Mixed-mode resins: taking shortcut in downstream processing of raw-starch digesting alpha-amylases

Bacillus licheniformis 9945a alpha-amylase is known as a potent enzyme for raw starch hydrolysis. In this paper, a mixed mode Nuvia cPrime (TM) resin is examined with the aim to improve the downstream processing of raw starch digesting amylases and exploit the hydrophobic patches on their surface. This resin combines hydrophobic interactions with cation exchange groups and as such the presence of salt facilitates hydrophobic interactions while the ion-exchange groups enable proper selectivity. alpha-Amylase was produced using an optimized fed-batch approach in a defined media and significant overexpression of 1.2 g L-1 was achieved. This single step procedure enables simultaneous concentration, pigment removal as well as purification of amylase with yields of 96% directly from the fermentation broth.