No description available.

Thesis (M.S.)--University of Wisconsin--Madison, 1981. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 53-57).

No description available.

Heterobasidion annosum (Fr.) Bref., is a pathogenic hymenomycete which causes white-rot of coniferous trees throughout temperate regions of the Northern Hemisphere. The fungus can be divided into three intersterility groups (IS-groups) in Europe and two IS-groups in North America based on in vitro sexual compatibility and, loosely, on host tree preference. European P, S and F IS-groups prefer pine, spruce and fir respectively, and North American P and S groups prefer pine and fir respectively. This work describes the identification of discriminating characters which reflect underlying genetic differences accumulated between the IS-groups. Two genetic loci in the ribosomal DNA repeat and RFLPs in total genomic DNA were examined. Intraspecific divergence was found in the DNA sequence of PCR amplified internal transcribed spacer region (ITS) in ribosomal RNA repeat unit. It was found that various mutation detection techniques such as RFLP, single strand DNA conformation polymorphism (SSCP), heteroduplex DNA polymorphism and amplification refractory mutation system (ARMS) were applicable for the detection of base variations in the ITS region and therefore for the identification of IS-groups. However, since European S and F strains are genetically closely related to each other, these two were not unequivocally distinguishable. Intergenic spacer region (IGS) in the rRNA repeat unit in H. annosum was also amplified by PCR. The five IS-groups were distinguished by RFLP analysis of the IGS region, though there remained some European S and F group isolates which were also identical at this locus. RFLP in total genomic DNA was seen on ethidium bromide stained agarose gel after electrophoresis and found to be able to differentiate the European IS-groups unambiguously. RFLPs in total genomic DNA revealed with minisatellite probes were also found to be useful for IS-group identification.

