CYCLODEXTRINS ARE LIKELY TO INDUCE CYCLODEXTRIN GLYCOSYLTRANSFERASE PRODUCTION IN BACILLUS-MACERANS

Cyclodextrin glycosyltransferase (CGTase) activity was monitored in Ba cillus macerans culture fluids up to 56 h incubation time using glucos e (G(1)), maltose (G(2)), maltotriose (G(3)), maltoheptaose (G(7)), al pha-, beta-, gamma-cyclodextrins (CDs) and soluble starch as carbon so urces. Highest maximum specific growth rates (mu(max)) were observed w ith glucose, gamma-CD and soluble starch (mu(max) values were 0.86, 0. 74 and 0.69/h, respectively) while the maximum viable cell numbers wer e always within the range of 2.3-7.1 x 10(11) CFU/mL independently of the carbon source used. Highest CGTase production was found in the pre sence of soluble starch and G(7) (55.0 and 35.4 nkat/mL, respectively) , these saccharides being easily transformed to CDs by CGTase. Moreove r, when culture media were supplemented with cyclic maltooligosacchari des the CGTase activities were about twice higher (19.6-20.6 nkat/mL) than those obtained with the linear G(2) and G(3) saccharides (8.9 and 11.3 nkat/mL, respectively) which give rise only to negligible quanti ties of CDs. CDs, which are the major end products of the action of CG Tase, are regarded thus as the likely physiological inducers of the en zyme.