Immobilization of Cryptococcus flavus α‐amylase on glass tubes and its application in starch hydrolysis

α‐Amylase from Cryptococcus flavus was previously purified after exchange chromatography on Q‐Sepharose and gel filtration on Sephacryl S‐100. The enzyme was purified 128‐fold with a recovery rate of 81% of activity. The molecular mass of the α‐amylase was 67 kDa as determined by SDS–PAGE. The enzyme was characterized after immobilization on glass tubes. The immobilization yield, efficiency, and activity recovery of α‐amylase were 79, 57, and 45%, respectively. The optimum pH of the immobilized enzyme was shifted to a more acidic pH (4.5) compared with the free enzyme (5.5). The optimum temperature of the immobilized enzyme was the same for the free enzyme (50°C), but it showed a higher thermal stability. The immobilized enzyme showed activity until the 10th cycle, maintaining 47% of initial activity, and was capable of hydrolyzing starch from potato, wheat, corn, and cassava. The main products released from starch were maltose, maltotriose, and maltotetraose.