Production of α-amylase by solid phase fermentation and investigation of antidiabetic activities of some fungal extracts by α-amylase inhibition

In this study, thermotolerant VO3 strain isolated from mud samples taken from Bitlis Budaklı Thermal Springs was used as biological material. Morphological and biochemical tests and 16s rRNA gene sequence analysis revealed that the isolate belonged to the genus Bacillus and was closely related to Bacillus pumilus. It was aimed to produce α-amylase by using various agricultural wastes (cotton straw, lentil husk, rice husk, corn cob and millet husk) from the isolate by solid phase fermentation (KFF) method. The effects of different parameters such as incubation time, temperature, pH, inoculum ratio, moisture content, carbon and nitrogen sources were investigated. It was determined that the suitable substrate in KFF for the production of α-amylase from Bacillus pumilus was rice husk. In addition, it was determined that the optimum incubation time was 48 hours, the incubation temperature was 45°C and the initial pH was 7.0. It was found that enzyme production increased when starch was added as a carbon source and tryptone was added as a nitrogen source to the solid phase fermentation medium. In order to determine the antidiabetic effect of mushroom extracts, inhibition of amylase enzyme produced in this study was tested by using hexane, methanol and water extracts obtained from Coprinellus micaceus, Morchella tomentosa and Helvella queleti. The highest inhibitory activity was seen in methanol extracts of all three fungi. In α-Amylase inhibition experiments, 37.35%, 33.51% and 28.43% inhibition activities were determined in C. micaceus, M. tomentosa and H. queletii from methanol extracts, respectively.