CHARACTERIZATION OF EXTRACELL CARBOHYDRATE FROM TROPICAL MARINE MICROALGAE NANNOCHLOROPSIS SP.

• Main Author: Febryawati, Vira
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/33899
• Institution: Institut Teknologi Bandung

Past research has shown that tropical marine microalgae Nannochloropsis sp. can be utilized as a producer of lipid and biopigmen. Microalgae Nannochloropsis sp. also known to produce carbohydrates, but has not been widely reported. This study aimed to characterize extracell carbohydrate produced by Nannochloropsis sp.. Stages of research undertaken include the preparation of Nannochloropsis sp. biomass, isolation of extracell carbohydrate Nannochloropsis sp., and physicochemical characterization of extracell carbohydrates obtained. From the initial cell density of 106 cells/mL, the average cell density after cultivated for 8 days is 16.301 ± 2.59 x 106 cells/mL with a density of Nannochloropsis sp. biomass is equal to 2,0748 ± 0,24 g/L. Cell of Nannochloropsis sp. is absorb CO2 and then converted into biomass. TGA analysis showed that dry biomass of Nannochloropsis sp. decomposes at a temperature of 162 – 617,5 oC by releasing gas about 52% which estimated come from carbohydrates, lipids, and proteins. This fact shows that CO2 has been absorbed and converted by Nannochloropsis sp. into biomass, because the only one source of carbon available in the medium is CO2. Extracell carbohydrate analysis using SEM showed that the surface of the extracell carbohydrate Nannochloropsis sp. has a rough texture. Molisch and Anthrone test against extracell carbohydrates give positive results marked by the formation of the purple rings (Molisch test) and the formation of a bluish green color (Anthrone test). Iodine and picric test on extracell carbohydrate gives a negative result, marked by the absence of color changes, indicating that extracell carbohydrate of Nannochloropsis sp. not helical and do not have a reducing group. EDS analysis on extracell carbohydrate indicate the elements carbon and oxygen. Infrared characteristic of extracell carbohydrate Nannochloropsis sp. characterized by the absorption of the hydroxy group (– OH) at wavenumber from 3388,93 to 3290,56 cm-1 and absorption acetal group at 1153,43 cm-1. These results indicate that extracell carbohydrate from microalgae Nannochloropsis sp. has a surface with rough texture, not helical and do not have a reducing group, indicating that the molecule may be a oligosaccharide.