Nutrients related to spore germination improve H2 production from heat-shock-treated consortia

The effect of supplementation of specific nutrients related to spore germination on batch hydrogen production from heat-shock-pretreated (HSP) consortia and organic solid waste was studied. A 2 × 3 general factorial design was used to evaluate the effect of incubation temperature (two levels) and addition of specific nutrients for spore germination, named germinants (three levels) on hydrogen production. l-Alanine alone (A1) and a mixture of germinants (A2) were used as specific nutrients as well as control without germinants (A3). The units were incubated at 37 °C (B1) or 55 °C (B2). The analysis of variance showed that both factors had highly significant effects on hydrogen production (p < 0.0001). The best performance was obtained in HSP units supplemented with l-alanine alone followed by the mixture of germinants whereas those HSP units without germinants supplementation had very poor H₂ production. The average results for incubation temperature showed that independently of germinant addition, the mesophilic regime showed higher H₂ production, likely related to more benign germination conditions, than thermophilic incubation. This study demonstrates that hydrogen batch production from HSP consortia and organic solid waste as substrate could be substantially improved by germinant supplementation, although more-detailed studies on individual germinants or germinant combinations and their concentrations are necessary.