Production, Purification and Characterization of Levan Isolated from Bacillus subtilis

¹ Faculty of Applied Medical Sciences, Department of Clinical Laboratories, University of Kerbela, Kerbela, Iraq
² Faculty of Science, Department of Biology, University of Kufa, Najaf, Iraq

^* Corresponding author: Ohood.S@uokerbala.edu.iq

Abstract

Levan is one of the most significant microbial exopolysaccharides, and has long been subject of interest of many researchers due to its versatile use, it has been made for high value medical applications. As an exopolysaccharide (EPS), its produced by a great variety of microorganisms and a small number of plant species. As a result, the current study was designed to produce of levan from local Bacillus subtilis isolates, purification and characterization of Levan by using HPLC technique and FTIR spectroscopy. A total 8 isolates of B. subtilis were obtained from Al-Amin center in Al-Najaf city, as a local levan producing isolates isolated from soil, which were detected by vitek2 system, hi this study: only 3 isolates were characterized by their high viscosity similar to the glue around their colonies on the medium of mineral salts agar modified by 20% sucrose within 48h of the incubation period. All isolates were subjected to secondary screening to select the most efficient and most productive of levan on mineral salts broth medium modified by sucrose 20%. Under optimum fermentation conditions, our results showed the local(B. subtilis-3)isolate was superior in the amount of levan produced reached (6.5g/L)using a modified MSB medium of 20% sucrose in 48h, an inoculum volume of 1×10⁸ cell/ml at 2% in 35°C, pH=7.0 and 150rpm, followed by(B. subtilis-1 and B. subtilis-2)isolates. were less productive of levan (5.3 and 4.2g/L)respectively. The levan produced from local isolate Bacillus subtilits was identified after extracting and purifying it to confirm it belongs using HPLC and FTIR.