Optimization of submerged culture conditions for exo-biopolymer production by Paecilomyces japonica

Abstract

Optimization of submerged culture conditions for the production of eso-biopolymer from Paecilomyces japonica was studied. Maltose, yeast extract, and potassium phosphate were the most suitable sources of carbon, nitrogen, and inorganic salt, respectively, for both production of the exo-biopolymer and mycelial growth. The optimal culture conditions in a flask culture were pH 5.0, 25 degrees C, and 150 rpm in a medium containing (as in g/l) 30 maltose, 6 yeast extract, 2 polypeptone, 0.5 K2HPO4, 0.2 KH2PO4, 0.2 MnSO4 . 5H(2)O, 0.2 MgSO4 . 7H(2)O. Exo-biopolymer production and mycelial growth in the above suggested medium were significantly increased in a 2.5-1 jar fermenter, where the maximum biopolymer concentration was 8 gn. The morphological changes of the mycelium in the submerged culture were observed within pH ranges from 4.0 to 9.0, i.e.. growth of the filamentous form was optimal at culture pHs of 5.0 and 6.0, whereas pellet was formed at other pHs.