Optimization of the culture conditions for the biomass production of the alga Phaeodactylum tricornutum was investigated in relation to chlorophyllase activity. To obtain the highest total chlorophyllase activity, the biomass of P. tricornutum was harvested after a period of 7 days of incubation during which the incubation temperature was maintained at 18°C for 18 h during the day and 10°C for 6 h during the night. During culture incubation, illumination was provided by fluorescent lamps projecting an incident intensity of 330 mumol/m2.s and the pH of the culture was maintained at 8.4, adjusted by a stream flow of CO 2. The hydrolytic activity of a partially purified chlorophyllase extract, obtained from the fresh biomass of P. tricornutum, was investigated in an aqueous/miscible organic solvent system containing refined bleached deodorized (RBD) canola oil, and chlorophyll or pheophytin as substrate. The effect of a wide range of oil contents, chlorophyll and pheophytin concentrations, acetone concentrations, incubation temperatures and agitation speeds on the enzyme activity was studied. The optimum reaction conditions for chlorophyllase biocatalysis were determined to consist of 20% oil, 10% acetone and a 200 rpm agitation speed with optimum temperatures and substrate concentrations of 35°C and 12.6 muM for chlorophyll, and 30°C and 9.3 muM for pheophytin. The presence of RBD canola oil showed an inhibitory effect on chlorophyllase activity whereas acetone acted as an activator at low concentrations and an inhibitor at higher ones. Moreover, chlorophyllase showed a limited affinity towards pheophytin as substrate compared to that obtained for chlorophyll. Selected samples of crude commercial canola oil were analyzed for their green pigment content using high-performance liquid chromatography and chlorophyllase biocatalysis was investigated on eight varieties of crude commercial canola oil. The chlorophyllase activity was lower in th
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.78248 |
| Date | January 2003 |
| Creators | Bitar, Marianne |
| Contributors | Kermasha, Selim (advisor) |
| 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 | Master of Science (Department of Food Science and Agricultural Chemistry.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001985484, proquestno: AAIMQ88156, Theses scanned by UMI/ProQuest. |
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