Screening of polysaccharides for preparation of α-amylase conjugate to enhance stability and storage life

Nine polysaccharides differing in structure and chemical nature were screened for their ability to conjugate with α-amylase by covalent binding for enhancing the thermal and pH stability of α-amylase. Among these polysaccharides, agar, dextran, pectin and xanthan showed better results but dextran stood out among all the polysaccharide for providing both thermal and pH stability to α-amylase. α-Amylase conjugated with agar, dextran, pectin and xanthan showed antimicrobial property with added preservative (0.2% sodium benzoate) in liquid formulation of α-amylase challenged with Bacillus subtilis and Escherichia coli. Dextran was the only polysaccharide which showed significant reduction of microbial growth of challenged organisms and aerobic flora without any preservative added. Aerobic flora could flourish well in the liquid α-amylase, but low temperature (4 °C), dextran, and preservative showed synergistic effect in efficiently increasing the storage life of liquid α-amylase.