Optimization of exopolysaccharide welan gum production by Alcaligenes sp. CGMCC2428 with Tween-40 using response surface methodology

► The effect of additives on exopolysaccharide welan gum was studied. ► Tween-40 was proved to be the best additive. ► Response surface methodology was employed to optimize the culture conditions. ► The maximum welan gum concentration (24.90 ± 0.68 g/l) was obtained.