CHARACTERIZATION OF LEVAN PRODUCED BY HALOPHILIC BACTERIA \\TEXTIT{BACILLUS LICHENIFORMIS} BK1 AND ITS APPLICATION FOR PROTEINS CARRIER NANOPARTICLES

• Main Author: Oktavia, Ira
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/71575
• Institution: Institut Teknologi Bandung

Levan is a fructoligosacharide (fructan) biopolymer that can form a linear chain structure in which each monomer of fructose linked with glycosidic ?-(2,6) bond and it can form a branched chain with glycosidic ?-(2,1) bond. Levan is a product of transfructocylation and polymerization reactions catalyzed by levansucrase (EC 2.4.1.10) with sucrose as a substrate. The research about levan applications are still intensively studied because of the levan charachteristics that are non toxic, biodegradable, high biocompatibility, and nonalergic make it suitable to be applied in various industrial sectors, such as food, cosmetic, and drug industries. In additon, levan is currently being developed as a meterial for nanoparticle in the field of nanotechnology. Bacillus licheniformis has been known as levanproducing bacteria. In this study, the moderate halophilic bacteria Bacillus licheniformis strain BK1, which was isolated from salt water Bledug Kuwu mud, Grobogan, Purwodadi Central Java, was explored its potential as a levanproducing bacteria. Proof of this bacterium as a levan producer was revealed by growing the bacteria on a Belghith media (levan medium) that contains sucrose as the carbon source. The bacterial colonies secretes viscous fluid after 24 hours incubation indicating the positive results as a levan producer. The optimization medium for levan production was performed by observing levansucrase activity, where the highest activity of levansucrase was achieved on the medium contained 15% sucrose, 7.5% NaCl, pH 8, 40 oC and 16 hours of the incubation time. Levan produced by the bacteria, is verified its structure by using FTIR (Fourier Transform Infrared) and NMR (Nuclear Magnetic Resonance). The FTIR spectrum revealed high similiarity of the sample analyzed with the standard of levan, in which the vibration peak of -OH bond at 3388,93cm-1, -CH bond at 2885,51cm-1, C-OH bond at 1018,41cm-1, furanosa ring at 1056,99–1271,09 cm-1, and the fingerprint area at 927,76–1271,09 cm-1. The result of H-NMR analysis was further verified that sample is levan chemical shift of the H-NMR of 3,64 (d, H-1a) ppm; 3,73 (d, H-1b) ppm; 4,15 (d, H-3) ppm; 4,06 (t, H-4) ppm; 3,89 (m, H-5) ppm and 3,60 (t, H-6) ppm, while at C-NMR of 60,09 (C-1) ppm; 104,27 (C- 2) ppm; 76,38 (C-3) ppm; 75,26 (C-4) ppm; 80,35 (C-5) ppm and 63,44 (C-6) ppm. After the sample was verified as levan, then we extend our study by exploring its potential as a material for nanoparticle. In this study levan nanoparticle was used to immobilized some proteins. Bovine Serum Albumin (BSA) and lysozyme were used as the proteins targets for the immobilization. Theresult of BSA and lysozyme immobilization gave respective efficiency (% EI) about 74,62% and 81,77%. The immobilized particles were further characterized by using SEM (Scanning Electron Microscopy). The SEM image of BSA contaning particle showed mostly nonspherical shape with the size distribution was about 83–298 nm. In contrast lysozyme containing particle were mostly spherical and more uniform in the size distribution which was about 206–285 nm. The differences in nanoparticle morphologies wre likely caused by the different on proteins size and average lenght of levan chain. Levan produced by B. Licheniformis BK1 was likely too short to encapsulate whole BSA molecule resulting the irregular shape of the resulted nanoparticle compared to when it was used to encapsulate lysozyme that has smaller molecular weight than BSA. When BSA immobilization was repeated by using a standard levan that has a longer chain, the resulted BSA containing particle was more spherical with the size distribution was about 63–228 nm and gave efficiency about 85,46%, thereby veryfing the important of molecular size of levan to the morphology of the resulted nanoparticle.Halophilic bacteria, Bacillus licheniformis BK1, levan, protein immobilization, nanoparticles