Introducing capnophilic lactic fermentation in a combined dark-photo fermentation process: a route to unparalleled H2 yields

• Published in: Applied microbiology and biotechnology Vol. 99; no. 2; pp. 1001 - 1010
• Main Authors: Dipasquale, L, Adessi, A, d’Ippolito, G, Rossi, F, Fontana, A, De Philippis, R
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 2015; Springer Berlin Heidelberg; Springer Nature B.V
• Subjects: Acids; Alternative energy sources; Bacteria; Biodiesel fuels; Bioenergy and Biofuels; Biohydrogen; Biomedical and Life Sciences; Biotechnology; Carbon dioxide; Culture Media; effluents; feedstocks; Fermentation; Glucose; Glucose - metabolism; Hydrogen; Hydrogen - metabolism; Hydrogen production; Lactic Acid - metabolism; lactic fermentation; Life Sciences; Metabolism; Microbial Genetics and Genomics; Microbiology; Microorganisms; Models, Molecular; Oxidation; Rhodopseudomonas - metabolism; Rhodopseudomonas palustris; Seawater; Studies; Thermotoga neapolitana; Thermotoga neapolitana - metabolism; wastes; Photofermentation; Biological hydrogen production; Capnophilic lactic fermentation
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-014-6231-4

Two-stage process based on photofermentation of dark fermentation effluents is widely recognized as the most effective method for biological production of hydrogen from organic substrates. Recently, it was described an alternative mechanism, named capnophilic lactic fermentation, for sugar fermentation by the hyperthermophilic bacterium Thermotoga neapolitana in CO₂-rich atmosphere. Here, we report the first application of this novel process to two-stage biological production of hydrogen. The microbial system based on T. neapolitana DSM 4359ᵀand Rhodopseudomonas palustris 42OL gave 9.4 mol of hydrogen per mole of glucose consumed during the anaerobic process, which is the best production yield so far reported for conventional two-stage batch cultivations. The improvement of hydrogen yield correlates with the increase in lactic production during capnophilic lactic fermentation and takes also advantage of the introduction of original conditions for culturing both microorganisms in minimal media based on diluted sea water. The use of CO₂during the first step of the combined process establishes a novel strategy for biohydrogen technology. Moreover, this study opens the way to cost reduction and use of salt-rich waste as feedstock.