Optimization of some cultural factor of native strain of Xanthomonas campestris b82 with Taguchi method for production of microbial xanthan gum

Xanthan is one of the most important industrial biopolymer which is produced by different strains of genus of Xanthomonas. In this study we use Taguchi experimental design for optimization of magnesium، iron، sulfur، nitrogen and phosphorus sources in culture medium of native xanthan producer strain b82 of Xanthomonas campestris which recently has been screened and identified. Our results showed that in optimal condition (phosphate source content with optimal concentration of 5. 8 g/l kalium phosphate، magnesium source content with optimal concentration of 0. 24 g/l magnesium sulfate، sulfur source content with optimal concentration of 2. 8 g/l sodium sulfate، nitrogen source content with optimal concentration of 1. 2 g/l ammonium chloride، iron source content with optimal concentration of 1. 68mg/l ferric chloride) xanthan production was 16. 11-21. 45 g/l with Confidence degree 95%. In addition، we showed that concentration of magnesium source is key factor of xanthan production، although nitrogen source is more important for bacterial growth and iron source is the most efficient factor of viscosity production.