Induction Studies of a Novel α‑Glucosidase Purified from Lactobacillus fermentum Grown on Resistant Starch

Aim: The aim of this study is to investigate the induction studies of resistant starch (RS)‑degrading enzyme purified from Lactobacillus fermentum. Background: RS is one of the components of dietary fiber and considered as a good prebiotic. Earlier studies from our laboratory reporting L. fermentum to be the most efficient in degrading RS among several lactic acid bacteria tested. L. fermentum produced α‑glucosidase when grown on RS, which was purified biochemically and characterized. Results and Discussion: The alpha‑glucosidase was synthesized de novo and was repressed by glucose. Known protein synthesis inhibitors such as potassium cyanide, 2,4‑dinitrophenol, and tetracycline were found to inhibit α‑glucosidase synthesis. Cyclic adenosine 3’,5’‑monophosphate was found to be a stimulator of α‑glucosidase synthesis; however, it did not have any impact on the lag phase. Glutamate acted as an excellent nonrepressing carbon source. Maltooligosaccharides, dextrins, and soluble starch had varied influence on the induction of α‑glucosidase synthesis. Conclusion: In the present communication, possible factors regulating α‑glucosidase synthesis in L. fermentum were examined and discussed in terms of catabolite and apparent temperature‑sensitive repression, culture age, induction, inhibitors, and various carbon sources.