Screening of Endophytic Fungi for Xanthine Oxidase Producer (S)

Abstract

Increasing concern for xanthine oxidase related disorders, like gout, hyperuricemia, aging, myocardial infarction, reperfusion injury and many others has made xanthine oxidase, one of the largest diagnostic enzyme in demand, in clinical industry. Moreover, XO has been used in various other applications, such as, development of miniaturized amperometric biosensors for monitoring substrate utilization in cell culture media and is required to explore answers to a number of questions like what all defects in the gene lead to various XO related disorders and to throw a light on the metabolic pathways of oxidoreductase class of enzymes. Investigators have been searching novel xanthine oxidase sources, with high level of production capacity, so that this high demand of XO in the market can be met efficiently. In the current study, we explored a new group of microorganisms, the endophytic fungi, for the production of xanthine oxidase. The potential of endophytic fungi to degrade/utilize xanthine was assessed by growing fungi on a solid medium containing xanthine as a sole carbon and nitrogen source. Isolates those were capable of growing on such medium showed high filamentous growth indicating utilization of xanthine. Such isolates were then raised in production medium (Xanthine Broth supplemented with 2 mmoles/L xanthine). #4CMBANEY, #21CMBANEY and #12RSBANEY showed acceptable enzyme activity while #19NOBASVNP demonstrated maximum potential. #19NOBASVNP is an endophytic fungus isolated from Nerium oleander, an ornamental plant. Enzyme activity in crude protein precipitate obtained from cell free filtrate of this isolate was assessed by an enzyme assay, designed on the basis of the method described by Agarwal and Banerjee, and the enzyme activity staining. Further studies on protein purification, characterization, kinetics would open up possibilities of protein engineering for commercial exploitation of this enzyme.