ACTA Pharmaceutica Sciencia 2008 , Vol 50 , Num 3
BIOSYNTHESIS OF LEVANSUCRASE BY FREE AND IMMOBILIZED CELLS OF BACILLUS CIRCULANS INCLUDING CONTINUOUS FERMENTATION
AHMED F ABDEL-FATTAH, HEBA A EL-REFAI, FATEN A MOSTAFA
Chemistry of Natural and Microbial Products Dept.,National Reaserch Center, Dokki, Cairo, Egypt The optimal conditions for the production of the levansucrase by free and immobilized cells of Bacillus circulans were investigated including culture methodology and immobilization conditions with respects to matrix concentration, maximal cell loading and treatment with glutaraldhyde. In batch operation, the activity of the immobilized cells was extended for five repeated cycles, wherein, the activity remained between 15.08-8.66U/ml. Continuous production of levansucrase by immobilized cells of B. circulans was also investigated in packed bed bioreactor. Relatively high enzyme activity (14.12 U/ml) together with optimum specific productivity (7.3 U/g wet cells) was attained at dilution rate of 0.4 l/h. Our results revealed the feasibility of the immobilized cell technique. Keywords : LEVANSUCRASE, BACILLUS CIRCULAN, IMMOBILIZATION, CONTINUOUS FERMENTATION, LEVAN

Istanbul Medipol University