EFFECTS OF NITROGEN SOURCES IN GROWTH MEDIUM ON PHOTOSYNTHETIC PIGMENTS Thalasiossira sp.

• Main Author: HASANELA (NIM : 20514043) , NURANI
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/20367
• Institution: Institut Teknologi Bandung

In spite of producing chemicals for biodiesel and bioethanol, microalgal biomass contains valuable chemical compounds such as photosynthetic pigments that are not explored. Diatom grows rapidly in medium containing nitrogen posessing an important role in enhancing biomass and activity of cell metabolism. The research aimed to study the effects of nitrogen sources in growth medium on the productivity of photosynthetic pigments of Thalassiosira sp. cultivated indoor and outdoor photobioreactors. The methods included cultivation of Thalassiosira sp. cells in medium containing nitrate or urea under two different conditions (indoor and outdoor), harvesting the biomass, isolation of photosynthetic pigments, purification the pigments using silica column chromatography, characterization of photosynthetic pigments by TLC and UV–Vis spectrophotometer. The result showed that dried biomass of Thalassiosira sp. obtained from culture in medium containing nitrate or urea indoor with an initial cell density of 5 × 105 cells mL–1 was 0.21±0.11 and 0.15±0.06 g L –1 , respectively, meanwhile, from the oudoor culture was 258.50±6.89 dan 290.65±56.08 mg L –1 , respectively. Photosynthetic pigments identified from crude extract of Thalassiosira sp. cultivated in medium containing nitrate indoor were β-carotene, pheophytin a, chlorophyll a, diadinochrome, fucoxanthin, and chlorophyll c, with chlorophyll and carotenoid productivities of 12.98 dan 11.15 µg L –1 h –1 , respectively. Unlike the results indoors, pigment of diadinochrome was unidentified from purifications products of crude extract of Thalassiosira sp. cultured medium containing urea indoor, and chlorophyll and carotenoid productivities of 38.54 and 29.11 µg L –1 h –1 , respectively. Thalassiosira sp. cells cultured in medium containing nitrate outdoor produced photosynthetics pigments: β-carotene, pheophytin a, chlorophyll a, diadinoxanthin, fucoxanthin, chlorophyll c with chlorophyll and carotenoid productivities of 103.85 and 70.93 µg L –1 h –1 , respectively. While diadinoxanthin pigment was unidentified in Thalassiosira sp. cells cultured in medium containing urea outdoor, and chlorophyll and carotenoid productivities of 138.25 and 100.52 µg L –1 h –1 , respectively. Thus, Thalassiosira sp. cells cultures in urea medium showed higher pigment productivity compared to those in nitrate medium.