Study on the Conditions for Shaking Flask Fermentation of the Exopolysaccharide Production from An Oligotrophic Bacteria

Abstract:

An oligotrophic bacteria was isolated from oligotrophic environment(Gurbantunggut desert)in Xinjiang.This paper had ascer- tained the relationship between the main factors such as strain growth,nutrition demand,and the yield and viscosity of extracellular polysae- charide(EPS)by carrying on the experiment of single factor optimized culture medium(C-source.inorganic salts,etc.);the experiment of optimized conditions for shaking culture(temperature,time,the initial pH,dissolve oxygen).The optimum conditions for exopolysaccha-ride production were as follows: using sucrose as the carbon source,CaCO₃2g/L,initial pH of 7, seed age of 72-84h,KH₂PO₄0.3g/L,MgSO₄0.1g/L,inoculation quantity of 15%,cultivation 72h at 37℃,and 50 mL medium in a 250 mL flask.Under the optimal condi-tions,the yield of exopolysaccharide may reach 1145.94μg/mL,and the viscosity of fermenting liquor may reach 9200 mPa·s.

Key words:Oligotrophic bacteria; Extracellular polysaccharide; Fermentation