Study of Extracellular Carbohydrate from the Tropical Marine Microalgae Navicula sp.

• Main Author: Hajjar Rakhmadumila, Deby
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/37901
• Institution: Institut Teknologi Bandung

Lipids for biodiesel feedstock, pigments for dye sensitized solar cell, and biosilicas for zeolite synthesis from the tropical marine microalgae Navicula sp. have been studied. However, carbohydrate produced by Navicula sp. has not been studied yet. Therefore, the present research identifies carbohydrates secreted out from Navicula sp., or called extracellular carbohydrates. Extracellular carbohydrates of Navicula sp. are used to protect the cell surfaces and to facilitate the absorption of nutrients. The research methods included the cultivation of microalgae, isolation of extracellular carbohydrate, assay of carbohydrate (anthrone test, Molisch test, picrate test, and iodine test), and identification of carbohydrate using FTIR spectroscopy and SEM-EDS. The results showed that Navicula sp. cultures (900 mL) with an initial cell density of 100,000 cell/mL for 9 d produced 3.7328 ± 0.0776 g wet biomass. The dried Navicula sp. biomass which is burned in the TGA apparatus released 22.9% carbondioxide. The extracellular carbohydrate of Navicula sp. was in the form of brown gel with yield of 5% (w/w). The carbohydrate assays to the brown gel showed positive results to the anthrone test and Molisch test, negative results to the picrate test and iodine test indicating brown gel of Navicula sp. was long chain carbohydrate with no helical structure. The extracelluar carbohydrate of Navicula sp. showed hydroxide group in the wave number range of 3294?3402 cm?1 and acetal group in the wave nuber range of 1043?1076 cm?1. The extracelluar carbohydrate of Navicula sp. was amorphous with rough surface textures and highly carbon and oxygen content. Thus, brown gel of Navicula sp. was extracellular carbohydrate.