Isolation and Characterization of Levan from Moderate Halophilic Bacteria Bacillus licheniformis BK AG21

Levan is fructose polymer as the result of biosynthesis by levansucrase. This study is aimed to explore the potential of moderate halophilic bacteria Bacillus licheniformis BK AG21 isolated from Bledug Kuwu, Purwodadi Central Java, in producing levan. This bacteria displayed positive potential in producing levan based on the appearance of slime mucoid on a sucrose medium. The optimum production of levan was attained when the culture medium containing sucrose and peptone as respective carbon and nitrogen sources was shaking incubated with speed of 150 rpm for 24 hours at 37 ^oC. Thermal gravimetric analysis revealed that levan produced by B. licheniformis BK AG21 decomposed at 214 ^oC. The structure of the isolated levan was elucidated with FTIR, ¹H and ¹³C NMR spectroscopies. Based on the obtained spectroscopic data, the isolated levan was composed of β-(2,6)-linkages of fructose residues.