, through three analytical methods: acid detergent lignin (ADL), permanganate lignin (PerL) and Klason lignin (KL), all gravimetric procedures. The three techniques yielded different values for the same samples; in general, the KL method showed higher lignin concentrations than the two other methods, being the ADL which showed the lowest data. Stem fraction exhibited higher levels of lignin than leaf tissue; mature forages had higher concentrations of lignin than younger plants. For almost all the samples, lignin concentration was negatively correlated with the in vitro dry matter digestibility. The method ADL estimated reasonably well the digestibility of grasses, followed by PerL. The KL method was not a good predictor of digestibility of grasses. It was concluded that none of the three methods was totally satisfactory, suggesting that the analytical determination of lignin should be more deeply studied. This work also quantified the carbohydrate fractions through the Cornell Net Carbohydrate and Protein System (CNCPS). The utilization of crude cell wall instead of neutral detergent fiber in the CNCPS equations showed no differences in the estimates of all carbohydrate fractions. Because it was made a comparison between CW and NDF, it was discovered that the equation for the fraction C could be simplified where lignin expressed as a ratio of NDF, could be described on dry matter basis and not on NDF basis as it is largely used nowadays. In another words, estimate of indigestible cell wall could be obtained independently of ash + protein-free NDF. Because estimates of B1 fraction (starch and pectin) by means of CNCPS equations were lower than wet chemistry determinations and based on the results obtained by the substitution of NDF for PC in the Cornell equations, we suggest that B2 fraction be allocated exclusively for pectin. And for the digestible cell wall carbohydrates a new fraction, B3, be named. Evidences collected in the present experiment suggest that in the Cornell equations pectin was never part of B1 fraction but present in the A fraction. Thus, from the content of fraction A, pectin must be subtracted. The fraction C would remain unaltered and the fraction B1 would be constituted only by starch

A digestibilidade in vitro da matéria seca e da parede celular, de diferentes amostras vegetais arranjadas em três grupos: forragens, madeiras ou bambus, foi correlacionada com os teores de lignia estimados por três métodos analíticos. Os métodos empregados foram: lígnina em detergente ácido (LDA). lignina Klason (LK) e lignina permanganato de potássio (LPer). Os teores de lignina foram diferentes entre os métodos, para as mesmas amostras analisadas, sendo no geral maiores para LK e LPer. Para quase todas as amostras, os teores de lignina foram negativamente correlacionadas com a digestibilidade in vitro da matéria seca e da parede celular. O método LDA estimou razoavelmente bem a digestibilidade de forrageiras e bambus, seguindo-se a LPer. A LK não estimou bem a digestibilidade de gramíneas. Quanto às madeiras, nenhum dos três métodos foi um bom indicador da digestibilidade, mesmo o método LK, tradicionalmente usado para madeiras. Conclui-se que, nenhum dos três métodos foi totalmente satisfatório, sugerindo que a determinação analítica da lignina seja mais profundamente estudada. / The in vitro digestibility either dry matter or cell wall of different vegetable samples arranged in three groups: forages, wood or bamboos was correlated with lignin concentration determined through three analytical methods. The employed methods were: acid detergent lignin (ADL), Klason lignin (KL) and potassium permanganate lignin (PerL). Lignin concentrations were different among the methods for the same samples, generally larger for KL and PerL. For almost all samples, lignin concentration was negatively correlated with in vitro digestibility of dry matter and cell wall. ADL method predicted digestibility of grasses and bamboos reasonably well, followed by PerL. KL content was not a good predictor of grass digestibility. Concerning woods, none of the three methods was a good predictor of digestibilty, even the KL method, traditionally used for wood. It is concluded that none of the three methods was totally satisfactory, suggesting that analytical determination of lignin needs more research effort.

No description available.

