Modelling and optimization of operational setpoint parameters for maximum fermentative biohydrogen production using box-behnken design

Abstract

Fermentative biohydrogen production has been flagged as a future alternative energy source due to its various socio-economical benefits. Currently, its production is hindered by the low yield. In this work, modelling and optimization of fermentative biohydrogen producing operational setpoint conditions was carried out. A box-behnken design was used to generate twenty-nine batch experiments. The experimental data were used to produce a quadratic polynomial model which was subjected to analysis of variance (ANOVA) to evaluate its statistical significance. The quadratic polynomial model had a coefficient of determination (R 2 ) of 0.7895. The optimum setpoint obtained were potato-waste concentration 39.56 g/L, pH 5.56, temperature 37.87 ° C, and fermentation time 82.58 h, predicting a biohydrogen production response of 537.5 mL H 2 /g TVS. A validation experiment gave 603.5 mL H 2 /g TVS resulting to a 12% increase. The R 2 was above 0.7 implying the model was adequate to navigate the optimization space. Therefore, these findings demonstrated the feasibility of conducting optimized biohydrogen fermentation processes using response surface methodology.