The cellulase enzyme system of the fungus Trichoderma reesei Rut C-30 was fractionated by DEAE ion exchange chromatography into four groups according to their substrate specificity. By analytical isoelectric focusing and activity stains it was revealed that fraction EGI is comprised of endoglucanases specific to cellulosic substrates, and that fractions EGII and EGIII are non-specific endoglucanases that hydrolyze cellulose as well as xylan substrates. The major protein fraction CBHI was shown to be a cellobiohydrolase. Turbidimetric measurement phase contrast microscopy and analysis of the products resulting from the hydrolysis of swollen cellulose demonstrated differences between endoglucanases and cellobiohydrolases. The enzyme component CBHII, previously described as a cellobiohydrolases was shown to be an endoglucanase. / The adsorption behavior of the four enzyme fractions was examined, with respect to pH, temperature and ionic strength. This was accomplished by using ($ sp3$H) radiolabeled cellulase fractions as tracers. The adsorption of the cellulases occurred within 60 minutes, and was described by a Langmuir type correlation. Increasing the adsorption temperature increased the saturation uptake of the endoglucanases but not of the cellobiohydrolases. Changes in pH and ionic strength affected both the degree and strength of adsorption of all the fractions, likely due to protein structure conformational changes. / Direct evidence of exchange between adsorbed and free enzymes was obtained for each component using ($ sp3$H) and ($ sp{14}$C) radiolabeled tracers. In simultaneous adsorption of enzyme pairs, CBHI was shown to predominate adsorption. Endoglucanase EGI was preferentially adsorbed over EGII and EGIII. Sequential adsorption studies have shown that interaction between enzyme components largely determine the degree of their adsorption. Evidence suggested both common and distinct adsorption sites exist, and that their occupation depends on which components are involved. / Light microscopy and monitoring of sugar production during cellulose hydrolysis indicated that conditions which limit predominance in adsorption by any one of the cellulase components, enhance synergism and increase degree of hydrolysis.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.75770 |
| Date | January 1987 |
| Creators | Kyriacou, Andreas |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 000660380, proquestno: AAINL46153, Theses scanned by UMI/ProQuest. |
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