Impact of furfural on biological hydrogen production kinetics from synthetic lignocellulosic hydrolysate using mesophilic and thermophilic mixed cultures

Hydrogen production by Enterobacter sp. LBTM 2 using sugarcane bagasse hemicellulose hydrolysate and a synthetic substrate: understanding and controlling toxicity

“…The yield of hydrogen production is usually related to the metabolic route, being the highest when acetic acid is the main product (C 6 H 12 O 6 +2H 2 O → 2CH 3 COOH + 2CO 2 +4H 2 ) followed by butyric acid ( C 6 H 12 O 6 → 2CH 3 CH 2 CH 2 COOH + 2CO 2 +2H 2 ) (Nasr et al 2014). This is probably because hydrogen production is affected by intracellular NADH levels, since under higher levels of such electron carrier more reduced metabolic products, such as ethanol, lactic acid and propionic acid, are produced (Akobi et al 2017). This can be seen for propionic acid production in which hydrogen is actually consumed (C 6 H 12 O 6 + 2H 2 → 2CH 3 CH 2 COOH + 2H 2 O).…”

“…Similarly, Nasr et al (2014) found that hydrogen production rates and yields were not affected by furfural concentrations in the range of 0.21 to 1.09 g/L. On the other hand, the impact of furfural addition on hydrogen production and yields was evaluated by Akobi et al (2017) who reported that a furfural concentration up to 1 g/L increased hydrogen production by 19%, while at 4 g/L there was a decrease in hydrogen production, which was only re-established when furfural was completely degraded. In the present work it was observed a delay on hydrogen production by 0.3 g/L furfural addition, indicating that hydrogen accumulation started only when when furfural was no longer present in the medium.…”

A novel permeable reactive biobarrier for ortho-nitrochlorobenzene pollution control in groundwater: Experimental evaluation and kinetic modelling

“…where 𝑅 𝑠 is the rate of substrate consumption (mol L -1 s -1 ), 𝜇 𝑚𝑎𝑥 is the maximum growth rate (s -1 ), 𝑋 is the biomass concentration (mol L -1 ), 𝑌 𝑋 is the microbial yield coefficient (mol biomass C/mol substrate C), 𝐶 𝐻 2 is the concentration of dissolved molecular hydrogen acting as an electron donor (mol L -1 ), 𝐾 𝐻 2 is the half-maximum rate hydrogen concentration (mol L -1 ), 𝑆 is the aqueous concentration of the substrate (o-NCB) acting as an electron acceptor (mol L -1 ), 𝐾 𝑠 is the half-maximum rate substrate concentration (mol L -1 ), 𝐶 1 is the concentration of o-CAN, the degradation product of o-NCB (mol L -1 ), and 𝐾 1 is the relative inhibition constant (mol L -1 ). The double Monod kinetics parameters were taken from prior studies related to the removal of chlorinated or organic compounds (Acharya et al, 2019;Akobi et al, 2017;la Cecilia and Maggi, 2016;Malaguerra et al, 2011;Schafer et al, 1998), so as to obtain the best fit of the model to the experimental results. The change in the substrate was related to the amount of biomass according to the relationship:…”

“…where 𝑅 𝑠 is the rate of substrate consumption (mol L -1 s -1 ), 𝐶 𝑜𝑐 is the concentration of dissolved organic carbon (mol L -1 ), and 𝐾 𝑜𝑐 is the half-maximum rate organic carbon concentration (mol L -1 ). The parameters for Monod kinetics were obtained from prior reports concerning the consumption of organic compounds (Akobi et al, 2017;Carboneras et al, 2017;la Cecilia and Maggi, 2016;Vasiliadou et al, 2015;Verce et al, 2000). The support of microbial growth by dissolved organic carbon could be expressed by equation ( 5).…”

“…a 𝑘 1 = 6.42×10 -6 a Data obtained based on Table S4; b Data from (la Cecilia and Maggi, 2016); c Data from (Malaguerra et al, 2011); d Data from (Carboneras et al, 2017); e Data from (Vasiliadou et al, 2015); f Data from (Verce et al, 2000); g Data from (Akobi et al, 2017); h Data from (Chen and McTernan, 1992); i Data from (Acharya et al, 2019); j Data from (Schafer et al, 1998).…”