Improved production of natural food preservative ε-poly-l-lysine using a novel producer Bacillus cereus

An indigenously isolated Bacillus cereus isolated from soil was found to be capable of producing ε-poly-l-lysine (ε-PL), a homo-poly-amino acid of l-lysine which is used as a safe food preservative. The production of the ε-PL was optimized by identifying the most significant components of the medium which affect its production under shake-flask conditions. One factor at a time method was studied for investigation of media components while orthogonal array method was used to determine the optimum composition of various components. The ε-PL yield increased significantly from 36.29 mg/l in basal medium to 83.49 mg/l in the optimized medium containing 5% glucose, 1% yeast extract, 1.5% ammonium sulphate, 0.05% magnesium sulphate and 0.004% zinc sulphate. Thus more than two-fold increase in ε-PL production was achieved using a novel producer, which by further modifications can be exploited as a potential commercial strain.