Literature searches were made with respect to the metabolites produced by species under consideration as biological control agents and other species of the same genera. Literature analytical methods were selected and developed to profile the organic solvent extracts of the selected fungi grown in standard media and to screen for specific metabolites by thin layer chromatography - mass spectrometry. From these screenings attempts were made to characterize specific components. Important classes of metabolites that might be expected to be produced by the candidateorganisms were identified from consideration of species believed to be related genetically through morphology and isozyme analysis. These include trichothecene-, cyclopentenylisocyanide-, and gliotoxin-type secondary metabolites and the peptaibol polypeptides. Screening of the candidate species demonstrated that these produce many metabolites, the profiles of which depend on the substrate on which they are grown. Few metabolites are readily identifiable on the basis of mass spectral data or retention indices alone. The Trichoderma strains were shown to produce dehydroacetic acid, a known antifungal agent, in defined media. T. viride EL3 was also shown to produce this metabolite on jack pine sapwood. All the Gliocladium strains of interest were shown to produce the Aib marker indicating the production of peptaibol antibiotics (mycotoxins). This is the first report of this type of metabolite for Gliocladium solani. For Gliocladium viride EL8 the production of 3,6-dibenzylpiperazine-2,5-dione was demonstrated. This indicates that this strain may have the potential to biosynthesize gliotoxin or related metabolites depending on culture conditions. The similarity between some of the metabolites reported to be produced by the genera under consideration as biocontrol agents and those reported to be produced by staining fungi may have implications with respect to the mechanisms of biocontrol.
Assessment of the properties of lignocellulosic materials prior to and after pretreatment and enzymatic modification is important in determining the commercial potential and feasibility of the processes. The effect of treatments on the degree of polymerization (D.P.) of cellulose and carbohydrate composition are particularly important in the evaluation of treatments of commercial pulps with enzymes. Improved understanding of the effect of pretreatment conditions and subsequent treatments on D.P. of cellulose in the substrates will aid in development of a more efficient enzymatic hydrolysis process. The determination of the D.P. of cellulose in pretreated forestry residues will also aid in the identification of alternative polymeric products. A method was developed for determining the molecular weight distribution of lignocellulosic materials. The method of choice was derivatization of the substrate to the carbanilate followed by size exclusion chromatography. A number of possible variables in the method were investigated and a microscale procedure developed. This procedure was used to provide molecular weight distribution data for both softwood and hardwood pulps subjected to xylanase treatments. The method was also used to study the effects on the cellulose in aspenwood and sprucewood of differing steam pretreatment conditions, and post treatments (hydrogen peroxide). These studies highlighted the limitations of the method when analyzing lignocellulosic materials with significantly higher lignin contents than the pulps for which it was originally intended. More importantly, the studies indicated that depending on the treatment conditions used, celluloses of substantially different average D.P. and polydispersity can be produced. Analysis of carbohydrate in lignocellulosic materials continues to be critical to any study involving residue utilization by bioconversion. Development of methods for HPLC analyses of carbohydrates were monitored with emphasis on the use of electrochemical detection methods. The state-of-development of these detectors is discussed.
