Isolation of Xanthomonas campestris pv. campestris from seed and soil samples and investigation of their xanthan gum production avability

11 ABSTRACT Master of Science Thesis ISOLATION OF XANTHOMONAS CAMPESTRÎS PV.CAMPESTRIS FROM SEED AND SOIL SAMPLES AND INVESTIGATION OF THEIR XANTHAN GUM PRODUCTION AVABİLİTY MERAL YILMAZ Anadolu University Graduate School of Natural and Applied Sciences Biology Program Supervision Assoc. Prof. Kıymet GÜVEN 2002, 80 pages Xanthan gum is a complex exopolysaccharide produced by the plant- pathogenic bacterium Xanthomonas campestris pv. campestris. Xanthan gum is widely used as a suspending, stabilizing or thickening agent in the food industry. It is also used as a lubricant, emulsifier agent in the oil-drilling industry. Therefore, production of this polysaccharide is very important. In this study, first of all Xanthomonas campestris from different seeds and soil samples tried to be isolated. Later the study was focused to following goals: the production of Xanthan gum by using different substrate to determine which substrate is best to produce highest Xanthan gum with following Xanthomonas strains (standart strain Xanthomonas campestris pv. campestris NRRL B-1459, isolate Xanthomonas campestris pv. phaseoli TPPB 5001 from Turkish bean plant, isolate Xanthomonas campestris pv. vesicotoria from Turkish tomato plant and isolate Xanthomonas axonopodis pv. vesicotoria from American stuffing pepper). The results of these studies suggest that sickened crucifer plant seeds and soil samples of this plants are possibly best to isolate Xanthomonas campestris. These studies also suggest that Triton X-100 added beet sugar molasses could be an alternative substrate for the production of Xanthan gum compared to substrates used such as glucose and sucrose. Keywords: Xanthan gum, Exopolysaccharides, Xanthomonas campestris