Semi-continuous production of xanthan in biofilm reactor using Xanthomonas campestris

Semi-continuous production of xanthan gum using self-immobilized Xanthomonas campestris cells in biofilm reactors was studied. Fermentation carried out two different designs reactor equipped with a) stainless-steel support (SSS) and b) polyethylene (PES). performed three cycles refreshing the media at beginning each: cycle 1, 0−27 h; 2, 27−54 3, 54–78.5 h. Results showed that glucose consumption pH reduction PES faster compared to SSS reactor. Scanning electron microscopy capable immobilize more during growth X. campestris. The maximum concentration obtained after 27 h (3.47 ± 0.71 g/L), while 78.5 (3.21 0.68 g/L). Thermal stability analysis differential scanning calorimetry presence fractures attributed dehydration degradation polymer. thermogram represented both endothermal exothermal behaviour Furthermore, functional groups molecular structure produced this study evaluated Fourier transform infrared spectrometry also proton nuclear magnetic resonance. addition, surface tension (0.2 %, w/v) solution a range 52.16–56.5 mN/m. Rheological G′ values were higher than G″ all frequencies demonstrating relatively high elasticity gum.