Lignin, en av huvudkomponenterna i lignocellulosabiomassa, utgör en stor mängd av sidoströmen från massaindustrin. Lignin är aromatiska makromolekyler som förekommer i rikliga mängder i naturen och uppvisar unika antioxidant-, uv-skyddande, anti-ultravioletta, antikorrosiva och antimikrobiella egenskaper, etc. Ligninbaserade produkter är ännu inte kommersialiserade eftersom de är begränsade av den kemiska heterogeniteten hos lignin som separerats från olika råvaror och producerats i olika industriella processer. Istället förbränns lignin vanligtvis för värme- och elproduktion efter extraktion. Tillvägagångssätt för att bevara värdefulla egenskaper hos lignin och samtidigt övervinna begränsningar har blivit heta ämnen. I detta projekt genomfördes kemiska modifieringar av kraftlignin från olika naturliga råvaror, gran och eukalyptus, där fenolgrupperna ersattes av alkylgrupper med olika kedjelängder (kolnummer 1, 6 och 12). De kemiska strukturerna och de termiska egenskaperna hos kraftlignin studerades med en kombination av analytiska metoder. Egenskaperna hos två typer av tekniska kraftligniner och dess derivat undersöktes även för jämförelse. Resultaten visade att kemiskt modifierat lignin kan vara ett lovande råmaterial för förädlade produkter som till exempel ligninbaserade nanopartiklar. / Lignin, one of the major components in lignocellulose biomass, makes up a large amount of sidestream from the pulp industry. As an abundant feedstock of bio- originated aromatic macromolecules, lignin shows unique antioxidant, UV-protective, anticorrosive, and antimicrobial properties, etc. However, limited by the chemical heterogeneity of lignin separated from different bioresources and industrial procedures as well as its recalcitrance as macromolecules, lignin-based products are not yet commercialized, while lignin is commonly burnt for heat or power generation after extraction. Approaches of preserving valuable properties of lignin meanwhile overcoming limitations have become heated topics. In this project, chemical modifications of kraft lignin from different natural bio-origins, spruce and eucalyptus, were conducted, with alkyl groups of various chain lengths (carbon numbers 1, 6 and 12) substituting the phenolic groups. A combination of analytical methods for characterizing the chemical structures and thermal properties of kraft lignin and chemically modified kraft lignin were studied. Meanwhile, the characteristics of two kinds of technical kraft lignin and their derivatives were investigated for comparison. Results highlighted that chemically modified lignin could be a promising material to serve as a feedstock for value-added products such as lignin-based nanoparticles.

Call number: LD2668 .T4 1985 S38 / Master of Science

Production of bioethanol from crop residues such as wheat straw, has been considered as a viable approach to meet the ever increasing demands for energy without affecting our environment. However, lignin hinders the success of efficient production of bioethanol as it confers recalcitrance of lignocellulosic biomass to hydrolysis. Genetic modification of plant biomass lignin content or composition without affecting its agronomic functions, can reduce biomass recalcitrance, however, application of this strategy requires a detailed understanding of the molecular mechanisms underlying lignin synthesis. This thesis performed comprehensive analysis of the expression of wheat lignin biosynthesis candidate genes and identified genes that are predominant across different tissues. Using three commercial wheat cultivars that exhibit variation in stem resistance to lodging, it investigated the association of expression of these predominant genes with tissue lignin content. Furthermore, this identified transcriptional changes mediating the response of lignin biosynthesis in wheat to changes in soil moisture. / May 2015

