pH-dependent biohydrogen production by Clostridium acetobutylicum and Clostridium butyricum bacteria

In this study, the pH-dependent hydrogen production efficiency of Clostridium acetobutylicum and Clostridium butyricum has been investigated. The bacteria have been identified using the MALDI-Tof MS method, and their hydrogenase genes have been determined via Real-Time PCR. It has been found that C. acetobutylicum harbors active hydA1, hydA2, hydA3, hydA4, hydA5, and hydA8 genes, while C. butyricum contains hydA8, hydB2, and hydB3 genes. At pH 6.0, the cumulative gas yield has been 19.963 L, with a gas composition of 54% H₂ and 45% CO₂. Accordingly, the hydrogen yield per mole of glucose has been calculated as 1.51 mol H₂/mol glucose. At pH 5.5, the cumulative gas yield has been 17.241 L, with 48% H₂ and 45% CO₂, resulting in a hydrogen yield of 1.28 mol H₂/mol glucose. At pH 5.0, the cumulative gas yield has been 8.63 L, with 45% H₂ and 45% CO₂, yielding 1.16 mol H₂/mol glucose. The optimum pH for hydrogen production using C. acetobutylicum and C. butyricum has been determined to be 6.0. These bacterial species have been determined to be suitable candidates for biohydrogen production. Maintaining a stable pH of 6.0 in biohydrogen production processes using C. acetobutylicum and C. butyricum may enhance hydrogen production and improve process efficiency Keywords: C. Asetobutylicum, C. Butyricum, Hydrogen Production, pH