Induction studies of a novel α-glucosidase purified from Lactobacillus fermentum grown on resistant starch

Abstract

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. Abbreviation used: RS: Resistant starch.