Natural organic matter (NOM), a complex mixture of organic compounds, influences drinking water quality and water treatment processes. The presence of NOM is unaesthetic in terms of colour, taste and odour, and may lead to the production of potentially carcinogenic disinfection by-products (DBPs), as well as biofilm formation in drinking water distribution systems. Some NOM removal processes such as coagulation, magnetic ion exchange resin (MIEXTM) and membrane filtration produce sludge and residuals. These concentrated NOM-containing sludges from alum precipitation, membrane treatment plants and MIEX regeneration must therefore be treated prior to disposal. The white-rot fungi possess a non-specific extracellular oxidative enzyme system composed of lignin peroxidase (LiP), manganese-dependent peroxidase (MnP) and laccase (Lac) that allows these organisms to mineralise lignin and a broad range of intractable aromatic xenobiotics. Rojek (2003) has shown the capabi lity of Phanerochaete chrysosporium ATCC 34541 to remove 40-50% NOM from solution, however, this was found to be mainly due to adsorption and to be a partially metabolically linked activity. Consequently, the bioremediation of NOM wastes by selected white-rot fungi was further investigated in the present study. The P. chrysosporium seemed to preferentially remove the very hydrophobic acid (VHA) fraction, and so was most effective for a NOM preparation with a high proportion of hydrophobic content (and so high in colour and specific UV absorbance (SUVA)). The extent of NOM decolourisation by P. chrysosporium in three growth media with different C:N ratios followed the trends: Waksman (C:N = 6) > Fahy (C:N = 76) > Fujita medium (C:N = 114), such that the lower the C:N ratio, the greater NOM removal. This was consistent with the findings of Rojek (2003), who used a different NOM preparation and demonstrated that the removal of NOM increased with decreased C:N ratio (1.58-15.81). As removals of NOM with P. c hrysosporium ATCC 34541 were low, and little biodegradation occurred, this organism was compared with P. chrysosporium strain ATCC 24725, Trametes versicolor ATCC 7731, and three strains of yeast (Saccharomyces species arbitrarily denoted 1, 2 and 3). T. versicolor gave the greatest removal (59%) which was attributed largely to degradation, whereas the NOM removal by the two strains of P. chrysosporium (37%) and the yeast was predominantly due to adsorption as indicated by the deep brown colouration of the biomass. Saccharomyces sp. 1, 2 and 3 removed 12%, 61% and 23% of the colour, respectively. Although Saccharomyces sp. 2 had similar high colour reduction to T. versicolor, the specific removal values differed markedly: 0.055 compared to 0.089 mg NOM/mg biomass, respectively. The low level of the ligninolytic enzymes secreted by both strains of P. chrysosporium corresponded with the low degree of NOM removal by biodegradation as shown by high performance size exclusion chromatography (HPSEC). The high NOM removal attained by T. versicolor was attributed to the activities of the ligninolytic enzymes, especially laccase. The NOM removal was attributed to the breakdown of the high molecular weight compounds to form a pool of low molecular weight materials, which were then most likely utilised by the T. versicolor. Growth of T. versicolor cultures at 36oC caused inhibition or denaturation of the activity of the phenoloxidase enzymes compared to those grown at 30oC. The low activity of LiP in both cultures suggested that this enzyme may not play much of a role in NOM removal. The higher levels of MnP and Lac activities at 30oC were responsible for the greater NOM removal (73% vs. 59%) and thus the cleavage of aromatic rings, conjugated and C-Cβ αbonds in phenolic moieties, as well as catalysing alkyl-aryl cleavage in the NOM structures. T. versicolor cultured in Waksman medium with higher initial glucose (5 g/L cf. 2 g/L) led to lower ligninolytic enzyme activities and a lower degree of NOM removal (25% less colour reduction), probably due to preferential use of glucose over NOM as carbon source. NOM removal (mg removed) increased linearly with NOM concentration up to 600 mg C/L (62 mg (A446); 31 mg (A254)), above which removal decreased markedly. This trend coincided with increasing total ligninolytic enzyme activity, where the level of Lac increased up to 600 mg C/L NOM although MnP decreased gradually across the range while LiP was only detected for 100 and 300 mg C/L NOM. Hence, the removal of NOM from solution by T. versicolor was associated with high oxidative enzyme activity, particularly of laccase. Laccase was the major extracellular enzyme secreted by T. versicolor and by deduction, played a major role in NOM removal. The optimum temperature for Lac activity secreted by T. versicolor cultured in Waksman medium supplemented with 4.5 g/L wheat bran plus 0.5% Tween 80 was determined to be 50oC. The optimum pH for the Lac activity for guaiacol and NOM was identified as pH 4.0-4.5. Although the optimum enzyme activity occurred at 50oC, 30oC was recommended for enzymatic removal of NOM as the phenoloxidase enzyme activity may be denatured if the NOM removal process were considered to run for long period at high temperature. Although agitation led to apparent enzyme denaturation, fermentations with continuous agitation promoted enzyme activity faster than those with occasional agitation (agitated every 6 hours for 30 minutes at 130 rpm and 30oC) as it provides better mass transfer. However, it seemed that continuous agitation had an adverse effect on the fungal growth and enzyme production over extended fermentation periods. Addition of 4.5 g/L wheat bran to modified Waksman medium in the absence of NOM led to high production of Lac activity compared with LiP and MnP activities, showing its great potential as a laccase inducer. Addition of Tween 80 alone to the cultures led to a small improvement in Lac activity; however, with the presence of wheat bran it caused marked increases in LiP, MnP and Lac activit ies. When NOM was added to cultures of T. versicolor with the two supplements, it led to markedly reduced Lac activity, but increased LiP and MnP activities, and no improvement in NOM removal compared with the cultures in the absence of supplements (12 mg (or 61%) cf. 15 mg (or 73%) for 100 mg C/L after corrected for colour from and adsorption by wheat bran).

