Optimization of Xanthan Gum Production by Xanthomonas Campestris Isolated from Cabbage Leaves Sold in Keffi, Nigeria

Xanthan is a water-soluble hetero-exopolysaccharide produced by the plant pathogenic bacterium Xanthomonas campestris. This investigation aimed at production from Xanthomonas campestris isolated from cabbage leaves sold in Keffi and Jos, Nigeria. Standard microbiological methods were employed for isolation and identification of the Xanthomonas campestris cabbage leaves. The yields of xanthan gum produced by the various isolates of the Xanthomonas campestris were determined using ethanol to precipitate the gum. The occurrence of of Xanthomonas campestris was 26.0 % and the isolation rate of from Keffi was 24.0 % and from Jos was 12.0 %. The screening xanthan gum showed that two species of the Xanthomonas campestris isolated was able to produce xanthan gum isolate with code Xjc2 produced 11.0 ± 0.03 g/l and Xkc5 produced 0.6 ± 0.00 g/l. On effect of pH the highest xanthan gum was produced by Xkc5 at pH 6.0 (1.09g/l) with biomass of (2.78g/l) and the lowest was at pH 4.0 (0.44g/l) and biomass (0.74g/l) While Xjc5 produced highest at pH 5.5 (1.12g/l) and biomass (3.78 g/l) and lowest was at pH 4.0 (0.34g/l) and biomass (0.78g/l). On effect of temperature the highest xanthan gum produced by Xkc5 was recorded at 30oC (1.11 g/l) and biomass (3.88 g/l) and the lowest was at 45 oC (0.37 g/l) and biomass (1.65g/l) while Xjc2 produced highest at 30oC (1.91 g/l) and biomass (4.97 g/l) 45 oC (0.41 g/l) and biomass (1.52g/l). The highest xanthan gum was produced by Xkc5 was observed at 80% concentration of (1.00g/l) and biomass of (4.04g/l) and the least was at 20% concentration (0.39g/l) and biomass (0.92g/l) while Xjc2 produced highest at 80% concentration (1.09g/l) and biomass of (3.89g/l) and the lowest was at 20% concentration (0.47g/l) and biomass of (1.22g/l). The highest xanthan gum was produced by Xkc2 was observed after 120 hours (1.38g/l) and biomass (3.38g/l) and the lowest was after 24 hours (0.35g/l) and biomass (0.98g/l) while Xjc2 produced highest after 144 hours (1.41g/l) and biomass (4.12 g/l) and lowest was after24 hours (0.24g/l) and biomass (1.20 g/l). The Xanthomonas campestris isolated from cabbage leaves sold in Keffi and Jos revealed great ability in production of xanthan gum.