Synthesis of Cyclodextrin glycosyl transferase by immobilized cells of Bacillus circulans
Tóm tắt
The cells of Bacillus circulans (ATCC 21783) immobilized in sodium alginate gel matrix were able to synthesize the extracellular enzyme, Cyclodextrin glycosyl transferase (CGTase, E.C. 2.4.1.19) which is industrially employed for the preparation of cyclodextrins. Optimization for the maximum production of enzyme was carried out by varying the cell density (3.3–53.5 kg/m3) in the gel and the incubation temperature (30°–42°C). The CGTase activity was found to be the highest (45 units/cm3) with maximum cell loading at 37°C. The reusability of immobilized cells was ascertained by repeated batch experiments. The enzyme activity exhibited was in the range of 50 to 55 units/cm3 in each batch. The continuous synthesis of CGTase by immobilized cells has been demonstrated by operating a fluidized bed reactor at a dilution rate 1.1 · 10−4 sec−1 for a period of 15 days. The enzyme activity has decreased to 42.5 units/cm3 from an initial value of 61 units/cm3 during continuous operation.
Tài liệu tham khảo
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