Carbon Dioxide Utilization for an Enhanced Biohydrogen Production of a Biomass Hydrolysate

Abstract

Bio-hydrogen (H 2 ) production in a thermophilic anaerobic bioreactor with carbon dioxide (CO 2 ) utilization at the headspace was investigated at different ratio of Biomass substrate to Microorganism (B/M). A 3 mL volume of 80% NaOH (m/v) solution was continuously hung at the headspace of the bioreactors to capture carbon dioxide. The utilization of CO 2 at its headspace, proved to enhance bio H 2 production. The highest Cumulative Biohydrogen Yield (CHY) of 131.81±3.47 mL-H 2 /gVS was measured at the ratio of 8.10 parts of biomass to 0.90 parts of Acclimatized Seed Sludge (ASS), B/M 9, while 4.17 parts of similar biomass to 0.83 parts of ASS (B/M 5) had a biohydrogen production of 90.70±16.67 mL-H 2 /gVS. The B/M of 6.12 parts of biomass to 0.88 parts of ASS (B/M 7) produced a CHY of 84.72±18.35 mL-H 2 /gVS while the control bioreactors without CO 2 utilization (without and with biomass substrate) yielded a 0.06±0.035 mL-H 2 /gVS and a 3.27±0.78 mL-H 2 /gVS respectively. The mechanism of the biofermentation in this anaerobic reaction produced two possible resulting reaction; the acetogenesis of CO 2 with H 2 and the hydrogenotrophic methanogenesis. These reactions consumes hydrogen in the process to produce methane or acids. The presence of 80% (m/v) NaOH solution at the headspace inside the bioreactors, utilizes the CO 2 producing a hydrogen-rich region in space: The highest average H 2 yield of 51.83 mL-H 2 after 49.1 h with B/M 9 without methane was due to carbon dioxide utilization in the bioreactors. A univariate ANOVA and Pair-wise Tukey HSD statistical analysis revealed that the CHY of B/M9 was significantly higher than the other B/Ms. The highest yield, 55.85 mL-H 2 /gVS obtained with the bioreactor of B/M 9 was optimum for H 2 production. The results concluded that H 2 production is also enhanced by CO 2 utilization at the headspace.

Biohythane production from pineapple peel using Methanosarcina mazei enhanced with palm oil mill effluent (POME) sludge in single‐stage anaerobic digestion

“…In most cases, carbon dioxide's by‐productivity had no apparent relation with biohythane production. However, a study by Abug and Oh (2016) found that the presence of carbon dioxide inside the bioreactors improved the performance of the hydrogen production process. Therefore, cumulative carbon dioxide side production is also depicted in Exhibit 3 to observe whether carbon dioxide significantly impacts biohydrogen production.…”