Purification and characterization of a novel alkali-stable α-amylase from Chryseobacterium taeanense TKU001, and application in antioxidant and prebiotic

摘要

Chryseobacterium taeanenseTKU001 was isolated from soils using red-koji rice as the sole carbonitrogen sources. Mung bean is a widely used traditional oriental food material and has been reported as a healthy food. For further investigating the possibility of microbial reclamation of mung bean, TKU001 was tested for producing a-amylase using mung bean powder as the sole carbonitrogen source. Following fermentation, an a-amylase was purified from the culture supernatant. The a-amylase has a molecular mass of 46,000 and 47,000 estimated by SDS-PAGE and gel filtration, respectively. The optimum pH, optimum temperature, pH stability, and thermal stability of the a-amylase were 9,50 ℃, 6-11, and <60 ℃, respectively. The enzyme efficiently hydrolyzed soluble starch to yield glucose and maltose as the end products. Addition of 5 mM Ca~(2+) and 2% (v/v)Tween 40 into the medium could increase amylase activity by 3.52 and 3.27 fold, respectively. Besides, when 1.5% mung bean powder was used as the carbonitrogen source, the culture supernatant had strong antioxidant activity and could enhance the growth of Lactobacillus paracasei subsp. paracasei TKU010.