Kinetic modeling of fermentative hydrogen production by Thermotoga neapolitana

A kinetic model of fermentative hydrogen (H₂) production was developed for the hyperthermophilic marine bacterium Thermotoga neapolitana DSMZ 4359^T using glucose as the substrate. The model was built based on anaerobic digestion model no.1 (ADM1) by IWA using Monod-like kinetic equations. Several series of pH controlled batch fermentation tests were performed under pure CO₂ or N₂ atmosphere in serum bottles to evaluate the growth kinetic parameters. The kinetic parameters were estimated by applying the non-linear least square method to Monod and Michaelis–Menten kinetic equations. The experimentally estimated value of k, k_S, Y and k_d were 0.839 h⁻¹, 1.42 g/L, 0.1204 and 0.0043 h⁻¹, respectively. The kinetic parameters were analyzed for sensitivities and subsequently calibrated and validated by a separate set of experimental results. The model was particularly effective in estimating the biomass growth, substrate consumption, and H₂ production except for acetate and lactate production, due to capnophilic condition (under CO₂ atmosphere).