| Summary: | 碩士 === 國立臺灣海洋大學 === 水產養殖學系 === 104 === Rhodomonas sp. cultivated under white light intensity of 30 μmol photons m-2 s-1, and 24℃, resulting the best biomass of 106 cells/ml. Increasing the sodium nitrate concentration of the medium can enhance the phycoerythrin content of R. sp. Phycoerythrin of R. sp. was extracted under pH 6.8 phosphate buffer without repeated freezing and thawing steps, and then using 90% ammonium sulfate saturation can precipitate the most yield of the phycoerythrin. Phycoerythrin yield of desalted groups were about 190 mg/g (dry weight per gram), in contrast those without desalted groups were about 805 mg/g. By the way, re-extracting the precipitation can obtain another 4.32 μg/g of chlorophyll a and 0.30 μg/g of chlorophyll c2. The type of phycoerythrin of R. sp. is PE-545. Under SDS-PAGE found that the phycoerythrin was composed by ca. 10 kDa of α subunit and ca. 20 kDa of β one. Furthermore, Phycoerythrin of R. sp. was stable within the range of pH 5-8 and low temperature (4℃-25℃), and 24 hrs of illuminated resulting only 20% of phycoerythrin degradation, that was insensitive to light. It also has little DPPH scavenging and reducing capabilities. The ultrastructural appearance of the studied microalga was similar to R. salina, but with some differences. Therefore, it was temporarily classified as R. sp. or R. salina Keelung var. Finally, using sodium alginate and polyvinyl alcohol-sodium alginate to immobilize the R. sp. to be algal beads, found both methods that can as the “seed stock” for long-term storage.
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