A comparison between simultaneous saccharification and separate hydrolysis for photofermentative hydrogen production with mixed consortium of photosynthetic bacteria using corn stover

Two different process configurations SSP (simultaneous saccharification photo-fermentation) and SHP (separate hydrolysis photo-fermentation) for photo-fermentative hydrogen production using corn stover by mixed consortium of photosynthetic bacteria were compared. The effects of substrate concentration, initial pH and fermentative temperature on SSP and SHP were investigated. Cell growths and hydrogen production characteristics during the processes of SSP and SHP were also compared. The results showed that the optimal condition of SSP was substrate concentration of 30 g/L, initial pH of 5.5 and fermentative temperature of 40 °C, the corresponding hydrogen production was 83.87 mLH2/g corn stover, which was 27.8% higher than that of SHP. The cell growth time in SSP was longer than that in SHP, especially for extended exponential and stationary stages, which was helpful for hydrogen production. The highest cell concentration in SSP was 3.34 g/L, which was 36.3% higher than that of SHP. The peak hydrogen production rate in SSP increased linearly until 16.33 mL H2/h during 36-120 h, while the peak hydrogen production rate in SHP increased during 12-48 h and then decreased during 48-84 h, with a mean rate of 11.28 mL H2/h.