Immobilization of Thermostable Maltogenic Amylase from Bacillus stearothermophilus for Continuous Production of Branched Oligosaccharides

A new thermostable maltogenic amylase isolated from Bacillus stearothermophilus (BSMA) was immobilized and characterized for continuous production of branched oligosaccharides (BOS). Immobilized BSMA had characteristics similar to those of the free form, except its stability with respect to temperature and metal ions was improved. The optimum condition for continuous production of BOS using a packed bed column reactor of immobilized BSMA was a flow rate of 11 mL/h and a 20% substrate concentration. As the flow rate or concentration of the substrate increased, generally, the content of sugars having a higher molecular weight were increased and vice versa, suggesting the possibility of controlling the composition of BOS by adjusting the above two factors. The yield of BOS was maintained at 50% up to 20 days and gradually decreased to 40% over 37 days of continuous process. About 93% high-purity BOS was obtained by removing glucose and maltose by yeast fermentation. Keywords: Branched oligosaccharides; maltogenic amylase; Bacillus stearothermophilus; immobilization; continuous production