Impact of Glucose Concentration on Hydrogen Production Efficiency in Microalgal-Cyanobacterial-Bacterial Co-Cultures (Student Poster #12)

Abstract Description: This study investigated bio-photolytic hydrogen (H2) production using a co-culture of Chlamydomonas reinhardtii, Phormidium keutzingium, and activated sludge bacteria. The research focused on the impact of glucose concentration (2.5, 5, 10, and 20 g/L) on H2 yield and associated gas production. Peak H2 production increased with glucose concentration, reaching 729.9 mL L⁻¹ (50.5%) at 20 g/L, 602.0 mL L⁻¹ (45.5%) at 10 g/L, 523.5 mL L⁻¹ (43.9%) at 5 g/L, and 208.4 mL L⁻¹ (38.7%) at 2.5 g/L. Oxygen (O2) levels remained low, averaging 1.7% of total gas production. Nitrogen (N2) and carbon dioxide (CO2) constituted approximately 23.8% and 25.8% of the total gas volume, respectively. pH levels decreased over time for all glucose concentrations, starting between 7.51-9.06 and ending between 3.62-5.01. The pH decline, correlated with acetate accumulation, influenced gas production trends, with output decreasing as pH approached lower limits. The results demonstrate a clear inverse correlation between H₂ production and O₂ levels, while simultaneously showing an increase in H₂ yield with rising glucose concentrations. The co-culture approach with activated sludge bacteria significantly enhanced H2 output, showcasing its potential for efficient bio-hydrogen production. This method offers promising avenues for scalable and sustainable H2 generation in biotechnological applications, which are essential for addressing global energy challenges.

Keywords: H2 production, Chlamydomonas reinhardtii, activated sludge bacteria, glucose, pH