Plant β-Galactosidases: Physiological Significance and Recent Advances in Technological Applications

The β-galactosidase (BGAL) is one of the oldest ubiquitous enzymes, known for more than 100 years. The enzyme is known to perform various functions in different organisms, however with similar mode of action. There is an immense literature available related to bacterial, fungal as well as animal BGAL compared to plant BGAL. Initially, it was believed that lactose is the only substrate for the enzyme. Later, it was observed that enzyme specificity is due to hydrolysable bond rather than the substrate. The present review is based on the role of BGAL in plants, the in vivo substrates and their physiological significances. Similarity as well as dissimilarity with BGAL from bacterial as well as fungal sources is also discussed. Plant BGAL would be best suited for industrial applications because of its easy availability, cost effectiveness and easy adaptability.