Improvement of functional properties of a thermostable β-glycosidase for milk lactose hydrolysis

Recent Advances and Perspectives on Food-Grade Immobilisation Systems for Enzymes

The use of enzyme immobilisation is becoming increasingly popular in beverage processing, as this method offers significant advantages, such as enhanced enzyme performance and expanded applications, while allowing for easy process termination via simple filtration. This literature review analysed approximately 120 articles, published on the Web of Science between 2000 and 2023, focused on enzyme immobilisation systems for beverage processing applications. The impact of immobilisation on enzymatic activity, including the effects on the chemical and kinetic properties, recyclability, and feasibility in continuous processes, was evaluated. Applications of these systems to beverage production, such as wine, beer, fruit juices, milk, and plant-based beverages, were examined. The immobilisation process effectively enhanced the pH and thermal stability but caused negative impacts on the kinetic properties by reducing the maximum velocity and Michaelis-Menten constant. However, it allowed for multiple reuses and facilitated continuous flow processes. The encapsulation also allowed for easy process control by simplifying the removal of the enzymes from the beverages via simple filtration, negating the need for expensive heat treatments, which could result in product quality losses.

Challenges and perspectives of the β-galactosidase enzyme

The enzyme β-galactosidase has great potential for application in the food and pharmaceutical industries due to its ability to perform the hydrolysis of lactose, a disaccharide present in milk and in dairy by-products. It can be used in free form, in batch processes, or in immobilized form, which allows continuous operation and provides greater enzymatic stability. The choice of method and support for enzyme immobilization is essential, as the performance of the biocatalyst is strongly influenced by the properties of the material used and by the interaction mechanisms between support and enzyme. Therefore, this review showed the main enzyme immobilization techniques, and the most used supports for the constitution of biocatalysts. Also, materials with the potential for immobilization of β-galactosidases and the importance of their biotechnological application are presented. KEY POINTS: • The main methods of immobilization are physical adsorption, covalent bonding, and crosslinking. • The structural conditions of the supports are determining factors in the performance of the biocatalysts. • Enzymatic hydrolysis plays an important role in the biotechnology industry.

Forty years of study on the thermostable β-glycosidase from S. solfataricus: Production, biochemical characterization and biotechnological applications

The aim of this paper is to make the point on the fortieth years study on the β-glycosidase from Sulfolobus solfataricus. This enzyme represents one of the thermophilic biocatalysts, which is more extensively studied as witnessed by the numerous literature reports available since 1980. Comprehensive biochemical studies highlighted its broad substrate specificity for β-d-galacto-, gluco-, and fuco-sides and also showed its remarkable exo-glucosidase and transglycosidase activities. The enzyme demonstrated to be active and stable over a wide range of temperature and pHs, withstanding to several drastic conditions comprising solvents and detergents. Over the years, a great deal of studies were focused on its homotetrameric tridimensional structure, elucidating several structural features involved in the enzyme stability, such as ion pairs and post-translational modifications. Several β-glycosidase mutants were produced in the years in order to understand its peculiar behavior in extreme conditions and/or to improve its functional properties. The β-glycosidase overproduction was also afforded reporting numerous studies dealing with its production in the mesophilic host Escherichia coli, Saccharomyces cerevisiae, Pichia pastoris, and Lactococcus lactis. Relevant applications in food, beverages, bioenergy, pharmaceuticals, and nutraceutical fields of this enzyme, both in free and immobilized forms, highlighted its biotechnological relevance.