The idiophasic production of nonspecific extracellular enzymes by the Basidiomycete fungus Phanerochaete chrysosporium, referred to as the ligninolytic system, has been reported by many researchers to be capable of degrading a broad spectrum of environmentally persistent compounds including some alkyl halide chemicals. Cultivation of the fungus and the ability of the ligninolytic system to degrade the alkyl halide pesticide toxaphene were explored in pure liquid cultures. The effects of culture growth temperature and toxaphene concentration were evaluated. The extent of toxaphene conversion with time was determined using three different indicators; toxaphene gas chromatographic elution patterns, the determination of free chloride concentrations by ion chromatography analyses, and the distribution of chloride in aqueous and biomass fractions via total organic halide analyses. Oxidation of the azo dye, Orange II, via spectrophotometric measurements was employed to determine the activity and reactivation of the fungal ligninolytic system. Degradation of toxaphene in the P. chrysosporium cultures was limited, with a maximum of 7% of the original mass of chloride originating from the toxaphene being released over a three week period. The main removal mechanism of the toxaphene from solution was observed to be adsorption to the mycelium biomass. Ligninolytic activity was equally active at temperatures less than optimum for maximum growth of the fungus which implies that the ligninolytic system can be effective with reduced temperature requirements. Elevated pH conditions did not effect ligninolytic activity indicating that high more neutral pHs, which are characteristic of soil properties, do not inhibit ligninolytic activity. Reactivation of the ligninolytic system was accomplished in a nonimmersed liquid culture system. The immobilized configuration appeared to be an effective system for cultivating the ligninolytic system on a continuous basis. / Master of Science

No description available.

Hydrothermal liquefaction is a thermochemical technique for obtaining crude bio-oil from lignocellulosic biomass with moderate temperature and pressure. The crude bio-oil can then be upgraded to various biofuels and bioproducts. Hydrothermal liquefaction is amenable to use of biomass feedstocks that have high-moisture. The overall goal of this research is to demonstrate the effectiveness of white rot fungus (WRF) as a pretreatment option in the production of bio-oil from switchgrass through hydrothermal liquefaction. If WRF is an effective pretreatment, it could be a cost-effective option for commercialization, allowing hydrothermal liquefaction to be used on an industrial scale to produce high quality bio-oil capable of replacing some of the fossil fuel liquids used today. This thesis specifically focuses on the investigation of the effects of particle size and culture time on lignin degradation using Phanerochaete chrysosporium as a pretreatment method on switchgrass. In addition, the conversion efficiency of WRF treated switchgrass was compared to that of torrefied switchgrass and untreated switchgrass after the pyrolysis conversion process. The results indicate that WRF outperforms torrefaction as a pretreatment method for the conversion of sugar-based components, thus may be an attractive alternative for fermentation conversion processes, but probably not for thermochemical processes.

Thesis (M. Sc.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (leaves 115-130). Also available via the World Wide Web.

This dissertation is composed of two research projects. The first research project is aimed at using synthetic fluorogenic probes to study the possible or dominant linkages in biomass. These probes that mimic the linkages found in lignin-cellulosic biomass are designed to select the optimal fungi from direct evaluation process or could be tested against other microbials to screen candidates which can break ligno-hemicellulose bonds. For the first stage, these probes would be tested against white rot fungi extract. The white rot fungi are used for the first stage to see if releasing or degrading carbohydrates while keeping lignin largely intact is possible or not. These probes can help to answer fundamental questions, such as what could be the dominant linkages between lignin and hemicellulose, and what are the possible mechanisms for the cleavage of carbohydrates in biomasses. Understanding the linkages in these biomass will enable high efficient degradation or release of carbohydrates, primarily hemicelluloses, from biomass. The second project is focused on synthesizing new aminoglycoside analogs and exploring the potential to revive traditional antibacterial kanamycin as new types of antifungal agents. Aminoglycosides are widely used broad spectrum antibiotics. Although mainly used as antibacterial agents, there have been studies to show amphiphilic aminoglycoside derivatives could be possibly employed as antifungal agents. A concise and novel method for site-selective alkylation of tetra-azidokanamycin has been developed that leads to the divergent synthesis of three classes of kanamycin derivatives. These new amphiphilic kanamycin derivatives bearing alkyl chains length of 4, 6, 7, 8, 9, 10, 12, 14，16 have been synthesized and tested against bacteria and fungi. Surprisingly, the antibacterial effect of the synthesized kanamycin derivatives decline or disappear compared with the original kanamycin A, but some of the compounds show very strong activity as antifungal agents.