Statistical Optimization of Alkaline Levan Production using Bacillus subtilis

The industrially used biopolymer levan as an emulsifying agent was produced in large amounts by optimizing the physical parameters like pH, temperature and incubation time, with the central composite design under the response surface methodology where the maximum yield of levan was found to be 268 μg/ml at a pH of 8.0, a temperature of 20°C and the incubation period of 24^th h. The pH- and thermal stabilities of levan-forming activity were studied and arrived at the maximum activity at pH 7.0 and at 20°C respectively, thereby inferring that the levan is optimally produced by Bacillus subtilis in an alkaline environment. Scanning electron microscope was used to examine the surface morphology levan-producing Bacillus subtilis that showed the levan polymer as white dust-like particles.