Bone-Bound Glucoamylase as a Biocatalyst in Bench-Scale Production of Glucose Syrups from Liquefied Cassava Starch

Green construction of recyclable amino-tannic acid modified magnetic nanoparticles: Application for β-glucosidase immobilization

The β-glucosidase (BGL) enzyme in food industry is great interest due to its role in food conversion to produce functional food products. In this study, the BGL was covalently immobilized onto amino-tannic acid modified Fe₃O₄ magnetic nanoparticles (ATA-Fe₃O₄ MNPs) as biocompatible nanoplatform by modified poly-aldehyde pullulan (PAP) as a cross-linker to enhance the ability and strength of the nanoparticle connection to the enzyme. The properties of support were subsequently characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier transformed infrared (FTIR), X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The highest percentage of loading and immobilization yield was obtained with 0.1 mg enzyme/mL citrate buffer (pH 6, 1 M) enzyme solution, carrier solution of 10 mg ATA-Fe₃O₄/3 mL citrate buffer (pH 6, 1 M), and PAP solution of 20% total reaction system volume. Optimum pH and temperature were found for free (pH 5.0 and temperature 30 °C) and immobilized (pH 6.0 and temperature 40 °C) enzyme. The immobilized BGL maintains its activity to 83% after 10 cycles. Therefore, immobilization of BGL by this method is an efficient procedure to improve the properties of enzyme.

Potential applications of carbohydrases immobilization in the food industry

Carbohydrases find a wide application in industrial processes and products, mainly in the food industry. With these enzymes, it is possible to obtain different types of sugar syrups (viz. glucose, fructose and inverted sugar syrups), prebiotics (viz. galactooligossacharides and fructooligossacharides) and isomaltulose, which is an interesting sweetener substitute for sucrose to improve the sensory properties of juices and wines and to reduce lactose in milk. The most important carbohydrases to accomplish these goals are of microbial origin and include amylases (α-amylases and glucoamylases), invertases, inulinases, galactosidases, glucosidases, fructosyltransferases, pectinases and glucosyltransferases. Yet, for all these processes to be cost-effective for industrial application, a very efficient, simple and cheap immobilization technique is required. Immobilization techniques can involve adsorption, entrapment or covalent bonding of the enzyme into an insoluble support, or carrier-free methods, usually based on the formation of cross-linked enzyme aggregates (CLEAs). They include a broad variety of supports, such as magnetic materials, gums, gels, synthetic polymers and ionic resins. All these techniques present advantages and disadvantages and several parameters must be considered. In this work, the most recent and important studies on the immobilization of carbohydrases with potential application in the food industry are reviewed.