Production of xanthan gum from soybean biodiesel: a preliminary study

Background Xanthan gum, a commercial microbial polysaccharide, has many industrial applications, including the tertiary recovery of oil, due to its unique rheological behavior (e. g. high viscosity at low concentrations, pseudoplasticity, solubility, stability over a wide range of pH values and temperatures, compatibility with many salts) [1]. Its production employs glucose or sucrose, which raises the price of xanthan production. One way to reduce the cost is to use cheaper alternative substrates, like residues [2]. Biodiesel is included in this context because its chemical composition is susceptible to oxidation, which decreases its capacity as a fuel, resulting in the possibility of organic residue accumulation [3]. Thus, biodiesel conversion into xanthan gum by a fermentation process is one alternative for reducing costs, since the substrate is a critical aspect in its commercial production, and also for minimizing possible environmental impacts. Accordingly, the goal this study was to evaluate the effect of soybean biodiesel as an alternative substrate for non-food grade xanthan gum biosynthesis.