Effect of PH and Metal Ions on Α-Amylase, Produced from Probiotic Lactic Acid Bacteria

Abstract

Amylases are starch degrading enzymes which can be obtained from different sources such as plants, animals and microorganisms. Among microbial sources bacteria and fungi are mostly used for the production of α-amylase both at small and industrial scale. Lactic acid bacteria are the preferred for the production of α-amylase because the microbial strain can be used as probiotics that possess antimicrobial activity by producing antimicrobial substances such as bacteriocin and also are the producers of industrially important enzymes such as amylases, and can also be used for the preservation of fermented food. The four probiotic bacterial strains isolated from milk samples were screened for amylolytic activity and two strains MM1 and GD were producing comparatively more amylase qualitatively with clearance zone of 5mm and 6mm respectively. The enzyme produced by both MM1 and GD strains showed maximum catalytic activity at pH 5. Metal ions such as Na2SO4, MgSO4, CuSO4, also enhanced the amylolytic activity. Both MM1 and GD bacterial strains produced maximum amylase units when refined starch was used as a substrate. Amylase found potential applications in food, feed, textile, detergent, paper, pulp, textile and biofuels industries.