Optimizing Performance of a Microbial Carbon-Capture Cell using Box-Behnken Design

Abstract Performance of a microbial carbon-capture cell (MCC), in which a microbial fuel cell and a photo-bioreactor gets mutually benefitted, is reliant on certain critical factors. In present investigation, Box-Behnken design is adopted to statistically evaluate the effect of influential parameters, namely nitrate concentration in catholyte, photoperiod and concentration of lipid extracted algae (LEA) of mixed culture microalgae in the anodic inoculum, on the performance of MCC. As per validation experiment, based on statistical model prediction, the ideal performance (higher power density and algal productivity) was achieved at LEA concentration, nitrate concentration and photoperiod in a range of 5.3-5.7 g/L, 44-50 mg/L and 10.00-10.67 h, respectively. Furthermore, the accuracy of model predictions was successfully validated by operating a separate MCC, which gave a power density and algal productivity (7.12 ± 0.09 W/m3 and 0.83 ± 0.02 g/L.day) close to the predicted output (7.05 ± 0.13 W/m3 and 0.838 ± 0.019 g/L.day). Box-Behnken design aided in optimizing the influential factors so as to make MCC economical and efficient for scale-up.