Sustainable hydrogen production is a topic of great interest since hydrogen is considered a clean, high-energy content and a low emission fuel. According to this, biological hydrogen production, especially from organic residues, is an attractive process, combining clean energy generation with waste material recycling[1]. Since hydrogen fermentative production at high temperature benefits of general and thermodynamics advantages, hyperthermophilic Thermotoga species are considered ideal organisms for H2 production[2]. The aim of this study is to investigate the feasibility of a cost-effective process of biological H2 production from food industry wastes under thermophilic conditions. The H2-producing performances of 4 Thermotoga strains (Th. neapolitana, Th. petrophila, Th. naphtophila, Th. maritima) were compared at 77 °C by means of tests conducted in 120-mL batch bioreactors containing 40 mL of a nutrient-rich growth medium (ATCC 1977)[3] supplemented with glucose, molasses or whey as main carbon sources. For all the substrates tested, Th. neapolitana resulted the best-performing strain, with a H2 specific production rate of 0.50-0.68 mmol gdry weight-1 h-1 at a 10 g L-1 initial substrate concentration. The H2-producing capacities of the 4 strains were also evaluated under biofilm-growth conditions by using a porous ceramic support utilized in the field of biofiltration as biomass carrier. Also under attached-growth conditions, Th. neapolitana resulted the best strain for all the 3 substrates tested, with a H2 specific production rate of 0.09-0.18 mmol gdry weight-1 h-1. Further tests were aimed at optimizing the growth medium composition. As a result, a significantly more simple – and thus more economical – medium was obtained that allowed the development of a more cost-effective process, even though the resulting H2 production rates were lower than those obtained by growing Thermotoga on the rich medium ATCC 1977. Finally, the preliminary results of a kinetic study of H2 production by attached cells of Th. neapolitana with glucose, molasses and whey indicated a substrate inhibition effect above 20 g L-1 for glucose and whey, but not for molasses.
Cappelletti M., Bucchi G., Mendes S.J., Alberini A., Frascari D., Fedi S., et al. (2011). HYDROGEN PRODUCTION BY HYPERTHERMOPHILIC THERMOTOGA SPP. FROM FOOD INDUSTRY WASTE.
HYDROGEN PRODUCTION BY HYPERTHERMOPHILIC THERMOTOGA SPP. FROM FOOD INDUSTRY WASTE
CAPPELLETTI, MARTINA;BUCCHI, GIACOMO;ALBERINI, ANDREA;FRASCARI, DARIO;FEDI, STEFANO;PINELLI, DAVIDE;BERTIN, LORENZO;FAVA, FABIO;ZANNONI, DAVIDE
2011
Abstract
Sustainable hydrogen production is a topic of great interest since hydrogen is considered a clean, high-energy content and a low emission fuel. According to this, biological hydrogen production, especially from organic residues, is an attractive process, combining clean energy generation with waste material recycling[1]. Since hydrogen fermentative production at high temperature benefits of general and thermodynamics advantages, hyperthermophilic Thermotoga species are considered ideal organisms for H2 production[2]. The aim of this study is to investigate the feasibility of a cost-effective process of biological H2 production from food industry wastes under thermophilic conditions. The H2-producing performances of 4 Thermotoga strains (Th. neapolitana, Th. petrophila, Th. naphtophila, Th. maritima) were compared at 77 °C by means of tests conducted in 120-mL batch bioreactors containing 40 mL of a nutrient-rich growth medium (ATCC 1977)[3] supplemented with glucose, molasses or whey as main carbon sources. For all the substrates tested, Th. neapolitana resulted the best-performing strain, with a H2 specific production rate of 0.50-0.68 mmol gdry weight-1 h-1 at a 10 g L-1 initial substrate concentration. The H2-producing capacities of the 4 strains were also evaluated under biofilm-growth conditions by using a porous ceramic support utilized in the field of biofiltration as biomass carrier. Also under attached-growth conditions, Th. neapolitana resulted the best strain for all the 3 substrates tested, with a H2 specific production rate of 0.09-0.18 mmol gdry weight-1 h-1. Further tests were aimed at optimizing the growth medium composition. As a result, a significantly more simple – and thus more economical – medium was obtained that allowed the development of a more cost-effective process, even though the resulting H2 production rates were lower than those obtained by growing Thermotoga on the rich medium ATCC 1977. Finally, the preliminary results of a kinetic study of H2 production by attached cells of Th. neapolitana with glucose, molasses and whey indicated a substrate inhibition effect above 20 g L-1 for glucose and whey, but not for molasses.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
