Studies on alkalophilic CGTase-producing bacteria and effect of starch on cyclodextrin-glycosyltransferase activity

摘要

The production of beta- and gamma-CD by CGTase from Bacillus firmus was studied, in regard to the effect of the source and concentration of starch on the yield of CD and CGTase activity. A cyclic activity of accumulation and consumption of beta-CD and gamma-CD occurred during the bacterial growth. CGTase was more active when citrate buffer, pH 5.5 was used. No differences were found for production of gamma-CD with the use of commercial starch flour when compared with corn starch (p>0.05). The use of commercial starch flour resulted in decreased conversion of starch to beta-CD (all the 4 starch sources were statistically different, p<0.05). The best results for beta-CD production were obtained with the use of corn starch. The specific activity of CGTase was not affected by starch concentration, different source of starch nor by the presence of glutamic acid, a CD-complexing agent.