Effects of different nitrogen sources on production of EPS
In the case of nitrogen source, the highest EPS level among the
five different nitrogen sources was with soy peptone, the production
of EPS reached up to 150 mg/L (Fig. 3). When the concentration of
soy peptone was increased from 5 to 30 g/L, the EPS yield was significantly
increased. The EPS production was 250 mg/L when the concentration
of soy peptone reached up to 30 g/L (Fig. 4), which was
4.2-fold higher than that produced under the non-optimal fermentation
condition. In this study, the optimal fermentation condition
was defined as 10% RSM with 80 g/L sucrose and 30 g/L soy peptone
at an initial pH 7.0 and 37 C for 30 h.