Figure 7
Effect of nitrogen sources and contents on the production of FFAs. The FFAs production (a) and cell densities (b) of the cultures supplemented with 5 g/L beef extract powder, beef extract, yeast extract and tryptone, respectively; The FFAs production (c) and cell densities (d) of the cultures supplemented with different contents of tryptone. The 5 g/L tryptone culture achieved the highest titer of FFAs (716.1 mg/L), with a medium cell density.