Production of gellan gum by Sphingomonas paucimobilis NK2000 with soybean pomace

The ammonium nitrate as a nitrogen source for the production of gellan gum by Sphingomonas paucimobilis NK2000 enhanced the cell growth but its depletion was essential for higher production of gellan gum. The highest production of gellan gum was 3.27 g l −1 when the concentrations of glucose and bacto-peptone were 2.0% (w/v) and 0.05% (w/v). The production of gellan gum by S. paucimobilis NK2000 increased with increased concentration of soybean pomace substituted for bacto-peptone up to 2.0% (w/v). The highest production of gellan gum was 7.33 g l −1 in a flask scale when the concentrations of glucose and soybean pomace without ammonium nitrate were 2.0% and 2.0% (w/v). The highest production of gellan gum with the same concentrations of glucose and soybean pomace was 7.50 g l −1 in a 7 l bioreactor whereas that with 2.0% (w/v) glucose and 0.05% (w/v) bacto-peptone was 4.95 g l −1.