72-79The cyclodextrin glycosyltransferase
(CGTase) of Paenibacillus pabuli US132 was fused to the secretive lipase
signal peptide of B. subtilis. This leads to an efficient secretion of
the recombinant enzyme into the culture medium of E. coli as an active
and soluble form contrasting with the native construction leading to a
periplasmic production. In order to enhance the yield of CGTase production, an
experimental design methodology was applied for the optimization of the culture
composition. Hence, the media components were submitted to preliminary
screening using a Plakett-Burman design. The concentrations of the major
operating ones were then optimized to enhance the secretion of CGTase using
response surface methodology. The findings revealed that concentrations of 0.5%
potato starch, 3% yeast extract, 3% tryptone, 1.5% casein hydrolysate, 0.5%
NaCl, 0.2% KH2PO4, and 0.02% MgSO4 were the
optimal conditions for CGTase production. The experimental value (9.43 U/ml) obtained for CGTase activity was
very close to the predicted value (9.27 U/ml)