This work is aimed at evaluating 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 (T. neapolitana, T. petrophila, T. naphtophila, T. maritima) were compared at 77 °C by means of tests conducted in 120-mL batch bioreactors containing a nutrient-rich growth medium (ATCC 1977; Van Ooteghem et al., Biotechnol. Lett., 2004, 26:1223) additioned with glucose, molasses or cheese whey as carbon source. For all the substrates tested, T. neapolitana resulted the best-performing strain under suspended-cell conditions, with a 0.9-1.9 mmol / L medium / h H2 production rate at an 8-10 g/L initial substrate concentration, and a 1.6-2.6 mmol H2 / mmol monosaccharide consumed yield. To compare the 4 strains also under attached-growth conditions, preliminary tests were conducted with glucose-growing T. neapolitana, with the goal to select the best biomass carrier among 4 porous materials utilized in biofiltration applications. The best results were obtained with the carrier characterized by the highest interfacial area, equal to 2.1 m2 g-1. Also under attached-growth conditions, T. neapolitana resulted the best strain for all the 3 substrates tested, with a 1.2-1.8 mmol / L medium / h H2 production rate. Further tests, aimed at simplifying the growth medium composition, led to encouraging results. For example, in the case of molasses a minimum medium composed only by NH4Cl, K2HPO4, NaCl, buffer and cysteine resulted – in comparison with the ATCC 1977 complete medium – in a 73% reduction of medium cost and in a 12% increase of the H2/substrate yield. Finally, the process scale-up to a 19-L reactor is in progress. The preliminary results indicate that, in the scale-up of batch H2 production from glucose by T. neapolitana, the values of the three monitored yields (H2/substrate, organic acids/substrate, biomass/substrate) did not show significant variations, whereas the H2 volumetric production and the initial H2 production rate resulted to be significantly affected by the concentration of the initial inoculum.

Batch tests of biological hydrogen production from food industry wastes by four thermotoga thermophilic strains in 0.12-L microcosms and in a 19-L fermentor

ALBERINI, ANDREA;BUCCHI, GIACOMO;CAPPELLETTI, MARTINA;PINELLI, DAVIDE;FEDI, STEFANO;FAVA, FABIO;FRASCARI, DARIO
2012

Abstract

This work is aimed at evaluating 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 (T. neapolitana, T. petrophila, T. naphtophila, T. maritima) were compared at 77 °C by means of tests conducted in 120-mL batch bioreactors containing a nutrient-rich growth medium (ATCC 1977; Van Ooteghem et al., Biotechnol. Lett., 2004, 26:1223) additioned with glucose, molasses or cheese whey as carbon source. For all the substrates tested, T. neapolitana resulted the best-performing strain under suspended-cell conditions, with a 0.9-1.9 mmol / L medium / h H2 production rate at an 8-10 g/L initial substrate concentration, and a 1.6-2.6 mmol H2 / mmol monosaccharide consumed yield. To compare the 4 strains also under attached-growth conditions, preliminary tests were conducted with glucose-growing T. neapolitana, with the goal to select the best biomass carrier among 4 porous materials utilized in biofiltration applications. The best results were obtained with the carrier characterized by the highest interfacial area, equal to 2.1 m2 g-1. Also under attached-growth conditions, T. neapolitana resulted the best strain for all the 3 substrates tested, with a 1.2-1.8 mmol / L medium / h H2 production rate. Further tests, aimed at simplifying the growth medium composition, led to encouraging results. For example, in the case of molasses a minimum medium composed only by NH4Cl, K2HPO4, NaCl, buffer and cysteine resulted – in comparison with the ATCC 1977 complete medium – in a 73% reduction of medium cost and in a 12% increase of the H2/substrate yield. Finally, the process scale-up to a 19-L reactor is in progress. The preliminary results indicate that, in the scale-up of batch H2 production from glucose by T. neapolitana, the values of the three monitored yields (H2/substrate, organic acids/substrate, biomass/substrate) did not show significant variations, whereas the H2 volumetric production and the initial H2 production rate resulted to be significantly affected by the concentration of the initial inoculum.
A. Alberini; S.J. Mendes; G. Bucchi; C. Manfreda; M. Cappelletti; D. Pinelli; S. Fedi; F. Fava; D. Frascari
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/115421
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