Fig. 7.

Influence of substrate load on SPS saccharification with or without substrate feeding. “4 + 4” with 40 g/L initial substrate and 40 g/L SPS was supplemented at 6th day; “8”, 80 g/L SPS was supplemented to initiate a batch saccharification process; “4 + 2 + 2” with 40 g/L or 20 g/L initial substrate and 20 g/L SPS were subsequently added at the 6th and 12th day; “2 + 2 + 2”, with initial substrate and 20 g/L SPS were added at the 6th and 12th day. The inoculum size was 1%. The saccharification process was divided into two or three phases based on the time points of substrate feeding (indicated by arrows with corresponding colors). The slopes and R² values of the linear trend lines were calculated for all phases, and are shown in the table. The slope values stand for the sugar production rates (g/L/day). Three independent experiments were performed to determine the average values and standard errors