Studies on Biotechnological Potential of Xanthomonas Species

Abstract

Xanthomonas axonopodis pv. citri is well known as they cause important plant diseases specifically named as citrus canker. The strains of Xanthomonas axonopodis pv. citri produce various types of pectinolytic enzymes Polygalacturonases (PG), Polymethyl galacturonases (PMG), Pectin lyases (PnL) and Pectate lyases (PgL) as well as extracellular polysaccharides in the form of xanthan gum during infection of plants. Species of viz. Xanthomonas axonopodis pv. citri and Xanthomonas campestris pv. campestris synthesizes cell wall degrading enzymes. Pectinases are extensively used in fruit juice processing (extraction and clarification), vegetable oil extraction, processing of alcoholic beverages and a variety of applications in food industries. Xanthan gum is used in food industries, the gum exhibits many advantages as a thickener, stabilizer, gelling agent and suspending agent, as creams, artificial juices, sauces for salads, meat, chicken or fish, as well as for syrups and coverings for ice creams and desserts as it has high degree of stability and solubility. Owing to the potential and wide applications of pectinases and xanthan gum, it was thought proper to study various aspects affecting their production. Considering all these physiological aspects of the Xanthomonas species, this study was undertaken with the following objectives: newline1. Isolation of Xanthomonas sps. from plant and soil. newline2. Screening of Xanthomonas sps. for production of cell wall degrading enzymes and newlinexanthan gum. newline3. Standardization and optimization of process for the production of cell wall degrading newlineenzymes and xanthan gum. newlinevi newlineFor this study, infected samples of citrus plants were collected from Marathwada region as Nanded, Aurangabad, Parbhani and Latur from 2009 to 2011. Total fifty strains of Xanthomonas axonopodis pv. citri were isolated from these infected samples. Among all fifty strains screened in this study, four strains were used for optimization study as they were efficient strains and these were as Xan 4, Xan 13, Xan 28 and Xan 43. The