Thesis (MSc)- Stellenbosch University, 2001. / ENGLISH ABSTRACT: Wood is composed of three main components: cellulose, hemicellulose and lignin. Cellulose is the main structural polymer, whereas the function of lignin in plants is to impart rigidity to the cells, to waterproof the vascular system, and to protect the plant against pathogens. A group of microorganisms, called white-rot fungi, are able to selectively degrade the lignin and hemicellulose from wood leaving the cellulose virtually untouched. The most widely studied fungus of this group is the basidiomycete Phanerochaete chrysosporium, which has become a model organism in studies of lignin degradation. Lignin is a large, heterogenous and water insoluble polymer and therefore the enzymes needed to degrade it have to be extracellular and non-specific. There are a number of enzymes that are involved in the degradation of lignin, including lignin peroxidases, manganese dependent peroxidases and laccases. Laecases are blue copper oxidases that require molecular oxygen to function, whereas lignin peroxidases and manganese peroxidases are heme proteins that require hydrogen peroxide. Phanerochaete chrysosporium has all three of these enzymes, as well as a system for producing the hydrogen peroxide that is necessary for peroxidases to function. For both scientific and industrial purposes, it is important to obtain linkage maps of the positions of genes in the genome of an organism. Most fungi, including P. chrysosporium, lack easily identifiable phenotypical markers that can be used to map the position of genes relative to each other on the genome. Previous methods of mapping genes in P. chrysosporium involved auxotrophic mutants, radioactivity, or the use of hazardous chemicals. Here we describe an automated DNA-sequencing based mapping technique that eliminates many of the problems associated with previous techniques. Portions of the genes to be mapped were amplified from homokaryotic single basidiospore cultures using gene specific primers using the polymerase chain reaction (PCR) technique. The PCR products were sequenced to determine the segregation of alleles. Two previously mapped lignin peroxidases, lipA and lipC, were used to develop this method, and the results obtained corresponded to the known genetic linkage. A newly characterised 13-glucosidase encoding gene from P. chrysosporium was also mapped. Linkage was found between the 13-glucosidase gene and a histone (Hl) encoding gene. In P. chrysosporium the lignin peroxidase isozymes are encoded by a family of at least ten genes. Previous studies with P. chrysosporium BKM-F-1767 in defined media, wood and soil have shown differential expression of the lignin peroxidase isozymes. In this investigation the levels of expression of lignin peroxidases in P. chrysosporium ME446 cultures grown in nitrogen or carbon limited defined liquid media, as well as on aspen wood chips were determined by competitive reverse transcriptase polymerase chain reaction (RT-peR). These results were compared to those previously obtained from P. chrysosporium BKM-F-1767 to evaluate strain specific variation in the expression of lignin peroxidases. The results indicate that, although there were many similarities in the patterns of lignin peroxidase expression, there were also enough differences to conclude that there were strain specific variations in the temporal expression of the lignin peroxidases. To conclude, a fast and cost effective method for mapping genes in P. chrysosporium was developed. Also, we showed that strain specific variation in temporal expression of lignin peroxidases occurs. / AFRIKAANSE OPSOMMING: Hout bestaan uit drie hoof komponente nl. sellulose, hemisellulose en lignien. Sellulose is die hoof strukturele polimeer, terwyl die funksie van lignin in plante is om die selle te versterk, die vaskulêre sisteem waterdig te hou, en die plant teen patogene te beskerm. 'n Groep mikroërganisms, bekend as witvrotswamme, kan lignien en hemisellulose selektief uit die hout verwyder, terwyl die sellulosevesels oorbly. Vanuit hierdie groep swamme is die meeste navorsing op die basidiomiseet Phanerochaete chrysosporium gedoen Lignien is 'n groot, heterogene polimeer en is onoplosbaar in water. Die ensieme wat benodig word om lignien afte breek is daarom nie-spesifiek en kom ekstrasellulêr voor. 'n Aantal ensieme is by die afbraak van lignien betrokke, insluitend lignienperoksidase, mangaanperoksidase en lakkase. Lakkase is 'n blou koperoksidase wat suurstof benodig vir aktiwiteit. Lignienperoksidase en mangaanperoxidase is heemproteïene en benodig waterstofperoksied. Phanerochaete chrysosporium het al drie van hiedie ensieme, sowel as 'n sisteem wat waterstofperoksied produseer. Vir beide wetenskaplike en nywerheidsdoeleindes is koppelingskaarte wat die posisie van gene in die genoom van 'n organisme aandui noodsaaklik. Die meeste swamme, P. chrysosporium ingesluit, het geen fenotipiese merkers wat maklik van mekaar onderskei kan word nie, en dit is dus moeilik om 'n kaart van die ligging van gene op die genoom te bepaal. Vorige metodes om gene in P. chrysosporium te karteer het auksotrofiese mutante, radioaktiwiteit of gevaarlike chemikalieë gebruik. Ons beskryf 'n metode wat van automatiese DNA-volgordebepaling gebruik maak en wat baie van die tekortkominge van die ou metodes oorkom. Dele van die gene is met geen-spesifieke PKR-amplifikasie uit kulture van homokariotiese enkel basidiospore verkry en die DNA-volgorde is bepaal om die segregasie van die allele te ondersoek. Twee gene waarvoor 'n koppelingskaart alreeds uitgewerk is, fipA en lipt), was gebruik om hierdie metode te ontwikkel. Die resultate stem ooreen met die bekende genetiese koppeling tussen hierdie gene. 'n Geen wat onlangs in P. chrysosporium ontdek is, nl. I3-glucosidase, is ook met hierdie metode gekarteer. Koppeling is met 'n histoon (Hl) geen gevind. Die lignienperoksidase isoensieme in P. chrysosporium word deur 'n familie van ten minste tien gene gekodeer. Vorige navorsing met P. chrysosporium BKM-F-1767 in gedefineerde media, hout en grond het getoon dat 'n variasie in die uitdrukking van lignienperoxidase isoensieme voorkom. In hierdie ondersoek is 'n kultuur van P. chrysosporium ME446 in stikstof- of koolstof-beperkende vloeibare media opgegroei, as ook op aspen houtblokkies. Die vlak van uitdrukking van die lignienperoksidases is deur middel van die omgekeerde transkripsie polimerasekettingreaksie (RT-PKR) bepaal. Die resultate vir P. chrysosporium ME446 is vergelyk met vorige resultate van P. chrysosporium BKM-F-1767 om te bepaal of stamspesifieke variasies in die uitdrukking van lignienperoksidases voorkom. Daar is 'n aanduiding dat, alhoewel soortgelyke patrone in die vlakke van lignienperoksidase uitdrukking voorkom, daar ook noemenswaardige verskille is. Hieruit kan afgelui word dat stamverwante variasie van lignienperokisdase uitdrukking voorkom. Ten slotte, ons het 'n vinnige, goedkoop metode om die gene in P. chrysosporium te karteer ontwikkel. Ons het ook bewys dat stam-spesifieke variasie in die uitdrukking van die lignienperoxidase gene voorkom.