Optimization of simultaneous dark fermentation and microbial electrolysis cell for hydrogen production from macroalgae using response surface methodology

Abstract

In this study, H2 production from macroalgae by simultaneous dark fermentation (DF) and microbial electrolysis cell (MEC) in a single reactor, sDFMEC, was investigated, and the effects of particle size of substrate, temperature, initial pH, and substrate concentration on the sDFMEC performance was determined. The sDFMEC process were statistically optimized using a response surface method. The optimum substrate particle size achieved was 0.5–1.0 mm; however, it was not sufficiently significant because of the two-dimensional (2D) nature of the macroalgae substrate. However, the temperature, initial pH, and substrate concentration considerably affected the performance of sDFMEC. Based on the response surface analysis, the optimum conditions for a maximum H2 yield of 492.3 ± 5.1 mL/g-TS were as follows: temperature of 36.6 °C, initial pH of 7.44, and substrate concentration of 1.98 g/L. Under these operating conditions, the total energy efficiency achieved was 32.3 ± 0.2%. The results indicate that sDFMEC can be used as a promising method to produce H2 from macroalgae. © 2021 Elsevier B.V.