Hydrogen peroxide (H2O2) supply significantly improves xanthan gum production mediated by Xanthomonas campestris in vitro

To improve xanthan gum productivity, a strategy of adding hydrogen peroxide (H2O2) was studied. The method could intensify oxygen supply through degradation of H2O2 to oxygen (O-2). In shake flask testing, the xanthan gum yield reached 2.8% (improved by 39.4%) when adding 12.5 mM H2O2 after 24 h of fermentation. In fermentor testing, it was obvious that the oxygen conditions varied with the H2O2 addition time. Eventually, gum yield of 4.2% (w/w) was achieved (increased by 27.3%). Compared with the method of intense mixing and increasing the air flow rate, adding H2O2 to improve the dissolved oxygen concentration was more effective and much better. Moreover, addition of H2O2 improved the quality of xanthan gum; the pyruvate content of xanthan was 4.4% (w/w), higher than that of the control (3.2%).