Bio-hydrogen production by SSF of paper industry wastes using anaerobic biofilms: A comparison of the use of wastes with/without pretreatment

In this research, we carried out the process of simultaneous saccharification and fermentation (SSF) of paper industry wastes with/without chemical pretreatment, using reactors in batch with anaerobic biofilms developed in spheres covered with ixtle fiber cord. Biofilms were previously developed a UASB reactor using anaerobic sludge with acid/thermal pretreatment to remove hydrogen consuming bacteria. Subsequently, the process of saccharification and simultaneous fermentation (SSF) of paper industry waste without chemical pretreatment was evaluated using batch reactors with developed anaerobic biofilms. The key process parameters were: pH (4, 5 and 6) and enzyme loading of Celluclast enzyme (10, 40 and 70 FPU) at a temperature of 45° C The results for hydrogen production with paper industry wastes without pretreatment showed optimal working conditions to maximize hydrogen production by SSF process at: pH (5) and an enzyme load of 70 FPU, so the maximum hydrogen yield obtained was 31.188 mmol/h × gSV. The results obtained from the evaluation of the process of SSF performed with paper industry wastes subjected to chemical pretreatment with H2SO4 2.5% showed the optimum working conditions to maximize hydrogen production: pH (4), an enzyme load of 70 FPU, the maximum value of hydrogen yield obtained was 55 844 mmol/h *gSV. The key process parameters were optimized by the response surface methodology (RSM) based on a two factor-three level central composite design (CCD), using as variables: pH (4.5 and 6), enzyme loading of Celluclast® (10, 40 and 70 UPF) and temperature (45 °C), for paper industry wastes with/without acid pretreatment. The results showed the analysis of variance was performed to test the importance of the polynomial equation of second order, so equations obtained for both residues (with/without pretreatment) describe the hydrogen yield in this study.