Synergetic effect evaluation of light and mass transfer enhancement strategies on photo fermentative biohydrogen production process: Illumination, shake, and high solid level

During the process of photo fermentative biohydrogen production (PFHP) with high substrate concentration from agricultural waste, the interphase light and mass transfer behavior is hindered, caused by the suspension flow of substrates, resulting in low hydrogen production performance. In the paper, shake and lighting supplied strategy was investigated to soften the restrictions of high substrate concentration of corncob to improve the hydrogen yield and light energy conversion. The response surface methodology (RSM) was adopted to optimize the influence of variables on hydrogen production (substrate concentration, light intensity and shake intensity). Results showed that the maximum hydrogen yield of 48 mL/g TS and the maximum light energy conversion efficiency of 11.04% were obtained at the condition of 150 rpm, 6000 Lux and substrate concentration 55.56 g/L, increased by 603.85% and 598.63% than the static condition, respectively. RSM showed the synergistic effect between variables significantly affected the hydrogen production performance, the optimal enhancement strategies were: shake intensity 153.33 rpm, light intensity 6155.56 Lux and substrate concentration 57.71 g/L. 4.71% error of the predicted cumulative hydrogen yield (490.41 mL) and the actual cumulative hydrogen yield (468.34 mL) indicating the fitting effect of the model was satisfactory.