Effect of nitrogen gas sparging on dark fermentative biohydrogen production using suspended and immobilized cells of anaerobic mixed bacteria from potato waste

摘要

Biohydrogen is emerging as a suitable alternative to fossil fuels and has received worldwide popularity in recent years due to its economic, social and environmental benefits. This study was carried out to evaluate the effect of nitrogen gas sparging on dark fermentative biohydrogen production using suspended and immobilized cells of anaerobic mixed sludge. A maximum biohydrogen fraction of 56.98% which corresponded to a biohydrogen yield of 294.83 mL H-2/g Total Volatile Solids (TVS) was achieved in a dark fermentation process using N-2-sparged cells that were immobilized in calcium alginate beads. The biohydrogen production yield from the N-2-sparged immobilized cells was 1.8 and 2.5 times higher than that of sparged suspended cells and non-sparged (control) suspended cells, respectively. Therefore, the synergistic effect of nitrogen gas sparging and cell immobilization was instrumental in inhibiting the biohydrogen-scavenging bacteria during the dark fermentation process, thereby enhancing the yield. These findings could pave the way for the development of a large-scale biohydrogen production process from biowaste feedstocks.