Production of levan by Bacillus licheniformis NS032 in sugar beet molasses-based medium

The production of levan by Bacillus licheniformis NS032 in a medium based on sugar beet molasses was studied. High polysaccharide yields were produced by using diluted molasses (100–140 g/L of total sugars) with the addition of commercial sucrose up to 200 g/L of total sugars, as well as K2HPO4. A levan yield of 53.2 g/L was obtained on a medium optimized by response surface methodology, containing 62.6% of sugar originating from molasses, and 4.66 g/L of phosphate, with initial pH value of 7.2. In comparison to the media with 200 and 400 g/L sucrose, in the molasses optimized medium, the observed bacterial growth was faster, while the maximum production of polysaccharide was achieved over a shorter time interval (48 h). The polysaccharide produced in molasses medium had a weight average molecular weight of 5.82 × 106 Da, degree of branching 12.68%, viscosity of 0.24 dL/g, and based on methylation analysis and NMR data, it did not significantly differ from levan obtained in the medium with 200 g/L sucrose. © 2018 Elsevier B.V. Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/2943] This is peer reviewed version of the following article: Gojgic-Cvijovic, G. D.; Jakovljevic, D. M.; Loncarevic, B. D.; Todorovic, N. M.; Pergal, M. V.; Ciric, J.; Loos, K.; Beškoski, V.; Vrvić, M. M. Production of Levan by Bacillus Licheniformis NS032 in Sugar Beet Molasses-Based Medium. International Journal of Biological Macromolecules 2019, 121, 142–151. [https://doi.org/10.1016/j.ijbiomac.2018.10.019]