Biotechnological potential of microbial α-galactosidases

The enzyme α-galactosidase (α-D-galactoside galactohydrolase; EC 3.2.1.22) catalyzes the hydrolysis of α-1,6-linked galactose residues in oligosaccharides and polymeric galactomannan. The α-galactosidases are of particular interest in view of their many potential biotechnological and medical applications. These enzymes have found wide use in various industries such as food and feed, sugar and paper and pulp for the removal of raffinose and stachyose. They are also important medically for blood group conversion and in the treatment of Fabry disease. Most of the research on α-galactosidases has focused on their isolation from various microbial sources. In the last decade, cloning of novel α-galactosidase genes and their heterologous expression has gained momentum. The present review focuses on the production of α-galactosidases from bacteria, fungi and yeast, and discusses their properties. Recent progress on cloning and heterologous expression in various hosts is summarized with special emphasis on their application in various fields.