ABSTRACT
UTILIZATION OF SCYTALIDIUM THERMOPHILUM PHENOL OXIDASE IN BIOORGANIC SYNTHESES
Kaptan, Yelda
M.S., Department of Biotechnology
Supervisor: Prof. Dr. Zü / mrü / t B. Ö / gel
Co-supervisor: Prof Dr. Ufuk Bakir
September 2004, 90 pages
In this study, the ultimate aim was to utilize phenol oxidases of Scytalidium thermophilum in bioorganic syntheses. For this purpose, studies were conducted towards enhancing the production of phenol oxidases by Scytalidium thermophilum, developing a suitable method for laccase activity assays, analyzing the effects of organic solvents on phenol oxidase activity and analysis of the biotransformation of a number of organic substrates by phenol oxidases of Scytalidium thermophilum. In order to enhance the production of phenol oxidases, induction experiments were carried out with gallic acid, syringaldazine and chlorogenic acid. Gallic acid was found as the most effective inducer for phenol oxidase production. Inductive effect of edible mushroom Agaricus bisporus was also assayed, however, the phenolic compounds released by mushroom did not represent any induction for phenol oxidase activity of Scytalidium thermophilum. Different substrates were tested and catechol was determined as the most suitable substrate rather than syringaldazine and ABTS. Molar extinction coefficient (e) of catechol was calculated as 3450 M-1 cm-1 and 3700 M-1 cm-1 by using &ldquo / substrate blank&rdquo / and &ldquo / enzyme blank&rdquo / respectively at 420 nm. Kinetic parameters, Km and Vmax for the enzymatic reactions in which catechol was used as substrate were calculated as 52.03 mM and 0.253 U/ml respectively from Lineweaver-Burk plot and as 41.25 mM and 0.2055 U/ml from Hanes-Woolf plot. Effect of some organic solvents on phenol oxidases of Scytalidium thermophilum was assayed and DMSO was found as an appropriate solvent for the organic substrates. Phenol oxidase containing culture supernatant could oxidize benzoin, hydrobenzoin and benzoyl benzoin.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/2/12605353/index.pdf |
| Date | 01 September 2004 |
| Creators | Kaptan, Yelda |
| Contributors | Ogel, Zumrut Begum |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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