Obtaining Cyclodextrins by Bacillus firmus strain 37

Abstract

The Ciclomaltodextrin-glucanotransferase (CGTase) is the only enzyme capable to convert starch into Ciclodextrins (CDs) by the cyclization of straight chains. Cyclodextrins are cyclic oligosaccharides containing a minimum of 6 units of D-(+)-glucopyranose linked by alpha-1,4. They are capable of forming inclusion complexes with a variety of guest molecules in solution. With the exploratory objective of increasing production of CGTase for obtain  Cyclodextrins it was held a cultivation of Bacillus firmus CEPA 37 in batch reactor with pulses of starch at 48, 96 and 200 hours of culture. It was observed maintaining pH 8.9 and 10, there was good substrate consumption and a good cell growth (approximately 8 g/L). The enzymatic activity of CGTase peaked at 0.11 U/ml after 59 and 200 hours of cultivation, and a specific activity compared with gamma-CD of 1.4 U/mg protein to 200 hours of cultivation. There was a quantity increasing of soluble proteins in the culture media after the pulse of starch, indicating that the microorganism searched sources of nitrogen since the source of carbon was supplemented but the nitrogen not. The pulses of starch also favored the cell growth.