Development of a mathematical model for a microbial denitrification co-culture system comprising acetogenic bacterium Sporomusa ovata and denitrifying bacterium Pseudomonas stutzeri

Abstract

Previous study has shown that co-culturing acetogenic bacterium Sporomusa ovata (SO), with denitrifying bacterium Pseudomonas stutzeri (PS), is a promising strategy to enhance the microbial denitrification for nitrate-contaminated groundwater remediation. However, the mutual effects and reaction kinetics of these two bacteria in the co-culture system are poorly understood. In this study, a mathematical model for this co-culture system was established to fill this knowledge gap. Model simulation demonstrated that SO had a significant effect on the kinetics of denitrification by PS, while PS slightly affected the kinetics of acetate production by SO. The optimal initial HCO3-/NO3- ratio and SO/PS inoculation ratio were 0.77–1.48 and 67 for the co-culture system to achieve satisfied denitrification performance with less acetate accumulation. Finally, the minimum hydrogen supply was recommended when the initial bicarbonate and nitrate concentrations were assigned in the range of 2–20 mM and 2–4 mM for simulating the natural nitrate-contaminated groundwater treatment. These findings could provide useful insights to guide the operation and optimization of the denitrification co-culture system. HIGHLIGHTS A mathematical model for the co-culture system comprising Sporomusa ovata and Pseudomonas stutzeri was proposed.; The mutual effects between these two bacteria were revealed.; The optimal initial HCO3−/NO3− ratio was 0.77–1.48 for the co-culture system to achieve satisfied denitrification performance.; The minimum hydrogen supply was simulated under different bicarbonate and nitrate concentration conditions.;

Keywords

• acetate accumulation
• co-culture system
• denitrification performance
• mathematical model