ISOLATION, CHARACTERIZATION, AND MODIFICATION OF BIOSILICA FROM NAVICULA SP. NTL1 WITH THIOL GROUP

• Main Author: Maghfirah, Ikramah
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/47658
• Institution: Institut Teknologi Bandung

Navicula sp. NTL1 is a tropical Indonesian sea diatom, which has a cell wall structure of silica (biosilica) with nanometer-sized pores. Biosilica surface can be modified with thiol groups to alter its properties, such as the hydrophobicity, adsorption, adhesion, hydrophilicity, dielectric constant, and conductivity which are useful for drug delivery system, catalysts, and heavy metal adsorption. In this study, the biosilica of Navicula sp. NTL1 was modified with thiol group of MPTMS (3-mercaptopropyl-trimethoxy-xilane). The research methods include cultivation of Navicula sp. NTL1 by Batch method, harvesting by sentrifugation, isolation of biosilica by washing with 65% HNO3, activation and modification of biosilica by MPTMS, and characterization of modified biosilica by FT-IR and SEM-EDS. The results showed that the cell morphology of Navicula sp. NTL1 is oval, bilaterally symmetrical, yellowish brown in color, with the length of cell of ± 13–17µm. Cell density increased from the initial density if 1,0 × 106 cells/mL to reach its maximum density of 3,4 × 106 cells/mL on the fifth day. The maximum growth rate was obtained on fourth day at 8,0 × 105 cells/mL. Biomass productivity of Navicula sp. NTL1 for 170 L culture that planted for two weeks is 0,12 g/L/day. The biosilica obtained was yellowish, which turned white upon calcination, indicating the removal of organic compounds. Productivity of biosilica Navicula sp. NTL1 is 4,12 mg/L/day. The modified biosilica was characterized with FT-IR and resulting peak at 2929 cm-1 indicating –CH of the propyl goup of MPTMS. EDS data shows the peak of sulfur (S) of 0,16% atom, indicating that the biosilica was modified with thiol group.