Xanthan from sulphuric acid treated tapioca pulp: Influence of acid concentration on xanthan fermentation

•Xanthan produced from tapioca pulp.•Acid concentration influenced the hydrolysis and hence fermentation.•0.5% Sulphuric acid yield maximum xanthan production.•Xanthan produced had molecular weight 1.68×106g/mol and intrinsic viscosity 2.13×103ml/g. Xanthan gum was produced by fermentation of sulphuric acid pre-treated tapioca pulp. Effect of sulphuric acid concentration (0.5%, 2.5% and 5.0%) on xanthan fermentation was investigated. Maximum xanthan yield (7.1g/l) was obtained with 0.5% sulphuric acid pre-treatment. Further, increase in sulphuric acid concentration caused formation of inhibitory substance and lowered xanthan yield. The product was confirmed as xanthan using FTIR, 1H NMR analyses. Viscosity was measured by Brookfield viscometer and the molecular weight was determined from the intrinsic viscosity. The results confirmed that the yield and quality of xanthan produced were strongly influenced by the acid concentration.