Study of factors involved in the behavior of biofilms formed by biohydrogen-producing microflora identified by molecular biology using dairy wastewater

• Published in: International journal of hydrogen energy 2021-07, Vol.46 (51), p.25965-25973
• Main Authors: Ayil-Gutiérrez, B.A., Tamayo-Ordoñez, M.C., Silva Belmares, S.Y., Morales-Martínez, T.K., Rodríguez-De la Garza, J.A., Medina Morales, M.A., Soria Ortiz, A.I., Gutiérrez Rodríguez, B., Ríos-González, L.J., Sosa Santillán, G.J., Moreno Dávila, I.M.M.
• Format: Article
• Language: English
• Subjects: Biohydrogen; Diary wastewater; Opuntia imbricata
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2021.06.039

Batch tests were carried out to investigate the production of H2 considering the effects of: substrate concentration in a range of 3–25 g-COD/L; Initial pH: from 4 to 7 and 11 and temperatures of: 20, 35, 45 and 55 °C. The optimal substrate was 25 g-COD/L, with a reduction of COD of 73% and a yield of H2 of 5.95 mM/gCOD; and the optimal initial pH was 11.0, with a 70% of COD reduction and a H2 yield of 4236 mM/gCOD. The optimum temperature for pH = 11 was 35 °C, with a COD reduction of 69.8% and H2 yield of 6.3 mM/gCOD. Escherichia, Acinetobacter, Alcaligenes, Brevibacterium, Clostridium and Mycobacterium were isolated from pretreated inoculum samples and identified by 16S rDNA sequencing. The results suggest that biofilm reactors developed on a natural support such as Opuntia imbricata have good potential for hydrogen production from dairy wastewater. •Anaerobic sludge useful as inoculum for H2 production.•Effects of temperature/substrate/pH on biohydrogen production and for the development of biofilms.•Chemical-thermal pretreatments against methanogens.•Metagenomic analysis of the pretreated mixed microflora.