Peroxidases and Other Enzymes from Red Beet Hairy Roots

Enzymes are natural biocatalysts that initiate and accelerate a large ­number of biochemical reactions in living cells. The fact that an isolated enzyme could also accomplish specific reactions outside the cell has resulted in an enormous demand for industrial-scale production of different enzymes from microbes and cultured plant cells/organs. The soluble protein of Beta vulgaris was observed to display high activities of several enzymes of commercial importance, of which, type III peroxidases (POD) (EC 1.11.1.7), are interesting. These PODs are encoded by multigenic families in land plants, where they are involved in several important physiological, developmental and ecological processes. Because of their versatile functionalities, a wide range of chemicals can be modified by dual catalytic activity of POD (oxidoreductase) and, therefore, are useful for several novel applications. Presently, horseradish is sourced for high-quality POD for biochemical/clinical applications, whereas certain agricultural wastes/by-products have been suggested for commercial applications, although with limitations associated with difficulties in their purification. Alternatively, cultured plant cells and hairy roots have recently attracted profound attention. Cultured red beet hairy roots (RBHR) exhibit massive activities of PODs with some isomers released directly into the medium. The characteristics of RBHR POD were found comparable with those of horseradish peroxidase (HRP), and hence can be similarly used in reagents for clinical diagnosis, for tracking various ­biochemical events in laboratory experiments and for pollution monitoring. This chapter provides an overview of recent advances made in the identification and characterization of different enzymes, particularly POD and their commercial applicability. Other presumed/hypothetical applications and research trends in this direction are also discussed.