2.3. Recovery of biopolymer
After fermentation, 6 volumes of cold distilled water were added to the fermentation sample and uniformly mixed in an orbital shaker for 2 h at 200 rpm [20]. Subsequently, the mixture was centrifuged at 10,000 rpm for 15 min at 4◦C. Solid material with cell debris was carefully gathered and dried in a hot air oven at 90◦C. One volume of supernatant was blended with two volumes of ethanol at 4◦C for 24 h for precipitation. Then precipitated sample was resuspended and centrifuged at 10,000 rpm and 4◦C for15 min to recover the product. Precipitated sample was dried in hot air oven at 90◦C [23]. The yield of pullulan was expressed in mg of pullulan/g of dry substrate (mg/gds).