BioChem - DOS

Stability problems in the hydrogen production by dark fermentation: Possible causes and solutions

Renewable & sustainable energy reviews

Castelló , Elena; Nunes Ferraz-Junior, Antonio Djalma; Andreani, Cristiane; Anzola-Rojas, Melida del Pilar; Borzacconi, Liliana; Buitró n, Germá n; Carrillo-Reyes, Juliá n; Gomes, Simone Damasceno; Maintinguer, Sandra I.; Moreno-Andrade, Ivá n; Palomo-Briones, Rodolfo; Razo-Flores, Elí as; Schiappacasse-Dasati, Marí a; Tapia-Venegas, Estela; Valdez-Vá zquez, Idania; Vesga-Baron, Alejandra; Zaiat, Marcelo; Etchebehere, Claudia

<P><B>Abstract</B></P> <P>H<SUB>2</SUB> production by dark fermentation using mixed cultures has been studied intensively during the last two decades, and its feasibility has been demonstrated. Different substrates, operational conditions, and reactor technologies have been widely studied and there is a general agreement that the use of non-sterile fermentable substrates is required to make the process feasible for scaling up. Nonetheless, stability problems during long term operation may hinder its application at large scale. This work, written by members of the Latin American Biohydrogen Network, analyse and discuss instability causes and possible solutions in the H<SUB>2</SUB> production by dark fermentation. It is concluded that instability is mostly linked to the biotic aspects of the process (i.e., changes in the microbial community composition, presence of organisms that consume hydrogen and compete for the substrate, and accumulation of fermentation products); regardless of the reactor configuration. However, some problems like excessive growth of microorganisms and methanogens presence were mostly reported in fixed bed reactors and granular sludge reactors. The novelty of this work relies on the comprehensive revision of the main causes behind the unstable and low hydrogen production and how these causes are linked to the technology used. The strategies to overcome the problems as well as the potential implications are also analysed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> MCF is crucial for scaling-up but is associated with stability and productivity problems. </LI> <LI> Homoacetogenesis (5&ndash;75% total acetate) and LAB are independent of the reactor configuration. </LI> <LI> Methane has been reported frequently in UASB or EGSB H<SUB>2</SUB>-producing reactors (e.g. 20% CH<SUB>4</SUB> versus 1% H<SUB>2</SUB> in a UASB). </LI> <LI> Many stability and productivity issues are associated with the process itself. </LI> <LI> Inoculum treatment, gas removal and reactor operational conditions contribute to stable H<SUB>2</SUB> production. </LI> </UL> </P>

2020

Elsevier

1364-0321

1879-0690

119

pp.109602

10.1016/j.rser.2019.109602

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART98722521

Biohydrogen production; Dark fermentation; H2 production microbiology; Unstable H2 production; Homoacetogenesis; Lactic acid bacteria