Synergistic action of cyclodextrin glucanotransferase and maltogenic amylase improves the bioconversion of starch to malto-oligosaccharides

Abstract

Overwhelming consumer consciousness for healthier food has led to high market demand for functional oligosaccharides. These functional sugars can be extracted from various sources, especially starch, through enzymatic approaches. Maltogenic amylases are able to synthesise malto-oligosaccharides (MOS) from starch. However, the use of maltogenic amylase alone presents several limitations such as low specificity towards starch and low productivity of MOS. Cyclodextrin glucanotransferase (CGTase) acts on starch to produce cyclodextrins. Herein, asynchronous and synchronous conversion strategies were used to enhance the MOS yield from soluble starch by exploiting maltogenic amylase and CGTase reactions. Factors including pH, temperature, enzyme loading and enzymes ratio that affect MOS production were investigated. The combination of CGTase and maltogenic amylase (MAG1) from Bacillus lehensis G1 produced the highest MOS yield (307.9 mg.g−1). The synchronous strategy exhibited a 2.1-fold higher MOS production compared to the asynchronous approach (146.8 mg.g−1). Kinetic studies revealed that the catalytic efficiency of the synchronous approach was ∼800-fold (1746.1 mL.g−1. h−1) higher than that of MAG1 alone (18.5 mL.g−1. h−1). The high production of MOS and catalytic efficiency of the reaction demonstrate that the combinatorial catalysis of MAG1 and CGTase is very promising and provides a foundation for industrial-scale production of MOS.