초록
Hydrogen (H<SUB>2</SUB>), a possible future clean energy carrier, requires process-based improvement routes for cutting down the production cost. The impact of nitrogen (N<SUB>2</SUB>) sparging on H<SUB>2</SUB> production during co-culture system of Enterobacter aerogenes and Clostridium butyricum from crude glycerol (CG) was studied to reduce the overall process cost. H<SUB>2</SUB> production using 1% CG under nitrogen sparged medium before autoclaving resulted in 1.2 mmol-H<SUB>2</SUB>/mol of glycerol in comparison to 1.5 mmol-H<SUB>2</SUB>/mol of glycerol without sparging. In the presence of air ranging from 5 mL to 75 mL in the headspace volume, H<SUB>2</SUB> production increased to a maximum of 26.14 mmol/L with 1.4 g/L of ethanol production. The concentration of 1,3-propanediol with N<SUB>2</SUB> sparging was around 3.0 g/L and decreased to 0.5 g/L due to presence of 75 mL of air in the headspace. This observation can be attributed to a shift from reductive to oxidative metabolism of glycerol. A process-based improvement strategy to optimize H<SUB>2</SUB> formation resulted in metabolic pathway shift from reductive to oxidative with increase in H<SUB>2</SUB> production. Synergistic influence of co-culture system in absence of expensive reducing agent and without nitrogen sparging step can offer a better process-based economic strategy for H<SUB>2</SUB> production, minimize the metabolite production and increase field-scale application of biodiesel plant.