Production of Pullulan From Beet Molasses and Synthetic Medium by Aureobasidium pullulans

Authors : Yekta GÖKSUNGUR, Aslı UÇAN, Ulgar GÜVENÇ

Pages : 23-30

View : 13 | Download : 6

Publication Date : 2004-12-01

Article Type : Research Paper

Abstract :The production of pullulan from molasses and synthetic medium by Aureobasidium pullulans P56 in batch culture was investigated. Among the pretreatments of molasses used to increase polysaccharide production, sulfuric acid + activated carbon treatment gave better results with regard to polysaccharide concentration, polysaccharide yield and sugar utilization. A maximum polysaccharide concentration of 21.4 g l-1 and a pullulan concentration of 16.7 g l-1 were obtained in synthetic medium whereas 35.0 g l-1 of polysaccharide and 16.9 g l-1 of pullulan were obtained in molasses medium containing 50 g l-1 of initial sugar at pH 7.5. The highest pullulan contents of the crude polysaccharide were 85.3 and 48.3% for synthetic medium and molasses medium, respectively and this showed that A. pullulans produced a mixture of pullulan and other polysaccharides in molasses medium. The experiments performed with synthetic medium showed that higher initial sugar concentrations led to a significant decrease in pullulan yield. A polysaccharide concentration of 20.4 g l-1 and a pullulan concentration of 6.6 g l-1 were obtained in a stirred tank bioreactor with synthetic medium. These concentrations were lower than those in shake flask culture.
Keywords : pullulan, beet molasses, synthetic medium, Aureobasidium pullulans